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 N 2 activation, necessitating the development of highly efficient electrocatalysts. In this study, we investigate zinc pyrovanadate (Zn 2 V 2 O 7 ), a pyrochlore oxide, as a promising electrocatalyst for the nitrogen reduction reaction. The robust pyrochlore framework, stabilized by zinc, ensures structural integrity of Zn 2 V 2 O 7, 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 N 2 conversion. The formation of ammonia and key intermediates was confirmed by isotopic 15 NH 3 nuclear magnetic resonance studies and in situ attenuated total reflectance surface-enhanced infrared absorption spectroscopy. Zn 2 V 2 O 7 demonstrated selective ammonia production, achieving a high faradaic efficiency (FE) of 76.5% and a yield rate of 101 μg h –1 mg cat –1 in 0.1 M Na 2 SO 4 electrolyte. These results highlight the potential of Zn 2 V 2 O 7 as an efficient electrocatalyst for ammonia synthesis.