Abstract

Small titania particles were generated within the template of a non-ionic surfactant (TX-100) reverse micelle assembly by the sol–gel method from titanium(IV) isopropoxide. Cyclohexane was used as the reaction solvent to form a reverse micelle system with a low water to surfactant ratio. Gelling, i.e., hydrolysis and polycondensation, were observed by means of viscosity measurements. The transparent raw gels obtained were dried under vacuum at 372 K. The dry gels were then either thermally decomposed directly to TiO₂ or the organic content (surfactant) was substantially reduced first by supercritical fluid extraction with CO₂ and then thermally treated. Special attention was paid to the effect of temperature on the extent of crystallisation of individual crystallographic phases of TiO₂. Gels, partly decomposed gels and gels after the supercritical fluid extraction were investigated by XRD, XPS, IR, TPR, thermogravimetry, mass spectrometry, elemental analysis, UV–vis, SEM and extensive gas adsorption measurements. Their properties were related to the structure and other features of the final nanosized TiO₂ particles. The anatase form of TiO₂ with a very high specific surface area and well-developed mesoporous and microporous structure was prepared.