Preparation method of high purity and high concentration graphene suspension

A graphene suspension, high-concentration technology, applied in the preparation of high-concentration graphene suspension, high-purity field, can solve the problem of low concentration, difficult to prepare high-conductivity graphene suspension, and limit the application of graphene

Inactive Publication Date: 2010-09-15
XI AN JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Oxidation-reduction method is one of the important methods to prepare graphene. However, in the process of converting graphene oxide to graphene by reducing agent, it is often accompanied by the agglomeration of graphene, and it is difficult to obtain a stable and dispersed high-concentration graphene suspension.
In the early days, adding surfactants, polymers or other modifiers during the reduction process could obtain a stable graphene suspension, but the impurities introduced by these methods reduced the purity of graphene, resulting in lower electrical conductivity and poor thermal conductivity of graphene. , limiting the application of grap

Method used

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  • Preparation method of high purity and high concentration graphene suspension
  • Preparation method of high purity and high concentration graphene suspension

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] 1) Preparation of graphite oxide:

[0026] Take 2g of natural flake graphite and 25mL of sulfuric acid with a concentration of 98% and mix evenly, then add 1g of sodium nitrate and 2g of potassium permanganate and react in a water bath at -2°C for 4h, then react at 40°C for 0.5h, and then add 50mL of React with distilled water at 60°C for 12 hours, then dilute with 0.1L distilled water to terminate the oxidation reaction, then add hydrogen peroxide to reduce the residual potassium permanganate, filter and wash with distilled water until neutral, and vacuum dry to obtain graphite oxide solid;

[0027] 2) Preparation of graphene oxide suspension:

[0028] Add graphite oxide solid into water to make 1.0mg·mL -1 Graphite oxide suspension, the graphite oxide suspension was dispersed for 2h under the action of ultrasonic waves to obtain uniform and stable graphene oxide (see figure 2 a) suspension;

[0029] 3) preparation of graphene suspension:

[0030] The graphene oxi...

Embodiment 2

[0032] 1) Preparation of graphite oxide:

[0033] Mix 50g of natural flake graphite with 400mL of 90% sulfuric acid and 200ml of 67% nitric acid, then add 10g of sodium nitrate, 30g of potassium perchlorate and 35g of potassium chlorate and react in a water bath at -1°C for 3 hours, and then React for 24 hours, then add 1150mL of distilled water and react at 80°C for 5 hours, then dilute with 3L of distilled water to terminate the oxidation reaction, filter and wash with distilled water until neutral, and dry in vacuum to obtain graphite oxide solid;

[0034] 2) Preparation of graphene oxide suspension:

[0035] Add graphite oxide solid into ethanol to make 1.1mg·mL -1 Graphite oxide suspension, the graphite oxide suspension was dispersed for 3h under the action of ultrasonic waves to obtain a uniform and stable graphene oxide suspension;

[0036] 3) Preparation of graphene suspension:

[0037]The graphene oxide suspension is under the protection of nitrogen, and the reacti...

Embodiment 3

[0039] 1) Preparation of graphite oxide:

[0040] Take 15g of natural flake graphite and 100mL of sulfuric acid with a concentration of 93% and mix evenly, then add 20g of potassium perchlorate, react in a water bath at 2°C for 1h, then react at 30°C for 12h, then add 200mL of distilled water and react at 100°C for 0.5 h, then dilute with 0.5L distilled water to terminate the oxidation reaction, filter and wash with distilled water to neutrality, and dry in vacuo to obtain graphite oxide solid;

[0041] 2) Preparation of graphene oxide suspension:

[0042] Add graphite oxide solid to nitrogen methyl pyrrolidone to make 2.0 mg·mL -1 Graphite oxide suspension, the graphite oxide suspension was dispersed for 5h under the action of ultrasonic waves to obtain a uniform and stable graphene oxide suspension;

[0043] 3) preparation of graphene suspension:

[0044] Put the graphene oxide suspension under nitrogen protection, control the reaction temperature at 70°C, add ethylenedia...

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Abstract

The invention relates to a preparation method of a high purity and high concentration graphene suspension, which comprises the following steps of: reacting natural crystalline flake graphite with a strong oxidizer to obtain graphite oxide; spreading the graphite oxide into a dispersing agent, and obtaining a graphene oxide suspension by ultrasonic dispersion; mixing the graphene oxide suspension with hydrazine hydrate under the protection of nitrogen and reacting at constant temperature under ultrasonic radiation to prepare stable graphene suspension. Compared with the traditional method for preparing the graphene suspension, the method introduces ultrasonic in the reduction process of the graphite oxide. The invention has the following advantages that the prepared graphene suspension has high concentration (higher than 1 mg.mL<-1>), high purity (without influence of surface active agents and other impurities), high dispersionstability (time for stable dispersion is more than 60 days) and the like; the graphene prepared by the method has high electrical conductivity (high than 700 S.m<-1>), less number of layers, is simple and easy to implement, and is very suitable for large scale production in industy.

Description

technical field [0001] The invention belongs to the field of material preparation, in particular to a method for preparing a high-purity, high-concentration graphene suspension. Background technique [0002] In recent years, ultrasonic waves have been widely used in the preparation of nanomaterials, which can produce strong cavitation and vibration effects when passing through liquid media, thereby providing unique reaction sites for chemical reactions, and have developed into a universal nanomaterial Preparation. The high temperature generated by ultrasonic cavitation and a large number of tiny bubbles generated on the solid surface reduce the specific surface free energy of tiny grains and inhibit the aggregation and growth of crystal nuclei; the strong shock waves and micro jets generated by ultrasonic cavitation The shearing and crushing of particles effectively reduces the van der Waals force between tiny particles, thereby effectively preventing the agglomeration of t...

Claims

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Application Information

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IPC IPC(8): C01B31/04
Inventor 井新利何伟张伟娜
Owner XI AN JIAOTONG UNIV
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