Activated carbon cryogels and related methods

• US 8,158,556 B2
• Filed: 03/26/2010
• Issued: 04/17/2012
• Est. Priority Date: 11/21/2005
• Status: Active Grant

• Current Assignee: BASF SE
• Original Assignee: EnerG2, Inc., University of Washington
• Inventors: Cao, Guozhong, Feaver, Aaron M
• Primary Examiner(s): MCCRACKEN, DANIEL
• Application Number:
  US12/748,219
• Publication Number:
  US 20100331179A1
• Time in Patent Office: 753 Days
• Field of Search: 502416-439
• US Class Current: 502/416
• CPC Class Codes: B01J 20/20 comprising free carbon; comprising carbon obtained by carbonising processes
• CPC Class Codes: B01J 20/28011 Other properties, e.g. density, crush strength
• CPC Class Codes: B01J 20/28047 Gels
• CPC Class Codes: B01J 20/28057 Surface area, e.g. B.E.T specific surface area
• CPC Class Codes: B01J 20/28076 being more than 1.0 ml/g
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C01B 3/0021 Carbon, e.g. active carbon, carbon nanotubes, fullerenes; Treatment thereof
• CPC Class Codes: C01B 32/00 Carbon; Compounds thereof C01B21/00, C01B23/00 take precedence; percarbonates C01B15/10; carbon black C09C1/48
• CPC Class Codes: F17C 11/005 for hydrogen
• CPC Class Codes: F17C 11/007 for hydrocarbon gases, such as methane or natural gas, propane, butane or mixtures thereof [LPG]
• CPC Class Codes: Y02E 60/32 Hydrogen storage

Abstract

Carbon cryogels, methods for making the carbon cryogels, methods for storing a gas using the carbon cryogels, and devices for storing and delivering a gas using the carbon cryogels.

Claims

1. A carbon material comprising a surface area ranging from 1500 m²/g to 3000 m²/g, wherein the carbon material comprises a pore size distribution comprising:

a) pores having a diameter less than 2 nm;

b) pores having a diameter of 3 nm; and

c) pores having a diameter between 7 and 8 nm.

2. A carbon material comprising a gravimetric methane storage capacity ranging from 15% to 20%, a surface area ranging from 2400 m²/g to 2600 m²/g and a total pore volume ranging from 1.0 cm³/g to 1.5 cm³/g.

3. A carbon material comprising a peak pore volume greater than 0.1 cm³/g for pores comprising a diameter less than 2 nm and comprising a peak pore volume greater than 0.1 cm³/g for pores comprising a diameter ranging from 5 nm to 12 nm.

4. The carbon material of claim 3 further comprising a peak pore volume greater than 0.04 cm³/g for pores comprising a diameter ranging from 2 nm to 4 nm.

5. A carbon material comprising a gravimetric methane storage capacity ranging from 0.009 mol/g to 0.013 mol/g at room temperature and 500 psi, a surface area ranging from 1500 m²/g to 2500 m²/g and a total pore volume ranging from 1.2 cm³/g to 1.5 cm³/g.

6. The carbon material of claim 5, wherein the total pore volume ranges from 1.4 cm³/g to 1.5 cm³/g.

7. The carbon material of claim 5, wherein the pore volume ranges from 1.2 cm³/g to 1.4 cm³/g.

8. The carbon material of claim 5 comprising mesopores comprising diameters ranging from 5 nm to 12 nm.

9. The carbon material of claim 5 comprising mesopores comprising diameters ranging from 2 nm to 4 nm.

10. The carbon material of claim 5, wherein the surface area ranges from 1500 m²/g to 2000 m²/g.

11. The carbon material of claim 5, wherein the surface area ranges from 2000 m²/g to 2500 m²2/g.

12. A method for making the carbon material of claim 5, the method comprising:

(a) preparing a sol by mixing resorcinol, formaldehyde, and a catalyst in water;

(b) gelling the sol by heating at a temperature and for a time sufficient to provide a gel;

(c) washing the gel with acid to provide an acid-washed gel comprising an aqueous solvent;

(d) washing the acid-washed gel with a suitable organic solvent to exchange the aqueous solvent for an organic solvent to provide a solvent-exchanged gel;

(e) freeze drying the solvent-exchanged gel; and

(f) pyrolyzing the solvent-exchanged gel to provide a pyrolyzed carbon material.

13. The method of claim 12, wherein the molar ratio of resorcinol to catalyst ranges from 10 to 300.

14. The method of claim 12, wherein the catalyst is sodium carbonate.

15. The method of claim 12, wherein the weight ratio of resorcinol to water ranges from 0.01 to 2.0.

16. The method of claim 12, wherein gelling the sol comprises heating at a temperature and for a period of time sufficient to convert the sol to a crosslinked gel.

17. The method of claim 12, wherein gelling the sol comprises heating at 90°

C. for a time ranging from 1 to 7 days.

18. The method of claim 12, wherein washing the gel with acid comprises washing the gel with aqueous trifluoroacetic acid.

19. The method of claim 12, wherein washing the acid-washed gel comprises washing the gel with t-butanol.

20. The method of claim 12, wherein pyrolyzing the solvent-exchanged gel comprises heating at a temperature and for a period of time sufficient to convert the gel to a pyrolyzed carbon material.

21. The method of claim 12, wherein pyrolyzing the solvent-exchanged gel comprises heating at 1050°

C. for 4 hours under nitrogen.

22. The method of claim 12, further comprising heating the carbon material at a temperature and for a time sufficient to provide an activated carbon material.

23. The method of claim 22, wherein the temperature is 900°

C., and the time ranges from 10 to 120 minutes.

24. The method of claim 22, wherein the carbon material is activated from 5% to 90%.

25. The method of claim 22, wherein heating at a temperature and for a time sufficient to provide an activated carbon material comprises heating at 900°

C. under carbon dioxide.