Co-reporter:Hengyu Guo, Min-Hsin Yeh, Yunlong Zi, Zhen Wen, Jie Chen, Guanlin Liu, Chenguo Hu, and Zhong Lin Wang
ACS Nano May 23, 2017 Volume 11(Issue 5) pp:4475-4475
Publication Date(Web):April 12, 2017
DOI:10.1021/acsnano.7b00866
The development of lightweight, superportable, and sustainable power sources has become an urgent need for most modern personal electronics. Here, we report a cut-paper-based self-charging power unit (PC-SCPU) that is capable of simultaneously harvesting and storing energy from body movement by combining a paper-based triboelectric nanogenerator (TENG) and a supercapacitor (SC), respectively. Utilizing the paper as the substrate with an assembled cut-paper architecture, an ultralight rhombic-shaped TENG is achieved with highly specific mass/volume charge output (82 nC g–1/75 nC cm–3) compared with the traditional acrylic-based TENG (5.7 nC g–1/5.8 nC cm–3), which can effectively charge the SC (∼1 mF) to ∼1 V in minutes. This wallet-contained PC-SCPU is then demonstrated as a sustainable power source for driving wearable and portable electronic devices such as a wireless remote control, electric watch, or temperature sensor. This study presents a potential paper-based portable SCPU for practical and medical applications.Keywords: cut paper; self-charging power unit; supercapacitor; superportable; triboelectric nanogenerator;
Co-reporter:Xiaona Xia, Jie Chen, Guanlin Liu, Muhammad Sufyan Javed, Xue Wang, Chenguo Hu
Carbon 2017 Volume 111() pp:569-576
Publication Date(Web):January 2017
DOI:10.1016/j.carbon.2016.10.041
•Aligned graphene sheets in PDMS film (AGS@PDMS) is fabricated by spin-coating technique.•Influence of morphology and alignment of filling carbon materials in PDMS have been compared.•The AGS@PDMS film has larger energy storage ability and lower dielectric loss.•Voltage applied on the TENG is distributed to micro capacitors formed by AGSs.In this paper, aligned graphene sheets (AGS) embedded in PDMS (AGS@PDMS) has been prepared by repeated spin-coating (SC) technique. The triboelectric nanogenerator (TENG) based on the AGS@PDMS film is fabricated and its electric output is investigated systematically with different contents of filling graphene sheets and different spin-coating layers. The PDMS embedded with AGS is compared with that of disordered graphene sheets and graphite particles with different sizes. The capacitance, dielectric loss, conductivity and resistance of the PDMS composite film are characterized and analyzed. The output current of the TENG based on AGS@PDMS film is 3 times as much as that of the TENG based on pure PDMS film and the output power density reaches 4.8 W/m2 at the load resistance of 15 MΩ. In addition, the TENG can be used as a pressure sensor to measure the mass and height of an object. This work demonstrates that the voltage applied on whole TENG is distributed to micro capacitors formed by aligned graphene sheets in PDMS, by which the higher breakdown voltage and energy conversion ability are achieved.The TENG based on aligned graphene sheets embedded in PDMS has been fabricated by repeated spin-coating technique, which has the higher breakdown voltage and lower dielectric loss owning to the oriented distribution of graphene sheets and excellent output performance.
Co-reporter:Cuiling Zhang;Hao Hua;Jianlin Liu;Xiangyu Han;Qipeng Liu
Nano-Micro Letters 2017 Volume 9( Issue 4) pp:49
Publication Date(Web):19 July 2017
DOI:10.1007/s40820-017-0150-8
Ag–AgX(X = Cl, Br)@TiO2 nanoparticle-aggregated spheres with different mass ratio of R = TiO2/Ag(X) from 35:1 to 5:1 were synthesized by a facile sol–gel technique with post-photoreduction. The photocatalytic activities of both Ag–AgCl@TiO2 and Ag–AgBr@TiO2 under visible light are effectively improved by ~3 times relative to TiO2 NPAS under the simulated sunlight for the decomposition of methyl orange (MO). Ag–AgBr@TiO2 showed 30% improvement and less stable in photocatalytic activity than that of AgCl@TiO2.
The role of Ag and AgX nanoparticles on the surface of Ag–AgX(X = Cl, Br)@TiO2 was discussed. Ag on these samples not only can efficiently harvest visible light especially for AgCl, but also efficiently separate excited electrons and holes via the fast electron transfer from AgX(X = Cl, Br) to metal Ag nanoparticles and then to TiO2-aggregated spheres on the surface of heterostructure. On the basis of their efficient and stable photocatalytic activities under visible-light irradiation, these photocatalysts could be widely used for degradation of organic pollutants in aqueous solution.
Co-reporter:Lin Chen, Hao Hua, Qi Yang, Muhammad Sufyan Javed, ... Cuiling Zhang
International Journal of Hydrogen Energy 2017 Volume 42, Issue 9(Volume 42, Issue 9) pp:
Publication Date(Web):2 March 2017
DOI:10.1016/j.ijhydene.2016.12.028
•TiO2 microflowers assembled by nanosheets are prepared by a simple method.•Pt supported on anatase-TiO2(B) coexistence nanostructure is first used for alcohol oxidation.•The improved performance is obtained due to the enhanced conductivity and quick electron transfer.•The reaction electrons at Pt/anatase-TiO2 sites quickly transfer to TiO2(B) avoiding in-situ second reaction.TiO2 microflowers assembled by nanosheets are prepared by a one-step solvothermal process. The anatase-TiO2(B) dual-phase coexistence or anatase single phase is obtained under different annealing temperatures. Pt nanoparticles supported on the anatase-TiO2(B) microflowers are first applied to alcohol electrooxidation. The electrocatalytic performances of Pt/anatase-TiO2(B), Pt/anatase and Pt/carbon-black (Pt/C) on graphite substrates are systematically investigated. The Pt/anatase-TiO2(B) catalyst exhibits superior electrocatalytic activity and stability compared with that of Pt/anatase and Pt/C catalysts for methanol and ethanol in acidic and alkaline media, which is attributed to the large specific surface area, the porous channels to reduce the liquid sealing effect, the enhanced electronic conductivity by dual-phase coexistence and quick electron transfer from anatase phase to TiO2(B).Download high-res image (250KB)Download full-size imageThe released electrons at Pt/anatase-TiO2 sites from the oxidation of alcohol molecules are quickly transferred to TiO2(B) due to the dual-phase coexistence, which prevents the in-situ second reaction and intermediates on the electrode.
Co-reporter:Xu Weina, Liu Guanlin, Wang Chuanshen, Chenguo Hu, Xue Wang
Electrochimica Acta 2017 Volume 225(Volume 225) pp:
Publication Date(Web):20 January 2017
DOI:10.1016/j.electacta.2016.12.130
•β-MnO2 is selected as electrode material of enzymeless glucose sensor for the first time.•β-MnO2 micro/nanorod arrays directly grown on carbon fiber fabric is obtained by a simple method.•The β-MnO2 electrode towards electro-oxidation of glucose exhibits superior sensitivity.Intrinsic electrocatalytic activities of a material and electrode architecture for supporting the active material are crucial factors that determine the electrochemical sensing performance. In this work, tetragonal β-MnO2 is taken as an electrocatalytic material for enzymeless glucose sensing. To construct a three dimensional nanostructure electrode, β-MnO2 is directly grown on flexible carbon fiber fabric forming the micro/nanorod arrays (RA). For comparison, β-MnO2 micro/nanorod powder (RP) is immobilized on graphite electrode by Nafion binder. Both β-MnO2 RA and RP electrodes are investigated systematically as enzymeless glucose sensors and the results indicate the high sensitivity of 1650.6 μA mM−1 cm−2, wide linear range up to 4.5 mM for the RA electrode, which shows much better performance than that of RA electrode. The sensitivity of RA electrode towards electro-oxidation of glucose is about 1.7-fold as much as that for RP electrode, mainly benefiting from the favorable electrode architecture. Besides, the RA electrode shows extraordinary stability, reproducibility and selectivity. Our investigation indicates that the electrode based on the β-MnO2 micro/nanorod array directly grown on carbon fiber fabric is outstanding candidate for high efficiency flexible enzymeless glucose sensing.Download high-res image (164KB)Download full-size image
Co-reporter:Wenlong Li;Hengyu Guo;Yi Xi;Chuanshen Wang;Muhammad Sufyan Javed;Xiaona Xia
RSC Advances (2011-Present) 2017 vol. 7(Issue 37) pp:23208-23214
Publication Date(Web):2017/04/24
DOI:10.1039/C7RA02709E
Wind, as a natural power source, can be used to produce electricity using wind generators. However, detecting wind velocity has been challenging because wind always blows in a random direction. In this study, we design a self-powered wind velocity sensor based on integrated wind-induced generating units (WGUs) to harvest wind energy from all directions in a plane and as a self-powered wind velocity sensor (denoted as WGUs sensor). A wind-induced generating unit consists of two parallel plate Cu-electrodes (size 1.5 × 4 cm2, gap 0.5 cm) and a polytetrafluoroethylene (PTFE) thin film between them. The W-TGUs sensor can be effectively used to harvest wind energy from all directions in a plane by integrating the W-TGUs in circular and vertical directions. The output current and voltage of every WGU are 1–3.5 μA, and 13–20 V under a wind speed of 6–27 m s−1. The output rectified current of WGUs, with vertically integrated one to five WGUs, was 1.3–6.8 μA under a wind speed of 8 m s−1. Moreover, the W-TGUs sensor can detect a wind velocity from all directions on a plane with a resolution ratio of 0.13 (m s−1) Hz−1 and a response time of 0.15 s, which is a very important advantage as a self-powered wind velocity sensor. The output power of the WGUs sensor can be greatly enhanced by increasing the number of WGUs. This study provides a novel design for harvesting wind energy and sensing wind velocity from a random direction on a plane.
Co-reporter:Muhammad Sufyan Javed, Nusrat Shaheen, Asim Idrees, Chenguo Hu, Rizwan Raza
International Journal of Hydrogen Energy 2017 Volume 42, Issue 15(Volume 42, Issue 15) pp:
Publication Date(Web):13 April 2017
DOI:10.1016/j.ijhydene.2017.02.045
•The LSZF perovskite oxides show the reduced area specific resistance at 550 °C.•Thermal expansion coefficient of the LSZF shows excellent compatibility with SDC electrolyte.•The LSZF is used as a cathode for direct natural gas based fuel cell at intermediate temperature.•Single fuel cell (NiO-SDC/SDC/LSZF) exhibits an outstanding performance with natural gas at 550 °C.A novel cobalt-free perovskite zinc-doped lanthanum strontium iron oxide (La0.8Sr0.2ZnxFe1−xO3−δ, LSZF, x = 0.1–0.3) is synthesized and evaluated as cathode material for intermediate temperature solid oxide fuel cell (IT-SOFC) with samarium doped ceria (SDC) electrolyte. LSZF cathode at x = 0.2 composition demonstrates the remarkable electrochemical activity at intermediate temperature (550 °C): such as, high electrical conductivity (13.63 S cm−1), excellent thermal stability with SDC electrolyte (12.10 μK−1), high surface area (4.52 m2 g−1), extremely reduced area specific resistance (0.69 Ω cm−2) and low activation energy (0.117 eV). Furthermore, single fuel cells are fabricated using LSZF as a cathode, which exhibits the excellent performance by achieving the high power density of 409 mW cm−2 under natural gas as a fuel and ambient air as an oxidant at 550 °C with good stability over 10 h. All experimental results indicate that the LSZF is a promising cathode material for natural gas based intermediate temperature fuel cell applications.Download high-res image (267KB)Download full-size imageLSZF perovskite oxides demonstrate excellent electrochemical activity by achieving the high electrical conductivity and ultra-low area specific resistance at 550 °C. Furthermore, single fuel cell with LSZF cathode exhibits the outstanding electrochemical performance by achieving the high power density of 409 mW cm−2 with commercial available natural gas at 550 °C.
Co-reporter:Mingjun Wang, Xuefen Song, Bo Song, Jianlin Liu, Chenguo Hu, Dapeng Wei, Ching-Ping Wong
Sensors and Actuators B: Chemical 2017 Volume 250(Volume 250) pp:
Publication Date(Web):1 October 2017
DOI:10.1016/j.snb.2017.04.125
•Simple in situ growth of Cu2O nanoparticles on a G3DN.•The quantity of Cu2O grown on the G3DN is precisely controlled.•The in situ growth lead to a robust interface between Cu2O and G3DN.•Preeminent analytical performance for glucose detection.•The method to prepare electrode can be expanded to other electrochemical sensors.Due to the fact that catalytic oxidation of glucose only takes place on the surface of catalysts, increasing the specific surface of catalysts is an effective way to achieve high catalytic performance. Herein, we have developed an effective and extremely simple method to prepare a highly sensitive and enzyme-free glucose sensor with precisely quantified catalyst, which is prepared by in situ growth of Cu2O nanoparticles on a hierarchical graphene 3D network grown on carbon paper (G3DN/CP). The sensitivity, detection limit, response time and linear range of the sensor are (2.31 ± 0.03) × 103 μA mM−1 cm−2, 0.14 ± 0.01 μM, 1.6 s and 0.48–1813 μM, respectively. In addition, the sensor can retain 95.5% of its initial sensitivity even after 10 days. Specifically, due to the precise quantification of Cu2O nanoparticles deposited on G3DN, it is beneficial to mass production and precisely controlling the performance of the glucose sensor devices for public healthcare and industry. This approach could be used for other electrochemical sensors.The Cu2O/G3DN/CP electrode with precise quantification of Cu2O loading is fabricated by in situ growth and exhibits excellent analytical performance for glucose detection due to the high electrical conduction, large specific surface and fast electron transmission channels of G3DN, high catalytic capability of Cu2O nanoparticles, and the robust interface between Cu2O and G3DN.Download high-res image (162KB)Download full-size image
Co-reporter:Jianlin Liu, Cuiling Zhang, Biao Ma, Tiao Yang, Xiao Gu, Xue Wang, Junsheng Zhang, Chenguo Hu
Nano Energy 2017 Volume 38(Volume 38) pp:
Publication Date(Web):1 August 2017
DOI:10.1016/j.nanoen.2017.05.052
•A novel photocatalyst is designed in consideration of heterojunction band matching and surface plasmon resonance.•TiO2 and Ag work as a light harvester and an electron transfer media, and SrSO4 is used as electron trapping site.•A directed photoelectron flow path as ECB(TiO2)→Ef(Ag)→ECB(SrSO4) is obtained.•The TiO2/Ag/SrSO4 catalyst achieves highly efficient photocatalysis for degradation of MB or H2 evolution.Although photocatalysts are enormously explored for solar energy utilization, it remains a challenge to construct a highly efficient photocatalytic system by successfully steering the charge separation, transportation and consumption. Here we designed a novel photocatalyst by rationally constructing the photoelectron-trapped/accumulated site and electron transportation path via assembling TiO2, Ag and SrSO4 nanoparticle together, where TiO2 nanoparticles work as a solar energy harvester to generate electron-hole pairs, Ag nanoparticles conduct as electrons trapped and accumulated sites, and SrSO4 nanoparticles are used to build coherent electron transportation paths and consumption sites. Our work provides a general bottom-up route for designing and preparing novel photocatalysts with ultrafast charge separation and highly catalytic activates.Download high-res image (264KB)Download full-size image
Co-reporter:Qipeng Liu;Muhammad Sufyan Javed;Cuilin Zhang;Yanrong Li;Chengshuang Zhang;Meihui Lai;Qi Yang
Nanoscale (2009-Present) 2017 vol. 9(Issue 17) pp:5509-5516
Publication Date(Web):2017/05/04
DOI:10.1039/C6NR09959A
LiCoO2 (LCO) usually can deliver high energy density but low power density in Li-ion batteries (LIBs). Whether LCO could be used as electrode material for high-performance supercapacitors is dependent on promoting its power density. Owing to Faradaic redox reactions taking place on its surfaces or inside crystals through ion intercalation/deintercalation from the surfaces, increasing the specific area of LCO is a key factor to promote its rate capability. Herein, we report a facile strategy to prepare LCO nano-flakes with high specific area exceeding that of currently used micro-scale particles in LIBs. LCO as a nano-flake structure is expected to have a high fraction of Li atom exposure, which benefits fast redox reactions taking place on the surfaces. An LCO-based electrode exhibits an excellent specific capacitance of 581.3 F g−1 at 0.5 A g−1, high power density of 2262 W kg−1 at an energy density of 41.0 Wh kg−1, and good cycling stability (83.9% capacitance retention at 6 A g−1 after 2000 cycles) in LiCl aqueous electrolyte. Faradaic redox behaviors have been analyzed, indicating an ideal diffusion-controlled process. Moreover, a full solid-state symmetric supercapacitor is assembled using LCO nano-flake-based electrodes, which presents good performance with light weight and flexibility. Impressively, three charged supercapacitors in series can light 100 green light emitting diodes for 14 min. LCO in nano-flake structure form with high power density could be an excellent material for superior supercapacitors.
Co-reporter:Muhammad Sufyan Javed, Cuiling Zhang, Lin Chen, Yi Xi and Chenguo Hu
Journal of Materials Chemistry A 2016 vol. 4(Issue 22) pp:8851-8859
Publication Date(Web):09 May 2016
DOI:10.1039/C6TA01893A
Binary metal oxides have been considered as promising electrode materials for high performance pseudocapacitors because they offer higher electrochemical activity than mono metal oxides. The rational design of binder free electrode architecture is an efficient solution to the further enhancement of the performance of electrochemical supercapacitors. Herein, we report the synthesis of a hierarchical mesoporous NiFe2O4 (NFO) nanocone forest directly growing on carbon textile with ultra-high surface area by the hydrothermal method. The NiFe2O4 nanocone forest on carbon textile (NFO-CT) was used as a binder free electrode that exhibited the high capacitance of 697 F g−1 at a scan rate of 5 mV s−1 and was further used for the fabrication of a symmetric solid state supercapacitor. The open space between hierarchical nanocones allows easy diffusion for electrolyte ions and the carbon textile ensures fast electron transfer that leads to the remarkable electrochemical performance. The NFO-CT solid state supercapacitor exhibited the high capacitance of 584 F g−1 at a scan rate of 5 mV s−1 and 93.57% capacitance retention after 10000 cycles with the advantages of being light weight, thin and having good flexibility. A high energy density of 54.9 W h kg−1 at a power density of 300 W kg−1 was achieved, indicating the excellent energy storage features. Furthermore, three charged supercapacitors in series can light 4 red colored LEDs (2 V, 15 mA) for 2 min.
Co-reporter:Muhammad Sufyan Javed, Jie Chen, Lin Chen, Yi Xi, Cuilin Zhang, Buyong Wan and Chenguo Hu
Journal of Materials Chemistry A 2016 vol. 4(Issue 2) pp:667-674
Publication Date(Web):27 Nov 2015
DOI:10.1039/C5TA08752J
Nowadays, it is essential for us to design and fabricate efficient and cost-effective electrode materials for energy conversion and storage systems. Nanostructures are remarkable electrode materials due to their high surface area and large number of active sites. Herein zinc sulfide (ZnS) nanospheres with large surface area are hydrothermally grown on a flexible carbon textile (CT). The specific area and porosity are analyzed in detail under different pressures. The electrode based on the ZnS assembled CT (ZnS-CT) exhibits a high capacitance of 747 F g−1 at a scan rate of 5 mV s−1 in the LiCl aqueous electrolyte. The ZnS-CT is directly used as the binder free electrode for the fabrication of the symmetric flexible full solid state supercapacitor. The ZnS-CT supercapacitor shows excellent electrochemical performance along with light weight, thinness and good flexibility. The ZnS-CT supercapacitor demonstrates good capacitive behavior with a high specific capacitance of 540 F g−1 (areal capacitance of 56.25 F cm−2) at a scan rate of 5 mV s−1 with good rate capability and excellent cycling stability (94.6% retention of initial capacitance after 5000 cycles) at a constant current density of 0.8 mA cm−2. A high energy density of 51 W h kg−1 at a power density of 205 W kg−1 is achieved, indicating excellent ion accessibility and charge storage ability. Furthermore, three charged supercapacitors connected in series can light 4 red color light emitting diodes (2.0 V, 15 mA) for 2 min. ZnS nanospheres with large specific surface area combined with flexible carbon textile substrate offer to be a promising material in energy storage devices with high energy.
