Activated carbon cryogels and related methods
View Patent ↗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.
1. A carbon material comprising a surface area ranging from 1500 m 2 /g to 3000 m 2 /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 m 2 /g to 2600 m 2 /g and a total pore volume ranging from 1.0 cm 3 /g to 1.5 cm 3 /g.
3. A carbon material comprising a peak pore volume greater than 0.1 cm 3 /g for pores comprising a diameter less than 2 nm and comprising a peak pore volume greater than 0.1 cm 3 /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 cm 3 /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 m 2 /g to 2500 m 2 /g and a total pore volume ranging from 1.2 cm 3 /g to 1.5 cm 3 /g.
6. The carbon material of claim 5 , wherein the total pore volume ranges from 1.4 cm 3 /g to 1.5 cm 3 /g.
7. The carbon material of claim 5 , wherein the pore volume ranges from 1.2 cm 3 /g to 1.4 cm 3 /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 m 2 /g to 2000 m 2 /g.
11. The carbon material of claim 5 , wherein the surface area ranges from 2000 m 2 /g to 2500 m 2 2 /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.