High yiel vapor phase deposition method for large scale sing walled carbon nanotube preparation

Abstract

An improved vapor phase deposition method for preparation of single walled carbon nanotubes on an aerogel supported metal catalyst. The total yield of SWCNTs often is at least about 100%, based the weight of the catalyst, for a reaction time of at least about 30 minutes.

What is claimed is:  
     
         1 . A method of preparing single walled carbon nanotubes comprising depositing a carbon-containing compound under vapor phase conditions onto a supported catalyst comprising a metal catalyst and an aerogel support while heating under reaction conditions of temperature sufficient and time sufficient to form the single walled carbon nanotubes on the aerogel supported catalyst.  
     
     
         2 . The method of  claim 1 , where the carbon-containing compound has a molecular weight of 28 or less.  
     
     
         3 . The method of  claim 2 , where the carbon-containing compound is selected from the group consisting of methane, carbon monoxide, and combinations thereof.  
     
     
         4 . The method of  claim 1 , where the carbon-containing compound has a molecular weight greater than 28 and is mixed with hydrogen.  
     
     
         5 . The method of  claim 4 , where the carbon-containing compound is selected from the group consisting of ethylene, benzene, and combinations thereof.  
     
     
         6 . The method of  claim 1 , where the metal catalyst is selected from the group consisting of Fe/Mo, Fe/Pt, and combinations thereof.  
     
     
         7 . The method of  claim 1 , where the aerogel support is selected from the group consisting of Al 2 O 3  aerogel support, Al 2 O 3 /SiO 2  aerogel support, and combinations thereof.  
     
     
         8 . The method of  claim 1 , where said depositing is with a sufficient flow rate of the carbon-containing compound, with sufficient heat for a sufficient time, to obtain a yield of at least about 100% based on the weight of the catalyst.  
     
     
         9 . The method of  claim 8 , where the sufficient flow rate ranges from about 900 sccm to about 1300 sccm.  
     
     
         10 . The method of  claim 1 , where the aerogel supported catalyst has a surface area of from about 500 m 2 /g to about 600 m 2 /g.  
     
     
         11 . The method of  claim 1 , where the aerogel supported catalyst has been dried by drying selected from the group consisting of supercritical drying, freeze drying, and combinations thereof.  
     
     
         12 . The method of  claim 11 , where the supercritical drying is selected from the group consisting of CO 2  supercritical drying, ethanol supercritical drying, and combinations thereof.  
     
     
         13 . The method of  claim 11 , where the freeze drying is freeze drying using water.  
     
     
         14 . The method of  claim 1 , where the sufficient heat provides a temperature ranging from about 750° C. to about 1000° C.  
     
     
         15 . The method of  claim 1 , where the sufficient time is at least about 0.25 hours.  
     
     
         16 . The method of  claim 1 , where the yield is at least about 100%.  
     
     
         17 . The method of  claim 1 , further including separating the single walled carbon nanotubes from the aerogel supported catalyst.  
     
     
         18 . A method of preparing single walled carbon nanotubes comprising depositing a carbon-containing compound under vapor phase conditions onto a supported catalyst comprising a metal catalyst and an aerogel support where the carbon-containing compound is selected from the group consisting of methane, carbon monoxide, and combinations thereof, where the metal catalyst is selected from the group consisting of Fe/Mo, Fe/Pt, and combinations thereof, where the aerogel support is selected from the group consisting of Al 2 O 3  aerogel support, Al 2 O 3 /SiO 2  aerogel support, and combinations thereof, where the aerogel supported catalyst has been dried by drying selected from the group consisting of supercritical drying, freeze drying, and combinations thereof, and where said depositing is with a sufficient flow rate of the carbon-containing compound, with sufficient heat for a sufficient time, to obtain a yield of at least about 100% based on the weight of the catalyst.