Directional Concerted Proton‐Electron Transfer in COFs for Efficient Photocatalytic H ₂ O ₂ Production

Abstract

ABSTRACT Photocatalytic two‐electron oxygen reduction reaction (2e − ORR) offers a sustainable route for green H 2 O 2 synthesis. However, its efficiency is fundamentally constrained by the kinetic mismatch between proton transfer and electron migration across heterogeneous interfaces. Inspired by concerted proton–electron translocation in natural hydrogenases, we report a catechol–triazine donor–acceptor (D–A) covalent organic framework, 2,3‐Dhta‐Tt, for directional concerted proton–electron transfer (DCPET) during photocatalytic H 2 O 2 production. The intrinsic built‐in electric field, combined with a catechol‐derived dynamic proton‐relay network, aligns proton and electron fluxes and establishes a periodic co‐transport channel toward triazine acceptor sites. At the molecular level, the catechol donor units dominate the highest occupied molecular orbital (HOMO), acting simultaneously as photoexcitation centers and initial proton‐release sites, thereby synchronizing proton delivery with electron migration. This vectorial coupling lowers the activation barrier for O─O hydrogenation and promotes highly selective 2e − ORR, affording an H 2 O 2 production rate of 27.22 mmol g −1  h −1 in pure water. The framework also exhibits proton conductivity of 6.09 × 10 −5  S cm −1 and an extended excited‐state lifetime of 94.45 ps. Isotope labeling, operando spectroscopy, and DFT calculations support a proton‐cycling process and directional proton/electron participation. This work advances heterogeneous photocatalyst design beyond conventional PCET cooperativity.