Interface coupling induced electronic effect of NiCo-LDH/Cu2O heterojunction catalysts towards efficient electrochemical nitrate reduction to ammonia
Electrocatalytic nitrate reduction to ammonia (NO3RR) offers a sustainable alternative to the Haber-Bosch process but is limited by insufficient atomic hydrogen (H*) supply and sluggish hydrogenation of oxynitride intermediates. This study constructs a NiCo-LDH/Cu2O heterojunction catalyst via a facile hydrothermal method, leveraging the strong nitrate adsorption of Cu2O and interfacial coupling with NiCo layered double hydroxides. By tuning the Ni/Co ratio, proton absorption behavior is modulated, achieving an ammonia yield of 0.382 mmol h−1 cm−2 and a Faraday efficiency of 80.4% at −0.3 V vs. RHE. Experimental results demonstrate that interfacial coupling induces optimal electronic effects, enhancing adsorption and activation of reaction intermediates, optimizing the reaction pathway, and suppressing the competing hydrogen evolution reaction. The NiCo-LDH/Cu2O system prevents nitrite accumulation and addresses the poor conductivity of LDH and low electron transfer rates. This work provides a feasible strategy for designing efficient, cost-effective NO3RR catalysts for sustainable ammonia synthesis.