Photocatalytic in situ H 2 O 2 production and activation for enhanced ciprofloxacin degradation over CeO 2 ‐Co 3 O 4 /g‐C 3 N 4 : key role of CeO 2

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‐C 3 N 4 decorated with the coordinated CeO 2 and Co 3 O 4 (CeO 2 ‐Co 3 O 4 /CN) exhibited effective ciprofloxacin photodegradation via in situ H 2 O 2 production and activation mechanism. Results indicate that the introduced CeO 2 enhances the transference of photogenerated electrons to O 2 by adjusting the oxygen vacancy of photocatalyst, thereby increasing the generation of superoxide radicals, which in turn generate H 2 O 2 , resulting in a 22.4‐fold increase in H 2 O 2 generation over g‐C 3 N 4 . Moreover, the in situ H 2 O 2 generation facilitated by CeO 2 is confirmed to be essential for ciprofloxacin degradation via CeO 2 ‐Co 3 O 4 /CN, as it provides enough oxidant for Co 3 O 4 to activate into hydroxyl radicals for the pollutants degradation. Ultimately, CeO 2 ‐Co 3 O 4 /CN achieves a ciprofloxacin degradation ratio of 97.7% within 80 min. This study introduces a novel approach that combines H 2 O 2 generation and activation, offering an innovative perspective for achieving clean and efficient purification of antibiotic‐contaminated water.