Engineering covalent/metal-organic frameworks with single atoms toward artificial photocatalytic nitrogen fixation

The production of ammonia in a green, environmentally friendly, and sustainable way is crucial for human society. This perspective focuses on the combination of covalent/metal-organic framework (COF/MOF) substrates and single-atom catalysts to produce ammonia through artificial photocatalytic N2 fixation reactions. The single-atom catalysts demonstrate high activity toward N2 fixation due to the maximum atomic efficiency, while they are easy to aggregate. COFs/MOFs are crystalline and porous materials that offer suitable platforms to anchor single atoms. Furthermore, the photoelectrochemical properties and local coordination environments are precisely controlled by tuning the structures of COF/ MOF substrates, leading to high activity for the NH3 evolution. The recent progress of COF/MOF-supported single-atom catalysts for photocatalytic N2 fixation is well concluded. Future opportunities and perspectives are discussed for the further development of advanced photocatalytic N2 fixation catalysts to produce NH3.