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Method for preparing graphene quantum dot powder on large scale

A graphene quantum dot and powder technology, applied in graphene, nanotechnology, nanocarbon and other directions, can solve the problems of long preparation period, small preparation amount, high energy consumption, etc. The effect of route innovation

Active Publication Date: 2013-08-28
SHANGHAI INST OF MICROSYSTEM & INFORMATION TECH CHINESE ACAD OF SCI
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

For example: 201210134688 "Method for preparing fluorescent graphene quantum dots by solvothermal method" first prepares graphene oxide, and then uses solvothermal to "shear" graphene oxide into quantum dots; 201210106750 "A method for preparing graphene quantum dots" It is to add amine passivating agent in the hydrothermal "shearing" process, the disadvantage is high heat and high energy, and low yield; in this kind of method, there is 201110092085 "A Method for Ultrasonic Chemical Preparation of Graphene Quantum Dots", which uses ultrasonic waves to oxidize raw materials The reduction "shearing" is completed in one step, but the preparation period is long, the yield is low, and the distribution of quantum dots is not uniform; 201110202165 "Preparation method of graphene oxide quantum dots based on photocatalytic oxidation", combined with ultraviolet Radiation preparation of graphene oxide quantum dots, the distribution of quantum dots prepared by this method is improved, but it is difficult to prepare high-yield, and it is difficult to control the shape and edge morphology of quantum dots
Also Electrochemical Preparation of Luminescent Graphene Quantum Dots from Multiwalled Carbon Nanotubes by Chem.Eur.J. in 2012 and Facile synthesis of water-soluble, highly fluorescent graphene quantum dots as a robust biological label for stem cells by J.Mater.Chem. , using electrochemical exfoliation to prepare graphene quantum dots with better water solubility, but the pre-processing work of raw material graphite takes a long time, the later purification steps also take a long time, and the product yield is not high
201110109954 "Method for preparing graphene quantum dots by ultraviolet lithography dry method" uses ultraviolet light to etch graphene on mica sheets to obtain graphene quantum dots. The disadvantages of this method are radiation, large energy consumption, and small preparation volume; in addition There is also Graphene Quantum Dots at Room Temperature carved out from Few-Layer Graphene published by Nano Letter in 2012, which uses electron beam etching to prepare graphene quantum dots.
Li Changming of Nanyang Technological University in Singapore and his collaborators published a paper entitled One-step and high yield simultaneous preparation of single-and multi-layer graphene quantum dots from CX-72carbon black on J.Mater.Chem. in 2012, using 30nm Carbon black particles were used as raw material in HNO 3 Medium and long-term high-temperature reflux, and then centrifugation to obtain two sizes of graphene quantum dots, but the structure of carbon black raw materials is complex, non-sp 2 Many structures affect the quality of quantum dots
[0014] In addition, another important feature of preparing graphene quantum dots in the prior art is based on the solution method, and there is no technology for preparing graphene quantum dot powder
The concentration of graphene quantum dots in aqueous solution is limited, resulting in the low yield of the current preparation process, which restricts the application of graphene quantum dots

Method used

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  • Method for preparing graphene quantum dot powder on large scale
  • Method for preparing graphene quantum dot powder on large scale
  • Method for preparing graphene quantum dot powder on large scale

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0045] The first step: take 325 meshes of natural flake graphite and carry out wet grinding: the grinding wet material contains 35wt% graphite, 5wt% dispersant (the dispersant is a mixed dispersant, including sodium carboxymethyl cellulose and sodium polyacrylate, both The mass ratio is 1:1, add ammonia water to adjust the pH value to 12), and the rest is water; grind for 6 hours, add an appropriate amount of water every 1 hour during the grinding process to ensure that the viscosity of the wet material and the percentage of graphite remain unchanged. After grinding, Dry at 60°C for 20h; the average particle size of the prepared graphite nanoparticles is 50nm, and the TEM picture is as follows figure 1 shown;

[0046] The second step: adopt the improved Brodie method to prepare nano-graphite oxide, take 4g of nano-graphite prepared in the first step and add it to 70mL concentrated HNO 3 (67wt%), the oxidant NaClO at 0°C 3 (66g) was slowly added to concentrated HNO 3 , stirr...

