A method for large-scale continuous and high-efficiency exfoliation of graphite oxide

A graphite, high-efficiency technology, applied in the field of large-scale continuous and efficient exfoliation of graphite oxide, can solve the problems of low concentration, low production efficiency, poor dispersion stability, etc., and achieve continuous and rapid production process, high production efficiency and controllable size.

Active Publication Date: 2019-05-28
NANJING TECH UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the graphene oxide prepared by mechanical exfoliation is mostly 2-10 layers or thin-layer graphite oxide microflakes, and the microscopic uniform dispersion of the exfoliated solid product in the solution cannot be achieved, and the resulting dispersion has poor stability.
[0006] At present, the exfoliation method of graphite oxide generally has problems such as low single-layer rate, low concentration, uncontrollable size, low production efficiency and high energy consumption. It is difficult to achieve large-scale continuous production of high-quality graphene oxide, which in turn affects high-quality graphene. Production is one of the key bottlenecks hindering the industrialization of graphene

Method used

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  • A method for large-scale continuous and high-efficiency exfoliation of graphite oxide
  • A method for large-scale continuous and high-efficiency exfoliation of graphite oxide
  • A method for large-scale continuous and high-efficiency exfoliation of graphite oxide

Examples

Experimental program
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Effect test

Embodiment 1

[0043] Use the optimized Hummers method to add 50 mesh natural flake graphite to 98wt% concentrated sulfuric acid. After fully stirring, add potassium permanganate in an ice-water bath. After reacting for 20-30min, the temperature is raised to 50°C to fully react to obtain graphite oxide. After diluting with water, an appropriate amount of hydrogen peroxide is added, and then the graphite oxide is washed with deionized water in a purification device until the pH of the filtrate is 6.0-7.0. The interlayer spacing of the obtained graphite oxide is 0.7-0.9nm, and diffraction peaks appear at 2θ of 9-12°.

[0044] Transfer the graphite oxide slurry discharged from the purification equipment to the pipeline circulation high-speed shearing equipment, and add deionized water to dilute its concentration to 0.5g / L, use a round hole stator head, close the outlet valve, and set the temperature at 1000 rpm Shearing and peeling at a rotating speed of 20 min to obtain a partially peeled grap...

Embodiment 2

[0050] Using the Hummers method, add 800 mesh natural flake graphite and NaNO to 98wt% concentrated sulfuric acid under ice-water bath 3 and potassium permanganate, stirred for 2 hours, then heated to 60°C, fully reacted to obtain graphite oxide, diluted with deionized water, added an appropriate amount of hydrogen peroxide, and then washed the graphite oxide with deionized water in the purification equipment until the pH of the filtrate was 6.0 -7.0. The interlayer spacing of the obtained graphite oxide is 0.7-0.9nm, and diffraction peaks appear at 2θ of 9-12°.

[0051] Add deionized water to the graphite oxide discharged from the purification equipment, dilute its concentration to 4g / L, enter the reactor-type high-speed shearing equipment, use the claw-type stator head, and shear and peel at a speed of 12000 rpm for 8 minutes to obtain Partially exfoliated graphene oxide dispersion.

[0052] After high-speed shearing, the partially exfoliated graphene oxide dispersion was ...

Embodiment 3

[0057] Add 10000 mesh natural flake graphite to 98wt% concentrated sulfuric acid and 65wt% nitric acid mixture by Staudenmaier method, add potassium nitrate after fully stirring in ice water bath, react for 24h to obtain graphite oxide, dilute with deionized water and oxidize in purification equipment The graphite was washed with deionized water until the pH of the filtrate was 6.0-7.0. The interlayer spacing of the obtained graphite oxide is 0.7-0.9nm, and diffraction peaks appear at 2θ of 9-12°.

[0058] Add deionized water to the graphite oxide discharged from the purification equipment, dilute its concentration to 10g / L, enter the probe-type high-speed shearing equipment, use a long-hole stator head, and shear and peel at a speed of 30,000 rpm for 20 seconds to obtain a part Exfoliated graphene oxide dispersion.

[0059] The partially exfoliated graphene oxide dispersion after high-speed shearing directly enters the continuous tube ultrasonic equipment under the action of...

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Abstract

The invention provides a method for large-scale, continuous and efficient graphite oxide stripping. The method comprises the following steps that purified and diluted graphite oxide dispersion liquid is delivered to a high-speed shear device, a high-speed water flow produced in the process of a high-speed mechanical shear method bumps and impacts graphite oxide to perform rapid macroscopic dispersion and partial stripping of graphite oxide; the graphite oxide dispersion liquid is introduced to a continuous ultrasonic device, the partially stripped graphite oxide having good macroscopic dispersion is rapidly stripped to obtain a single layer by virtue of a high-pressure and high-speed microjet produced by the ultrasonic cavitation effect in the process of an ultrasonic stripping method, and the microcosmic, uniformly dispersed and stable graphite oxide dispersion liquid is obtained. The method strengthens dispersion and stripping of the graphite oxide through a coupling shear field and an ultrasonic field, the obtained graphene oxide is high in single-layer rate, high in concentration and controllable in size, has the advantages of being continuous and rapid in production process, high in production efficiency, low in cost and the like and is suitable for large-scale production of graphite oxide and graphene.

Description

technical field [0001] The invention belongs to the technical field of novel nanometer materials, and in particular relates to a method for large-scale continuous and high-efficiency exfoliation of graphite oxide. Background technique [0002] Graphene has attracted widespread attention for its excellent properties in optics, electricity, mechanics, and heat, and its industrialization and large-scale application have become current hot spots. The preparation methods of graphene mainly include mechanical exfoliation method, chemical vapor deposition method, epitaxial growth method, redox method, etc. Among them, mechanical exfoliation method, chemical vapor deposition method and epitaxial growth method can prepare graphene with fewer defects, but Its production capacity is difficult to expand, and it is not suitable for large-scale production of graphene. The chemical redox method is currently one of the most promising methods for large-scale preparation of graphene at low c...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B32/198
CPCC01B2204/02C01B2204/32C01P2004/04
Inventor 暴宁钟李畅沈丽明史叶勋何大方
Owner NANJING TECH UNIV
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