Harnessing Surface‐Tuned Ag/Cu Interfaces in Ag/Ag ₂ O/CuO for High‐Efficiency Ammonia Synthesis and Co‐Electricity Generation in Zn–Nitrate Batteries

Abstract This study presents a hierarchical silver/silver oxide/copper oxide (Ag/Ag ₂ O/CuO) composite with high electrocatalytic efficiency for the nitrate (NO ₃ ⁻ ) reduction reaction (NO ₃ RR). The Ag/Ag ₂ O/CuO composite is synthesized using a single‐pot pulsed laser ablation in liquid method. The incorporation of Ag/Ag ₂ O nanoparticles enhances the conductivity of the Ag/Ag ₂ O/CuO composite electrocatalyst, enabling a maximum Faradaic efficiency (FE) of 92.2% for NH ₄ ⁺ production with a yield rate of 6.4 mg·h ⁻¹ ·cm ⁻² during the NO ₃ RR at a reduction potential of −0.3 V versus reversible hydrogen electrode. In‐depth analysis of the NO ₃ RR kinetics using in situ and ex situ spectroscopic techniques reveals surface‐tuning of the metallic Ag/Cu interface on the Ag/Ag ₂ O/CuO composite electrocatalyst during the NO ₃ RR, which plays a vital role in enhancing the NO ₃ RR performance, further supported by density functional theory. Remarkably, a Zn–nitrate battery fabricated using the Ag/Ag ₂ O/CuO composite cathode and a Zn anode demonstrates an open‐circuit voltage of 1.48 V, achieving impressive NO ₃ ⁻ to NH ₄ ⁺ conversion with an FE of 93.5% at a current density of 8 mA·cm ⁻² . This study not only presents a novel methodology for developing a Ag/Ag ₂ O/CuO composite but also provides insights into its superior NO ₃ RR performance in Zn–nitrate batteries for green NH ₃ synthesis and co‐electricity generation.