Bimodally mesoporous titania was prepared by hydrolysis of titanium tetraisopropoxide in pure water or the EtOH-H2O mixed solution under ultrasonic irradiation. Effects of alcohol content and calcination temperature on the phase composition and porosity of bimodally mesoporous titania was investigated by thermogravimetric and differential thermal analysis (TG-DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) surface areas. The results showed that for all TiO2 powders calcined from 400 to 600 degreesC, the pore size distribution is bimodal with fine intra-particle pore diameter at maximum pore diameters of ca. 2-4 nm and larger inter-particle pore diameter at maximum pore diameters of ca. 18-50 nm. The EtOH/H2O molar ratios obviously influenced the crystallization, crystallite size, BET surface areas, porosity and morphology of the prepared TiO2 powders. (C) 2003 Elsevier B.V. All rights reserved.