Electrocatalytic Oxygen Reduction Reaction on Perovskite Oxides: Series versus Direct Pathway

Authors

  • Dr. Tiphaine Poux,

    1. Institut de Chimie et Procédés pour l'Energie l'Environnement et la Santé, UMR 7515 CNRS-University of Strasbourg, 25 rue Becquerel 67087 Strasbourg Cedex 2 (France), Fax: (+33) 03-68-85-27-61
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  • Dr. Antoine Bonnefont,

    1. Institut de Chimie de Strasbourg, UMR 7177 CNRS- University of Strasbourg, 4 rue Blaise Pascal, 67070 Strasbourg (France)
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  • Dr. Gwénaëlle Kéranguéven,

    1. Institut de Chimie et Procédés pour l'Energie l'Environnement et la Santé, UMR 7515 CNRS-University of Strasbourg, 25 rue Becquerel 67087 Strasbourg Cedex 2 (France), Fax: (+33) 03-68-85-27-61
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  • Prof. Galina A. Tsirlina,

    1. Faculty of Chemistry, Moscow State University, 119991 Leninskie Gory, Moscow (Russia)
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  • Prof. Elena R. Savinova

    Corresponding author
    1. Institut de Chimie et Procédés pour l'Energie l'Environnement et la Santé, UMR 7515 CNRS-University of Strasbourg, 25 rue Becquerel 67087 Strasbourg Cedex 2 (France), Fax: (+33) 03-68-85-27-61
    • Institut de Chimie et Procédés pour l'Energie l'Environnement et la Santé, UMR 7515 CNRS-University of Strasbourg, 25 rue Becquerel 67087 Strasbourg Cedex 2 (France), Fax: (+33) 03-68-85-27-61===

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Abstract

The mechanism of the oxygen reduction reaction (ORR) on LaCoO3 and La0.8Sr0.2MnO3 perovskite oxides is studied in 1 M NaOH by using the rotating ring disc electrode (RRDE) method. By combining experimental studies with kinetic modeling, it was demonstrated that on perovskite, as well as on perovskite/carbon electrodes, the ORR follows a series pathway through the intermediate formation of hydrogen peroxide. The escape of this intermediate from the electrode strongly depends on: 1) The loading of perovskite; high loadings lead to an overall 4 e oxygen reduction due to efficient hydrogen peroxide re-adsorption on the active sites and its further reduction. 2) The addition of carbon to the catalytic layer, which affects both the utilization of the perovskite surface and the production of hydrogen peroxide. 3) The type of oxide; La0.8Sr0.2MnO3 displays higher (compared to LaCoO3) activity in the reduction of oxygen to hydrogen peroxide and in the reduction/oxidation of the latter.

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