High surface area graphene-supported metal chalcogenide assembly

Patent metadata

Field	Value
Publication number	US-9314777-B2
Application number	US-201313844225-A
Country	US
Kind code	B2
Filing date	Mar 15, 2013
Priority date	Jul 27, 2012
Publication date	Apr 19, 2016
Grant date	Apr 19, 2016

Abstract

A composition comprising at least one graphene-supported assembly, which comprises a three-dimensional network of graphene sheets crosslinked by covalent carbon bonds, and at least one metal chalcogenide compound disposed on said graphene sheets, wherein the chalcogen of said metal chalcogenide compound is selected from S, Se and Te. Also disclosed are methods for making and using the graphene-supported assembly, including graphene-supported MoS 2 . Monoliths with high surface area and conductivity can be achieved. Lower operating temperatures in some applications can be achieved. Pore size and volume can be tuned.

First claim

What is claimed is:

1. A composition comprising at least one graphene-supported assembly, which comprises(i) a three-dimensional network of graphene sheets crosslinked by covalent carbon bonds and (ii) at least one metal chalcogenide compound disposed on said graphene sheets, wherein the chalcogen of said metal chalcogenide compound is selected from S, Se and Te, and wherein the metal chalcogenide compound accounts for at least 20 wt. % of the graphene-supported assembly.

2. The composition of claim 1 , wherein metal chalcogenide compound is a catalyst for hydrogenation, hydrodeoxygenation, hydrodesulfurization, hydrodenitrogenation, and/or hydrocracking.

3. The composition of claim 1 , wherein the graphene-supported assembly is electrically conductive.

4. The composition of claim 1 , wherein the graphene-supported assembly has a conductivity of at least 0.5 S/cm.

5. The composition of claim 1 , wherein the graphene-supported assembly is a monolith having a size of at least 1 mm 3 , or in the form of a powder produced by grinding or ball-milling said monolith.

6. The composition of claim 1 , wherein the graphene-supported assembly has an elastic modulus of at least 10 MPa.

7. The composition of claim 1 , wherein the chalcogen is S.

8. The composition of claim 1 , wherein the metal chalcogenide compound comprises one or more of Mo, W, Fe, Cd, In, Zn, Ni and Co.

9. The composition of claim 1 , wherein the metal chalcogenide compound comprises Mo and optionally comprises another metal.

10. The composition of claim 1 , wherein the metal chalcogenide compound comprises MoS 2 ,WS 2 , In 2 S 3 , CdTe, ZnTe, or any combination thereof.

11. The composition of claim 1 , wherein the metal chalcogenide compound comprises MoS 2 .

12. The composition of claim 1 , wherein the graphene-supported assembly has a surface area of at least 250 m 2 /g.

13. The composition of claim 1 , wherein the graphene-supported assembly has a mesopore volume of at least 0.5 cm 3 /g.

14. The composition of claim 1 , wherein the metal chalcogenide compound comprises MoS 2 , wherein the metal chalcogenide compound accounts for at least 30 wt % of the graphene-supported assembly, wherein the graphene-supported assembly has a surface area of at least 300 m 2 /g; and wherein the graphene-supported assembly is a monolith having a size of at least 1 mm 3 .

15. The composition of claim 1 , wherein the surfaces of the graphene sheets are substantially free of carbon nanoparticles, and wherein the covalent carbon bonds crosslinking the grapheme sheets are primarily sp 2 bonds.

16. The composition of claim 1 , wherein the metal chalcogenide compound is Ni—Mo-sulfide or Co—Mo-sulfide.

17. The composition of claim 1 , further comprising (iii) at least one metal oxide, metal carbide or metal nitride deposited on said graphene sheets.

18. A method for making the composition of claim 1 , comprising:
preparing a reaction mixture comprising (i) graphene oxide (GO), (ii) at least one precursor of a metal chalcogenide compound, and (iii) at least one catalyst;
curing the reaction mixture to produce a gel;
reducing the gel with at least one reducing agent;
drying the gel to produce a graphene-based monolith.

19. The method of claim 18 , wherein the reaction mixture comprises at least one organic solvent and/or water.

20. The method of claim 18 , wherein the catalyst comprises ammonium hydroxide.

21. The method of claim 18 , wherein the reducing agent comprises hydrazine.

22. The method of claim 18 , wherein the precursor of the metal chalcogenide compound is (NH 4 ) 2 MoS 4 .

23. The method of claim 18 , wherein the reaction mixture is cured at a temperature of 100° C. or less.

24. The method of claim 18 , wherein the reaction mixture is cured at ambient pressure.

25. The method of claim 18 , wherein the step of drying the gel comprises solvent exchange.

26. The method of claim 18 , wherein the step of drying the gel comprises supercritical drying.

27. The method of claim 18 , wherein metal chalcogenide compound is MoS 2 .

28. The method of claim 18 , wherein metal chalcogenide compound is MoS 2 , and wherein the method further comprises incorporating Ni or Co into the graphene-supported assembly.

29. The method of claim 18 , comprising simultaneous gelation and reduction of grapheme oxide and (NH 4 ) 2 MoS 4 at a temperatures of 100° C. or less.

30. The method of claim 18 , comprising:
dispersing GO in a solution of DMF and water via bath sonication to produce a suspension,
dissolved (NH 4 ) 2 MoS 4 into said suspension,
adding ammonium hydroxide to said suspension,
heating said suspension to produce a first gel,
adding hydrazine to said first gel,
heating said first gel and said hydrazine to produce a second gel,
washing said second gel in acetone, and
supercritically drying said second gel with liquid carbon dioxide.

31. A method for producing the composition of claim 1 , comprising:
providing a graphene aerogel, wherein the graphene aerogel comprises a three-dimensional network of graphene sheets crosslinked by covalent carbon bonds;
immersing said graphene aerogel in a solution comprising at least one precursor of a metal chalcogenide compound to form a mixture;
curing said mixture to obtain a wet gel;
drying said wet gel to obtain a dry gel; and
annealing said dry gel to obtain the graphene-supported assembly.

32. The method of claim 31 , wherein the step of curing comprises curing wet gel at a temperature of 100° C. or less, wherein the step of drying comprises solvent exchange and supercritical drying, and wherein the step of annealing comprises annealing the dry gel at least 600° C. in an inert atmosphere.

33. The method of claim 31 , wherein metal chalcogenide compound is MoS 2 , and wherein the method further comprises incorporating Ni or Co into the graphene-supported assembly.

34. A graphene-supported assembly comprising a three-dimensional network of covalently interconnected graphene sheets and MOS 2 disposed on said graphene sheets, wherein the MOS 2 accounts for at least 20 wt. % of the graphene-supported assembly.

Assignees

• L Livermore Nat Security Llc

Inventors

• Worsley Marcus A
• Kuntz Joshua
• Orme Christine A

Classifications

• B01J35/56

  Foraminous structures having flow-through passages or channels, e.g. grids or three-dimensional [3D] monoliths · CPC title

• B01J27/04

  Sulfides · CPC title

• B01J37/036

  to form a gel or a cogel · CPC title

• B01J21/18

  Carbon · CPC title

• C10G49/04

  containing nickel, cobalt, chromium, molybdenum, or tungsten metals, or compounds thereof · CPC title