A photocatalyst that may exhibit high activity for oxidation of volatile organic compounds (VOCs) under solar radiation would offer a practical and economic means for the cleaning of air under environmental conditions. We report here for the first time that the uranyl ions anchored within the mesopores of MCM-41 may serve as an efficient heterogeneous photocatalyst for the complete destruction of methanol in vapor phase, and in the presence of sunlight and air. The uranyl-anchored MCM-41 was found to be more efficient than a TiO2 photocatalyst in terms of CH3OH-->CO2 conversion rates. The reversible and active participation of uranyl groups in the studied photocatalytic reaction was ascertained with the help of in situ fluorescence and electron paramagnetic resonance techniques, whereas the radiation-induced transient species over catalyst surface were monitored using in situ FTIR spectroscopy. The detailed reaction mechanism and the role played by uranyl ions in the photooxidation of methanol over UO22+/MCM are elucidated on the basis of these results. (C) 2004 Elsevier B.V. All rights reserved.