In this work, a catalyst based on nanostructured RuMoySez compounds was prepared by thermolysis of their carbonyl compounds in organic solvents. Evaluation of the catalytic activity was carried out via cyclic voltammetry on carbon paper. Synthesized catalyst was supported either by carbon black (Vulcan XC-72) or by polyaniline coated carbon black. The oxygen reduction activity and methanol tolerance of both electrodes was compared with commercial E-TEK 20% Pt-C electrode and polyaniline coated commercial E-TEK 20% Pt-C electrode. Characterisation of the catalysts was made using XRD and SEM. An important increase in the oxygen reduction reaction rate was observed using polyaniline coated carbon black matrix. (c) 2005 Elsevier B.V. All rights reserved.