Covalent Organic Frameworks Enhance Photocatalytic Hydrogen Peroxide Production through Synergistic Effects

Abstract

Covalent organic frameworks (COFs) are promising photocatalytic materials due to their high crystallinity, ordered porous structures, and customizable functionality. However, their photocatalytic performance is often hampered by challenges such as charge carrier recombination and suboptimal reactant adsorption. In this study, we aim to enhance the photocatalytic hydrogen peroxide production performance by introducing fluorine atoms into the pore walls of an imine-bonded COF, synthesizing two imine-bonded COFs: HITMS-COF-20 and HITMS-COF-21. The high electronegativity and small atomic size of fluorine atoms significantly improve light absorption, exciton delocalization, charge-carrier separation, and oxygen molecule adsorption. Analyses revealed that fluorine doping reduces charge recombination and enhances oxygen activation, thereby improving hydrogen peroxide production efficiency. These findings provide important insights into the mechanism of photocatalytic hydrogen peroxide production in COFs and offer pathways for the design of advanced photocatalysts for chemical synthesis.