Vapor phase synthesis of double-walled carbon nanotubes
View Patent ↗A method of massively synthesizing double-walled carbon nanotubes is provided. In the method, catalyst metal particles having a size of a few nanometers are embedded in nano pores of a support material powder. Then, the support material powder embedding the catalyst metal particles is sintered at a temperature of 700-900° C. Then, the support material powder embedding the catalyst metal particles is loaded in a reactor. Thereafter, high purity double-walled carbon nanotubes are formed massively by vaporizing a carbon source solution at a temperature of 700-1100° C. and supplying the vaporized carbon source gas, or by directly supplying a carbon source gas to the reactor.
1. A method of synthesizing double-walled carbon nanotubes, the method comprising:
embedding catalyst metal particles composed of Fe, Co, Ni, Mo or an alloy of the elements and having a size of 2-5 nm in nano pores of a support material powder composed of MgO, Al 2 O 3 , zeolite or silica;
sintering the support material powder in which the catalyst metal particles are embedded; and
forming the double-walled carbon nanotubes by supplying a carbon source gas to the catalyst metal particles embedded in the support material powder and reacting the carbon source gas with the catalyst metal particles.
2. The method of claim 1 , wherein the embedding the catalyst metal particles in the nano pores of the support material powder comprises:
making a first solution including the catalyst metal particles;
mixing the first solution with the support material powder to form a second solution;
removing moisture included in the second solution; and
pulverizing the support material powder including the catalyst metal particles to form the support material powder in which the catalyst metal particles are supported.
3. The method of claim 2 , wherein the removing the moisture is performed by a vacuum oven for 15 hours at a temperature of 150° C.
4. The method of claim 2 , wherein if the second solution is a solution containing Fe, Ni or Co, Mo, and MgO, a molar ratio of Fe, Ni or Co:Mo:MgO is 0.7-1:0.1-0.3:10-13,
if the second solution is a solution containing Fe or Ni, Mo, and MgO, a molar ratio of Fe:Ni:Mo:MgO is 0.7-1:0.1-0.3:0.1-0.3:10-13, and
if the second solution is a solution containing Fe or Co, Mo, and MgO, a molar ratio of Fe:Co:Mo:MgO is 0.7-1:0.1-0.3:0.1-0.3:10-13.
5. The method of claim 1 , wherein the sintering is performed in air atmosphere for 6-12 hours at a temperature of 700-900° C.
6. The method of claim 1 , wherein the forming the double-walled carbon nanotubes comprises:
loading the support material powder embedding the catalyst metal particles in a reactor;
maintaining the temperature of the reactor including the support material powder at 700-1100° C.; and
supplying a carbon source solution selected from the group consisting of alcohol, benzene, hexane, THF (tetra hydrofuran) and propanol, to an inside of the reactor in a gas form using an evaporator.
7. The method of claim 1 , wherein the forming the double-walled carbon nanotubes comprises:
loading the support material powder embedding the catalyst metal particles in a reactor;
maintaining the temperature of the reactor including the support material powder at 700-1100° C.; and
supplying a carbon source gas selected from the group consisting of acetylene, methane, ethylene, propane and CO to an inside of the reactor.