• • Achieves an ammonia yield of 0.382 mmol h−1 cm−2 and Faraday efficiency of 80.4% at −0.3 V vs. RHE, surpassing typical Cu2O-based catalysts that suffer from low selectivity and rapid deactivation; this performance meets industrial ammonia production demands for energy-efficient nitrate remediation.
• • The NiCo-LDH/Cu2O heterojunction prevents nitrite (NO2−) accumulation, a critical failure mode in Cu2O catalysts, by stabilizing reaction intermediates through interfacial electronic coupling; this ensures continuous operation without toxic byproduct release, addressing environmental compliance in wastewater treatment.
• • Adjusting the Ni/Co ratio modulates proton behavior: Co facilitates efficient H2O dissociation for H* supply, while Ni regulates H* consumption toward NO3RR rather than HER; this dual-site regulation suppresses the competing hydrogen evolution reaction, enhancing selectivity and reducing energy waste.
• • The heterojunction overcomes the poor conductivity of LDH and low electron transfer rates, as evidenced by reduced charge transfer resistance (Rct) in Co-free catalysts; this improvement enables faster kinetics and higher current densities, critical for scalable electrochemical reactors.