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MO: Molekülphysik
MO 56: Poster: Molecular Clusters
MO 56.5: Poster
Donnerstag, 16. März 2006, 16:30–18:30, Labsaal
Reactivity and Infrared Spectroscopy of mass selected vanadium oxide cluster ions — •Mathias Brümmer1, Jens Döbler2, Sara Fontanella1, Gabriele Santambrogio1, Joachim Sauer2, Ludger Wöste1, and Knut Asmis3 — 1Freie Universität Berlin, Institut für Experimentalphysik, Arnimallee 14, 14195 Berlin — 2Humbold Universität Berlin, Institut für Chemie, Unter den Linden 6, 10099 Berlin — 3Fritz Haber Institut der Max Planck Gesellschaft, Abteilung Molekülphysik, Faradayweg 4-6, 14195 Berlin
Despite the enormous importance of transition metal oxides based catalysts very little is known about their microscopic details. Vanadium oxides catalyze the oxidation of SO2 to SO3, an important step in the production of sulfuric acid. We performed experiments in which we spectroscopically followed the reaction of vanadium oxide anions (V2O5)n−, for n=2 to 4, with sulfur dioxide via infrared multiphoton photodissociation. All spectra show absorption bands in both the vanadyl and the V-O-V region of the spectrum. Differences in the spectra of the bare vanadium oxide anions were interpreted as a consequence of size-induced localization of the extra electron. The spectra measured after SO2 absorption indicate a chemisorption of sulfur dioxide. Recent calculations on [V4O10SO2]− indicate that here SO2 is inserted into the vanadium oxide cage. For the larger systems the vanadyl bond on which the extra electron is locaded seems to be the active site. Here a chemical reaction between the vanadyl-oxygen and SO2 to SO3 is expected.