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, O 2 permeation was controlled by surface O 2 exchange kinetics rather than bulk diffusion. In order to improve O 2 flux, surface modification was carried out by the attachment of Pt particles on the surface of the hollow fiber. The maximum O 2 flux measured for pure perovskite hollow fiber was 0.0268molm −2 s −1 at 950°C whilst O 2 fluxes increased up to 25% after the surface modification using Pt micro-particles.