A series of Mn-TiO2/SiO2 (silica gel loaded with manganese doped TiO2) photocatalysts have been prepared by sol-gel method, and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). Photocatalytic activities were enhanced in photocatalytic degradation of methyl orange over Mn-TiO2/SiO2. XPS analysis shows that a Ti-O-Si or Ti-O-Mn bond is formed on the surface of photocatalyst. Mn is doped as a mixture of Mn2+ and Mn3+ on the surface of 1.0 mol% Mn-TiO2/SiO2. Mn3+ appears to trap electrons and prohibit the electron-hole recombination. The electrons trapped in Mn3+ site are subsequently transferred to the adsorbed O-2. As a result, the combination of the electron-hole pair was reduced. (c) 2008 Elsevier B.V. All rights reserved.