Processing and oxygen permeation studies of asymmetric multilayer Ba0.5Sr0.5Co0.8Fe0.2O3− membranes

Microwave Assisted Synthesis and Sintering of Ba0.5Sr0.5Co0.8Fe0.2O3-δ Perovskite

“…The as-prepared powder was analyzed by X-ray diffraction (XRD) using a SIEMENS D-5005 diffractometer with CuKa radiation (λ = 0.15418 nm) and by differential scanning calorimetry / thermogravimetry (DCS / TG) using a equipment Netzsch Sta 449c under heating rate of 10 °C/ min. In order to crystallize BSCF phase, the powder was treated at temperature of 900 °C according to data from DCS/TG analysis and, the treatment time was kept in two hours according to some reports 14,15 . Then, BSCF powder was subject to wet ball milling in ethanol for 12 h in order to decrease agglomeration and to provide easier densification in sintering stage.…”

“…Thereby, this architecture development suggests the using of starting powders with nanometer particles size and high specific surface area 4,[8][9][10][11] . Consequently, BSCF powders synthesis has become a subject of great relevance and the BSCF perovskite has been synthesized by several methods: conventionally by solid state reaction 12,13 , combustion synthesis reaction 14,15 , co-precipitation method 8,16 , complexing method 5,11,12 , and others 17 . Moreover, the use of microwave heating together with these synthesis methods has emerged as a novel route to produce materials in nanoscale 17 .…”

Current developments of mixed conducting membranes on porous substrates

“…In another work 36 this group verified that O 2 flux is also dependent on the direction of the permeation, i.e., the oxygen flux is higher when permeates in the support-membrane direction, due to increasing surface exchange rate on the dense layer in the high partial pressure side. In other groups an improvement of the oxygen permeation flux in supported MIEC membranes produced by dry pressing was also observed by modifying the microstructure of porous support to straight pores in order to favor gas diffusion 41 , by adding a thin porous activity layer in the permeate membrane side to increase surface area for accelerating surface exchange reaction in the low pressure side 39 . Kawahara et al 48 employed dip coating to produce thin and dense perovskite membranes on porous substrates produced by dry pressing.…”

“…Thin perovskites MIEC membrane have been deposited on porous substrates using different techniques, e.g. dry pressing [36][37][38][39][40][41][42][43][44] , dip coating [45][46][47][48] , screen printing 49,50 , spray pyrolisis 51 , slip casting 52 , tape casting 20,53-56 and others [57][58][59][60][61][62][63] . Table 1 lists some of these studies including membrane and support fabrication method, material used for both components, as well as their thickness, pore-forming agent and pore size of the support and oxygen permeation fluxes in different operating conditions.…”

Influence of porous structures on O 2 flux of BSCF asymmetric membranes

“…For example, adding carbon fiber mixed with ethyl cellulose to the porous substrate layer of BSCF [38] and SrFeCo 0.5 O x [39]. The porosity (%) in porous BSCF substrates was also investigated by Baumann and co-workers [40] and Kovalevsky et al [41]. In all these examples, there is clear evidence that the oxygen flux of the asymmetric membranes increased due to the porous layers, which provided an improvement in the oxygen molecular transport rate.…”