Enhancement of Photocatalytic Activity of Sol-gel TiO₂ Thin Films With P25

Jerneja Šauta Ogorevc,^1,* Urška Lavrenčič Štangar² and Peter Bukovec¹

¹Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, SI-Ljubljana, Slovenia
²Laboratory for Environmental Research, University of Nova Gorica, Vipavska 13, SI-Nova Gorica, Slovenia
* Corresponding author: E-mail: neja.sauta@fkkt.uni-lj.si

Abstract
Semi-transparent TiO₂ thin films were prepared via sol-gel method using TiCl₄ as a precursor with an addition of various loadings of Degussa P25 powder. Thus prepared thin films were dip-coated on substrates, air dried and heat treated for 30 minutes at 500 °C to obtain uniform films with good adhesion to the substrate. Different substrates were used: SiO₂-coated soda-lime glass for photocatalytic experiments, aluminum foil for TG measurements and platinum foil to investigate the adhesion to various substrates. Thin films and the xerogels prepared from sols were characterized by different techniques, e.g. thermogravimetric (TG) analysis, differential scanning calorimetry (DSC), X-ray diffraction (XRD), UV–Vis spectroscopy, scanning electron microscopy (SEM), Fourier transform infrared (FT–IR) spectroscopy and contact angle measurements.
The addition of commercial TiO₂ P25 powder significantly increased the photodegradation rate of an aqueous solution of azo dye Plasmocorinth B, which was proved by in-situ UV–Vis spectroscopic measurements of the dye solution.

Keywords: TiO₂ thin films, TiCl₄ precursor, sol-gel, peroxo-modified sol, Degussa P25, photodegradation.