Flame-synthesis of monolayer and nano-defective graphene
Methods for the production of carbon-based and other nanostructures are provided.
1. A method for synthesizing a graphene structure by reacting an oxidizer and a fuel in a modified multiple, inverse-diffusion flame burner, wherein said modified multiple, inverse-diffusion flame burner comprises delivery tubes for the fuel extending beyond a main burner surface, wherein said graphene structure is monolayer graphene, wherein said method comprises:
a) reducing a metal substrate in said modified, multiple inverse-diffusion flame burner wherein hydrogen (H 2 ) is the only fuel;
b) adding a hydrocarbon precursor through the fuel lines extending beyond the main burner surface of the modified, multiple inverse-diffusion flame burner to synthesize the graphene on said substrate; and
c) annealing the flame-synthesized graphene of step b) by running the modified, multiple inverse-diffusion flame burner wherein hydrogen (H 2 ) is the only fuel and wherein the temperature of the substrate downstream of the modified, multiple inverse-diffusion flame burner is greater than about 850° C.
2. The method of claim 1 , wherein said graphene structure is selected from the group consisting of flakes, films, sheets, plates, and discs.
3. The method of claim 1 , where the modified, multiple, inverse-diffusion-flame burner comprises an array of stabilized flames that form a uniform flat-flame front.
4. The method of claim 1 , wherein the oxidizer is air, O 2 , or an oxidizing agent.
5. The method of claim 1 , wherein the graphene structure is synthesized on a metal substrate.
6. The method of claim 5 , wherein the metal substrate is copper.
7. The method of claim 6 , wherein the substrate temperature downstream of the modified, multiple inverse-diffusion flame burner in step c) is about 950° C. to about 1050° C.
8. The method of claim 7 , wherein the substrate temperature downstream of the modified, multiple inverse-diffusion flame burner in step c) is about 1000° C.
9. The method of claim 1 , where the fuel contains at least one additive, thereby forming doped graphene structures.
10. The method of claim 9 , wherein the additive is a nitrogen species or a boron species.
11. The method of claim 1 , further comprising assaying the graphene structure by Raman spectra.
12. The method of claim 1 , further comprising transferring the graphene structure to a substrate after synthesis.
13. The method of claim 1 , further comprising doping the graphene structure with ions.
14. The method of claim 13 , wherein said graphene structure is doped with ions in vacant atomic sites.
15. The method of claim 13 , wherein said ions are metal ions.
16. The method of claim 1 , wherein the substrate temperature downstream of the modified, multiple inverse-diffusion flame burner in step c) is about 950° C. to about 1050° C.
17. The method of claim 16 , wherein the substrate temperature downstream of the modified, multiple inverse-diffusion flame burner in step c) is about 1000° C.
18. A method for synthesizing a nano-defective graphene structure by reacting an oxidizer and a fuel in a modified multiple, inverse-diffusion flame burner, wherein said modified multiple, inverse-diffusion flame burner comprises delivery tubes for the fuel extending beyond a main burner surface, wherein said method comprises:
a) reducing a metal substrate in said modified, multiple inverse-diffusion flame burner wherein hydrogen (H 2 ) is the only fuel;
b) adding a hydrocarbon precursor through the fuel lines extending beyond the main burner surface of the modified, multiple inverse-diffusion flame burner to synthesize the graphene on said substrate; and, optionally,
c) annealing the flame-synthesized graphene of step b) by running the modified, multiple inverse-diffusion flame burner wherein hydrogen (H 2 ) is the only fuel,
wherein the flame-synthesized graphene of step b) has an I D /I G ratio of about 0.6 or higher prior to step c).
19. The method of claim 18 , wherein said method comprises annealing the flame-synthesized graphene of step b) by running the modified, multiple inverse-diffusion flame burner wherein hydrogen (H 2 ) is the only fuel.
20. The method of claim 18 , wherein said metal substrate is less than 99.9% pure.
21. The method of claim 18 , wherein said graphene structure is selected from the group consisting of flakes, films, sheets, plates, and discs.
22. The method of claim 18 , where the modified, multiple, inverse-diffusion-flame burner comprises an array of stabilized flames that form radially uniform temperature and species distribution downstream.
23. The method of claim 18 , wherein the oxidizer is air, O 2 , or an oxidizing agent.
24. The method of claim 18 , wherein said graphene structure is a monolayer.
25. The method of claim 18 , wherein the metal substrate is copper.
26. The method of claim 18 , where the fuel contains at least one additive, thereby forming doped graphene structures.
27. The method of claim 26 , wherein the additive is a nitrogen species or a boron species.
28. The method of claim 18 , further comprising assaying the graphene structure by Raman spectra.
29. The method of claim 18 , further comprising doping the graphene structure with ions.
30. The method of claim 29 , wherein said graphene structure is doped with ions in vacant atomic sites.
31. The method of claim 29 , wherein said ions are metal ions.