Photoexcitation of Na4W10O32 dissolved in water leads to the formation of hydroxyl radicals. These species originate both from H2O oxidation and H2O2 reduction. EPR-spin trapping investigation and laser flash photolysis experiments contribute to clarify their formation mechanism and their involvement in the oxidation of propan-2-ol. Continuous irradiation of water solutions of Na4W10O32 leads to the overoxidation of propan-2-ol to CO2 with high yield. This result may be of interest for the development of photocatalytic systems aimed to pollutants degradation. Entrapment of Na4W10O32 into a microporous silica matrix gives a rather robust photocatalyst where the decatungstate structure is preserved. This material is able to catalyze the photooxidation of propan-2-ol to acetone with appreciable chemoselectivity. In particular, it is seen that the solid photocatalyst yields acetone as main product inhibiting its over-oxidation to carbon dioxide. (C) 2013 Elsevier B.V. All rights reserved.