Patent ID: 8795417

Claim:
A method of producing an oxygen ion composite membrane comprising: forming a first layer on a porous support containing a first mixture of particles of (Ln 1-x A x ) w Cr 1-y B y O 3-δ and doped zirconia and substantially free of pore formers, where Ln is La, Y, Pr, Ce or Sm; A is Ca, B is Fe, Mn, Co, Al, Ti or combinations thereof; w is 0.9-1.1; x is 0.1-0.4 and y is 0.1-0.6; forming a second layer on the first layer that contains a second mixture of particles of (Ln 1-x A x ) w Cr 1-y B y O 3-δ and the doped zirconia, where Ln is La, Y, Pr, Ce or Sm; A is Sr; and B is Fe, Mn, Co, Al, Ti or combinations thereof; w is 0.9-1.1; x is 0.1-0.3 and y is 0.1-0.6; and heating the first layer, the second layer and the porous support so that said first layer partially sinters into a porous mass containing the first mixture of particles, thereby to provide a porous fuel oxidation layer and the second layer fully sinters into a densified mass containing the second mixture of particles, thereby to provide a dense separation layer; wherein the partially sintered first layer contains (Ln 1-x A x ) w Cr 1-y B y O 3-δ and doped zirconia in a first volume ratio of between 2 to 3 and 4 to 1 on a volume percentile basis; and wherein the sintered second layer contains (Ln 1-x A x ) w Cr 1-y B y O 3-δ and doped zirconia in a second volume ratio of between 1 to 4 and 3 to 2 on a volume percentile basis.