Oxygen Permeation and Methane Conversion Properties of CERIA-Based Composite Membranes Prepared by Tape-Casting Technique

The preparation of ceria-based composite membranes by means of tape-casting technique and their oxygen permeation and methane reforming properties have been investigated. Oxide powders comprising of Ce_1−xRE_xO_2−δ (RE = Pr and Sm) and spinel-type ferrites of MFe₂O₄ (M = Mn and Co) were prepared by the citrate-based liquid-mix technique. As a result of the optimization of ceramics slurry composition, a crack-free dense membrane with dimensions of 5 cm × 5 cm and 140 μm in thickness was successfully prepared by means of doctor-blade technique. For Ce_0.9Sm_0.1O_2−δ - 15 vol% MnFe₂O₄ membrane with a thickness of 133 μm, an oxygen flux density of 9.5 μmol/cm² s was attained at 1000 °C under Ar-10% CH₄ (100 sccm). The methane conversion and CO selectivity were 22 and 93%, respectively. Laminated membranes comprising of Ce_0.9Sm_0.1O_2−δ - 15 vol% MnFe₂O₄ and Ce_0.9Sm_0.1O_2−δ - 30 vol% CoFe₂O₄ were also prepared. The laminated membrane with one Ce_0.9Sm_0.1O_2−δ - 30 vol% CoFe₂O₄ layer showed a higher oxygen flux density by a factor of 40% than that without Ce_0.9Sm_0.1O_2−δ - 30 vol% CoFe₂O₄ layer.