Oxidative Dehydrogenation of Ethane over Sn-W-Ox Catalysts

The oxidative dehydrogenation of ethane to ethene was investigated over the catalyst composed of tin and tungsten oxides at 923 K under atmospheric pressure. A pure SnO2 catalyst showed the high ethane conversion but low ethene selectivity (the major product was carbon dioxide). On the other hand, a pure WO3 catalyst showed the high ethene selectivity while the ethane conversion was relatively low. The remarkable synergetic effect of tin and tungsten was observed when Sn2W3O8 was used as catalyst precursor. According to the XRD measurement, Sn2W3O8 was found to decompose into SnO2 and WO3 after the reaction, however, no significant difference was observed in the XPS analysis for tin and tungsten between the samples before and after the reaction. To clarify the synergism of tin and tungsten in Sn2W3O8, the Auger parameter was employed for the surface oxygen atom of the catalyst. The clear relationship was found between the ethene yield and the ionicity of the oxygen atom.