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O: Oberflächenphysik
O 13: Postersitzung (Adsorption auf Oberfl
ächen, Oberfl
ächenreaktionen, Elektronische Struktur, Epitaxie und Wachstum, Halbleiteroberfl
ächen und Grenzfl
ächen, Oxide und Isolatoren)
O 13.89: Poster
Montag, 26. März 2001, 19:00–22:00, Foyer zu B
Imaging the interaction of sulfur dioxide with a TiO2(110) surface at 300 K by scanning tunneling microscopy — •Nils Hartmann1,2, Jürgen Biener1,3, and Robert J. Madix1 — 1Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA — 2Institut für Physikalische und Theoretische Chemie, Universität Essen, D-45117 Essen — 3Bayerisches Geoinstitut, Universität Bayreuth, D-95440 Bayreuth
Scanning tunneling microscopy (STM) was used to study the interaction of sulfur dioxide with the bulk-terminated (1x1) and the reconstructed (1x2) structure of the TiO2(110) surface at 300 K. During exposure new features appear first on the added rows of the reconstructed (1x2) surface structure. In general these new features are randomly distributed. However, in some areas locally ordered linear structures can be observed along the (1x2) rows with a periodicity two or three times higher than the substrate. In contrast, additional features on the (1x1) structure can be seen only after higher SO2 exposure. Here, an ordered adsorbate phase with a (2x1) structure is formed. The new features of this (2x1) structure are located on top of the (1x1) rows along the [001] direction, which previously have been shown to represent the five-fold coordinated Ti surface cations. Point defects on the stoichiometric (1x1) surface structure as well as on the reconstructed (1x2) surface structure are unaffected by SO2 exposure.