Recent Progress on Covalent Organic Frameworks for Overall Photocatalytic Hydrogen Peroxide Production

The utilization of solar energy to convert water (H2O) and oxygen (O2) into hydrogen peroxide (H2O2) through artificial photosynthesis has recently emerged as a highly promising and environmentally friendly approach, as it relies solely on sunlight as the energy input. Covalent organic frameworks (COFs), owing to their unique structural and functional advantages, have demonstrated significant potential in solar-driven H2O2 production. COFs possess a highly ordered crystalline structure, tunable porosity, excellent thermal and chemical stability, and versatile molecular design capabilities. These properties enable precise regulation of light absorption, electron transfer, and reaction pathways, thereby facilitating efficient charge carrier separation and migration in photocatalytic H2O2 production. In recent years, numerous COF-based photocatalysts have achieved remarkable progress in H2O2 synthesis. To push COF-based photocatalysts for practical application, there is an urgent need to improve the performance of artificial photosynthesis of H2O2. In this review, we initially introduce the progress of COFs in overall photosynthesis of H2O2 and discuss the reaction pathways toward overall photosynthesis of H2O2. Subsequently, we summarize recent advances in photocatalytic H2O2 production using COFs materials under sacrificial-agent-free conditions, with only H2O and O2 as feedstocks, focusing on six key strategies: introduction of functional groups, construction of donor–acceptor (D–A) structures, isomerization, incorporation of redox-active units, postfunctionalization, and design of different types of COFs for dual-pathway applications in coupling the oxygen reduction reaction (ORR) and water oxidation reaction (WOR). Furthermore, we provide prospects and the major challenges currently faced in COF-based photocatalytic H2O2 synthesis, including the need for further enhancement of photocatalytic efficiency, optimization of stability, and mechanistic insights.