TiO2 photocatalysts deposited on activated carbon (TiO2/AC) were prepared by dip-hydrothermal method at 180 degrees C using peroxotitanate as a precursor, then calcinated at 300-800 degrees C. The samples were characterized by X-ray diffraction, scanning electron microscopy, Raman spectroscopy and the nitrogen absorption. Their photocatalytic activity was evaluated by degradation of methyl orange ( O). The results showed that TiO2 particles of anatase type were well deposited on the activated carbon surface. TiO2/AC calcinated at 600 degrees C exhibited the best photocatalytic performance. For the comparison, the same photocatalysis experiment was carried out for two mixtures of commercial TiO2 (Degussa P25) with AC and synthetic TiO2 with AC. It was found that the composite catalyst TiO2/AC was better than the two mixtures. Besides, different from. ne powdered TiO2, the granular TiO2/AC photocatalysts could be easily separated from the bulk solution and reused; indeed, its photocatalytic ability was hardly decreased after a five-cycle for MO degradation. The kinetics of the MO degradation fitted well the Langmuir-Hinshelwood model. (C) 2008 Elsevier B. V. All rights reserved.