阅读说明：本技术 一种利用deet剥离制备二维材料纳米片的方法 (Method for preparing two-dimensional material nanosheet by DEET stripping ) 是由 桑欣欣 聂向导 宋俊玲 刘敬成 刘仁 于 2021-09-26 设计创作，主要内容包括：本发明属于二维材料剥离技术领域,具体涉及一种利用DEET剥离制备二维材料纳米片的方法,步骤为：通过将二维材料分散于DEET或其混合溶剂中,进行超声处理将超声后的分散液通过低速离心除去未剥离的二维材料,取上清液进行高速离心后,经洗涤、干燥得到二维材料纳米片。本发明采用DEET或其与乙醇、异丙醇的混合溶剂,超声辅助二维材料剥离成二维材料纳米片,与传统有机溶剂的液相剥离相比,该溶剂体系与二维材料有更好的相互作用,所得纳米片具有更大的厚径比。此外,本发明的溶剂绿色环保,工艺简单,成本低廉,不需要复杂昂贵的设备,有利于大规模生产制备二维材料纳米片。(The invention belongs to the technical field of two-dimensional material stripping, and particularly relates to a method for preparing a two-dimensional material nanosheet by DEET stripping, which comprises the following steps: dispersing a two-dimensional material in DEET or a mixed solvent thereof, carrying out ultrasonic treatment, centrifuging the ultrasonically treated dispersion liquid at a low speed to remove the non-stripped two-dimensional material, taking the supernatant, centrifuging at a high speed, washing and drying to obtain the two-dimensional material nanosheet. According to the invention, DEET or a mixed solvent of DEET and ethanol and isopropanol is adopted, and the two-dimensional material is stripped into the two-dimensional material nanosheet under the assistance of ultrasonic waves. In addition, the solvent disclosed by the invention is green and environment-friendly, simple in process, low in cost and free of complex and expensive equipment, and is beneficial to large-scale production and preparation of the two-dimensional material nanosheet.)

1. A method for preparing a two-dimensional material nanosheet by DEET stripping is characterized by comprising the following steps:

adding the two-dimensional material into DEET or a mixed solvent thereof, carrying out ultrasonic treatment, removing the non-stripped two-dimensional material from the obtained dispersion liquid through low-speed centrifugation, taking the supernatant, carrying out high-speed centrifugation, washing and drying to obtain the two-dimensional material nanosheet.

2. The method for preparing a two-dimensional material nanosheet by means of DEET exfoliation according to claim 1, wherein the two-dimensional material is one of hexagonal boron nitride, natural flake graphite and molybdenum disulfide.

3. The method for preparing two-dimensional material nanosheets by DEET exfoliation according to claim 1, wherein the concentration of two-dimensional material in the dispersion is 1-10 mg/mL.

4. The method for preparing two-dimensional material nanosheets by DEET exfoliation according to claim 1, wherein the mixed solvent is a mixed solvent of DEET and ethanol or DEET and isopropanol.

5. The method for preparing two-dimensional material nanosheets by DEET exfoliation according to claim 4, wherein DEET and ethanol are mixed in a volume ratio of (0.1-5) to 1 in the mixed solvent.

6. The method for preparing two-dimensional material nanosheets by DEET exfoliation according to claim 4, wherein the volume ratio of DEET to isopropanol in the mixed solvent is (0.1-5) to 1.

7. The method for preparing two-dimensional material nanosheets by DEET exfoliation as recited in claim 1, wherein the ultrasonication conditions are: performing ultrasonic treatment at the power of 100-600W for 2-48 h; the parameters of the low-speed centrifugation are set as follows: centrifuging at 1000-; the parameters of the high-speed centrifugation are set as follows: centrifuging at 9000-12000rpm for 10-30 min.

8. Two-dimensional material nanosheets prepared according to the method of any one of claims 1 to 7, wherein the two-dimensional material nanosheets comprise boron nitride nanosheets, graphene nanosheets or MoS₂One of the nanosheets.

9. Two-dimensional material nanoplatelets according to claim 8 wherein the boron nitride nanoplatelets have a lateral dimension of 1-3 μm and a thickness of 1-4 nm; the above-mentionedThe transverse size of the graphene nanosheet is 2-3 mu m, and the thickness of the graphene nanosheet is 1-4 nm; the MoS₂The lateral dimension of the nano-sheet is 200-500nm, and the thickness is 1-3 nm.

