Three‐Component COFs with D−π−A Units and Side‐Chain‐Enhanced Mass Transfer Enable Efficient Sacrificial‐Agent‐Free H <sub>2</sub> O <sub>2</sub> Photosynthesis
Yuesheng Han, Yucheng Jin, Xu Ding, Xiaolin Ma, Tianyu Wang, Houhe Pan, Dongdong Qi, Jianzhuang Jiang
Abstract
Abstract Photocatalytic oxygen reduction reactions (ORR) and water oxidation reactions (WOR) based on covalent organic frameworks (COFs) represent the most promising green approach for producing H 2 O 2 . However, the enhancement of COFs' photocatalytic efficiency is hindered by the challenge of optimally organizing both donor−acceptor (D−A) units and functional ligands. Herein, three−component COFs with D−π−A units and side chains are designed for achieving higher charge separation efficiency and mass transfer enhancement during photocatalysis. Precisely assembled donor (triphenylamine (TN)) and acceptor (triazine (TA)) in COFs form D−π−A units, in which WOR on TN units can carry out cooperatively with ORR on TA units. The thioether chains within COFs render the formation of gas/liquid/solid three−phase interfaces, which accelerate the oxygen diffusion for ORR. Thus, three−component COFs (TBT−COF) with thioether chains (R 2 S) can reach 7427.25 µmol g −1 h −1 for photocatalytic hydrogen peroxide generation without any sacrificing reagents. The synergy of D−π−A units and mass transfer enhanced by side chains plays very important role in achieving efficient photocatalysis via cooperative ORR/WOR pathways. These results open new possibilities for the fabrication of high−performance COFs‐based photocatalyst.