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 language | English |
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Journal | Journal of Materials Chemistry A |
Volume | 3 |
Issue number | 10 |
Pages (from-to) | 5392-5401 |
Number of pages | 10 |
ISSN | 2050-7488 |
DOIs | |
Publication status | Published - 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