Influence of support layer resistance on oxygen fluxes through asymmetric membranes based on perovskite-type oxides SrTi1-xFexO3-δ

• Published in: Journal of membrane science Vol. 596
• Main Authors: Schulze-Küppers, F., Baumann, S., Meulenberg, W.A., Bouwmeester, H.J.M.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-02-2020
• Subjects: Asymmetric membranes; Oxygen transport membrane; Perovskite; SrTi1-xFexO3-δ; Perovskite; SrTi1-xFexO3-δ; Asymmetric membranes; Oxygen transport membrane
• ISSN: 0376-7388; 1873-3123
• DOI: 10.1016/j.memsci.2019.117704

Asymmetric membranes of mixed ionic-electronic conducting perovskite-type oxides SrTi1-xFexO3-δ (STF, x = 0.3, 0.5 and 0.7) were prepared by inverse sequential tape-casting. Both porous support (~600 μm) and functional membrane layer (~20 μm) for a given membrane assembly were made from the same composition to ensure thermochemical compatibility between the layers. Oxygen fluxes were assessed in the range 650 -1020 °C, using either (non-pressurized) ambient air or pure oxygen as feed gas at the support side of the asymmetric membrane and argon as sweep gas. Notably, similar oxygen fluxes (~1.2 × 10−6 mol cm−2 s−1) are measured through the membranes of different compositions above 950 °C when using ambient air as feed gas. This observation is interpreted to reflect the major role of the support layer resistance in rate-limiting the oxygen fluxes through the STF asymmetric membranes, which conclusion is supported by comparison of the oxygen fluxes with those measured previously through asymmetric membranes of Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) and La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF). A simple diffusion-convection model is used to account for the observed gas phase polarization in the porous support layers limiting the oxygen fluxes.
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•Asymmetric all-perovskite membranes were prepared by inverse sequential tape-casting.•Support layer resistances limit the oxygen fluxes when using air as feed gas.•Diffusion-convection simulations account for the observed gas phase polarization.