In this work Pt-Ru/C alloys were prepared by chemical reduction using various modifications of the formic acid method with the objective of improving the performance. The supported alloys were characterized by XRD, backscattering and TEM analyses, and the active areas were determined by CO adsorption. The materials showed similar particle sizes and different morphological characteristics. The performance of the supported alloys for methanol electrooxidation was evaluated by linear sweep voltammetry experiments and curves of cell potential vs. current density in a single direct methanol fuel cell. It is shown that the difference in the morphology of the catalysts in nano- and microscale is the main effect in the different performances. (C) 2003 Elsevier Ltd. All rights reserved.