Single Zn Atoms with Acetate‐Anion‐Enabled Asymmetric Coordination for Efficient H<sub>2</sub>O<sub>2</sub> Photosynthesis
Yunxiang Li, Yan Guo, Guilan Fan, Deyan Luan, Xiaojun Gu, Xiong Wen Lou
Abstract
Abstract Exploring unique single‐atom sites capable of efficiently reducing O 2 to H 2 O 2 while being inert to H 2 O 2 decomposition under light conditions is significant for H 2 O 2 photosynthesis, but it remains challenging. Herein, we report the facile design and fabrication of polymeric carbon nitride (CN) decorated with single‐Zn sites that have tailorable local coordination environments, which is enabled by utilizing different Zn salt anions. Specifically, the O atom from acetate (OAc) anion participates in the coordination of single‐Zn sites on CN, forming asymmetric Zn−N 3 O moiety on CN (denoted as CN/Zn−OAc), in contrast to the obtained Zn−N 4 sites when sulfate (SO 4 ) is adopted (CN/Zn−SO 4 ). Both experimental and theoretical investigations demonstrate that the Zn−N 3 O moiety exhibits higher intrinsic activity for O 2 reduction to H 2 O 2 than the Zn−N 4 moiety. This is attributed to the asymmetric N/O coordination, which promotes the adsorption of O 2 and the formation of the key intermediate *OOH on Zn sites due to their modulated electronic structure. Moreover, it is inactive for H 2 O 2 decomposition under both dark and light conditions. As a result, the optimized CN/Zn−OAc catalyst exhibits significantly improved photocatalytic H 2 O 2 production activity under visible light irradiation.