Water splitting catalysts using non-metal covalent organic frameworks: A review

Hydrogen (H2) production is essential for establishing a sustainable global ecosystem. Due to the availability of carbon-free resources, synthesizing H2 gas from water is currently attracting substantial attention worldwide. Covalent organic frameworks (COFs) are interesting materials for catalysis because they produce H2 when water is split. Compared to other organic polymers, COFs have higher surface areas, are simpler to functionalize, and exhibit more variety due to the formation of atomic covalent bonds. Therefore, COFs might be considered for hydrogen generation by electrocatalysis or photocatalysis. This review discusses the design factor of COF materials from the viewpoint of H2 production in water splitting; various linkage units, such as electron donor-acceptor and electron transfer mediator, are reviewed. Additionally, several synthetic routes and COFs challenges are briefly summarized. Finally, we provide an overview of COFs and their potential for practical applications in the electrocatalytic and photocatalytic production of H2 for the development of green energy.