Preparation method of large-size graphene oxide or graphene

A graphene, large-scale technology, which is applied in the field of large-scale graphene oxide or graphene preparation, can solve the difficulty of solid-liquid separation of graphene oxide suspension, cannot be solved, and the radial size of graphene sheets is small, reducing Graphene size and other issues, to achieve the effect of facilitating large-scale industrial production, low production cost, and avoiding uneven expansion

Active Publication Date: 2016-02-03
FUDAN UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Although this method has high oxidation efficiency and stripping efficiency, it involves ultrasonic assistance, which inevitably reduces the size of graphene to a certain extent, and the difficulty of solid-liquid separation of graphene oxide suspensions still cannot be solved.
The patent "A method for preparing graphene fibers by self-assembly of large sheets of graphene oxide" (CN10374126A) first uses strong acid to intercalate graphite, expands at high temperature, and then uses Hummers method for oxidation, centrifugation, and dialysis to obtain graphene sheets The radial size is small (20-80 μm), the preparation process is complicated, and the cost is high
In 2014, Nature Communications reported a 1-hour method for preparing single-layer graphene oxide (DOI: 10.1038 / ncomms6716). However, although this method is green and environmentally friendly, it is only suitable for small-sized graphite raw materials
At present, how to prepare large-size graphene oxide and high-conductivity graphene with high efficiency and high yield has not been published or reported.

Method used

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  • Preparation method of large-size graphene oxide or graphene

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] 50 mL of concentrated sulfuric acid and 5 g of ammonium persulfate were mixed and stirred at 5 °C for 10 min, and 1 g of flake graphite was added, and stirred continuously in a water bath at 20 °C for 10 h to obtain intercalated graphite (GICs). Then slowly put into 200mL 0.1mol / L oxalic acid solution, react rapidly at room temperature for 2 days, filter and wash with water to obtain graphene aggregates. Next, slowly pour into a mixture of 40 mL of concentrated sulfuric acid and 2 g of potassium permanganate, let stand at 35° C. for 6 h, and then filter and wash with water. Add 1L of deionized water, and vibrate for 10 min under an oscillating bed at 500 rpm to obtain a uniform graphene dispersion. Microscopic results show that the average radial size of the obtained graphene oxide can reach more than 100 microns, and more than 90% are single layers. figure 1 is the SEM image of the obtained graphene oxide flakes, with radial dimensions up to 450 μm. figure 2 The appea...

Embodiment 2

[0034] After the graphene oxide suspension obtained in Example 1 was filtered to form a film, it was heat-treated at 800°C for 60 minutes, and pressed for 5 minutes at a pressure of 20MPa. The four-probe measurement results showed that the conductivity of the film could reach 600S / cm above.

Embodiment 3

[0036] Mix 30 mL of concentrated sulfuric acid and 10 mL of concentrated nitric acid in an ice-water bath at 5°C and stir for 10 min, add 1 g of graphite flakes, stir continuously in a water bath at 20°C for 6 h, and then filter to obtain GICs. Then, slowly put into 200mL0.1mol / L oxalic acid solution, react at room temperature for 1d, filter and wash with water to obtain graphene aggregates. Next, slowly pour into a mixture of 40 mL of concentrated sulfuric acid and 2 g of potassium permanganate, let stand at 35° C. for 6 h, and then filter and wash with water. Add 1L of deionized water, and vibrate under an oscillating bed at 500rpm for 10min. The obtained graphene oxide has an average radial size of more than 100 microns, and more than 90% of it is a single layer. It is reduced by hydriodic acid solution (57%) at 60°C for 2h After that, the conductivity reaches above 600S / cm.

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Abstract

The invention discloses a preparation method of large-size graphene oxide or graphene. The preparation method mainly utilizes graphite as a raw material and comprises that 1, under the action of an intercalator and an expanding agent, graphite fully releases interlayer spaces so that interlayer interaction is reduced and a graphene aggregate is obtained, 2, the graphene aggregate is oxidized by an oxidizing agent, and then the oxidized graphene aggregate is peeled in water under gentle mechanical action so that a large area of a dispersion liquid of graphene oxide is obtained, and 3, the peeled graphene oxide is reduced by a reducer or heat treatment so that high conductivity graphene is obtained. The preparation method utilizes cheap raw materials, has a simple process, can be controlled easily, realizes fast and high efficiency solid-liquid separation, is convenient for industrial large scale production, prevents graphene crystal structure destroy caused by high energy supersonic wave, high speed shearing or fluid crushing. The obtained graphene has a large size and high conductivity and can be popularized and used in fields of high efficiency heat management, flexible display, energy conversion and storage.

Description

technical field [0001] The invention belongs to the technical field of graphene oxide and graphene preparation, and relates to a method for preparing large-scale graphene oxide or graphene on a large scale. Specifically, graphite is used as a raw material, and graphene oxide is obtained through intercalation, expansion, and oxidation processes. The aggregates are exfoliated under gentle mechanical force to obtain large-size graphene oxide, and large-size graphene is obtained after reduction. Background technique [0002] Transparent conductive films have high light transmittance and excellent conductivity, and have broad application prospects in the fields of liquid crystal displays, solar cells, light-emitting diodes, and smart windows. The disadvantages of indium tin oxide (ITO), such as high price and brittleness, greatly restrict its application on transparent conductive films. Graphene is carbon atoms with sp 2 The thinnest two-dimensional material that is hybridized ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B31/04
CPCC01B32/19C01B32/198C01B2204/04B82Y40/00C01B2204/22C01B2204/02B82Y30/00C01B2204/32C01B32/192
Inventor 卢红斌董雷林姗马晨
Owner FUDAN UNIV
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