Zirconia-supported Keggin phosphomolybdovanadate nanocomposite: A heterogeneous and reusable catalyst for alkene epoxidation under thermal and ultrasonic irradiation conditions

Keggin phosphomolybdovanadate, PVMo, was supported on a zirconia matrix by the wet impregnation method. The phase and chemical structure, optical absorption, surface physicochemical properties and morphology of PVMo-ZrO2 composite were studied by X-ray diffraction (XRD) technique, FT-IR and diffuse reflectance UV-vis spectroscopic (DR UV-vis) methods, and scanning electron microscopy (SEM), which indicated that the primary Keggin structure has remained intact after formation of the composite. Moreover, the obtained nanocomposite was used as an efficient catalyst of olefins under reflux and ultrasonic irradiation conditions. The catalyst was reused several times, without observable loss of activity and selectivity. Indeed, the catalytic activity of the PVMo-ZrO2 was compared with pure Keggin phosphomolybdovanadate. (C) 2011 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.