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

The nitrite electroreduction reaction (NO2ERR) offers a promising pathway for ammonia (NH3) synthesis and the remediation of nitrite pollutants. Copper (Cu)‐based nanomaterials have demonstrated significant potential as NO2ERR 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 NO2ERR (Faradaic efficiency: 95.26%; NH3 yield: 2.54 mg h−1 gcat−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 NO2ERR||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 NH3. Under light irradiation conditions, the electrolysis voltage of the NO2ERR||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 NO2ERR coupled with SEOR.