Theory-Guided Construction of the Unsaturated V–N₂ Site with Carbon Defects for Highly Selective Electrocatalytic Nitrogen Reduction

Renewable energy-driven, electrocatalytic nitrogen reduction reaction (NRR) is a promising strategy for ammonia synthesis. However, improving catalyst activity and selectivity under ambient conditions has long been challenging. In this work, we obtained the potential active V–N center through theoretical prediction and successfully constructed the associated V–N 2 /N 3 structure on N-doped carbon materials. Surprisingly, such a catalyst exhibits excellent electrocatalytic NRR performance. The V–N 2 catalyst affords a remarkably high faradaic efficiency of 76.53% and an NH 3 yield rate of 31.41 μg NH 3 h –1 mg Cat. –1 at −0.3 V vs RHE. The structural characterization and density functional theory (DFT) calculations verified that the high performance of the catalyst originates from the tuned d-band upon coordination with nitrogen, in line with the original design intention as derived theoretically. Indeed, the V–N 2 center with carbon defects enhances dinitrogen adsorption and charge transfer, thereby lowering the energy barriers to form the *NNH intermediates. Such a strategy as a rational design─controllable synthesis─theoretical verification may prove effective as well for other chemical processes.