Covalent Organic Framework-Based Photocatalysts from Synthesis to Applications

Covalent organic frameworks have emerged as a hot spot in the field of photocatalysis due to their excellent structural tunability, high specific surface area, high porosity, and good chemical stability. Specifically, they exhibit distinctive optoelectronic features by integrating different molecular building blocks with appropriate links, constructing an π-conjugated system, or introducing electron donor–acceptor units into the conjugated framework. The reasonably adjusted band structure yields excellent photocatalytic activity of covalent organic framework materials. In this review, we comprehensively focus on applications of covalent organic framework materials as effective photocatalysts within the realm of hydrogen production, CO₂ reduction, pollutant degradation, organic conversion and other aspects. The discussion encompasses synthesis methods and reaction types of covalent organic frameworks. This review also discusses the state-of-the-art research progress, performance optimization strategies and the diverse manifestations of covalent organic framework materials used in photocatalysis. Finally, the main challenges and prospects aimed at further improving the photocatalytic performance of covalent organic frameworks are briefly proposed. By giving us a thorough understanding of the structural complexities of covalent organic frameworks and their essential role in photocatalytic processes, this effort advances our understanding and serves as a guide for the future design and development of novel covalent organic frameworks.