Co-reporter:Jie Chen, Hengyu Guo, Xianming He, Guanlin Liu, Yi Xi, Haofei Shi, and Chenguo Hu
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 1) pp:736
Publication Date(Web):December 14, 2015
DOI:10.1021/acsami.5b09907
Understanding of the triboelectric charge accumulation from the view of materials plays a critical role in enhancing the output performance of triboelectric nanogenerator (TENG). In this paper, we have designed a feasible approach to modify the tribo-material of TENG by filling it with high permittivity nanoparticles and forming pores. The influence of dielectricity and porosity on the output performance is discussed experimentally and theoretically, which indicates that both the surface charge density and the charge transfer quantity have a close relationship with the relative permittivity and porosity of the tribo-material. A high output performance TENG based on a composite sponge PDMS film (CS-TENG) is fabricated by optimizing both the dielectric properties and the porosity of the tribo-material. With the combination of the enhancement of permittivity and production of pores in the PDMS film, the charge density of ∼19 nC cm–2, open-circuit voltage of 338 V, and power density of 6.47 W m–2 are obtained at working frequency of 2.5 Hz with the optimized film consisting of 10% SrTiO3 nanoparticles (∼100 nm in size) and 15% pores in volume, which gives over 5-fold power enhancement compared with the nanogenerator based on the pure PDMS film. This work gives a better understanding of the triboelectricity produced by the TENG from the view of materials and provides a new and effective way to enhance the performance of TENG from the material itself, not just its surface modification.Keywords: charge density; dielectricity; nanogenerator; porosity; triboelectricity
Co-reporter:Muhammad Sufyan Javed, Xiangyu Han, Chenguo Hu, Meijuan Zhou, Zhiwei Huang, Xingfu Tang, and Xiao Gu
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 37) pp:24621
Publication Date(Web):August 25, 2016
DOI:10.1021/acsami.6b07924
Transition metal chalcogenides have emerged as a new class of electrode materials for energy storage devices with superior electrochemical performance. We have directly synthesized manganese sulfide nanoparticles on carbon textile substrate and used them as electrodes to fabricate flexible all-solid-state supercapacitors. By voltammetry analysis, we have studied the electrochemical properties of MnS-CT composites, which reveal that the Faradaic diffusion-controlled process dominates at low scan rates (82.85% at 5 mV s–1) and even at high scan rates (39% at 20 mV s–1). The MnS-CT electrode shows high capacitance of 710.6 F g–1 in LiCl aqueous electrolyte, and the surface redox reactions on MnS nanoparticles are found to be responsible for the high pseudocapacity, which is further analyzed by XRD and HRTEM. Furthermore, MnS-CT supercapacitor exhibits excellent pseudocapacitive performance (465 Fg–1 at 5 mV s–1), excellent stability, light weight (0.83 g as a whole device), and high flexibility. The device has also achieved high energy density and high power density (52 Wh kg–1 at 308 W kg–1 and 1233 W kg–1 with 28 Wh kg–1, respectively). In practice, three charged supercapacitors in series can power four red light-emitting diodes (LEDs) (2.0 V, 15 mA) for 2 min. All of the evidence shows that MnS nanoparticles combined with carbon textile is a promising electrode material for pseudocapacitors.Keywords: carbon textile; Faradaic process; Li+ intercalation; nanoparticles; pseudocapacitance
Co-reporter:Weina Xu, Jianlin Liu, Mingjun Wang, Lin Chen, Xue Wang, Chenguo Hu
Analytica Chimica Acta 2016 Volume 913() pp:128-136
Publication Date(Web):24 March 2016
DOI:10.1016/j.aca.2016.01.055
•The MnOOH nanorod arrays growing on carbon cloth (MnOOH/CC) are firstly fabricated by one-step hydrothermal route.•The MnOOH/CC serves as a high efficiency flexible electrode for non-enzymatic H2O2 biosensor.•The MnOOH/CC electrode exhibits superior sensitivity of 692.42 μA mM−1 cm−2 for the H2O2 detecting.Novel MnOOH nanorod arrays directly growing on a flexible carbon cloth substrate (MnOOH/CC) is first synthesized through a facile hydrothermal technique and utilized as an electrocatalyst for non-enzymatic detection of hydrogen peroxide. The as-prepared MnOOH nanorods are uniformly distributed on the carbon cloth with a 3D porous network structure, which provides a high specific surface area and numerous electroactive sites. The electrode based on the carbon cloth-supported MnOOH nanorod arrays exhibits a higher sensitivity (692.42 μA mM−1 cm−2) and a wider linear range (20 μm–9.67 mM) with a detection limit of 3.2 μM (S/N = 3) compared with the electrode based on the rigid graphite substrate supported the random distributed MnOOH nanorods. Further, the MnOOH/CC possesses an outstanding flexibility and can conveniently be assembled into the required shape for a specific use, thus the arc-shaped MnOOH/CC electrodes are fabricated whose electrocatalytic activity toward the hydrogen peroxide reduction remains nearly unchanged in comparison with the unbent state. Due to its excellent sensitivity, reproducibility, anti-interference and stability, the electrode based on the carbon cloth-supported MnOOH nanorod arrays is believed to be promising for applications in high efficiency flexible hydrogen peroxide sensing.
Co-reporter:Weina Xu, Shuge Dai, Guanlin Liu, Yi Xi, Chenguo Hu, Xue Wang
Electrochimica Acta 2016 Volume 203() pp:1-8
Publication Date(Web):10 June 2016
DOI:10.1016/j.electacta.2016.03.170
•The electrodes are fabricated by cupric oxide growing on carbon fiber fabric (CuO/CFF).•The capacitor performance is optimized by the mass loading.•One of the best electrochemical performances is achieved for CuO/CFF supercapacitor.•A highly flexible solid-state supercapacitor can power 3 light-emitting diodes for about 5 min.A hierarchical CuO nano-structure is prepared by directly growing CuO nanoflowers on carbon fiber fabric (CuO/CFF) via a hydrothermal method. The CuO/CFF is used as the electrode material of a supercapacitor for electrochemical energy storage. The supercapacitor displays superior electrochemical performance in aqueous electrolyte with the specific capacitance of 839.9 F/g at the scan rate of 1 mV/s, energy density of 10.05 Wh/kg and power density of 1798.5 W/kg, which are the highest values for the CuO/CFF electrodes. Moreover, a flexible symmetric solid-state symmetric supercapacitor is also fabricated by using the CuO/CFF as electrodes. The solid-state supercapacitor exhibits a specific capacitance of 131.34 F/g at the scan rate of 1 mV/s with a power density of 145.12 W/kg, and 95.8% capacitance retention after 2000 charge-discharge cycles.One of the best electrochemical performances for CuOelectrodes based supercapacitorisachieved by the CuOhierarchical structure growing on the carbon fiber fabric (CuO/CFF) in aqueous electrolyte. Meanwhile, a flexible solid-state supercapacitoris also fabricated as a promising candidate in energy storage for flexible, wearable and lightweight electronics.
Co-reporter:Muhammad Sufyan Javed, Zhiqiang Jiang, Cuiling Zhang, Lin Chen, Chenguo Hu, Xiao Gu
Electrochimica Acta 2016 Volume 219() pp:742-750
Publication Date(Web):20 November 2016
DOI:10.1016/j.electacta.2016.10.060
•FeS2 nanospheres assembled by nanoparticles provide large specific area and easy ion transmission paths.•First principles calculations are performed to investigate the diffusion mechanism of lithium ions in FeS2.•FeS2 network structure of the octahedrons and tunnels along c direction could benefit to ion intercalation.•A flexible solid state supercapacitor based on FeS2 nanospheres shows highly capacitive behavior.•Three charged supercapacitors connected in series can light 12 green color LED’s for 5.5 min.A flexible solid-state supercapacitor based on iron sulfide (FeS2) nanospheres supported on carbon-paper is fabricated, which exhibits excellent electrochemical performance such as, high capacitance of 484 F g−1 at a scan rate of 5 m Vs−1, good rate capability, and excellent cycling stability (95.7% after 5000 cycles). The supercapacitor achieves high energy density of 44 Wh kg−1 at power density of 175 W kg−1 with high coulombic efficiency (97%). Three charged supercapacitors connected in series can power 12 green-color light-emitting-diodes (LED, 3.0 V, 20 mA) for 5.5 minutes. To understand the detailed electrochemistry, we have carried out both experimental and theoretical investigations. The pseudocapacitive characteristics of the FeS2 nanospheres are systematically investigated by a single electrode in aqueous electrolyte. According to our structural analysis, the FeS2 nanospheres have orthorhombic structure, where Fe atoms are surrounded by 6 S atoms to form a FeS6 octahedron. These octahedrons are connected to form a network structure, which provide tunnels (2.55 × 4.77 Å). With all the evidence, we believe that the FeS2 nanospheres could be a promising material for supercapacitor electrodes.The nanoparticle-aggregation spheres offer large specific area and easy ion diffusion paths, which greatly enhances the active sites for redox reaction on the surface. FeS2 network structure of the octahedrons with tunnels along c direction could provide diffusion paths for the Li+ ion intercalation/de-intercalation during the charging/discharging process.
Co-reporter:Mingjun Wang, Xuefen Song, Shuge Dai, Weina Xu, Qi Yang, Jianlin Liu, Chenguo Hu, Dapeng Wei
Electrochimica Acta 2016 Volume 214() pp:68-75
Publication Date(Web):1 October 2016
DOI:10.1016/j.electacta.2016.08.036
Owing to the faradaic oxidation and reduction reactions mainly taking place on surface, enlarging the specific surface of redox materials is one of the most effective ways to achieve excellent electrochemical performance. Here we report a binder-free three dimensional (3D) architecture electrode consisting of a graphene 3D network (G3DN) structure growing on flexible carbon paper (CP) by chemical vapor deposition and NiO nanoparticles growing on the G3DN by in-situ thermal decomposition for high rate battery and high-performance electrochemical capacitors. Such a nanostructure provides a large specific surface and fast electronic transmission channels. The unique structure design for this electrode enables outstanding performance, showing high specific capacity of 89.1 mAh cm−2 (119.2 mAh/g) at current density of 0.5 mA cm−2 (0.67 A/g) with the NiO loading of 0.7471 mg cm−2. Meanwhile the electrode displays excellent rate capability and cycling stability, which keeps 85.48% of initial capacity after 3000 deep-discharge cycles. Furthermore, a solid-state symmetric electrochemical capacitor based on two NiO/G3DN/CP electrodes with an area of 4 cm2 each is fabricated, and two pieces of them in series can light up 100 green LEDs for 2 min. The architecture of G3DN loaded with NiO might be generally applied to different kinds of nanomaterials for high-rate energy storage to improve their overall electrochemical performance.
Co-reporter:Muhammad Sufyan Javed, Rizwan Raza, Zishan Ahsan, M. Shahid Rafique, Shamaila Shahzadi, S.F. Shaukat, Nusrat Shaheen, Muhammad Saeed Khalid, Hu Chengou, Bin Zhu
International Journal of Hydrogen Energy 2016 Volume 41(Issue 4) pp:3072-3078
Publication Date(Web):30 January 2016
DOI:10.1016/j.ijhydene.2015.11.144
•The perovskite cathode material for low temperature SOFC fueled by natural gas.•The average crystalline size are 28 nm –36 nm at x = 0.25 and 0.30 respectively.•TGA showed the lattice oxygen loss of YSFT is about 0.206 %.•The maximum conductivities of 2.3 Scm−1 and 2.07 Scm−1 were achieved.•The fuel cell device has demonstrated very stable results with natural gas.Natural gas is the most promising renewable energy source and its widespread availability ensured its importance for early applications in stationary fuel cells as a reliable and low cost fuel. Therefore it is very important to efficiently utilization of natural gas in low temperature fuel cells. Herein, we demonstrate the synthesis of perovskite material of Yttrium doped Sr0.92FexTi1-xO3-δ (x = 0.25, 0.30) (YSFT) by solid state reaction method and further investigated as a new cathode material for a low temperature solid oxide fuel cell fueled by natural gas. The YSFT is characterized by X-ray powder diffraction, Brunauer–Emmett–Teller and scanning electron microscopy. The perovskite structure is achieved at relatively low temperature (850 °C). The average crystalline size is found 28 nm and 36 nm for x = 0.25 and 0.30 respectively. TGA results showed the lattice oxygen loss of YSFT is about 0.206% in its original weight in the temperature range of 25–1000 °C. The maximum electronic conductivities of 2.3 Scm−1 and 2.07 Scm−1 are achieved for x = 0.25 and x = 0.30 at 550 °C in air atmosphere respectively. It is observed that the oxygen reduction is enhanced due to the perovskite crystal structure and oxygen vacancies play an important role in the redox reaction to improve the performance of fuel cell. The YSFT perovskite cathode material based fuel cell with natural gas have achieved the power density of 250 mWcm−2 for x = 0.25 at 550 °C. The fuel cell device has demonstrated very stable results by running continuously for 5 h with domestic available natural gas.
Co-reporter:Jie Chen, Hengyu Guo, Jiangeng Zheng, Yingzhou Huang, Guanlin Liu, Chenguo Hu, and Zhong Lin Wang
ACS Nano 2016 Volume 10(Issue 8) pp:8104
Publication Date(Web):August 4, 2016
DOI:10.1021/acsnano.6b04440
Liquid and gas flow sensors are important components of the micro total analysis systems (μTAS) for modern analytical sciences. In this paper, we proposed a self-powered triboelectric microfluidic sensor (TMS) by utilizing the signals produced from the droplet/bubble via the capillary and the triboelectrification effects on the liquid/solid interface for real-time liquid and gas flow detection. By alternating capillary with different diameters, the sensor’s detecting range and sensitivity can be adjusted. Both the relationship between the droplet/bubble and capillary size, and the output signal of the sensor are systematically studied. By demonstrating the monitoring of the transfusion process for a patient and the gas flow produced from an injector, it shows that TMS has a great potential in building a self-powered micro total analysis system.Keywords: microfluidic sensor; self-powered system; triboelectric
Co-reporter:Hengyu Guo, Min-Hsin Yeh, Ying-Chih Lai, Yunlong Zi, Changsheng Wu, Zhen Wen, Chenguo Hu, and Zhong Lin Wang
ACS Nano 2016 Volume 10(Issue 11) pp:10580
Publication Date(Web):November 7, 2016
DOI:10.1021/acsnano.6b06621
Recently, a self-charging power unit consisting of an energy harvesting device and an energy storage device set the foundation for building a self-powered wearable system. However, the flexibility of the power unit working under extremely complex deformations (e.g., stretching, twisting, and bending) becomes a key issue. Here, we present a prototype of an all-in-one shape-adaptive self-charging power unit that can be used for scavenging random body motion energy under complex mechanical deformations and then directly storing it in a supercapacitor unit to build up a self-powered system for wearable electronics. A kirigami paper based supercapacitor (KP-SC) was designed to work as the flexible energy storage device (stretchability up to 215%). An ultrastretchable and shape-adaptive silicone rubber triboelectric nanogenerator (SR-TENG) was utilized as the flexible energy harvesting device. By combining them with a rectifier, a stretchable, twistable, and bendable, self-charging power package was achieved for sustainably driving wearable electronics. This work provides a potential platform for the flexible self-powered systems.Keywords: kirigami; self-charging power package; supercapacitors; triboelectric nanogenerators; wearable electronics
Co-reporter:Cuiling Zhang
The Journal of Physical Chemistry C 2016 Volume 120(Issue 22) pp:12218-12225
Publication Date(Web):May 20, 2016
DOI:10.1021/acs.jpcc.6b04145
Tungstates are important photoluminescence (PL) materials owing to their unique luminescence center. However, radiative or nonradiative recombination affected by defects and electron-phone coupling have not been well understood. In this paper, we have synthesized CdWO4 nanorods and studied its temperature-dependent PL spectrum from 20 to 300 K. Theoretical calculations demonstrate that Cd vacancy (VCd) and O vacancies (VO0, VO1+, and VO2+) induce extra levels in the band gap, by which the VCd, VO0, and VO1+ defects mainly contribute to the absorption in 0–4 eV region, while VO2+ causes the emission bands peaked at 490 nm in PL spectrum. Because of the broken symmetry of octahedron two possible types of lowest unoccupied molecular orbital (LUMO) appear and the transitions from the each LUMO to the highest occupied molecular orbital (HOMO) contribute to the emission at about 410 and 436 nm. The emission intensity of the peaks decreases with an increase in temperature due to the thermal quenching by nonradiative recombination. This work insights into the understanding of physical nature of emission and presents a detailed analysis of the electron transition behaviors in the wolframite-type monoclinic CdWO4, which can be used not only to explain the photoluminescence mechanism of CdWO4, but also for the structure design to obtain better emission properties in tungstates.
Co-reporter:Xianming He;Xiaojing Mu;Quan Wen;Zhiyu Wen;Jun Yang
Nano Research 2016 Volume 9( Issue 12) pp:3714-3724
Publication Date(Web):2016 December
DOI:10.1007/s12274-016-1242-3
A flexible and transparent triboelectric nanogenerator (FT-TENG) has great potential for application in self-powered biosensor systems, electronic skin and wearable electronic devices. However, improving the output performance with little damage to its optical properties is challenging. Herein, we have developed an FT-TENG that has a well-ordered nest-like porous polydimethylsiloxane (NP-PDMS) film and graphene transparent electrodes. The NP-PDMS film with ordered pores is fabricated by hydrochloric acid etching of 500 nm sized ZnO spheres made of aggregated nanoparticles, having a light transmittance of 81.8% and a water contact angle of 118.62°. The FT-TENG based on the NP-PDMS film with a porosity of 12%, gives a maximum output of 271 V and 7.8 μA, which are respectively, 3.7 and 2.1-fold of those of a TENG with a flat PDMS film. The peak output power reaches 0.39 mW with a load resistance of 9.01 MΩ. The dielectric constant and effective thickness of the NP-PDMS film and the capacitance and charge transfer of the FT-TENG are systematically investigated. This work provides a novel and effective method to enhance the performance of FT-TENGs with little damage to their optical properties.
Co-reporter:Guanlin Liu;Hengyu Guo;Lin Chen;Xue Wang;Dapeng Wei
Nano Research 2016 Volume 9( Issue 11) pp:3355-3363
Publication Date(Web):2016 November
DOI:10.1007/s12274-016-1213-8
Integrated multilayered triboelectric nanogenerators (TENGs) are an efficient approach to solve the insufficient energy problem caused by a single-layered TENG for achieving high output power density. However, most integrated multilayered TENGs have a relatively large volume. Here, a double-induced-mode integrated triboelectric nanogenerator (DI-TENG) based on spring steel plates is presented as a cost-effective, simple, and high-performance device for ambient vibration energy harvesting. The unique stackable rhombus structure, in which spring steel plates act both as skeletons and as electrodes, can enhance the output performance and maximize space utilization. The DI-TENG with five repeated units in a volume of 12 cm × 5 cm × 0.4 cm can generate a short-circuit current of 51 μA and can transfer charges of 1.25 μC in a half period. The contrast experiment is conducted systematically and the results have proved that the DI-TENG has a great advantage over the single-induced-mode TENG (SI-TENG) with only one side of a friction layer on its electrode. Besides, the DI-TENG can easily power a commercial calculator and can be used as a door switch sensor.
