Proton-electron synergistic transport in nickel-Iron layered double hydroxide decorated Cu/Cu₂O heterostructure for...

Electrochemical nitrate reduction reaction (NO₃RR) provides a sustainable approach for ammonia synthesis and environmental remediation; however, the multi-step proton-coupled electron transfer processe poses significant challenges for achieving high efficiency and selectivity. Herein, we engineered a self-supporting NiFe-LDH@Cu/Cu₂O (LDH: layered double hydroxides) heterostructure via facile hydrothermal and electrochemical deposition methods. The optimized electrode delivers exceptional NH₃ synthesis performance (1.06 ± 0.058 mmol h^-1 cm^-2 and a Faraday efficiency of 97.6 ± 1.88% at -0.4 V vs. RHE) and an excellent long-term stability. The experimental and theoretical calculation results reveal that NiFe-LDH accelerates water dissociation to yield abundant active hydrogen (*H) species, relieving the *H shortage during the reaction. The Schottky interface of Cu/Cu₂O further optimizes interfacial electronic configuration, facilitates electron transport, and strengthens the adsorption of NO₃^- and reaction intermediates. The tightly coupled NiFe-LDH@Cu/Cu₂O heterointerface realizes a highly efficient proton-electron synergistic relay. This distinctive effect drives the coordinated transport of electrons and protons, maximizes the utilization of active hydrogen, and expedites the deep hydrogenation of NO₂^- intermediates. This work provides a rational design strategy for enhancing NO₃RR performance toward waste nitrate treatment and green ammonia synthesis via proton-electron coupled transfer engineering.