Dresden 2017 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 20: Solid-Liquid Interfaces: Reactions and Electrochemistry - Experiment I

O 20.3: Vortrag

Montag, 20. März 2017, 17:00–17:15, WIL B321

Electro-oxidation of CO on model electrodes – Atomic scale level nanostructures and their impact on the catalyst performance — •Jens Klein, Sylvain Brimaud, Valeria Chesnyak und R. Jürgen Behm — Ulm University, Institute of Surface Chemistry and Catalysis, D-89069 Ulm, Germany

The performance of electrocatalytic reactions, such as the CO oxidation, on monometallic and bimetallic Pt-based electrodes is highly sensitive towards the surface structure and surface composition of the catalyst on the atomic scale level.^[1] On Pt an increased activity for the CO oxidation was observed if the amount of monoatomic high Pt step edges increases, while on PtRu electrodes the appearance of adjacent Ru and Pt atoms in the surface were found to enhance the CO oxidation due to a bifunctional mechanism.^[1] For a more detailed understanding of the structure-activity relationship on the atomic scale level we studied the CO oxidation on single crystal model electrodes with well-defined nanostructured surfaces. Employing a combined ultrahigh vacuum (UHV) – electrochemical flow cell setup we prepared and structurally characterized by scanning tunneling microscopy (STM) under UHV conditions Pt(111) and Ru(0001), which were structurally modified on the atomic scale, e.g., by varying the Pt step edge density or the number of adjacent PtRu-sites followed by electrochemical characterization. The nature and abundance of specific structure elements was correlated with the CO oxidation activity to obtain information on the nature of different active sites and their relative activity.
N.M. Marković et al., Surf. Sci. Rep. 45 (2002) 117.