NiO-Incorporated Cu/CuO Nanowires for Highly Efficient Electrochemical Nitrate Reduction to Ammonia.

Electrochemical nitrate reduction to ammonia (NRA) is a promising sustainable way to synthesize ammonia (NH) from nitrate (NO ) contaminants. Cu-based electrocatalysts are frequently utilized for NRA due to their strong NO adsorption and de-oxygenation ability. However, this kind of catalyst usually possesses the weak water dissociation ability, resulting in insufficient proton supply in alkaline media to retard the following hydrogenation step of O-containing intermediates (*NO, typically NO ) to target NH. Herein, NiO-incorporated Cu/CuO nanowires grown on nickel foam (p-CuNi@NF, p refers to plasma treatment) were synthesized via hydrothermal growth and subsequent O plasma treatment for efficient NRA electrocatalysis. On this p-CuNi@NF catalyst, NiO is able to accelerate the hydrogenation step by promoting the water dissociation to provide protons, ultimately facilitating efficient NRA. p-CuNi@NF exhibits excellent NH selectivity and yield in a wide potential range and reaches a high Faradaic efficiency (FE) of 97.5 % and a yield (Y) of 470 μmol h cm at -0.6 V, both of which largely surpass the Cu/CuO catalyst.