CN113104821A

CN113104821A - Preparation method of hexagonal nano boron nitride based on cholate intercalation and ball-milling exfoliation

Info

Publication number: CN113104821A
Application number: CN202010033017.2A
Authority: CN
Inventors: 冯奕钰; 周钰; 张乐康; 严前程; 马馨茹; 何思佳
Original assignee: Tianjin University
Current assignee: Tianjin University
Priority date: 2020-01-13
Filing date: 2020-01-13
Publication date: 2021-07-13

Abstract

The invention discloses a method for preparing hexagonal nano boron nitride based on cholate intercalation and ball milling stripping, which comprises the steps of preparing a boron nitride material containing cholate intercalation agent and water as a solvent, adding SiC balls or agate balls, stripping by using a ball milling method, and finally preparing the hexagonal nano boron nitride by assisting ultrasonic separation and differential centrifugation. The stripping method disclosed by the invention is low in required temperature, simple in equipment, free of high temperature, low in stripping cost and free of further operation, has great advantages in production cost and production equipment, is beneficial to quickly and efficiently preparing the two-dimensional hexagonal nano boron nitride, and is expected to realize industrial production of the two-dimensional hexagonal nano boron nitride.

Description

Preparation method of hexagonal nano boron nitride based on cholate intercalation and ball-milling exfoliation

Technical Field

The invention relates to a method for preparing hexagonal nano boron nitride based on cholate intercalation and ball milling stripping, which belongs to the field of nano material preparation, has great advantages in production cost and production equipment, and is expected to realize industrial production in the future.

Background

In recent years, the two-dimensional nano material continuously receives international research attention, and has corresponding research in the fields of energy storage devices, photoelectric conversion and the like. Two-dimensional nano materials such as graphene, boron nitride, metal sulfide and the like have unique structural properties, so that research interest of people is aroused. Due to the specific structure and anisotropy of the layered structure materials, the regulation and control of the material performance can be realized by reducing the dimensionality, intercalating and functionally modifying methods.

Due to the structure of the boron nitride material, interaction force contained between the sheet layers is weak, and the peeling is relatively easy to realize layer to layer. Scientists have made intensive studies and have made great progress in the preparation of nano boron nitride. The method is classified according to instruments used in the experiment, and mainly comprises three methods, namely an arc discharge method, a laser ablation method, a mechanical ball milling method and the like.

The arc discharge method has the advantages of harsh reaction conditions, extremely high temperature requirement, large energy loss and high danger coefficient, the two-dimensional hexagonal nano boron nitride sheet prepared by the method has relatively low production amount, and the product contains metal impurities due to the relationship of electrodes. The laser ablation method has the disadvantages of complicated equipment, high cost and low growth rate. Compared with an arc discharge method and a laser ablation method, the mechanical ball milling method does not need to be heated to a high temperature, the process flow is simple, the cost is low, and the method has obvious cost advantage and temperature advantage. The existing mechanical stripping method can rapidly strip a bulk material to generate a nano boron nitride sheet, but the stripping efficiency is low, and the quality and the shape of the formed nano material are not uniform, so that it is still a great challenge to rapidly and efficiently prepare high-quality nano boron nitride.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a method for preparing hexagonal nano boron nitride based on cholate intercalation and ball milling stripping, which can reduce the energy consumption for preparing nano boron nitride and reduce the preparation cost.

The technical purpose of the invention is realized by the following technical scheme.

A preparation method of hexagonal nano boron nitride based on cholate intercalation and ball milling stripping comprises the following steps: using water as dispersion medium, adding boron nitride, cholate and grinding balls, carrying out ball milling after uniform mixing, carrying out ultrasonic treatment after ball milling, then carrying out centrifugal treatment, finally collecting supernatant after centrifugation, and drying to obtain white boron nitride powder (hexagonal nanometer boron nitride), wherein: the cholate is sodium cholate, sodium deoxycholate or sodium taurocholate, and when ball milling is carried out, the ball milling rotating speed is 150-250 r/min, and the ball milling time is 10-15 hours; when carrying out ultrasonic treatment, the ultrasonic power is 100-500 w, and the ultrasonic time is 10-20 min; when the centrifugal process is carried out, the centrifugal rotating speed is 1800-2200 r/min, and the centrifugal time is 10-20 min.

