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O: Fachverband Oberflächenphysik

O 60: Poster Session IV (Solid/liquid interfaces; Semiconductors; Oxides and insulators; Graphene; Plasmonics and nanooptics; Electronic Structure; Surface chemical reactions; Heterogeneous catalysis)

O 60.116: Poster

Mittwoch, 16. März 2011, 17:30–21:00, P4

In-situ spectroscopic investigation of adsorption and reaction of pyridine molecules on Pt surfaces — •Claudia Wöckel¹, Kristina Fischer¹, Andre Dorsch¹, Sandra Wickert¹, Regine Streber², Hans-Peter Steinrück², and Reinhard Denecke¹ — ¹Wilhelm-Ostwald-Institut, Universität Leipzig, Linnestr. 2, 04103 Leipzig, Germany — ²Physikalische Chemie II, Department Chemie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany

Using high-resolution and time-dependent XPS adsorption and reaction processes can be followed in-situ. We are applying this method to pyridine molecules adsorbed on Pt. Using a regularly stepped Pt(355) and a Pt(111) surface, C 1s and N 1s core level data are recorded during adsorption at various temperatures. As additional parameter, the free Pt terrace width is varied by deposition of Ag atoms on the surface, forming rows along the step edges at 300 K. Temperature-programmed XPS allows to follow the thermal reaction of the adsorbed species. The experiments have been performed at BESSY II in Berlin.

In line with literature reports about a temperature- and coverage-dependent reorientation from flat to upright[1], we observe changes in the core level binding energies and intensities during the uptake. Upon heating the strong N 1s feature observed at 200K is transformed into a contribution at higher binding energy. This is accompanied by respective changes in the C 1s data, suggesting again temperature- and coverage-dependent changes, here towards α -pyridyl. Supported by BMBF (05 ES3XBA/5).

[1] S. Haq, D.A. King, J. Phys. Chem. 100 (1996) 16957.