Co-reporter:Yue Kang;Qiang Leng;Donglin Guo;Dezhi Yang;Yanping Pu
Nano-Micro Letters 2016 Volume 8( Issue 1) pp:13-19
Publication Date(Web):2016 January
DOI:10.1007/s40820-015-0056-2
Ceria (CeO2) nanocubes were synthesized by a hydrothermal method and weak ferromagnetism was observed in room temperature. After ultraviolet irradiation, the saturation magnetization was significantly enhanced from ~3.18 × 10−3 to ~1.89 × 10−2 emu g−1. This is due to the increase of oxygen vacancies in CeO2 structure which was confirmed by X-ray photoelectron spectra. The first-principle calculation with Vienna ab-initio simulation package was used to illustrate the enhanced ferromagnetism mechanism after calculating the density of states (DOSs) and partial density of states (PDOSs) of CeO2 without and with different oxygen vacancies. It was found that the increase of oxygen vacancies will enlarge the PDOSs of Ce 4f orbital and DOSs. Two electrons in one oxygen vacancy are respectively excited to 4f orbital of two Ce atoms neighboring the vacancy, making these electron spin directions on 4f orbitals of these two Ce atoms parallel. This superexchange interaction leads to the formation of ferromagnetism in CeO2 at room temperature. Our work indicates that ultraviolet irradiation is an effective method to enhance the magnetism of CeO2 nanocube, and the first-principle calculation can understand well the enhanced magnetism.
Co-reporter:Guanlin Liu;Renping Liu;Hengyu Guo;Yi Xi;Dapeng Wei
Advanced Electronic Materials 2016 Volume 2( Issue 5) pp:
Publication Date(Web):
DOI:10.1002/aelm.201500448
A waterwheel-like electrode combined with a spring steel plate is used to construct a novel triboelectric generator (WSTG) for efficient harvesting of low-velocity rotational motion energy. By utilizing a spring steel plate, the energy of a low-speed rotational motion is first transformed into elastic potential energy through elastic deformation stored in the device, and then the elastic potential energy is released into kinetic energy of high-speed motion. Thus, a high output current is obtained. With its unique five-blade, waterwheel-like structure, each of the electrodes can fully contact the polymer friction layer during the rotation process. The WSTG achieves a maximum current, voltage, and power density of 102 μA, 612 V, and 3.12 W m−2, respectively, in low-speed rotating motion. The working mechanism, robustness, and other factors that may affect the output performance are systematically studied. Moreover, a rotating speed and rotational angle sensor based on this WSTG is fabricated. The advantages of such WSTG working at low-speed rotational motion with high efficiency provide great potential applications in ambient energy harvesting.
Co-reporter:Shuge Dai, Weina Xu, Yi Xi, Mingjun Wang, Xiao Gu, Donglin Guo, Chenguo Hu
Nano Energy 2016 Volume 19() pp:363-372
Publication Date(Web):January 2016
DOI:10.1016/j.nanoen.2015.11.025
•KCu7S4 with unique double-tunnel structure and excellent conductivity exhibits outstanding electrochemical properties.•The diffusion paths of K+, Li+ and H+ in the KCu7S4 tunnels are reported based on the theoretical analysis.•A highly flexible all-solid-state supercapacitor is fabricated based on the KCu7S4/Graphene paper electrodes.Supercapacitors are promising devices for highly efficient energy storage and power management. A notable improvement in performance has been achieved through recent advances in understanding charge storage mechanism and the development of advanced nanostructured materials. Here, by combining experimental and theoretical investigations, we have unveiled the detailed charge storage mechanism of KCu7S4 wires based on a flexible all-solid-state supercapacitor. KCu7S4 with a unique double-tunnel structure and excellent conductivity exhibits outstanding properties as an electrode material in supercapacitors. Both electrochemical experiments and DFT calculations show that the stable energy storage process is mainly contributed by potassium ions׳ insertion/extraction, where potassium ions are proved to have been more active than lithium ions in the redox reactions on the KCu7S4 electrodes. The flexible supercapacitor based on the KCu7S4/Graphene paper is low-cost, easy to fabricate and environmentally friendly. The understanding for the charge storage presented in this work would guide the improvement on supercapacitor and exploration of new electrode materials.KCu7S4 with unique double-tunnel structure and excellent conductivity exhibits outstanding properties as a redox active material in supercapacitors. The diffusion paths of K+, Li+ and H+ in the KCu7S4 tunnels are reported based on the density functional theory, thermodynamic analysis and nudged elastic band method.
Co-reporter:Hengyu Guo;Qiang Leng;Xianming He;Mingjun Wang;Jie Chen;Yi Xi
Advanced Energy Materials 2015 Volume 5( Issue 1) pp:
Publication Date(Web):
DOI:10.1002/aenm.201400790
A triboelectric generator based on checker-like interdigital electrodes (TEGC) with a sandwiched polyethylene terephthalate (PET) thin film that can convert translation kinetic energy in all directions to electricity is reported. The design of the sandwiched PET thin film can effectively avoid direct wear between metal electrodes and sliding panel. The mechanism of the TEGC is described in detail. The performance of the TEGC in different sliding directions is studied, indicating a maximum output power density of 1.9 W m-2 and open-circuit voltage of 210 V achieved in the X or Y sliding direction. The TEGC is used to charge a 110 μF commercial capacitor to 5 V in 35 s and light up two light-emitting diodes (LEDs) connected with the capacitor simultaneously. The TEGC based mouse pad and sliding panel are fabricated to harvest mouse operation energy to light up LEDs connected in antiparallel when the computer mouse operates a game. The TEGC has advantages of being flexible, light weight, durable, cost effective, and portable by folding or rolling into a small part. This work presents a significant progress toward the structure design of triboelectric generator for its practical applications.
Co-reporter:Muhammad Sufyan Javed, Shuge Dai, Mingjun Wang, Yi Xi, Qiang Lang, Donglin Guo and Chenguo Hu
Nanoscale 2015 vol. 7(Issue 32) pp:13610-13618
Publication Date(Web):09 Jul 2015
DOI:10.1039/C5NR03363B
The exploration of high Faradic redox active materials with the advantages of low cost and low toxicity has been attracting great attention for producing high energy storage supercapacitors. Here, the high Faradic redox active material of Cu7S4-NWs coated on a carbon fiber fabric (CFF) is directly used as a binder-free electrode for a high performance flexible solid state supercapacitor. The Cu7S4-NW-CFF supercapacitor exhibits excellent electrochemical performance such as a high specific capacitance of 400 F g−1 at the scan rate of 10 mV s−1 and a high energy density of 35 Wh kg−1 at a power density of 200 W kg−1, with the advantages of a light weight, high flexibility and long term cycling stability by retaining 95% after 5000 charge–discharge cycles at a constant current of 10 mA. The high Faradic redox activity and high conductance behavior of the Cu7S4-NWs result in a high pseudocapacitive performance with a relatively high specific energy and specific power. Such a new type of pseudocapacitive material of Cu7S4-NWs with its low cost is very promising for actual application in supercapacitors.
Co-reporter:Xianming He, Hengyu Guo, Xule Yue, Jun Gao, Yi Xi and Chenguo Hu
Nanoscale 2015 vol. 7(Issue 5) pp:1896-1903
Publication Date(Web):03 Dec 2014
DOI:10.1039/C4NR05512H
Nanogenerators with capacitor structures based on piezoelectricity, pyroelectricity, triboelectricity and electrostatic induction have been extensively investigated. Although the electron flow on electrodes is well understood, the maximum efficiency-dependent structure design is not clearly known. In this paper, a clear understanding of triboelectric generators with capacitor structures is presented by the investigation of polydimethylsiloxane-based composite film nanogenerators, indicating that the generator, in fact, acts as both an energy storage and output device. Maximum energy storage and output depend on the maximum charge density on the dielectric polymer surface, which is determined by the capacitance of the device. The effective thickness of polydimethylsiloxane can be greatly reduced by mixing a suitable amount of conductive nanoparticles into the polymer, through which the charge density on the polymer surface can be greatly increased. This finding can be applied to all the triboelectric nanogenerators with capacitor structures, and it provides an important guide to the structural design for nanogenerators. It is demonstrated that graphite particles with sizes of 20–40 nm and 3.0% mass mixed into the polydimethylsiloxane can reduce 34.68% of the effective thickness of the dielectric film and increase the surface charges by 111.27% on the dielectric film. The output power density of the triboelectric nanogenerator with the composite polydimethylsiloxane film is 3.7 W m−2, which is 2.6 times as much as that of the pure polydimethylsiloxane film.
Co-reporter:Guanlin Liu, Weina Xu, Xiaona Xia, Haofei Shi and Chenguo Hu
Journal of Materials Chemistry A 2015 vol. 3(Issue 42) pp:21133-21139
Publication Date(Web):08 Sep 2015
DOI:10.1039/C5TA06438D
Triboelectric nanogenerators (TENG) that harvest energy from ambient environment have attracted great attention since they were first reported. However, the structures of TENGs working in the vertical contact-separation mode are considerably monotonous and energy loss cannot be avoided during the working process. In this study, we design a novel TENG, which is based on three elastic plates and one acryl board in the center with two identical steel plates on both sides, using which periodic contact/separation of the friction layers proceeds like Newton's cradle, except for the intermittent input of mechanical energy to overcome the electrostatic interaction on the charged friction layers. Such a lamination structure in the original contact mode can provide considerably higher energy conversion efficiency than that of the friction layers in the original separation mode. With this new design, the output current of the TENG is 5.7 times as much as that of a common contact/separation TENG and 2.3 times as much as that of a similar structure TENG without the use of elasticity. The maximum short-circuit current, open-circuit voltage and output power are 114 μA, 428 V, and 4.32 W m−2, respectively, which are strong enough to light more than one hundred commercial LED lights. In addition, the TENG was applied to a self-powered flashing clapping palm decorated by 29 LEDs, which might replace the fluorescence palms that are powered by the chemical reactions of a dye mixed solution, in the future.
Co-reporter:Weina Xu, Shuge Dai, Xue Wang, Xianming He, Mingjun Wang, Yi Xi and Chenguo Hu
Journal of Materials Chemistry A 2015 vol. 3(Issue 28) pp:5777-5785
Publication Date(Web):03 Jun 2015
DOI:10.1039/C5TB00592B
A novel and exceptionally sensitive glucose biosensor based on nanorod-aggregated flower-like CuO grown on a carbon fiber fabric (CFF) is developed for glucose detection, which is prepared by a simple, fast and green hydrothermal method. The electron transfer resistance of the CuO/CFF electrode on the interface between the electrode and the electrolyte is as low as 12.79 Ω as evaluated by electrochemical impedance spectroscopy. A cyclic voltammetry study reveals that the CuO/CFF electrode displays an excellent electrocatalytic activity toward the direct oxidation of glucose. Besides, chronoamperometry demonstrates a high sensitivity of 6476.0 μA mM−1 cm−2 at an applied potential of 0.45 V (vs. Ag/AgCl), with a fast response time and a low detection limit of only 1.3 s and ∼0.27 μM, respectively. In addition, the glucose sensor has high reproducibility with a relative standard deviation (R.S.D.) of 1.53% over eight identically fabricated electrodes and long-term stability with a minimal sensitivity loss of ∼9.9% over a period of one month as well as excellent anti-interference ability. Importantly, the CuO–CFF composite has such good flexible characteristics and can be fabricated into flexible electrodes for application in various complicated circumstances. This work presents a new strategy to achieve highly sensitive glucose sensors with flexibility by growing glucose electroactive nanostructure materials directly on multichannels and highly conductive carbon fiber fabrics.
Co-reporter:Guanlin Liu, Qiang Leng, Jiawei Lian, Hengyu Guo, Xi Yi, and Chenguo Hu
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 2) pp:1275
Publication Date(Web):January 7, 2015
DOI:10.1021/am507477y
Great attention has been paid to nanogenerators that harvest energy from ambient environments lately. In order to give considerable output current, most nanogenerators require high-velocity motion that in most cases can hardly be provided in our daily life. Here we report a notepad-like triboelectric generator (NTEG), which uses simple notepad-like structure to generate elastic deformation so as to turn a low-velocity kinetic energy into high-velocity kinetic energy through the conversion of elastic potential energy. Therefore, the NTEG can achieve high current output under low-velocity motion, which completely distinguishes it from tribogenerators previously reported. The factors that may affect the output performance are explored, including the number of slices, active length of slice, press speed, and vertical displacement. In addition, the working mechanism is systematically studied, indicating that the efficiency of the generator can be greatly enhanced by interconversion between kinetic energy and elastic potential energy. The short-circuit current, the open-circuit voltage, and power density are 205 μA and 470 V and 9.86 W/m2, respectively, which is powerful enough to light up hundreds of light-emitting diodes (LEDs) and charge a commercial capacitor. Besides, NTEGs have been successfully applied to a self-powered door monitor.Keywords: door monitor; elastic deformation; notepad-like structure; self power; triboelectric generator
Co-reporter:Lin Chen, Hengyu Guo, Xiaona Xia, Guanlin Liu, Haofei Shi, Mingjun Wang, Yi Xi, and Chenguo Hu
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 30) pp:16450
Publication Date(Web):July 7, 2015
DOI:10.1021/acsami.5b03613
A planar spiral-like electrodes (PSE) based triboelectric generator has been designed for harvesting rotary mechanical energy to translate into electricity. The performance of the PSE-triboelectric generator with different cycles of spiral-like electrode strip at different rotating speeds is investigated, which demonstrates the open-circuit voltage and short-circuit current of 470 V and 9.0 μA at rotating speed of 500 r/min with three cycles. In addition, a novel coaxially integrated multilayered PSE-triboelectric generator is built, which can enhance the output of the power effectively. The short-circuit current, the open-circuit voltage, and output power reach to 41.55 μA, 500 V, and 11.73 mW, respectively, at rotating speed of 700 r/min. The output power of the multilayered PSE-triboelectric generator can drive 200 LEDs connected in antiparallel and charge a 110 μF commercial capacitor to 6 V in 23 s. Besides, due to the spiral-like electrode structure, the PSE-generator can work simultaneously in the modes of triboelectricity and electromagnetic induced electricity by sticking a small magnet on the rotating disk. The electromagnetic induced output power reaches to 21 μW at a loading resistance of 2 Ω at a rotating rate of 200 r/min. The spiral-like electrode structure not only broadens the electrode structure design but also adds a new function to the electrode.Keywords: electromagnetic generator; multilayered; planar spiral-like electrode; rotary mechanical energy; triboelectric nanogenerator
Co-reporter:Yue Kang, Bo Wang, Shuge Dai, Guanlin Liu, Yanping Pu, and Chenguo Hu
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 36) pp:20469
Publication Date(Web):August 25, 2015
DOI:10.1021/acsami.5b06675
A folded elastic strip-based triboelectric nanogenerator (FS-TENG) made from two folded double-layer elastic strips of Al/PET and PTFE/PET can achieve multiple functions by low frequency mechanical motion. A single FS-TENG with strip width of 3 cm and length of 27 cm can generate a maximum output current, open-circuit voltage, and peak power of 55 μA, 840 V, and 7.33 mW at deformation frequency of 4 Hz with amplitude of 2.5 cm, respectively. This FS-TENG can work as a weight sensor due to its good elasticity. An integrated generator assembled by four FS-TENGs (IFS-TENG) can harvest the energy of human motion like flapping hands and walking steps. In addition, the IFS-TENG combined with electromagnetically induced electricity can achieve a completely self-driven doorbell with flashing lights. Moreover, a box-like generator integrated by four IFS-TENGs inside can work in horizontal or random motion modes and can be improved to harvest energy in all directions. This work promotes the research of completely self-driven systems and energy harvesting of human motion for applications in our daily life.Keywords: doorbell; folded elastic strip; human motion; nanogenerator; self-driven
Co-reporter:Muhammad Sufyan Javed, Shuge Dai, Mingjun Wang, Donglin Guo, Lin Chen, Xue Wang, Chenguo Hu, Yi Xi
Journal of Power Sources 2015 Volume 285() pp:63-69
Publication Date(Web):1 July 2015
DOI:10.1016/j.jpowsour.2015.03.079
•MoS2 hierarchical nanospheres are used for the first time to make supercapacitor on carbon cloth.•A flexible solid state supercapacitor based on MoS2 hierarchical nanospheres shows excellent electrochemical performance.•High specific capacitance of 368 Fg−1 at scan rate of 5 mVs−1 is achieved with long term cycling stability.•The flexible supercapacitor has almost same performance in different bending angles.Molybdenum sulfide (MoS2) hierarchical nanospheres are synthesized using a hydrothermal method and characterized by X-ray powder diffraction, Brunauer–Emmett–Teller, scanning electron microscopy and transmission electron microscopy. The prepared MoS2 is used to fabricate solid state flexible supercapacitors which show excellent electrochemical performance such as high capacitance 368 F g−1 at a scan rate of 5 mV s−1 and high power density of 128 W kg−1 at energy density of 5.42 Wh kg−1. The fabricated supercapacitor presents good characteristics such as lightweight, low cast, portability, high flexibility, and long term cycling stability by retaining 96.5% after 5000 cycles at constant discharge current of 0.8 mA. Electrochemical impedance spectroscopy (EIS) results reveal low resistance and suggest that MoS2 nanospheres would be a promising candidate for supercapacitors. Three charged supercapacitors connected in series can light 8 red color commercial light emitting diodes (LEDs) for 2 min, demonstrating its capability as a good storage device.A flexible solid state supercapacitor based on MoS2 hierarchical nanospheres shows excellent electrochemical performance and high specific capacitance of 368 Fg−1 at scan rate of 5 mVs−1 with long term cycling stability, demonstrating its capability as a good storage device.
Co-reporter:Weina Xu, Chunhua Zheng, Hao Hua, Qi Yang, Lin Chen, Yi Xi, Chenguo Hu
Applied Surface Science 2015 Volume 327() pp:140-148
Publication Date(Web):1 February 2015
DOI:10.1016/j.apsusc.2014.11.156
Highlights
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A facile CHM strategy is employed for the first time to synthesize CdWO4 nanowire and nanoflower arrays on cadmium foils.
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The photoelectrochemical (PEC) properties are measured on the electrodes made of the CdWO4 nanowire and nanoflower arrays.
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The photocurrent density of the nanowire electrode reaches 0.35 mA/cm2, which is 3 times as much as that of the nanoflower electrode.
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CdS nanoparticles are deposited on CdWO4 nanowire arrays to form a CdS/CdWO4 heterojunction to improve the PEC properties.
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The remarkably enhanced photoresponse is achieved on the CdS/CdWO4 which is twice as much as that on the pure CdWO4 electrode.
