Preparation of titanium dioxide/tungsten disulfide composite photocatalysts with enhanced photocatalytic activity under visible light

Titanium dioxide/tungsten disulfide (TiO 2 /WS 2 ) composite photocatalysts were fabricated via a one-step hydrothermal synthesis process, using TiCl 4 as titanium source and bulk WS 2 as sensitizer. The morphology, structure, specific surface area and optical absorption properties of the composite photocatalysts were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), specific surface area analyzer and ultraviolet-visible diffuse reflection spectrum (UV-vis DRS), respectively. The photocatalytic activity of as-prepared photocatalysts was evaluated by the degradation of methyl orange (MO) under illumination of 500W Xenon lamp. The results indicated that TiO 2 /WS 2 composite photocatalysts possessed excellent photocatalytic activity, and ∼95% of the degradation rate for MO was reached when molar ratio of WS 2 to TiO 2 was 0.004 and the irradiation time was 60 min. Moreover, the carrier trapping experiment and fluorescence spectra showed that ·O − 2 was the key component in the photocatalytic degradation process and O 2 was reduced to be ·O − 2 by the electrons from the conduction band of TiO 2 and WS 2 for the degradation of MO.