Bismuth Vacancies Induced Lattice Strain in BiVO<sub>4</sub> Photoanodes Boosting Charge Separation For Water Oxidation
Boyan Liu, Xin Wang, Yingjuan Zhang, Kang Wan, Liangcheng Xu, Siqing Ma, Ruoting Zhao, Songcan Wang, Wei Huang
Abstract
Abstract Photoelectrochemical (PEC) water splitting is a promising technology for green hydrogen production. However, severe charge recombination in the photoelectrode materials is one of the key obstacles to achieving high performance. Herein, a BiVO₄ photoanode with lattice strain (Str‐BVO) is constructed by generating Bi vacancies to promote charge separation in the bulk. The optimized Str‐BVO photoanode achieves a photocurrent density of 6.20 mA cm⁻ 2 at 1.23 V versus the reversible hydrogen electrode under AM 1.5 G illumination, with an impressive charge separation efficiency close to 100%. Systematical experiments and density functional theory reveal that the surface Bi vacancies induced strain causes the distortion of a small number of VO 4 tetrahedra, which increases the antibonding state energy of most normal VO 4 tetrahedra and creates more electronic vacancy states, thereby significantly promoting electron–hole separation. By surface loading with a FeNiO x co‐catalyst, the photoanode exhibits excellent PEC water‐splitting performance and stability.