Co-reporter:Xuefen Song, Mingjun Wang, Dapeng Wei, Dun Liu, Haofei Shi, Chenguo Hu, Liang Fang, Wei Zhang, Chunlei Du
Journal of Alloys and Compounds 2015 Volume 651() pp:230-236
Publication Date(Web):5 December 2015
DOI:10.1016/j.jallcom.2015.08.096
•The GWs/CdS composites were synthesized via a simple SILAR process.•The mechanism of enhanced photocurrent response was investigated.•The GWs/CdS anode exhibits photo-current density of 470 μA/cm2.•The GWs/CdS anode has excellent stability.A photo-electrochemical electrode of CdS–modified graphene walls (GWs) is fabricated via a successive ionic layer adsorption and reaction (SILAR) process. The as-prepared CdS–GWs composite structures could notably enhance photon absorption (in the visible region) and effectively facilitate the spatial separation of photo-generated carriers, bringing the enhanced photocurrent response. The effective area between CdS nanoparticles (NPs) and GWs is a crucial factor for the photocurrent density. Remarkably, the proposed CdS–GWs photo-anode displays satisfactory performance with the excellent photo-current density of 470 μA/cm2 and wonderful stability as long as dozens of days. Our studies confirm that CdS–GWs nano-composites could work as high-performance photo-electrochemical electrodes for a lot of potential applications.
Co-reporter:Hengyu Guo, Jie Chen, Qiang Leng, Yi Xi, Mingjun Wang, Xianming He, Chenguo Hu
Nano Energy 2015 Volume 12() pp:626-635
Publication Date(Web):March 2015
DOI:10.1016/j.nanoen.2014.09.021
•We design and fabricate spiral interdigital electrodes based triboelectric generator (SETG).•The SETG is a dual-functional generator that can harvest both translational motion energy and rotational energy.•The SETG can be used as a dual-functional self-powered sensor for detecting rotating speed and momentum of a moving object.•This work presents an improvement toward a structure design of generator for its multifunctional applications.Spiral electrodes based triboelectric generator (SETG) is designed with double dual-functions. The novel spiral interdigital-electrodes makes the SETG have dual-function for harvesting rotational energy and translational motion energy. Meanwhile, the SETG can be used as a dual-functional sensor for detecting rotating speed and momentum of moving object. The SETG working mechanism and the output performance in rotational mode and axial translational modes are systematically investigated. Output power of ~7 mW, open-circuit voltage of ~400 V in rotational mode and power of ~1.5 mW, open-circuit voltage of ~350 V in axial translational mode are obtained, respectively, which can be used to light up 200 LEDs connected in antiparallel. In addition, SETG-based dual-functional sensor exhibits excellent advantages including self-power, high sensitivity, low cost, and easy fabrication. This work presents a significant progress toward a structure design of triboelectric generator for its multifunctional applications.
Co-reporter:Xiaona Xia, Guanlin Liu, Hengyu Guo, Qiang Leng, Chenguo Hu, Yi Xi
Nano Energy 2015 Volume 15() pp:766-775
Publication Date(Web):July 2015
DOI:10.1016/j.nanoen.2015.05.033
•Honeycomb-like three electrodes based triboelectric generator is designed for the first time.•The generator can harvest full space mechanical energy without off state.•The three electrodes can be used in a spherical shell as a football-like generator or vibration alertor.•The idea of multi-electrodes would be an effective strategy to achieve multi-functions in scavenging energy.A novel honeycomb-like triboelectric generator (HTEG) based on three electrodes has been designed for harvesting mechanical energy in full space. It has symmetric and periodic arrangement of the three electrodes in plane or on the inner surface of ball, which can harvest sliding energy along arbitrary direction without off state because each electrode is always surrounded by the electrodes different from itself. Meanwhile, the device can effectively scavenge ambient vibration energy as an independent generator in full space by working at both contact-separation mode and sliding mode without contacting with the ground. The maximum output current density, voltage and power density can reach 16.4 mA/m2, 413 V, and 2.1 W/m2, respectively, by working in plane sliding mode, and the maximum output current to be 0.55 μA by working in sliding mode on an inner surface of a spherical shell. The HTEG can charge a 100 μF commercial capacitor to 2.1 V in 80 s. The football-like HTEG is used as a vibration alertor, which could be applied in vibration monitor or geologic hazard alertor for bridges and buildings. The idea of multi-electrode in HTEGs would be an effective strategy to achieve multi-function in scavenging energy.A novel honeycomb-like three electrodes based triboelectric generator is designed and fabricated, which can harvest full space energy without any off state. The generator can be used as a self-powered vibration alertor with high sensitivity. The idea of multi-electrodes would be an effective strategy to achieve multi-functions in scavenging energy for triboelectric generators.
Co-reporter:Hengyu Guo, Jun Chen, Min-Hsin Yeh, Xing Fan, Zhen Wen, Zhaoling Li, Chenguo Hu, and Zhong Lin Wang
ACS Nano 2015 Volume 9(Issue 5) pp:5577
Publication Date(Web):May 12, 2015
DOI:10.1021/acsnano.5b01830
Harvesting ambient mechanical energy is a green route in obtaining clean and sustainable electric energy. Here, we report an ultrarobust high-performance triboelectric nanogenerator (TENG) on the basis of charge replenishment by creatively introducing a rod rolling friction in the structure design. With a grating number of 30 and a free-standing gap of 0.5 mm, the fabricated TENG can deliver an output power of 250 mW/m2 at a rotating rate of 1000 r/min. And it is capable of charging a 200 μF commercial capacitor to 120 V in 170 s, lighting up a G16 globe light as well as 16 spot lights connected in parallel. Moreover, the reported TENG holds an unprecedented robustness in harvesting rotational kinetic energy. After a continuous rotation of more than 14.4 million cycles, there is no observable electric output degradation. Given the superior output performance together with the unprecedented device robustness resulting from distinctive mechanism and novel structure design, the reported TENG renders an effective and sustainable technology for ambient mechanical energy harvesting. This work is a solid step in the development toward TENG-based self-sustained electronics and systems.Keywords: charge replenishment; rolling friction; ultrarobustness;
Co-reporter:Qiang Leng, Dezhi Yang, Qi Yang, Chenguo Hu, Yue Kang, Mingjun Wang, Muhammad Hashim
Materials Research Bulletin 2015 65() pp: 266-272
Publication Date(Web):
DOI:10.1016/j.materresbull.2015.02.008
Co-reporter:Chunlan Cao, Chenguo Hu, Weidong Shen, Shuxia Wang, Sihong Song, Mingjun Wang
Materials Research Bulletin 2015 70() pp: 155-162
Publication Date(Web):
DOI:10.1016/j.materresbull.2015.04.036
Co-reporter:Qiang Leng, Hengyu Guo, Xianming He, Guanlin Liu, Yue Kang, Chenguo Hu and Yi Xi
Journal of Materials Chemistry A 2014 vol. 2(Issue 45) pp:19427-19434
Publication Date(Web):17 Oct 2014
DOI:10.1039/C4TA04137B
Triboelectric generators have attracted considerable attention due to their rapidly improved electromechanical conversion efficiency. It is a great challenge to design a triboelectric generator to enable practical and effective operations. In this paper, we present a flexible interdigital-electrodes-based triboelectric generator (FITG) for harvesting sliding and rotating mechanical energy. When a film of flexible interdigital electrodes is placed on a plane, it can be used for harvesting sliding energy. When the film of the flexible interdigital electrodes is rolled into a cylinder, it can be used for harvesting rotating energy. In sliding mode, the maximum open-circuit voltage, short-circuit current and peak power density reach up to 400 V, 120 μA (10 mA m−2) and 13 W m−2, respectively, under a sliding velocity of 3.95 m s−1, which can be used to light tens of light-emitting diodes (LEDs) and to charge a commercial capacitor to 7.2 V within 35 s. The FITG can harvest the mechanical energy of mouse operation and traditional printing. In rotating mode, the maximum output voltage of the generator reaches as high as 1020 V at a rotating speed of 240 rpm. The FITG with interdigital electrodes on a flexible substrate has the advantages of light weight, resistance to wear, multifunction and high output power.
Co-reporter:Hengyu Guo, Xianming He, Junwen Zhong, Qize Zhong, Qiang Leng, Chenguo Hu, Jie Chen, Li Tian, Yi Xi and Jun Zhou
Journal of Materials Chemistry A 2014 vol. 2(Issue 7) pp:2079-2087
Publication Date(Web):19 Nov 2013
DOI:10.1039/C3TA14421F
Harvesting airflow energy and light energy from the ambient environment to build a self-powered system is attractive and challenging work. In this article, an airflow-induced triboelectric nanogenerator (ATNG) has been fabricated that converts wind energy to alternating electricity. The mechanism of ATNG has also been illustrated. The performance of ATNGs with different sizes was studied, from which we discovered that the ATNG (size: 1 cm × 3 cm, electrode gap: 1.5 mm) could easily collect energy from a gentle wind (5.3 m s−1). Due to the relatively high alternating electricity frequency (179.5–1220.9 Hz), an approximately stable output power (of up to 1.5 mW) was obtained from the ATNG (size: 1 cm × 3 cm, electrode gap: 0.5 mm) with 8.35 μC of charge transferred per second. Meanwhile, the fabricated wind energy harvesting device was used to drive 46 commercial green light-emitting diodes (LEDs) connected in series and charge a 220 μF capacitor to 2.5 V over 50 s. When combined with a dye-sensitized solar cell (DSC), the device can individually and simultaneously harvest wind and light energy. This shows the potential applications of this ATNG in self-powered systems.
Co-reporter:Shuge Dai, Hengyu Guo, Mingjun Wang, Jianlin Liu, Guo Wang, Chenguo Hu and Yi Xi
Journal of Materials Chemistry A 2014 vol. 2(Issue 46) pp:19665-19669
Publication Date(Web):22 Oct 2014
DOI:10.1039/C4TA03442B
A highly flexible solid-state micro-supercapacitor based on a pen ink-carbon-fiber (Ink-CF) thread structure was fabricated with excellent electrochemical performance such as a high capacitance of 4.31 mF cm−2 and an energy density of 3.8 × 10−7 W h cm−2 at a power density of 5.6 × 10−6 W cm−2. This fabricated structure shows excellent characteristics such as lightweight, small volume, flexibility and portability. By integrating it with a triboelectric nanogenarator, the micro-supercapacitors could be charged and power 8 commercial LEDs, demonstrating its feasibility as an efficient storage component for self-powered micro/nanosystems.
Co-reporter:Qiang Leng, Lin Chen, Hengyu Guo, Jianlin Liu, Guanlin Liu, Chenguo Hu and Yi Xi
Journal of Materials Chemistry A 2014 vol. 2(Issue 30) pp:11940-11947
Publication Date(Web):03 Jun 2014
DOI:10.1039/C4TA01782J
Waste heat has been regarded as one of the most important renewable and green energy sources, and its widespread reclamation could help to reduce the negative impacts of global warming and the energy crisis. In this work, we designed a pyroelectric generator based on a polyvinylidene fluoride film for harvesting the heat energy from hot/cold water, which widely exists in industrial processes. To achieve practical application, the device simply contacts a hot flow and cold flow alternately. The output open-circuit voltage and short-circuit current reached a maximum of 192 V and 12 μA, respectively, under a temperature change of 80 °C. The output power density can reach 14 μW cm, which is a great improvement for thermoelectric devices. The prepared pyroelectric generator can drive 42 green light-emitting diodes or charge a commercial capacitor (100 μF) to 3.3 V in 90 s. This work provides a promising strategy for efficiently harvesting waste heat from water and presents significant progress in thermoelectric conversion technology.
Co-reporter:Cuiling Zhang, Hulin Zhang, Kaiyou Zhang, Xiaoyan Li, Qiang Leng, and Chenguo Hu
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 16) pp:14423
Publication Date(Web):August 14, 2014
DOI:10.1021/am503696b
Photocatalytic degradation of organic contaminants is an important application area in solar energy utilization. To improve material photocatalytic properties, understanding their photocatalytic mechanism is indispensable. Here, the photocatalytic performance of ZnWO4 nanocrystals was systematicly investigated by the photodegradation of tetraethylated rhodamine (RhB) under simulated sunlight irradiation, including the influence of morphology, AgO/ZnWO4 heterojunction and comparison with CoWO4 nanowires. The results show that the photocatalytic activity of ZnWO4 is higher than that of CoWO4, and the ZnWO4 nanorods exhibit better photocatalytic activity than that of ZnWO4 nanowires. In addition, the mechanism for the difference of the photocatalytic activity was also investigated by comparison of their photoluminescence and photocurrents. AgO nanoparticles were assembled uniformly on the surface of ZnWO4 nanowires to form a heterojunction that exhibited enhanced photocatalytic activity under irradiation at the initial stage. We found that a good photocatalyst should not only have an active structure for electrons directly to transfer from the valence band to the conduction band without the help of phonons but also a special electronic configuration for the high mobility, to ensure more excited electrons and holes in a catalytic reaction.Keywords: band structure; carrier transport; heterostructure; nanomaterials; photocatalytic activity
Co-reporter:Hengyu Guo, Jie Chen, Li Tian, Qiang Leng, Yi Xi, and Chenguo Hu
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 19) pp:17184
Publication Date(Web):September 5, 2014
DOI:10.1021/am504919w
Humidity sensors are commonly based on the resistance change of metal oxide semiconductors, which show high sensitivity in low humidity but low sensitivity in high humidity. In this work, we design a novel humidity sensor based on the airflow-induced triboelectric nanogenerator (ATNG) that can serve as a self-powered sensor to detect humidity (especially in high humidity) and airflow rate. The output current or voltage change is investigated under different humidity (20–100% relative humidity) at fixed airflow rate and different airflow rates (15–25 L/min) at a fixed humidity. The working principle of the ATNG-based sensor is illustrated. We find that both output current and voltage can serve as a variable for detecting humidity, while only the output current can serve as a variable for determining airflow rate. Our study demonstrates an innovative approach toward detection of humidity and airflow rate with advantages of self-power, multifunction, low cost, simple fabrication, and high sensitivity.Keywords: airflow rate sensor; electrostatic induction; humidity sensor; nanogenerator; self-power; triboelectric effect
Co-reporter:Ying Zhao, Hengyu Guo, Hao Hua, Yi Xi, Chenguo Hu
Electrochimica Acta 2014 Volume 115() pp:487-492
Publication Date(Web):1 January 2014
DOI:10.1016/j.electacta.2013.10.205
•ZnO pyramid arrays assembled by thin nanoswires are synthesized and its photovoltaic properties are investigated.•Performs of the CdS QDSSCs based on the ZnO nanorod arrays, nanotube arrays, forest, and pyramid arrays are compared.•Pyramid arrays can achieve high photoelectric performs due to its anti-reflection, high specific area and direct electron transmission channels.Effect of ZnO architectures on photoelectric conversion efficiency of CdS quantum dot-sensitized ZnO solar cells is investigated. Four kinds of architecture assembled by one dimensional ZnO nanostructures, including ZnO nanorod arrays, nanotube arrays, forest, and pyramid arrays formed by thin nanowires, are designed and fabricated as photoanodes. Light-to-electricity conversion efficiency of these cells is 1.60% for the pyramid arrays, 1.34% for the forest, 1.08% for the nanotube arrays and 0.50% for the nanorod arrays, respectively, indicating that the architecture strongly affects the photoelectric conversion efficiency. Absorption spectra, dark current curves and photoelectron decay are measured to analyze the causes of differences. We find that light absorption and photoelectron transmission from ZnO nanostructures to FTO substrate are important factors for the cells. As the ZnO pyramid arrays formed by thin nanowires have anti-reflection character, high specific area for deposition of CdS sensitizer and fast photoelectron transmission channels to FTO substrate, higher photoelectric conversion efficiency is achieved. This investigation is important to the improvement on conversion efficiency for quantum dot-sensitized solar cells.
Co-reporter:Qi Yang, Lin Chen, Chenguo Hu, Shuxia Wang, Jicheng Zhang, Weidong Wu
Journal of Alloys and Compounds 2014 Volume 612() pp:301-305
Publication Date(Web):5 November 2014
DOI:10.1016/j.jallcom.2014.05.193
•A single Bi2S3 nanowire photoelectric device is fabricated.•Focused ion beam is used to deposit Ga induced Pt on the contacts between the nanowire and Au electrode.•The photoelectric properties of the devices are studied.•Single Bi2S3 nanowire devices show better performances compared with Bi2S3 thin film device.Long and high quality Bi2S3 nanowires (NWs) were obtained by a modified composite molten salt method. A single nanowire photoelectric device was fabricated by bridging a single Bi2S3 NW across two Au electrodes, and focused ion beam (FIB) was used to deposit Pt on the two contacts between the nanowire and the Au electrode for forming Ohmic contacts. For comparison another single nanowire device was made without using FIB. Photoelectric properties of the two devices were systematically investigated under simulation sunlight illumination at room temperature in the open air. Both single nanowire devices exhibit high sensitive photoelectric responses that are fully reversible and periodic. The device with the deposition of Pt shows a better stability than that of the device without deposition of Pt. In addition, both single nanowire devices exhibit better performance compared with the thin film device made of Bi2S3 NWs. The results imply that single Bi2S3 NW device is a promising candidate for fabricating optical detectors or optical switches.Graphical abstract
Co-reporter:Hengyu Guo, Xianming He, Chenguo Hu, Yongshu Tian, Yi Xi, Jie Chen, Li Tian
Electrochimica Acta 2014 120() pp: 23-29
Publication Date(Web):
DOI:10.1016/j.electacta.2013.12.099
Co-reporter:Xiaoyu He, Chenguo Hu, Yi Xi, Kaiyou Zhang, Hao Hua
Materials Research Bulletin 2014 50() pp: 91-94
Publication Date(Web):
DOI:10.1016/j.materresbull.2013.10.018
Co-reporter:Donglin Guo, Chenguo Hu, Qi Yang, Hao Hua, Wanjun Li, Chunyang Kong
Materials Research Bulletin 2014 53() pp: 102-106
Publication Date(Web):
DOI:10.1016/j.materresbull.2014.02.005
Co-reporter:Donglin Guo ; Hao Hua ; Qi Yang ; Xiaoyan Li
The Journal of Physical Chemistry C 2014 Volume 118(Issue 21) pp:11426-11431
Publication Date(Web):April 30, 2014
DOI:10.1021/jp5001489
We report the ferromagnetism of hexagonal CdS nanorods with a Curie temperature of 305 K, which is found in our experiments. Our first-principles calculations suggest that the magnetism is a result of the Cd vacancy. Compared with non-spin-polarized state in bulk CdS with one Cd vacancy, it is found that the ground state is spin-polarized. The Cd vacancy causes the electron configuration of S 2p to change from (a11↑)(a11↓)(t23↑)(t23↓) to (a11↑)(a11↓)(t23↑)(t21↓), forming a local magnetic moment of 1.67 μB, in agreement with the experimental results. The double exchange interactions of two S atoms should result in the observed magnetism.
Co-reporter:Donglin Guo ; Qi Yang ; Hao Hua
The Journal of Physical Chemistry C 2014 Volume 118(Issue 25) pp:13826-13832
Publication Date(Web):June 5, 2014
DOI:10.1021/jp504429g
Diluted magnetic semiconductors (DMSs), with Curie temperature at room temperature, are of technological and fundamental importance. Defect engineering has been an effective way to introduce magnetic moment in various nonmagnetic systems. Here, we report for the first time that BaMoO4 with oxygen vacancy shows ferromagnetic behavior. The first-principles calculations suggest that the oxygen vacancy is responsible for the ferromagnetism. When one oxygen vacancy is introduced, the related occupation state of Mo 4d is t2g1↑eg0, and a local magnetic moment of 1.0 μB is found. When two oxygen vacancies are introducd, the related occupation state of Mo 4d is t2g2↑eg0, and a local magnetic moment is up to 2.0 μB. Therefore, the magnetism results from the unpaired electrons on the d orbital, which show high-spin states. Our findings demonstrate that room-temperature ferromagnetism can also be induced through defect engineering.
