Synergistic effects at the interface of core–shell Cu3P@CoO heterojunctions for enhanced nitrate reduction to ammonia

Abstract

The electrochemical reduction of nitrate (NO₃RR) represents a sustainable strategy for generating valuable ammonia while eliminating nitrate contaminants from water. Nevertheless, developing highly selective and active electrocatalysts remains crucial for optimizing ammonia yield. Herein, we report the design of a core–shell Cu₃P@CoO heterostructure serving as an efficient electrocatalyst for ambient nitrate-to-ammonia conversion. Electrochemical tests conducted in an electrolyte containing 0.1 M NaOH and 0.1 M NaNO₃ demonstrate that this material delivers a large NH₃ production rate of 9201 µg h⁻¹ cm⁻² and a high faradaic efficiency of 92% while maintaining excellent stability. Density functional theory (DFT) reveals that the superior NO₃RR performance of Cu₃P@CoO stems from the synergistic cascade interaction between the core–shell Cu₃P and CoO. Accordingly, this study offers a blueprint for engineering core–shell-based multi-site cascade catalysts to optimize nitrate reduction efficiency.