Berlin 2018 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 19: Solid-liquid interfaces: Reactions and electrochemisty II (joint session O/CPP)

CPP 19.2: Vortrag

Montag, 12. März 2018, 17:00–17:15, MA 144

Influence of Pt step sites on the electro-oxidation of CO — •Jens Klein, Valeria Chesnyak, Evelyn Artmann, Julian Bösking, Albert K. Engstfeld, and R. Jürgen Behm — Ulm University, Institute of Surface Chemistry and Catalysis, D-89069 Ulm

The performance of the CO electro-oxidation on Platinum (Pt) catalysts strongly depends on the surface structure of the catalyst. It has been reported that Pt electrodes with a large number of low coordinated step sites show an enhanced activity for the electro-oxidation of an adsorbed monolayer of CO, which was ascribed to active sites on the step edges.^[1]

In this work we investigated the role of Pt steps in the electro-oxidation of CO on Pt electrodes under continuous CO supply (bulk CO oxidation). We prepared Pt(111) single crystal electrodes and varied the Pt step edge density by physical vapor deposition of Pt on the crystal under UHV conditions. The structural properties were characterized by scanning tunneling microscopy (STM). To identify the actual role of Pt step edges we blocked the respective sites, by decorating the Pt steps with a narrow Au film, since Au supported on Pt(111) was reported to be inert for the CO oxidation.^[2] The electrocatalytic measurements, which were performed in an electrochemical flow cell, provide information on the role of the Pt steps in the CO oxidation and consequences of these findings will be discussed.

[1] G. García et al., ChemPhysChem. 12 (2011) 2064.

[2] D. C. Skelton et al., J. Phys. Chem. B, 103 (1999) 964.