Electrolytic oxidation of Ce(III) in nitric acid and sulfuric acid media using a flow type cell

Y. Wei, B. Fang, T. Arai, M. Kumagai

Research output: Contribution to journalArticle

67 Citations (Scopus)

Abstract

The electrochemical oxidation behavior of Ce(III) in nitric acid and sulfuric acid media with various concentrations and compositions were investigated by cyclic voltammetry (CV) and potentiostatic electrolysis. In nitric acid media the peak potential separation for the redox reactions of the Ce(III)/Ce(IV) couple shifted to base side with the increasing concentration of nitric acid from 1 to 6 M. The kinetics of the Ce(III)/Ce(IV) couple is rapid in high concentration nitric acid. The formal potential is independent of both proton and nitrate concentrations while the standard rate constant increases with added protons but is independent of nitrate concentration. Constant-potential electrolysis also shows that a high proton concentration is electrochemically favorable for the electron transfer of the Ce(III)/Ce(IV) couple and for a high Ce(IV) yield in nitric acid media. The current efficiency was ca. 75% for the oxidation process of Ce(III) at 298 K. A Ce(IV) yield of ca. 80% was achieved for the electrolysis of 100 mM Ce(III) in 6 M HNO3 solution. In sulfuric acid media the peak potential separation for the redox reactions of the Ce(III)/Ce(IV) couple shifted to noble side with rising concentration of sulfuric acid from 0.1 to 2 M and then shifted to base side with further increase in the concentration. A Ce(IV) yield of ca. 95% was achieved for the potentiostatic electrolysis of 100 mM Ce(III) in 3 M H 2SO4 solution.

Original languageEnglish
Pages (from-to)561-566
Number of pages6
JournalJournal of Applied Electrochemistry
Volume35
Issue number6
DOIs
Publication statusPublished - 2005 Jun 1
Externally publishedYes

Keywords

  • Carbon electrode
  • Cerium
  • Electrochemical oxidation
  • Electrolysis
  • Flow type electrolytic cell
  • Nitric acid
  • Sulfuric acid

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Electrochemistry
  • Materials Chemistry

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