Electrochemical behaviour of aqueous SO2 at polycrystalline gold electrodes in acidic media: a voltammetric and in situ vibrational study: Part 1. Reduction of SO2: deposition of monomeric and polymeric sulphur

C. Quijada, F.J. Huerta, E. Morallon, J.L. Vazquez, L.E.A. Berlouis

Research output: Contribution to journalArticlepeer-review

31 Citations (Scopus)

Abstract

The electro-reduction of SO2 has been monitored by using cyclic voltammetry, FT-IR spectroscopy and SER spectroscopy. Prior to the bulk reduction, SO2 is reduced to yield a monomeric sulphur adlayer at a maximum coverage of about 0.25. The sulphur adlayer undergoes a reversible redox surface process at E<0.0 V (RHE), which implies a change in the frequency of the Au---S stretching mode from 270 to 300/310 cm−1. In the potential region encompassing the bulk reduction voltammetric peak, infrared spectra display a band at 2585 cm−1 attributable to a S---H vibration from a soluble species. Accordingly, H2S or H2Sx were proposed as tentative bulk reduction products. In positive sweeps a broad anodic wave develops between 0.2 and 0.6 V that leaves polymeric sulphur species adsorbed at multilayer level, with a S---S stretching mode at 460 cm−1 and a S---S---S bending vibration at 218 cm−1. Multilayer sulphur can be removed reductively under a sharp cathodic peak. According to literature of the S(-II)/Au system, removal proceeds to yield soluble S(-II) species, via intermediate polysulphides.
Original languageEnglish
Pages (from-to)1847-1862
Number of pages15
JournalElectrochimica Acta
Volume45
Issue number11
DOIs
Publication statusPublished - 1 Feb 2000

Keywords

  • sulphur dioxide
  • sulphur adsorption
  • gold electrode
  • cyclic voltammetry
  • SER spectroscopy
  • FT-IR spectroscopy
  • electro-reduction

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