Preparation method of graphene

A technology of graphene and graphene quantum dots, applied in the direction of graphene, nano-carbon, etc., can solve the problems of impurity removal, low peeling yield, difficult to remove residual solvents, etc., and achieve the effect of simple process and good quality

Active Publication Date: 2014-07-23
SHANGHAI INST OF MICROSYSTEM & INFORMATION TECH CHINESE ACAD OF SCI
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, studies have shown that the yield of graphene prepared by the solvent stripping method has a great relationship with the solvent. Generally, N-2-methylpyrrolidone (NMP), N,N-dimethylformamide (DMF) and other high-boiling point solvents are selected. Organic solvents, there is a problem that it is difficult to remove residual solvents
In addition, even if a suitable solvent is selected, the yield of simple solvent stripping is generally very low, further improving the stripping yield requires adding inorganic salts, alkalis or surfactants, etc., and there is also the problem of impurity removal.

Method used

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Embodiment 1

[0015] Example 1: Weigh 100mg of natural graphite, 10mg of graphene oxidized by concentrated sulfuric acid, concentrated nitric acid or their mixed acid to obtain graphene quantum dot powder, wherein the carbon and oxygen atomic content ratio is 20:1, and the average lateral dimension About 10nm. The above two powders were added to 50 mL of deionized water to prepare a mixed suspension of graphite and graphene quantum dots. Ultrasonic treatment of the suspension with a probe to obtain a suspension of graphene, graphene quantum dots and graphite. Centrifuge the above suspension, take the graphene / graphene quantum dot mixed solution stably dispersed in the upper layer, filter and separate the graphene quantum dot and graphene, and dry the filter cake to obtain 12.5 mg of graphene powder. figure 2 It is a high-resolution transmission electron microscope picture of the obtained graphene, as can be seen from the figure, the number of atomic layers of the graphene is less than 10 ...

Embodiment 2

[0016] Example 2: Weigh 100 mg of natural graphite, 20 mg of graphene oxidized by concentrated sulfuric acid, concentrated nitric acid or their mixed acid to obtain graphene quantum dot powder, wherein the carbon and oxygen atomic content ratio is 11:1, and the average lateral dimension About 20nm. The above two powders were added into 100mL ethanol to prepare a mixed suspension of graphite and graphene quantum dots. Ultrasonic treatment of the suspension with a probe to obtain a suspension of graphene, graphene quantum dots and graphite. Centrifuge the above suspension, take the graphene / graphene quantum dot mixed solution stably dispersed in the upper layer, filter and separate the graphene quantum dot and graphene, and dry the filter cake to obtain 21 mg of graphene powder.

Embodiment 3

[0017] Example 3: Weigh 300mg of natural graphite, 30mg of graphene is oxidized and cut by concentrated sulfuric acid and concentrated nitric acid mixed acid to obtain graphene quantum dot powder, wherein the carbon and oxygen atomic content ratio is 4:1, and the average lateral size is about 20nm . The above two powders were added to 50mL of N-2-methylpyrrolidone (NMP) to prepare a mixed suspension of graphite and graphene quantum dots. The above-mentioned suspension is added to a ball mill jar for high-speed ball milling to obtain a suspension of graphene, graphene quantum dots and graphite. Put the suspension above still, take the graphene / graphene quantum dot mixed solution stably dispersed in the upper layer, filter and separate the graphene quantum dot and graphene, and dry the filter cake to obtain 162 mg of graphene powder.

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Abstract

The invention discloses a preparation method of graphene, which is characterized in that natural graphite used as a raw material is subjected to mechanical stripping under the auxiliary action of graphene quantum dots by using a polar solvent as a dispersion medium to prepare the high-quality graphene. The stripping of the natural graphite and dispersion of the graphene nanosheets in the polar solvent are promoted by utilizing the favorable dispersivity of the graphene quantum dots in the polar solvent and the strong non-covalent bond combination between the graphene quantum dots and graphene / graphene laminae, thereby obtaining the high-quality graphene. According to the invention, the graphene powder is directly obtained from the natural graphite under the condition of not introducing any surfactant, inorganic salt, organic salt or any other impurity. Compared with the existing methods, the method is simple in technique, and can be perform in multiple polar solvents; the maximum yield of the obtained graphene can reach 50%, and the quality is good; the graphene quantum dots used for auxiliary stripping can be recycled; and thus, the method is very suitable for mass preparation of graphene.

Description

technical field [0001] The invention relates to a preparation method of graphene, which belongs to the technical field of new nanometer materials. Background technique [0002] Graphene is a nano-carbon material with a hexagonal lattice honeycomb structure formed by sp2 hybridization of a single layer of carbon atoms, which belongs to a new type of two-dimensional crystal material. Graphene has good electrical conductivity, thermal conductivity, optical transparency, and special mechanical and electronic properties. It has good application prospects in energy storage, transparent conductive devices, composite materials, and optoelectronic devices. Therefore, graphene has become a research hotspot in many disciplines such as materials science, physics and chemistry. [0003] The preparation methods of graphene mainly include mechanical exfoliation method, chemical vapor deposition method, oxidation intercalation re-reduction method and liquid phase exfoliation method. Among...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B31/04C01B32/186
Inventor 何朋田素云孙静丁古巧谢晓明江绵恒
Owner SHANGHAI INST OF MICROSYSTEM & INFORMATION TECH CHINESE ACAD OF SCI
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