10. Use of two-dimensional material nanoplatelets according to claim 9 comprising boron nitride nanoplatelets, graphene nanoplatelets or MoS₂The application of the nano sheet; the boron nitride nanosheet is used as an inorganic filler to prepare a heat conduction electric insulation polymer, and is applied to the technical fields of aerospace, 5G base stations and small electronic equipment; the graphene nanosheet is used as an inorganic filler to prepare a heat-conducting polymer or be used as a conductive material, and is applied to the technical fields of aerospace, 5G base stations and small electronic equipment; the MoS₂The nanosheet as a semiconductor material has a direct band gap, and is applied to the technical fields of photoelectric devices, thermoelectric devices and the like.

Technical Field

The invention belongs to the technical field of two-dimensional material preparation, and particularly relates to a method for preparing a two-dimensional material nanosheet by DEET stripping.

Background

Since the preparation of single-layer graphene by using an adhesive tape in 2004 and a micromechanical peeling method, the thickness of a single atomic layer, high carrier mobility and high strength of the graphene arouse extensive attention of researchers to two-dimensional materials. Two-dimensional materials exhibit many unique properties due to their unique electronic structure. Due to the special properties of the crystal structure, different two-dimensional materials have different anisotropies of electrical properties or optical properties, especially anisotropies of properties such as light absorption spectrum, Raman spectrum, second harmonic spectrum, electrical conductivity, thermal conductivity and the like, and can be applied to the fields of transparent conductive electrodes, photodetectors, diodes, transistors, heat conduction materials, solar cells, LEDs, electrocatalysts, photocatalysts and the like.

Methods for preparing ultrathin two-dimensional material nanosheets mainly include mechanical stripping methods (Abdelkader A M, Kinloch I A. mechanical stripping of 2D Crystals in Deep European solutions [ J ]. Acs Sustainable Chemistry & Engineering, 2016: acquusing chemistry.6b01195.), liquid phase stripping methods ((1) Navik R, Gai Y, Wang W, et al. Cu. associated with organic stripping of copper to copper in ethanol [ J ]. Ultrasonics Chemistry, 2018: S0417710058355. (2) Liu Y, Li R. study on inorganic stripping-treated copper-doped-deposition of copper nanoparticles [ J ]. alumina Chemistry, 2018: S1357718355 ], Cu. I. suspended copper-doped-copper-deposition of copper oxide [ J. (Chemical) deposition methods [ 9. slurry J.: slurry, J.: vapor deposition of copper oxide, No. 3. 9. slurry, J.: 9. deposition of copper oxide and copper oxide.

However, the conventional mechanical peeling method has a low yield; liquid phase stripping requires a large amount of solvent for long-time treatment, the yield is low, and the toxicity of common organic solvents is high; the chemical vapor deposition method has complex equipment and high manufacturing cost, and is difficult to realize large-scale preparation.

Based on the above, the invention provides a method for preparing a two-dimensional material nanosheet by stripping N, N-diethyl-3-methylbenzamide (DEET), so as to solve the problems of low efficiency, high toxicity and the like of using an organic solvent in a liquid phase stripping process.

Disclosure of Invention

The first purpose of the invention is to provide a method for preparing a two-dimensional material nanosheet by DEET stripping, wherein ultrasonic stripping of the two-dimensional material is assisted by DEET or a compound solvent of DEET, ethanol and isopropanol, and a solvent system of the invention has both an amide group and a benzene ring, has better interaction force with the two-dimensional material, can better strip the two-dimensional material, and simultaneously has low toxicity and is more environment-friendly.

The second purpose of the invention is to provide a two-dimensional material nano-sheet prepared by the method, wherein the two-dimensional material nano-sheet comprises boron nitride nano-sheet, graphene nano-sheet and MoS₂Nanosheets.

The third purpose of the invention is to provide an application of the two-dimensional material nanosheet.

In order to achieve the purpose, the technical scheme of the invention is as follows:

the invention provides a method for preparing two-dimensional material nanosheets by DEET stripping, which comprises the following steps:

adding the two-dimensional material into DEET or a mixed solvent thereof, carrying out ultrasonic treatment, centrifuging the ultrasonically treated dispersion liquid at a low speed to remove the non-stripped two-dimensional material, taking the supernatant liquid, carrying out high-speed centrifugation, and drying to obtain the two-dimensional material nanosheet.

