The synergistic effect of oxygen vacancies and acidic properties of SO42-/ CexZr1_xO2 on enhancing the Electro-Fenton performance in antibiotics wastewater treatment

Recently, bi-functional catalysts have emerged as an effective approach for enhancing the performance of electro-Fenton in degrading antibiotics by simultaneously improving H2O2 generation and Fe circulation. Herein, we prepared a SO42-modified CexZr1-xO2 bi-functional catalyst to construct an efficient e-Fenton system for degrading norfloxacin. Results display that the fabricated catalyst exhibited superior performance in degrading norfloxacin owing to durative generated center dot OH, which was proved to be the dominant active species. The H2O2 generation capacity of that catalyst was twice higher than the pure e-Fenton and its faradaic efficiency even came up to 75%. The amount of soluble total Fe and Fe2+ ions of that catalyst were both increased twofold compared to the blank system, declaring the acceleration of Fe recycling process. Characterizations and density function theory calculations proposed a synergistic mechanism that attributed the simultaneously improvement in H2O2 generation and Fe2+ circulation to the multiple regulated interface properties, the promoted 2e-ORR activity caused by enriched oxygen vacancies at Ce sites, and the accelerated electrons transfer owing to the strengthened acidic sites for the coordination between Zr sites and S species. Furthermore, that catalyst is also proved to be feasible, well-recycled and practical for application in wastewater purification.