Rapidly dispersion and loading of Pt nanoparticles on CNTs for DMFC electrodes

In this article, platinum nanoparticles with uniform diameter (about 4.3 nm) were efficiently dispersed on multi-walled carbon nanotubes (MWCNTs) with temperature controlled, microwave assisted polyol method. Temperature is an important factor that affects the reduction rate of Pt particles from chloroplatinic acid. In a microwave system, chloroplatinic acid is rapidly dissociated and reduced. Pt catalyst particles are then deposited on the MWCNTs. An addition of sodium dodecyl sulfate (SDS) and poly-vinyl pyrrolidone (PVP) in chloroplatinic acid/ ethylene glycol (EG) solution can efficiently disperse the catalyst particles homogenously on MWCNT, enhance the adsorption of platinum particles, and reduce the residue of platinum particles. The results indicate that the optimal temperature range from 140 to 160°C, and that the loading amount of Pt/CNTs can achieve more than 50 wt % for only 90 seconds ofprocessing time. The significant improvement in dispersion and loading is due to the ability of SDS, which wraps the PVP-stabilized Pt nanoparticles around the surface of carbon nanotubes. The characterization analyses are conducted by using SEM, TEM, XRD, XPS, and TGA.