d–p orbital hybridization enables efficient chlorine evolution of Ru single atoms in neutral and acidic media

Abstract The chlorine evolution reaction (CER) is essential to the chlor‐alkali industry and water treatment, while most studies focus on high‐chloride acidic systems, with limited research on its performance and mechanisms in neutral tap water (low Cl − with Ca 2+ /Mg 2+ ). This study developed a Ru single‐atom supported on NiSbSnO 2 (Ru/NATO) electrocatalyst and systematically evaluated the CER performance under both acidic and simulated tap water conditions. The Ru/NATO‐1 exhibited a Faradaic efficiency of 97.3% for CER under acidic conditions, a 1.9‐fold improvement compared with NATO. The Ru/NATO‐1 also maintained high activity, with chlorine selectivity increasing significantly from 56% to 90.1% in simulated neutral tap water. Combined experimental and theoretical analyses demonstrated that the d–p orbital hybridization between Ru and Sn atoms in Ru/NATO promoted interfacial electron transfer while modulating the adsorption sites of chlorine‐containing intermediates. These results highlight an effective approach for electrochemical chlorine generation in tap water.