Remarkable improved electro-Fenton efficiency by electric-field-induced catalysis of CeO2

In this study, we designed a novel combined electro-Fenton system for the treatment of wastewater containing biological recalcitrant using electric-field-induced ceria (CeO2) as the synergistic catalysts. It was found that by applying this CeO2 electro-Fenton system, the current efficiency improved from 74.49% to 109.82% within 2.5 min; the removal efficiency for dimethyl phthalate (DMP) increased from 85.5% to 94.9% within 20 min; and the mineralization rate increased from 76.01% to 93.58% after 120 min. The effects of parameters such as the applied potential, electrolyte, and concentration of Fe2+ on the current efficiency were systematically studied. Investigations by LSV, zeta titration, X-ray photoelectron spectroscopy (XPS), X-Ray Diffraction (XRD)and electron spin resonance (ESR)revealed the reasons for achieving a current efficiency of over 100% in the CeO2 electro-Fenton system. A mechanism that involved Bronsted acid sites and the redox cycle of sulfate CeO2 was proposed.