Fabrication of TiO₂/MoS₂ Composite Photocatalyst and Its Photocatalytic Mechanism for Degradation of Methyl Orange under Visible Light

Abstract

Abstract A novel TiO 2 /MoS 2 composite photocatalyst with high visible‐light activity was prepared via a one‐step hydrothermal process using titaniumtetrachloride (TiCl 4 ) as a titanium resource and bulk MoS 2 as a direct photosensitizer. The photocatalytic degradation of methyl orange (MO) in aqueous suspension was employed to evaluate the visible light activity of the as‐prepared composite photocatalyst with a xenon lamp as simulated solar irradiation. The chemical composition, optical properties, morphology, structure, and thermal stability of the composite photocatalysts were characterized using XPS, UV‐vis, FS, SEM, XRD, and TGA. The as‐prepared photocatalysts exhibited enhanced photocatalytic activity from the experiment on the degradation of methyl orange, compared to the performance of commercial titania (Degussa P25). The degradation rate of MO can reach over 90 % in 10 min when the molar ratio of molybdenum disulfide (MoS 2 ) to titanium dioxide (TiO 2 ) is 0.8:50 and the mass concentration of the TiO 2 /MoS 2 composite photocatalyst is 400 mg/L. In this research, a new fabrication mode of TiO 2 /MoS 2 /TiO 2 was applied for fabricating new hybridized structures of nano‐TiO 2 /MoS 2 by using bulk MoS 2 as a direct photosensitizer, which changed the energy levels of the conduction band of MoS 2 and strongly promoted interparticle electron transfer. In addition, this hybridization structure was believed to have a synergistic effect in the process of photocatalytic oxidation owing to increasing the degree of charge carrier separation, which effectively reduced recombination and improved the photocatalytic activity of the TiO 2 /MoS 2 composite photocatalyst.