Dependence of Photocatalytic Activity of TiO2-SiO2 Nanopowders

Structural properties and chemical composition change the photocatalytic activity in TiO2-SiO2 nanopowder composite. The SiO2-TiO2 nanostructure is synthesized based on sol-gel method. The nanoparticles are characterized by x-ray fluorescents (XRF), xray diffraction (XRD), tunneling electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), UV-vis. Spectrophotometer and furrier transmission create infrared absorption (FTIR) techniques. The rate constant k for the degradation of methylen blue in its aqueous solution under UV irradiation is determined as a measure of photocatalytic activity. Dependence between photocatalytic activity and SiO2 content in the composite is determined. Rate constant k is found dependent on the content of SiO2 in the composite that calcined at 900 oC. The addition of low composition SiO2 to the TiO2 matrix (lower than 45%) enhances the photocatalytic activity due to thermal stability and increasing in the surface area. The effects of chemical compositions on the surface topography and the crystallization of phases are studied.