The effect of modification of the surface of a La0.9Ca0.1FeO3 (LCF) membrane by the addition of a porous layer with an infiltrated catalyst on oxygen flux through the membrane in a CO/air gradient was investigated. Membranes with Pt and CeO2 catalysts on the fuel (CO) side and La0.8Sr0.2FeO3 (LSF) on the air side exhibited oxygen permeation fluxes that were 91, 28, and 5.8 times greater at 873 K, 973 K, and 1073 K, respectively, compared to a membrane with unmodified surfaces. The relative contributions of the bulk (R-b) and surface (R-s) resistances to the total resistance to oxygen ion flow (R-tot) were accessed by measuring the oxygen flux as a function of the membrane thickness. R-s was found to dominate R-tot , demonstrating the importance of the surface processes. (C) 2014 Elsevier B.V. All rights reserved.