Patent ID: 8206624

Claim:
A method for preparing carbon nanotubes consisting of the steps of: (a) mixing uniformly a polymer and a metallic catalyst with a solvent to form a mixture; (b) spreading the mixture on a base plate at a pressure of 0.1 Mpa and drying the mixture by removing the solvent at a pressure of 0.1 MPa; and (c) heating the dried mixture with a multiple heating stage process at a pressure of 0.1 MPa in a reaction chamber filled with an inert gas to form the carbon nanotubes, the multiple heating stage process including a first heating stage at a first predetermined temperature in a range from 200° C. to less than 400° C. at the pressure of 0.1 MPa, and a second heating stage at a second predetermined temperature of 400-800° C. at the pressure of 0.1 MPa to carry out thermal decomposition.