In this study, it was indicated that hydrothermal post-alkali-treated plasma electrolytic oxidation (PEO) coating using NaOH as the reducing agent is an effective catalyst for tetracycline (TC) visible light photodegradation. The post-alkali treatment can not only change the coating surface morphology but also introduce oxygen vacancies (OVs) into them, resulting in extending the light response to visible light and inhibiting the recombination of photogenerated electron-hole (e−-h+) pairs.
