Density functional theory-based electrochemical models for the oxygen reduction reaction: Comparison of modeling approaches for electric field and solvent effects

Authors

  • Kuan-Yu Yeh,

    1. Department of Chemical Engineering, Pennsylvania State University, 104 Fenske Lab, University Park, Pennsylvania 16802
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  • Michael J. Janik

    Corresponding author
    1. Department of Chemical Engineering, Pennsylvania State University, 104 Fenske Lab, University Park, Pennsylvania 16802
    • Department of Chemical Engineering, Pennsylvania State University, 104 Fenske Lab, University Park, Pennsylvania 16802
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Abstract

A series of density functional theory (DFT) based electrochemical models are applied to systematically examine the effect of solvent, local electric field, and electrode potential on oxygen reduction reaction (ORR) kinetics. Specifically, the key elementary reaction steps of molecular oxygen dissociation, molecular oxygen protonation, and reduction of a hydroxyl adsorbate to water over the Pt(111) surface were considered. The local electric field has slight influence on reaction energetics at the vacuum interface. Solvent molecules stabilize surface adsorbates, assisting oxygen reduction. A collective solvation-potential coupled effect is identified by including long range solvent-solvent interactions in the DFT model. The dominant path of the ORR reaction varies with electrode potential and among the modeling approaches considered. The potential dependent reaction path determined from the solvated model qualitatively agrees with experiment ORR kinetics. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011

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