Method for preparing graphene by low-temperature chemical reduction method

A technology of low-temperature chemistry and graphene, which is applied in the field of low-temperature chemical reduction to prepare graphene and low-temperature catalytic reduction of graphite nanomaterials. It can solve the problems of incomplete reduction, complicated process, and harsh conditions, and achieve a mild and controllable reduction reaction. , wide application prospects, mild and controllable effect

Active Publication Date: 2011-11-30
TSINGHUA UNIV
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AI Technical Summary

Problems solved by technology

Various methods have their advantages and disadvantages: the mechanical exfoliation method is not suitable for large-scale industrial preparation of graphene due to the limitations of the exfoliation method; the chemical vapor deposition method and the epitaxial growth method have complex processes, harsh conditions, low yield, Disadvantages such as high cost limit its large-scale industrial production and application of graphene
While the existing reducing agent NaBH 4 , various alkoxides and N 2 h 4 And its derivatives still have problems such as incomplete reduction of oxidized functional groups and low conductivity of products, all of which have problems of incomplete reduction
In addition, the organic reducing agent hydrazine and its derivatives are highly toxic and may cause environmental pollution
However, NaH and high-concentration HI are used as reducing agents, although the reducing effect is better, but the reactivity is too high, resulting in too severe reduction reaction and difficult to control.

Method used

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  • Method for preparing graphene by low-temperature chemical reduction method

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preparation example Construction

[0025] The preparation method of graphene oxide used in the example: mix 3g of graphite powder, 3g of sodium nitrate and 138ml of concentrated sulfuric acid in an ice bath; then slowly add 18g of potassium permanganate, magnetically stir and mix, and then heat in a 35°C water bath for 1h; Then add 240ml of deionized water and heat at 90°C for 0.5h. After the heating, add 600ml of deionized water and 18ml of hydrogen peroxide.

[0026] The graphene oxide obtained after oxidation can be ultrasonically dispersed, then diluted according to a certain ratio, and finally the diluted liquid is centrifuged, and the upper layer suspension is taken, and a graphene oxide film of a certain thickness is prepared by suction filtration.

[0027] After the prepared graphene film is dried, measure the film thickness of the graphene film with a step meter, and measure its electrical conductivity with a four-probe method.

Embodiment 1

[0029] After centrifugation, 40ml of graphene oxide (GO) supernatant suspension (GO concentration 0.2mg / ml, solvent is ethanol) was suction-filtered to form a film, and dried for later use.

[0030] Dissolve 7.62g of iodine and 1.5g of aluminum in 100ml of ethanol, heat and stir to prepare aluminum iodide (the concentration of aluminum iodide is 0.2mol / L, wherein the aluminum is excessive). Then the dried graphene oxide (GO) film was put into aluminum iodide solution and reduced at 80 °C for 1 h under magnetic stirring.

[0031] The test result is: the conductivity of the graphene film is 5230S / m.

[0032] Using aluminum iodide as a reducing agent, changing the concentration of the reducing agent, and keeping other conditions constant, the electrical conductivity of the obtained graphene is shown in the following table:

[0033]

Embodiment 2

[0035] Dissolve 7.62g of iodine and 1.5g of aluminum in 100ml of N,N-dimethylformamide (DMF), heat and stir to prepare aluminum iodide (the concentration of aluminum iodide is 0.2mol / L, wherein the aluminum is excessive). Then the dried graphene oxide (GO) film was put into aluminum iodide solution and reduced at 140 °C for 1 h under magnetic stirring.

[0036] The test result is: the conductivity of the graphene film is 7110S / m.

[0037] Using aluminum iodide as a reducing agent, changing the solvent type, reduction temperature and reduction time, and under the premise of other conditions unchanged, the electrical conductivity of the obtained graphene is shown in the following table:

[0038]

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Abstract

The invention discloses a method for preparing graphene by a low-temperature chemical reduction method, which belongs to the technical field of chemical composition of graphene. In the method, graphene oxide prepared by chemical oxidation is used as a raw material. The method comprises the reduction reaction step of reducing the graphene oxide into graphene; in the reduction reaction step, aluminum iodide is used as a reducer; the reduction of the graphene oxide is realized by controlling the concentration of the reducer and a solvent type at 60 DEG C to 180 DEG C; oxygen-containing functional groups (epoxy group, hydroxyl group, carboxyl group and carbonyl group) on the graphene oxide are removed; the electric conductivity of the graphene is recovered more thoroughly; and the graphene isprepared. The method provided by the invention is a method for preparing the graphene by a low-temperature chemical method, which is suitable for large-scale industrial production. The method has theadvantages of low reduction temperature, mild and controllable reaction, more thorough reduction, environmental-friendly performance, suitability to industrial production, etc.

Description

technical field [0001] The invention belongs to the technical field of chemical synthesis of graphene, and in particular relates to a method for preparing graphene by a low-temperature chemical reduction method, specifically a method for preparing a graphite nanomaterial with a single carbon atom thickness by low-temperature catalytic reduction. The graphene prepared by this method can be widely used in the fields of microelectronic devices, sensors and new energy materials. Background technique [0002] Graphene is a flake graphite material with a thickness of one carbon atom discovered by British scientists in 2004. Due to the long-range π-conjugated bonds of graphene, it has excellent properties in electricity, mechanics, and heat. It will be a new material with a wide range of uses, and it is a current research hotspot. [0003] At present, the preparation methods of graphene mainly include mechanical exfoliation method, chemical vapor deposition method, epitaxial growt...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B31/04
Inventor 林红赵晓冲刘辰洋李俊峰李建保
Owner TSINGHUA UNIV
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