Influence of solvent type on the characteristics and photocatalytic activity of TiO2 nanoparticles prepared by the sol-gel method

TiO₂ nanoparticles were prepared by the sol-gel method using methanol, ethanol and isopropanol as solvents and titanium tetraisopropoxide as a precursor. The prepared TiO₂ nanoparticles were characterised by X-ray diffraction, scanning electron microscopy, nitrogen physisorption and UV-vis diffuse reflectance spectroscopy. The results indicated that the TiO₂ nanoparticles prepared in isopropanol displayed pure anatase crystalline phase with the smallest crystallites having an average size of 11.4 nm. However, the TiO₂ nanoparticles prepared in methanol and ethanol contained anatase- and rutile-mixed phases with anatase crystallite sizes of 15.6 and 14.5 nm, respectively. Nitrogen physisorption results showed that, compared to the TiO₂ nanoparticles prepared with isopropanol, TiO₂ nanoparticles prepared with ethanol had a greater pore volume and pore size, which led to their higher photocatalytic activity. The photocatalytic activities of the prepared TiO₂ nanoparticles in the photodegradation of C.I. Basic Violet 2 (BV2) were compared to the activity of Degussa P25 TiO₂. The maximum photodegradation rate of BV2, obtained from the TiO₂ nanoparticles prepared in ethanol, was 3.5, 1.7 and 1.4 times greater than that of TiO₂ particles prepared in isopropanol and methanol and the commercial Degussa P25 TiO₂, respectively.