Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 17: Solid-liquid interfaces: Reactions and electrochemisty I (joint session O/CPP)
O 17.3: Vortrag
Montag, 12. März 2018, 15:30–15:45, MA 144
Correlation of Surface Site Formation to Nano-Island Growth in the Electrochemical Roughening of Pt(111) — Leon Jacobse1, Yi-Fan Huang1, Marc Koper1, and •Marcel Rost2 — 1Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands — 2Huygens-Kamerlingh Onnes Laboratory, Leiden University, Leiden, The Netherlands
Platinum plays a central role in a wide variety of electrochemical devices. Electrode degradation, especially under oxidizing conditions, forms an important barrier for the widespread of applications. Although it is known that repeated oxidation and reduction of platinum electrodes results in irreversible surface structure changes, over thirty years of research did not yet yield to a conclusive description of this process on the atomic level; even not for well-defined single crystal surfaces.
Using a special EC-STM, which is capable of measuring the electrochemical signals simultaneously during imaging in operando, we directly correlate, for the first time, the evolution of the hydrogen adsorption peaks on Pt(111) to the observed roughening of the surface. In the later stages, we find a strong correlation between the evolution of the roughness and the absorption peaks clearly indicating that each created step contributes equally strong to the adsorption signal as well as to the roughness. However, and fully surprising, in the early stage step edges are created that seem to be chemically "dead".