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A BiVO4 Photoanode with a VOx Layer Bearing Oxygen Vacancies Offers Improved Charge Transfer and Oxygen Evolution Kinetics in Photoelectrochemical Water Splitting |
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| Authors: | Boyan Liu Xin Wang Yingjuan Zhang Liangcheng Xu Tingsheng Wang Xiong Xiao Prof Songcan Wang Prof Lianzhou Wang Prof Wei Huang |
| Institution: | 1. Frontiers Science Center for Flexible Electronics, Xi'an Institute of Flexible Electronics (IFE), Xi'an Institute of Biomedical Materials & Engineering, Northwestern Polytechnical University, 127 West Youyi Road, Xi'an, 710072 China
Contribution: Formal analysis (lead), ?Investigation (lead), Methodology (equal), Writing - original draft (lead);2. Frontiers Science Center for Flexible Electronics, Xi'an Institute of Flexible Electronics (IFE), Xi'an Institute of Biomedical Materials & Engineering, Northwestern Polytechnical University, 127 West Youyi Road, Xi'an, 710072 China Contribution: Formal analysis (equal), ?Investigation (equal), Methodology (equal);3. Frontiers Science Center for Flexible Electronics, Xi'an Institute of Flexible Electronics (IFE), Xi'an Institute of Biomedical Materials & Engineering, Northwestern Polytechnical University, 127 West Youyi Road, Xi'an, 710072 China Contribution: ?Investigation (equal), Methodology (equal);4. Frontiers Science Center for Flexible Electronics, Xi'an Institute of Flexible Electronics (IFE), Xi'an Institute of Biomedical Materials & Engineering, Northwestern Polytechnical University, 127 West Youyi Road, Xi'an, 710072 China Contribution: ?Investigation (equal), Methodology (supporting);5. Frontiers Science Center for Flexible Electronics, Xi'an Institute of Flexible Electronics (IFE), Xi'an Institute of Biomedical Materials & Engineering, Northwestern Polytechnical University, 127 West Youyi Road, Xi'an, 710072 China Contribution: ?Investigation (supporting), Methodology (supporting);6. Frontiers Science Center for Flexible Electronics, Xi'an Institute of Flexible Electronics (IFE), Xi'an Institute of Biomedical Materials & Engineering, Northwestern Polytechnical University, 127 West Youyi Road, Xi'an, 710072 China;7. Nanomaterials Centre, School of Chemical Engineering and Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072 Australia |
| Abstract: | Sluggish oxygen evolution kinetics are one of the key limitations of bismuth vanadate (BiVO4) photoanodes for efficient photoelectrochemical (PEC) water splitting. To address this issue, we report a vanadium oxide (VOx) with enriched oxygen vacancies conformally grown on BiVO4 photoanodes by a simple photo-assisted electrodeposition process. The optimized BiVO4/VOx photoanode exhibits a photocurrent density of 6.29 mA cm?2 at 1.23 V versus the reversible hydrogen electrode under AM 1.5 G illumination, which is ca. 385 % as high as that of its pristine counterpart. A high charge-transfer efficiency of 96 % is achieved and stable PEC water splitting is realized, with a photocurrent retention rate of 88.3 % upon 40 h of testing. The excellent PEC performance is attributed to the presence of oxygen vacancies in VOx that forms undercoordinated sites, which strengthen the adsorption of water molecules onto the active sites and promote charge transfer during the oxygen evolution reaction. This work demonstrates the potential of vanadium-based catalysts for PEC water oxidation. |
| Keywords: | Bismuth Vanadate Oxygen Evolution Cocatalyst Oxygen Vacancy Solar Hydrogen Vanadium Oxide |