Oxygen permeability, thermal expansion and stability of SrCo0.8Fe0.2O3−δ–SrAl2O4 composites

SrAl2O4-improved SrCo0.8Fe0.2O3−δ mixed-conducting membrane for effective production of hydrogen from methane

“…Fig. 1b shows the XRD patterns of SCF and SrAl 2 O 4 -doped SCF powders, which are calcined at 950 • C for 5 h then annealed in helium at 700 • C for 5 h. After annealing, the characteristic peaks of SCF at 2q ≈ 32 • and 58 • split, which indicates a structure transition to the oxygen-vacancy-ordered brownmillerite phase of Sr 2 CoFeO 5 [18,22]. For SCFSA3, SCFSA5, SCFSA7, and SCFSA9, no obvious changes of phase structure are observed.…”

“…The reduction of B site cations to low valence state would result in the distortion or tilting of the BO6 octahedron, which directly influences the stability of the perovskite structure. The introduction of SrAl 2 O 4 into SCF oxide leads to the inter-diffusion between the two phases and Al 3+ will diffusion into the B site of SCF lattice [22]. As Al 3+ has a stable oxidation state, the diffusion of Al 3+ into the B site leads to a moderate increase of stability of the BO6 octahedron.…”

“…Therefore, doping of the SrAl 2 O 4 increases the structural stability of the SCF oxide. However, Sr deficiency in A site is obviously intensified when the doping amount of SrAl 2 O 4 is high (≥30 mol%), which promotes the transition of perovskite to a vacancy-ordered brownmillerite structure [22]. Yaremchenko et al also reported that partial dissolution of SrAl 2 O 4 in the SrFeO 3−ı led to formation of A-site-deficient oxide [24].…”

“…Recently, the composite oxide SrAl 2 O 4 was firstly utilized by Sammells et al [20,21] to improve the mechanical stability of the mixed-conducting materials. Karthon et al [22] also introduced SrAl 2 O 4 oxide into SCF material to improve the thermal and chemical stability. They found that the addition of SrAl 2 O 4 phase to mixed-conducting SCF could not suppress the order-disorder phase transition but promoted oxygen-vacancy ordering and brownmillerite formation at temperature below 777 • C due to the fact that the amount of the SrAl 2 O 4 oxide was too high (>30 mol%) to get a optimized material with high oxygen permeation flux and good structural stability.…”

Simulation of a mixed-conducting membrane-based gas turbine power plant for CO2 capture: system level analysis of operation stability and individual process unit degradation

“…Detailed descriptions of the experimental procedures and equipment, used for processing and characterization of dense La 2 NiO 4+δ membranes and physicochemical properties of lanthanum nickelate ceramics were published in previous works ( [39,40,[47][48][49][50][56][57][58] and references cited). The oxygen permeability measurements under ambient total pressure were performed using the electrochemical cells made of yttria-stabilized zirconia solid electrolyte; high-pressure permeation tests were carried out in the stainless steel chamber where a dense ceramic membrane was hermetically sealed onto a metallic tubular support [47].…”