Regensburg 2010 – scientific programme

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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 59.105: Poster

Wednesday, March 24, 2010, 17:45–20:30, Poster B1

DFT studies on the hydrogen adsorption on Pt(111) and Pt(111)-hydride surfaces — •Fedir Strygunov and Timo Jacob — Universität Ulm, Albert-Einstein-Allee 47, D-89069 Ulm, Germany

The catalytic reaction of hydrogen on Pt electrodes is one of the simplest, most fundamental and important reactions in electrochemistry. However, despite the apparent simplicity of the hydrogen oxidation and evolution reactions (HOR/HER) and a large numbers of studies, there is still no consensus about adsorption states of hydrogen on Pt electrodes.

Using periodic density functional theory in combination with the extended ab initio atomistic thermodynamics approach [1, 2] the structure and stability of clean Pt(111) and Pt(111)-hydride electrodes have been investigated. We find that at low coverages hydrogen prefers surface positions, but above 2 ML hydrogen also occupies subsurface tetrahedral positions, leading to the formation of a surface hydride. The electrochemical surface phase diagram showed that such a surface hydride might be stabilized with negative electrode potentials. On the basis of the most relevant surface hydride structures, further studies will aim on the electrocatalytic hydrogen reactions.

[1] M. Scheffler, J. Dabrowski, Phil. Mag., A 58, 107 (1988).

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