Selective Dinitrogen Electroreduction to Ammonia on Zn ₂ V ₂ O ₇ Pyrochlore

Electrochemical ammonia synthesis offers an efficient and carbon-free alternative to traditional nitrogen fixation, providing a high energy density and economical carrier for renewable energy. However, the process is challenged by the strong kinetic barriers of N2 activation, necessitating the development of highly efficient electrocatalysts. In this study, we investigate zinc pyrovanadate (Zn2V2O7), a pyrochlore oxide, as a promising electrocatalyst for the nitrogen reduction reaction. The robust pyrochlore framework, stabilized by zinc, ensures structural integrity of Zn2V2O7, while vanadium centers act as the active sites for the reduction of thermodynamically stable molecular nitrogen. Density functional theory simulations indicate a surface-hydrogenation-assisted alternative associative mechanism for N2 conversion. The formation of ammonia and key intermediates was confirmed by isotopic 15NH3 nuclear magnetic resonance studies and in situ attenuated total reflectance surface-enhanced infrared absorption spectroscopy. Zn2V2O7 demonstrated selective ammonia production, achieving a high faradaic efficiency (FE) of 76.5% and a yield rate of 101 μg h–1 mgcat–1 in 0.1 M Na2SO4 electrolyte. These results highlight the potential of Zn2V2O7 as an efficient electrocatalyst for ammonia synthesis.