Shortened Carbon Nanotubes as Enhanced Support for High-performance Platinum Catalysts

Carbon nanotubes (CNTs) were shortened from 5 to 15 mu m to ca. 200 nm using ball milling with ethanol as the milling aid agent, and a platinum catalyst with these shortened carbon nanotubes (SCNTs) as the support was prepared by a high-pressure colloidal method. It was found that this catalyst with SCNTs showed much higher activity than a platinum catalyst with normal CNTs as support; for methanol anodic oxidation, the activity of the Pt/SCNTs was 50% higher than that of the Pt/CNTs, and the Pt/SCNTs also showed higher activity for the cathodic reduction of oxygen. The Pt/SCNTs were characterised by X-ray diffraction scan-ning and transmission electron microscropy. It is suggested that the significant performance enhancement when SCNTs are used as support might result from the generation of new surfaces and defects, the opening of closed nanotubes in the process of milling, higher platinum dispersion on the shortened nanotubes and the interaction of platinum nanoparticles with the SCNTs.