Berlin 2008 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 13: Heterogeneous Catalysis
O 13.5: Vortrag
Montag, 25. Februar 2008, 15:00–15:15, HE 101
Olefin conversions on supported Pd model catalysts: Molecular origins of selectivity towards isomerization and hydrogenation — •Wiebke Ludwig1, Björn Brandt1, Jan-Henrik Fischer1, Swetlana Schauermann1, Francisco Zaera2, and Hans-Joachim Freund1 — 1Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin — 2University of California, Riverside, USA
Understanding the mechanisms governing alkene conversions, isomerization and hydrogenation in particular, is an important goal in catalytic research and significant for industrial processes.
Whereas no hydrogenation is observed on Pd single crystals, it was recently shown that hydrogenation readily occurs on small Pd particles, presumably due to the formation of weakly-bound subsurface hydrogen species [1].
Under realistic conditions, these reactions take place over catalysts covered with carbonaceous species originating from the decomposition of alkenes. The exact role of these strongly bound species is however still not clear.
In this study, we present results on the conversion of cis- and trans-2-butene with deuterium over a Pd model catalyst supported on a Fe3O4 oxide film. To investigate the influence of carbonaceous species on the reaction kinetics, we performed isothermal molecular beam experiments combined with TPD measurements on both clean and carbon-precovered catalysts.
[1] A.M. Doyle et al., Angew. Chem. Int. Ed. 2003, 42, 5240-5243.