Co-reporter:Xiaoyan Li, Chenguo Hu, Xueliang Kang, Qiang Len, Yi Xi, Kaiyou Zhang and Hong Liu
Journal of Materials Chemistry A 2013 vol. 1(Issue 44) pp:13721-13726
Publication Date(Web):19 Sep 2013
DOI:10.1039/C3TA12706K
Advanced thermoelectric technology offers the potential to convert waste heat into useful electricity, and a mechanism of transmission-free methods for solid state cooling. A low thermal conductivity is a prerequisite for obtaining high efficiency thermoelectric materials. It is a challenge to achieve low thermal conductivity without simultaneously destroying the electric conductivity, for which a ‘phonon glass/liquid–electron crystal’ is proposed. To realize the phonon glass–electron crystal, a host–guest cage crystal system is considered, while to realize the phonon liquid–electron crystal, superionic conductivity is needed. Here we report a novel material, a KCu7−xS4 nanowire, which exhibits enhanced thermoelectric properties compared to the traditional chalcogenide Cu7S4 nanostructure. The presence of K ions not only forms a clathrate and a superionic fluid structure, which provides the phonon glass and liquid–electron crystal, but also adjusts the product to give a nanowire-like morphology. A low thermal conductivity and large Seebeck coefficient can be achieved when the nanowires are pressed into a bulk material. Higher electrical conductivity is also obtained below 420 K. In addition, the numerous grain boundaries, Cu deficiency and the orientated nanowires further increase the thermoelectric properties. The results indicate a new strategy to obtain high efficiency thermoelectric materials by introducing kalium into copper chalcogenides to form a new crystal structure with ‘phonon glass and liquid–electron crystal’ properties.
Co-reporter:Hao Hua, Chenguo Hu, Zhenhuan Zhao, Hong Liu, Xiao Xie, Yi Xi
Electrochimica Acta 2013 Volume 105() pp:130-136
Publication Date(Web):30 August 2013
DOI:10.1016/j.electacta.2013.05.002
•Submicrometer-sized TiO2 spheres are employed to obtain highly efficient Pt/TiO2 electrocatalyst.•This electrocatalyst used for alcohol oxidation exhibits quite outstanding property.•The enhanced catalytic activity of the Pt/TiO2 spheres is owing to the mesoporous active sites and synergistic effect of Pt and TiO2.High electrocatalytic activity for alcohol electrooxidation by Pt nanoparticles supported on submicrometer-sized TiO2 spheres is achieved. The Pt nanoparticles with a diameter of 8–20 nm are uniformly coated on the surface of the submicrometer-sized TiO2 spheres with a diameter of 370–500 nm via a simple wet chemical synthesis. The electrocatalytic performances of the Pt/TiO2 submicrometer-sized TiO2 spheres for methanol and ethanol in acidic and alkaline media are investigated systematically by electrochemical methods. Compared with the Pt catalyst supported on the commercial carbon black, the Pt/TiO2 spheres exhibit an excellent enhanced electrocatalytic activity and stability owing to the mesoporous active sites, synergistic effect of Pt/TiO2, and micro-channels for liquid diffusion and gaseous product to escape.
Co-reporter:Donglin Guo, Chenguo Hu, Yi Xi
Applied Surface Science 2013 Volume 268() pp:458-463
Publication Date(Web):1 March 2013
DOI:10.1016/j.apsusc.2012.12.127
Abstract
Monoclinic LaPO4 and Fe doped LaPO4 have been prepared by the hydrothermal method in an acid aqueous solution. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction spectrum and X-ray photoelectron spectra are used to characterize the structure, morphology and composition of the samples. The pure LaPO4 sample shows paramagnetism at room temperature, but the Fe doped LaPO4 sample shows ferromagnetism with the coercivity of 166 Oe and saturated magnetization of 3.28 × 10−2 emu/g, respectively. The magnetic mechanism of the Fe doped LaPO4 sample has been discussed according to the electron density of states calculation by using the Vienna ab initio simulation package. The results indicate that the origin of ferromagnetism is mediated by the double exchange mechanism, in which impurity bands are formed and partially occupied in the band gap of the LaPO4, and the exchange split is larger than the bandwidth of t2g.
Co-reporter:Hulin Zhang, Dongzhou Wang, Chenguo Hu, Xueliang Kang, Hong Liu
Sensors and Actuators B: Chemical 2013 Volume 184() pp:288-294
Publication Date(Web):31 July 2013
DOI:10.1016/j.snb.2013.04.085
Sn1−xCoxO2 (x = 0, 0.01, 0.03, 0.05, 0.07) nanostructures with different morphologies are prepared by a facile hydrothermal method. The analysis from X-ray photoelectron spectroscopy indicates that the cobalt doped in SnO2 exists as Co2+. The room-temperature ferromagnetism is observed in the powder sample of Sn1−xCoxO2 with x = 0.01. The magnetic hysteresis loop is observed at room temperature with coercivity (Hc) of 120 Oe and remanent magnetization (Mr) of 3.04 × 10−2 emu/g. UV–vis spectra reveal the red shift of the band edge absorption of SnO2 after being doped with Co. The application of Sn1−xCoxO2 nanostructures in the gas sensor for detecting ethanol and acetone reveals that the as-prepared Sn1−xCoxO2 nanourchins with x = 0.03 show a high sensitivity and short response/recovery time.
Co-reporter:Donglin Guo, Hao Hua, Chenguo Hu, and Yi Xi
The Journal of Physical Chemistry C 2013 Volume 117(Issue 27) pp:14281-14288
Publication Date(Web):June 14, 2013
DOI:10.1021/jp402491w
Optical and magnetic properties of the perovskite barium niobate (BaNbO3) nanocubes are investigated before and after UV irradiation. The energy gap changes from 3.94 to 3.88 eV, and light absorption ability increases after UV irradiation. The X-ray photoelectron spectroscopy (XPS) spectra reveal that the BaNbO3 nanocubes contain oxygen vacancy. The BaNbO3 nanocubes show weak ferromagnetism, but the saturation magnetization is enhanced from 4.34 × 10–3 to 6.60 × 10–3 emu/g after UV irradiation. The calculations indicate that the ferromagnetism is due to two +2 charge oxygen vacancies (VO12+ – VO52+) which cause unpaired electrons around the oxygen vacancy occupying the d state of the nearest-neighbor Nb atom. The total magnetic moment increases from 0.942 to 1.76 μB owing to an increase of the concentration of the oxygen vacancy in BaNbO3. The theoretical consequence well matches the laboratorial result.
Co-reporter:Qi Yang, Chenguo Hu, Shuxia Wang, Yi Xi, and Kaiyou Zhang
The Journal of Physical Chemistry C 2013 Volume 117(Issue 11) pp:5515-5520
Publication Date(Web):February 28, 2013
DOI:10.1021/jp307742s
Bismuth sulfide (Bi2S3) is a specific thermoelectric material that thermoelectric properties are anisotropic. One dimensional Bi2S3 structure would improve the conductivity and Seebeck coefficient because of the anisotropic electron transmission and phonon scattering. The Bi2S3 nanostructures with different morphologies are prepared by a modified composite molten salt method. The Bi2S3 nanowires with lengths up to 20 μm and high crystallization are obtained. The thermoelectric properties of the synthesized samples with different morphologies are comparatively investigated. We find that the power factor of the film made from the Bi2S3 nanowires is much larger than that of the film made by the Bi2S3 nanosheets or nanowires mixed with sheets due to its lower resistivity and larger Seebeck coefficient. The low resistivity of the Bi2S3 nanowires film is a result of the high carrier concentration and high carrier mobility due to the high orientation degree and better crystallization. The Bi2S3 nanowires orientated along the film plane gives fast electron transmission along the a–c or b–c planes (electron crystal), and efficient phonon scattering between the cleaved a–c planes or b–c planes and between grains of the nanowires (phonon glass). The introduction of many interfaces from smaller size of grains, which scatter phonons more effectively than electrons, or serve to filter out the low-energy electrons at the interfacial energy barriers, allows the enhancement of Seebeck coefficient.
Co-reporter:Donglin Guo ; Chenguo Hu ; Yi Xi ;Kaiyou Zhang
The Journal of Physical Chemistry C 2013 Volume 117(Issue 41) pp:21597-21602
Publication Date(Web):September 25, 2013
DOI:10.1021/jp4080465
Electronic and transport properties of Bi2O2Se under strain are calculated using Tran–Blaha modified Becke–Johnson (TB-mBJGGA) potential and semiclassical Boltzmann transport theories. The electronic band gap decreases with tensile and compressive in-plane strain. We predict that the n-type Seebeck coefficient can be increased under compressive in-plane strain, while the p-type Seebeck coefficient can be increased under tensile in-plane strain. Further, the power factor of n-type doping Bi2O2Se can be increased under compressive in-plane strain, while that of p-type doping Bi2O2Se can be increased under tensile in-plane strain. For p-type doping Bi2O2Se, large thermoelectric figure of merit (ZT ≈ 1.42) could be obtained under tensile strain (2.3%) at 800 K. Moreover, a higher ZT ≈ 1.76 could be achieved along the ZZ direction. This study demonstrates that the electronic and thermoelectric properties can be controlled by strain engineering in thermoelectric material.
Co-reporter:Donglin Guo, Chenguo Hu, Cuiling Zhang
Materials Research Bulletin 2013 48(5) pp: 1984-1988
Publication Date(Web):
DOI:10.1016/j.materresbull.2013.02.004
Co-reporter:Kaiyou Zhang, Chenguo Hu, Xueliang Kang, Shuxia Wang, Yi Xi, Hong Liu
Materials Research Bulletin 2013 48(10) pp: 3968-3972
Publication Date(Web):
DOI:10.1016/j.materresbull.2013.06.013
Co-reporter:Xiaoyan Li, Chenguo Hu, Zhenhuan Zhao, Kaiyou Zhang, Hong Liu
Sensors and Actuators B: Chemical 2013 Volume 182() pp:461-466
Publication Date(Web):June 2013
DOI:10.1016/j.snb.2013.03.029
Cubic CdS nanoparticles and hexagonal CdS nanowalls were fabricated directly on Cd foils via a modified composite hydroxide mediated approach. The phase transition of CdS nanocrystals from cubic to hexagonal phase can be controlled by varying the water content in the hydroxide melts. The metal Cd foils serves as both Cd source and substrate in the formation of the CdS nanostructures. The surface morphology and phase structure were characterized by scanning electron microscope, energy dispersive X-ray spectrometer and X-ray diffraction. The obviously enhanced photoelectrochemical performances of the hexagonal nanowalls were found under the illumination of the simulated sunlight in comparison with that of the cubic CdS nanoparticles. The surface morphology plays a vital role in its photoelectrochemical behaviors due to the different specific surface area and charge transport, indicating such three-dimensional hexagonal CdS nanostructure has prominent advantages in photoelectrochemical applications.
Co-reporter:Xiaoyan Li, Chenguo Hu, Xue Wang, Yi Xi
Applied Surface Science 2012 Volume 258(Issue 10) pp:4370-4376
Publication Date(Web):1 March 2012
DOI:10.1016/j.apsusc.2011.12.116
Abstract
Single-crystalline CdS nanoparticles were synthesized for the first time by the composite-molten-salt (CMS) method, with advantages of one-step, ambient pressure, low temperature, template-free and low cost. The influence of temperature, growth time and amount of salts on the morphology of CdS nanoparticles was systematically investigated. It shows that a smaller size of CdS nanoparticles can be obtained under lower temperature, less growth time and more composite salts. UV–vis reflection spectrum of the nanoparticles reveals that the nanoparticles have a bandgap of 2.34 eV. Photoluminescence spectrum was also carried out to explore its optical property. Photocatalytic degradation of rhodamine B (RhB) and methylene blue (MB) in presence of the CdS nanoparticles was compared with that in presence of the commercial TiO2 nanoparticles under the simulated sunlight.
Co-reporter:Donglin Guo, Chenguo Hu
Applied Surface Science 2012 Volume 258(Issue 18) pp:6987-6992
Publication Date(Web):1 July 2012
DOI:10.1016/j.apsusc.2012.03.149
Abstract
The electronic structure and optical properties of SnO2 with consideration of oxygen vacancy are computed using the first-principles plane-wave pseudopotential method based on the density functional theory. The results show that SnO2 with oxygen vacancy has a band gap of 1.03 eV, and the Fermi level shift upward to the conduction band, showing a typical n-type character; besides oxygen vacancy would introduce a new electronic state within the band gap compared with that of pure SnO2. Moreover, certain impurity levels are located near the top of the valence band, which narrows the band gap of the compound. Optical properties, including the dielectric function, reflectivity, absorption coefficient and the energy-loss spectrum are calculated and the results are in good agreement with the experiments. The calculated absorption coefficient shows that SnO2 with oxygen vacancy exhibits an absorption band in the visible region, centered at 2.10 eV (588 nm). It is demonstrated that oxygen vacancy causes the visible light absorption band.
Co-reporter:Chunlan Cao, Chenguo Hu, Weidong Shen, Shuxia Wang, Yongshu Tian, Xue Wang
Journal of Alloys and Compounds 2012 Volume 523() pp:139-145
Publication Date(Web):15 May 2012
DOI:10.1016/j.jallcom.2012.01.126
TiO2/CdS core–shell nanorod arrays have been fabricated via a two-step method. Vertically aligned TiO2 nanorod arrays (NRs) were synthesized by a facile hydrothermal method, and followed by depositing CdS nanoparticles on TiO2 NRs by spin-coating successive ion layer adsorption and reaction (spin-SILAR) method. The surface morphology, structure, optical and photoelectrochemical behaviors of the core–shell NRs films are considered. The UV–vis absorption spectrum results suggested that the absorption peak of the TiO2/CdS core–shell NRs shifts from the ultraviolet region to the visible region in comparison to that of the pure TiO2 NRs. The obviously enhanced photoelectrochemical (PEC) performances of the heterojunction NRs were found under illumination of the simulated sunlight in comparison with that of the TiO2 NRs. The enhanced PEC performance and formation mechanism of TiO2/CdS core–shell NRs were discussed in detail.Highlights► TiO2/CdS core–shell nanorod arrays were fabricated by spin-SILAR method. ► The enhanced photocurrent was found in the TiO2/CdS core–shell nanorod arrays. ► The CdS coated on TiO2 increases the e-h separation and enlarges light absorption range.
Co-reporter:Jing Xu, Chenguo Hu, Yi Xi, Buyong Wan, Cuiling Zhang, Yan Zhang
Solid State Sciences 2012 Volume 14(Issue 4) pp:535-539
Publication Date(Web):April 2012
DOI:10.1016/j.solidstatesciences.2012.01.013
β-AgVO3 nanowires are synthesized by the hydrothermal method. The synthesis yields nanowires with a monoclinic phase structure. Typical nanowires have diameter of about 200–700 nm and length up to 300 μm. Photocatalytic degradation of Rhodamine B dye is investigated. It is found that the β-AgVO3 nanowires possess excellent catalytic degradation activity owing to its effective visible light absorption and well crystallization. The highly photocatalytic activity suggest its possible application in the organic pollutant treatment under visible light irradiation.β-AgVO3 nanowires with length larger than 300 μm are synthesized and can be used as a new photocatalyst to efficiently degrade RHB under visible light irradiation.
Co-reporter:Xiao Xie ; Chenguo Hu ; Donglin Guo ; Hao Hua ; Tengjiao Liu ;Peng Jiang
The Journal of Physical Chemistry C 2012 Volume 116(Issue 43) pp:23041-23046
Publication Date(Web):October 11, 2012
DOI:10.1021/jp306370q
Perovskite-type structure BaNbO3 and Fe/Co-doped BaNbO3 nanocubes with a pure cubic phase have been synthesized by a composite-hydroxide-mediated method. X-ray diffraction and X-ray photoelectron spectroscopy reveal that Fe3+/Co2+ are incorporated into the BaNbO3 lattices. These doped samples exhibit smaller band gaps and semiconducting conduction quite different from the characteristics of BaNbO3. The resistivity is reduced 3–4 orders of magnitude after doping the BaNbO3 with Fe and Co ions. By comparing with the pure BaNbO3, we found that ferromagnetic property is achieved on the Fe/Co-doped BaNbO3 samples. The mechanism of magnetic property for Fe/Co-doped BaNbO3 is discussed by density functional theory, which provides an evident 3d transition metal doped easily in substitution of the B site element to produce ferromagnetism in ABO3-type ferroelectric semiconductor oxide. The report indicates that the 3d transition metal doped BaNbO3 may be a good candidate for new multiferroics.
Co-reporter:Xiaoyu He;Qianning Yi;Xue Wang;Hao Hua;Xiaoyan Li
Catalysis Letters 2012 Volume 142( Issue 5) pp:637-645
Publication Date(Web):2012 May
DOI:10.1007/s10562-012-0785-5
Multi-structural tungsten oxide (WO3·0.33H2O) samples were prepared using a hydrothermal method in the presence of different salts Na2SO4 and CaCl2 respectively. The experimental results showed that pH value of the reaction solution greatly affects crystal morphology of the final products. To explore the photocatalysis originated from nanonetwork hierarchical structure, the photodegradation of methylene blue was carried out under simulated sunlight irradiation. The photocatalytic activity of the WO3·0.33H2O nanonetworks was compared with that of the nanoplates, and the former showed a higher photocatalytic activity owing to its novel hierarchical structure. Our investigation demonstrates that nanonetwork hierarchical structure can promote sunlight absorption due to higher specific surface area.
Co-reporter:Muhammad Hashim, Chenguo Hu, Cuiling Zhang, Xiao Xie
Physica E: Low-dimensional Systems and Nanostructures 2012 Volume 46() pp:213-217
Publication Date(Web):September 2012
DOI:10.1016/j.physe.2012.09.023
Magnetic property of anorthic phase Ag2Mo2O7 nanowires with width of 2 μm and length up to 40 μm synthesized by hydrothermal method was studied for the first time. The Ag2Mo2O7 nanowires exhibit ferromagnetic property at room temperature with coercivity 127.7 Oe and remanent magnetization 16.9×10−3 emu/g. The magnetic mechanism has been discussed according to the calculated results of the spin-polarized density functional theory (DFT), which was carried out by the Vienna ab initio Simulation Package (VASP) using projector augmented wave (PAW) pseudopotential to describe the interaction between electron and ion for Ag2Mo2O7 crystal, demonstrating that the magnetism is caused by oxygen vacancies. The photoluminescence spectrum measured at room temperature also indicates the oxygen vacancies in the Ag2Mo2O7 nanowires.Graphical abstractRoom temperature magnetic property of the anorthic phase Ag2Mo2O7 nanowires was found, which mainly comes from the deformation of the crystal lattices and electrons trapped by the oxygen vacancies in Ag2Mo2O7 crystal.Highlights► Room temperature ferromagnetic property of the Ag2Mo2O7 nanowires was studied first time. ► The value of coercivity was 127.7 Oe and remanent magnetization was 16.9×10−3 emu/g. ► Magnetic property is caused from deformation of lattices and electrons trapped by oxygen vacancies. ► The photoluminescence spectrum measured at room temperature confirmed the oxygen vacancies.
Co-reporter:Yongshu Tian, Chenguo Hu, Xiaohui Wu, Qing Wu, Chunlan Cao
Solar Energy Materials and Solar Cells 2012 98() pp: 83-87
Publication Date(Web):
DOI:10.1016/j.solmat.2011.10.023
Co-reporter:Hulin Zhang;Siguo Chen;Kaiyou Zhang;Xue Wang
Catalysis Letters 2012 Volume 142( Issue 6) pp:809-815
Publication Date(Web):2012 June
DOI:10.1007/s10562-012-0826-0
SnO2 hierarchical architectures were synthesized with a surfactant-free hydrothermal synthesis route. We found that the acid or alkaline amount (HCl or NaOH) of the solution had a remarkable effect on the morphology of as-synthesized products. The SnO2 nanostructures were selected as a support of Pt catalyst (Pt/SnO2) for hydrogen evolution reaction (HER) in the acidic media. The influence of SnO2 morphologies on the electrochemical performance has been investigated by cyclic voltammetry and linear sweeping voltammetry using the rotating disk electrodes. In addition, the effect on the catalytic activity in different electrolyte concentration was taken into account. Kinetic study shows that the HER on the Pt/SnO2(flower) electrocatalyst gives a higher exchange current density and a lower overpotential in H2SO4 solution with high concentration.
