Microelectrode Voltammetry of Dioxygen Reduction in a Phosphonium Cation-Based Room-Temperature Ionic Liquid: Quantitative Studies

Peilin Li, Edward O. Barnes, Christopher Hardacre, Richard G. Compton*

*Corresponding author for this work

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

Microelectrode voltammetry is used to study the electrochemical reduction of dioxygen, O-2, in the room-temperature ionic liquid trihexyl(tetradecyl)phosphonium trifluorotris(pentafluoroethyl)phosphate [P6,6,6,14][FAP]. The nature of the unusual voltammetric waves is quantitatively modeled via digital simulation with the aim of clarifying apparent inconsistencies in the literature. The reduction is shown to proceed via a two-electron reaction and involve the likely capture of a proton from the solvent system. The oxidative voltammetric signals seen at fast scan rates are interpreted as resulting from the reoxidation of HO2 center dot. In the presence of large amounts of dissolved carbon dioxide the reductive currents decrease by a factor of ca. two, consistent with the trapping of the superoxide radical, O-2(center dot), intermediate in the two-electron reduction process.

Original languageEnglish
Pages (from-to)2716-2726
Number of pages11
JournalJournal of Physical Chemistry C
Volume119
Issue number5
Early online date08 Jan 2015
DOIs
Publication statusPublished - 2015

Keywords

  • GOLD MICRODISK ELECTRODES
  • CARBON-DIOXIDE
  • SUPEROXIDE ION
  • ELECTROGENERATED SUPEROXIDE
  • ELECTROCHEMICAL REDUCTION
  • GAS SENSORS
  • DIFFUSION-COEFFICIENTS
  • APROTIC-SOLVENTS
  • CO2 REDUCTION
  • STEADY-STATE

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