Porous TiO2 microspheres with specific surface areas in the range of 159.4-265.4 m(2)/g, have been synthesized by a facile hydrothermal method. The sizes of prepared porous TiO2 microspheres are 1-5 mu m composed of tiny nanoparticles with a size of 1-7 nm. The influence of the reaction time and temperature on the formation of porous TiO2 microspheres has been investigated in detail and the possible growth mechanism is proposed. The photocatalytic activity of porous TiO2 microspheres has been carried out by the degradation of gaseous benzene. The results indicate that, comparing with commercial TiO2 (Degussa P25), TiO2 microspheres as-prepared exhibit significant photocatalytic activity, which could be due to their high adsorptive capacity that enhances the subsequent photocatalytic reactions and leads to a positive synergistic effect. (C) 2011 Elsevier B.V. All rights reserved.