Visible light photocatalytic degradation of organic dyes using W‐modified TiO2/SiO2 catalyst

Abstract In the present study, the synthesis of W‐modified TiO 2 /SiO 2 composite and its catalytic activity in the visible light region is demonstrated. The W‐modified TiO 2 /SiO 2 composite was obtained from the hydrolysis of a mixture containing titanium (IV) oxysulfate, ammonium metatungstate, and SiO 2 powder in an alkaline medium. The obtained materials were characterized by using X‐ray diffraction (XRD), Fourier transformation‐infrared spectroscopy (FT‐IR), high‐resolution transmission electron microscopy (HRTEM), energy dispersive X‐ray elemental mapping observation, nitrogen adsorption/desorption isotherms, photoluminescence spectra (PL), and ultraviolet visible diffusive reflectance spectroscopy (UV‐Vis DRS). In this material, W‐modified TiO 2 nanoparticles of about 3‐5 nm were highly dispersed on the silica network. Both W‐modified TiO 2 and W‐modified TiO 2 decorated on the SiO 2 substrate significantly promoted the visible light absorption of the material. The photocatalytic activity of the prepared catalyst was assessed through the photodegradation of Methylene blue, Rhodamine‐B, Methyl orange, and Congo red dyes under visible light illumination. It was found that the kinetic and equilibrium data of the photocatalytic process fitted the modified Langmuir‐Hinshelwood model well. Recyclable studies have shown that the catalyst still retained its original activity after the third cycle.