Oxygen permeation studies of SrCo0.8Fe0.2O3 − δ

Qiu, L.

doi:10.1016/0167-2738(94)00296-5

Cited by 328 publications

(188 citation statements)

References 15 publications

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“…To enhance the rate of reaction at the surfaces of LSCo samples so as to make lattice oxygen diffusion the rate-determining step, a thin layer of SCF, which has been reported previously to have the highest oxygen permeation flux among the MIECs discovered, 20,21 was applied directly by pasting an SCF ink either on one surface of LSCo or on both. The SCF ink was made by thoroughly mixing fine SCF powders with organic binder ͑V-6 manufactured by Heraeus Inc.͒, terpineol, and oleic acid in a certain ratio.…”

Section: Methodsmentioning

confidence: 99%

Oxygen Permeation Through Cobalt-Containing Perovskites: Surface Oxygen Exchange vs. Lattice Oxygen Diffusion

Huang¹,

Goodenough²

2001

J. Electrochem. Soc.

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The oxygen permeation fluxes from p O 2 Ј to p O 2 Љ (p O 2 Ј Ͼ p O 2 Љ ) across cobalt-containing perovskite ceramic membranes La 1Ϫx Sr x CoO 3Ϫ␦ and SrCo 0.8 Fe 0.2 O 3Ϫ␦ were measured by gas chromatography as functions of oxygen chemical potential gradient, temperature, thickness, and catalytic activity on the surface. Power indexes 0.5 Ͼ n Ͼ 0 for uncatalyzed La 1Ϫx Sr x CoO 3Ϫ␦ and 1 Ͼ n Ͼ 0.5 for SrCo 0.8 Fe 0.2 O 3Ϫ␦ were obtained when J O 2 vs. p O 2 Ј n Ϫ p O 2 Љ n was plotted as a straight line. The results clearly indicate an overall permeation process controlled by both surface oxygen exchange and bulk oxygen diffusion for uncatalyzed La 1Ϫx Sr x CoO 3Ϫ␦ and SrCo 0.8 Fe 0.2 O 3Ϫ␦ . Application of a thin layer of catalytically active SrCo 0.8 Fe 0.2 O 3Ϫ␦ on the feeding-gas surface of La 0.5 Sr 0.5 CoO 3Ϫ␦ under the condition of a fixed p O 2 Ј ϭ0.21 atm and a varied p O 2 Љ not only increases remarkably the overall oxygen flux, but also changes a mixed control to a bulk diffusion control. This enables evaluation of the bulk transport properties of the mixed conductors. A coat of SrCo 0.8 Fe 0.2 O 3Ϫ␦ on the permeate side has little catalytic effect, especially at low p O 2 Љrange, due to the formation of a poorly conducting brownmillerite phase. The results explicitly show a higher activation energy for the surface exchange kinetics than for the ambipolar transport in the mixed conductors. The mechanism of the surface exchange is discussed, and an analytic expression that agrees well with the experimental results is obtained.

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Section: Methodsmentioning

confidence: 99%

Oxygen Permeation Through Cobalt-Containing Perovskites: Surface Oxygen Exchange vs. Lattice Oxygen Diffusion

Huang¹,

Goodenough²

2001

J. Electrochem. Soc.

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“…Depending on the simplification applied to the Nernst-Einstein relation for the ionic conductivity, different empirical correlations for bulk diffusion have been proposed [42,[46][47][48][49]. Due to the high electronic conductivity of mixed-conducting ceramic membranes, the concentration of electrons is maintained constant across the ITM at steady state.…”

Section: Bulk Diffusionmentioning

confidence: 99%

Numerical simulation of ion transport membrane reactors: Oxygen permeation and transport and fuel conversion

