A rational asymmetric hollow fiber membrane for oxygen permeation

Abstract A typical oxygen permeation hollow fiber membrane fabricated by phase inversion‐based extrusion process demonstrates heterogeneous porous microstructures, in which the surface layer with relatively low porosity is used as a separation layer after sintering. It is usually not convenient to control the thickness of separation layer. And a high sintering temperature is needed to densify the separation layer, which in turn could destroy the desired porous microstructures in other portion. This paper studies a novel process to fabricate multilayer asymmetric hollow fiber membrane with a rational design using 67 vol. % Gd 0.2 Ce 0.8 O 2−δ −33 vol. % La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3−δ ( GDC ‐ LSCF ) as a model material system. The phase inversion‐based extrusion process in open literature is employed to fabricate a hollow fiber substrate featuring radially well‐aligned microchannels open at the inner surface. Built upon the hollow fiber substrate, a thin dense separation layer and porous surface catalyst layer at shell side are then fabricated through dip‐coating and sintering process alternatively. The oxygen permeation flux of the fabricated hollow fiber membrane reaches 2.68 mL/cm 2 /min at 900°C under Ar/air gradient, the highest performance of the membranes with GDC ‐ LSCF material system in open literature. The innovative fabrication process is able to readily control the thickness of functional layers while decreasing sintering temperatures.