NiO‐Incorporated Cu/Cu2O Nanowires for Highly Efficient Electrochemical Nitrate Reduction to Ammonia

Abstract Electrochemical nitrate reduction to ammonia (NRA) is a promising sustainable way to synthesize ammonia (NH 3 ) from nitrate (NO 3 − ) contaminants. Cu‐based electrocatalysts are frequently utilized for NRA due to their strong NO 3 − 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 x , typically NO 2 − ) to target NH 3 . Herein, NiO‐incorporated Cu/Cu 2 O nanowires grown on nickel foam (p‐CuNi@NF, p refers to plasma treatment) were synthesized via hydrothermal growth and subsequent O 2 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 3 selectivity and yield in a wide potential range and reaches a high Faradaic efficiency (FE NH3 ) of 97.5 % and a yield (Y NH3 ) of 470 μmol h −1 cm −2 at −0.6 V, both of which largely surpass the Cu/Cu 2 O catalyst.