MoO3/BiVO4 heterojunction film with oxygen vacancies for efficient and stable photoelectrochemical water oxidation
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Poor charge transfer and separation rate are the major bottlenecks for the activity and stability of BiVO4 photoanode. Here, we introduced oxygen vacancies into MoO3/BiVO4 heterojunction film by post-annealing the film in argon-saturated environment for improving its photoelectrochemical (PEC) water oxidation activity and stability. In comparison with the normal MoO3/BiVO4 film, the MoO3/BiVO4 film with oxygen vacancies is of better PEC water oxidation performance. Specifically, a higher photocurrent density of 4.1 mA/cm2 in 0.1 M Na2SO4 at 1.1 V versus SCE was achieved on the MoO3/BiVO4 film with oxygen vacancies, which is about 200% improved over the normal MoO3/BiVO4 film (1.83 mA cm−2, at 1.1 V versus SCE). In addition, the MoO3/BiVO4 film with oxygen vacancies shows more stable activity and faster kinetics for water oxidation, without significant activity loss for 5 h reaction at 1.23 V versus RHE. The enhanced performance on such a MoO3/BiVO4 film photoanode can be attributed to that the oxygen vacancies accelerate the charge transfer and separation rate between film/electrolyte interface, and thus improve the water oxidation activity and restrain the anodic photocorrosion simultaneously.
The authors acknowledge National Basic Research Program of China (973 Program: 2014CB846003), National Natural Science Foundation of China (41702037), Sichuan Science and Technology Program (2017JY0146 and 2018JY0462), Research Fund of Southwest University of Science and Technology (15zx7104 and 15zx7123).
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Conflicts of interest
The authors declare that they have no conflicts of interest.
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