Berlin 2005 – wissenschaftliches Programm

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O: Oberflächenphysik

O 36: Postersitzung (Elektronische Struktur, Grenzfl
äche fest-flüssig, Halbleiteroberfl
ächen und -grenzfl
ächen, Nanostrukturen, Oberfl
ächenreaktionen, Teilchen und Cluster, Struktur und Dynamik reiner Oberfl
ächen)

O 36.63: Poster

Montag, 7. März 2005, 15:00–18:00, Poster TU F

Transport of matter with a chemical wave-the influence of alkali metals on catalytic surface reactions — •Hubertus Marbach^1,2, S. Günther^3,2, T. Neubrand², R. Hoyer², B. Luerßen², G. Lilienkamp⁴, Y. Suchorski^4,2, L. Gregoratti³, M. Kiskinova³, and R. Imbihl² — ¹Lehrstuhl für Pysikalische Chemie II, Universität Erlangen-Nürnberg, Egerlandstraße 3, D-91058 Erlangen — ²Institut für Physikalische Chemie und Elektrochemie, Universität Hannover, Callinstraße 3 - 3A, D-30167 Hannover — ³Sincrotrone Trieste, Italy — ⁴Institut für Physik und Physikalische Technologien, TU Clausthal

Heterogeneous catalysed reactions as O2+H2 and NO+H2 on Rh(110) are known for their ability to form spatiotemporal concentration patterns on the surface. In this work the influence of coadsorbed alkali metals (AM), namely K and Cs on these reactions were studied experimentally. It turned out that under certain reaction conditions a mass transport of AM occurs. Starting with an initial homogenous distribution of the AM this effect can lead to a condensation of stationary K-O concentration patterns during the O2+H2 reaction. Other selforganized patterns were found in the NO+H2 reaction. All experiments were carried out in UHV-chambers driven as continuous flow reactors. To clarify the underlying processes the following experimental methods were applied: LEEM, XPS, SPEM and PEEM. The driving force of the occurring selforganizing processes will be discussed by presenting experimental results showing chemical, electronic and structural aspects of the substrate and the involved reacting species.