In the present study, polypyrrole-carbon black (Ppy-C) composite is synthesized via in situ chemical polymerization method and then Pt nanoparticles are deposited on the surface of Ppy-C, where tartaric acid is employed as both a reductant and a stabilizer for Pt nanoparticles. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) indicate that Pt nanoparticles have a higher dispersion and smaller particle size (similar to 2.3 nm) on Ppy-C composite than that on carbon black. Electrochemical measurements show that Pt/Ppy-C catalyst Exhibits 60% higher electrocatalytic activity towards methanol oxidation than Pt/C. X-ray photoelectron spectroscopy (XPS) characterization indicates Pt4f binding energy in Pt/Ppy-C is shifted by + 0.2 eV as compared with that in Pt/C, while N 1s binding energy in Pt/Ppy-C shifted by -0.5 eV as compared with that in Ppy-C composite. The Pt-pyridinic nitrogen sites suppress the posioning CO adsorption on Pt nanoparticles and facilitate the methanol electrocatalytic oxidation. This work is important for the understanding of the role of Ppy in the fuel cell electrocatalyst, and the development of advanced catalysts for methanol oxidation. (C) 2011 Elsevier B.V. All rights reserved.