Platinum Nanoparticles Supported by a Vulcan XC-72 and PANI Doped with Trifluoromethane Sulfonic Acid Substrate As a New Electrocatalyst for Direct Methanol Fuel Cells

摘要

A film of PANI nanowires (PANI (NWs)) was deposited onto the surface of a stainless steel electrode via cyclic voltammetry. During the polymerization of aniline (ANI), PANI(NWs) were doped with trifluoromethane sulfonic acid, and the doped PANI were utilized for the fabrication of a Vulcan (C) PANI composite. Pt particles were subsequently deposited by reduction onto the C-PANI composite to produce a Pt/C-PANI electrocatalyst. The current peak during methanol oxidation, the electrochemical surface area, and the stability of the Pt/C-PANI electrocatalysts were better than those observed using Pt/C+PANI (commercial Pt/C composites containing PANI) or Pt/C electrodes. The ionic resistance of the two electrodes containing PANI were only slightly larger than those of the Pt/C and Nation solution catalysts, but electrochemical impedance spectroscopy measurements using the modified electrodes did not show a negative impedance after measurement of the open current voltage. The methanol diffusion coefficients in the Pt/C-PANI and Pt/C+PANI electrocatalysts were found to be 2.5 and 2 times higher than in the Pt/C electrode. X-ray diffractometer and scanning electron microscopy technique have been applied to investigate the crystallite size and the surface morphologies respectively. The Pt/C-PANI modified catalysts is more suitable for applying in the direct methanol fuel cells in comparison with the standard Pt catalysts.