Methods of Making Carbide And Oxycarbide Containing Catalysts

• US 20070179050A1
• Filed: 12/08/2006
• Published: 08/02/2007
• Est. Priority Date: 01/12/1999
• Status: Active Grant

• Current Assignee: Hyperion Catalysis International Incorporated
• Original Assignee: Hyperion Catalysis International Incorporated
• Inventors: Ma, Jun, Moy, David
• Granted Patent: US 7,576,027 B2
• Time in Patent Office: Days
• US Class Current: 502/182
• CPC Class Codes: B01J 21/185 Carbon nanotubes carbon nanotubes per se C01B32/15
• CPC Class Codes: B01J 23/28 Molybdenum
• CPC Class Codes: B01J 27/22 Carbides
• CPC Class Codes: B01J 37/08 Heat treatment B01J37/0009, B01J37/0018 take precedence
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: C01B 32/168 After-treatment
• CPC Class Codes: C01B 32/18 Nanoonions; Nanoscrolls; Nanohorns; Nanocones; Nanowalls
• CPC Class Codes: C01B 32/90 Carbides
• CPC Class Codes: Y10S 977/742 Carbon nanotubes, CNTs
• CPC Class Codes: Y10S 977/745 having a modified surface
• CPC Class Codes: Y10S 977/748 Modified with atoms or molecules bonded to the surface
• CPC Class Codes: Y10S 977/749 Modified with dissimilar atoms or molecules substituted for carbon atoms of the cnt, e.g. impurity doping or compositional substitution
• CPC Class Codes: Y10S 977/788 Of specified organic or carbon-based composition
• CPC Class Codes: Y10S 977/81 Of specified metal or metal alloy composition
• CPC Class Codes: Y10S 977/811 Of specified metal oxide composition, e.g. conducting or semiconducting compositions such as ITO, ZnOx
• CPC Class Codes: Y10S 977/847 Surface modifications, e.g. functionalization, coating

Abstract

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.

Claims

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 Q₂C 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 MoO₃.

3. The method of claim 2, wherein said carbide composition is Mo₂C.

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 Q₂C that substantially retains the original morphology of said carbon nanotubes.

7. The method of claim 6, wherein said solid compound is MoO₃.

8. The method of claim 7, wherein said carbide composition is Mo₂C.

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.