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Oxygen Transport Kinetics in La0.5Sro0.5Fe0.8Ga0.2O3−δ Membranes Under Both Small and Large Oxygen Partial Pressure Gradients

Published online by Cambridge University Press:  10 February 2011

Sangtae Kim
Affiliation:
Department of Chemistry, University of Houston, Houston, TX 77204-5641
Allan J. Jacobson
Affiliation:
Department of Chemistry, University of Houston, Houston, TX 77204-5641
Benjamin Abeles
Affiliation:
Department of Chemistry, University of Houston, Houston, TX 77204-5641
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Abstract

Oxygen permeation through a new perovskite La0.5Sr0.5Fe0.8Ga0.2O3−δ membrane has been measured both under small (air/He) and large (air/CO, CO2) oxygen partial pressure gradients. In both cases oxygen transport is close to surface limited. By modeling the pressure dependence of the oxygen flow rate under small pressure gradient an ambipolar diffusion coefficient 9.65 × 10−7cm2/s and a surface exchange coefficient 7.15 × 10−6 cm/s at 974 °C were determined. With air/CO, CO2 on the permeate side, the permeability increases linearly with the partial pressure of CO. The observed increase is greater than the maximum enhancement predicted by our model.

Type
Research Article
Copyright
Copyright © Materials Research Society 1999

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References

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