Effect of Polyaniline on Catalytic Activity of Platinum Nanoparticles in Direct Methanol Fuel Cells

Polyaniline (PANI) nanofibers were synthesized chemically by interfacial method. These nanofibers were doped by para toluene sulfonic acid and the doped PANIs were utilized for the fabrication of Vulcan (C) - PANI composite. Platinum (Pt) particles were subsequently deposited by reduction onto the C-PANI composite to produce Pt/C-PANI electrocatalyst. The performance of the resultant electrocatalyst was evaluated by measuring the stripping onset and peak potential of adsorbed CO,peak current density of methanol oxidation, electrochemical surface area, stability, and electrochemical impedance spectroscopy. It was shown that the existence of low content polyaniline in structure of the electrocatalyst can improve the activity of Pt nanoparticles interestingly. The current peak during methanol oxidation, the electrochemical surface area, the stability and the impedance of the Pt/C-PANI electrocatalysts were better than those observed using Pt/C+PANI (commercial Pt/Ccomposites containing PANI) or Pt/C electrodes. Also, the onset and peak potential of CO oxidation are less than those in the two mentioned electrodes; therefore, polyaniline increases the CO tolerance of Pt nanoparticles. X-ray diffractometry and transmission electron microscopy were also applied to investigate the crystallite size and the surface morphologies, espectively

کلیدواژه ها:

polyaniline ، platinum nanoparticles ، fuel cell ، methanol oxidation