Berlin 2008 – scientific programme

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O: Fachverband Oberflächenphysik

O 88: Metallic Nanostructures II (on Semiconductors)

O 88.4: Talk

Friday, February 29, 2008, 10:15–10:30, MA 005

Enhanced Bonding of Gold Nanoparticles on Oxidized TiO2(110) — •Stefan Wendt, Daniel Matthey, Jianguo Wang, Jesper Matthiesen, Renald Schaub, Erik Laegsgaard, Bjørk Hammer, and Flemming Besenbacher — Interdisciplinary Nanoscience Center (iNANO), and Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C, Denmark

We studied the nucleation of gold clusters on TiO2(110) surfaces in three different oxidation states by high-resolution scanning tunneling microscopy (STM). The three TiO2(110) supports chosen were (i) reduced having bridging oxygen vacancies, (ii) hydrated having bridging hydroxyl groups, and (iii) oxidized having oxygen ad-atoms. At room temperature gold clusters nucleate homogeneously on the terraces of the reduced and oxidized supports, whereas on the hydrated TiO2(110) surface clusters form preferentially at the step edges [1]. From interplay with density functional theory (DFT) calculations, we identified two different gold-TiO2(110) adhesion mechanisms for the reduced and oxidized supports. The adhesion of gold clusters is strongest on the oxidized support, and the implications of this finding for catalytic applications are discussed.

[1] Matthey, D.; Wang, J. G.; Wendt, S.; Matthiesen, J.; Schaub, R.; Laegsgaard, E.; Hammer, B.; Besenbacher, F., Science, 315, 1692 (2007).