Porous polymeric materials for hydrogen storage
Porous polymers, tribenzohexazatriphenylene, poly-9,9′-spirobifluorene, poly-tetraphenyl methane and their derivatives for storage of H 2 prepared through a chemical synthesis method. The porous polymers have high specific surface area and narrow pore size distribution. Hydrogen uptake measurements conducted for these polymers determined a higher hydrogen storage capacity at the ambient temperature over that of the benchmark materials. The method of preparing such polymers, includes oxidatively activating solids by CO 2 /steam oxidation and supercritical water treatment.
1. A hydrogen storage system comprising:
a porous polymer comprised of tribenzohexazatriphenylene having repeating units depicted by:
wherein the porous polymer having a capacity between 0.004 and 0.008 kg H 2 /kg —ads gravimetric capacity
measured at an ambient temperature of about 25 C.
2. The hydrogen storage system as defined in claim 1 , wherein the porous polymer is formed by reacting hexaketocyclohexane octahydrate and 3,3′-diaminobenzidine.
3. The hydrogen storage system as defined in claim 2 , wherein the ratio of hexaketocyclohexane octahydrate and 3,3′-diaminobenzidine is selected from the group consisting of about 0.5 to 2 and about 2 to 1.
4. The hydrogen storage system as defined in claim 1 , wherein the porous polymer consists essentially of tribenzohexazatriphenylene.
5. The hydrogen storage system as defined in claim 1 , wherein the porous polymer has a pore diameter distribution between about 0.3-1.0 nm.
6. The hydrogen storage systems are defined in claim 1 , wherein the porous polymer comprises an extended π-electron configuration.
7. A method of creating a porous polymer, the method comprising:
reacting hexaketocyclohexane octahydrate and 3,3′-diaminobenzidine in a ratio of from about 0.5 to 2 to about 2 to 1 via steps of polymer condensation.
8. The method as defined in claim 7 , further including having a reaction temperature in the range of about 50° C. to 200 C and a reaction time of about 2 hours to 24 hours.
9. The method as defined in claim 7 further including,
precipitating a solid from the reaction;
filtering the solid;
washing the filtered solid with an organic solvent; and
drying the washed solid.
10. The method as defined in claim 7 , further including oxidatively activating the washed solid with CO 2 /steam oxidation or supercritical water treatments.
11. The method as defined in claim 9 further including the steps of:
placing the washed solid in a packed bed configuration inside of a reactor;
raising the temperature of the reactor to between about 300 C and 750 C;
feeding CO 2 or steam into the reactor; and
oxidizing the washed solid with CO 2 or steam to form pores in the washed solid.
12. The method as defined in claim 11 , wherein the washed solid is reacted in the reactor for about 30 min to 4 hours.
13. The method as defined in claim 10 , wherein the supercritical water treatment comprises:
placing the washed solid in a supercritical water reactor in a mixture with high purity water;
raising the temperature of the reactor to above the triple critical point of supercritical water; and
forming pores in the washed solid via partial oxidation.
14. The method as defined in claim 13 , wherein the temperature of the reactor is between about 375 C and about 500 C and the reaction time between about 30 minutes and about 4 hours.
15. The method as defined in claim 7 , wherein the porous polymer has a polymer backbone with functional groups comprised of dipole moment components.
16. The method as defined in claim 15 , wherein the functional groups consist essentially of carbonyl, carboxyl and aldehyde groups.
17. A hydrogen storage system comprising:
a porous polymer comprised of tribenzohexazatriphenylene wherein:
the porous polymer having a capacity of about 0.017 kg H 2 /kg —ads gravimetric capacity and a volumetric capacity of about 0.016 kg H 2 /L at −196 C and a volumetric capacity of 0.007 kg H 2 /L measured at an ambient temperature of about 25 C, and the porous polymer is formed by reacting hexaketocyclohexane octahydrate and 3,3′-diaminobenzidine.
18. The hydrogen storage system as defined in claim 17 , wherein the ratio of hexaketocyclohexane octahydrate and 3,3′-diaminobenzidine is selected from the group consisting of about 0.5 to 2 to about 2 to 1.
19. The hydrogen storage system as defined in claim 17 , wherein the porous polymer consists essentially of tribenzohexazatriphenylene.
20. The hydrogen storage system as defined in claim 1 , wherein the porous polymer has BET surface area of about 120 m2/g.