Asymmetric p-π Conjugation Driven Charge Separation and Structural Regulation In Triazine-Cored COF for Hydrogen Peroxide Photosynthesis

Currently, as energy and environmental issues become increasingly prominent, efficient and green chemical synthesis technologies have emerged as a key research priority. The photocatalytic synthesis of hydrogen peroxide (H2O2) has attracted widespread attention due to its ability to utilize clean energy and operate under mild reaction conditions. Covalent organic frameworks (COFs) exhibit significant application potential in this field; however, optimizing the efficiency and selectivity of H2O2 synthesis through skeleton design remains a critical issue that urgently needs to be addressed. In this study, three imine-linked COFs with asymmetric p-π conjugated structures were constructed, namely TAPA-TFPT (triazine core), TAPA-TFPA (triarylamine core), and TAPA-TFPB (benzene core), and their photocatalytic performances were comparatively analyzed. Under sacrificial agent-free conditions, the three COFs generated H2O2 via either the 2e– ORR pathway or the two-step 1e– ORR pathway. Among them, TAPA-TFPT exhibited the best performance, with a photocatalytic yield of 0.96 mmol g–1 h–1. The study indicated that the triazine-core skeleton can promote the separation and transfer of charge carriers, which is the key to enhancing catalytic performance. This strategy provides important references for the photocatalytic preparation of H2O2 under sacrificial agent-free conditions.