An electrochemical membrane reactor using Bi4Cu0.2V1.8O11-delta as a solid electrolyte membrane was employed to investigate the selective oxidation of propane to acrylic acid over a MoV0.3Te0.17Nb0.12O catalyst. By applying an external current to the membrane reactor, the ionic oxygen was pumped to the surface of the MoV0.3Te0.17Nb0.12O catalyst, which exhibited higher conversion of propane and selectivity to acrylic acid than that in the fixed-bed reactor. The results indicate that the enhancement of catalytic performance in the membrane reactor is mainly due to the presence of the lattice oxygen, which has been proved to be necessary for the formation of acrylic acid. Thus, the Au/Bi4Cu0.2V1.8O11-delta/Au/MoVTeNbO membrane reactor achieved a higher conversion of propane (42%) and selectivity to acrylic acid (79.6%) at 380 degrees C with a 0.6 A current. (C) 2009 Elsevier B.V. All rights reserved