| Proton exchange membrane fuel cell (PEMFC) has wide applications and broad prospects due to its high efficiency, safety, cleanness and low start temperature. The most important component of PEMFC is film electrode, and the catalysts play a vital role in the performance of PEMFC. Nowadays Pt based catalysts are supported on amorphous carbon black, which has relatively smaller in specific surface area and lower graphitization degree. That reduced the efficiency of catalyst. In order to improve the utilization of Pt, this paper chose double-wall carbon nanotubes (DWCNTs) as the carrier. We demonstrated a new approach of dispersing double-wall carbon nanotubes and the performance when they serve as the catalyst carrier of PEMFC.The double-wall carbon nanotubes are offered by our group, which is made by floating catalyst chemical vapor deposition (CVD) method. Compared with other dispersing agents, like water, methanol, and ethanol, et al., experiments show that ethylene glycol is more excellent in dispersing DWCNTs without any addition of a surfactant. Homogeneous DWCNTs/EG solution can be obtained after ultrasonication for 24 h. There is no deposit can be found after let the solution alone in 72 h. The ATR-FTIR technique and Raman spectroscopy results show that the surface structure and crystallinity of the DWCNTs after dispersion treatment are the same as before.The Pt/DWCNTs catalysts are produced by reducing choroplatinic acid in ethylene glycol system. Its carrier is well dispersed DWCNTs in EG. XRD patterns and TEM images suggest that the Pt particles are well distributed and very small. The average diameter is about 3-5 nm.Experimental results suggest that the electrochemical activities of the Pt/DWCNTs catalysts are different with the reaction temperature. We found that the best reaction temperature is 140°C and performed an analysis. The experiment also show that the catalytic effect of well dispersed DWCNTs carrier is more excellent than as-purified DWCNTs. |
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