This study presents results on PtRu electrocatalysts supported on both as received and H2O2 treated carbon black. The electrochemical properties and fuel cell performance of both home-made and commercial PtRu electrocatalysts were compared to PtRu supported on H2O2 treated carbon black. The PtRu nanoparticles were synthesized by the impregnation method and subsequent alcohol reduction. Transmission electron microscopy experiments revealed that the PtRu electrocatalysts supported on H2O2 treated carbon black are more homogeneously distributed than all other studied materials Cyclic voltammetry electrocatalyst curves, PEMFC and DMFC experiments showed higher activity for the PtRu supported on H2O2 treated carbon black. Such an enhanced performance is related to a better particle distribution of the treated carbon black and can also be inferred by the better nanoparticles utilization that are outside from the carbon pore structure, which are more exposed and available to the reactants, enhancing the fuel cell performance and avoiding the waste of noble catalysts. (C) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.