A solid oxide electrolysis cell concept for reducing CO2 to CO was studied using a proton conducting mixed oxide - BaCe0.7Zr0.1Y0.1Yb0.06Zn0.04O3 (-) (delta) (BCZYYZ) as an electrolyte. The oxide composite mixture: Ce0.6Mn0.3Fe0.1O2-La0.6Sr0.4Fe0.9Mn0.1O3 (12.5-87.5 wt.%) was examined as enhancing catalyst electrode for CO2 reduction and proton oxidation reaction on the cathode side for avoiding coke formation. Here we demonstrate the successful electrochemical reduction of CO2 in proton conducting SOECs. During electrochemical reduction of CO2 at 700 degrees C, current densities as high as 0.5 A/cm(2) and 1 A/cm(2) at 1.3 V and 2.2 V respectively, were withdrawn even though the cell employed a 400 mu m thick BCZYYZ electrolyte support. (C) 2015 The Authors. Published by Elsevier B.V.