Electrical properties and flux performance of composite ceramic hydrogen separation membranes

J.S. Fish, Sandrine Ricote, R. O'Hayre, Nikolaos Bonanos

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

The electrical properties and hydrogen permeation flux behavior of the all-ceramic protonic/electronic conductor composite BaCe0.2Zr0.7Y0.1O3-δ/Sr0.95Ti0.9Nb0.1O3-δ (BCZY27/STN95: BS27) are evaluated. Conductivity and hydrogen permeability are examined as a function of phase volume ratios. Total conductivities of 0.01-0.06 S cm-1 are obtained in moist (+1% H2O) H2/inert gas from 600-800 °C for 50 volume% STN95. With increasing STN95 content (60 and 70 volume%), conductivity increases by 5-10 times, but displays a semiconductor-type dependence, even at 70 volume% STN95. The conductivity is modeled with an effective medium approach incorporating a term for the heterojunctions between the two phases. Hydrogen fluxes of 0.004-0.008 μmol cm-2 s-1 are obtained for a 50 volume% STN95 membrane sample (1 mm thickness) at 600-800 °C using dry argon as a sweep gas. Upon adding palladium layers as catalysts more than a five-fold increase is observed in the hydrogen flux, 0.025-0.026 μmol cm-2 s-1, over the same temperature range. Hydrogen flux is not observed for membranes made from the 60 and 70% STN95 samples.
Original languageEnglish
JournalJournal of Materials Chemistry A
Volume3
Issue number10
Pages (from-to)5392-5401
Number of pages10
ISSN2050-7488
DOIs
Publication statusPublished - 2015

Keywords

  • Argon
  • Ceramic materials
  • Ceramic membranes
  • Composite membranes
  • Heterojunctions
  • Composite ceramic
  • Effective medium approaches
  • Hydrogen permeability
  • Hydrogen permeation flux
  • Hydrogen separation membranes
  • Phase volume ratio
  • Semiconductor-type
  • Temperature range
  • Hydrogen

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