Details
| Original language | English |
|---|---|
| Pages (from-to) | 4765-4772 |
| Number of pages | 8 |
| Journal | Chemistry of Materials |
| Volume | 23 |
| Issue number | 21 |
| Early online date | 7 Oct 2011 |
| Publication status | Published - 8 Nov 2011 |
Abstract
Phase stability and oxygen permeation behavior of Ba0.5Sr 0.5Co0.8Fe0.2O3-δ (BSCF) dead-end tube membranes were investigated in long-term oxygen production at 950 and 750 °C. At 950 °C, the BSCF tube membranes exhibit good long-term phase stability and a stable oxygen permeation flux. However, at the intermediate temperature of 750 °C, both the oxygen permeation flux and the oxygen purity decrease continuously. This behavior is related to the formation of two secondary phases that are a hexagonal perovskite, Ba 0.5±xSr0.5±xCoO3-δ, and a trigonal mixed oxide, Ba1-xSrxCo2-yFe yO5, that evolved in the ceramic membrane made of cubic BSCF perovskite during the dynamic flow of oxygen through it. Tensile stress as a result of phase formation causes the development of cracks in the membrane, which spoil the purity of the permeated oxygen. The partial degradation of cubic BSCF perovskite in the intermediate temperature range (750 °C) was more pronounced under the strongly oxidizing conditions on the oxygen supply (feed) side than on the oxygen release (permeate) side of the membrane. The structural instability of BSCF is attributed to an unsuitable redox state of cobalt, that exhibits an ionic radius that is too small to be tolerated by the cubic perovskite structure, which then becomes unstable. The phase stability of cubic BSCF (i.e., the proper redox states of cobalt) can be maintained by operating the membrane in the high temperature regime (950 °C).
Keywords
- decomposition, mixed conductor, oxygen permeation, oxygen production, Perovskite
ASJC Scopus subject areas
- Chemistry(all)
- General Chemistry
- Chemical Engineering(all)
- General Chemical Engineering
- Materials Science(all)
- Materials Chemistry
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In: Chemistry of Materials, Vol. 23, No. 21, 08.11.2011, p. 4765-4772.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Phase stability and permeation behavior of a dead-end Ba 0.5Sr0.5Co0.8Fe0.2O 3-δ tube membrane in high-purity oxygen production
AU - Liang, Fangyi
AU - Jiang, Heqing
AU - Luo, Huixia
AU - Caro, Jürgen
AU - Feldhoff, Armin
PY - 2011/11/8
Y1 - 2011/11/8
N2 - Phase stability and oxygen permeation behavior of Ba0.5Sr 0.5Co0.8Fe0.2O3-δ (BSCF) dead-end tube membranes were investigated in long-term oxygen production at 950 and 750 °C. At 950 °C, the BSCF tube membranes exhibit good long-term phase stability and a stable oxygen permeation flux. However, at the intermediate temperature of 750 °C, both the oxygen permeation flux and the oxygen purity decrease continuously. This behavior is related to the formation of two secondary phases that are a hexagonal perovskite, Ba 0.5±xSr0.5±xCoO3-δ, and a trigonal mixed oxide, Ba1-xSrxCo2-yFe yO5, that evolved in the ceramic membrane made of cubic BSCF perovskite during the dynamic flow of oxygen through it. Tensile stress as a result of phase formation causes the development of cracks in the membrane, which spoil the purity of the permeated oxygen. The partial degradation of cubic BSCF perovskite in the intermediate temperature range (750 °C) was more pronounced under the strongly oxidizing conditions on the oxygen supply (feed) side than on the oxygen release (permeate) side of the membrane. The structural instability of BSCF is attributed to an unsuitable redox state of cobalt, that exhibits an ionic radius that is too small to be tolerated by the cubic perovskite structure, which then becomes unstable. The phase stability of cubic BSCF (i.e., the proper redox states of cobalt) can be maintained by operating the membrane in the high temperature regime (950 °C).
AB - Phase stability and oxygen permeation behavior of Ba0.5Sr 0.5Co0.8Fe0.2O3-δ (BSCF) dead-end tube membranes were investigated in long-term oxygen production at 950 and 750 °C. At 950 °C, the BSCF tube membranes exhibit good long-term phase stability and a stable oxygen permeation flux. However, at the intermediate temperature of 750 °C, both the oxygen permeation flux and the oxygen purity decrease continuously. This behavior is related to the formation of two secondary phases that are a hexagonal perovskite, Ba 0.5±xSr0.5±xCoO3-δ, and a trigonal mixed oxide, Ba1-xSrxCo2-yFe yO5, that evolved in the ceramic membrane made of cubic BSCF perovskite during the dynamic flow of oxygen through it. Tensile stress as a result of phase formation causes the development of cracks in the membrane, which spoil the purity of the permeated oxygen. The partial degradation of cubic BSCF perovskite in the intermediate temperature range (750 °C) was more pronounced under the strongly oxidizing conditions on the oxygen supply (feed) side than on the oxygen release (permeate) side of the membrane. The structural instability of BSCF is attributed to an unsuitable redox state of cobalt, that exhibits an ionic radius that is too small to be tolerated by the cubic perovskite structure, which then becomes unstable. The phase stability of cubic BSCF (i.e., the proper redox states of cobalt) can be maintained by operating the membrane in the high temperature regime (950 °C).
KW - decomposition
KW - mixed conductor
KW - oxygen permeation
KW - oxygen production
KW - Perovskite
UR - http://www.scopus.com/inward/record.url?scp=80455127477&partnerID=8YFLogxK
U2 - 10.1021/cm2018086
DO - 10.1021/cm2018086
M3 - Article
AN - SCOPUS:80455127477
VL - 23
SP - 4765
EP - 4772
JO - Chemistry of Materials
JF - Chemistry of Materials
SN - 0897-4756
IS - 21
ER -