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The molecular designed dispersion method is used to prepare supported transition metal oxide catalysts (Mo, Cu, V). The corresponding transition metal acetylacetonate complexes were reacted with silica or alumina, and subsequently thermally converted into the supported metal oxide. The deposition of these acetylacetonate complexes depends on the geometry and stability of the complex, the support properties and the synthesis procedure. By thorough control of the reaction parameters, this novel synthesis method enables the creation of uniform and highly dispersed supported transition metal oxides. Therefore, the molecular designed dispersion method plays an important role in the development of a new generation of catalysts. This paper is forwarded to the special issue of the Langmuir journal, devoted to the ISSHAC-3 symposium.

Silica-, alumina-, and zirconia-supported tantalum oxide and supported vanadia-tantala mixed oxide catalysts were investigated by XRD, UV-vis-DR, FTIR, and FT-Raman spectroscopy to determine the nature of the surface tantala species. Two types of surface TaO x species were identified. On the SiO 2 support, at low coverages tetrahedral TaO 4 species exist, with a TadO bond and three bridging Ta-O-support bonds. At higher coverages, octahedral TaO 6 species occur. On Al 2 O 3 and ZrO 2 both surface species exist already at considerably low Ta loading. The acidic properties of the catalysts were investigated by an FTIR study of adsorbed pyridine. Supported tantala is clearly more Lewis acidic in comparison to vanadia. The oxidation of methanol was used to probe the catalytic performance of the supported oxide species and from the activity and product distribution it is concluded that supported tantala predominantly shows acidic over redox behavior.

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The reaction of Fe(acac)3 with the surface of zirconia has been studied for the first time using in situ infrared diffuse reflectance spectroscopy, photoacoustic spectroscopy, and Fourier transform Raman spectroscopy. The unstable Fe(acac)3 reacts readily with the surface of zirconia at room temperature in the liquid phase or at 110 °C in the gas phase, yielding grafted Fe−OH species and Zr−acac surface groups. We present evidence that the reaction occurs both with coordinatively unsaturated Zr sites and with the surface hydroxyls. The grafted Zr−acac groups are thermally unstable and form Zr−acetate groups after thermal treatment at 110 °C in ambient air. After removal of the organic ligands, noncrystalline iron oxide species are formed on the zirconia surface. The grafting of iron oxide on zirconia is a relevant procedure to form either redox catalysts or solid-state fuel cells.