Heidelberg 2015 – wissenschaftliches Programm
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MS: Fachverband Massenspektrometrie
MS 4: Ion Traps, Molecules, Clusters, Decay and Reactions
MS 4.6: Vortrag
Dienstag, 24. März 2015, 12:30–12:45, PH/HS2
Size-dependent gas phase reactivity of tantalum cluster cations with small alcohols — •Jan Eckhard1, Daniel Neuwirth1, Kathrin Lange1, Bradley Visser2, Martin Tschurl1, and Ueli Heiz1 — 1Lehrstuhl für Physikalische Chemie & Catalysis Research Center, Chemistry Department, Technische Universität München, Lichtenbergstraße 4, 85748 Garching bei München, Germany — 2Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
As the properties of metal clusters may change vastly as a function of cluster size, their study is a model approach to find and tune catalysts for use in specific reactions. The detailed investigation of metal clusters is facilitated in the gas phase. As a result, we found a strong size dependence for the reactivity of tantalum cluster cations with small alcohol molecules. The clusters were produced in the gas phase by laser vaporization; various alcohols (methanol, ethanol, n-propanol and 2-propanol) were consecutively added to the cluster beam in a pulsed jet and allowed to react to an extent of conversion of approximately 50 %. The charged reaction products were subsequently measured using time-of-flight mass spectrometry. Two distinct reaction pathways were observed, involving complete dehydrogenation or OH abstraction from the alcohol molecule. The relative total reaction yield was found to not vary significantly within the cluster size regime studied. The branching ratios for the reaction demonstrated a cluster-size dependence, with a minimum of OH abstraction occurring for a cluster size of 7 atoms.