In this paper, the catalytic activity of a ferrite/ceria composite ceramic fuel electrode La0.9Ca0.1-Fe0.9Nb0.1O3-delta/Sm0.1Ce0.9O2-(delta) (LCFNb/SDC) for solid oxide reversible cells (SOCs) is studied by using YSZ (Zr0.84Y0.16O2-delta) and LSM/YSZ (LSM(La0.8Sr0.2MnO3-delta)) as electrolyte and oxygen electrode, respectively. The asymmetrical LCFNb/SDC|YSZ|LSM/YSZ cells are prepared and evaluated electrochemically by using DC (cyclic voltammetry (CV) and galvanostatic) and AC impedance techniques in 50% CO: 50% CO2 at the fuel electrode compartment. XRD results indicate LCFNb in the composite fuel electrode is stable in CO and CO2 at high temperature and the LCFNb/SDC membane fuel electrode prepared by infiltration method presents high performance towards CO2 reduction and CO oxidation. The polarization resistance under open circuit in a 50% CO: 50% CO2 gas composition at 800 degrees C is 0.97 Omega cm(2). However, both the CV and polarized impedance data show that the cell performance is higher for the electrolysis of CO2 than for the oxidation of CO. The polarization resistance in 50% CO: 50% CO2 at 1.4 V at 800 degrees C is 0.39 Omega cm(2). Notably, the cell shows a highly stable activity towards CO2 electrolysis at different applied voltages at the temperature of 800 degrees C. (C) 2017 Elsevier Ltd. All rights reserved.