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

A Comparative Study of the Performance of SrCo0.76Fe0.19Al0.1Ox and (SrCo0.8Fe0.2O3−δ)0.95(SrAl2O4)0.05 Mixed‐Conducting Membranes

“…To date, several ways have been proposed to improve the structural stability of SCF, such as substituting A and/ or B site cations with more stable metal ions and introducing certain amounts of second phase oxides into the perovskite‐type oxides . In our previous work, we found that introducing small amounts of the second phase SrAl 2 O 4 into SCF could stabilize the crystal structure and the 5 wt% SrAl 2 O 4 ‐doped SCF membrane was successfully operated in the partial oxidation of methane (POM) reaction for more than 1200 h without cracking . It was found that SrAl 2 O 4 and SCF systems can form solid solutions completely when the doping amount of SrAl 2 O 4 was low (<9 wt%).…”

A novel porous‐dense dual‐layer composite membrane reactor with long‐term stability

“…29 Moreover, the surfaces of Ba(Co x Fe y M 1-x-y )O 3-d (M 5 Nb, Ta, Zr) decomposed when they were used for partial oxidation of methane in coke oven gas, POM, and coupling of water splitting with the dehydrogenation of ethane. 15,30,31 36,37 have been used to improve the stability of the membrane materials for membrane reactors. Even several cobalt-free perovskite membranes materials such as SrAl According to recent study, due to the issues of stability and permeability, we have to notice that it is difficult for those materials to be independently used in the membrane reactors, especially for multireaction system.…”

“…A trade-off between high oxygen permeation and good stability was found in single-layer membranes that suffer from the erosion when they were developed to conduct oxygen ions effectively. In our previous experiment, we have used varied single-layer membrane reactors for POM, 8,36,37 oxidative stream reforming of methane, 27 thermal decomposition of CO 2 , 23,45 decomposition of CO 2 coupled with POM, 46 and bio-ethanol oxidative steam reforming coupled with water splitting. 18 However, these applications for membrane reactors involved the contacting of membrane surface with reacting environments such as reducing or carbon-rich atmospheres.…”

Photo-quenched of the luminiscence signal in Co(II)-doped alumina prepared by the sol–gel method

“…The properties of Co-doped alumina depend on the spatial distribution of the cobalt atoms into the matrix. They can be uniformly distributed forming a solid solution, or can be segregated to produce a composite or nano-composite, depending on the size of the aggregates [20,21]. The formation of a solid solution depends on the following conditions [20]: a) the ratio of the ionic radii of both cations should not be larger than 1.15.…”

“…They can be uniformly distributed forming a solid solution, or can be segregated to produce a composite or nano-composite, depending on the size of the aggregates [20,21]. The formation of a solid solution depends on the following conditions [20]: a) the ratio of the ionic radii of both cations should not be larger than 1.15. In this case the ratio of Al and Co ionic radii is 1.3 which is slightly larger than the permitted value, meaning that the cobalt atoms produce a slight distortion in the lattice structure; b) similarity between crystalline structures: the α-alumina has a hexagonal close-packed cell structure, while CoO has a fcc structure; this difference in the crystalline structure reduces the possibility to obtain a solid solution; c) the coordination sphere of the cations: Al has a coordination of 4, 5, and 6, while Co has a coordination of 4, 5, 6 and 8, meaning that the coordination does not represent a problem for the solid solution formation; d) the electronegativity of the cations should be similar to each other: the electronegativity of Al is 1.61 and that of Co 1.88; because this is not a large difference in electronegativities, this condition does not represent a limitation to form a solid solution [22][23][24].…”