In this work, two different catalysts, Pt-Ru (1:1), Pt-Sn (1:1), supported on both non-activated and activated carbon for the electro-oxidation of ethanol were studied in a H3PO4 doped polybenzimidazole-based fuel cell, using vapor fed ethanol and operating in the range of 150-200 degrees C. The catalysts were synthesized using NaBH4 as reducing agent and were characterized by X-ray diffraction, inductively coupled plasma-atomic emission spectroscopy and temperature programmed reduction. The best performance was reached at the highest temperature and with the catalyst based on Pt-Ru/C-act, using activated carbon as support. The best results for the Ru-based catalyst can be explained by the higher level of alloying reached for the Ru than that for Sn, which modifies the crystalline structure of Pt and enhances the activity oxidation of ethanol and of intermediates that can be generated during the oxidation of ethanol. (C) 2009 Elsevier B.V. All rights reserved.