Wide pH range electrocatalytic nitrate reduction to ammonia over high-performance hollow Cu3P nanocubes

The electrocatalytic nitrate reduction reaction (NO 3 RR) to ammonia (NH 3 ) presents a sustainable pathway for wastewater treatment and green NH 3 synthesis. However, developing catalysts that simultaneously achieve high activity, selectivity, and stability over a wide pH range remains a challenge due to the inadequate supply of active hydrogen (*H). Herein, an efficient Cu 3 P hollow nanocubes (Cu 3 P-HNCs) electrocatalyst has been successfully designed for high-performance NO 3 RR over a wide pH range. The as-prepared Cu 3 P-HNCs exhibit excellent performance for NO 3 RR, achieving NH 3 yield rates of 19.77, 26.04 and 12.39 mg h −1 mg cat −1 in neutral, alkaline and acidic electrolytes, respectively. The experimental results and theoretical calculations prove that the hollow cubic architecture endows the Cu 3 P-HNCs with a high specific surface area and multiple catalytic active sites, while phosphoration induces a favorable downshift in the d-band center. This electronic optimization weakens intermediate adsorption and effectively reduces the energy barrier of the key reaction step, ultimately leading to the distinct NO 3 RR performance. This study elucidates a synergistic design strategy and offers insights into designing efficient and robust electrocatalysts for NO 3 RR across a broad pH range.