Structural and photocatalytic properties of TiO2/SiOx/TiOx multi-layer prepared by electron-beam evaporation method

TiO2/SiOx/TiOx multi-layers on quartz glass were prepared by electron-beam evaporation method and their structural and photocatalytic properties were investigated. The photocatalytic activity of the TiO2/SiOx/TiOx multi-layer was evaluated by the photodecomposition of methylene blue in aqueous solution. As the thickness of the SiOx inter-layer increased, the surface roughness of the TiO2/SiOx/TiOx multi-layer increased but the anatase crystallite size decreased. The TiO2/SiOx(80 nm)/TiOx multi-layer exhibited excellent photocatalytic activity resulting from higher surface roughness and more trap levels in the SiOx(80 nm) inter-layer.