Berlin 2005 – wissenschaftliches Programm
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O: Oberflächenphysik
O 46: Adsorption an Oberfl
ächen V
O 46.8: Vortrag
Dienstag, 8. März 2005, 17:30–17:45, TU EB420
A comparative study of prenal on Pt(111), Pt2Sn(111) and Pt3Sn(111) surface alloys — •Jan Haubrich, Alexander Krupski, Conrad Becker und Klaus Wandelt — Inst. f. Phys. u. Theo. Ch., Wegeler. 12, D-53115 Bonn
It is known that the selectivity of the hydrogenation processes of α,β-unsat. aldehydes like acrolein or prenal depends not only on the molecule itself, but also on the catalyst employed. To understand the different selectivities, the adsorption of prenal on Pt(111) and two Pt-Sn surface alloys is investigated with HREELS, TPD and LEED.
After adsorption of prenal at 100K the desorption of fragments up to 100 amu is studied with TPD. While on Pt(111) the desorption of prenal is detected at 160K (Multilayer), 177K and 199K, also a fragmentation reaction is observed giving rise to desorption of H2 and CO in several peaks. On Pt2Sn and Pt3Sn surface alloys this fragmentation process is suppressed. HREELS experiments carried out between 100K and 500K on the three surfaces show highly complex spectra of adsorbed prenal. On Pt(111) also the fragmentation process starting at 300K can be examined with HREELS. Also on the PtxSn surfaces complex HREEL spectra of prenal are recorded.