Efficient Ambient Electrosynthesis of Ammonia over a Vanadium-Doped MnO₂ Catalyst

Ammonia serves as an ideal hydrogen energy carrier due to its safe transportability and potential as a renewable, zero-carbon fuel. The electrochemical nitrogen reduction reaction (eNRR) in aqueous electrolytes under ambient conditions, powered by renewable energy sources, represents a sustainable pathway. To maximize process efficiency, catalyst design must prioritize selective N₂ adsorption while effectively suppressing the competing hydrogen evolution reaction (HER). Building upon theoretical and experimental evidence that transition metals with unoccupied d-orbitals facilitate N₂ adsorption and inert bond activation, we developed vanadium-doped manganese oxide electrocatalysts for ambient-condition ammonia synthesis. The optimized V-MnO₂(0.2) catalyst exhibits exceptional performance, delivering an NH₃ yield rate of 14.5 μg h^{- 1} mg_cat ^{- 1} and a Faradaic efficiency of 17.3% at -0.4 V vs RHE (28% at -0.3 V). This work provides fundamental insights into electronic structure modulation via transition metal doping, active site engineering for selective N₂ adsorption, and design principles for noble-metal-free NRR catalysts.