ABSTRACT Electrocatalytic nitrate reduction reaction (NO 3 RR) offers a sustainable pathway for ammonia production, yet it remains challenging to achieve high activity and high selectivity within a single catalytic system. Herein, we construct a series of MOF‐derived Cu x Co y ‐based catalysts, among which Cu 1 Co 5 ‐based catalysts exhibit outstanding NO 3 RR performance: it delivers a Faradaic efficiency for NH 3 of 97.53% at ‐1.0 V (vs RHE) and an NH 3 yield rate of 22.3 mg · h −1 · mg cat −1 at − 1.1 V (vs RHE), while producing negligible NO 2 − by‐products. By systematically tuning the metal combinations (Cu/Co/Ni), Cu precursors, and Co‐MOF ligands, we established a clear structure‐activity relationship for NO 3 RR. Cu 1 Co 5 ‐based catalysts are a tandem catalyst; Cu─N x sites derived from copper phthalocyanine (CuPc) are indispensable for the initial activation of NO 3 − and the suppression of NO 2 − accumulation, whereas Co‐based sites are markedly superior to Ni in driving the multi‐electron deep hydrogenation of NO x intermediates to NH 3 . This study elucidates the cooperative roles of metal coupling, precursor chemistry, and ligand microenvironment in Co─Cu─N─C architectures, and provides a general structural design strategy for the rational development of next‐generation, high‐efficiency tandem electrocatalysts for nitrate‐to‐ammonia conversion.
Qin et al. (2026) studied this question.