Amorphous Copper‐Coated Crystalline Cobalt Nanowire for Electrocatalytic Nitrate Reduction to Ammonia in Neutral Medium
Jianlu Wei, Yujing Liu, Ze Wu, Linhu Han, Aomeng Deng, Qiu‐Yue Li, Chenmeng Jiang, Jingjing Liu, Lang Gan, Yiqiong Zhang, Shuangyin Wang
Abstract
Abstract The direct electrocatalytic reduction of nitrate (NO 3 − ) to ammonia (NH 3 ) presents an energy‐efficient and promising strategy for wastewater treatment and the nitrogen cycle. However, under neutral conditions, the electrocatalytic process faces the challenge of insufficient active hydrogen (*H) supply and difficulty in hydrogenation of nitrogen‐containing intermediates. Herein, in this work, an amorphous copper‐coated crystalline cobalt nanowire (c‐Co@a‐Cu) catalyst is successfully fabricated for nitrate electroreduction, which achieves a high NH 3 yield rate (4.63 mg h −1 cm −2 ) and Faradaic efficiency (99.6%) at −0.6 V versus RHE in a neutral medium, outperforming its crystalline counterpart. The high‐resolution HAADF‐STEM and theoretical calculations indicate that amorphous Cu species coating on the Co nanowire surface synergistically enhance NO₃⁻ adsorption via Co‐Cu interactions. The c‐Co@a‐Cu catalyst lowers the energy barrier for *NO 3 H formation from *NO 3 , suppresses the hydrogen evolution reaction (HER), and provides abundant reactive hydrogen (*H) to facilitate hydrogenation of nitrogenous intermediates, ultimately accelerating nitrate‐to‐ammonia conversion. Furthermore, a peak power density up to 5.90 mW cm −2 and an NH 3 yield of 277.20 µg h −1 cm −2 have been realized in a homemade Zn‐NO 3 ‐ battery, achieving the integration of power output, nitrate treatment, and green ammonia production.