Interface engineering for bismuth tungstate and lanthanum cobaltate towards promoted sulfamethoxazole photocatalytic oxidation

Diversified photocatalysts with high catalytic activity and durability are urgently needed for antibiotics degradation upon environmental remediation. Herein, we devised a unique catalyst, LB-2 (LaCoO3:Bi2WO6=1:2, mole ratio), which constitute of by ultrathin aurivillius perovskite Bi2WO6 (BWO) nanosheets growing on classical perovskite LaCoO3 (LCO) nanofibers. The novel complex catalyst exhibited outstanding catalytic activity and superior stability for sulfamethoxazole (SMX) degradation. The degradation efficiency of LB-2 for SMX achieved 91.3% and the efficiency still remained at 76% after cycling experiments, indicating the excellent stability of LB-2. Probable synergistic mechanisms between Bi2WO6 and LaCoO3 were investigated by active species capture experiments and electron spin resonance (ESR). In addition, possible products of different routes of SMX degradation were presented based on high performance liquid chromatography-tandem mass spectrometry (HPLC/MS). This investigation proposes the application of composite chalcogenide oxides in the photocatalytic degradation of SMX, and confirmed that the heterojunction interface between chalcogenide oxides is the key to enhance the performance according to the experimental and mechanistic investigation.