Co-reporter:Muhammad Hashim, Chenguo Hu, Xue Wang, Buyong Wan, Jing Xu
Materials Research Bulletin 2012 47(11) pp: 3383-3389
Publication Date(Web):
DOI:10.1016/j.materresbull.2012.07.019
Co-reporter:Hulin Zhang, Chenguo Hu, Xiaoshan He, Liu Hong, Guojun Du, Yan Zhang
Journal of Power Sources 2011 Volume 196(Issue 10) pp:4499-4505
Publication Date(Web):15 May 2011
DOI:10.1016/j.jpowsour.2011.01.030
SnO2 nanoflowers and nanorods have been synthesized by the hydrothermal method without using any capping agent. Both types of SnO2 nanostructures are selected as a support of Pt catalyst for methanol and ethanol electrooxidation. The synthesized SnO2 nanostructures and SnO2 supported platinum (Pt/SnO2) catalysts are characterized by X-ray diffraction, scanning electron microscope and high resolution transmission electron microscope. The electrocatalytic properties of the Pt/SnO2 and Pt/C catalysts for methanol and ethanol oxidation have been investigated systematically by typical electrochemical methods. The influence of SnO2 morphology on its electrocatalytic activity is comparatively investigated. The Pt/SnO2 flower-shaped catalyst shows higher electrocatalytic activity and better long-term cycle stability compared with other electrocatalysts owing to the multidimensional active sites and radial channels of liquid diffusion.Graphical abstractThe multidimensional Pt/SnO2 catalysts have been successfully obtained by uniform distribution of Pt nanoparticles on the SnO2 flowers, which exhibit a highly catalytic oxidation activity to methanol and ethanol in acid solution.Research highlights▶ The SnO2 nanoflowers are employed to obtain multidimensional Pt/SnO2 catalysts. ▶ The catalyst of multidimensional active sites and radial channels is used for alcohol oxidation. ▶ The catalyst shows higher electrocatalytic activity and better long-term cycle stability.
Co-reporter:Xue Wang, Chenguo Hu, Yufeng Xiong, Hong Liu, Guojun Du, Xiaoshan He
Journal of Power Sources 2011 Volume 196(Issue 4) pp:1904-1908
Publication Date(Web):15 February 2011
DOI:10.1016/j.jpowsour.2010.09.072
Carbon nanospheres with diameters ∼200 nm have been synthesized from glucose at 200 °C and normal atmosphere by a novel composite-molten-salt (CMS) method. Pt nanoparticles supported on those carbon nanospheres are used for methanol and ethanol electro-oxidation in alkaline media. Experimental results demonstrate that, in comparison with the carbon black or hydrothermally-synthesized carbon nanosphere support, CMS carbon-nanosphere-supported Pt electrocatalyst shows an enhanced efficiency for both methanol and ethanol electro-oxidation in terms of electrode conductivity, electrochemically active surface, oxidation peak current density and onset potential. This enhancement is considered to be not only due to the high carbonization of the CMS synthesized carbon nanospheres, but also due to the formation of a porous structure by the carbon nanospheres which significantly reduces the liquid sealing effect allowing efficient gas diffusion.The Pt catalyst supported on the newly synthesized carbon nanospheres exhibits a much higher catalytic activity for methanol and ethanol electrooxidationin alkaline media than that of the Pt catalyst supported on the commercially available carbon black or on the hydrothermal synthetic carbon nanospheres.
Co-reporter:Qianning Yi, Chenguo Hu, Rusen Yang, Hong Liu, Buyong Wan, Yan Zhang
Journal of Alloys and Compounds 2011 Volume 509(Issue 26) pp:L255-L261
Publication Date(Web):30 June 2011
DOI:10.1016/j.jallcom.2011.04.066
Three-dimensional WO3 network squares have been fabricated on a large scale by a hydrothermal method at 160 °C without any template or surfactant. The characterization of the network squares with X-ray diffraction, scanning electron microscopy, and transmission electron microscopy indicates a single crystalline hexagonal structure with a square of side length up to 20 μm. The influence of pH value on the morphology of the final product has been studied, indicating that more uniform WO3 network squares can be obtained at pH 1.7. A possible growth mechanism involves the Ostwald ripening, oriented attachment and etching effect. The UV–vis reflection spectrum indicates a band gap of ∼3.2 eV. The photodetector based on a single WO3 network square shows remarkable photosensitivity under intermittent illumination of the simulated sunlight, which could mainly be attributed to the specific network structure of WO3 and the Schottky contacts.Graphical abstractHighlights► Three-dimensional WO3 network squares have been firstly fabricated on a large scale. ► The photodetector based on a single WO3 network square shows remarkable photosensitivity owing to the specific network structure and the introducing of Schottky contacts. ► The influence of pH value on the morphology of the final product has been studied.
Co-reporter:Jing Xu, Chenguo Hu, Gaobin Liu, Hong Liu, Guojun Du, Yan Zhang
Journal of Alloys and Compounds 2011 Volume 509(Issue 30) pp:7968-7972
Publication Date(Web):28 July 2011
DOI:10.1016/j.jallcom.2011.05.051
NdVO4 nanowires are synthesized by a simple composite molten salt method. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction spectrum, energy dispersive spectrometry and UV–vis spectrum are used to characterize the structure, morphology and composition of the sample. The results show that the product is of tetragonal phase NdVO4 nanowires which are connected together in bases, rooted in one center, with typical diameters of 100 nm and lengths up to 3 μm. The UV–vis spectrum shows that NdVO4 nanowires have four strong absorption peaks from the UV to near infrared region. The photocatalytic degradation of Rhodamine B (RhB) and methyl orange under visible light irradiation using the NdVO4 nanowires are also investigated. Excellent catalytic degradation activity of RhB observed suggests possible applications for organic pollutant treatment under visible light irradiation. The electron density states of the NdVO4 were calculated with the Vienna ab initio simulation package. The results of these simulations were used to form a description of the observed light absorption and photodegradation properties of NdVO4 nanowires.Graphical abstractNdVO4 nanowires are synthesized by a simple composite molten salt method. The effective light absorption and photodegradation are found.Highlights► We report the fabrication, characterization and photocatalytic activity of NdVO4 nanowires synthesized by the composite molten salt method. ► The NdVO4 nanowires show effective light absorption and high catalytic degradation activity to Rhodamine B. ► The electron density states of the NdVO4 were calculated with the Vienna ab initio simulation package, which explains the light absorption and photodegradation properties.
Co-reporter:Yan Zhang, Chenguo Hu, Bin Feng, Xue Wang, Buyong Wan
Applied Surface Science 2011 Volume 257(Issue 24) pp:10679-10685
Publication Date(Web):1 October 2011
DOI:10.1016/j.apsusc.2011.07.078
Abstract
Spherical flowerlike hierarchical structure of ZnSe(en)0.5 was synthesized via a solvothermal route in the NH3·H2O–ethylenediamine (en)–N2H4·H2O system at 180 °C for 24 h. The hierarchical structure is assembled from lots of regular nanosheets. The ZnSe(en)0.5 was further converted into pure hexagonal ZnSe by annealing in a flowing nitrogen gas at 500 °C for 1 h with morphology preserved. The formation mechanism of ZnSe was discussed. The UV–visible absorption spectrum and PL spectrum of the ZnSe spherical flowerlike hierarchical structure were measured. In addition, photocatalytic activity of the ZnSe flowerlike structure for the degradation of methyl orange under the irradiation of the simulated sunlight was investigated. The excellent catalytic activity for the degradation of methyl orange was found and the possible mechanism of the photocatalytic activity is also proposed.
Co-reporter:Yongshu Tian, Chenguo Hu, Qing Wu, Xiaohui Wu, Xiaoyan Li, Muhammad Hashim
Applied Surface Science 2011 Volume 258(Issue 1) pp:321-326
Publication Date(Web):15 October 2011
DOI:10.1016/j.apsusc.2011.08.058
Abstract
The fill factor of dye-sensitized solar cells based on the ZnO nanowire array is very low, which is usually ascribed to a rapid charge recombination. In this article, the influence on the fill factor of ZnO nanowire array cell is investigated and discussed by comparing dark current and decay rate of open circuit potential of the ZnO nanowire array cell with those of the ZnO nanoparticle cell, TiO2 nanoparticle cell and TiO2-coated ZnO nanowire array cell. The results demonstrate that the low fill factor of the ZnO nanowire array cell is largely caused by a rapid decrease of electron injection efficiency rather than a rapid charge recombination, which is decided by the absorption nature of Ru-complexed dye molecules on ZnO surface and repellency of radial electric field. The fill factor of the ZnO nanowire array cell can be improved by coating ZnO nanowires with a wide band gap semiconductor material or metal oxide insulator.
Co-reporter:Chuanhui Xia, Chenguo Hu, Yongshu Tian, Peng Chen, Buyong Wan, Jing Xu
Solid State Sciences 2011 Volume 13(Issue 2) pp:388-393
Publication Date(Web):February 2011
DOI:10.1016/j.solidstatesciences.2010.11.041
Fe-doped ZnO rod arrays have grown on zinc foils by the hydrothermal method at temperature of 180 °C. The doping Fe content can be controlled by varying the reaction time. X-ray diffraction and X-ray photoelectron spectroscopy results provide the evidence that Fe3+ is incorporated into the ZnO lattices. Photoluminescence spectrum of the rod arrays shows that the emission peak shifts a little to lower energy and its intensity decreases with the increase of Fe content. The green emission resulting from oxygen vacancy is observed when excessive Fe ions are doped in ZnO. The rod arrays have exhibited room-temperature ferromagnetic behavior with the remanence of 0.293, 0.613 and 0.557 emu/cm3 for the Fe concentration of 0.50, 1.22 and 2.00 at%, respectively. The exchange interaction between local spin-polarized electrons and conductive electrons is proposed as a cause of the room-temperature ferromagnetism.
Co-reporter:Zhiyi Zhang, Chenguo Hu, Muhammad Hashim, Peng Chen, Yuanqiang Xiong, Cuiling Zhang
Materials Science and Engineering: B 2011 Volume 176(Issue 9) pp:756-761
Publication Date(Web):25 May 2011
DOI:10.1016/j.mseb.2011.02.018
Monoclinic FeMoO4 nanorods have been prepared by the hydrothermal method in an acid aqueous solution. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction spectrum, X-ray photoelectron spectra and differential scanning calorimetry are used to characterize the structure, morphology and composition of the sample. The FeMoO4 nanorods exhibit a ferromagnetic property at room temperature with the coercivity of 31.1 Oe and remnant magnetization of 4.09 × 10−3 emu/g, respectively. The magnetic mechanism has been discussed according to the calculated results of electron density of states for FeMoO4 with consideration of oxygen vacancies by using the Vienna ab initio simulation package.
Co-reporter:Chunlan Cao, Chenguo Hu, Xue Wang, Shuxia Wang, Yongshu Tian, Hulin Zhang
Sensors and Actuators B: Chemical 2011 Volume 156(Issue 1) pp:114-119
Publication Date(Web):10 August 2011
DOI:10.1016/j.snb.2011.03.080
Highly oriented TiO2 nanorod arrays were fabricated directly on fluorine-doped tin oxide-coated glass (FTO) substrate by the hydrothermal method. The diameter, length, and density of the nanorods could be varied by changing the growth parameters, such as time, temperature, and initial reactant concentration. The fabricated samples were characterized with X-ray diffraction, field-emission-scanning electron microscopy, transmission electron microscopy, high resolution transmission electron microscopy and energy dispersive X-ray spectroscopy. The TiO2 nanorod array was applied to construct photoelectric devices, by which highly sensitive and steady photocurrent responses were obtained.
Co-reporter:Jing Xu, Chenguo Hu, Yi Xi, Chen Peng, Buyong Wan, Xiaoshan He
Materials Research Bulletin 2011 46(6) pp: 946-950
Publication Date(Web):
DOI:10.1016/j.materresbull.2011.02.023
Co-reporter:Jing Xu, Chenguo Hu, Yi Xi, Yanxue Chen, Hong Liu, Buyong Wan
Physica E: Low-dimensional Systems and Nanostructures 2011 Volume 43(Issue 4) pp:938-942
Publication Date(Web):February 2011
DOI:10.1016/j.physe.2010.11.021
Lead vanadium oxide hydroxide nano- and micro-crystals have been synthesized by a simple Composite-Hydroxide-Mediated (CHM) method. The synthesized products were characterized by XRD, SEM, TEM, and UV–vis spectrum. The morphology of the product could be tuned from separate rods to rod bunches by simply controlling the reaction parameters. The UV–visible spectrum shows that the band gap of the Pb5(VO4)3OH is 2.92 eV. The photoluminescence have been investigated in the temperature range 10–300 K. The results indicate a blue luminescence at room temperature and a strong red luminescence at low temperatures under excitation of 325 nm laser. The luminescent mechanism of the Pb5(VO4)3OH was discussed.Research highlights► It is for the first time that Pb5(VO4)3OH nano-rod bunches are synthesized by the composite-hydroxide-mediated method. The method is simple, easy to scale-up, and without using organic dispersant or surface capping agent. ► The shape and size of Pb5(VO4)3OH can be easily tuned by adjusting the growth time and ratio of Pb:V in raw materials. ► The optical properties have been investigated in 10–300 K. The results indicate a blue luminescence in room temperature and a strong red luminescence in low temperature under excitation at 325 nm.
Co-reporter:Kaiyou Zhang, Chenguo Hu, Yongshu Tian, Chunhua Zheng, Buyong Wan
Physica E: Low-dimensional Systems and Nanostructures 2011 Volume 43(Issue 4) pp:943-947
Publication Date(Web):February 2011
DOI:10.1016/j.physe.2010.11.022
Photoelectric device has been fabricated using cadmium selenide nanorods with diameter of 200 nm and length of 1 μm, which are obtained by the modified composite-hydroxide-mediated approach. The photoelectric effect of the device has been systematically characterized under the irradiation of a simulated sunlight, including characteristics such as I–V curves, photostability, photocurrent versus illuminant intensity, photocurrent versus electric field intensity, photocurrent response speed, and reproducibility. The highly sensitive responses to light shifts and excellent stability of sustained photocurrent in exposure to light of the device demonstrate its great potential applications as optical sensors/switches with a response time in ∼ms range.Research Highlights► Our device has many advantages such as a fast response speed, good stability, easy preparation, and cost effectiveness in comparison with the device made from CdSe thin films obtained from high vacuum system synthesis.
Co-reporter:Chunhua Zheng, Chenguo Hu, Xueyan Chen, Hong liu, Yufeng Xiong, Jing Xu, Buyong Wan and Linyong Huang
CrystEngComm 2010 vol. 12(Issue 10) pp:3277-3282
Publication Date(Web):24 Jun 2010
DOI:10.1039/C004327C
Raspite PbWO4, which is rare in nature, poses a great challenge to laboratory preparation and only limited optical and spectroscopic investigations have been conducted on raspite PbWO4 crystals from nature. In this article, we report that raspite PbWO4 nanobelts can be obtained by a facile composite-salt-mediated synthesis method without using any surface-capping agent. The nanobelts are well crystallized with lengths up to hundreds of microns. The synthesis method is simple and cost effective. Our investigation demonstrates that the raspite PbWO4 nanobelts possess excellent blue–green luminescent property at low temperature and highly sensitive photocurrent response to light switches at room temperature. The growth mechanism of the raspite PbWO4 nanobelts, the structure characteristic and the luminescent mechanism are discussed in detail.
Co-reporter:Buyong Wan, Chenguo Hu, Yi Xi, Jing Xu, Xiaoshan He
Solid State Sciences 2010 Volume 12(Issue 1) pp:123-127
Publication Date(Web):January 2010
DOI:10.1016/j.solidstatesciences.2009.10.016
The pure face-centered cubic lead chalcogenide nanocubes have been synthesized in hydrazine hydrate saturated alkaline solution under the conditions of room temperature, ambient pressure, and a short growth time, with advantages of being simple, high yield and cost effective. The size of PbS, PbSe and PbTe nanocubes is 200–300 nm, 50–120 nm, and 30–60 nm, respectively. It was found that the growth steps of lead chalcogenides (especially PbTe) nanostructures could be controlled in the strong hydrazine hydrate alkaline environment. Thermoelectric properties of the films made from the PbS, PbSe and PbTe nanocubes have been investigated comparatively for the first time. The results indicate that the room-temperature Seebeck coefficient value of the PbS, PbSe and PbTe nanocube films is up to 154.4 μV/K, 199.8 μV/K and 451.1 μV/K, respectively.
Co-reporter:Buyong Wan, Chenguo Hu, Bin Feng, Jing Xu, Yan Zhang, Yongshu Tian
Materials Science and Engineering: B 2010 Volume 171(1–3) pp:11-15
Publication Date(Web):25 July 2010
DOI:10.1016/j.mseb.2010.03.046
ZnTe nanorods have been synthesized in hydrazine hydrate solution at a low temperature of 80 °C and subsequent thermal treatment in N2. The advantages of this method are of simplicity, easy to scale-up, low cost, and without using any organic dispersant or surface capping agent. Scanning electron microscopy images indicate the nanorod shape of as-prepared ZnTe with a diameter of 150-300 nm and length up to several micrometres. X-ray diffraction pattern confirms that the ZnTe nanorods have the cubic structure of zinc blende type with lattice parameter a = 6.111 Å. Thermo-gravimetric analysis and differential scanning calorimetry investigations reveal that neutral hydrazine and excess tellurium are directly intercalated into the ZnTe precursor framework and are decomposed during the thermal treatment. Absorption spectrum shows that as-synthesized ZnTe nanorods have an interband absorption at 543 nm (2.28 eV). Photoluminescence spectrum and fluorescent imaging of the products exhibit a visible light emission (at 558 nm).
Co-reporter:Yi Xi, Chenguo Hu, Puxian Gao, Rusen Yang, Xiaoshan He, Xue Wang, Buyong Wan
Materials Science and Engineering: B 2010 Volume 166(Issue 1) pp:113-117
Publication Date(Web):15 January 2010
DOI:10.1016/j.mseb.2009.10.008
CuxO (x = 1, 2) nanocrystals have been synthesized by the composite-hydroxide-mediated approach. The obtained nanocrystals were characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, scanning electron microscopy, transmission electron microscopy, and UV–vis spectrum. The morphology of the nanocrystals changed from sphere-shaped nanostructures to flower-shaped nanostructures, and finally to nanowires associated with phase transformation from CuO to Cu2O by increasing the temperature. The possible phase transformation mechanism was discussed. The catalytic degradation activity of the CuxO (x = 1, 2) nanocrystals to methyl orange was also investigated. The photocatalytic ability of the sphere-shaped nanostructures is much higher than that of the nanowires, owing to its absorption of wider range of light energy. This work provides a new facile synthesis route of CuxO (x = 1, 2) nanocrystals and suggests their possible application in organic pollutants removal.
