Electrochemical promotion of a metal catalyst supported on a mixed-ionic conductor

D. Poulidi*, I. S. Metcalfe

*Corresponding author for this work

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

It has been found that the catalytic activity and selectivity of a metal film deposited on a solid electrolyte could be enhanced dramatically and in a reversible way by applying an electrical current or potential between the metal catalyst and the counter electrode (also deposited on the electrolyte). This phenomenon is know as NEMCA [S. Bebelis, C.G. Vayenas, Journal of Catalysis, 118 (1989) 125-146.] or electrochemical promotion (EP) [J. Prichard, Nature, 343 (1990) 592.] of catalysis. Yttria-doped barium zirconate, BaZr0.9Y0.1O3 - α (BZY), a known proton conductor, has been used in this study. It has been reported that proton conducting perovskites can, under the appropriate conditions, act also as oxide ion conductors. In mixed conducting systems the mechanism of conduction depends upon the gas atmosphere that to which the material is exposed. Therefore, the use of a mixed ionic (oxide ion and proton) conducting membrane as a support for a platinum catalyst may facilitate the tuning of the promotional behaviour of the catalyst by allowing the control of the conduction mechanism of the electrolyte. The conductivity of BZY under different atmospheres was measured and the presence of oxide ion conduction under the appropriate conditions was confirmed. Moreover, kinetic experiments on ethylene oxidation corroborated the findings from the conductivity measurements showing that the use of a mixed ionic conductor allows for the tuning of the reaction rate.

Original languageEnglish
Pages (from-to)2211-2215
Number of pages5
JournalSolid State Ionics
Volume177
Issue number26-32 SPEC. ISS.
DOIs
Publication statusPublished - 31 Oct 2006

Keywords

  • BaZrYO
  • Electrochemical impedance
  • Electrochemical promotion
  • Electrode-support interactions
  • Mixed-ionic conductivity

ASJC Scopus subject areas

  • Electrochemistry
  • Physical and Theoretical Chemistry
  • Energy Engineering and Power Technology
  • Materials Chemistry
  • Condensed Matter Physics

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