Photocatalysis and characterization of the gel-derived TiO2 and P-TiO2 transparent thin films

The gel-derived TiO2 and P-TiO2 transparent films coated on fused-SiO2 substrates were prepared using a spin-coating technique. Effects of phosphorus dopants and calcination temperature on crystal structure, crystallite size, microstructure, light transmittance and photocatalytic activity of the films were investigated. By introducing P atoms to Ti-O framework, the growth of anatase crystallites was hindered and the crystal structure of anatase-TiO2 could withstand temperature up to 900 degrees C. The photocatalytic activities of the prepared films were characterized using the characteristic time constant (tau) for the photocatalytic reaction. The titania film with a smaller T value possesses a higher photocatalytic ability. After exposing to 365-nm UV light for 12 h, the P-TiO2 films calcined between 600 degrees C and 900 degrees C can photocatalytically decomposed >= 84 mol% of the methylene blue in water with corresponding tau <= 7.1 h, which were better than the pure TiO2 films prepared at the same calcination temperature. (C) 2011 Elsevier B.V. All rights reserved.