Nanocomposites of PtRu nanoparticles and polyaniline (an electronically conducting polymer) were synthesized by the borohydride reduction method in an aqueous solution for the anode electrode in direct methanol fuel cells (DMFCs). Due to the high electronic conductivity of polyaniline, the methanol oxidation current for polyaniline supported PtRu nanocomposites was similar to that of carbon supported PtRu catalysts. In addition, Pd-impregnated nanocomposite Nafion membranes were suggested to enhance DMFC performance by blocking or reducing methanol crossover and their characteristics were affected by the impregnation time of Pd-nanoparticles. (c) 2005 Elsevier B.V. All rights reserved.