Method for producing graphite nanocatalysts having improved catalytic properties

Abstract

High temperature treatment of graphite nanofibers to increase their catalytic activity. The heat treated graphite nanofiber catalysts are suitable for catalyzing chemical reactions such as oxidation, hydrogenation, oxidative-dehydrogenation, and dehydrogenation.

1 . A method for increasing the catalytic activity of graphitic nanofibers comprised of a plurality of graphite platelets that are aligned at an angle from about 1° to about 90° with respect to the longitudinal axis of the nanofibers and which nanofibers have a crystallinity greater than about 90%, which method comprises heat treating said nanofibers in an inert gas environment at temperatures from about 2300° C. to about 3000° C.  
     
     
         2 . The method of  claim 1  wherein the platelets are aligned substantially 90° with respect to the longitudinal axis of the nanofiber.  
     
     
         3 . The method of  claim 1  wherein the platelets are aligned at angle from about 30° to about 60° with respect to the longitudinal axis of the nanofibers.  
     
     
         4 . The method of  claim 1  wherein the inert gas is selected from helium and argon.  
     
     
         5 . The method of  claim 1  wherein said graphitic nanofibers are intercalated with an intercalation component selected from the group consisting of Li, Na, K, Rb, Cs, Br 2 , Cl 2 , F 2 , ICl, ICl 3 , H 2 SO 4 , HNO 3 , H 2 SeO 4 , HClO 4 , H 3 PO 4 , H 4 P 2 O 7 , H 3 AsO 4 , HF, CrO 2 Cl 2 , CrO 2 F 2 , UO 2 Cl 2 , FeCl, CuCl 2 , BCl 3 , AlCl 3 , CoCl 3 , RuCl 3 , RhCl 3 , PdCl 4 , PtCl 4 , Cr 2 O 3 , Sb 2 O 3 , MoO 3 , Sb 2 S 3 , CuS, FeS 2  Cr 2 S 3 , V 2 S 3  and WS 2 .  
     
     
         6 . A catalytic chemical reaction selected from oxidation, hydrogenation, dehydrogenation, oxidative-hydrogenation, and oxidative-dehydrogenation which is catalyzed by a catalyst composition comprised of graphitic nanofibers which nanofibers are comprised of a plurality of graphite platelets aligned at an angle from about 1° to about 90° with respect to the longitudinal axis of the nanofibers and which nanofibers have a crystallinity greater than about 90%, which method comprises heat treating said nanofibers in an inert gas environment at temperatures from about 2300° C. to about 3000° C.  
     
     
         7 . The catalytic chemical reaction of  claim 6  which is a oxidative-hydrogenation reaction.  
     
     
         8 . The catalytic chemical reaction of  claim 7  which is the oxidative-hydrogenation reaction of ethylbenzene to styrene.  
     
     
         9 . The catalytic chemical reaction of  claim 6  wherein the platelets are aligned substantially 90° with respect to the longitudinal axis of the nanofiber.  
     
     
         10 . The catalytic chemical reaction of  claim 6  wherein the platelets are aligned at angle from about 30° to about 60° with respect to the longitudinal axis of the nanofibers.  
     
     
         11 . The catalytic chemical reaction of  claim 6  wherein the inert gas is selected from helium and argon.  
     
     
         12 . The catalytic chemical reaction of  claim 8  wherein the platelets are aligned substantially 90° with respect to the longitudinal axis of the nanofiber.  
     
     
         13 . The catalytic chemical reaction of  claim 8  wherein the platelets are aligned at angle from about 30° to about 60° with respect to the longitudinal axis of the nanofibers.  
     
     
         14 . The catalytic chemical reaction of  claim 8  wherein said graphitic nanofibers are intercalated with an intercalation component selected from the group consisting of Li, Na, K, Rb, Cs, Br 2 , Cl 2 , F 2 , ICl, ICl 3 , H 2 SO 4 , HNO 3 , H 2 SeO 4 , HClO 4 , H 3 PO 4 , H 4 P 2 O 7 , H 3 AsO 4 , HF, CrO 2 Cl 2 , CrO 2 F 2 , UO 2 Cl 2 , FeCl, CuCl 2 , BCl 3 , AlCl 3 , CoCl 3 , RuCl 3 , RhCl 3 , PdCl 4 , PtCl 4 , Cr 2 O 3 , Sb 2 O 3 , MoO 3 , Sb 2 S 3 , CuS, FeS 2  Cr 2 S 3 , V 2 S 3  and WS 2 .