Temperature-dependent oxygen release, intercalation behaviour and catalytic properties of V 2O 5· xNb 2O 5 compounds

Abstract

In order to investigate the catalytic properties, V 2,38Nb 10,7O 32,7, VNb 9O 25 and solid solutions of V 2O 5 in TT-Nb 2O 5 were prepared by thermal decomposition of freeze-dried oxalate precursors. The samples were characterised by X-ray diffraction and surface area determination. The crystalline samples are capable of the intercalation of sodium and lithium ions from solution. Above a temperature of about 500 °C, in dependence on the oxygen partial pressure a reversible release and uptake of oxygen without a structural variation takes place. The catalytic properties have been evaluated for the oxidative dehydrogenation (ODH) of propane and propene. There are only small differences in the catalytic activity of the different crystalline samples. Because of the relative high starting temperature, a selective catalytic oxidation of propane to propene is hardly observed.