Synergistically tuning intermediate adsorption and promoting water dissociation to facilitate electrocatalytic nitrate reduction to ammonia over nanoporous Ru-doped Cu catalyst

Electrochemical nitrate reduction reaction (NO3RR) for ammonia generation has garnered attention as an emerging alternative to the energy intensive Haber-Bosch process for sustainable ammonia synthesis and wastewater treatment. However, current NO3RR still suffers from low ammonia yield and poor selectivity due to the lack of effective electrocatalysts. Here, the bimodal nanoporous Ru-doped Cu catalyst prepared by the dealloying method is reported as an electrocatalyst for NO3RR, which exhibits an ultrahigh ammonia yield rate of 29.63 ± 0.74 mg h−1 mgcat.−1with 97.3% ± 2.5% Faradaic efficiency at −0.2 V versus reverse hydrogen electrode, outperforming most of the reported catalysts under similar conditions. Density functional theory calculations reveal that doping Ru into Cu can optimize the adsorption energies of intermediates and lower the energy barrier of the rate-determining step of NO3RR. Moreover, Ru atom can promote H2O adsorption/dissociation to supply reactive hydrogen species for N-containing intermediates hydrogenating to ammonia. This work provides a new avenue for the rational design of high-performance catalysts for NO3RR and other important applications.