Z. Phys. Chem. / DOI 10.1524/zpch.2013.0422 © by Oldenbourg Wissenschaftsverlag, München On the Catalytic Activity of Ceria for Direct Carbon Conversion in a SOFC By Pauline Desclaux 1 , Matthias Rzepka 1 , ∗ , Edda Stern 2 , Michael Woiton 2 , Ulrich Stimming 3 , and Rolf Hempelmann 4 1 ZAE Bayern, Division 1, Walther-Meissner-Str. 6, 85748 Garching, Germany 2 ZAE Bayern, Division 3, Haberstr. 2a, 91058 Erlangen, Germany 3 TUM CREATE Centre for Electromobility Singapore, c/o Nanyang Technological University, 50 Nanyang Drive, #02-07, X-frontier block, Research Techno Plaza, 637553, Singapore 4 Saarland University, Department of Physical Chemistry, Campus B2 2, 66123 Saarbruecken, Germany (Received April 9, 2013; accepted in revised form June 10, 2013) (Published online July 22, 2013) DCFC / SOFC / Carbon Conversion / Ceria / Catalyst 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 R  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. 1. Introduction At medium term, the utilization of carbon in fuel cells offers many advantages due to the abundant amount of suitable fuel sources. Carbon fuel is present in different forms, such as hard coal, char, carbonized biomass or carbon-containing waste (e.g. plastic) and these materials are easy to store as well as to transport. Moreover, as the main prod- uct at the anode is carbon dioxide it makes separation easy. Therefore, a negative carbon dioxide balance is possible if the fuel materials are derived from biomass [1]. Up to now, there are three main concepts of direct carbon fuel cells (DCFCs) which differ regarding the electrolyte type [2,3]: molten carbonate [4], molten hydroxide [5] and solid oxide electrolyte [6,7]. Recently, also combined technologies have been de- veloped [8 – 13]. * Corresponding author. E-mail: rzepka@muc.zae-bayern.de