Methods of making carbide and oxycarbide containing catalysts
View Patent ↗Methods for forming compositions including carbide-containing nanorods and/or oxycarbide-containing nanorods and/or carbon nanotubes bearing carbides and oxycarbides. Rigid porous structures including oxycarbide-containing nanorods and/or carbide containing nanorods and/or carbon nanotubes bearing modified carbides and oxycarbides and methods of making the same are also provided. The compositions and rigid porous structures of the invention can be used either as catalyst and/or catalyst supports in fluid phase catalytic chemical reactions. Processes for making supported catalyst for selected fluid phase catalytic reactions are also provided.
1. A method for forming a catalyst composition comprising the step of reacting carbon nanotubes with a solid Q-containing compound at temperatures between 500° C. to 1000° C. to form a carbide composition QC or Q 2 C that substantially retains the original morphology of said carbon nanotubes, said solid Q-containing compound comprising a carbide forming element Q.
2. The method of claim 1 , wherein said solid compound is MoO 3 .
3. The method of claim 2 , wherein said carbide composition is Mo 2 C.
4. The method of claim 1 , wherein said carbon nanotubes are in the form of rigid porous structures.
5. The method of claim 1 , further comprising the step of passivating said carbide composition with a gaseous mixture containing less than 5% oxygen.
6. A method for forming a catalyst composition comprising the steps of:
mixing carbon nanotubes with a solid Q containing compound comprising a carbide forming element Q,
said carbon nanotubes having a substantially uniform diameter between 1 nm and 100 nm and a length to diameter ratio greater than 5,
said carbide forming element Q selected from the group consisting of transition metal, rare earth metal or actinide;
calcining said mixture at a first temperature to melt said solid compound and disperse said carbide forming element Q onto said carbon nanotubes; and
calcining said mixture at a second temperature higher than said first temperature to form a carbide composition QC or Q 2 C that substantially retains the original morphology of said carbon nanotubes.
7. The method of claim 6 , wherein said solid compound is MoO 3 .
8. The method of claim 7 , wherein said carbide composition is Mo 2 C.
9. The method of claim 6 , wherein said first temperature is between about 400-650° C.
10. The method of claim 9 , wherein said second temperature is between about 600-1000° C.
11. The method of claim 6 , wherein said carbon nanotubes are in the form of rigid porous structures.
12. The method of claim 6 , wherein less than 75% of said carbon nanotubes have been reacted to form said carbide composition.
13. The method of claim 6 , wherein less than 50% of said carbon nanotubes have been reacted to form said carbide composition.
14. The method of claim 6 , wherein less than 25% of said carbon nanotubes have been reacted to form said carbide composition.
15. The method of claim 6 , wherein substantially all of said carbon nanotubes have been reacted to form said carbide composition.
16. The method of claim 6 , further comprising the step of passivating said carbide composition with a gaseous mixture containing less than 5% oxygen.
17. The method of claim 6 , wherein said calcining steps are performed under a vacuum.
18. The method of claim 6 , wherein said calcining steps are performed in the presence of an inert gas.