Use of high-purity metal-catalyst-free multiwalled carbon nanotubes to avoid potential experimental misinterpretations.

Carbon nanotubes, even after extensive posttreatment, contain metallic impurities which may produce misleading results, giving rise to false claims of the properties of carbon nanotubes. To overcome this, we report on high-purity catalyst-free multiwalled carbon nanotubes which have been explored with transmission electron microscopy, X-ray photoelectron spectroscopy, and cyclic voltammetry using the electrochemical oxidations of hydrazine and potassium ferrocyanide. The multiwalled carbon nanotubes are approximately 150 nm in length and consist of 6-10 graphite layers. Due to the definitive absence of metallic impurities, experimentalists using these carbon nanotubes can avoid potential misinterpretations of their results.