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Sequential Activation and Oscillations of Globally Coupled Microelectrodes during a Bistable Reaction

Authors

  • Dr. D. Alfonso Crespo-Yapur,

    1. Institut de Chimie et Procédés pour l'Energie l'Environnement et la Santé, UMR 7515 of CNRS-Université de Strasbourg-ECPM, 25 rue Becquerel, 67087 Strasbourg (France)
    2. Physik-Department, Technische Universität München, James-Franck-Str. 1, 85748 Garching (Germany)
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  • Dr. Antoine Bonnefont,

    Corresponding author
    1. Institut de Chimie de Strasbourg, UMR 7177, CNRS-Université de Strasbourg, 4 rue Blaise Pascal, 67000 Strasbourg (France), Tel.: 0033(0)3 68 85 14 18, Fax: 0033(0)3 68 85 17 31
    • Institut de Chimie de Strasbourg, UMR 7177, CNRS-Université de Strasbourg, 4 rue Blaise Pascal, 67000 Strasbourg (France), Tel.: 0033(0)3 68 85 14 18, Fax: 0033(0)3 68 85 17 31===

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  • Prof. Rolf Schuster,

    1. Institute of Physical Chemistry, Karlsruhe Institute of Technology, Kaiserstr. 12, 76131 Karlsruhe (Germany)
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  • Prof. Katharina Krischer,

    1. Physik-Department, Technische Universität München, James-Franck-Str. 1, 85748 Garching (Germany)
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  • Prof. Elena R. Savinova

    1. Institut de Chimie et Procédés pour l'Energie l'Environnement et la Santé, UMR 7515 of CNRS-Université de Strasbourg-ECPM, 25 rue Becquerel, 67087 Strasbourg (France)
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Abstract

The cooperative behavior of globally coupled Pt microelectrodes during the bistable CO bulk electrooxidation is explored as a function of the concentration of the H2SO4 supporting electrolyte and the capacitance of the electrochemical system. By measuring the individual currents flowing through each of the microelectrodes, different kinds of cooperative behavior can be evidenced. In addition to the sequential activation of the microelectrodes arising when the applied reaction current value is linearly increased, the emergence of two types of spontaneous potential oscillations are observed in dilute sulfuric acid: 1) low-amplitude potential oscillations, resulting from the coherent synchronization of noisy microelectrodes, and 2) large-amplitude passivation–activation potential oscillations, which are only observed at high electrode capacitance. These cooperative behaviors are discussed with the help of a mean-field model for CO oxidation.

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