Journal article
Electrical properties and flux performance of composite ceramic hydrogen separation membranes
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.
Language: | English |
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Year: | 2015 |
Pages: | 5392-5401 |
ISSN: | 20507496 and 20507488 |
Types: | Journal article |
DOI: | 10.1039/c5ta00450k |
ORCIDs: | Bonanos, Nikolaos |