Facile synthesis of novel Pt-Ru@PPy-MWNT electrocatalysts for direct methanol fuel cells

Pt-Ru@polymer-multiwall carbon nanotubes (MWNT) composites were successfully prepared as electrocatalysts by loading Pt-Ru nanoparticles onto the surface of polymer coated-MWNT Polymers such as poly(beta-caprolactone), poly(maleic anhydride), and poly(pyrrole) Polymer coating on the surface of MWNT was performed by in sun polymerization of the respective monomer in the presence of MWNT Pt-Ru nanoparticles were deposited onto polymer-MWNT composite by the reduction of the metal ions (Pt4+ and Ru3+) using gamma-iriadiation Thus, Pt-Ru@polymer-MWNT catalysts were obtained The PtRu@polymer-MWNT catalysts were characterized by transmission electron microscopy (TEM). X-ray diffraction analysis (XRD) and elemental analysis for morphology, size and composition, respectively The polymer was found to be coated to a thickness of 5-35 nm over the surface of MWNT TEM images of the Pt-Ru@polymer-MWNT composite indicates that Pt-Ru alloy nanoparticles are more dispersed on the surface of polymer-MWNT composites as compared to the surface of pristine MWNT The surface of polymer-MWNT is changed to hydrophilic as compared to the hydrophobic surface of pristine MWNT The catalytic efficiency of Pt-Ru@polymer-MWNT catalyst was examined for the oxidation of carbon monoxide (CO) and methanol The electrodes fabricated with Pt-Ru@PPy-MWNT and Pt-Ru@PMA-MWNT show enhanced activity for the electro-oxidation of methanol over the Pt-Ru@PCL-MWNT electrode Also, results from stripping voltammetry for the adsorbed CO at Pt-Ru@polymer-MWNT catalyst electrodes inform that CO oxidation is energetically favorable at these electrodes Thus, Pt-Ru@polymer-MWNT catalysts are suited for the electrode assembly in direct methanol fuel cells (C) 2009 Elsevier B V All rights reserved