Synthesis and characterization of Pt supported on multiwalled carbon nanotubes for improved catalytic performance in fuel cell applications

Commercially available multiwalled carbon nanotubes (MWCNTs) were functionalized using a mixture of HNO3 and H2SO4 in refluxing condition under three different reaction times (1, 3, and 5 h). The Pt loaded on functionalized MWCNTs (f-MWCNTs) (Pt/1f, 3f & 5f-MWCNTs) were prepared by reducing chloroplatinic acid and for comparison Pt loaded on pristine MWCNTs (Pt/MWCNTs) was also prepared. The size of Pt nanoparticles was determined using X-ray diffraction method. The uniform dispersion of the Pt catalyst on CNTs was confirmed by HRSEM and HRTEM. Surface area and pore size were calculated by Brunauer Emmett Teller analysis method. Five membrane electrode assembly sets were prepared (Pt/MWCNTs, Pt/1f, 3f, 5f-MWCNTs and commercial Pt/C) and tested in the fuel cell assembly. The first four were prepared using SPEEK membrane as electrolyte with the synthesized Pt/f-MWCNTs catalysts and the fifth one was prepared using commercial Nafion-117 electrolyte and Pt/C electrode for comparison.