Electrochemical promotion of catalysis using solid-state proton-conducting membranes

D. Poulidi, M. A. Castillo-del-Rio, R. Salar, A. Thursfield, I. S. Metcalfe*

*Corresponding author for this work

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

A solid-state electrochemical reactor with ceramic proton-conducting membrane has been used to study the effect of electrochemically induced hydrogen spillover on the catalytic activity of platinum during ethylene oxidation. Suitable proton-conducting electrolyte membranes (Gd-doped BaPrO 3 (BPG) and Y-doped BaZrO3 (BZY)) were fabricated. These materials were chosen because of their protonic conductivity in the operational temperature region of the reaction (400-700 °C). The BZY-based electrochemical cell was used to investigate the open-circuit voltage (OCV) dependence on H2 partial pressure with comparison being made to the theoretical OCV as predicted by the Nernst equation. Furthermore, the BZY pellets were used to study the effect of proton transfer of the catalytic activity of platinum during ethylene oxidation. The reaction was found to exhibit electrochemical promotion at 400 °C and to be electrophilic in nature, i.e. proton addition to the platinum surface resulted in an increase in reaction rate. At higher temperatures, the rate was not affected, within experimental error, by proton addition or removal. Under similar conditions, AC impedance showed that there was a large overall cell resistance at 400 °C with significantly decreased resistance at higher temperatures. It is possible that there could be a relationship between large cell resistances and the onset of electrochemical promotion in this system but there is, as yet, no conclusive evidence for this.

Original languageEnglish
Pages (from-to)305-311
Number of pages7
JournalSolid State Ionics
Volume162-163
DOIs
Publication statusPublished - Sep 2003

Keywords

  • BaPrGdO
  • BaZrYO
  • Electrochemical promotion
  • Ethylene oxidation
  • Proton conductors
  • Solid-state reaction

ASJC Scopus subject areas

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

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