Direct electro-oxidation of iso-octane in a solid electrolyte fuel cell

The present work aims to explore the activity of Cu/CeO2 composites as anodic electrodes in direct iso-octane SOFCs. When the cell was operated as a membrane reactor, the effect of temperature, Pi-C8H18 and applied anodic overpotentials on the electrocatalytic activity and products' distribution, at both open and closed circuit conditions, was examined. Additionally, in situ DRIFT spectroscopy was carried out in order to correlate the performance of Cu/CeO2 with its surface chemistry during iso-octane decomposition. Under the "fuel cell" mode of operation, the electrochemical performance and stability of Cu/CeO2 were investigated by voltage-current density-power density and AC impedance measurements. The results reveal that at high anodic polarization conditions, carbon formation can be noticeably restricted (verified also by EDAX analysis), while H-2 production was enhanced due to partial oxidation, steam reforming, dehydrogenation and water gas shift reactions. Achieved power densities were found to substantially increase both with temperature and Pi-C8H18, while minor performance degradation was indicated in the step-change tests, where the overall activity of Cu-CeO2 electrodes remained essentially unaffected. (C) 2010 Elsevier B.V. All rights reserved.