And the mass ratio of the boron nitride to the cholate is (8-10): 1, the mass of boron nitride and the grinding ball is 1: (1-1.5).

And the grinding balls are SiC balls or agate balls.

And when the ball milling is carried out, the ball milling rotating speed is 200-250 r/min, and the ball milling time is 10-12 hours.

Furthermore, when the ultrasonic treatment is carried out, the ultrasonic power is 300-500 w, and the ultrasonic time is 15-20 min.

Furthermore, the centrifugation is carried out at a centrifugation speed of 2000-2200 r/min for 10-15 min.

Moreover, the preparation is carried out at room temperature of 20-30 ℃ and normal pressure (i.e. one atmosphere).

The invention discloses a method for preparing hexagonal nano boron nitride based on cholate intercalation and ball milling stripping, which comprises the steps of preparing a boron nitride material containing cholate intercalation and water as solvents as shown in figure 1, adding SiC balls or agate balls, stripping by a ball milling method, and finally preparing the hexagonal nano boron nitride by assisting ultrasonic separation and differential centrifugation. The stripping method disclosed by the invention is low in required temperature, simple in equipment, free of high temperature, low in stripping cost and free of further operation, has great advantages in production cost and production equipment, is beneficial to quickly and efficiently preparing the two-dimensional hexagonal nano boron nitride, and is expected to realize industrial production of the two-dimensional hexagonal nano boron nitride.

Drawings

FIG. 1 is a schematic flow chart of the cholate intercalation process for preparing a nano boron nitride material.

FIG. 2 is a graph of an infrared spectrum of a boron nitride raw material before being stripped according to the technical scheme of the invention.

FIG. 3 is a graph of an infrared spectrum of nano boron nitride stripped by the technical scheme of the invention.

FIG. 4 is a transmission electron microscope photograph of nano boron nitride after being stripped by the technical scheme of the invention.

FIG. 5 is a photograph showing the electron diffraction pattern of nano boron nitride after being peeled off by the present invention.

Detailed description of the preferred embodiment

The following is a further description of the invention and is not intended to limit the scope of the invention.

Example 1

(1) Proportioning, adding 2g of boron nitride and 2g of SiC microspheres (serving as grinding balls) in a ball mill, adding 0.2g of sodium cholate serving as an intercalation agent, and using water as a solvent.

(2) Ball milling, namely putting the prepared materials into a ball mill, regulating the rotating speed to 150r/min, and carrying out ball milling for 15 h.

(3) And (4) performing ultrasonic treatment, and performing ultrasonic treatment for 10min at 500w after the ball milling is finished.

(4) Centrifuging, namely putting the ultrasonically treated materials into a centrifuge at the rotating speed of 2200r/min, and centrifuging for 10 min.

(5) Collecting, taking supernatant of the centrifuged material, and drying to obtain a final product.

Example 2

(1) Proportioning, adding 2g of boron nitride and 2g of SiC microspheres in a ball mill, adding 0.2g of sodium deoxycholate as an intercalating agent, and using water as a solvent.

(2) And (3) ball milling, namely putting the prepared materials into a ball mill, regulating the rotating speed to 250r/min, and carrying out ball milling for 10 hours.

(3) And (4) performing ultrasonic treatment, and performing ultrasonic treatment for 20min at 100w after the ball milling is finished.

(4) Centrifuging, namely putting the materials subjected to ultrasonic treatment into a centrifuge at the rotating speed of 1800r/min for 20 min.

Example 3

(1) Proportioning, adding 2g of boron nitride and 3g of SiC microspheres in a ball mill, adding 0.2g of sodium taurocholate serving as an intercalation agent, and using water as a solvent.

(2) Ball milling, namely putting the prepared materials into a ball mill, regulating the rotating speed to 200r/min, and carrying out ball milling for 12 h.

(3) And (4) performing ultrasonic treatment, and performing ultrasonic treatment for 15min at 300w after the ball milling is finished.

(4) And (4) centrifuging, namely putting the ultrasonically processed materials into a centrifuge, wherein the rotating speed is 2000r/min, and centrifuging for 15 min.

