Alternate coating and porosity as dependent factors for the photocatalytic activity of sol-gel derived TiO2 films

Surfactant-assisted anatase mesoporous TiO2 transparent films, along with P25 translucent films were successfully synthesized and deposited by dip-coating technique. Prepared films were characterized by UV-Vis spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and N-2 adsorption-desorption measurements. The hydrophilicity of films was assessed by water contact angle technique. The results revealed that the surfactant-assisted sol-gel films were homogeneous, crack-free, contained anatase phase only with small grain size, and showed an increase in BET surface area and wide range of pore size distribution compared to non-surfactant treated sample. The optical properties and photocatalytic activity of the films for an azo dye, Plasmocorinth B (PB) degradation were analyzed with UV-Vis spectrometer. The photocatalytic activity of the synthesized anatase TiO2 films having high optical quality is comparable to the activity of reference commercial powder P25 films. Relevant results are presented and discussed as a function of the structure and morphology of coatings, which control enables a direct tailoring of the functional response. The high porosity, uniformity, transparency, reliability, photocatalytic activity, good adhesion with the substrate and the excellent performance under cycling operation displayed by surfactant-assisted anatase TiO2 coatings make it a good candidate to be considered in new emerging engineering applications. (C) 2011 Elsevier B.V. All rights reserved.