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O: Fachverband Oberflächenphysik

O 36: Particles and clusters

O 36.7: Vortrag

Mittwoch, 25. März 2009, 16:30–16:45, SCH A01

Reaction of Cu and Au clusters with single crystalline ZnO surfaces — •Martin Kroll, Thomas Löber, and Ulrich Köhler — Experimentalphysik IV / AG Oberflächenphysik, Ruhr-Universität Bochum, 44780 Bochum, Germany

As model systems in heterogeneous catalysis metal clusters on single ZnO-crystals grown in UHV are used as a first step to understand the complex reactions under real catalytical conditions. STM and SEM were used to examine nucleation and thermal behaviour of the systems Cu/ZnO(0001)-Zn, Au/ZnO(0001)-Zn and Cu/ZnO(1010) up to 500^∘C. Cu and Au were deposited using MBE. Additionally a CVD-source was used for Cu-deposition. On the polar ZnO(0001) surface and on the mixed terminated ZnO(1010) surface separated clusters are formed at room-temperature and a partial entrenching of Cu into the ZnO substrate at elevated temperatures of T≥400^∘C was found[1]. In contrast, Au on ZnO initially forms a closed layer at room-temperature and annealing to comparable temperatures shows a pile-up of Au-material into a network of connected island without any reaction with the ZnO-support.

[1] M.Kroll, U. Köhler; Surf. Sci 601 (2007) 2182