The last 10 years an alternative production route for oxygen production by using mixed conductors has been investigated. Perovskite mixed electron-oxygen conducting membranes are bulk membranes with a thickness of the order of 1 mm, showing sufficient oxygen fluxes only at temperatures above 800 degreesC. To reach commercially interesting fluxes at lower temperatures, membrane modules with a much higher surface/volume ratio or multilayer membranes with a thin dense skin need to be developed. In our laboratory, dense hollow fibres and porous multilayer substrates were synthesised. The hollow fibres were produced using a polymeric spinning technique based on phase inversion. The multilayer porous substrates were manufactured following conventional ceramic processing routes. (C) 2000 Elsevier Science B.V. All rights reserved.