TY - JOUR
T1 - Temperature-Induced Structural Reorganization of W-Doped Ba0.5Sr0.5Co0.8Fe0.2O3−δ Composite Membranes for Air Separation
AU - He, Guanghu
AU - Lan, Qianqian
AU - Sohn, Yoo Jung
AU - Baumann, Stefan
AU - Dunin-Borkowski, Rafal
AU - Meulenberg, Wilhelm A.
AU - Jiang, Heqing
PY - 2019/9/24
Y1 - 2019/9/24
N2 - The practical use of Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) prototypical oxygen-transport membrane for air separation is currently hampered by the decomposition of the cubic perovskite into a variant with hexagonal stacking at intermediate temperatures of ≤850 °C, which impairs the oxygen transport. Here, we report the development of a W-doped BSCF composite that contains Fe-rich single perovskite (SP) and W-rich double perovskite (DP) phases with different crystallographic parameters. In contrast to BSCF, the BSCFW SP/DP composite maintains its cubic structure at 800 °C for 200 h, demonstrating its structural stability at intermediate temperatures. We use X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy to show that the enhanced phase stability of the composite is associated with a temperature-induced SP-DP dynamic interaction, which involves W and Fe interdiffusion between the SP and DP phases, dynamically adjusting the chemical composition and limiting structural distortion and new phase formation. The composite exhibits a stable permeation performance in the oxygen-transport membrane during over 150 h operation at 800 and 700 °C, confirming the potential of intermediate-temperature oxygen-transport membranes for air separation and providing insight for designing thermally stable composite oxides.
AB - The practical use of Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) prototypical oxygen-transport membrane for air separation is currently hampered by the decomposition of the cubic perovskite into a variant with hexagonal stacking at intermediate temperatures of ≤850 °C, which impairs the oxygen transport. Here, we report the development of a W-doped BSCF composite that contains Fe-rich single perovskite (SP) and W-rich double perovskite (DP) phases with different crystallographic parameters. In contrast to BSCF, the BSCFW SP/DP composite maintains its cubic structure at 800 °C for 200 h, demonstrating its structural stability at intermediate temperatures. We use X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy to show that the enhanced phase stability of the composite is associated with a temperature-induced SP-DP dynamic interaction, which involves W and Fe interdiffusion between the SP and DP phases, dynamically adjusting the chemical composition and limiting structural distortion and new phase formation. The composite exhibits a stable permeation performance in the oxygen-transport membrane during over 150 h operation at 800 and 700 °C, confirming the potential of intermediate-temperature oxygen-transport membranes for air separation and providing insight for designing thermally stable composite oxides.
KW - n/a OA procedure
UR - http://www.scopus.com/inward/record.url?scp=85072647313&partnerID=8YFLogxK
U2 - 10.1021/acs.chemmater.9b02213
DO - 10.1021/acs.chemmater.9b02213
M3 - Article
AN - SCOPUS:85072647313
SN - 0897-4756
VL - 31
SP - 7487
EP - 7492
JO - Chemistry of materials
JF - Chemistry of materials
IS - 18
ER -