Structural stability and oxygen permeability of cerium lightly doped BaFeO3-delta ceramic membranes

The structural stability under reducing environment and oxygen permeation fluxes of perovskite-type BaCexCFe1-xO3-delta (0 <= x <= 0.15) ceramic membranes were investigated. The XRD results showed that 5% of cerium doping into the perovskite B-site can make the BaFeO3-delta transform from the hexagonal structure to the cubic structure, and make the structure stable under 10% H-2-Ar mixed gas at 900 degrees C for 1 h, but breaks down after 5 h. Lattice parameters and oxygen non-stoichiometry of the as-prepared and reduced samples were measured. Oxygen permeation fluxes of the membranes were measured between 700 and 950 degrees C. Oxygen permeation during the cooling and heating circles showed that 5% of cerium doping into the perovskite B-site can avoid the phase transformation. The optimum cerium-doped amount on the B-sites was found to be 10%. (c) 2006 Elsevier B.V. All rights reserved