Regensburg 2013 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 58: Poster Session III (Solid-liquid interfaces; Scanning probe and other methods; Electronic structure theory; Spin-orbit interaction)

O 58.9: Poster

Mittwoch, 13. März 2013, 18:15–21:45, Poster B1

Work function change introduced by water on a halogen covered Pt(111) surface — •Florian Gossenberger and Axel Groß — Institute of Theoretical Chemistry, Ulm University, D-89069 Ulm/Germany

Anion adsorption on metal electrodes plays an important role in electrochemistry. Still, the knowledge about the microscopic structure of the interface between anion-covered electrodes and the electrolyte is still limited. We have used periodic density functional theory calculations to address the adsorption of halogen atoms (F, Cl, Br, I) on Pt(111). Typically, one expects that the adsorption of electronegative adsorbates will increase the work function. Interestingly enough, we find that the adsorption of halogens on a clean Pt(111) may lead to a significant decrease in the work function. According to our calculations, this behavior is due to a reduction in the surface dipole moment which itself depends on the charge distribution around the adsorbed halogen atoms.

Furthermore, we have studied the interaction of the adsorbed halogen atoms with single water molecules and whole water layers. We will in particular discuss the influence of the water molecules on the halogen-induced work function change of Pt(111).