Single Ga-Atom Stabilized Cu⁺-Cu⁰ Interfacial Sites for Efficient Air Plasma-Derived Ammonia Electrosynthesis

Electrocatalytic NO_x reduction to ammonia (NO_xRR) offers a sustainable route for decentralized NH₃ synthesis, however, its practical implementation is impeded by sluggish hydrogenation kinetics and the instability of active species. Herein, we develop a Ga single-atom decorated CuO_x/Cu (Ga_SA-CuO_x/Cu) catalyst featuring a strongly coupled Ga-O-Cu coordination structure. The introduction of highly electrophilic Ga³⁺ modulates the electronic structure of Cu via p-d interactions, downshifting the Cu d-band center to weaken excessive intermediate binding, while stabilizing Cu⁺ species to form highly active Cu⁺-Cu⁰ interfacial sites. Meanwhile, Ga sites promote active hydrogen supply and accelerate hydrogenation kinetics on adjacent Cu centers. Benefiting from these synergistic effects, the optimized Ga_SA-CuO_x/Cu achieves a remarkable NH₃ Faradaic efficiency (FE) of 96.21% at -0.4 V versus RHE and high durability at -0.5 A cm^-2. Moreover, a Zn-NO₂ ^-/ethanol battery delivers a peak power density of 17.47 mW cm^-2 with improved charging efficiency, while a plasma-assisted hybrid electrolyzer achieves >95% FEs for both NH₃ and formate at -400 mA cm^-2 and operates stably for 200 h at 0.5 A cm^-2, demonstrating its strong applicability in integrated energy-chemical conversion systems.