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O: Fachverband Oberflächenphysik

O 12: Metal substrates: Adsorption of O / H and inorganic molecules I

O 12.7: Vortrag

Montag, 14. März 2011, 16:30–16:45, WIL A317

Surface oxidation of planar and stepped Pt(111) surfaces studied by DFT — •Jochen Bandlow, Payam Kaghazchi, and Timo Jacob — Abteilung Elektrochemie, Universität Ulm, Germany

The surface oxidation of Pt(111) 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 step edges, 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.[1] By comparing the (p,T) phase diagram for the system in contact with a gaseous O₂ atmosphere with the corresponding electrochemical (a,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.

[1] T. Jacob, J. Electroanal. Chem., 607, 158 (2007).