S-scheme CuInS2/WO3 hybrid heterostructures as catalysts for visible-light-driven photo-Fenton degradation of tetracycline hydrochloride

Fabricating highly efficient catalysts for the degradation of persistent antibiotics is challenging. Herein, a series of CuInS2/WO3 hybrid heterostructures with different WO3:CuInS2 weight ratios were fabricated via the in situ growth of CuInS2 nanosheets onto WO3 nanoplates surfaces using a solvothermal reaction. The as-fabricated CuInS2/WO3 hybrid heterostructures were used as S-scheme photocatalysts to remove tetracycline hydrochloride (TCH) from water sources via an efficient photo -Fenton reaction. The phase structures and morphology of the as-fabricated CuInS2/WO3 hybrid heterostructures were systematically characterised using X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The experiments performed to evaluate the structure-activity relationship for the CuInS2/WO3 hybrid heterostructures demonstrated that an S-scheme mechanism was critical for the highly efficient photo-Fenton degradation of TCH. Moreover, the S-scheme mechanism of the CuInS2/WO3 hybrid heterostructures was confirmed using active species trapping and electron paramagnetic resonance measurements. We believe that our study provides useful insights for the fabrication of highly efficient photo-Fenton catalysts.