The CO2 reforming reaction on Ba0.5Sr0.5Co0.8Fe0.2Ox (BSCF) oxygen permeable membranes was investigated at 800 degrees C over a Pt/ZrO2 and a Pt/CeZrO2 (17.5 wt% Ce) catalyst. To determine the effect of oxygen flux on the reaction, both dense and asymmetric BCSF membranes were tested. The results showed that the oxygen permeable membrane effectively increased the activity of the catalyst and the conversion of CH4. Furthermore, the asymmetric membrane had higher oxygen flux compared to the dense BCSF membrane. A mechanism involving steam reforming due to the high oxygen flux and formation of water is proposed which is enhanced by the synergistic relationship between the catalyst and the membrane. The BSCF membranes were found to maintain mechanical stability during the reaction. However, a decrease in CH4 conversion as a function of time was observed for both the Pt/ZrO2 and Pt/CeZrO2 catalysts. This decrease is ascribed to a decrease in the oxygen flux caused by carbonate formation on the surface of the permeate side of the membrane. (C) 2010 Elsevier B.V. All rights reserved.