Sodium decatungstate-zirconia (Na4W10O32/ZrO2) nanocomposite was prepared through entrapment of Na4W10O32 into zirconia matrix by a sol-gel route. This new nanocomposite was characterized by means of X-ray diffraction (XRD), Fourier-transformed infrared spectroscopy(FT-IR), UV-vis spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy(TEM) and Surface area measurement. The nanocomposite was used as a green and recyclable heterogeneous photocatalyst for rapid and efficient reductive cleavage of azobenzenes into their corresponding amines with 2-propanol as a hydrogen donor at room temperature under N-2 atmosphere. The reductive cleavage occurs without hydrogenolysis or hydrogenation of reducible moieties, Such as -NO2, -OH, -CH3, -OCH3, -COOH, -COCH3, halogen and -CN. The photocatalyst has been reused several times, without observable loss of activity and selectivity. According to the azobenzene reduction, the Na4W10O32/ZrO2 nanocomposite is more effective as a photocatalyst than pure Na4W10O32, showing that the nanocomposite approach could be an excellent choice to improve the photoactivity of POMs. (C) 2009 Elsevier B.V. All rights reserved.