Shedding light on covalent organic framework photocatalysts: concept, design strategies, and applications-a review

Covalent organic frameworks (COFs) have gained significant attention as photocatalysts due to their high crystallinity, tunable porosity, and exceptional optoelectronic properties, particularly their ability to absorb a broad range of visible light. This review provides a comprehensive analysis of the recent advancements in COF-based photocatalysts for solar energy conversion and environmental remediation. Fundamental benefits, including COF crystalline frameworks, effective light absorption, structural properties, charge carrier separation, and transport, chemical stability, tunable porosity are systematically discussed. The role of different linker chemistries, various morphologies and their influence on photocatalytic efficiency is discussed. Additionally, excellent design strategies for enhancing the photocatalytic performance of COFs, such as donor–acceptor interaction, functional group modifications, doping, and heterojunction formation are thoroughly examined. The applications of COF-based photocatalysts are explored in depth, covering water splitting for hydrogen production, CO₂ reduction, and the degradation of environmental pollutants. Finally, the review provides insights into challenges and emerging opportunities to inspire further innovation and accelerate the development of COF-based materials for sustainable solar energy conversion and environmental remediation.