Electrochemical nitrate reduction reaction (NO₃RR) is a promising means for generating the energy carrier ammonia. Herein, we report the synthesis of heterostructure copper-nickel phosphide electrocatalysts via a simple vapor-phase hydrothermal method. The resultant catalysts were evaluated for electrocatalytic nitrate reduction to ammonia (NH₃) in three-type electrochemical reactors. In detail, the regulation mechanism of the heterogeneous Cu₃P−Ni₂P/CP−x for NO₃RR performance was systematically studied through the H-type cell, rotating disk electrode setup, and membrane-electrode-assemblies (MEA) electrolyzer. As a result, the Cu₃P−Ni₂P/CP−0.5 displays the practicability in an MEA system with an anion exchange membrane, affording the largest ammonia yield rate (R_NH3) of 1.9 mmol·h⁻¹·cm⁻², exceeding most of the electrocatalytic nitrate reduction electrocatalysts reported to date. The theoretical calculations and in-situ spectroscopy characterizations uncover that the formed heterointerface in Cu₃P−Ni₂P/CP is beneficial for promoting nitrate adsorption, activation, and conversion to ammonia through the successive hydrodeoxygenation pathway.

电化学硝酸盐还原反应（NO ₃ RR）是产生能量载体氨的一种有前景的方法。在此，我们报告了通过简单的气相水热法合成异质结构铜镍磷化物电催化剂。评估所得催化剂在三种类型的电化学反应器中电催化硝酸盐还原为氨(NH ₃ )。具体来说，通过H型电池、旋转盘电极装置和膜电极组件（MEA）电解槽系统地研究了异质Cu ₃ P−Ni ₂ P/CP− x对NO ₃ RR性能的调节机制。结果表明，Cu ₃ P−Ni ₂ P/CP−0.5在带有阴离子交换膜的MEA系统中显示出实用性，提供了1.9 mmol·h ⁻¹ ·cm ^{−2的最大氨产率（} R _NH3），超过了迄今为止报道的大多数电催化硝酸盐还原电催化剂。理论计算和原位光谱表征表明，Cu ₃ P−Ni ₂ P/CP中形成的异质界面有利于促进硝酸盐吸附、活化，并通过连续的加氢脱氧途径转化为氨。