Photocatalytic in situ H₂O₂ production and activation for enhanced ciprofloxacin degradation over CeO₂-Co₃O₄/g-C₃N₄: key role of CeO₂

The abused ciprofloxacin antibiotics have caused significant environmental damage. Although oxidative degradation of ciprofloxacin exhibits promising efficacy, it often entails excessive energy consumption. Hence, it is necessary to explore an effective and ecologically sustainable degradation strategy. Herein, we demonstrated that g-C₃N₄ decorated with the coordinated CeO₂ and Co₃O₄ (CeO₂-Co₃O₄/CN) exhibited effective ciprofloxacin photodegradation via in situ H₂O₂ production and activation mechanism. Results indicate that the introduced CeO₂ enhances the transference of photogenerated electrons to O₂ by adjusting the oxygen vacancy of photocatalyst, thereby increasing the generation of superoxide radicals, which in turn generate H₂O₂, resulting in a 22.4-fold increase in H₂O₂ generation over g-C₃N₄. Moreover, the in situ H₂O₂ generation facilitated by CeO₂ is confirmed to be essential for ciprofloxacin degradation via CeO₂-Co₃O₄/CN, as it provides enough oxidant for Co₃O₄ to activate into hydroxyl radicals for the pollutants degradation. Ultimately, CeO₂-Co₃O₄/CN achieves a ciprofloxacin degradation ratio of 97.7% within 80 min. This study introduces a novel approach that combines H₂O₂ generation and activation, offering an innovative perspective for achieving clean and efficient purification of antibiotic-contaminated water.