In the characterization of examples 1 to 3, a small amount of centrifuged boron nitride supernatant was collected from a petri dish and dried in an oven for 24 hours to obtain a white boron nitride powder. A sample of infrared spectra was prepared by the halide tablet process by mixing potassium bromide and boron nitride in a mass ratio of about 200:1, carefully grinding and pressing into a transparent sheet. As shown in FIGS. 2 and 3, both before and after boron nitride stripping exhibited two distinct peaks, 1400cm^-1The left and right peaks correspond to stretching vibration of hexagonal boron nitride B-N bond, 800cm^-1The left and right peaks correspond to bending vibration of a B-N bond of the hexagonal nitriding shed, the positions and the intensities of the front peak and the rear peak are almost unchanged before stripping, and other obvious mixed peaks do not exist basically, so that the pure nano hexagonal nitriding shed can be obtained by judging stripping.

As can be seen from the attached figure 4, the stripped boron nitride has a nanosheet structure, is light in color, and has a transverse size of 100-200 nm, which shows that under the action of a cholate intercalator and ultrasound, the boron nitride layers are separated from one another, the number of the boron nitride layers is obviously reduced, and the thickness of the boron nitride layers is obviously reduced. Meanwhile, the color depth of the nano-sheets is basically consistent, the texture is relatively uniform, and no other substances exist, which indicates that the nano hexagonal nitriding greenhouse prepared by the method has fewer impurities. As can be seen from fig. 5, the electron diffraction spots form a regular two-dimensional grid shape, have uniform intensity, and exhibit symmetrical distribution, so that we can determine that the nano boron nitride stripped by the cholate intercalation method is a relatively pure single crystal and has good crystallinity.

The preparation of the nano boron nitride material can be realized by adjusting the process parameters according to the content of the invention, and the performance basically consistent with the invention is shown. The invention has been described in an illustrative manner, and it is to be understood that any simple variations, modifications or other equivalent changes which can be made by one skilled in the art without departing from the spirit of the invention fall within the scope of the invention.

Claims

1. A preparation method of hexagonal nano boron nitride based on cholate intercalation and ball milling stripping is characterized by comprising the following steps: using water as dispersion medium, adding boron nitride, cholate and grinding balls, carrying out ball milling after uniform mixing, carrying out ultrasonic treatment after ball milling, then carrying out centrifugal treatment, finally collecting supernatant after centrifugation, and drying to obtain white boron nitride powder (hexagonal nanometer boron nitride), wherein: the cholate is sodium cholate, sodium deoxycholate or sodium taurocholate, and when ball milling is carried out, the ball milling rotating speed is 150-250 r/min, and the ball milling time is 10-15 hours; when carrying out ultrasonic treatment, the ultrasonic power is 100-500 w, and the ultrasonic time is 10-20 min; when the centrifugal process is carried out, the centrifugal rotating speed is 1800-2200 r/min, and the centrifugal time is 10-20 min.

2. The method for preparing hexagonal nano boron nitride based on cholate intercalation and ball milling exfoliation as claimed in claim 1, wherein the mass ratio of boron nitride to cholate is (8-10): 1, the mass of boron nitride and the grinding ball is 1: (1-1.5).

3. The method for preparing hexagonal nano boron nitride based on cholate intercalation and ball milling exfoliation according to claim 1 or 2, characterized in that the grinding balls are SiC balls or agate balls.

4. The method for preparing hexagonal nano boron nitride based on cholate intercalation and ball milling exfoliation as claimed in claim 1 or 2, wherein the ball milling rotation speed is 200-250 r/min, and the ball milling time is 10-12 hours.

5. The method for preparing hexagonal nano boron nitride based on cholate intercalation and ball milling exfoliation as claimed in claim 1 or 2, wherein the ultrasonic power is 300-500 w and the ultrasonic time is 15-20 min.

6. The method for preparing hexagonal nano boron nitride based on cholate intercalation and ball milling exfoliation as claimed in claim 1 or 2, wherein the centrifugation is carried out at a rotation speed of 2000-2200 r/min for 10-15 min.

7. The method for preparing hexagonal nano boron nitride based on cholate intercalation and ball milling exfoliation as claimed in claim 1 or 2, wherein the preparation is performed at room temperature of 20-30 ℃ and normal pressure (i.e. one atmosphere).