A porous electrochemical reactor, made of La0.85Sr0.15FeO3 (LSF) as electrode and Ce0.9Gd0.1O1.95 (CGO) as electrolyte, was studied for the electrochemical oxidation of propene over a wide range of temperatures. Polarization was found to enhance propene oxidation rate. Ce0.9Gd0.1O1.95 was used as infiltration material to enhance the effect of polarization on propene oxidation rate, especially at low temperatures. The influence of infiltrated material, as a function of heat treatment, on the reactor electrochemical behavior has been evaluated by using electrochemical impedance spectroscopy. The infiltration of Ce0.9Gd0 O-1(1.95) increased the catalytic activity of the reactor and helped to mitigate the degradation of the electrode induced by prolonged polarization. The results suggested that the formation of a thin and continuous layer of Ce0.9Gd0.1O1.95 on the electrodes played a crucial role in suppressing the competing oxygen evolution reaction and promoting the oxidation of propene under polarization, with faradaic efficiencies above 70% at 250 degrees C. (c) 2014 The Electrochemical Society. All rights reserved.