Regensburg 2016 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 60: Chemistry at Solid/Liquid Interfaces
O 60.11: Vortrag
Mittwoch, 9. März 2016, 17:45–18:00, S052
Electro-oxidation of methanol and CO on UHV prepared Pt modified Ru(0001) model electrodes — •Jens Klein, Fabian Argast, Albert K. Engstfeld, Sylvain Brimaud, and R. Jürgen Behm — Ulm University, Institute of Surface Chemistry and Catalysis, 89069 Ulm, Germany
Bimetallic platinum-ruthenium catalysts are the state-of-the-art anode electrode materials for direct methanol fuel cells, since they show a much higher activity towards both the methanol (MeOH) oxidation and the CO oxidation compared to the standard anode catalyst Pt. The higher activity has been ascribed to adjacent bimetallic PtRu-sites (bifunctional mechanism). The actual structure of the active sites remained, however, unclear.
For a more detailed understanding of the structure–activity relationship of this system, we investigated these reactions on structurally well-defined nanostructured bimetallic Pt modified Ru(0001) surfaces in a combined ultrahigh vacuum (UHV) – electrochemical (EC) flow cell setup. Different Pt- and PtRu-nanostructures with varying Pt coverage and varying number of adjacent PtRu-sites were prepared by physical vapor deposition of Pt on Ru(0001) at different temperatures and then characterized by scanning tunneling microscopy (STM).
After structural analysis, the model electrodes were transferred to an EC flow cell attached to the UHV system, to investigate their electrocatalytic activity during MeOH oxidation and bulk CO oxidation in H2SO4 by cyclic voltammetry. The electrocatalytic activity was correlated with the abundance of key PtRu nanostructures on the surfaces.