Construction and synthesis of S-WO₃/BiInOCl photocatalyst via synergistic ion doping and heterojunction engineering for efficient degradation of MB

The rapid industrialization has exacerbated organic pollutant emissions, while conventional treatment methods suffer from inefficiency and high operational costs. Photocatalysis attracts considerable interest given its efficiency and eco-friendliness. A sulfur-doped WO₃ (denoted as S-WO₃)/BiInOCl composite photocatalyst was constructed via a facile hydrothermal method. The photocatalytic properties of composites were thoroughly explored through the evaluation of their organic dye decomposition. The micromorphology, band structure, and carrier migration mechanism of these composites were analyzed using diversified characterization techniques. The findings reveal Sulfur-doped ability to decrease the bandgap of WO₃, broaden its light absorption spectrum, and significantly increase its photocatalytic efficacy. Adding BiInOCl improves the stacking order in S-WO₃ and facilitates the dissociation of electron-hole pairs originating from the heterojunction. More importantly, S-scheme heterojunction was successfully built at the interface of S-WO₃ and BiInOCl material, which was corroborated by XPS spectra, photo-electrochemistry, radical trapping experiments, and EPR tests. The S-WO₃/BiInOCl composite photocatalyst exhibited a degradation efficiency of 98 % within 24 min, representing a 4.8-fold and 1.9-fold enhancement compared to S-WO₃ and BiInOCl, respectively. Moreover, after three experimental cycles, the hybrid photocatalyst retains significant degradation efficacy, demonstrating superior photochemical robustness and recyclable properties.