Berlin 2012 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 15: Heterogeneous catalysis I
O 15.7: Vortrag
Montag, 26. März 2012, 17:30–17:45, MA 042
The electrochemical promotion of ethylene oxidation at bimetallic Pt-Ag/YSZ catalyst — •Arafat Toghan1, Rosa Arrigo2, Axel Knop-Gericke2, Robert Schlögl2, and Ronald Imbihl1 — 1Institut für Physikalische Chemie und Elektrochemie, Universität Hannover, Callinstrasse 3-3a, D-30167 Hannover, Germany — 2Fritz-Haber-Insititut der Max-Planck Gesellschaft, Abteilung Anorganische Chemie, Faradayweg 4-6, D-14195 Berlin, Germany
The electrochemical promotion of the C2H4 + O2 reaction at bimetallic Pt/Ag catalyst interfaced to yttrium stabilized zirconia (YSZ) has been studied at high pressure (close to 1 mbar) using X-ray photoelectron spectroscopy (XPS) at BESSY as in situ method to identify the relevant surface species. Setting the working electrode at positive potential of 2V causes a relative rate increase in the CO2 production up to 120%; the electrocatalytic promotion effect (EPOC) is non-Faradaic (Lambda= 2.18). An EPOC effect is only observed at high p(C2H4)/p(O2) ratios when a carbonaceous CHx layers builds up inhibiting O2 adsorption. Only at low p(C2H4) the application of an electric potential causes a decrease in the carbon signal associated with a growth of the O1s signal at 529.3 eV [1-2]. The latter species can be assigned to an electrochemically generated oxygen spillover species at Ag sites. [1] A. Toghan, L. M. Rösken, R. Imbihl, ChemPhysChem 2010, 11, 1452-1459. [2] A. Toghan, L. M. Rösken, R. Imbihl, Phys. Chem. Chem. Phys. 2010, 12, 9811-9815.