Design of multilayer ceramic MIEC membranes

The development of multilayer mixed conducting oxide membranes on porous dead-end tubular mineral-based glass-ceramic supports is presented. Nanopowders of compatible complex perovskites and fluorites as membrane materials were obtained by mechanochemical synthesis. The deposition of oxide ceramic porous and dense layers was carried out by casting of slurries in organic medium, prepared from narrow fractions of agglomerated powders. A linear dependence between the sintering temperature T-s and calculated effective melting point T*(m) for complex perovskites and fluorites was revealed that allowed to propose a simple rule for the synthesis of complex oxides with required Ts. Dead-end tubular supports were produced by casting from selected kaolins with organic/inorganic additives. The misfit in sintering temperatures of porous substrate and MIEC ceramic layers was eliminated by modification of substrate and heavily doping of mixed oxides. The elimination of shrinkage misfit between the porous substrate and ceramic layers was achieved by optimization of operation conditions and compositions of both substrate and ceramics. Almost gas-tight cost efficient catalytic membrane reactors CMRs with large operation surface similar to 30 cm(2) and good prospects for up-scaling were produced and tested.