Co-reporter:Chenguo Hu, Wei Yan, Buyong Wan, Kaiyou Zhang, Yan Zhang, Yongshu Tian
Physica E: Low-dimensional Systems and Nanostructures 2010 Volume 42(Issue 5) pp:1790-1794
Publication Date(Web):March 2010
DOI:10.1016/j.physe.2010.01.050
Single-crystalline CdSe nanostructures have been synthesized for the first time by the composite-hydroxide-mediated approach with a small amount of water. The phase transition of CdSe nanocrystals from zinc blende to wurtzite phase can be controlled by varying the water content and the morphologies of the CdSe nanocrystals are controlled simultaneously. The phase transition and morphology have been characterized by XRD, SEM and TEM. The phase transition critical points with respect to proper water content have been found at different temperatures. The phase transition and growth mechanism have been discussed. Optical band gaps of these two CdSe nanostructures have been investigated by an UV–vis spectrophotometer.
Co-reporter:Chuanhui Xia, Chenguo Hu, Yongshu Tian, Buyong Wan, Jing Xu, Xiaoshan He
Physica E: Low-dimensional Systems and Nanostructures 2010 Volume 42(Issue 8) pp:2086-2090
Publication Date(Web):June 2010
DOI:10.1016/j.physe.2010.04.003
Ni-doped ZnO rod arrays have grown on zinc foils by a hydrothermal method at 180 °C. The doping Ni content could be controlled by varying the reaction time. The characterization of the rod array with X-ray diffraction and X-ray photoelectron spectroscopy indicated that Ni2+ ions were incorporated into the ZnO lattices. Photoluminescence peak of the rod arrays shifts to a little longer wavelength and its intensity decreases with the increase in Ni content. The green light emission as a result of oxygen vacancies was observed when excessive Ni ions were doped in ZnO. The rod arrays have exhibited room-temperature ferromagnetic behavior with the remanence of 0.454, 0.605 and 0.526 emu/cm3 for the Ni concentration of 2.38, 4.35 and 5.54 at%, respectively. The exchange interaction between local spin-polarized electrons and conductive electrons was proposed as a cause of the room-temperature ferromagnetism.
Co-reporter:Yan Zhang, Chenguo Hu, Chunhua Zheng, Yi Xi and Buyong Wan
The Journal of Physical Chemistry C 2010 Volume 114(Issue 35) pp:14849-14853
Publication Date(Web):August 16, 2010
DOI:10.1021/jp105592d
Single crystalline Cu2−xSe nanowires with lengths up to 50 μm are synthesized via a modified composite hydroxide mediated method. Experiments reveal that both quantity and species of hydroxides or amount of water used in the preparation would affect final morphology of Cu2−xSe crystals, from nanoplates to nanorods to nanowires. The UV−visible−near-infrared reflection spectrum demonstrates the absorption edges of the Cu2−xSe nanowires in the ultraviolet and near-infrared region, which could be interpreted in terms of direct transitions from a band gap of 2.38 eV and indirect transitions from a band gap of 1.12 eV. The band-to-band transition model has been proposed. In addition, Seebeck effect based on the Cu2−xSe nanowire film is investigated, demonstrating the Seebeck coefficient of 180 μV/K.
Co-reporter:Yongshu Tian, Chenguo Hu, Yufeng Xiong, Buyong Wan, Chuanhui Xia, Xiaoshan He and Hong Liu
The Journal of Physical Chemistry C 2010 Volume 114(Issue 22) pp:10265-10269
Publication Date(Web):May 14, 2010
DOI:10.1021/jp911854n
We introduce a new type of ZnO array structure that can effectively suppress the reflection of light at a range of wavelength from ultraviolet through visible part to the near-infrared region, with reflectivity <2.5%, resulting in its black color. This black ZnO is composed of a random pyramidal array growing directly on Zn foil through a simple hydrothermal method. We have investigated the causes of antireflection by removing the pyramid tips via scratching and ion etching on the ZnO surface. All results demonstrate that the antireflection nature of the black ZnO originates from the pyramidal array structure, which causes a gradient change of refractive index between air and substrate.
Co-reporter:Buyong Wan;Hong Liu;Xueyan Chen;Yi Xi
Nanoscale Research Letters 2010 Volume 5( Issue 8) pp:
Publication Date(Web):2010 August
DOI:10.1007/s11671-010-9651-9
The lead tellurite nanobelts have been first synthesized in the composite molten salts (KNO3/LiNO3) method, which is cost-effective, one-step, easy to control, and performed at low-temperature and in ambient atmosphere. Scanning electron microscopy, X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectrum, energy dispersive X-ray spectroscopy and FT-IR spectrum are used to characterize the structure, morphology, and composition of the samples. The results show that the as-synthesized products are amorphous and glassy nanobelts with widths of 200–300 nm and lengths up to tens of microns and the atomic ratio of Pb:Te:O is close to 1:1.5:4. Thermo-gravimetric analysis (TGA) and differential scanning calorimetry (DSC) and investigations of the corresponding structure and morphology change confirm that the nanobelts have low glass transition temperature and thermal stability. Optical diffuse reflectance spectrum indicates that the lead tellurite nanobelts have two optical gaps at ca. 3.72 eV and 4.12 eV. Photoluminescence (PL) spectrum and fluorescence imaging of the products exhibit a blue emission (round 480 nm).
Co-reporter:Yongshu Tian, Chenguo Hu, Xiaoshan He, Chunlan Cao, Guangsheng Huang, Kaiyou Zhang
Sensors and Actuators B: Chemical 2010 Volume 144(Issue 1) pp:203-207
Publication Date(Web):29 January 2010
DOI:10.1016/j.snb.2009.10.065
Titania nanotube arrays were fabricated by anodic oxidation of titanium foil. The speed of electron transfer between the titania arrays and solution was measured by electrochemical impedance spectroscopy. High conductivity has been achieved by annealing the TNT arrays in air, much better than previously reported. The photocurrent performances in exposure to a simulated sunlight, tungsten lamp and fluorescent lamp have been investigated under 0 bias, indicating ∼ms response with advantages of high sensitivity and excellent heat stability. The device can effectively detect a trace UV light change and prevent from infrared/thermal influence in exposure to any light source containing UV, which promises a new type light sensor/switch for common light source including sunlight. In addition, the linear plot of photocurrent versus the incident light intensity (UV and simulated sunlight) indicates that the nanotube arrays can be used as a sensitive and stable UV photometer.
Co-reporter:Xue Wang, Chenguo Hu, Hong Liu, Guojun Du, Xiaoshan He, Yi Xi
Sensors and Actuators B: Chemical 2010 Volume 144(Issue 1) pp:220-225
Publication Date(Web):29 January 2010
DOI:10.1016/j.snb.2009.09.067
CuO flowers and nanorods have been synthesized for the first time by the composite-hydroxide-mediated and the composite-molten-salt method, respectively, with advantages of one-step, ambient pressure, low temperature, template-free and low cost. Both nanostructures have been applied to modify the graphite substrates for nonenzymatic glucose detection. Compared with bare graphite electrode, the new electrodes exhibit excellent catalysis to direct glucose oxidation. Though the electrode based on the CuO flowers has higher sensitivity than that of the CuO nanorods modified electrode, the latter presents a much better linear range of glucose concentration and a shorter response time. Both electrodes exhibit the same detection limit of glucose as low as 4 μM. In addition, the detection of dopamine and ascorbic acid has also been carried out on these CuO nanostructure modified electrodes, indicating good selectivity for glucose detection.
Co-reporter:Xiaoshan He, Chenguo Hu, Hong Liu, Guojun Du, Yi Xi, Youfei Jiang
Sensors and Actuators B: Chemical 2010 Volume 144(Issue 1) pp:289-294
Publication Date(Web):29 January 2010
DOI:10.1016/j.snb.2009.11.004
Co-reporter:Chuanhui Xia, Chenguo Hu, Peng Chen, Buyong Wan, Xiaoshan He, Yongshu Tian
Materials Research Bulletin 2010 45(7) pp: 794-798
Publication Date(Web):
DOI:10.1016/j.materresbull.2010.03.015
Co-reporter:Yi Xi, Chenguo Hu, Chunhua Zheng, Hulin Zhang, Rusen Yang, Yongshu Tian
Materials Research Bulletin 2010 45(10) pp: 1476-1480
Publication Date(Web):
DOI:10.1016/j.materresbull.2010.06.007
Co-reporter:Chenguo Hu, Yi Xi, Hong Liu and Zhong Lin Wang
Journal of Materials Chemistry A 2009 vol. 19(Issue 7) pp:858-868
Publication Date(Web):12 Jan 2009
DOI:10.1039/B816304A
The composite-hydroxide-mediated (CHM) method is based on the use of molten composite hydroxides as a solvent in chemical reactions at ∼200 °C for the synthesis of a wide range of nanostructures. This review focuses on its recent development with an emphasis on its applications for synthesizing materials of complex oxides, hydroxides, simple oxides, sulfides, selenides, tellurides, fluorides and metals. The principle of this synthesis method is introduced, and the key factors that affect the morphology and size are studied. The advantages of its low synthesis temperature, low pressure and low cost are illustrated through the synthesis of functional wires, rods, belts and other nanostructures.
Co-reporter:Yi Xi, Jinhui Song, Sheng Xu, Rusen Yang, Zhiyuan Gao, Chenguo Hu and Zhong Lin Wang
Journal of Materials Chemistry A 2009 vol. 19(Issue 48) pp:9260-9264
Publication Date(Web):29 Oct 2009
DOI:10.1039/B917525C
We present a systematic study of the growth of hexagonal ZnO nanotube arrays using a solution chemical method by varying the growth temperature (<100 °C), time and solution concentration. A piezoelectric nanogenerator using the as-grown ZnO nanotube arrays has been demonstrated for the first time. The nanogenerator gives an output voltage up to 35 mV. The detailed profile of the observed electric output is understood based on the calculated piezoelectric potential in the nanotube with consideration of the Schottky contact formed between the metal tip and the nanotube; and the mechanism agrees with that proposed for nanowire based nanogenerator. Our study shows that ZnO nanotubes can also be used for harvesting mechanical energy.
Co-reporter:Yi Xi, Chenguo Hu, Xiaomei Zhang, Yan Zhang, Zhong Lin Wang
Solid State Communications 2009 Volume 149(43–44) pp:1894-1896
Publication Date(Web):November 2009
DOI:10.1016/j.ssc.2009.08.003
Bismuth sulfide (Bi2S3) nanowires have been synthesized for the first time by a one-step, low temperature, ambient pressure, environment friendly molten salt solvent method. The photoelectric response of Bi2S3 nanowire films has been characterized in the visible light of different wavelengths and ultraviolet, and the results indicated its great potential applications as optical sensors/switches and optoelectronic nanodevices with a response time in ∼∼ms range.
Co-reporter:Zuwei Zhang 张张张 胡胡胡
Journal of Wuhan University of Technology-Mater. Sci. Ed. 2009 Volume 24( Issue 1) pp:
Publication Date(Web):2009 February
DOI:10.1007/s11595-009-1034-7
A novel method of direct synthesis of CeO2 nanoparticles onto multi-walled carbon nanotubes (MWNTs) was developed with advantages of simplicity, ease of scale-up, and low costs. The size of CeO2 particles deposited on the MWNTs was less than 6 nm. SEM and TEM were employed to analysis the CeO2 coated MWNTs, and the properties of FTIR spectrum and UV-vis absorption spectrum were investigated. The functional groups on the MWNTs obtained by nitric acid treatment play an important role on the deposition of the CeO2 particles. The carbon nanotubes possess broadened UV absorption function after being coated with CeO2 nanopartilces.
Co-reporter:Michao Zhang, Chenguo Hu, Hong Liu, Yufeng Xiong, Zuwei Zhang
Sensors and Actuators B: Chemical 2009 Volume 136(Issue 1) pp:128-132
Publication Date(Web):2 February 2009
DOI:10.1016/j.snb.2008.09.021
Perovskite niobate (BaNbO3) nanocubes have been synthesized for the first time by using the composite-hydroxide-mediated method. The products were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). Humidity sensors based on BaNbO3 nanocubes were fabricated. The responsiveness to humidity for static and dynamic testing proved the ultrasensitive properties of the sensors. The resistance changed from 932.4 MΩ to 2.2 MΩ as the relative humidity (RH) increases from 10% to 80%. The response-time and recovery-time of the resistance is 12 s and 32 s versus the changes of relative humidity from 20% to 60%. These results indicate promising applications of BaNbO3 nanocubes in a highly sensitive environmental monitoring and humidity controlled electronic device.
Co-reporter:Buyong Wan, Chenguo Hu, Bin Feng, Yi Xi, Xiaoshan He
Materials Science and Engineering: B 2009 Volume 163(Issue 1) pp:57-61
Publication Date(Web):25 June 2009
DOI:10.1016/j.mseb.2009.05.004
The pure face-centered cubic lead telluride nanorods and microcubes have been synthesized by the composite-hydroxide-mediated (CHM) approach using hydrazine and NaBH4 as a reducing agent, respectively. The method is based on reactants in hydroxide melts at a eutectic temperature of 200 °C and normal atmosphere without using an organic dispersant or surface capping agent. Scanning electron microscopy, X-ray diffraction, transmission electron microscopy, and energy dispersive X-ray spectroscopy are used to characterize the structure, morphology, and composition of the samples. The results show that the diameter of nanorods is 40–70 nm, while the size of microcubes is up to several micrometers. The measurement of thermoelectricity shows that the room temperature Seebeck coefficient value of the nanorods is up to 679.8 μV/K, about 2.56 times larger than that of the lead telluride bulk material, while the Seebeck coefficient value of the microcubes is only 195.5 μV/K.
Co-reporter:Wei Yan, Chenguo Hu, Yi Xi, Buyong Wan, Xiaoshan He, Michao Zhang, Yan Zhang
Materials Research Bulletin 2009 44(6) pp: 1205-1208
Publication Date(Web):
DOI:10.1016/j.materresbull.2009.01.012
Co-reporter:Buyong Wan, Chenguo Hu, Hong Liu, Yufeng Xiong, Feiyun Li, Yi Xi, Xiaoshan He
Materials Research Bulletin 2009 44(9) pp: 1846-1849
Publication Date(Web):
DOI:10.1016/j.materresbull.2009.05.016
Co-reporter:Xiaoshan He, Chenguo Hu, Yi Xi, Buyong Wan, Chuanhui Xia
Sensors and Actuators B: Chemical 2009 Volume 137(Issue 1) pp:62-66
Publication Date(Web):28 March 2009
DOI:10.1016/j.snb.2008.11.002
The BaTiO3 nanocubes are prepared directly on Ti foils through electroless deposition method in composite-hydroxide-melts. Amperometric sensors based on the BaTiO3 nanocubes have been fabricated simply. A trace hydrogen peroxide has been determined by the sensor, indicating a high sensitivity, selectivity and fast response speed for electrochemical detection on the BaTiO3 nanocubes. The sensor with cube size of 200 nm and BaTiO3 layer of 1 μm provides a response current of 116 μA cm−2 and response time of 4 s when each of 0.1 mM H2O2 is added into 0.1 M PBS at pH 7.4. The linear detection of hydrogen peroxide ranges from 5.0 × 10−7 M to 1.1 × 10−3 M (R = 0.999).
Co-reporter:Jing Miao, Chenguo Hu, Hong Liu, Yufeng Xiong
Materials Letters 2008 Volume 62(Issue 2) pp:235-238
Publication Date(Web):31 January 2008
DOI:10.1016/j.matlet.2007.05.009
Single crystalline BaTiO3 nanoparticles starting from BaCO3 and TiO2 have been synthesized by a composite-hydroxide-mediated method. The influence of reaction time and temperature was investigated systematically. The as-synthesized samples were characterized by XRD, SEM and TEM. The result showed that all BaTiO3 samples were cubic phase with size from 70 to100 nm under different reaction temperature (165–220 °C) and time (24–72 h); higher temperature and longer time clearly favored the increase of particle size. The widened FWHM in XRD and the peak blue shift in UV–vis absorption spectrum with the decrease of the nanocube size demonstrated the quantum size effect.
Co-reporter:Feiyun Li, Chenguo Hu, Yufeng Xiong, Buyong Wan, Wei Yan and Michao Zhang
The Journal of Physical Chemistry C 2008 Volume 112(Issue 41) pp:16130-16133
Publication Date(Web):2017-2-22
DOI:10.1021/jp804053c
Silver telluride nanowires have been synthesized by the composite-hydroxide-mediated (CHM) method at temperatures of 180−225 °C. The products were single-crystalline nanowires and monoclinic phase Ag2Te with a high purity. The reversible structural phase transition from monoclinic structure (β-Ag2Te) to face-centered cubic structure (α-Ag2Te) around 148/133 °C was observed during the heating/cooling process. The latent heat of the phase transition was calculated. The electrical resistance and thermal emf versus temperature were for the first time investigated on the Ag2Te nanowires. Abrupt changes of conductivity and Seebeck coefficient around the phase transition temperature were observed. The maximum Seebeck coefficient is ∼170 and ∼160 μV K−1 during the heating and cooling process, respectively, indicating a promising one-dimensional thermoelectric material as a building block to construct nanodevices.
Co-reporter:C.G. Hu, B. Feng, Y. Xi, Z.W. Zhang, N. Wang
Diamond and Related Materials 2007 Volume 16(Issue 11) pp:1988-1991
Publication Date(Web):November 2007
DOI:10.1016/j.diamond.2007.09.008
The covalent and noncovalent modification of carbon nanotubes were investigated by binding carboxyl group with ends of MWNTs and wrapping ssDNA around sidewall of SWNTs. The electrochemical voltammetric properties were measured by cyclic voltammetry on the working electrodes made from these two kinds of modified carbon nanotubes. The electrochemical detections of low level dopamine in the presence of excess of ascorbic acid were carried out in phosphate buffer solution. The results indicate that both carboxyl–MWNTs and ssDNA–SWNTs electrodes are good analytical electrodes for electrochemical detecting or sensing.
Co-reporter:C.L. Cao, C.G. Hu, Y.F. Xiong, X.Y. Han, Y. Xi, J. Miao
Diamond and Related Materials 2007 Volume 16(Issue 2) pp:388-392
Publication Date(Web):February 2007
DOI:10.1016/j.diamond.2006.07.008
The temperature dependence of piezoresistive effect on multi-walled carbon nanotube (MWNT) films is investigated. The gauge factor for pristine MWNT films and chemically treated MWNT films at 500 microstrain was found to be 46 and 75, respectively, at room temperature, but increased rapidly with temperature, exceeding that of polycrystalline silicon (30) at 35 °C. These findings suggest that the performance of carbon nanotube-based sensors may be significantly superior to that of polycrystalline silicon.
Co-reporter:C.G. Hu, W.L. Wang, K.J. Liao, G.B. Liu, Y.T. Wang
Journal of Physics and Chemistry of Solids 2004 Volume 65(Issue 10) pp:1731-1736
Publication Date(Web):October 2004
DOI:10.1016/j.jpcs.2004.04.009
The functionalization of carbon nanotubes (CNTs) was carried out by using different chemical treatment methods. These functionalized CNTs were characterized by TEM image and FT-IR spectra. The CNT electrodes are measured by thermal resistivity and cyclic voltammetry experiments. The results showed that two important factors controlled the electrochemical properties of the CNT film electrode: one is the active functional group; another is activation energy of the CNT film. From our experiments, we have found the electrode of 10 min nitric acid treated CNTs have the optimal peaks in relation to carboxylic acids, the highest redox peak currents, the biggest value of k0 and well-defined quasi-reversible voltammograms for redox of iron couples, in which the two factors best match.
