Photodegradation of volatile organic compounds using zirconium-doped TiO2/SiO2 visible light photocatalysts

Abstract

Visible light responsive zirconium-doped TiO2/SiO2 photocatalysts were prepared via the sol–gel process. The photocatalysts were characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), the Brunauer–Emmett–Teller method (BET), and UV–Vis spectrophotometery. The Zr/TiO2/SiO2 photocatalyst had an anatase TiO2 crystalline structure, a high specific area, small crystal size, and visible light response. The XPS spectra of the Zr/TiO2/SiO2 catalysts indicated that Si and Zr were doped into the TiO2. The photocatalysts were tested in the photodegradation of toluene and xylene. To optimize the reaction, the catalyst surface area, initial toluene and xylene concentrations, and light intensity of UV and visible light were varied. The photocatalytic activity of the Zr/TiO2/SiO2 catalyst was considerably greater than that of commercial TiO2 (Degussa P25) under both UV and visible light irradiation. Light intensity and initial concentration were key factors influencing the photocatalytic degradation rate.