Methods for synthesis of high quality carbon single-walled nanotubes

Abstract

Methods and processes for synthesizing high quality carbon single-walled nanotubes (SWNTs) are provided. A carbon precursor gas is contacted with a catalyst deposited on a support. The temperature and the duration of the reaction are varied to produce SWNTs with the ratio of G-band to D-band in Raman spectra (I G :I D ) of about 5 to about 70.

1 . A method for synthesizing carbon single-walled nanotubes (SWNTs), the method comprising: 
 contacting supported metal catalyst with a carbon precursor gas, wherein SWNTs are synthesized with a ratio of G-band to D-band in Raman spectra (I G :I D ) of greater than 5.    
     
     
         2 . The method of  claim 1 , wherein the catalyst is selected from the group consisting of a Group V metal, a Group VI metal, a Group VII metal, a Group VIII metal, a lanthanide, and a transition metal, or mixtures thereof.  
     
     
         3 . The method of  claim 2 , wherein the catalyst is Fe and another metal selected from the group consisting of V, Nb, Cr, W, Mo, Mn, Re, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt, Ce, Eu, Er, Yb, Ag, Au, Zn, Cd, Sc, Y, and La or mixtures thereof.  
     
     
         4 . The method of  claim 3 , wherein the catalyst is Fe and Ni, Co, Cr, or Mo, and combinations thereof.  
     
     
         5 . The method of  claim 4 , wherein the catalyst is selected from the group consisting Fe—Mo, Fe—Co and Ni—Fe—Mo.  
     
     
         6 . The method of  claim 1 , wherein the support is a powdered oxide.  
     
     
         7 . The method of  claim 6 , wherein the powdered oxide is oxide is selected from the group consisting of Al 2 O 3 , SiO 3 , MgO and zeolites.  
     
     
         8 . The method of  claim 7 , wherein the powdered oxide is Al 2 O 3 .  
     
     
         9 . The method of  claim 1 , wherein the catalyst and the support are in a ratio of about 1:1 to about 1:50.  
     
     
         10 . The method of  claim 9 , wherein the ratio is about 1:10 to about 1:20.  
     
     
         11 . The method of  claim 1 , wherein the carbon precursor gas is selected from the group consisting of carbon monoxide, methane, ethane, propane, butane, pentane, hexane, ethylene, acetylene, propylene, acetone, and methanol  
     
     
         12 . The method of  claim 11 , wherein the carbon precursor gas is methane.  
     
     
         13 . The method of  claim 11 , wherein the carbon precursor gas further comprises an inert gas and hydrogen.  
     
     
         14 . The method of  claim 13 , wherein the inert gas is argon, helium, nitrogen, hydrogen, or combinations thereof.  
     
     
         15 . The method of  claim 1 , wherein the ratio of I G :I D  is less than 100.  
     
     
         16 . The method of  claim 15 , wherein the ratio of I G :I D  is about 5 to about 30.  
     
     
         17 . The method of  claim 15 , wherein the ratio of I G :I D  is about 5 to about 20.  
     
     
         18 . A method for synthesizing carbon single-walled nanotubes (SWNTs), the method comprising: 
 contacting metal catalyst on a support in a ratio of about 1:10 to about 1:20 with a carbon precursor gas, wherein SWNTs are synthesized with a ratio of G-band to D-band in Raman spectra (I G :I D ) of greater than 5, and wherein the metal catalyst is selected from the group consisting Fe—Mo, Fe—Co and Ni—Fe—Mo.    
     
     
         19 . The method of  claim 18 , wherein the support is a powdered oxide.  
     
     
         20 . The method of  claim 19 , wherein the powdered oxide is oxide is selected from the group consisting of Al 2 O 3 , SiO 3 , MgO and zeolites.  
     
     
         21 . The method of  claim 20 , wherein the powdered oxide is Al 2 O 3 .  
     
     
         22 . The method of  claim 18 , wherein the carbon precursor gas is selected from the group consisting of carbon monoxide, methane, ethane, propane, butane, pentane, hexane, ethylene, acetylene, propylene, acetone, and methanol  
     
     
         23 . The method of  claim 22 , wherein the carbon precursor gas is methane.  
     
     
         24 . The method of  claim 22 , wherein the carbon precursor gas further comprises an inert gas and hydrogen.  
     
     
         25 . The method of  claim 24 , wherein the inert gas is argon, helium, nitrogen, hydrogen, or combinations thereof.  
     
     
         26 . The method of  claim 18 , wherein the ratio of I G :I D  is less than 100.  
     
     
         27 . The method of  claim 26 , wherein the ratio of I G :I D  is about 5 to about 30.  
     
     
         28 . The method of  claim 26 , wherein the ratio of I G :I D  is about 5 to about 20.  
     
     
         29 . The method of  claim 18 , wherein the reaction temperature is less than about 750° C. and the reaction duration is less than about 90 min.