Dresden 2009 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 39: Metal substrates: Solid-liquid interfaces

O 39.3: Vortrag

Mittwoch, 25. März 2009, 15:30–15:45, SCH A315

Theoretical Studies on the Inner Potential Drop in Pt/Electrolyte-Interfaces — •Jochen Bandlow, Josef Anton, and Timo Jacob — Institut für Elektrochemie, Universität Ulm, 89081 Ulm

Understanding the processes occuring at solid/liquid interfaces is of great importance not only for basic electrochemistry, but also for various applications such as fuel cells. However, these interfaces (i.e., the so-called electric double-layers) are rather complex involving different aspects as surface dipoles, a potential drop, specific and non-specific adsorption, or modified surface structures. Since many experimental techniques that are well-established in surface science are not applicable for systems under "wet" conditions, theoretical modeling might help understanding the double-layer on the microscopic level.

In order to evaluate the drop of the electrostatic potential within the electric double-layer first we performed molecular dyanamics studies on pure water under different pressure and temperature conditions. We found that many commonly used interaction potentials reported in literature are only valid for a rather limited part of the phase-space. Afterwards, we studied the molecular structure of charged platinum electrodes in contact with an aqueous solution containing various concentrations of NaCl. This allowed us to evaluate the peak and also the averaged potential distribution.