The reactivity of selenite toward methyl viologen in mildly acidic aqueous solutions

Qi Han, Zhange Feng, Daniel Alberto Scherson

Research output: Contribution to journalArticle

Abstract

The chemical and electrochemical reactivity of selenite, SeO3 2−, toward methyl viologen, MV2+, has been examined in mildly acidic (pH 4) aqueous electrolytes. Solutions containing these two species heated at 60°C for ca. 2 hours, were found to yield both 1-methyl-[4,4′-bipyridine]-1-ium chloride and elemental Se as the main reaction products, as evidenced from information derived from mass spectrometric and spectroscopic techniques. Cyclic voltammetric measurements recorded in acetate buffer (pH 4) with a glassy carbon, GC, electrode bearing a self-assembled monolayer, SAM, of N-ethyl-N′-octadecyl-4,4′-bipyridinium (EOB), which had been exposed to a 100 mM SeO3 2− solution in aqueous acetate buffer (pH 4) for over 200 min and then rinsed with ultrapure water, displayed a significantly smaller redox peak ascribed to the reduction of the viologen moiety in the EOB SAM. This observation is consistent with the loss of the redox active species within the layer and supports the view that SeO3 2− can cleave the N-C bond in EOB leading to the release of the viologen group into the solution. Cyclic voltammetric experiments involving a freshly prepared EOB SAM on GC in 1 mM SeO3 2− in the same buffer yielded a large reduction current with an onset potential virtually identical to that associated with the reduction of the EOB SAM in SeO3 2−-free solutions. On this basis, the extraordinary shift in the onset of SeO3 2− reduction induced by the presence of MV2+ in the same electrolyte reported by Koshikumo et al. [Electrochemistry (Tokyo, Jpn.), 81(5), 350 (2013)], may be explained by invoking formation of MV2+ aggregates on the GC surface in amounts too small to be detected by conventional voltammetric techniques.

Original languageEnglish
Pages (from-to)H890-H895
JournalJournal of the Electrochemical Society
Volume164
Issue number13
DOIs
Publication statusPublished - 2017 Jan 1
Externally publishedYes

Fingerprint

Selenious Acid
Paraquat
Viologens
Buffers
Electrolytes
Acetates
Bearings (structural)
Glassy carbon
Self assembled monolayers
Electrochemistry
Reaction products
Chlorides
Electrodes
Water
Experiments
Oxidation-Reduction

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Surfaces, Coatings and Films
  • Electrochemistry
  • Materials Chemistry

Cite this

The reactivity of selenite toward methyl viologen in mildly acidic aqueous solutions. / Han, Qi; Feng, Zhange; Scherson, Daniel Alberto.

In: Journal of the Electrochemical Society, Vol. 164, No. 13, 01.01.2017, p. H890-H895.

Research output: Contribution to journalArticle

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