Sacrificial-Agent-Triggered Mass Transfer Gating in Covalent Organic Framework for Hydrogen Peroxide Photocatalysis.

Abstract

Covalent organic framework (COF) photocatalysts for H₂O₂ production remain challenging by mass transport limitations and poor charge separation efficiency. Herein, a sacrificial agent-triggered mass-transfer gating (MTG) strategy is developed to reconfigure interfacial reaction for photocatalytic H₂O₂ generation via synthesized benzothiazole-COFs. This enables precise switching of the dominant photocatalytic mechanism between surface-confined directional charge transfer pathways and diffusion-dominated redox processes. Notably, benzyl alcohol (BA) enhances the mass transport and the catalytic site accessibility, scavenges photogenerated holes, and supplies protons for coupling reactions, thereby increasing the H₂O₂ yield of Tp-BTz COF to 100.9 mmol g^-1 h^-1 and achieving the outstanding photocatalytic performance reported to date. Both Tp-BTz COF and Tp-TTz COF demonstrate durably high H₂O₂ production efficiency even in the high-salinity seawater and municipal tap water systems. The generated H₂O₂ effectively degrades organic pollutants such as methyl orange (MO) and rhodamine B (RhB), demonstrating practical potential for wastewater treatment. The proposed gating strategy by introducing BA enables three synergistic functions: i) modulating interfacial reactions, ii) acting as a sacrificial agent to scavenge holes, and iii) supplying abundant protons (H⁺) for the oxygen reduction reaction (ORR) to facilitate the proton-coupled electron transfer. This approach establishes a generalizable paradigm for designing high-performance photocatalytic systems toward sustainable energy and environmental applications.