Investigation of Zr-doped BSCF perovskite membrane for oxygen separation in the intermediate temperature range

Journal Article · Wed May 01 04:00:00 EDT 2013 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/J.JSSC.2013.02.023· OSTI ID:22306273

Ravkina, Olga ^[1]; Klande, Tobias; Feldhoff, Armin ^[1]

---

1. Gottfried Wilhelm Leibniz Universität Hannover, Institute of Physical Chemistry and Electrochemistry, Callinstr. 3A, 30167 Hannover (Germany)

The series of (Ba₀.₅Sr₀.₅)(Co₀.₈Fe₀.₂){sub 1–z}Zr{sub z}O{sub 3–δ} (z=0, 0.01, 0.03, 0.05, 0.07, and 0.09) was synthesized by a sol–gel method. The materials with a zirconium content up to 3 mol% were found to be single phase. Further increase results in formation of a mixed (Ba,Sr)ZrO₃ by-phase, which was found along the grain boundaries and in the grains. With increasing zirconium content the oxygen permeation flux decreases considerably. The effect of the zirconium substitution on the long-term phase stability was investigated by long-term oxygen permeation experiments and X-ray diffraction. A slight stabilization of the oxygen flux of (Ba₀.₅Sr{sub 0.5})(Co₀.₈Fe₀.₂)₀.₉₇Zr₀.₀₃O{sub 3–δ} was found after 180 h at 1023 K. However, all compositions show a decrease in permeation flux with time, but the pure BSCF membrane exhibited the strongest drop after 180 h of operation. The decomposition products of the cubic perovskite phase were found to be a hexagonal Ba{sub 0.5±x}Sr{sub 0.5±x}CoO₃ and a rhombohedral Ba{sub 1–x}Sr{sub x}Co{sub 2–y}Fe{sub y}O{sub 5–δ}. - Graphical abstract: Backscattered-electron channeling contrast image of BSCF membrane cross-section after long-term oxygen permeation at 1023 K showing different phases in different colors. Highlights: • Ba₀.₅Sr₀.₅Co₀.₈Fe₀.₂O{sub 3–δ} systematically doped with increasing amount of zirconium. • Cubic single-phase materials up to 3 wt% zirconium. • Mixed (Ba,Sr)ZrO₃ by-phase formed mainly in the grain boundaries. • Jänecke prism was proposed by XRD and EDXS data. • (Ba₀.₅Sr₀.₅)(Co₀.₈Fe₀.₂)₀.₉₇Zr₀.₀₃O{sub 3–δ} showed a slight stabilization of oxygen flux as compared to pure Ba₀.₅Sr₀.₅Co₀.₈Fe₀.₂O{sub 3–δ}.

• OSTI ID: 22306273
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Vol. 201; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
CROSS SECTIONS
DECOMPOSITION
DOPED MATERIALS
ELECTRON CHANNELING
GRAIN BOUNDARIES
MEMBRANES
OXYGEN
PEROVSKITE
PHASE STABILITY
SOL-GEL PROCESS
STABILIZATION
TEMPERATURE RANGE
TRANSMISSION ELECTRON MICROSCOPY
TRIGONAL LATTICES
X-RAY DIFFRACTION
ZIRCONATES
ZIRCONIUM