Interfacial Engineering in Cu/Co ₄ N Heterostructure toward Ammonia Production from Nitrate Reduction

Electrocatalytic nitrate reduction reaction (NO3RR) offers a bright pathway for ammonia (NH3) production and protection of the environment. Most NO3RR catalysts still suffer from insufficient surface active hydrogen (Hads). In the research, a Cu/Co4N heterostructure is constructed in which the Cu acts as the adsorption for NO3– while the Co4N enhances the water dissociation to supply Hads for the consecutive NO2–-to-NH3 pathway. Due to the synergistic effect, the Cu/Co4N heterostructure exhibits excellent performance for NO3RR in neutral electrolyte. At a potential of −0.6 V vs RHE (reversible hydrogen electrode), the Cu/Co4N heterostructure attained a Faradaic efficiency (FE) of 93% with an NH3 production of 27.64 mg h–1 cm–2. Benefiting from its outstanding NO3RR activity, a Zn-NO3– battery employing the Cu/Co4N heterostructure as the cathode achieved a maximum power density of 10.1 mW cm–2. The study supplies valuable opinions in the tandem catalysis of heterostructure catalysts and offers an aspect for devising high-performance NO3RR catalysts, aiming to achieve effectual selectivity, sustainable NH3 yield, and environmental contamination control.