A novel S-type CsxWO3/BiOI heterojunction photocatalyst constructed in graphene aerogel with high degradation efficiency for enrofloxacin: Degradation mechanism and DFT calculation

The construction of semiconductor heterojunction photocatalyst is an effective way to improve the photo-catalytic performance. In this study, a novel S-type heterojunction CsxWO3/BiOI photocatalyst, with both pho-tothermal effect and good photocatalytic activity, was constructed in graphene aerogel. The as-prepared composite aerogel showed high adsorption/photocatalytic activity and cycling stability for removal of enro-floxacin. Especially, the aerogel sample 1.0CIGA with CsxWO3:BiOI molar ratio 1.0 showed a high removal ef-ficiency of enrofloxacin with attaining to nearly 100% within 60 min. Moreover, the photothermal conversion effect of CsxWO3 can further promote the photocatalytic degradation reaction efficiency. The degradation in-termediate products and possible degradation pathways of enrofloxacin were analyzed and explored. In addition, the energy band structure and charge transfer mechanism of CsxWO3/BiOI heterojunction were studied by density functional theory (DFT) and other test methods. This work is of great significance for developing efficient photocatalytic materials and the as-prepared CsxWO3/BiOI@graphene composite aerogel with high adsorption/ photothermal catalysis will have promising applications in the field of environmental purification.