Synthesis of small and narrow diameter distributed carbon single walled nanotubes

Abstract

Method and processes for synthesizing single-wall carbon nanotubes is provided. A carbon precursor gas is contacted with metal deposited on a support material. The metal catalysts are preferably nanoparticles having diameters less than about 50 nm. The reaction temperature is selected such that it is near the eutectic point of the mixture of metal catalyst particles and carbon.

1 . A chemical vapor deposition method for the preparation of single-wall carbon nanotubes (SWNT), the method comprising: 
 contacting a carbon precursor gas with a catalyst on a support at a temperature near the eutectic point of the catalyst wherein SWNT having narrow distribution of diameters are formed.    
     
     
         2 . The method of  claim 1 , wherein the carbon precursor gas is methane.  
     
     
         3 . The method of  claim 2 , wherein the carbon precursor gas further comprises an inert gas and hydrogen.  
     
     
         4 . The method of  claim 3 , wherein the inert gas is argon, helium, nitrogen, hydrogen, or combinations thereof.  
     
     
         5 . The method of  claim 1 , wherein the catalyst is iron, molybdenum, or combinations thereof.  
     
     
         6 . The method of  claim 1 , wherein the catalyst has a particle size between 1 nm to 10 nm.  
     
     
         7 . The method of  claim 6 , wherein the catalyst has a particle size of about 1 nm.  
     
     
         8 . The method of  claim 6 , wherein the catalyst has a particle size of about 3 nm.  
     
     
         9 . The method of  claim 6 , wherein the catalyst has a particle size of about 5 nm.  
     
     
         10 . The method of  claim 1 , wherein the support is a powdered oxide.  
     
     
         11 . The method of  claim 10 , wherein the powdered oxide is selected from the group consisting of Al 2 O 3 , SiO 3 , MgO and zeolites.  
     
     
         12 . The method of  claim 11 , wherein the powdered oxide is Al 2 O 3 .  
     
     
         13 . The method of  claim 1 , wherein the catalyst and the support are in a ratio of about 1:1 to about 1:50.  
     
     
         14 . The method of  claim 13 , wherein the ratio is about 1:5 to about 1:25.  
     
     
         15 . The method of  claim 14 , wherein the ratio is about 1:10 to about 1:20.  
     
     
         16 . The method of  claim 1 , wherein the temperature is about 5° C. to about 150° C. above the eutectic point.  
     
     
         17 . The method of  claim 16 , wherein the temperature is about 10° C. to about 100° C. above the eutectic point.  
     
     
         18 . The method of  claim 1 , wherein the temperature is about 50° C. above the eutectic point.  
     
     
         19 . The method of  claim 18 , wherein the temperature is about 80° C. above the eutectic point.  
     
     
         20 . A chemical vapor deposition method for the preparation of single-wall carbon nanotubes (SWNT), the method comprising: 
 contacting a carbon precursor gas with a catalyst on a support at a temperature less than the melting point of the catalyst and about 5° C. to about 150° C. above the eutectic point of the catalyst wherein SWNT are formed.    
     
     
         21 . The method of  claim 20 , wherein the carbon precursor gas is methane.  
     
     
         22 . The method of  claim 21 , wherein the carbon precursor gas further comprises an inert gas and hydrogen.  
     
     
         23 . The method of  claim 22 , wherein the inert gas is argon, helium, nitrogen, hydrogen, or combinations thereof.  
     
     
         24 . The method of  claim 20 , wherein the catalyst is iron, molybdenum, or combinations thereof.  
     
     
         25 . The method of  claim 20 , wherein the catalyst has a particle size between 1 nm to 10 nm.  
     
     
         26 . The method of  claim 25 , wherein the catalyst has a particle size of about 1 nm.  
     
     
         27 . The method of  claim 25 , wherein the catalyst has a particle size of about 3 nm.  
     
     
         28 . The method of  claim 25 , wherein the catalyst has a particle size of about 5 nm.  
     
     
         29 . The method of  claim 20 , wherein the support is a powdered oxide selected from the group consisting of Al 2 O 3 , SiO 3 , MgO and zeolites.  
     
     
         30 . The method of  claim 29 , wherein the powdered oxide is Al 2 O 3 .  
     
     
         31 . The method of  claim 20 , wherein the catalyst and the support are in a ratio of about 1:1 to about 1:50.  
     
     
         32 . The method of  claim 31 , wherein the ratio is about 1:5 to about 1:25.  
     
     
         33 . The method of  claim 32 , wherein the ratio is about 1:10 to about 1:20.  
     
     
         34 . The method of  claim 20 , wherein the temperature is about 10° C. to about 100° C. above the eutectic point.  
     
     
         35 . The method of  claim 20 , wherein the temperature is about 50° C. above the eutectic point.  
     
     
         36 . The method of  claim 35 , wherein the temperature is about 80° C. above the eutectic point.  
     
     
         37 . The method of  claim 20 , wherein the SWNTs have a diameter of about 0.8 nm to about 2 nm.  
     
     
         38 . A single-wall carbon nanotube (SWNT) produced by the process of: 
 contacting a carbon precursor gas with a catalyst on a support selected from the group consisting of Al 2 O 3 , SiO 3 , MgO and zeolite; and    maintaining reaction temperature between the melting point of the catalyst and the eutectic point of the catalyst.    
     
     
         39 . The process of  claim 38 , wherein the carbon precursor gas is methane.  
     
     
         40 . The process of  claim 39 , wherein the carbon precursor gas further comprises an inert gas and hydrogen.  
     
     
         41 . The process of  claim 40 , wherein the inert gas is argon, helium, nitrogen, hydrogen, or combinations thereof.  
     
     
         42 . The process of  claim 38 , wherein the catalyst is iron, molybdenum, or combinations thereof  
     
     
         43 . The process of  claim 38 , wherein the catalyst has a particle size between 1 nm to 10 nm.  
     
     
         44 . The process of  claim 43 , wherein the catalyst has a particle size of about 1 nm.  
     
     
         45 . The process of  claim 38 , wherein the powdered oxide is Al 2 O 3 .  
     
     
         46 . The process of  claim 38 , wherein the catalyst and the support are in a ratio of about 1:1 to about 1:50.  
     
     
         47 . The process of  claim 50 , wherein the temperature is about 1:10 to about 1:20.  
     
     
         48 . The process of  claim 38 , wherein a temperature is about 10° C. to about 100° C. above the eutectic point.  
     
     
         49 . The process of  claim 38 , wherein the temperature is about 50° C. above the eutectic point.  
     
     
         50 . The process of  claim 38 , wherein the temperature is about 80° C. above the eutectic point.