Berlin 2008 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 49: Particles and Clusters

O 49.10: Vortrag

Mittwoch, 27. Februar 2008, 17:30–17:45, MA 005

Structure and properties of Au on nanostructured ceria — •Martin Baron, Dario Stacchiola, Shamil Shaikhutdinov, and Hajo Freund — Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany

It is well established that oxide supported gold nanoparticles catalyse CO oxidation at temperatures as low as 200 K [1]. Among those reported in the literature, gold catalysts supported on the cerium oxide (CeO2) often show a superior activity, in particular when ceria is present as nanoparticles [2]. To date, there are still open questions regarding the reaction mechanism and the nature of active species. In particular, the role of cationic (Au3+, Au+) species in this reaction remains unclear. Herein, we will present combined STM, XPS, LEED and IRAS studies of gold particles deposited on both extended CeO2 films and ceria nanoparticles. Well ordered CeO2 films were grown on Ru(0001) single crystal, and the quality of the films was controlled by XPS, LEED and STM. The ceria nanoparticles were prepared on thin silica films, which are essentially inert towards Au and CO, such that Au was only nucleated on the ceria particles and CO adsorbed only on Au/ceria. The results are rationalized on the basis of highly defective surface of nanoceria, which modifies the electronic structure of gold. [1] M. Haruta, N. Yamada, T. Kobayashi, and S. Iijima, J. Catal., 115 (1989) 301 [2] Carrettin S., Concepción P., Corma A., López Nieto J.M., Puntes V.F. (2004) Angew.