Oxygen Vacancy‐Driven Asymmetrical Charge Distribution on Bi‐O‐Sn Sites in Sn‐Doped Bi <sub>2</sub> MoO <sub>6</sub> for Efficient Photocatalytic CO <sub>2</sub> ‐to‐CH <sub>4</sub> Conversion
Qian Liang, Jingshan Fan, Xiuzheng Deng, Jiangchuan Liu, Jianrong Zeng, Hui Zhang, Jing Li, Changhai Liu, Zhenhui Kang, Zhen Zhao
Abstract
Abstract Efficient proton‐coupled electron transfer (PCET) at tailored active sites is beneficial for photocatalytic CO 2 reduction, yet the relationship between catalytic sites and performance remains unclear. Herein, p ‐block Sn is introduced into the Bi 2 MoO 6 lattice (Sn‐BMO) via Bi site substitution to construct a novel oxygen vacancy (Ov)‐Bi‐O‐Sn structure, where high‐valence Sn induces Ov formation by lowering the Bi valence state, thereby creating a charge‐asymmetrical region. This unique configuration promotes PCET: Sn acts as H 2 O oxidation site, enabling proton transfer to proximal Bi site connected to Ov that preferentially traps electrons to convert CO 2 . Furthermore, the electronic structure of Bi is modified to optimize Bi 6 p ‐C 2 p hybridization for formation of the key intermediate *CHO with low energy barrier. Consequently, Sn‐BMO exhibits a remarkable CH 4 evolution rate of 207.3 µmol g −1 h −1 with 95.7% CH 4 selectivity in pure water, achieving a record apparent quantum efficiency of 9.4% at 420 nm. This work provides a novel approach to design charge‐asymmetrical active site in multisite catalysts, elucidating how p ‐block elements influence catalytic performance in CO 2 photoreduction.