Regensburg 2007 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 68: Metal Substrates: Adsorption V
O 68.3: Vortrag
Freitag, 30. März 2007, 10:45–11:00, H39
Carbon monoxide adsorption sites on roughened Au(111) — •Tobias Nowitzki1, Wai-Leung Yim2, Mandus Necke3, Hanno Schnars3, Jürgen Biener4, Monika Biener4, Volkmar Zielasek1, Katharina Al-Shamery3, Thorsten Klüner2, and Marcus Bäumer1 — 1Institut für Angewandte und Physikalische Chemie, Universität Bremen — 2Institut für Reine und Angewandte Chemie, Theoretische Chemie, Universität Oldenburg — 3Institut für Reine und Angewandte Chemie, Physikalische Chemie, Universität Oldenburg — 4Lawrence Livermore National Laboratory
Since Au turned out to be an active catalyst for the oxidation of carbon monoxide, the adsorption properties on various Au surfaces have been studied. Interestingly, a comparable behavior has been revealed for a wide range of surfaces from supported particles to rough single-crystals: two desorption states above 100 K and one infrared signal. The atomistic origins for this behavior have not yet been clarified completely.
To study this effect, we prepared a rough surface by ion-bombarding a Au(111) single-crystal in ultrahigh vacuum and characterized the system by scanning tunneling microscopy, temperature-programmed desorption and infrared spectroscopy. Furthermore, density functional theory calculations were performed for a Au(332) surface exhibiting similar adsorption properties as the roughened Au(111). The results indicate that two distinct kinds of low-coordinated atoms can explain the experimental findings.