Carbon supported PtSb catalysts were synthesized by codeposition of platinum and antimony on Vulcan (R) carbon black. X-ray diffraction (XRD) analysis revealed that the SI) was alloyed with the Pt while XPS indicated that a large fraction of the SI) was in an oxidized state, with only partial alloying. The performances of catalysts with a range of compositions were compared in a multi-anode direct formic acid fuel cell (DFAFC). A 0.29 mol fraction of Sb was found to provide the best performance with a maximum specific power output of 280 Wg(-1) Pt. CO stripping results indicated that the addition of Sb at this optimum level greatly suppressed both CO adsorption and H adsorption/desorption, as well as promoting oxidative stripping of CO. The results are compared with those for previously studied catalysts prepared by the reductive deposition of Sb on a carbon supported Pt catalyst. (C) 2011 Elsevier B.V. All rights reserved.