Regensburg 2013 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 8: Surface Chemical Reactions and Heterogeneous Catalysis I
O 8.10: Vortrag
Montag, 11. März 2013, 12:45–13:00, H33
Dissociative adsorption of water on stepped metal surfaces — •Davide Donadio1, Rengin Pekoez1, Svenja Woerner1, Luca Ghiringhelli2, and Luigi Delle Site3 — 1Max Planck Institute for Polymer Research, Mainz, Germany — 2Fritz Haber Institute, Berlin, Germany — 3Freie Universität Berlin, Germany
Water-metal interfaces play a key role in many chemical processes, from catalysis to corrosion and photoelectrochemistry. Whereas water adlayers on atomically flat transition metal surfaces have been investigated in depth, little is known about water on stepped surfaces [1].
Using first-principles simulations we study the adsorption of water on stepped Pt, Pd, Rh, Ni and Ir surfaces. We find that the chemistry of water at steps is in general different and cannot be predicted based on the acquired knowledge on flat surfaces. For example at Pt steps, in contrast with flat surfaces, water molecules dissociate forming mixed hydroxyl/water structures, through an autocatalytic mechanism promoted by hydrogen bonding [2]. Similar effects are analyzed systematically for several metals, and general trends are devised. Together with the attitude of water chains on metal steps to transfer protons via thermally activated hopping, these findings candidate these systems as viable proton wires.
[1] A. Hodgson and S. Haq, Surf. Sci. Rep. 64, 381 (2009).
[2] D. Donadio, L. M. Ghiringhelli and L. Delle Site, J. Am. Chem. Soc. 134, 19217 (2012)