Further, the two-dimensional material is hexagonal boron nitride (h-BN), natural crystalline flake graphite and molybdenum disulfide (MoS)₂) Tungsten disulfide (WS)₂) And black phosphorus.

Further, the concentration of the two-dimensional material in the dispersion is 1-10 mg/ml.

Further, the mixed solvent is a mixed solvent of DEET and ethanol or isopropanol.

Furthermore, in the mixed solvent, DEET and ethanol are mixed according to the volume ratio of 0.1-5: 1.

Furthermore, in the mixed solvent, the volume ratio of DEET to isopropanol is 0.1-5: 1.

Further, the ultrasonic treatment conditions are as follows: performing ultrasonic treatment at the power of 100-600W for 2-48 h;

the parameters of the low-speed centrifugation are set as follows: centrifuging at 1000-;

the parameters of the high-speed centrifugation are set as follows: centrifuging at 9000-12000rpm for 10-30 min.

The second aspect of the invention provides a two-dimensional material nano-sheet prepared by the method, wherein the two-dimensional material nano-sheet comprises boron nitride nano-sheet, graphene nano-sheet and MoS₂Nanosheets.

Wherein the transverse dimension of the boron nitride nanosheet is 1-3 μm, and the thickness is 1-4 nm.

The graphene nanosheet is 2-3 microns in transverse dimension and 1-4nm in thickness.

The MoS₂The lateral dimension of the nano-sheet is 200-500nm, and the thickness is 1-3 nm.

The third aspect of the present invention provides the above-mentioned boron nitride nanosheets, graphene nanosheets, MoS₂Application of the nano-sheet.

The boron nitride nanosheet is used as an inorganic filler to prepare the heat conducting and electric insulating polymer, and can be applied to the technical fields of aerospace, 5G base stations, small electronic equipment and the like.

The graphene sheet is used as an inorganic filler to prepare a heat-conducting polymer or be used as a conductive material, and can be applied to the technical fields of aerospace, 5G base stations, small electronic equipment and the like.

MoS₂The nano-sheet as a semiconductor material has a direct band gap, and the characteristic enables the material to convert electrons into photons, so that the nano-sheet can be applied to the technical fields of photoelectric devices, thermoelectric devices and the like.

Compared with the prior art, the invention has the advantages and beneficial effects that:

compared with the traditional liquid phase stripping method, the method for stripping the two-dimensional material by using the DEET has the advantages that the mixed solvent has better interaction with the two-dimensional material, and the two-dimensional material can be stripped better. The two-dimensional material nanosheet obtained by the preparation method disclosed by the invention is large in size and thin in thickness, and is a high-quality nanosheet. In addition, the solvent disclosed by the invention is green and environment-friendly, simple in process, low in cost and free of complex and expensive equipment, and is beneficial to large-scale production and preparation of the two-dimensional material nanosheet.

Drawings

FIG. 1 is a scanning electron microscope picture of boron nitride nanosheets prepared in example 1;

fig. 2 is a scanning electron microscope image of graphene nanoplatelets prepared in example 2;

FIG. 3 is the MoS prepared in example 3₂Scanning electron microscope images of the nanosheets;

fig. 4 is a scanning electron microscope image of the boron nitride nanosheet prepared in comparative example 2.

Detailed Description

The technical solution of the present invention will be described in further detail with reference to the accompanying drawings and specific examples. The following examples, which are intended to illustrate and explain the technical solution of the present invention by using different two-dimensional materials for peeling, will be better understood from the following examples. However, those skilled in the art will readily appreciate that the specific material ratios, process conditions and results thereof described in the examples are merely illustrative of the present invention and should not, nor should they, limit the scope of the invention as detailed in the claims.

The raw materials used in the invention are as follows:

hexagonal boron nitride, the english name Hexagonal boron nitride, abbreviated as h-BN, available from dengdong riken technologies ltd;

natural flake graphite, purchased from Qingdaoshengda graphite Limited;

molybdenum disulfide, British name Molybdenum (IV) sulfide, chemical formula is MoS₂From Shanghai Michelin Biochemical technology, Inc.;

n, N-diethyl-3-methylbenzamide, also known as DEET, having the name Diethyltoluamide, abbreviated DEET, and available from Shanghai Tantaceae technologies, Inc.;

isopropyl alcohol, the english name Iso-Propyl alcohol, abbreviated IPA, available from shanghai tanacetaceae technologies ltd;

n, N-Dimethylformamide, the english name N, N-Dimethylformamide, abbreviated DMF, available from shanghai taitataceae technologies gmbh;

n-methylpyrrolidone, the English name N-methyl-2-pyrollidone, abbreviated NMP, available from Shanghai Tantake Technology, Inc.;

ethanol, the english name Ethanol, abbreviated ET, was purchased from shanghai tamatake technologies gmbh.

