Dual donor-acceptor covalent organic frameworks for hydrogen peroxide photosynthesis
Chencheng Qin, Xiaodong Wu, Lin Tang, Xiaohong Chen, Miao Li, Yi Mou, Bo Su, Sibo Wang, Chengyang Feng, Jiawei Liu, Xingzhong Yuan, Yanli Zhao, Hou Wang
Abstract
Abstract Constructing photocatalytically active and stable covalent organic frameworks containing both oxidative and reductive reaction centers remain a challenge. In this study, benzotrithiophene-based covalent organic frameworks with spatially separated redox centers are rationally designed for the photocatalytic production of hydrogen peroxide from water and oxygen without sacrificial agents. The triazine-containing framework demonstrates high selectivity for H 2 O 2 photogeneration, with a yield rate of 2111 μM h −1 (21.11 μmol h −1 and 1407 μmol g −1 h −1 ) and a solar-to-chemical conversion efficiency of 0.296%. Codirectional charge transfer and large energetic differences between linkages and linkers are verified in the double donor-acceptor structures of periodic frameworks. The active sites are mainly concentrated on the electron-acceptor fragments near the imine bond, which regulate the electron distribution of adjacent carbon atoms to optimally reduce the Gibbs free energy of O 2 * and OOH* intermediates during the formation of H 2 O 2 .