The synergistic effect of oxygen vacancies and acidic properties of SO42−/CexZr1−xO2 on enhancing the Electro-Fenton performance in antibiotics wastewater treatment

Abstract

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 ⋅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.