Regensburg 2010 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 59: Poster Session II (Nanostructures at surfaces: Dots, particles, clusters; Nanostructures at surfaces: arrays; Nanostructures at surfaces: Wires, tubes; Nanostructures at surfaces: Other; Plasmonics and nanooptics; Metal substrates: Epitaxy and growth; Metal substrates: Solid-liquid interfaces; Metal substrates: Adsoprtion of organic / bio molecules; Metal substrates: Adsoprtion of inorganic molecules; Metal substrates: Adsoprtion of O and/or H; Metal substrates: Clean surfaces; Density functional theory and beyond for real materials)
O 59.107: Poster
Mittwoch, 24. März 2010, 17:45–20:30, Poster B1
Surface oxidation of planar and stepped Pt(111) surfaces studied by DFT — •Jochen Bandlow and Timo Jacob — Universität Ulm, Albert-Einstein-Allee 44, 89069 Ulm, Germany
The surface oxidation of Pt(111) seems to be a rather basic and quite simple reaction but nevertheless plays an important role for a wide range of catalytic reactions in gas-phase surface science and electrochemistry. Despite the fact that many experimental studies are focused on single crystal systems with (almost) perfect surfaces, realistic catalysts always contain stepedges, kinks, vacancies and other imperfections on the surface. Especially these lower coordinated sites are believed to play a decisive role for surface reactions and the catalytic performance.
In the present work we investigated the adsorption of oxygen on perfect and stepped Pt(111) using density functional theory and the extended ab initio thermodynamics approach. By comparing the (p,T) phase diagram for the system in contact with a gaseous O2 atmosphere with the corresponding electrochemical (p,T,φ) phase diagram, characteristics of the surface morphology under specific conditions were evaluated. It turned out that the model of a pure and perfect Pt(111) surface, which is often used to study this reaction, is clearly incomplete.