Oxygen vacancy-rich Bi12O17Cl12/BiOBr S-scheme heterojunction for enhanced photocatalytic degradation ciprofloxacin: Performance, mechanism and toxicity assessment

Oxygen vacancy-rich Bi 12 O 17 Cl 12 /BiOBr S-scheme heterojunction was successfully constructed through a solvothermal and ethylene glycol-assisted coprecipitation method. Benefited the construction of S-scheme heterojunction structure and the introduction of oxygen vacancy, the separation efficiency of photo-induced carriers is promoted. Under the optimized conditions (catalyst dosage 0.2 g/L, CIP concentration 10 mg/L), the degradation efficiency of CIP achieved 92.64% within 60 min. The corresponding reaction rate constant is 0.03814 min −1 , which is 3.57, 2.82 times than single BiOBr (0.01068 min −1 ) and Bi 12 O 17 Cl 12 -Ov (0.01354 min −1 ). Moreover, h + and O 2 − are the main active species for the degradation of CIP based on active species trapping experiment and EPR spectrum. The degradation pathways were proposed by Density Functional Theory (DFT) calculation and LC-MS analysis. Combining the T.E.S.T. soft stimulate and bean sprout growth experiment proved that the degraded solution has no obvious toxicity. More importantly, Bi 12 O 17 Cl 12 /BiOBr-1 also has a satisfied degradation efficiency for other pollutions. This work provides a feasible strategy to design oxygen vacancy-rich S-scheme heterojunction photocatalysts for wastewater treatment.