Deciphering the Working Mechanisms of Fe, Mo, and V Sites in Nitrogenases

Deciphering the working mechanism of natural nitrogenases is significant in inspiring the design of high-performance artificial systems for ambient-condition ammonia synthesis, while disclosing the roles of Fe, V, and Mo centers in cofactors is crucial but remains challenging. Here, we reported a biomimetic strategy and investigated the ammonia synthesis mechanism in nitrogenase-inspired bimetallic systems within the FER zeolite, serving as structural and functional analogs of nitrogenase cofactors. Our results identified an elegant correlation between H 2 evolution and the availability of “opened” Fe sites in both bioinspired and biological systems, thereby elucidating why Fe-, V-, and Mo-nitrogenases inevitably release 7, 3, and 1 H 2 molecules per N 2 reduction. Notably, the identified trend in ammonia synthesis activity among the bio-inspired systems (Fe-Fe < Fe-V < Fe-Mo < V-V < Mo-V < Mo-Mo) not only analogizes to the evolutionary adaptation of available nitrogenases but also provides a rationale for the design of more efficient nitrogenases.