Ru Single Atoms Anchored on Multicomponent Metal Oxides for Enhanced Chlorine Evolution and Reactive Oxygen Species Generation

The electrochemical production of sodium hypochlorite (NaClO) and reactive oxygen species (ROS) offers potential for water treatment. Although chlorine evolution reaction (CER) and ROS generation had been widely investigated in acidic media, further exploration was warranted under tap-water conditions. In this study, a ruthenium single-atom-based electrocatalyst (Ru SAs/IrCeO_x/Co₃O₄) was developed, which achieved a Faradaic efficiency (FE) of 98.5% for CER in acidic electrolyte and demonstrated stable operation for 1750 h at 625 mA·cm^-2 during an accelerated durability test. The electrocatalyst generated 1.4 ppm total oxidants within 2 min in simulated tap water, and showed stability for 1630 h in a medium-salinity electrolyte. Theoretical analyses demonstrated that Ru SAs/Co₃O₄ surface lowered the thermodynamic barrier for Cl₂ formation, the moderate chlorine adsorption energy of IrO₂ establishes an electrocatalytic interface for the reaction system, CeO₂ facilitated the spontaneous generation of *O species and promoted O-O coupling, endowing the electrocatalyst with bifunctional activity toward both CER and ROS production under simulated tap water conditions. The electrocatalyst, coupled with a self-designed continuous-flow electrolyzer, achieves 95% pollutant degradation within 30 min. This study provides guidance for reducing the fabrication cost of commercial DSA electrodes and enabling their application in advanced electrochemical oxidation processes.