Photoactivity of nanostructured TiO2 catalysts in aqueous system and their surface acid-base, bulk and textural properties

This work reports on the characterisation and determination of the photocatalytic activity of some TiO2 catalysts prepared using TiCl4 as precursor. The samples, consisting of suspensions, dispersions or powders of nanostructured anatase or rutile phases, were obtained in very mild conditions, i.e., by boiling the solution obtained after hydrolysis of TiCl4 at atmospheric pressure; it is worth noting that no calcination was necessary to obtain photoactive phases. The samples were characterised by X-ray diffraction (XRD), determination of the BET specific surface area (SSA), scanning electron microscopy (SEM) observations and diffuse reflectance spectroscopy (DRS). FT-IR spectroscopy was used to study the surface acidity of the solids. Photodegradation of 4-nitrophenol and gemfibrozil (5-(2,5-dimethylphenoxy)-2,2-dimethyl-pentanoic acid) was used as probe reactions to evaluate the photoactivity and the obtained results showed that the home prepared samples are effective to degrade both substrates. The photoreactivity results were compared to those obtained using commercial photocatalysts.