Preparation and performance study of ZnWO₄/TiO₂/MoS₂ ternary composite photocatalyst

The ZnWO₄/TiO₂/MoS₂ (ZTM) ternary composite catalyst was prepared based on the excellent performance binary photocatalyst semiconductor ZnWO₄/TiO₂ composite powder. The application potential of the photocatalyst to decolorization of methylene blue (MB) dyes under sunlight was studied. The composites were characterized by X-ray diffraction technique (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The properties of the composites were tested with BET methods, ultraviolet–visible (UV–Vis) spectrophotometer and photoluminescence (PL) techniques. The experimental results indicate that the ternary catalyst has a nanorod-like morphology, better crystallinity, and large specific surface area. The specific surface area of ZTM-0.5 semiconductor photocatalyst is 2.54 times that of pure ZnWO₄ and 1.83 times that of binary semiconductor photocatalyst. Compared with pure ZnWO₄, the band gap of ZnWO₄ is significantly reduced, and it has excellent photocatalytic properties, and the degradation rate of MB can reach 99%. The composite of MoS₂ also inhibits the composite of photogenerated electron–hole pairs, improves the concentration of photocatalytic intermediates, not only improves the photocatalytic activity, but also improves the stability of the photocatalyst. After three cycles of degradation experiments, the degradation efficiency of ZTM-0.5 photocatalyst remains at 65%. The main radical affecting the photocatalysis through the trapping agent benzoquinone test is the superoxide radicals (·O₂⁻). Graphical abstract: Possible photocatalytic reaction mechanism of ZnWO₄/TiO₂/MoS₂ composite. The ZnWO₄/TiO₂/MoS₂ ternary composite catalyst was prepared based on the excellent performance binary photocatalyst semiconductor ZnWO₄/TiO₂ composite powder. The phase composition, microstructure, and photocatalytic properties of the molybdenum disulfide composites at different mass percentages were investigated.[Figure not available: see fulltext.]