Preparation of carbon nanotubes from graphite powder at room temperature

We develop a new chemical route to prepare carbon nanotubes at room temperature. Graphite powder is immersed in a mixed solution of nitric and sulfuric acid with potassium chlorate. After heating the solution up to 70{\deg}C and leaving them in the air for 3 days, we obtained carbon nanotube bundles. This process could provide an easy and inexpensive method for the preparation of carbon nanotubes.