Carbon sphere-anchored Co-Ce bimetallic oxides with engineered oxygen vacancies enable efficient catalytic ozonation for water purification

Catalytic ozonation can remove persistent organic micropollutants from water, but its efficiency is limited by how effectively catalysts convert ozone into reactive oxidants while remaining stable under aqueous conditions. Here, we report a carbon-sphere-mediated interfacial engineering strategy for Co-Ce bimetallic oxides with tunable oxygen vacancies. By adjusting carbon loading, the catalyst balances oxide accessibility, defect-associated surface oxygen species, and interfacial electronic coupling. The optimized Co 4 Ce 6 O x-δ @CS-1.6 catalyst achieved complete atrazine removal within 9 min and 53.4% total organic carbon reduction within 30 min, with an apparent rate constant of 0.426 min -1 , 10.9 times higher than single ozonation and 9.3 times higher than the parent Co-Ce oxide. Multitechnique characterization showed that the carbon coupling improved oxide dispersion and modulated Co/Ce redox states while maintaining high structural stability at Co active sites after ozonation. This electronic tuning driven by carbon integration shifted ozone activation from a molecular pathway on parent Co 4 Ce 6 O x to a vacancy-assisted dissociative pathway forming surface-bound *O on Co 4 Ce 6 O x-δ @CS-1.6. The resulting system promotes radical-mediated oxidation dominated by •OH and •O 2 - -related pathways, driving atrazine through dealkylation, dechlorination, hydroxylation, and further oxidation with an overall decrease in predicted aquatic toxicity. The catalyst also enables atrazine removal from real pesticide wastewater, removes diverse micropollutants, and improves COD reduction in real water matrices, highlighting oxide-carbon interfacial defect engineering as a promising route for ozone-based water purification under complex aqueous conditions. Download: Download high-res image (504KB) Download: Download full-size image