Effect of Various Supports on the Catalytic Performance of V-Sb Oxides in the Oxidative Dehydrogenation of Isobutane

V0.9Sb0.1Ox systems, bulk and deposited on different supports (five types of gamma-aluminas, alpha-alumina, silica-alumina, silica gel, magnesium oxide), have been tested in the oxidative dehydrogenation (ODH) of iso-butane. Catalytic performance of VSb oxides has shown to be highly dependent on the support and the nature of the support decreasing in a series: gamma-Al2O3 > alpha-Al2O3 > Si-Al-O > SiO2 approximate to MgO >> unsupported. Variation of the V-Sb-O-loading in the studied range of coverage (0.5-2 theoretical monolayer) only slightly influences the catalysts' activity and selectivity. The best catalytic performance of gamma-alumina-supported V0.9Sb0.1Ox systems can be explained by the optimal surface interaction between support and supported components resulting in the formation of well-spread amorphous active VOx-component with vanadium in a high oxidation state.