Utilize the method for preparing graphene from expanded graphite

Abstract

The invention discloses a method for preparing graphene by utilizing expanded graphite, which comprises the following steps: (1) expanded graphite and a sulfuric acid solution are added into a reactoraccording to the weight ratio of 1:(2 to 3.5), the concentration of the sulfuric acid solution is 93 to 95 percent, two polar plates are inserted in parallel into the expanded graphite dissolved in the sulfuric acid solution and expanded, and expanding treatment is carried out for 4 to 6 hours; (2) suction filtration is carried out, deionized water is then added for neutralization until pH is 6.8to 7.2, and thereby slurry is obtained; (3) the slurry is treated by microwaves; (4) 95 to 97 percent by mass of deionized water, 1.5 to 2.5 percent by mass of a dispersant and 1.5 to 2.5 percent bymass of slurry treated by microwaves in step (3) are stirred to be uniformly mixed, shear emulsification is carried out, and the treatment time is 7 to 9 hours; (5) the slurry obtained in step (4) isspray-dried, and spraying is continued for 5 to 10 seconds; (6) the material obtained in step (5) is spray-dried again, and spraying is continued for 3 to 8 seconds. The preparation method disclosed by the invention has the advantage that prepared graphene is thinner and has fewer layers.

Description

technical field [0001] The invention relates to the technical field of graphene preparation, more specifically, it relates to a method for preparing graphene by utilizing expanded graphite. Background technique [0002] Graphene refers to a planar crystalline material with a graphitic carbon six-membered ring conjugated structure. It is the only two-dimensional free atomic crystal discovered so far. Due to its special nanostructure and excellent physical and chemical properties, it has been shown in many fields such as biomedicine, catalysis, energy storage electronics, optics, magnetism, and sensors. It has great application potential and has received extensive attention and research from the scientific and industrial circles. [0003] At present, the methods for preparing graphene mainly include exfoliation graphite intercalation compound method, liquid phase exfoliation method and micromechanical exfoliation method. In the prior art, you can refer to the Chinese inventi...

AI Technical Summary

Problems solved by technology

[0004] The existing method uses chemical intercalation and exfoliation of graphite to prepare a large amount of high-quality graphene, inserts the intercalation agent into the graphite layer, and then treats it with microwaves, so that there is no rapid and violent release of gas between the layers, and the graphite is exfoliated into graphene. , the graphene prepared by this method cannot guarantee sufficient intercalation, and the prepared graphene and Purdue can only reach tens of nanometers, and the layer distribution is difficult to control

[0005] In June 2009, Nen-WenPu et al. made graphene by rapidly depressurizing supercritical carbon dioxide glass. They first placed a certain amount of powdered natural graphite in a high-pressure container with a heater and temperature control, and introduced carbon dioxide Make the pressure of the container reach 100bar, start heating and place the container at a temperature of 45°C. At this pressure and temperature, the carbon dioxide is in a supercritical state. Completely overcome the force between graphite layers and exfoliate graphene, but it needs to be carried out under high pressure conditions, and the number of layers is mostly about 10 layers, and the number of layers is relatively high

Then put the monocrystalline silicon wafer into the acetone solvent, and "fish out" the single-layer graphene to obtain graphene. The graphene is prepared by the micromechanical exfoliation method, and the yield is too low, and the number of layers is high. thicker value

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