A New Series of Sr(Co,Fe,Zr)O_3-δ Perovskite-Type Membrane Materials for Oxygen Permeation

Abstract

A new series of SrCo 0.4 Fe 0.6-x Zr x O 3-δ (0 e x e 0.2) and SrCo 0.95-x Fe x Zr 0.05 O 3-δ (0.1 e x e 0.8) oxides were synthesized by the solid-state reaction method. The incorporation of Zr and its effect on the crystal chemistry, oxygen permeation, and structural stability of SrCo 0.4 Fe 0.6-x Zr x O 3-δ have been investigated. Formation of the solid solutions with the cubic perovskite-type structure was found in the SrCo 0.4 Fe 0.6-x Zr x O 3-δ oxide system in the range of 0 e x < 0.1. The incorporation of the proper content of Zr into SrCo 0.4 Fe 0.6 O 3-δ suppressed the oxygen loss at high temperature and could stabilize the cubic structure of perovskite in a low oxygen partial pressure atmosphere, while the oxygen permeability of SrCo 0.4 Fe 0.6-x Zr x O 3-δ membranes decreased with increasing Zr content. A total of 5 mol % of Zr cation dissolution was considered to be enough for the structural stability without deleteriously affecting the oxygen flux. Meanwhile, an investigation of the effect of the Co content on the oxygen permeation and structural stability of SrCo 0.95-x Fe x Zr 0.05 O 3-δ series oxides showed that, with increasing Co content, the oxygen permeability increased, but no phase transition occurred in low oxygen partial pressure for all of the samples investigated. Our results indicated that the content of Zr played a critical role in the stability of Sr-Co-Fe-Zr-O series oxides. When good structural stability and oxygen permeation properties are combined, these Sr(Co,Fe,Zr)O 3-δ oxides are considered to be promising candidates as oxygen separation membranes.

In-situ X-ray diffraction study of carbonate formation and decomposition in perovskite-type BCFZ

“…Note, the co-existence of two cubic perovskite phases after doping of 5-10% Zr was also reported for similar perovskite systems like Ba 0.5 Sr 0.5 Co 0. 8 [17,18]. The high-temperature XRD pattern taken from the BCFZ powder annealed at 1173 K for 30 min in the flowing synthetic air evidences no structural changes.…”

Match of thermal performances between the membrane and the support for supported dense mixed-conducting membranes

“…SCFZ powders were synthesized by the conventional solidstate reaction method, which was the same as our previous work [19]. The calcined powders were reground and sifted to an average particle size of about 8 m, which was analyzed by a laser granulometer (MALVERN, model ZETASIZER 3000HSA).…”

“…incorporating the support material into the membrane and simultaneously merging the membrane material into the support, and then the supported dense mixed-conducting membrane is formed by the co-sintering route. SrCo 0.4 Fe 0.5 Zr 0.1 O 3−δ (SCFZ) mixed oxygen ionic and electronic conducting oxide is selected as the representative membrane material, which was found to be structurally stable with higher oxygen permeability in our previous work [19]. And MgO is selected as the support material because of its excellent thermal, chemical and mechanical properties with the mixed conducing oxides [20,21].…”

Effects of sintering atmospheres on sintering behavior, electrical conductivity and oxygen permeability of mixed-conducting membranes

“…SCFZ powders were synthesized using the conventional solid-state reaction method, which was similar to that in our previous study [14].…”

“…The sintering atmospheres were generated by mixing oxygen and nitrogen. SrCo 0.4 Fe 0.5 Zr 0.1 O 3−δ (SCFZ) perovskite-type MIEC oxide, which was found to be of structural stability and higher oxygen permeability in our previous work [14], was selected to prepare the membranes in this study.…”