Berlin 2008 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 73: Symposium: Bimetallic Nanosystems: Tuning Physical and Chemical Properties II (Invited Speakers: André Fielicke, Thomas Risse, Jürgen Behm)
O 73.10: Vortrag
Donnerstag, 28. Februar 2008, 17:15–17:30, MA 005
UPS investigations of ultrathin Au films deposited on Pd(110) — •Marco Moors1, Tomasz Kobiela1, Marko Kralj2, Tobias Pertram1, Conrad Becker1, and Klaus Wandelt1 — 1Institute of Physical and Theoretical Chemistry, University of Bonn, Germany — 2Institute of Physics, University of Zagreb, Croatia
The surface morphology and the local electronic properties of ultrathin Au films deposited on Pd(110) under UHV conditions have been studied by ultraviolet photoelectron spectroscopy and related methods. Investigations of bimetallic systems concerning morphology and adsorption properties are of great interest for the development of new catalysts with higher efficiency and durability. Our UPS and PAX experiments verified former STM studies [1] which showed a strong temperature dependence of the surface morphology. The Au-Pt surface prepared at 150 K is already quite flat and undergoes only a weak smoothening by annealing to 250 K. At a surface temperature of * 600 K gold starts to diffuse into the bulk forming a well ordered Au-Pd surface alloy with a maximal alloy concentration on the surface reached at 850 K. At an annealing temperature of 1050 K the surface gold depletion is completed. Besides the characterization of the Au-Pt system several adsorption experiments with various catalytic relevant molecules like CO and methanol have been performed.
[1] M. Kralj, A. Bailly, M.-C. Saint-Lager, S. Degen, A. Krupski, C. Becker, P. Dolle, M. De Santis, K. Wandelt; Surf. Sci. 600 (2006) 2614.