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.