Electroreduction of Nitrate to Ammonia on Palladium-Cobalt-Oxygen Nanowire Arrays

Developing high-efficiency electrocatalysts for the selective reduction of nitrate to valuable ammonia is of great significance. Herein, Pd-PdO-modified Co₃O₄ nanowire arrays on nickel foam (PdCoO/NF) are fabricated by a facile cation-exchange reaction. Pd and PdO can facilitate the generation of adsorbed hydrogen, and abundant oxygen vacancies can promote nitrate activation. Therefore, the PdCoO/NF exhibits a superior nitrate conversion rate (89.3%), Faradaic efficiency (88.6%), and ammonium selectivity (95.3%) at -1.3 V versus a saturated calomel electrode. The source of the produced ammonia is confirmed by ¹⁵N isotope labeling experiments and ¹H magnetic resonance. This presented synthetic method provides a powerful strategy for the preparation of nanowire arrays with controllable compositions for selective nitrate electroreduction to ammonia.