Vanadium supported on hexagonal mesoporous silica:: active and stable catalysts in the oxidative dehydrogenation of alkanes

Hexagonal mesoporous silica (HMS) catalysts post-synthetically doped with vanadia oxo-species were characterized by means of XRD, UV-Vis spectroscopy, H(2)-TPR and studied in oxidative dehydrogenation of propane (ODH). The relationship between catalytic activity in ODH and the presence of different vanadia-oxo species (monomeric, oligomeric and oxide-like species) was suggested. Monomeric VOx species are responsible for high catalytic activity and selectivity, oligomeric species containing V-O-V bond are active but non-selective to propene and oxide-like VOx particles are significantly less active and selective.