Activity and selectivity of propane oxidative dehydrogenation over VO3/CeO2(111) catalysts: A density functional theory study

Abstract

The oxidative dehydrogenation (ODH) of propane on monomeric VO3 supported by CeO2(111) (VO3/CeO2(111)) is studied by periodic density functional theory calculations. Detailed energetic, structural, and electronic properties of these reactions are determined. The calculated activation energies of the breaking of the first and second C–H bonds of propane on the VO3/CeO2(111) catalyst are compared, and it is found that both the unique structural and electronic effects of the VO3/CeO2(111) catalyst contribute to the relatively easy rupture of the first C–H bond of the propane molecule during the ODH reaction. In particular, the so-called new empty localized states that are mainly constituted of O 2p orbitals of the ceria-supported VO3 species are determined to be crucial for assisting the cleavage of the first C–H bond of the propane molecule. Following this they become occupied and the remaining C–H bonds become increasingly difficult to break owing to the increasing repulsion between the localized 4f electrons at the Ce cations, resulting in the adsorption of more H and other moieties. This work illustrates that CeO2-supported monomeric vanadium oxides can exhibit unique activity and selectivity for the catalytic ODH of alkanes to alkenes.