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O: Oberflächenphysik

O 26: Oxide und Isolatoren I

O 26.8: Vortrag

Samstag, 5. März 2005, 16:45–17:00, TU EB202

Reaction Kinetics on Oxide Supported Metal Nanoparticles: On the Role of Surface Oxygen, Subsurface Oxygen and Surface Oxides — •Tobias Schalow, Mathias Laurin, Swetlana Schauermann, Björn Brandt, Jörg Libuda, and Hans-Joachim Freund — Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin, Germany

The nature and formation of different oxygen species on iron-oxide supported Pd nanoparticles and their influence on catalytic reactions are investigated on well-defined supported model catalysts by combining molecular beam methods and various surface science techniques. IR reflection absorption spectroscopy of adsorbed CO is employed as a sensitive probe in order to identify the different adsorption sites on the metal particles and the support.

Remarkable differences are observed in comparison with previous studies on single crystal surfaces. For example it is found that the interaction with oxygen strongly depends on the particle size, involving e.g. reaction conditions under which the nanoparticle surface becomes only partially covered by surface-oxides. Moreover, the onset of surface-oxide formation is shown to be directly related to morphological transformations of the nanoparticles.