Constructing Intersecting Electron and Proton Transfer Channels in Covalent Organic Frameworks for Enhanced Photocatalytic H 2 O 2 Production

Insufficient separation of photogenerated charge carriers and slow proton transfer are two major factors limiting the efficiency of photocatalytic hydrogen peroxide (H2O2) production using covalent organic frameworks (COFs). Herein, we propose a strategy for anchoring sulfonic acid (-SO3H) groups on the COF-H skeleton to build intersecting internal electron transfer channels and external proton transfer channels to synergistically promote photocatalytic H2O2 production. Experimental results and theoretical calculations reveal that sulfonation establishes a build-in electric field within the COF skeleton, serving as effective electron transfer channels, while regulating the pore microenvironment of COFs to form high-speed proton transfer channels. More importantly, the intersections of electrons and protons at the -SO3H groups facilitate the proton-coupled electron transfer process. Consequently, the disulfonated COF-2SO3H exhibited a photocatalytic H2O2 production rate of 6327 μmol h−1 g−1 without sacrificial agents and oxygen aeration, which is 12.6 times that of COF-H and significantly higher compared to the reported values obtained for other COF photocatalysts under similar reaction conditions. This work provides mechanistic insights into photocatalytic H2O2 production and a rational design strategy for COF-based photocatalysts.