Indium Oxide Layer Dual Functional Modified Bismuth Vanadate Photoanode Promotes Photoelectrochemical Oxidation of...

The photoelectrochemical (PEC) dual-electron pathway for water oxidation to produce hydrogen peroxide (H₂O₂) shows promising prospects. However, the dominance of the four-electron pathway leading to O₂ evolution competes with this reaction, severely limiting the efficiency of H₂O₂ production. Here, we report a In₂O₃ passivator-coated BiVO₄ (BVO) photoanode, which effectively enhances the selectivity and yield of H₂O₂ production via PEC water oxidation. Based on XPS spectra and DFT calculations, a heterojunction is formed between In₂O₃ and BVO, promoting the effective separation of interface and surface charges. More importantly, Mott-Schottky analysis and open-circuit potential measurements demonstrate that the In₂O₃ passivation layer on the BVO photoanode shifts the hole quasi-Fermi level towards the anodic direction, enhancing the oxidation level of holes. Additionally, the widening of the depletion layer and the flattening of the band bending on the In₂O₃-coated BVO photoanode favor the generation of H₂O₂ while suppressing the competitive O₂ evolution reaction. In addition, the coating of In₂O₃ can also inhibit the decomposition of H₂O₂ and improve the stability of the photoanode. This work provides new perspectives on regulating PEC two/four-electron transfer for selective H₂O₂ production via water oxidation.