Method for preparing monolayer carbon nanotube

Abstract

A combination of a metal-based catalyst having a function as a catalyst for formation of graphite and a single-crystal substrate having a certain correspondence to the metal-based catalyst with respect to the crystal grain size and the crystal orientation thereof is used; the metal-based catalyst is dispersed on the single-crystal substrate; and a carbon material is fed to the substrate at any temperature not lower than 500° C. to thereby form single single-walled carbon nanotubes through vapor phase thermal decomposition growth on the substrate. More precisely, the invention of this application enables production of single-walled carbon nanotubes with controlled diameter, requiring neither a porous material nor catalyst particles for use as a catalyst carrier. One example of the combination of the metal-based catalyst and the single-crystal substrate is a combination of Fe and sapphire substrate.

1 . A method for producing single-walled carbon nanotubes, which comprises using a combination of a metal-based catalyst having a function as a catalyst for formation of graphite, and a single-crystal substrate having a certain correspondence to the metal-based catalyst with respect to the crystal grain size and the crystal orientation thereof, dispersing the metal-based catalyst on the single-crystal substrate, and feeding a carbon material to the substrate at any temperature not lower than 500° C. to thereby grow single-walled carbon nanotubes through vapor phase thermal decomposition.  
     
     
         2 . The method for producing single-walled carbon nanotubes as claimed in  claim 1 , wherein the single-crystal substrate is coated with a thin film of metal-based catalyst.  
     
     
         3 . The method for producing single-walled carbon nanotubes as claimed in  claim 1 , wherein the thin film of metal-based catalyst has a thickness of from 0.1 to 10 nm.  
     
     
         4 . The method for producing single-walled carbon nanotubes as claimed in  claim 1 , wherein the metal-based catalyst is any one or a mixture of two or more components of the group consisting of iron group metals, platinum group metals, rare earth metals, transition metals and their metal compounds.  
     
     
         5 . The method for producing single-walled carbon nanotubes as claimed in  claim 1 , wherein the single-crystal substrate is formed of a substance stable at 500° C. or higher.  
     
     
         6 . The method for producing single-walled carbon nanotubes as claimed in  claim 5 , wherein the single-crystal substrate is any of sapphire (Al 2 O 3 ), silicon (Si), SiO 2 , SiC or MgO.  
     
     
         7 . The method for producing single-walled carbon nanotubes as claimed in  claim 1 , wherein hydroxyapatite is used in place of the single-crystal substrate.  
     
     
         8 . The method for producing single-walled carbon nanotubes as claimed in  claim 1 , wherein single-walled carbon nanotubes with controlled diameter are grown through vapor phase thermal decomposition, the diameter depending on the combination of the metal-based catalyst and the single-crystal substrate and its crystal plane.  
     
     
         9 . The method for producing single-walled carbon nanotubes as claimed in  claim 8 , wherein the combination of the metal-based catalyst, the single-crystal substrate and the crystal plane connecting the two is a combination of Fe and any of A-plane, R-plane or C-plane of sapphire.  
     
     
         10 . The method for producing single-walled carbon nanotubes as claimed in  claim 1 , wherein the carbon material is a carbon-containing substance that is gaseous at any temperature not lower than 500° C.  
     
     
         11 . The method for producing single-walled carbon nanotubes as claimed in  claim 10 , wherein the carbon material is methane, ethylene, phenanthrene or benzene.