Embodiment 2

[0051] The first step: take the natural flake graphite with a particle size of 200 meshes and carry out wet grinding: the grinding wet material contains 30wt% graphite, 5wt% dispersant (the dispersant is a mixed dispersant, including sodium carboxymethylcellulose and sodium polyacrylate, The mass ratio of the two is 1:1, add ammonia water to adjust the pH to 12), and the rest is moisture: water / ethanol mixture; grind for 6 hours, add appropriate amount of moisture every 30 minutes during the grinding process to ensure the viscosity of the wet material and the percentage of graphite The content remains unchanged, and vacuum drying at 80° C. for 18 hours after grinding is completed; 25 g of nano-graphite particles with a particle diameter of 100 nm are prepared.

[0052] The second step: using the improved Staudenmaier method to prepare intercalated nano-graphite oxide: take 25g of finely ground graphite nanoparticles and add them to a mixture of 285mL concentrated nitric acid (c...

Embodiment 3

[0055] The first step: prepare nano-graphite particles, same as Example 2;

[0056]The second step: prepare nano-graphite oxide by the improved Hummers method: get 70ml of 98wt% concentrated sulfuric acid, add 5g nano-graphite particles and 4g NaNO respectively during stirring 3 , control the temperature of the reaction solution at 0-5°C, slowly add 18g KMnO 4 Powder, stir and react for 1h; raise the temperature to 35°C, react for 3h; add 100ml of deionized water, raise the temperature of the reactant to 95°C, and react for 1h; dilute the reaction solution with deionized water and add 20ml of 30wt% H 2 o 2 , stirred for 1 h; filtered and washed with 1M HCl for 3-5 times, then filtered and washed with deionized water until neutral, and the obtained nano graphite oxide was dried at 60 ° C for 20 h to obtain 6.5 g of first-order intercalated nano graphite oxide;

[0057] Step 3: Take 1g of intercalated nano-graphite oxide, lay it flat in a non-closed crucible with a cover (leng...

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Abstract

The invention relates to a method for preparing graphene quantum dot powder on a large scale. Proceeding from natural flake graphite, the method for realizing the large-scale preparation of the graphene quantum dot powder comprises the following three steps of: step one. transforming the natural flake graphite into graphite nanometer particles; step two. transforming the graphite nanometer particles into first-order intercalation nanometer graphite oxide; and step three. placing the first-order intercalation nanometer graphite oxide in a non-sealed crucible with a cover, and carrying out thermal treatment in air to obtain the graphene quantum dot powder. The method can be used for realizing the 100% transformation from the intercalation nanometer graphite oxide particles to the graphene quantum dot powder by taking the low-cost natural flake graphite as a raw material in combination of a ball-milling grinding intercalation technology for volume production and a unique thermal treatment technology and breaks through the technical bottleneck that quantum dots can only be obtained in a solution.

Description

technical field [0001] The invention relates to a method for preparing graphene quantum dot powder in a large amount, and belongs to the technical field of new inorganic materials. Background technique [0002] Definition of Graphene Quantum Dots [0003] The concept of quantum dots was proposed in the 1980s. It refers to a semiconductor nanostructure. The band gap depends on the size and shape of quantum dots. It can be used to develop computers, light-emitting diodes, solar cells, lasers, and medical imaging equipment. In the 1990s, quantum dots were successfully applied to bioluminescence labeling, setting off a wave of research on quantum dots. With the gradual deepening of the research on quantum dots, it is found that the toxicity of heavy metal quantum dots, such as CdTe, PbSe, CdSe and InAs, will cause irreparable damage to human health and the environment, hindering the long-term development of heavy metal quantum dots . Therefore, scientists at home and abroad, ...

Claims

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Application Information

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IPC IPC(8): C01B31/04B82Y40/00C01B32/184
Inventor 孙静丁古巧李修兵徐旭光谢晓明江绵恒
Owner SHANGHAI INST OF MICROSYSTEM & INFORMATION TECH CHINESE ACAD OF SCI
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