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O: Fachverband Oberflächenphysik

O 66: Nanostructures at surfaces III

O 66.5: Vortrag

Donnerstag, 29. März 2012, 11:30–11:45, MA 042

Pt(111) supported monolayer graphene as template for Pt nanoparticle formation. — Nadja E. Wagner, •Albert K. Engstfeld, and R. Jürgen Behm — Ulm University, Institute of Surface Chemistry and Catalysis, D-89069 Ulm, Germany

Recent investigations have shown that graphene monolayer films deposited on metal single crystal surfaces can be used as templates for the nucleation of periodic arrays of metal nanoparticles. These surfaces are promising model systems to study the electrocatalytic properties of very small metal nanoparticles. For the electrochemical measurements it is crucial that the graphene layer is perfectly closed to prevent electrooxidation and exposition of the substrate. It has been shown that graphene on Pt(111) can be grown,[1] the requirement of a closed layer, however, could not yet be fulfilled.

In this work the graphene layer was prepared by ethene exposure at elevated temperatures and different pressures in UHV. The properties of graphene monolayers on Pt(111) were studied by high resolution STM. We will show that it is possible to form a compact graphene layer on Pt(111) under these conditions. The ethylene pressure was found to play an important role on the homogeneity of the graphene layer. With increasing ethylene pressure the amount of domain boundaries rises due to an increasing number of smaller rotational domains. The homogeneity of the surface is checked by electrochemical measurments. Evaporation of Pt on gr/Pt(111) was investigated, and results will be presented.

[1] T. A. Land et al., Surface Science. 264, 1992, 261-270