Suppressing Water Dissociation via Control of Intrinsic Oxygen Defects for Awakening Solar H₂O‐to‐H₂O₂ Generation

BiVO₄ theoretically has a thermodynamic activity trend toward highly selective water oxidative H₂ O₂ formation, but it is more inclined to generate O₂ in practical. The influence of intrinsic oxygen vacancy (Ovac ), especially, on surface reactivity, has never been considered as a possible activity loss mechanism in the synthetic BiVO₄ . In this work, it is theoretically and experimentally demonstrated that the intrinsic surface Ovac is responsible for lower H₂ O₂ evolution activity via promoting water dissociation to form intermediate. Through an annealing process under a V₂ O₅ rich atmosphere, the surface Ovac can be eliminated that awakens the photoelectrochemical (PEC) water oxidative H₂ O₂ activity in a NaHCO₃ electrolyte, which achieves an average of 58.4%, and increases by up to 4.28 times of the one annealed in air. This work offers a general understanding of catalytic activity loss and may be extended to other photo or electrocatalysts for catalytic selectivity regulation.