REDUCTIVE-EXPANSION SYNTHESIS OF GRAPHENE

Claudia Catalina Luhrs

Patent

Atlas literature

Patent

US 8,894,886

REDUCTIVE-EXPANSION SYNTHESIS OF GRAPHENE

Claudia Catalina Luhrs

Claims

Claims define the patent's legal scope. Independent claims stand alone; dependent claims (nested) narrow them. Click a claim to expand its dependents.

8 independent · 16 dependent

1
Independentgraphite oxidegraphite oxide(NH₂)2COSC(NH₂)2graphene-based product
A method of forming a graphene-based product comprising: forming a solid phase, physical mixture compris in g one or more graphite-based precursors and one or more solid phase reduction-expansion chemical agents selected from the group consisting of urea [(NH₂)2C O] and thiourea [SC(NH₂)2], wherein each of the one or more graphite-based precursors comprises one or more of a graphite oxide, an expandable graphite, and a combination thereof; and heating the physical mixture in an inert atmosphere at a temperature suﬃcient to thermally decompose the solid phase reduction-expansion chemical agent to produce a reducing gas and form a graphene-based product compris in g one or more of a single graphene sheet, a stack of two or more single graphene sheets, entangled single graphene sheets, and combinations thereof.
1. 2
  Dependent← claim 1
  The method of claim 1, wherein the physical mixture comprises a molar ratio of the one or more graphite-based precursors to the chemical agent, wherein the molar ratio ranges from about 1:100 to about 100: 1.
2. 3
  Dependent← claim 1
  The method of claim 1, wherein the step of forming a physical mixture comprises: -2-AMENDMENT ATTORNEY DOCKET N o.: 0023.0116 APPLICATION N o.: 13/040,976 mixing the one or more graphite-based precursors with the solid phase reduction- expansion chemical agent as a solid mixture.
3. 4
  Dependent← claim 1
  The method of claim 1, wherein the step of forming a physical mixture comprises: forming a chemical agent-containing solution by dissolving the solid phase reduction- expansion chemical agent in a solvent, mixing the chemical agent-containing solution with the one or more graphite-based precursors, and drying the mixture containing the chemical agent and the one or more graphite-based precursors during or prior to the heating step.
4. 5
  Dependent← claim 1
  The method of claim 1, wherein the temperature ranges from about 300 o C to about 800 o C, the temperature being suﬃcient to result in a reductive-expansion process of the one or more graphite-based precursors. previously presented
5. 8
  Dependent← claim 1
  The method of claim 1, wherein the step of heating the physical mixture comprises placing the physical mixture in a pre-heated device at a heating temperature. -3- AMENDMENT ATTORNEY DOCKET N o.: 0023.0116 APPLICATION N o.: 13/040,976
6. 9
  Dependent← claim 1
  The method of claim 1, wherein the step of heating the physical mixture comprises placing the physical mixture in an oven, wherein the oven is then heated from room temperature to a heating temperature.
7. 10
  Dependent← claim 1
  The method of claim 1, wherein the inert atmosphere is provided by a chemically inert gas comprising N2, Ar, He, or a combination thereof
8. 11
  Dependent← claim 1graphene-based product
  The method of claim 1, further comprising: cooling the graphene-based product under an inert atmosphere following the heating step, and collecting the graphene-based product.
9. 12
  Dependent← claim 1graphene-based product
  The method of claim 1, wherein the graphene-based product comprises a nano-sheet.
10. 13
  Dependent← claim 1graphene-based product
  The method of claim 1, wherein the graphene-based product has a carbon content of at least about 90 % by weight. original
11. 15
  Dependent← claim 1graphene-based product
  The method of claim 1, wherein the graphene-based product is formed with more than about
6
Independent
CANCELLED canceled
7
Independent
CANCELLED canceled
14
Independent
CANCELLED. canceled
16
Independent
canceled
17
Independentgraphene-based product
The method of claim [[16]] 1, wherein the graphene-based product comprises about 30 % or less impurity atomic species by weight of the total graphene-based product.
18
Independentgraphite oxide(NH₂)2COgraphene-based product
A method of forming a graphene-based product comprising: forming a physical mixture by physically mixing graphite oxide with a reductive- expansion agent comprising urea; heating the physical mixture in an inert atmosphere at a heating temperature to form a free-standing graphene-based product, wherein the heating temperature is at or above a decomposition temperature of the reductive-expansion agent; and cooling the free-standing graphene-based product, wherein the graphene-based product comprises one or more of a single graphene sheet, a stack of two or more single graphene sheets, and entangled single graphene sheets.
1. 19
  Dependent← claim 18
  The method of claim 18, wherein the step of heating the physical mixture comprises placing the physical mixture in a device pre-heated at a heating temperature of about 600 ' C or higher.
2. 20
  Dependent← claim 18
  The method of claim 18, wherein the step of heating the physical mixture comprises placing the physical mixture in a device, wherein the device is then heated from room temperature to the heating temperature of about 600 ' C or higher for about 30 minutes or less. -5- AMENDMENT ATTORNEY DOCKET N o.: 0023.0116 APPLICATION N o.: 13/040,976
3. 21
  Dependent← claim 18
  The method of claim 18, wherein the reduction-expansion agent is a solid, and the heating temperature ranges from about 300 o C to about 800 oC.
4. 24
  Dependent← claim 18graphite oxide(NH₂)2CO
  The method of claim 18, wherein the physical mixture comprises a molar ratio of the graphite oxide to the urea, wherein the molar ratio ranges from 1:2 to 1:10. -6-
22
Independentgraphite oxide(NH₂)2COfree-standing graphene
A method of forming free standing graphene comprising: forming a physical mixture by physically mixing graphite oxide with a reductive- expansion agent comprising urea; heating the physical mixture in an inert atmosphere at a heating temperature to form free standing graphene, wherein the heating temperature is at or above a decomposition temperature of the reductive-expansion agent; and cooling the free-standing graphene, wherein the free standing graphene comprises graphene sheets.
1. 23
  Dependent← claim 22
  The method of claim 22, wherein heating the physical mixture comprises heating at a temperature of 600 ' C or higher.

Materials

Materials described outside the worked examples.

graphite oxide

Graphite-Based Precursor

urea

(NH₂)2CO

Process steps

Additional fabrication and treatment steps described in the patent.

Thermal Reduction Expansion

Step 1

Temperature

300, 800°C

Ambient

inert atmosphere (N2, Ar, He, or combination)

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