Pyridyl‐Imine‐Functionalized Donor–Acceptor Covalent Organic Frameworks for Optimal Photosynthesis of Hydrogen Peroxide

Abstract The artificial photosynthesis of hydrogen peroxide (H 2 O 2 ) using semiconductor photocatalysts is gaining attention as an eco‐friendly and energy‐efficient method. Covalent organic frameworks (COFs) show great promise in enhancing photocatalytic H 2 O 2 production due to their tunable structures and functional diversity. However, the efficiency of H 2 O 2 generation is close to the photoelectric properties of COFs and the microenvironment of their active sites. Herein, the synthesis of pyridyl‐imine‐functionalized COFs (PyIm‐COFs) featuring donor–acceptor (D–A) moieties to improve H 2 O 2 production efficiency is reported. By employing benzothiadiazole (BT) units with varied fluorine substitutions, the electronic environment of the active sites, optimizing the selective two‐electron (2e − ) oxygen reduction reaction (ORR), is tuned. Among the synthesized COFs, PyIm‐BT_F exhibits the highest photocatalytic activity, achieving a H 2 O 2 production rate of 5342 µmol g −1 h −1 . The importance of D–A moieties in the rational design of COF‐based photocatalysts, providing a novel strategy for sustainable H 2 O 2 production through optimized active site environments, is underscored.