Effect of substrates on the photocatalytic activity of nanometer TiO2 thin films

Abstract Transparent anatase TiO 2 nanometer thin films with photocatalytic activity were prepared via the sol-gel method on soda-lime glass, fused quartz, and soda-lime glass precoated with a SiO 2 layer. The resulting thin films were characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The photocatalytic activity of the various TiO 2 films was evaluated by the photocatalytic decolorization of aqueous methyl orange. The diffusion of sodium and calcium ions from the soda-lime glass into the nascent TiO 2 films was found to be detrimental to the photocatalytic activity of the resulting TiO 2 films. Sodium and calcium diffusion into nascent TiO 2 films was effectively retarded by a 0.3 μm SiO 2 interfacial layer formed on the soda-lime glass.