Harnessing Surface‐Tuned Ag/Cu Interfaces in Ag/Ag <sub>2</sub> O/CuO for High‐Efficiency Ammonia Synthesis and Co‐Electricity Generation in Zn–Nitrate Batteries
Wordu Go, Raja Arumugam Senthil, Jayesh Cherusseri, Anuj Kumar, Cheol Joo Moon, Wanwisa Limphirat, Mohd Ubaidullah, Myong Yong Choi
Abstract
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.