Berlin 2008 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 68: Metal Substrates: Solid-Liquid Interfaces

O 68.5: Vortrag

Donnerstag, 28. Februar 2008, 14:15–14:30, MA 043

A new approach to obtain electrochemical E/pH diagrams derived from the viewpoint of semiconductor defects — •Mira Todorova and Jörg Neugebauer — Max-Planck Institut für Eisenforshung, Düsseldorf

We present a novel approach for obtaining Pourbaix diagrams, which depict possible thermodynamically stable phases of an aqueous electrochemical system under given environmental conditions as a function of potential and pH. Such diagrams play a crucial role in corrosion science and various areas of chemistry.

Being similar to the approach used in defect chemistry [1] the new method is safely based on the formation energy of ions in the host matrix. Within the new approach the electrode potential and the pH-scale can be easily understood. We obtain an astonishingly good agreement with the standard electrochemical potential series. The construction of E/pH diagrams for any given environmental conditions and without a priory assumptions about ion concentrations is possible and will be demonstrated by the example of zinc and iron.

[1] C.G. Van de Walle and J. Neugebauer, J. Appl. Phys. 95, 3851 (2004).