Characterisation of vanadium-oxide-based catalysts for the oxidative dehydrogenation of propane to propene

The study is based on the previous development of α-Al2O3-supported multi-metal-oxide materials for oxidative dehydrogenation of propane by applying a combinatorial approach (773 K, ambient pressure, a feed composition of C3H8 : O2 : N2=30 : 10 : 60 and 40 : 20 : 40). For further improvement of catalytic materials, fundamental insights were derived from oxygen transient experiments and XRD as well as XPS studies. Fitting transient experiments showed that irreversible and dissociative adsorption on two active centers provides a good description of the transient oxygen responses over all the catalytic materials studied. The composition of these materials influenced strongly the apparent first-order rate constant of oxygen activation. Based on the characterisation data it was found that an optimal bulk concentration (2.6–8.3 wt%) of VOxspecies on the support and their distribution on the surface are an essential requirement for the selective oxidative dehydrogenation of propane to propene.