Jiayong Gan

Hydrogenated TiO2 nanotube arrays for supercapacitors.

We report a new and general strategy for improving the capacitive properties of TiO(2) materials for supercapacitors, involving the synthesis of hydrogenated TiO(2) nanotube arrays (NTAs). The hydrogenated TiO(2) (denoted as H-TiO(2)) were obtained by calcination of anodized TiO(2) NTAs in hydrogen atmosphere in a range of temperatures between 300 to 600 °C. The H-TiO(2) NTAs prepared at 400 °C yields the largest specific capacitance of 3.24 mF cm(-2) at a scan rate of 100 mV s(-1), which is 40 times higher than the capacitance obtained from air-annealed TiO(2) NTAs at the same conditions. Importantly, H-TiO(2) NTAs also show remarkable rate capability with 68% areal capacitance retained when the scan rate increase from 10 to 1000 mV s(-1), as well as outstanding long-term cycling stability with only 3.1% reduction of initial specific capacitance after 10,000 cycles. The prominent electrochemical capacitive properties of H-TiO(2) are attributed to the enhanced carrier density and increased density of hydroxyl group on TiO(2) surface, as a result of hydrogenation. Furthermore, we demonstrate that H-TiO(2) NTAs is a good scaffold to support MnO(2) nanoparticles. The capacitor electrodes made by electrochemical deposition of MnO(2) nanoparticles on H-TiO(2) NTAs achieve a remarkable specific capacitance of 912 F g(-1) at a scan rate of 10 mV s(-1) (based on the mass of MnO(2)). The ability to improve the capacitive properties of TiO(2) electrode materials should open up new opportunities for high-performance supercapacitors.

Oxygen vacancies promoting photoelectrochemical performance of In 2 O 3 nanocubes

This work reports a facile method for preparing the new photoactive In2O3 films as well as their implementation in photoelectrochemical (PEC) application. We firstly investigated the relationship between oxygen vacancies (VO) and PEC performance and revealed a rule between them. We found that the optimized In2O3−n sample yielded a photocurrent density up to 3.83 mA/cm2 in 1 M Na2SO4 solution under the solar illumination. It also gave efficiency as high as 75% over 400 nm in the incident-photon-to-current-conversion efficiency (IPCE) spectrum, which is the best value for an In2O3 photoanode reported. Moreover, the PEC performance of these films is enhanced as the VO increased and then decreased with further increasing VO. This two-side effect means VO can favor the photoelectron activation, or act as recombination centers to prohibit the generation of photocurrent. Making highly photoactive In2O3 nanostructures in this work will open up new opportunities in various areas.

Porous CeO2 nanowires/nanowire arrays: electrochemical synthesis and application in water treatment

Herein, we present a template- and surfactant-free electrochemical method for the fabrication of hierarchical porous CeO2 NWs and NWAs. These porous NWs/NWAs have diameters of 50–200 nm and lengths of up to several micrometres. Both the NWs and NWAs exhibit an excellent ability to remove Congo red in wastewater treatment.

Controllable synthesis of ZnxCd1-xS@ZnO core-shell nanorods with enhanced photocatalytic activity.

We report the synthesis of Zn(x)Cd(1-x)S@ZnO nanorod arrays via a facile two-step process and the implementation of these core-shell nanorods as an environmental friendly and recyclable photocatalyst for methyl orange degradation. The band gap of Zn(x)Cd(1-x)S@ZnO core-shell nanorods can be readily tunable by adjusting the ratio of Zn/Cd during the synthesis. These Zn(x)Cd(1-x)S@ZnO core-shell nanorods exhibit a high photocatalytic activity and good stability in the degradation of the methyl orange. Moreover, these films grown on FTO substrates make the collection and recycle of the photocatalyst easier. These findings may open new opportunities for the design of effective, stable, and easy-recyclable photocatalytic materials.

Hydrogen production from solar driven glucose oxidation over Ni(OH)2 functionalized electroreduced-TiO2 nanowire arrays

Herein, we demonstrated that solar driven glucose oxidation to produce hydrogen has been achieved on a functionalized TiO2 nanowire arrays photoanode without expensive metal catalyst loading. The Ni(OH)2 functionalized the electro-reduced TiO2 NWAs photoanode exhibits a much lower onset potential, substantially higher oxidation current density and good stability for glucose oxidation.

Vertically aligned In2O3 nanorods on FTO substrates for photoelectrochemical applications

Vertically aligned In2O3 nanorod arrays (NRAs) were obtained by annealing the as-prepared In(OH)3 precursors that grew directly on FTO substrates via a simple template-free electrochemical assembly process. The absorption edges of In2O3 NRAs show a red-shift to the visible region, and a remarkable photocurrent response under visible light illumination (λ ≥ 390 nm) in photoelectrochemical cells.

Room-temperature ferromagnetism in hierarchically branched MoO3 nanostructures

Hierarchically branched MoO3 nanostructures on Ti substrates were successfully prepared via a simple and controllable electrodeposition–heat-treatment method. XPS and Raman results indicate that these branched MoO3 nanostructures possess some oxygen vacancies. The magnetic measurements show the prepared branched MoO3 nanostructures exhibit ferromagnetic behaviour at room temperature. The observed room-temperature ferromagnetism can be mainly ascribed to the oxygen vacancies on the surface of the samples.

Hierarchical CeO2 nanospheres as highly-efficient adsorbents for dye removal

Herein, we reported a facile electrochemical method to prepare hierarchical porous CeO2 nanospheres and their implementation as highly-efficient absorbents in removing organic dyes. These hierarchical CeO2 nanospheres constructed of numerous nanocrystallites exhibit excellent performance in removing Congo red. The adsorption capacity at 60 min reached 942.7 mg g−1.

Plasmon-enhanced nanoporous BiVO4 photoanodes for efficient photoelectrochemical water oxidation.

Conversion of solar irradiation into chemical fuels such as hydrogen with the use of a photoelectrochemical (PEC) cell is an attractive strategy for green energy. The promising technique of incorporating metal nanoparticles (NPs) in the photoelectrodes is being explored to enhance the performance of the photoelectrodes. In this work, we developed Au-NPs-functionalized nanoporous BiVO4 photoanodes, and utilized the plasmonic effects of Au NPs to enhance the photoresponse. The plasmonic enhancement leads to an AM 1.5 photocurrent of 5.1 ± 0.1 mA cm(-2) at 1.23 V versus a reverse hydrogen electrode. We observed an enhancement of five times with respect to pristine BiVO4 in the photocurrent with long-term stability and high energy-conversion efficiency. The overall performance enhancement is attributed to the synergy between the nanoporous architecture of BiVO4 and the plasmonic effects of Au NPs. Our further study reveals that the commendable photoactivity arises from the different plasmonic effects and co-catalyst effects of Au NPs.