Effective Strategies in Covalent Organic Frameworks for Enhanced Photocatalytic Hydrogen Production

Hydrogen as a significant green energy source, has emerged as one of the most promising candidates to solve serious environmental and energy problems. Photocatalytic water splitting is a prospective route to sustainable hydrogen production. Covalent organic frameworks (COFs) are considered as efficient photocatalysts due to their substantial specific surface areas, extended pi-conjugated backbones, and robust chemical stability. This review summarizes the recent advances of COF-based materials in the field of photocatalytic hydrogen production, including the construction of donor-acceptor (D-A) structure, protonation of the N site, synthesis of zwitterionic COFs, introduction of co-catalysts, use of metal-containing monomers, and compositing COFs with other catalysts. The properties of the catalysts are meticulously adjusted through those structural and system design strategies, thereby significantly enhancing the hydrogen production performance of the COFs. Finally, the challenges and potential opportunities for future developments are discussed in terms of the current research status and practical applications of photocatalytic hydrogen production from COFs.