Hollow-fiber membranes with an asymmetrical layered structure were prepared by using a modified phase inversion process, followed by sintering at 1100 to 1175C. The fibers were characterized by means of scanning electron microscopy and were tested for air separation at ambient pressure and 650 to 950C. Although the prepared hollow fibers resulted in a self-supported asymmetrical substrate with a very thin densified perovskite layer for mixed conduction, the O2 permeation was controlled by surface O2 exchange kinetics rather than by bulk diffusion. In order to improve the O2 flux, surface modification was carried out by attaching Pt particles to the surface of the hollow fiber. The maximum O2 flux measured for pure perovskite hollow fibers was 0.0268mol/m2s at 950C. The O2 flux increased by up to 25% following surface modification using Pt micro-particles.

Oxygen Permeation through Perovskite Membranes and the Improvement of Oxygen Flux by Surface Modification. A.Leo, S.Liu, J.C.Diniz da Costa, Z.Shao: Science and Technology of Advanced Materials, 2006, 7[8], 819-25