In-situ radiotracer studies of sorption processes in solutions containing (bi)sulfite ions - I. Polycrystalline gold

K. Varga, P. Baradlai, A. Vértes

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

In this work, we report some new findings obtained by the in-situ radiotracer and voltammetric studies of the time, potential and pH dependence of sorption processes on polycrystalline gold in ClO4- supporting electrolytes containing aqueous SO2. Besides this, adsorption behaviour of species created from aqueous SO2 (HSO3-/SO32- ions and/or molecular SO2 as well as their oxidation and reduction products) is compared with that of HSO4-/SO42- ions in order to get a deeper insight into the nature and sorption properties of oxidation products. Both the oxidation and reduction of aqueous SO2 occur on a polycrystalline gold in acid solutions between the onset of hydrogen and oxygen evolution. At higher pH values (3.5 and 6.5) the onset of the oxidation processes shifts towards more positive potentials and the electroreduction commences at less positive potential values. It is probable that a poisoning effect owing to oxidized adspecies rather than the electrocatalytic behaviour of adsorbed reduction products prevail over the electrooxidation phenomena. Both HSO4-/SO42- and S2O62- are presumably formed (and adsorbed) on gold upon electrooxidation of aqueous SO2. The apparent inhibition of the electrooxidation processes in acid solutions may most likely be due to the formation of some surface complexes consisting of oxidized adspecies and "strongly bonded" molecular SO2.

Original languageEnglish
Pages (from-to)1143-1155
Number of pages13
JournalElectrochimica Acta
Volume42
Issue number7
DOIs
Publication statusPublished - Jan 1 1997

Keywords

  • Adsorption of HSO/SO and HSO/SO ions
  • Cyclic voltammetry
  • In-situ radiotracer method
  • Polycrystalline gold
  • Surface reactions

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Electrochemistry

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