Asymmetric Lanthanum Doped Ceria Membrane with Proton Conductive and Hydrogen Separation Capability for Solid Oxide Fuel Cell

An asymmetric lanthanum doped ceria (LDC) membrane was prepared by sintering process. The membrane consisted of two layers, dense LDC and porous Ni-LDC layers with a total thickness of approximately 850 μm. According to the XRD pattern, sintering process did not cause any chemical changes to the membrane. The membrane had a crystalline dense LDC layer with a highest hydrogen permeation flux of 1.3 × 10 -3 mol∙m -2 ∙s -1 , observed at a hydrogen partial pressure of 65.9 kPa and operating temperature of 800 o C. The hydrogen permeation increased as the partial pressure of the hydrogen gas increased. The proton conducting permeation became more dominant as the hydrogen partial pressure decreased. The highest value was observed at 20.3 kPa of hydrogen partial pressure, where 50.6% of the total permeation came from proton conducting ability of the membrane. While, the decreased in the operating temperature decreased the proton conductive permeation flux. With the decrease in the sintering temperature, the amount of pores in the dense LDC layer increased. The LDC membrane with both proton conductivity and hydrogen separation capability shows a promising potential as a hydrogen separation membrane and as a solid electrolyte for the solid oxide fuel cell.