Defect‐Rich AuCu/CuS Nanowires Heterojunction for Light‐Enhanced Sulfur Ion Electrooxidation Coupled Nitrite Electroreduction

Abstract The nitrite electroreduction reaction (NO 2 ERR) offers a promising pathway for ammonia (NH 3 ) synthesis and the remediation of nitrite pollutants. Copper (Cu)‐based nanomaterials have demonstrated significant potential as NO 2 ERR catalysts, but their catalytic activity and durability are hindered by limitations in the hydrogenation process. In this work, alloying and post‐sulfurization strategies are employed to synthesize AuCu/CuS nanowires (NWs), which feature abundant amorphous active sites and distinct electronic structures. AuCu/CuS NWs exhibit high electroactivity for both NO 2 ERR (Faradaic efficiency: 95.26%; NH 3 yield: 2.54 mg h −1 g cat −1 ) and sulfur ion electrooxidation reaction (SEOR, oxidation potential: −0.05 V at 10 mA cm −2 ). In situ characterization and theoretical calculations explain that amorphous CuS can modify the electronic property of AuCu alloy, thereby optimizing the adsorption of active hydrogen and nitrogen‐containing intermediates. Using AuCu/CuS NWs as a bifunctional electrocatalyst, the assembled NO 2 ERR||SEOR two‐electrode system only requires the electrolysis voltage of 0.77 V to obtain the current density of 10 mA cm −2 , accompanied by the co‐production of sulfur and NH 3 . Under light irradiation conditions, the electrolysis voltage of the NO 2 ERR||SEOR two‐electrode system is further reduced under light irradiation conditions. This study offers a novel approach for the co‐generation of value‐added products through NO 2 ERR coupled with SEOR.