Oxygen vacancy-regulated RuO2 enables high chlorine evolution selectivity for deep organic mineralization and reuse of chlor-alkali wastewater

Insufficient chlorine evolution reaction (CER) selectivity over the competing oxygen evolution reaction (OER) limits chloride-mediated electro-oxidation for deep mineralization and reuse of Cl − -laden PVC wastewater, particularly under near-neutral and 0.25–1 mol/L Cl⁻ ranges. Here, RuO 2 /Ti 4 O 7 porous anode was prepared to enable excellent CER while limiting OER activities through leveraging the interfacial electronic coupling effect between oxygen vacancy-rich Ti 4 O 7 support and Ru sites. The low Ru loading RuO 2 /Ti 4 O 7 delivered 60–93% Faradaic efficiency and higher active species production than DSA in neutral solutions from wide Cl⁻ range. A flow-through electrochemical reactor using RuO 2 /Ti 4 O 7 was constructed and maintained >88.9% TOC removal in 360 h continuous wastewater treatment with 0.25–1 mol/L Cl − concentration ranges. The high efficiency of Cl-mediated ·OH formation via RuO 2 /Ti 4 O 7 ensured the sustained mineralization pathway, and showing >93.5% TOC removal during 400 h continuous treatment within complex actual wastewater. Effluent treated by this electrochemical system directly meets ion-exchange membrane electrolyser reuse standards (influent TOC <10 mg/L), enabling complete salt water recovery and confirming its huge potential in chlor-alkali industry.