Regensburg 2022 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 56: Poster Wednesday: Nanostructures 2
O 56.2: Poster
Mittwoch, 7. September 2022, 18:00–20:00, P4
Charge effects on the (de-)Hydrogenation activity of Ptn-clusters on a-SiO2 thin films — •Tobias Hinke1, Andrew Crampton1, Marian Rötzer1, Maximilian Krause1, Florian Schweinberger1, Bokwoon Yoon1, Uzi Landman2, and Ueli Heiz1 — 1Physical Chemistry, Department of Chemistry & Catalysis Research Center, Technical University of Munich, 85748 Garching, Germany — 2School of Physics Georgia Institute of Technology, Atlanta GA, U.S.A.
Catalytic model systems facilitate the gain of fundamental insights on molecular mechanisms and enable atom-precise manipulation of catalytic processes. Besides the size-effects of clusters with less than 100 atoms, the influence of the supporting material and the substrate are of special interest when steering reactivity.
The catalyst’s local electron density can be altered by varying the underlying metal. A high local work function of the substrate, Mo(112), yields clusters of positive charge while a low local work function , Pt(111), results in a negative charge. This allows for specifically altering the reactivity as well as the coking stability of the catalytic system.
In order to elucidate the impact of different support materials as well as cluster size-effects the change in activity of a-SiO2 thin-film supported Ptn-clusters towards ethylene (de-)hydrogenation was investigated.
The catalytic samples were characterized in a UHV setup with base pressures below 5*10−10 mbar through IRRAS and electron spectroscopy (XPS, MIES, UPS), while reactivity was monitored with TPD and pulsed valve experiments (p-MBRS).