Carbon allotropes
A nanoparticle or agglomerate which contains connected multi-walled spherical fullerenes coated in layers of graphite. In different embodiments, the nanoparticles and agglomerates have different combinations of: a high mass fraction compared to other carbon allotropes present, a low concentration of defects, a low concentration of elemental impurities, a high Brunauer, Emmett and Teller (BET) specific surface area, and/or a high electrical conductivity. Methods are provided to produce the nanoparticles and agglomerates at a high production rate without using catalysts.
1. A carbon aggregate comprising:
at least two connected multi-walled spherical fullerenes; and
layers of graphene coating the connected multi-walled spherical fullerenes.
2. The carbon aggregate of claim 1 , wherein:
a ratio of carbon to other elements, except H, in the carbon aggregate is greater than 99.9%.
3. The carbon aggregate of claim 1 , wherein:
a Raman spectrum of the carbon aggregate using 532 nm incident light has a first Raman peak at approximately 1350 cm −1 and a second Raman peak at approximately 1580 cm −1 ; and
a ratio of an intensity of the first Raman peak to an intensity of the second Raman peak is from 0.9 to 1.1.
4. The carbon aggregate of claim 1 , wherein:
the multi-walled spherical fullerenes do not comprise a seed particle or a void at the center of the multi-walled spherical fullerenes.
5. The carbon aggregate of claim 1 , wherein:
a diameter across the carbon aggregate is from 10 microns to 500 microns.
6. The carbon aggregate of claim 1 , wherein:
the ratio of graphene to multi-walled spherical fullerenes in the carbon aggregate is from 10% to 80%.
7. The carbon aggregate of claim 1 , wherein:
a Brunauer, Emmett and Teller (BET) specific surface area of the carbon aggregate is from 10 m 2 /g to 200 m 2 /g.
8. The carbon aggregate of claim 1 , wherein:
a plurality of the carbon aggregates are compressed into a pellet, and the pellet has an electrical conductivity from 500 S/m to 20000 S/m.
9. A mixture comprising a liquid and a plurality of the carbon aggregates of claim 1 .
10. An ink comprising a plurality of the carbon aggregates of claim 1 , wherein the ink is a conductive ink.
11. A method comprising:
flowing a hydrocarbon feedstock process gas into a reaction zone;
thermally cracking molecules of the feedstock process gas in the reaction zone;
reacting the thermally cracked molecules to form carbon aggregates, each comprising at least two connected multi-walled spherical fullerenes coated in layers of graphene; and
collecting the carbon aggregates.
12. The method of claim 11 , wherein:
a ratio of carbon to other elements, except H, in the carbon aggregates is greater than 99.9%.
13. The method of claim 11 , wherein:
a Raman spectrum of the carbon aggregates using 532 nm incident light has a first Raman peak at about 1350 cm −1 and a second Raman peak at about 1580 cm −1 , and
a ratio of an intensity of the first Raman peak to an intensity of the second Raman peak is from 0.9 to 1.1.
14. The method of claim 11 , wherein:
the multi-walled spherical fullerenes do not comprise a seed particle or a void at the center of the multi-walled spherical fullerenes.
15. The method of claim 11 , wherein:
an average diameter across the carbon aggregates is from 10 microns to 500 microns.
16. The method of claim 11 , wherein:
a ratio of graphene to multi-walled spherical fullerenes is from 10% to 80%.
17. The method of claim 11 , wherein:
a Brunauer, Emmett and Teller (BET) specific surface area of the carbon aggregates is from 10 m 2 /g to 200 m 2 /g.
18. The method of claim 11 , further comprising:
compressing the carbon aggregates into a pellet, wherein the pellet has an electrical conductivity from 500 S/m to 20000 S/m.
19. The method of claim 11 , further comprising:
the flow rate of the hydrocarbon feedstock process gas is from 1 slm to 10 slm; and
the carbon aggregates are formed at a production rate from 10 g/hr to 200 g/hr.
20. The method of claim 11 , further comprising:
post-processing the collected carbon aggregates using a method selected from group consisting of milling, grinding, exfoliating, annealing, sintering, steaming, filtering, lypolizing, doping, and adding elements.