On the catalytic and degradative role of oxygen-containing groups on carbon electrode in non-aqueous ORR

Alina I. Inozemtseva, Elmar Yu Kataev, Alexander S. Frolov, Matteo Amati, Luca Gregoratti, Klára Beranová, Virginia Pérez Dieste, Carlos Escudero, Alexander Fedorov, Artem V. Tarasov, Dmitry Yu Usachov, Denis V. Vyalikh, Yang Shao-Horn, Daniil M. Itkis, Lada V. Yashina

Research output: Contribution to journalArticlepeer-review

Abstract

Oxygen reduction reaction (ORR) is a crucial process that drives the operation of several energy storage devices. ORR can proceed on the neat carbon surface in the absence of a catalyst, and its electrochemical activity is determined by its microstructure and chemical composition. Oxygen functional groups unavoidably existing on the carbon surface can serve as adsorption sites for ORR intermediates; the presence of some oxygen functionalities gives rise to an increase in the density of electronic states (DOS) at the Fermi level (FL). Both factors should have a positive impact on the electron transfer rate that was demonstrated for ORR in aqueous media. To study the O-groups effect on the aprotic ORR, which is now of interest due to the extensive development of aprotic metal-air batteries, we use model oxidized carbon electrodes (HOPG and single-layer graphene). We demonstrate that oxygen functionalities (epoxy, carbonyl, and lactone) do not affect the rate of one-electron oxygen reduction in aprotic media in the absence of metal cations since their introduction practically does not increase DOS at FL. However, in Li+-containing electrolytes, oxygen groups enhance both the rate of second electron transfer and carbon degradation due to its oxidation by LiO2 yielding carbonate species.

Original languageEnglish
Pages (from-to)632-641
Number of pages10
JournalCarbon
Volume176
DOIs
StatePublished - May 2021

Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)

Keywords

  • Graphene
  • Li–O2 batteries
  • Oxygen functionalities
  • Oxygen reduction

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