Nanocrystalline titanium dioxides (TiO2) prepared from (a) titanium tetrachloride (TiCl4) and (b) titanium tetraisopropoxide (TTIP) have been compared. The effect of the reaction parameters on the phase formation of TiO2 was investigated systematically. For TiO2 prepared by hydrolysis of TiCl4, the crystal phase changed with the speed of TiCl4 addition and slow addition favoured the formation of rutile. For TiO2 prepared by hydrolysis of Ti(OC3H7)(4), the reduction in hydrolysis rate associated with lower reaction temperatures promoted rutile formation. For both TiCl4 and TTIP derived samples, increasing the anatase content decreased the measured rate of photocatalytic oxidation of isopropanol to acetone. (C) 2012 Elsevier B.V. All rights reserved.