Bisite Sulfonate‐Functionalized Covalent Organic Frameworks with Efficient and Dynamic Proton Transportation for Accelerating H <sub>2</sub> O <sub>2</sub> Photosynthesis
Kai-Cheng Yang, Li Chen, Kun Xiong, Jiani Yang, Mohsen Adeli, Shuang Li, Mao Wang, Chong Cheng, Changsheng Zhao
Abstract
Abstract Photocatalytic hydrogen peroxide (H 2 O 2 ) production using covalent organic frameworks (COFs) relies on the concerted operation of two half‐reactions: oxygen reduction (ORR) and water oxidation (WOR). A critical limitation arises from the frequent proton and O 2 supply‐demand imbalance between these processes, which constrains overall H 2 O 2 yields. To address this challenge, a bisite sulfonate‐functionalized COF (2‐SO 3 H‐COF) is developed that serves as an efficient proton mediator, promoting both solution‐phase proton/O 2 uptake and rapid intraframework proton transport through hopping mechanisms. The optimized material demonstrates remarkable performance, yielding 4744 µmol g −1 h −1 H 2 O 2 under acidic conditions (pH = 1) and even achieving 11 470 µmol g −1 h −1 in 10% benzyl alcohol solution, which represents a 3.36‐fold enhancement over unmodified COFs in deionized water. Isotopic labeling and computational studies elucidate how ‐SO 3 H groups facilitate proton conduction from water into the framework while enhancing O 2 adsorption, thereby promoting a direct 2e − ORR pathway. When implemented in a flow reactor system, 2‐SO 3 H‐COF enables continuous H 2 O 2 production while simultaneously degrading >95% of organic dyes and maintaining 99% antibacterial efficacy. These findings establish a general design principle for proton‐regulating photocatalysts and expand the potential of COF materials for sustainable chemistry and environmental applications.