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.