Dense La0.1Sr0.9Co0.9Fe0.1O3−δ disks with various thicknesses and surface areas were prepared in order to investigate the contribution made by surface reactions and bulk diffusion to O permeation phenomena. The bulk diffusion-controlled situation became significant upon increasing the membrane thickness, and the surface reaction-controlled situation prevailed at lower surface areas. An increase in surface area at the low-PO2 (anode) side was more effective in increasing the O permeation flux than one at the high-PO2 (cathode) side. Coating of a porous catalyst layer of below-optimum thickness was also effective in enhancing O permeability, due to the increase in surface area. However, coating with too thick a layer degraded the permeability; due probably to an increase in gas diffusion resistance.

Surface Effect on Oxygen Permeation through Dense Membrane of Mixed-Conductive LSCF Perovskite-Type Oxide. H.Kusaba, Y.Shibata, K.Sasaki, Y.Teraoka: Solid State Ionics, 2006, 177[26-32], 2249-53