Dresden 2014 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 62: Posters: Surface Reactions and Dynamics, Nanostructures
O 62.4: Poster
Mittwoch, 2. April 2014, 17:30–21:00, P1
Near ambient pressure XPS investigation of the oxidation and the CO oxidation on Pt(111) — •Mathias Grabau1, Sandra Krick Calderón1, László Óvári2, Hans-Peter Steinrück1, and Christian Papp1 — 1Physikalische Chemie II, University of Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen, Germany — 2MTA-SZTE Reaction Kinetics and Surface Chemistry Research Group, H-6720 Szeged, Rerrich Béla tér 1, Hungary
The oxidation of Pt(111) at oxygen pressures up to 1 mbar was followed in situ using (NAP)-XPS at temperatures between 300 and 700 K. The oxidation was found to proceed remarkably at temperatures of 300 and 500 K (oxygen coverage of 1.6 ML after 6 h at 300 K). The analysis of the data revealed varying saturation coverages found in situ, indicating a sensitive pressure- and temperature-dependent system. As a follow-up, the oxidation of CO by molecular oxygen on Pt(111) was investigated in the temperature range between 500 and 900 K using different reactant mixtures in continuous flow mode. Considerable reaction was observed at temperatures above 650 K under oxidizing conditions. Reaction onset at lower oxygen ratios was found for higher temperatures. Oxide formation under reaction conditions (T ≥ 650 K) was observed to lead to a lower catalyst activity up to complete inhibition of the CO oxidation reaction.