Thin-layer boron nitride nano-sheet preparation method

Abstract

The invention discloses a thin-layer boron nitride nano-sheet preparation method, which comprises: mixing a boron nitride raw material and an intercalator, putting into a sealed environment, heating,and carrying out an intercalation reaction, so that the intercalator molecules are partially or completely inserted into the layered structure of the boron nitride to form intercalated boron nitride;and vaporizing or decomposing the intercalator molecules in the intercalated boron nitride to generate gas, or carrying out a reaction on the intercalator molecules in the intercalated boron nitride and a selected chemical substance to generate gas, so the boron nitride lamellas are subjected to cleaving and stripping so as to obtain the thin-layer boron nitride nano-sheet. Compared with the method in the prior art, the preparation method of the invention has the following characteristics that the low-cost, rapid, efficient and large-scale preparation of boron nitride nano-sheets can be achieved, and the prepared boron nitride nano-sheets have advantages of large lamellar layer, less layer number and the like, and can be applied to industrial large-scale application.

Description

technical field [0001] The invention relates to a method for preparing a two-dimensional nanometer material, in particular to a method for preparing a thin-layer boron nitride nanosheet, and belongs to the technical field of nanomaterial preparation. Background technique [0002] As a research hotspot in the field of nanoscience in recent years, two-dimensional nanomaterials, especially graphene, molybdenum sulfide, boron nitride, etc., have a series of special quantum effects such as surface effects, small size effects, quantum size effects, and macroscopic tunnel effects. , so that the properties of sound, light, electricity, magnetism, heat, and mechanics have undergone major changes compared with macroscopic materials, and people have increased people's enthusiasm for research on two-dimensional nanomaterials. Graphene, which has been a hot research material in recent years, has been theoretically confirmed that the thermal conductivity of single-layer graphene is as hig...

AI Technical Summary

Problems solved by technology

This method can obtain high-quality and large-area boron nitride thin films. However, this method not only has the problems of high temperature, expensive catalysts and precursors, but also has limited output, which is not suitable for thermal conductivity additive applications.

In the top-to-bottom preparation method, due to the ionic bonds between the layers of boron nitride itself, it is much more difficult to exfoliate than graphene.

Pacile et al. tried to use mechanical exfoliation to prepare boron nitride nanosheets. Similar to the preparation of graphene, the yield of this method is too low and can only be used for basic research; people have also done a lot of work in liquid phase cleavage. : Zhi et al. see that boron nitride is added to the DMF solution and ultrasonicated for 10 hours, and a boron nitride dispersion of 0.01-0.03 mg / ml can be obtained, while other conventional solvents such as one-dichloroethane, NMP, DMAc, isopropyl Alcohol, etc., are also used to prepare thin-layer boron nitride by ultrasonic cleavage. However, this method requires long-term ultrasonication, and the energy loss is large, and the yield of boron nitride prepared is low, and the flakes are broken, which is not conducive to nitrogen Boron nitride is used as a thermally conductive filler; another conventional method for preparing thin-layer boron nitride nanosheets is the ball milling method. DongjuLee et al. used a method of NaOH-assisted ball milling for 10 hours combined with ultrasound to prepare four-layer boron nitride nanosheets with a lateral size of up to 4 layers. Thin-layer h-BN above 1.5um, this method increases the yield of boron nitride nanosheets to 18%. Lin et al. ball milled boron nitride with ODA, ammonia, etc. to obtain a thickness of 50nm and a size of For boron nitride microchips of about 5 microns, the preparation of boron nitride by ball milling is a method for macro-preparation of boron nitride, but purely mechanical ball milling greatly reduces the plane size of boron nitride, and the boron nitride prepared by this method Boron is mostly thick (dozens or even hundreds of layers), and it is difficult to obtain boron nitride nanopowder with thin layers and large areas

Other methods for preparing boron nitride nanosheets include high-pressure microfluidic method, oxidation exfoliation method, etc. Although these methods can prepare a large number of thin-layer boron nitride to a certain extent, the size of the boron nitride prepared is small. The number of layers is thick, and it is difficult to raise the thermal conductivity of the composite material to a higher level

Images