Co-reporter:C.G. Hu, W.L. Wang, S.X. Wang, W. Zhu, Y. Li
Diamond and Related Materials 2003 Volume 12(Issue 8) pp:1295-1299
Publication Date(Web):August 2003
DOI:10.1016/S0925-9635(03)00071-2
The electrochemical behavior of carboxyl-modified carbon nanotube (CNT) films was investigated. The structure of the modified CNT was characterized by scanning electron microscopy, Raman spectroscopy and infrared spectroscopy. Experimental results showed that the physical structure of CNTs was not changed, but the ends of CNT were opened, and oxidized into carboxylate groups, which might react with other reagents. Cyclic voltammetry of Fe2+ was conducted in 0.2 M HClO4. A stable, quasi-reversible voltammetric response is seen for Fe3+/2+ at the carboxyl-modified CNT electrode, and the anodic and the cathodic peak potentials were 1.120 and 0.145 V vs. saturated calomel electrode at a scan rate of 0.15 V s−1, respectively. Both anodic and cathodic peak currents depended linearly on the square root of the scan rate over the range of 0.025–0.2 V s−1, which suggested that the process of the electrode reactions was diffusion-controlled. There were significant differences in voltammetry between the non-modified CNT surface and the carboxyl-modified CNT surface for Fe2+. The low level and stable detection of hydrazine was performed in a phosphate buffer pH 6.6. The peak current increased linearly with the hydrazine concentration from 0.01 to 1 mM and the concentration limit of quantitation was 0.01 mM. The results obtained are discussed in detail.
Co-reporter:Jie Chen, Hengyu Guo, Guanlin Liu, Xue Wang, Yi Xi, Muhammad Sufyan Javed, Chenguo Hu
Nano Energy (March 2017) Volume 33() pp:
Publication Date(Web):March 2017
DOI:10.1016/j.nanoen.2017.01.052
•The stator-free structure makes the device more facile to be installed on the rotation objects.•Combing TENG and EMG, the hybridized device can effectively harvest broad frequency band rotation energy.•TENG part would be stopped working when rotation speed rising to ~380 rpm due to the centrifugal force, which can largely improve the durability of the device.•Fully-enclosed structure makes the device capable of operating in harsh environment.•Demonstrated applications in wireless speedometer and thermo-hygrometer self-powered systems.Harvesting energies from surroundings to build up self-powered sensing systems is very useful in our daily life. In this work, we design a cylinder-like fully-packaged hybrid nanogenerator for harvesting vertical rotation energy in broad frequency band by utilizing a magnet rod as the trigger to drive contact-separation mode triboelectric nanogenerator (TENG), and by coupling magnet rod with copper coils to operate electromagnetic generator (EMG). The stator-free structure makes the device more facile to be installed on the rotation objects. The output performances of TENG and EMG under various rotation speeds are systematically studied and clearly demonstrated by installing the device on a balance car, which proves that TENG can be more effective for low-frequency (<2 Hz) energy scavenging and indicates the durability of the device can be largely enhanced with this structure design. In addition, the hybridized device is applied for harvesting wheel rotation energy from a car to drive wireless sensors for monitoring temperature, humidity, speed or even tire pressure simultaneously. This work presents a new platform of hybrid generators for harvesting rotation energy in broad frequency band and building up self-powered wireless sensing systems.We reported a cylinder-like fully-packaged hybrid nanogenerator for harvesting vertical rotation energy in broad frequency band and building up self-powered wireless systems. Utilizing a magnet rod as the trigger to drive CS-TENG can largely enhance the durability of the device and the stator free structure makes the device more facile to be installed on the rotation objects.
Co-reporter:Xiaoshan He, Chenguo Hu, Hong Liu
Catalysis Communications (15 November 2010) Volume 12(Issue 2) pp:100-104
Publication Date(Web):15 November 2010
DOI:10.1016/j.catcom.2010.08.020
A novel support of Na2Ti3O7 nanowires for Pt catalysts has been prepared and used for methanol and ethanol electrooxidation. The Na2Ti3O7 nanowires with typical length up to several tens of micrometers and the average diameter of about 200 nm are used as the 3D support for loading Pt nanoparticles. FESEM and TEM show that the Pt nanoparticles of about 8 to 10 nm in diameter are evenly distributed on the surface of Na2Ti3O7 nanowires. The electrochemical studies reveal that the catalytic activity of Pt/Na2Ti3O7 electrocatalyst is almost threefold higher than that of Pt/C electrocatalyst at the same loading of Pt.Na2Ti3O7 nanowires are used as the 3D support for loading Pt nanoparticles for electrooxidation of methanol and ethanol.Download full-size imageResearch highlights►The Na2Ti3O7 nanowires are used as three dimensional support for Pt nanoparticles distribution. ►The Pt/Na2Ti3O7 electrocatalyst displays better catalytic activity and stability for the alcohol electrooxidation in both acidic and alkaline media than the Pt/C electrocatalyst with the same Pt loading as a result of 3D catalysis.
Co-reporter:Qiang Leng, Hengyu Guo, Xianming He, Guanlin Liu, Yue Kang, Chenguo Hu and Yi Xi
Journal of Materials Chemistry A 2014 - vol. 2(Issue 45) pp:NaN19434-19434
Publication Date(Web):2014/10/17
DOI:10.1039/C4TA04137B
Triboelectric generators have attracted considerable attention due to their rapidly improved electromechanical conversion efficiency. It is a great challenge to design a triboelectric generator to enable practical and effective operations. In this paper, we present a flexible interdigital-electrodes-based triboelectric generator (FITG) for harvesting sliding and rotating mechanical energy. When a film of flexible interdigital electrodes is placed on a plane, it can be used for harvesting sliding energy. When the film of the flexible interdigital electrodes is rolled into a cylinder, it can be used for harvesting rotating energy. In sliding mode, the maximum open-circuit voltage, short-circuit current and peak power density reach up to 400 V, 120 μA (10 mA m−2) and 13 W m−2, respectively, under a sliding velocity of 3.95 m s−1, which can be used to light tens of light-emitting diodes (LEDs) and to charge a commercial capacitor to 7.2 V within 35 s. The FITG can harvest the mechanical energy of mouse operation and traditional printing. In rotating mode, the maximum output voltage of the generator reaches as high as 1020 V at a rotating speed of 240 rpm. The FITG with interdigital electrodes on a flexible substrate has the advantages of light weight, resistance to wear, multifunction and high output power.
Co-reporter:Chenguo Hu, Yi Xi, Hong Liu and Zhong Lin Wang
Journal of Materials Chemistry A 2009 - vol. 19(Issue 7) pp:NaN868-868
Publication Date(Web):2009/01/12
DOI:10.1039/B816304A
The composite-hydroxide-mediated (CHM) method is based on the use of molten composite hydroxides as a solvent in chemical reactions at ∼200 °C for the synthesis of a wide range of nanostructures. This review focuses on its recent development with an emphasis on its applications for synthesizing materials of complex oxides, hydroxides, simple oxides, sulfides, selenides, tellurides, fluorides and metals. The principle of this synthesis method is introduced, and the key factors that affect the morphology and size are studied. The advantages of its low synthesis temperature, low pressure and low cost are illustrated through the synthesis of functional wires, rods, belts and other nanostructures.
Co-reporter:Weina Xu, Shuge Dai, Xue Wang, Xianming He, Mingjun Wang, Yi Xi and Chenguo Hu
Journal of Materials Chemistry A 2015 - vol. 3(Issue 28) pp:NaN5785-5785
Publication Date(Web):2015/06/03
DOI:10.1039/C5TB00592B
A novel and exceptionally sensitive glucose biosensor based on nanorod-aggregated flower-like CuO grown on a carbon fiber fabric (CFF) is developed for glucose detection, which is prepared by a simple, fast and green hydrothermal method. The electron transfer resistance of the CuO/CFF electrode on the interface between the electrode and the electrolyte is as low as 12.79 Ω as evaluated by electrochemical impedance spectroscopy. A cyclic voltammetry study reveals that the CuO/CFF electrode displays an excellent electrocatalytic activity toward the direct oxidation of glucose. Besides, chronoamperometry demonstrates a high sensitivity of 6476.0 μA mM−1 cm−2 at an applied potential of 0.45 V (vs. Ag/AgCl), with a fast response time and a low detection limit of only 1.3 s and ∼0.27 μM, respectively. In addition, the glucose sensor has high reproducibility with a relative standard deviation (R.S.D.) of 1.53% over eight identically fabricated electrodes and long-term stability with a minimal sensitivity loss of ∼9.9% over a period of one month as well as excellent anti-interference ability. Importantly, the CuO–CFF composite has such good flexible characteristics and can be fabricated into flexible electrodes for application in various complicated circumstances. This work presents a new strategy to achieve highly sensitive glucose sensors with flexibility by growing glucose electroactive nanostructure materials directly on multichannels and highly conductive carbon fiber fabrics.
Co-reporter:Xiaoyan Li, Chenguo Hu, Xueliang Kang, Qiang Len, Yi Xi, Kaiyou Zhang and Hong Liu
Journal of Materials Chemistry A 2013 - vol. 1(Issue 44) pp:NaN13726-13726
Publication Date(Web):2013/09/19
DOI:10.1039/C3TA12706K
Advanced thermoelectric technology offers the potential to convert waste heat into useful electricity, and a mechanism of transmission-free methods for solid state cooling. A low thermal conductivity is a prerequisite for obtaining high efficiency thermoelectric materials. It is a challenge to achieve low thermal conductivity without simultaneously destroying the electric conductivity, for which a ‘phonon glass/liquid–electron crystal’ is proposed. To realize the phonon glass–electron crystal, a host–guest cage crystal system is considered, while to realize the phonon liquid–electron crystal, superionic conductivity is needed. Here we report a novel material, a KCu7−xS4 nanowire, which exhibits enhanced thermoelectric properties compared to the traditional chalcogenide Cu7S4 nanostructure. The presence of K ions not only forms a clathrate and a superionic fluid structure, which provides the phonon glass and liquid–electron crystal, but also adjusts the product to give a nanowire-like morphology. A low thermal conductivity and large Seebeck coefficient can be achieved when the nanowires are pressed into a bulk material. Higher electrical conductivity is also obtained below 420 K. In addition, the numerous grain boundaries, Cu deficiency and the orientated nanowires further increase the thermoelectric properties. The results indicate a new strategy to obtain high efficiency thermoelectric materials by introducing kalium into copper chalcogenides to form a new crystal structure with ‘phonon glass and liquid–electron crystal’ properties.
Co-reporter:Shuge Dai, Hengyu Guo, Mingjun Wang, Jianlin Liu, Guo Wang, Chenguo Hu and Yi Xi
Journal of Materials Chemistry A 2014 - vol. 2(Issue 46) pp:NaN19669-19669
Publication Date(Web):2014/10/22
DOI:10.1039/C4TA03442B
A highly flexible solid-state micro-supercapacitor based on a pen ink-carbon-fiber (Ink-CF) thread structure was fabricated with excellent electrochemical performance such as a high capacitance of 4.31 mF cm−2 and an energy density of 3.8 × 10−7 W h cm−2 at a power density of 5.6 × 10−6 W cm−2. This fabricated structure shows excellent characteristics such as lightweight, small volume, flexibility and portability. By integrating it with a triboelectric nanogenarator, the micro-supercapacitors could be charged and power 8 commercial LEDs, demonstrating its feasibility as an efficient storage component for self-powered micro/nanosystems.
Co-reporter:Qiang Leng, Lin Chen, Hengyu Guo, Jianlin Liu, Guanlin Liu, Chenguo Hu and Yi Xi
Journal of Materials Chemistry A 2014 - vol. 2(Issue 30) pp:NaN11947-11947
Publication Date(Web):2014/06/03
DOI:10.1039/C4TA01782J
Waste heat has been regarded as one of the most important renewable and green energy sources, and its widespread reclamation could help to reduce the negative impacts of global warming and the energy crisis. In this work, we designed a pyroelectric generator based on a polyvinylidene fluoride film for harvesting the heat energy from hot/cold water, which widely exists in industrial processes. To achieve practical application, the device simply contacts a hot flow and cold flow alternately. The output open-circuit voltage and short-circuit current reached a maximum of 192 V and 12 μA, respectively, under a temperature change of 80 °C. The output power density can reach 14 μW cm, which is a great improvement for thermoelectric devices. The prepared pyroelectric generator can drive 42 green light-emitting diodes or charge a commercial capacitor (100 μF) to 3.3 V in 90 s. This work provides a promising strategy for efficiently harvesting waste heat from water and presents significant progress in thermoelectric conversion technology.
Co-reporter:Hengyu Guo, Xianming He, Junwen Zhong, Qize Zhong, Qiang Leng, Chenguo Hu, Jie Chen, Li Tian, Yi Xi and Jun Zhou
Journal of Materials Chemistry A 2014 - vol. 2(Issue 7) pp:NaN2087-2087
Publication Date(Web):2013/11/19
DOI:10.1039/C3TA14421F
Harvesting airflow energy and light energy from the ambient environment to build a self-powered system is attractive and challenging work. In this article, an airflow-induced triboelectric nanogenerator (ATNG) has been fabricated that converts wind energy to alternating electricity. The mechanism of ATNG has also been illustrated. The performance of ATNGs with different sizes was studied, from which we discovered that the ATNG (size: 1 cm × 3 cm, electrode gap: 1.5 mm) could easily collect energy from a gentle wind (5.3 m s−1). Due to the relatively high alternating electricity frequency (179.5–1220.9 Hz), an approximately stable output power (of up to 1.5 mW) was obtained from the ATNG (size: 1 cm × 3 cm, electrode gap: 0.5 mm) with 8.35 μC of charge transferred per second. Meanwhile, the fabricated wind energy harvesting device was used to drive 46 commercial green light-emitting diodes (LEDs) connected in series and charge a 220 μF capacitor to 2.5 V over 50 s. When combined with a dye-sensitized solar cell (DSC), the device can individually and simultaneously harvest wind and light energy. This shows the potential applications of this ATNG in self-powered systems.
Co-reporter:Guanlin Liu, Weina Xu, Xiaona Xia, Haofei Shi and Chenguo Hu
Journal of Materials Chemistry A 2015 - vol. 3(Issue 42) pp:NaN21139-21139
Publication Date(Web):2015/09/08
DOI:10.1039/C5TA06438D
Triboelectric nanogenerators (TENG) that harvest energy from ambient environment have attracted great attention since they were first reported. However, the structures of TENGs working in the vertical contact-separation mode are considerably monotonous and energy loss cannot be avoided during the working process. In this study, we design a novel TENG, which is based on three elastic plates and one acryl board in the center with two identical steel plates on both sides, using which periodic contact/separation of the friction layers proceeds like Newton's cradle, except for the intermittent input of mechanical energy to overcome the electrostatic interaction on the charged friction layers. Such a lamination structure in the original contact mode can provide considerably higher energy conversion efficiency than that of the friction layers in the original separation mode. With this new design, the output current of the TENG is 5.7 times as much as that of a common contact/separation TENG and 2.3 times as much as that of a similar structure TENG without the use of elasticity. The maximum short-circuit current, open-circuit voltage and output power are 114 μA, 428 V, and 4.32 W m−2, respectively, which are strong enough to light more than one hundred commercial LED lights. In addition, the TENG was applied to a self-powered flashing clapping palm decorated by 29 LEDs, which might replace the fluorescence palms that are powered by the chemical reactions of a dye mixed solution, in the future.
Co-reporter:Muhammad Sufyan Javed, Jie Chen, Lin Chen, Yi Xi, Cuilin Zhang, Buyong Wan and Chenguo Hu
Journal of Materials Chemistry A 2016 - vol. 4(Issue 2) pp:NaN674-674
Publication Date(Web):2015/11/27
DOI:10.1039/C5TA08752J
Nowadays, it is essential for us to design and fabricate efficient and cost-effective electrode materials for energy conversion and storage systems. Nanostructures are remarkable electrode materials due to their high surface area and large number of active sites. Herein zinc sulfide (ZnS) nanospheres with large surface area are hydrothermally grown on a flexible carbon textile (CT). The specific area and porosity are analyzed in detail under different pressures. The electrode based on the ZnS assembled CT (ZnS-CT) exhibits a high capacitance of 747 F g−1 at a scan rate of 5 mV s−1 in the LiCl aqueous electrolyte. The ZnS-CT is directly used as the binder free electrode for the fabrication of the symmetric flexible full solid state supercapacitor. The ZnS-CT supercapacitor shows excellent electrochemical performance along with light weight, thinness and good flexibility. The ZnS-CT supercapacitor demonstrates good capacitive behavior with a high specific capacitance of 540 F g−1 (areal capacitance of 56.25 F cm−2) at a scan rate of 5 mV s−1 with good rate capability and excellent cycling stability (94.6% retention of initial capacitance after 5000 cycles) at a constant current density of 0.8 mA cm−2. A high energy density of 51 W h kg−1 at a power density of 205 W kg−1 is achieved, indicating excellent ion accessibility and charge storage ability. Furthermore, three charged supercapacitors connected in series can light 4 red color light emitting diodes (2.0 V, 15 mA) for 2 min. ZnS nanospheres with large specific surface area combined with flexible carbon textile substrate offer to be a promising material in energy storage devices with high energy.
Co-reporter:Muhammad Sufyan Javed, Cuiling Zhang, Lin Chen, Yi Xi and Chenguo Hu
Journal of Materials Chemistry A 2016 - vol. 4(Issue 22) pp:NaN8859-8859
Publication Date(Web):2016/05/09
DOI:10.1039/C6TA01893A
Binary metal oxides have been considered as promising electrode materials for high performance pseudocapacitors because they offer higher electrochemical activity than mono metal oxides. The rational design of binder free electrode architecture is an efficient solution to the further enhancement of the performance of electrochemical supercapacitors. Herein, we report the synthesis of a hierarchical mesoporous NiFe2O4 (NFO) nanocone forest directly growing on carbon textile with ultra-high surface area by the hydrothermal method. The NiFe2O4 nanocone forest on carbon textile (NFO-CT) was used as a binder free electrode that exhibited the high capacitance of 697 F g−1 at a scan rate of 5 mV s−1 and was further used for the fabrication of a symmetric solid state supercapacitor. The open space between hierarchical nanocones allows easy diffusion for electrolyte ions and the carbon textile ensures fast electron transfer that leads to the remarkable electrochemical performance. The NFO-CT solid state supercapacitor exhibited the high capacitance of 584 F g−1 at a scan rate of 5 mV s−1 and 93.57% capacitance retention after 10000 cycles with the advantages of being light weight, thin and having good flexibility. A high energy density of 54.9 W h kg−1 at a power density of 300 W kg−1 was achieved, indicating the excellent energy storage features. Furthermore, three charged supercapacitors in series can light 4 red colored LEDs (2 V, 15 mA) for 2 min.
Co-reporter:Yi Xi, Jinhui Song, Sheng Xu, Rusen Yang, Zhiyuan Gao, Chenguo Hu and Zhong Lin Wang
Journal of Materials Chemistry A 2009 - vol. 19(Issue 48) pp:NaN9264-9264
Publication Date(Web):2009/10/29
DOI:10.1039/B917525C
We present a systematic study of the growth of hexagonal ZnO nanotube arrays using a solution chemical method by varying the growth temperature (<100 °C), time and solution concentration. A piezoelectric nanogenerator using the as-grown ZnO nanotube arrays has been demonstrated for the first time. The nanogenerator gives an output voltage up to 35 mV. The detailed profile of the observed electric output is understood based on the calculated piezoelectric potential in the nanotube with consideration of the Schottky contact formed between the metal tip and the nanotube; and the mechanism agrees with that proposed for nanowire based nanogenerator. Our study shows that ZnO nanotubes can also be used for harvesting mechanical energy.
