A sol-gel hydrothermal method was developed to synthesize peroxo-titania powders and their photo-oxidation performances were conducted in aqueous methanol solution under visible light irradiation. Three kinds of peroxo-titania were developed using TiO2 and H2O2 containing precursor sol with different dispersion mediums such as NH3 aq NaOH aq, or pure water. Peroxo-titania powder prepared with NH3 aq showed highest photooxidation activity. Moreover, we found unique photofunctional properties: together with formaldehyde production, the photo-excited electron also triggers oxygen evolution, although by TiO2 (Degussa P-25) photocatalysis H-2 evolution was observed from the same solution. (C) 2008 Elsevier Inc. All rights reserved.