Electrochemical oxidation of H2 and CO in a H2-H2O-CO-CO2 system at the interface of a Ni-YSZ cermet electrode and YSZ electrolyte

Yoshio Matsuzaki, Isamu Yasuda

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215 Citations (Scopus)

Abstract

The electrochemical oxidation of H2 and CO in a H2-H2O-CO-CO2 system at the interface of a porous Ni-yttria stabilized zirconia (YSZ) cermet electrode and YSZ electrolyte has been studied using complex-impedance spectroscopy and direct-current polarization measurements of 1023 and 1273 K under a constant oxygen partial pressure. The polarization resistance increased when the CO concentration ratio, pCO/[pH(2) + pCO], exceeded 0.2 and 0.5 at 1023 and 1273 K, respectively. The electrochemical oxidation rate of H2 was 1.9-2.3 times and 2.3-3.1 times higher than that of CO at 1023 and 1273 K, respectively, and the water-gas shift reaction was found to be much faster than the electrode reaction at both temperatures. An equivalent-circuit analysis of the complex-impedance spectra suggested that the lower electrochemical oxidation rate of CO (compared to H2) was caused mainly by the larger diffusion resistance of CO than H2 on the electrode surface at 1023 K, and by both the larger surface diffusion resistance and charge-transfer resistance at 1273 K.

Original languageEnglish
Pages (from-to)1630-1635
Number of pages6
JournalJournal of the Electrochemical Society
Volume147
Issue number5
DOIs
Publication statusPublished - May 2000
Externally publishedYes

All Science Journal Classification (ASJC) codes

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

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