Preparation method of graphene microspheres

Abstract

The invention discloses a preparation method of graphene microspheres. The preparation method comprises the following steps: 1) adjusting the pH value of an aqueous phase system of an aqueous solutionof graphene oxide to 9-11 by using an alkaline compound; 2) preparing a composite oil phase system of liquid paraffin and carbon tetrachloride, wherein the volume ratio of the liquid paraffin to thecarbon tetrachloride is (6:1)-(15:1); and 3) adding a surfactant into the composite oil phase system, adding the aqueous phase system in the step 1) according to a volume ratio of the oil phase to thewater phase of (2:1)-(8:1), then adding a diamine compound, and carrying out a stirring reaction for 3-8 hours at a temperature of 40-100 DEG C to obtain the graphene oxide microspheres. According tothe invention, a reverse emulsion system containing a composite oil phase is adopted, the graphene is assembled together through hydrogen bonds or Van der Waals' force under the action of the diaminecompound, so that the graphene has uniform and controllable size distribution, enough strength and a porous structure, a high-strength porous spherical shape is formed and maintained, and the application range of the graphene in a catalyst carrier is expanded.

Description

technical field [0001] The invention relates to a method for preparing spherical graphene, in particular to a method for preparing graphene microspheres by an inverse emulsion method. Background technique [0002] Graphene is a new material with a single-layer sheet structure composed of carbon atoms. It is a planar film composed of carbon atoms in a hexagonal honeycomb lattice with sp2 hybrid orbitals. It is only one carbon atom thick ( 0.334nm) two-dimensional material. Graphene is not only the thinnest known material, but its theoretical specific surface area is 2630m2 / g, and 1.0g of graphene can cover the entire football field. It also has very high mechanical properties, with a theoretical strength of 130GPa; When graphene is used as raw material to prepare polyolefin catalyst carrier, the carrier material has very good mechanical strength, which effectively guarantees the mechanical strength of the carrier material during the polymerization reaction, and has a large s...

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Problems solved by technology

[0003] At present, there are roughly four methods for obtaining flake graphene materials; one is to use the mechanical exfoliation method, that is, the graphite flakes are first peeled off from the graphite, and then the two sides of the graphite flakes are stuck on a special adhesive tape. At the same time, the graphite sheet is separated. This method is easy to operate, but the size of the prepared graphene is limited, and the number of layers of graphene cannot be controlled.

The second is the chemical vapor deposition (CVD) method. Large-area high-quality graphene can be prepared by the CVD method, but there are still some problems to be solved in this method.

The third is the epitaxial growth method, that is, by heating a large area of ​​single crystal SiC at high temperature to grow graphene on it, removing Si under ultra-vacuum or normal pressure to leave C, and then obtaining a graphene thin layer with an area similar to that of the original SiC , but the graphene produced by this method still cannot achieve a uniform thickness, and the different substrate materials used will have different effects on the growth of graphene, making it difficult to separate graphene from the substrate material

[0013] In short, although various methods in the prior art can obtain spherical graphene, the preparation method is mostly a physical condensation process. Because the intermolecular force formed by the surface tension of the liquid is weak, the mechanical strength of the obtained graphene sphere is generally low, which limits its use. Applications in many fields, especially in the field of catalyst supports

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