Porous graphene and graphene quantum dot and preparation method of porous graphene and graphene quantum dot

A technology of graphene quantum dots and porous graphene, which is applied in the field of graphene, can solve the problems of affecting the quality of graphene quantum dots, destroying the structural integrity of graphene, and having many defects in graphene quantum dots, so as to achieve good crystal form and high defect less, high luminous efficiency

Active Publication Date: 2015-04-29
SHANXI INST OF COAL CHEM CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Top-down methods include strong acid oxidation method, hydrothermal method, microwave method, electrochemical method, etc., most of which use graphene oxide or graphene prepared by Hummers method as raw materials, and use a lot of strong Oxidants and toxic and harmful substances, and the obtained graphene quantum dots have many defects, destroying the structural integrity of graphene and affecting electron transfer, which affects the quality of graphene quantum dots from the raw material
Electrochemical method is also a kind of top-down method, and the raw material usually used is graphite rod, such as Jiong Lu et al. (ACS Nano, 2009, 8, 2367-2375) use high-purity graphite rod as electrode, and apply 3-15V voltage Graphene and graphene nanobelts are obtained by exfoliating with a DC power supply, but so far, the research on preparing porous graphene and graphene quantum dots using high-crystallinity graphene as a raw material has not been reported.

Method used

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  • Porous graphene and graphene quantum dot and preparation method of porous graphene and graphene quantum dot

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Embodiment 1

[0070] (1) Preparation of raw material graphene microsheets

[0071] With flexible graphite paper (the specific surface area of ​​the electrode is 2 square meters per gram (2m 2 / g), resistivity 1 ohm meter) is the electrode material, the distance between the two electrodes is about 20mm, separate the two electrodes with a porous membrane (polypropylene, aperture 1μm), and the ratio of the electrolyte to the graphite is 20ml / g. The DC power supply voltage is -5V—+5V alternately, the electrolyte is composed of cheap sodium perchlorate and dimethyl carbonate aqueous solution, the concentration of sodium perchlorate is 110g / L, and the concentration of water is 2g / L. Programmed charging for 48 hours, changing the charging direction every 30 minutes, the ratio of initial output current density to graphite is 0.01 ampere per gram, and the temperature is 20°C. The flexible graphite paper gradually swells. After the flexible graphite paper is completely swollen, filter out the ele...

Embodiment 2

[0077] (1) Preparation of graphene microsheets

[0078] The specific surface area of ​​the flexible graphite paper electrode is 2 square meters per gram (2m2 / g), the resistivity is 1 ohm m) as the electrode material, and the electrodes are separated by an insulating porous polypropylene film (the average pore size is 0.4 microns). The distance is 10mm and the ratio of electrolyte to graphite is 40ml / g. 16 electrodes form an electrode array and are placed in an electrolytic cell. DC power supply voltage charging -9V—+9V alternately, the electrolyte is composed of cheap sodium perchlorate and dimethyl carbonate aqueous solution, the concentration of sodium perchlorate is 140g / L, and the concentration of water is 5g / L. Programmed charging for 60 hours, changing the charging direction every 1 hour, the ratio of output current density to graphite fluctuates around 0.002 amperes per gram, and the temperature is 40°C. After the flexible graphite paper is completely swollen, press f...

Embodiment 3

[0084] (1) Preparation of graphene microsheets

[0085] The porous electrode material is made of expanded graphite and aluminum foil, with a specific surface area of ​​3.5 square meters per gram and a resistivity of 10 ohm·m. Separate the graphite electrodes (average pore size is 0.5 micron) with an insulating porous polypropylene bag, and the ratio of the electrolyte to the graphite is 50ml / g. 32 electrodes form an electrode array, and the distance between the electrodes is 5-10mm. They are connected in parallel to form 2 electrolytic cells, each with 16 electrode square arrays. The electrolyte is composed of cheap sodium perchlorate, water and dimethyl carbonate solution, the concentration of sodium perchlorate is 150g / L, the concentration of aqueous solution is 50g / L, and the mass percentage of water is 8%. DC power supply voltage charging -10V and +10V is carried out alternately, programmed charging is 48 hours, and the charging direction is changed every 8 hours. The rat...

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Abstract

The invention discloses porous graphene and a graphene quantum dot. The porous graphene comprises, but is not limited to 2-9 atomic layers, wherein each atomic layer simultaneously comprises crystal lattices and holes of graphene, but is not limited to the holes of which the apertures are 2-10nm; the area of the holes accounts for about 5%-40% of total area of each atomic layer. The graphene quantum dot is characterized by comprising 1-5 atomic layers; the boundary is in a sawtooth shape; and the dimension of the quantum dot is 2-10nm. The porous graphene disclosed by the invention is uniform in aperture distribution, and not equal in interlayer spacing; and the graphene quantum dot has the advantages of high luminous efficacy, good crystal form and few defects.

Description

technical field [0001] The invention belongs to the field of graphene, in particular to porous graphene, graphene quantum dots and a preparation method thereof. Background technique [0002] Graphene refers to a single layer of carbon atoms tightly packed into a two-dimensional honeycomb structure, which is the basic unit for constructing other dimensional carbon materials (such as zero-dimensional fullerenes, one-dimensional carbon nanotubes, and three-dimensional graphite). Single-layer graphene has a large specific surface area, excellent electrical and thermal conductivity and low thermal expansion coefficient. In particular, its high conductivity, large specific surface properties and its monolayer two-dimensional nanoscale structural properties can be used as electrode materials in bipolar plates of fuel cells, supercapacitors and lithium-ion batteries. [0003] Porous graphene not only has similar properties to graphene, but also has a larger specific surface area, u...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B31/04
Inventor 王俊中郭全贵闫蕊王俊英黄建林
Owner SHANXI INST OF COAL CHEM CHINESE ACAD OF SCI
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