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Method for preparing ultra-dispersible graphene through liquid nitrogen cold quenching

A graphene and ultra-dispersion technology, which is applied in the field of macro-preparation of ultra-dispersed graphene, can solve the problems of increasing the production cycle of graphene and affecting the quality of prepared graphene, shortening the preparation cycle and shortening the cycle of in-situ freeze-drying , low cost effect

Active Publication Date: 2015-06-10
LANZHOU INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, this method also has defects. Since the surfactant is added in this process, the surface activity needs to be removed in the subsequent preparation process, which undoubtedly increases the preparation cycle of graphene, and if the surfactant does not Complete removal will affect the quality of prepared graphene

Method used

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  • Method for preparing ultra-dispersible graphene through liquid nitrogen cold quenching
  • Method for preparing ultra-dispersible graphene through liquid nitrogen cold quenching

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Experimental program
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Effect test

Embodiment 1

[0021] Graphite oxide was prepared by the modified Hummers method using 32 mesh natural flake graphite. Graphite oxide was prepared from flake graphite at an oxidation temperature of 35 °C and an oxidation time of 2 h. The graphite oxide was dispersed in water, the ultrasonic time was 10 min, and the ultrasonic power was 600 W, and then the visible particles were removed by centrifugation at 3000 rpm , to obtain a graphene oxide solution.

[0022] The graphene oxide solution with a concentration of 0.5 mg / ml was heated to 40 °C and quenched directly in liquid nitrogen until the solution was completely frozen, and then it was freeze-dried in situ. After drying, the ultra-dispersed graphene oxide material was obtained, and then it was reduced under the protection of Ar gas at 900 °C to obtain ultra-dispersed graphene.

[0023] Electron microscope observation results show that: under such conditions, more than 90% of the graphene sheets in the graphene powder are in a few-layer ...

Embodiment 2

[0025] The preparation method of graphene oxide solution is the same as embodiment 1.

[0026] The graphene oxide solution with a concentration of 2 mg / ml was heated to 40 °C and quenched directly in liquid nitrogen until the solution was completely frozen, and then it was freeze-dried in situ. After drying, the ultra-dispersed graphene oxide material was obtained, and then it was reduced under the protection of Ar gas at 900 °C to obtain ultra-dispersed graphene.

[0027] Electron microscope observation results show that: under such conditions, more than 85% of the graphene sheets in the graphene powder are in a few-layer dispersed state.

Embodiment 3

[0029] The preparation method of graphene oxide solution is the same as embodiment 1.

[0030] The graphene oxide solution with a concentration of 6 mg / ml was heated to 40 °C and quenched directly in liquid nitrogen until the solution was completely frozen, and then it was freeze-dried in situ. After drying, the ultra-dispersed graphene oxide material was obtained, and then it was reduced under the protection of Ar gas at 900 °C to obtain ultra-dispersed graphene.

[0031] Electron microscope observation results show that: under such conditions, more than 80% of the graphene sheets in the graphene powder are in a few-layer dispersed state. like figure 2 As shown, the 6 mg / ml graphene oxide solution was directly put into liquid nitrogen and quenched after being heated to 40 °C. It can be seen from the photos of the scanning electron microscope that the high-concentration graphene oxide solution was quenched, and the graphene sheets Layers can also remain thin and hyperdisper...

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Abstract

The invention discloses a method for preparing ultra-dispersible graphene through liquid nitrogen cold quenching. Oxidized graphene with different sizes is prepared by adopting a chemical method, an oxidized graphene solution is heated and then cold-quenched in liquid nitrogen, and thus ultra-dispersible oxidized graphene is prepared; and then, the ultra-dispersible oxidized graphene is reduced by a heating or chemical reduction way, to obtain the ultra-dispersible graphene. The method has the advantages of low cost and simple flow path, can shorten the preparation period (mainly shortens the period of sample freeze drying), and is suitable for mass preparation of the ultra-dispersive graphene.

Description

technical field [0001] The invention relates to a graphene preparation technology, in particular to a method for preparing ultra-dispersed graphene by cooling a graphene oxide solution under a liquid nitrogen environment, and is suitable for macro-preparation of ultra-dispersed graphene. Background technique [0002] Graphene is currently the most popular new type of nano-carbon material, which has many excellent properties, such as: unique quantum Hall effect, high Young's modulus (~1,100 GPa), high elastic modulus (130 GPa), good thermal conductivity (~5,000 Wm -1 K -1 ), high electron mobility (200,000 cm 2 V -1 the s -1 ), high specific surface area (theoretical calculation value, 2,630 m 2 g -1 ), good light transmission, easy to functionalize, etc. These excellent properties also make graphene have broad application prospects in many fields such as nanoelectronic devices, transparent conductive films, electrode materials, and composite materials ( Nat. Mater. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B31/04
Inventor 阎兴斌赵金平薛群基
Owner LANZHOU INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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