Oxidative dehydrogenation of propane over V2O5/TiO2/SiO2 catalysts obtained by grafting titanium and vanadium alkoxides on silica

Oxidative dehydrogenation of propane on V2O5/TiO2/SiO2 catalysts, prepared by grafting, was investigated in the temperature range 673-773 K. The prepa red samples were characterised by X-ray diffraction (XRD), Fourier-transfor m infrared spectroscopy (FTIR), UV-VIS diffuse reflectance (DR UV-VIS), tem perature programmed reduction (TPR) and Oz chemisorption. Crystalline V2O5 was not revealed on any sample, although the dispersion of the surface spec ies steeply decreased with increasing vanadium loading. Non-isolated tetrah edral V5+ were present on the surface at any vanadium concentration. In the case of A(5) catalyst, the presence of octahedral vanadium species was als o observed. (C) 2001 Elsevier Science B.V. All rights reserved.