Synthesis of a novel hydrophobic CeO2–BiOCl/CF composite cathode for efficient heterogeneous electro-Fenton degradation of tetracycline

Abstract

Bifunctional electrodes have attracted significant research interest in the field of electro-Fenton (EF) processes for the efficient treatment of antibiotic-contaminated wastewater. In this study, carbon felt (CF) was selected as the matrix material because of its excellent electrochemical properties, high porosity, and large specific surface area. BiOCl and CeO₂ were in situ synthesized on the CF electrode using a hydrothermal method, followed by the application of a hydrophobic polytetrafluoroethylene (PTFE) coating on the CF surface. The resulting composite electrode was employed in the EF process for in situ electro-generation and activation of hydrogen peroxide (H₂O₂), facilitating the efficient degradation of tetracycline (TC). Free-radical quenching experiments revealed that hydroxyl radical and superoxide anion radical were the predominant reactive species in the EF process, with hydroxyl radicals playing a major role in the degradation of TC. The electrode exhibited excellent stability over consecutive runs. Furthermore, a plausible mechanism for the production and activation of H₂O₂, as well as the degradation of TC, was proposed. This study provides a new strategy for the construction of efficient and stable bifunctional cathodes for the advanced treatment of antibiotic-contaminated wastewater.