Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 61: Focus Session: Nanoscale Insights into Interfacial Electrochemistry I
O 61.3: Vortrag
Mittwoch, 14. März 2018, 11:30–11:45, HE 101
Molecular dynamics study of the Mg(0001)/H2O interface in an ab initio electrochemical cell — •Sudarsan Surendralal1, Mira Todorova1, Michael W. Finnis2, and Jörg Neugebauer1 — 1Department of Computational Materials Design, Max-Planck-Institut für Eisenforschung GmbH., Düsseldorf, Germany — 2Department of Materials, Imperial College London, United Kingdom
Ab-initio modelling using density functional theory (DFT) provides important insight into the understanding of reactions at electrochemical interfaces. However, there is no commonly used method to tune the electrode potential in these simulations due to constraints imposed by the periodic boundary conditions common to many DFT codes. This is a major challenge for computational electrochemistry since it hampers observation of reactions under conditions of an applied potential. Utilizing semiconductor concepts, we have designed an approach to realize a potentiostat in standard periodic boundary DFT codes. Our approach allows the control of the electrode potential of the system by controlling the magnitude of charge transfer between two electrodes. Using this method, we study the Mg(0001)/H2O interface under anodic polarisation conditions. The high corrosion rate under these conditions is a severe technological challenge and has thus been extensively studied. The atomistic mechanisms, however, could so far not be identified. Using the new approach, we are able to observe dissociation events, proton transfer as well as H2 evolution and to identify a novel and hitherto not considered reaction mechanism.