On the catalytic activity of ceria for direct carbon conversion in a SOFC

Direct carbon fuel cells (DCFCs) are very promising systems to provide electricity at medium term due to the more efficient utilization of carbon at high temperatures. In this work, the focus is on a DCFC operating with a SOFC system. Button cells with an anode layer for carbon conversion, based on gadolinia-doped ceria (GDC) and CuO, are used in the experimental setup. Different contents of ceria have been incorporated in the electrode composition to test its catalytic activity for the direct carbon conversion. Vulcan ^® XC72 is used in the fuel cell as carbon fuel, and results in the temperature range of 750-850 °C are presented. Performing measurements of YSZ-based cells with or without anode layers as well as a systematic analysis of the anodic off-gas composition, it can be demonstrated that ceria catalyzes both reactions: the direct carbon conversion and in particular the partial oxidation of carbon. Moreover, it has been found that the DCFC system is dominated by the complete oxidation of carbon.