Purification of single-wall carbon nanotubes produced by arc plasma jet method

In the arc plasma jet method, a large amount of soot including single-wall carbon nanotubes (SWNTs) can be produced in a short time (1–2 g/min). However, a lot of impurities, such as amorphous carbon and catalyst metals, are included in the produced soot besides SWNT. Purification is indispensable to apply SWNTs industrially, but it was difficult until recently. Here, we report that SWNTs can be purified easily in large quantities by reflux in the hydrogen peroxide solution using catalyst of iron particle, which can activate the oxidation reaction of hydrogen peroxide solution. Higher than 90 wt.% purity of SWNTs are obtained by this technique.