Bioinspired Construction of Proton-Coupled Electron Transfer Pathways in Covalent Organic Frameworks for Enhanced Photosynthesis of Hydrogen Peroxide.

Abstract

Covalent organic frameworks (COFs) have emerged as promising photocatalysts for the artificial photosynthesis of hydrogen peroxide (H₂O₂), yet their practical application is hindered by limited photocatalytic efficiency. Herein, a bioinspired strategy is reported to enhance the photocatalytic performance of COFs by introducing an ortho-positioned arrangement of enol (OH) and imine (N) groups. Through rational molecular engineering, a concerted proton-coupled electron transfer (PCET) pathway is established, which facilitates the efficient separation and transfer of photoexcited charge carriers, thereby dramatically enhancing H₂O₂ production from water and oxygen. The TbDO COF, featuring the PCET pathway, demonstrates superior performance, achieving a remarkable H₂O₂ production rate of 7265 μmol g^-1 h^-1 in a nonsacrificial system, surpassing COFs with similar structure but lacking this pathway. This study advances the design of COFs and opens new avenues for sustainable solar-to-chemical energy conversion.