Hong

Kirchen

Ghoniem

2012

Journal of Membrane Science

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Ion transport membrane (ITM) based reactors have been suggested as a novel technology for several applications including fuel reforming and oxy-fuel combustion, which integrates air separation and fuel conversion while reducing complexity and the associated energy penalty. To utilize this technology more effectively, it is necessary to develop a better understanding of the fundamental processes of oxygen transport and fuel conversion in the immediate vicinity of the membrane. In this paper, a numerical model that spatially resolves the gas flow, transport and reactions is presented. The model incorporates detailed gas phase chemistry and transport. The model is used to express the oxygen permeation flux in terms of the oxygen concentrations at the membrane surface given data on the bulk concentration, which is necessary for cases when mass transfer limitations on the permeate side are important and for reactive flow modeling. The simulation results show the dependence of oxygen transport and fuel conversion on the geometry and flow parameters including the membrane temperature, feed and sweep gas flow, oxygen concentration in the feed and fuel concentration in the sweep gas.

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“…Up to 1/4 of the oxygen sites can be vacant like, for example, SrCo 0.8 Fe 0.2 -O 3Àd and Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3Àd . 7,8 A drawback is that these materials are prone to carbonation. An oxygen-impermeable alkaline-earth carbonate layer will be formed on the membrane surface exposed to the CO 2 -containing sweep gas, resulting in a decline of the oxygen permeation ux with time.…”

Section: Introductionmentioning

confidence: 99%

A new CO₂-resistant Ruddlesden–Popper oxide with superior oxygen transport: A-site deficient (Pr_0.9La_0.1)_1.9(Ni_0.74Cu_0.21Ga_0.05)O_4+δ

et al. 2015

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A-site deficient (Pr 0.9 La 0.1 ) 1.9 Ni 0.74 Cu 0.21 Ga 0.05 O 4+d ((PL) 1.9 NCG), with the K 2 NiF 4 structure, is found to exhibit higher oxygen transport rates compared with its cation-stoichiometric parent phase. A stable oxygen permeation flux of 4.6 Â 10 À7 mol cm À2 s À1 at 900 C at a membrane thickness of 0.6 mm is measured, using either helium or pure CO 2 as sweep gas at a flow rate of 30 mL min À1 . The oxygen flux is more than two times higher than that observed through A-site stoichiometric (PL) 2.0 NCG membranes operated under similar conditions. The high oxygen transport rates found for (PL) 1.9 NCG are attributed to highly mobile oxygen vacancies, compensating A-site deficiency. The high stability against carbonation gives (PL) 1.9 NCG potential for use, e.g., as a membrane in oxy-fuel combustion processes with CO 2 capture.

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Oxygen permeation studies of SrCo0.8Fe0.2O3 − δ

Cited by 328 publications

References 15 publications

Oxygen Permeation Through Cobalt-Containing Perovskites: Surface Oxygen Exchange vs. Lattice Oxygen Diffusion

Oxygen Permeation Through Cobalt-Containing Perovskites: Surface Oxygen Exchange vs. Lattice Oxygen Diffusion

Numerical simulation of ion transport membrane reactors: Oxygen permeation and transport and fuel conversion

A new CO₂-resistant Ruddlesden–Popper oxide with superior oxygen transport: A-site deficient (Pr_0.9La_0.1)_1.9(Ni_0.74Cu_0.21Ga_0.05)O_4+δ

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Oxygen permeation studies of SrCo0.8Fe0.2O3 − δ

Cited by 328 publications

References 15 publications

Oxygen Permeation Through Cobalt-Containing Perovskites: Surface Oxygen Exchange vs. Lattice Oxygen Diffusion

Oxygen Permeation Through Cobalt-Containing Perovskites: Surface Oxygen Exchange vs. Lattice Oxygen Diffusion

Numerical simulation of ion transport membrane reactors: Oxygen permeation and transport and fuel conversion

A new CO2-resistant Ruddlesden–Popper oxide with superior oxygen transport: A-site deficient (Pr0.9La0.1)1.9(Ni0.74Cu0.21Ga0.05)O4+δ

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A new CO₂-resistant Ruddlesden–Popper oxide with superior oxygen transport: A-site deficient (Pr_0.9La_0.1)_1.9(Ni_0.74Cu_0.21Ga_0.05)O_4+δ