Pt/SWNT-Pt/C nanocomposite electrocatalysts for proton-exchange membrane fuel cells

Single-walled carbon nanotubes (SWNT) have been synthesized by pyrolysis of methane over Mm (Mischmetal)-based AB3 alloy hydride catalyst. Purification of as-grown SWNT was carried out by air oxidation followed by acid treatment. The as-grown and purified SWNT have been characterized by XRD, SEM, TEM, HRTEM, TGA, IR, and Raman spectroscopy studies. Well-dispersed Pt catalysts on SWNT catalyst support for polymer electrolyte membrane fuel cells (PEMFC) have been prepared by a simple chemical reduction method using prefunctionalized SWNT. The anode and cathode electrodes for PEMFC have been fabricated using Pt-supported SWNT and commercial Pt/C electrocatalysts with different compositions of Pt/SWNT and Pt/C. The dependence of the fuel cell performance on the dispersion and accessibility of SWNT support and Pt electrocatalysts in the electrocatalyst mixture for the oxygen reduction reaction in PEMFC has been discussed. These results open up a way to use Pt/SWNT + Pt/C nanocomposites as electrocatalysts in PEMFC. © 2007 American Chemical Society.