Suppressing Water Dissociation via Control of Intrinsic Oxygen Defects for Awakening Solar H O-to-H O Generation.

BiVO theoretically has a thermodynamic activity trend toward highly selective water oxidative H O formation, but it is more inclined to generate O in practical. The influence of intrinsic oxygen vacancy (O ), especially, on surface reactivity, has never been considered as a possible activity loss mechanism in the synthetic BiVO . In this work, it is theoretically and experimentally demonstrated that the intrinsic surface O is responsible for lower H O evolution activity via promoting water dissociation to form intermediate. Through an annealing process under a V O rich atmosphere, the surface O can be eliminated that awakens the photoelectrochemical (PEC) water oxidative H O activity in a NaHCO 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.