Modeling of oxygen reduction reaction in porous carbon materials in alkaline medium. Effect of microporosity

Atsushi Gabe, Ramiro Ruiz-Rosas, Carolina González-Gaitán, Emilia Morallón, Diego Cazorla-Amorós

    Research output: Contribution to journalArticlepeer-review

    22 Citations (Scopus)

    Abstract

    The role of porosity, and more specifically, microporosity, in the performance of carbon materials as Oxygen Reduction Reaction (ORR) catalysts in alkaline medium still has to be clarified. For this purpose, a highly microporous KOH-activated carbon and a microporous char have been prepared and their ORR performance in alkaline media were compared to that of two commercial carbon blacks with low and high surface areas, respectively. Interestingly, all carbon materials show a two-wave electrocatalytic process, where the limiting current and the number of electron transferred increase when going to more negative potentials. The limiting current and onset potential of the second wave is positively related to the amount of microporosity, and H2O2 electrochemical reduction tests have confirmed that the second wave could be related to the catalytic activity towards this reaction. In accordance to these findings, a model is developed that takes into account narrow and wide micropores in both charge transfer reactions and the mass transfer rate of O2 and H2O2. This model successfully reproduces the experimental electrochemical response during ORR of the analyzed porous carbon materials and suggests the important role of narrow micropores in H2O2 reduction.

    Original languageEnglish
    Pages (from-to)451-464
    Number of pages14
    JournalJournal of Power Sources
    Volume412
    DOIs
    Publication statusPublished - 2019 Feb 1

    Keywords

    • Charge transfer reaction
    • Hydrogen peroxide reduction
    • Mass transfer rate
    • Microporosity
    • ORR mathematical modeling
    • Oxygen reduction reaction

    ASJC Scopus subject areas

    • Renewable Energy, Sustainability and the Environment
    • Energy Engineering and Power Technology
    • Physical and Theoretical Chemistry
    • Electrical and Electronic Engineering

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