High-activity and excellent-reusability γ-Fe₂O₃/SiO₂ coating on TC4 titanium alloy by plasma electrolytic oxidation for enhanced photo-Fenton degradation

The immobilized coatings as a kind of promising Fenton-like catalysts with excellent performance and reusability for the efficient degradation of antibiotics and phenol under solar light irradiation is investigated. Herein, the porous γ-Fe₂O₃/SiO₂ immobilized ceramic coating on TC4 titanium alloy as photo-Fenton catalyst was prepared via plasma electrolytic oxidation technology. The as-obtained immobilized coating manifested a remarkable catalytic activity that the removal efficiencies of phenol and various antibiotics could reach more than 92% within 90 min, and presented excellent reusability after six runs in phenol removal. The high activity and excellent reusability of γ-Fe₂O₃ were attributed to the synergistic effect of multiple pathways to jointly produce abundant •OH, and the combination of γ-Fe₂O₃ and SiO₂ in the coating could effectively reduce iron leaching during the heterogeneous photo-Fenton process, respectively. This work provides a novel strategy for the synthesis of high-performance photo-Fenton catalysts to dispose of wastewater in the future.