Oxygen permeation through perovskite membranes and the improvement of oxygen flux by surface modification

BSCF hollow fiber membranes possessing an asymmetric layered structure were prepared using a modified phase inversion process followed by subsequent sintering at temperatures from 1100 to 1175 °C. The fibers were characterized by SEM, and tested for air separation at ambient pressure and temperatures between 650 and 950 °C. Although the prepared hollow fibers resulted in self-supported asymmetric substrate with a very thin densified perovskite layer for mixed conduction, O₂ permeation was controlled by surface O₂ exchange kinetics rather than bulk diffusion. In order to improve O₂ flux, surface modification was carried out by the attachment of Pt particles on the surface of the hollow fiber. The maximum O₂ flux measured for pure perovskite hollow fiber was 0.0268 mol m^-2 s^-1 at 950 °C whilst O₂ fluxes increased up to 25% after the surface modification using Pt micro-particles.