Supported Tantalum Oxide and Supported Vanadia-tantala Mixed Oxides: Structural Characterization and Surface Properties

From pure oxides over oxide-supported metal and bimetallic particles to mixed oxides: model systems for catalytic and structural studies

5 1 Conceptual approach 8 1.1 Scope of this thesis 8 1.2 Electronic and geometric effects in bimetallic catalysts 10 1.3 Mixed Oxides 11 1.4 (Strong) metal-support interaction 12 1.5 The role of the Pd-hydride phases 14 1.6 Oxide-supported Pd bimetallics in methanol steam reforming 14 1.7 Model Systems 21 2 Appendix: Experimental approach and methods 25 2.1 Electron Microscopy and related techn...

Alumina-supported vanadium nanoparticles: structural characterization and CO adsorption properties.

Alumina-supported vanadium particles were prepared under ultrahigh vacuum (UHV) conditions and characterized with respect to their structural and CO adsorption properties. As supporting oxide, we used a thin, well-ordered alumina film grown on NiAl(110). This allows the application of scanning tunneling microscopy (STM), infrared reflection-absorption spectroscopy (IRAS), and X-ray photoelectro...

Selective oxidation of propylene over model supported V2O5 catalysts: Influence of surface vanadia coverage and oxide support

Molecular structure and reactivity of the Group V metal oxides

The physical, electronic and reactivity properties of bulk and supported Group V metal oxides (V, Nb, Ta and Db) were compared at the molecular level. Dubnium is a very short-lived element, ∼60 s, whose properties have not been extensively studied, but can be predicted from knowledge of the other members of the Group V metal oxides. Bulk V2O5 possesses platelet morphology with the active surfac...

Role of ceria in oxidative dehydrogenation on supported vanadia catalysts.

The effect of the suppport on oxidative dehydrogenation activity for vanadia/ceria systems is examined for the oxidation of methanol to formaldehyde by use of well-defined VO(x)/CeO(2)(111) model catalysts. Temperature-programmed desorption at low vanadia loadings revealed reactivity at much lower temperature (370 K) as compared to pure ceria and vanadia on inert supports such as silica. Densit...