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O: Fachverband Oberflächenphysik

O 45: Poster: Solid-Liquid Interfaces - Structure, Spectroscopy, Reactions and Electrochemistry

O 45.16: Poster

Tuesday, March 13, 2018, 18:15–20:30, Poster A

Electro-oxidation of CO on Au modified planar and nanostructured Pt(111) electrodes — •Evelyn Artmann, Julian Bösking, Jens Klein, Valeria Chesnyak, Albert K. Engstfeld, and R. Jürgen Behm — Ulm University, Institute of Surface Chemistry and Catalysis, D-89069 Ulm

The catalytic activity of Platinum (Pt) for the oxidation of CO was shown to increase with increasing amount of low coordinated Pt sites, like Pt step edges, on the surface which may be more active compared to terrace sites.^[1] The exact role of step sites in the reaction mechanism is, however, still under debate. A strategy to identify the role of Pt steps in the CO oxidation is to block the steps by decorating them with a narrow Au film and then to compare the activity of the electrode with and without Au decoration. Prior to this it is, however, important to investigate the stability of such Au films on Pt as well as the influence of the Au film on Pt terrace sites for the CO oxidation activity. To this end, we first prepared and structurally characterized, by STM under UHV conditions, Pt(111) single crystals with varying Pt step densities. Subsequently, we decorated the Pt steps with monolayer high Au films and varied the Au coverage from sub-monolayer to full monolayer coverage. Investigating the structural characteristics of the surfaces before and after CO oxidation, as measured in an electrochemical flow cell, provided us information about the electrode stability under reaction conditions and about the influence of the Au film at Pt step and terrace sites on the activity of the electrodes for CO oxidation. [1] G. García et al., ChemPhysChem. 12 (2011) 2064.