Recent advance in metal- and covalent-organic framework-based photocatalysis for hydrogen evolution

The development of highly efficient solar energy–driven photocatalysts for hydrogen evolution reaction (HER) is critical to promoting hydrogen-powered technologies in the future. Metal organic frameworks (MOFs) and covalent organic frameworks (COFs) are a kind of crystal material with regular channels, ultra-high surface areas, and tunable chemical components, which provide fascinating functionalities in photocatalytic hydrogen production, by reducing reaction potentials, and accelerating reaction rates. Although some progresses have been gained in this field, basic issues remain to be solved to further comprehend the relationship between the structures, properties, and photocatalytic performance of MOF- and COF-based materials. Herein, the current state-of-the-art in the use of original MOFs and COFs, MOF- and COF-supported, and MOF-derived materials as photocatalysts to produce sustainable hydrogen energy are summarized. It begins with the principles of photocatalytic water splitting and the relevant factors to ascertain the catalytic activity. Following that, particular emphasis is placed in the novel strategies to enhance the photocatalytic performances. Furthermore, the structure−function correlation and applications of MOF- and COF-based photocatalysts are detailed in photocatalytic hydrogen production. Finally, an overview on the prospect and challenges of MOF- and COF-based photocatalysts in the field of photocatalytic hydrogen evolution is presented.