Nitrogenase inspired artificial photosynthetic nitrogen fixation

Artificial photosynthetic nitrogen reduction reaction (photo-NRR) represents a more sustainable strategy beyond Haber-Bosch chemistry for N-2 fixation. Overcoming the kinetic challenges to activate insoluble and inert N-2 under ambient conditions for multi-electron and proton processes is the key to photo-NRR. Inspired by the effective N-2 fixation in nitrogenase, the elemental composition, structure, and electronics of FeMo-cofactor (FeMo-co) active center in MoFe protein have stimulated the exploration of artificial catalysts in homogeneous transition metal complexes and heterogeneous materials. To initiate effective solar-to-NH3 conversion, these catalysts should be intimately coupled with more specialized photosensitizers in proximity to guarantee continuous and unidirectional multi-electron transfer, and the catalytic environment should be better defined and optimized to modulate N-2 and proton transfer kinetics. In the next decade, photo-NRR will progress from proof-of-concept discoveries to more effective solar-to-chemical conversions, and the opportunity of implementing upgraded N-2-to-chemical conversions will also be presented by artificial photosynthesis.