Journal Article

PreJuSER-8081

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Anomalous Helmholtz-Capacitance on Stepped Surfaces of Silver and Gold

Beltramo, G. L.FZJ* ; Giesen, M.FZJ* ; Ibach, H.FZJ*

2009
Elsevier New York, NY [u.a.]

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Please use a persistent id in citations: doi:10.1016/j.electacta.2009.02.087

Abstract: We have studied the capacitance of the solid/electrolyte interface on Ag(11n) and Au(11n) surfaces in KClO4 and HClO4 as function of the electrolyte concentration and the step density. We find that the inner layer capacitance (Helmholtz-capacitance) at the potential of (total) zero charge is dramatically reduced on stepped surfaces. Standard theories which describe the Helmholtz-capacitance by properties of the liquid, a hard wall boundary condition and the polarizability of the electron gas at the metal surface fail to describe this behavior. We propose that the different polarizability of water bonded to the surface need be taken into account and attribute the reduced capacitance at steps to the lower polarizability of water molecules bonded to step edges. (C) 2009 Elsevier Ltd. All rights reserved.

Keyword(s): J ; Cold (auto) ; Silver (auto) ; Stepped single crystals (auto) ; Helmholtz-capacitance (auto)

Note: We thank Karina Morgenstern, University Hannover, for a helpful exchange of ideas on the adsorption of water at steps and for making STM images available to us prior to publication. Inspiring discussions with Wolfgang Schmickler, University Ulm, are also gratefully acknowledged. Udo Linke has contributed significantly to this work by his careful and innovative preparation of the crystal surfaces. The work was partially supported by the Fond derChemischen Industrie and the Deutsche Forschungsgemeinschaft.

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Contributing Institute(s):

1. Grenz- und Oberflächen (IBN-3)
2. Jülich-Aachen Research Alliance - Fundamentals of Future Information Technology (JARA-FIT)
3. Biomechanik (IBN-4)

Research Program(s):

1. Grundlagen für zukünftige Informationstechnologien (P42)
2. Kondensierte Materie (P54)

Appears in the scientific report 2009

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