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 73.2: Hauptvortrag (ohne Erstattung)

Donnerstag, 28. Februar 2008, 14:30–15:00, MA 005

Molecular adsorption on bimetallic particles supported on well defined oxide surfaces — •Thomas Risse — Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin, Germany

The admixture of a second metal has proven to be a suitable method to tune the desired properties of solid-supported metal particles. This presentation will focus on the adsorption properties of molecules on nanometer-sized bimetallic particles deposited on single crystalline oxide films. Such systems can serve as model systems for heterogeneous catalysts, which allow investigations with the rigor of modern surface science while grasping essential aspects of the complexity of real catalytic systems. The adsorption properties of molecules on bimetallic particles depend on a variety of parameters such as elemental and surface composition, particle size, or metal substrate interaction. Co/Pd and Fe/Pd particles grown by physical vapor deposition on a well defined alumina film will be used as model systems to explore the dependence of the adsorption properties on the abovementioned parameters. The experiments take advantage of the nucleation properties of the different metals which allow -by appropriate deposition conditions- to tune the particle's surface composition, shape, or degree of crystallinity. To allow for a microscopic analysis of the observed effects, investigations of the adsorption properties will be amended by structural characterization of the systems. Furthermore experiments on simple reactions such as reaction of the systems with oxygen or methanol decomposition will be discussed with respect to their susceptibility to the admixture of a second metal component.