Changes in Ceria-Supported Vanadium Oxide Catalysts during the Oxidative Dehydrogenation of Ethane and Temperature-Programmed Treatments

The effect of vanadium oxide loading on CeO2 support for ethane oxidative dehydrogenation (ODH) is studied. Surface vanadia species are highly dispersed on CeO2. The interaction with surface vanadia species significantly changes the structural and reactive properties of ceria support. VOx/CeO2 suffers an important change during ethane ODH due to a solid-state reaction between CeO2 and surface vanadia species resulting in the formation of CeVO4. Such a solid-state reaction is promoted by high temperature, high vanadium loading, and reducing environments. Raman in situ temperature-programmed studies under reduction and oxidation conditions reveal that the catalytic cycle involves oxidation−reduction of the Ce4+ ↔ Ce3+ species, while the V5+ species remain stable.