Nanocrystalline titania with particle size similar to20-50 nm and specific surface area similar to20-80 m(2)g(-1) is prepared by hydrothermal treatment of aqueous TiOSO4, H2TiO(C2O4)(2), and TiO(NO3)(2) solutions. The photocatalytic behavior of synthesized TiO2 powders is studied in the reaction of phenol photodegradation in water and optimal characteristics of these materials are explored. The best photocatalytic activity was observed for a mixture of rutile (15%) and anatase (85%) prepared by high-temperature hydrolysis of aqueous TiOSO4 solution. (C) 2004 Elsevier B.V. All rights reserved.