Mainz 2017 – wissenschaftliches Programm

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MS: Fachverband Massenspektrometrie

MS 5: Cluster

MS 5.2: Vortrag

Dienstag, 7. März 2017, 15:45–16:00, RW 2

Room-temperature methane activation by tantalum (oxide) clusters — •Jan Frederik Eckhard, Tsugunosuke Masubuchi, Daniel Neuwirth, Martin Tschurl, and Ueli Heiz — Technical University of Munich, Chair of Physical Chemistry, Lichtenbergstraße 4, 85748 Garching, Germany

The selective transformation of methane has received a lot of attention as it is one of the most important reactions that require C-H bond activation. Unraveling the mechanistics of such complex processes is facilitated in gas-phase studies. In our setup, the combination of a laser vaporization cluster source, a cryogenic ring electrode ion trap and a reflectron time-of-flight mass spectrometer is used to analyze reactions of size-selected metal clusters under multi-collision conditions. Doing so, reaction pathways as well as size-dependent apparent rate constants and activation energies are obtained. Additional information, e.g. about intrinsic cluster properties, may be revealed by employing ab-initio calculations. Tantalum was chosen as a clustering material as it is one of the few metals that, in its atomic cation form, brings about hydrogen elimination from methane. Cationic tantalum clusters and tantalum oxide clusters are also found to activate methane in consecutive dehydrogenation reactions. These new results will be presented in detail and surprising findings concerning cluster size, composition and activation energies will be discussed.