Dresden 2017 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 72: Oxide and Insulator Surfaces: Adsorption I

O 72.6: Vortrag

Mittwoch, 22. März 2017, 11:45–12:00, WIL C107

In-situ Spectro-electrochemical Infrared Investigations at Atomically-Defined Pt/Co3O4(111) Model Catalysts — •Firas Faisal, Olaf Brummel, Manon Bertram, Corinna Stumm, and Jörg Libuda — Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen

We prepared in ultra-high-vacuum (UHV) highly ordered thin films of Co3O4(111) on Ir(100) and deposited Pt nanoparticles to obtain model catalysts for electrochemical investigations. The model systems were directly transferred from UHV into the spectro-electrochemical cell and back without contact to ambient conditions. As a probe reaction we used the electrooxidation of CO, monitored by electrochemical infrared-reflection absorption spectroscopy (EC-IRRAS) in thin film configuration. All samples were characterized by low-energy electron diffraction (LEED) and Auger electron spectroscopy (AES) before and after the electrochemical treatment. We identified a pH and potential window in which the Co3O4(111) film is perfectly stable in the electrochemical environment. This allowed us to explore potential-dependent differences in the CO site occupation on the UHV-prepared supported model catalyst in comparison to a Pt(111) reference sample prepared by flame annealing. Specifically, we observed strong suppression of bridging CO on Pt facets and identify additional strongly bound CO at low coordinated Pt atoms which persists at the electrode up to high electrode potentials.