The electrochemical reduction of nitrate to ammonia (ENRA) provides an efficient approach to remove nitrate pollution and achieve ammonia production simultaneously. Herein, inspired by bio-enzyme in denitrifying bacteria, a carbon-coated nickel phosphide (NiPC) nanosheet derived from metal-organic frameworks (MOFs) is proposed as an efficient catalyst for ENRA. Through electron engineering, controllable Ni^δ+ in nickel phosphide is achieved by regulating the degree of phosphating, which enhances its activity for the hydrogenation of nitrate. As the result, Ni^δ+ becomes one of dominating factors determining the efficiency of the ENRA reaction in nickel phosphide. The optimal NiPC catalyst exhibits impressive property toward ENRA: NH₄⁺ Faraday efficiency of 96.68%, NH₄⁺ selectivity of 99.04%, and nitrate conversion rate of 90.43% under low nitrate concentration (200 mgL⁻¹). This work opens a new avenue for the design of next-generation catalysts through electron engineering for ENRA.

硝酸盐电化学还原为氨（ENRA）提供了一种去除硝酸盐污染并同时实现氨生产的有效方法。在此，受反硝化细菌中生物酶的启发，提出一种源自金属有机框架（MOF）的碳包覆磷化镍（NiPC）纳米片作为 ENRA 的有效催化剂。通过电子工程，通过调节磷化程度实现了磷化镍中^Niδ+的可控，增强了其对硝酸盐加氢的活性。因此，Niδ ⁺成为决定磷化镍ENRA反应效率的主导因素之一。优化的NiPC催化剂对ENRA表现出令人印象深刻的性能：在低硝酸盐浓度（200 mgL ^{-1 ）下，NH} ₄ ⁺法拉第效率为96.68%，NH ₄ ⁺选择性为99.04%，硝酸盐转化率为90.43% 。这项工作为 ENRA 通过电子工程设计下一代催化剂开辟了一条新途径。