Examples 1 to 4 and comparative examples 1 to 3

The raw materials and the proportions used in the examples and comparative examples of the present invention are shown in table 1 below:

TABLE 1

Adding the two-dimensional materials into corresponding solvents according to the mixture ratio shown in Table 1, and carrying out ultrasonic treatment for 24 hours at intervals of 5s and 1s by using an ultrasonic cell disruptor at the power of 200W; and centrifuging the ultrasonic dispersion liquid at 2000rpm for 15min, removing the non-stripped two-dimensional material, centrifuging the supernatant at 10000rpm for 15min, and drying overnight to obtain the corresponding two-dimensional material nanosheets.

Analysis by scanning Electron microscope

Scanning electron microscope analysis is carried out by taking the two-dimensional material nanosheets obtained in the embodiments 1-3 and the comparative example 2 as an example, the model of the scanning electron microscope used in the invention is SEM and Hitachi S-4800, the parameter is set to be 2KV, and the magnification is 10-25K. The scanning electron microscope analysis results are as follows:

FIG. 1 shows a scanning electron microscope image of the boron nitride nanosheets prepared in example 1, from which it can be seen that large, thin boron nitride nanosheets having a lateral dimension of 1-3 μm, with 60% of the boron nitride nanosheets having a lateral dimension of 3 μm, are obtained. The edge of the boron nitride nanosheet is curled, the thickness is about 1-4nm, 40% of 3-8 layers and 60% of 9-12 layers. The size and thickness of the boron nitride nanosheet obtained by stripping are important indexes for evaluating the boron nitride nanosheet, and the boron nitride nanosheet obtained by the embodiment is large in size and thin in thickness, and is a high-quality boron nitride nanosheet.

As shown in fig. 2, which is a scanning electron microscope picture of the graphene nanoplatelets prepared in example 2, it can be seen that large and thin graphene nanoplatelets with lateral dimensions of 2-3 μm and 60% of graphene sheets with lateral dimensions of 3 μm are obtained. The edge of the graphene nanosheet is curled, and the graphene nanosheet is provided with upright graphene sheets, and the thickness of the graphene sheets is about 1-4 nm. 50% of the 3-8 layers and 50% of the 9-12 layers. The size and thickness of the graphene sheet obtained by stripping are important indexes for evaluating the graphene nanosheet, and the graphene sheet obtained by the embodiment is large in size and thin in thickness and is a high-quality graphene sheet.

FIG. 3 shows the MoS prepared in example 3₂Scanning electron microscope pictures of the nanosheets show that large and thin MoS is obtained₂Nanosheets having a transverse dimension of 200-500nm and 30% MoS₂The transverse size of the nano-sheet is 500 nm. The MoS₂Nanosheet edge generationCurly, with standing MoS₂The nano-sheet exists, the thickness is about 1-3nm, 30% of 1-2 layers and 70% of 3-5 layers. MoS obtained by exfoliation₂The size and thickness of the nanosheets are evaluated for MoS₂Important index of nanosheet, MoS obtained in this example₂The nano-sheet has larger size and thinner thickness, and is a high-quality MoS₂Nanosheets.

In addition, example 4 also yielded large, thin boron nitride nanoplates with lateral dimensions of 1-5 μm, with 40% of the boron nitride nanoplates having a lateral dimension of 3 μm. The edge of the boron nitride nanosheet is curled, the boron nitride nanosheet is erected, the thickness of the boron nitride nanosheet is about 1-5nm, 45% of 3-8 layers and 55% of 9-12 layers, and the boron nitride nanosheet is high-quality.

Example 5 also yielded large, thin boron nitride nanoplates with lateral dimensions of 1-3 μm, with 50% of the boron nitride nanoplates having a lateral dimension of 3 μm. The edge of the boron nitride nanosheet is curled, the boron nitride nanosheet is erected, the thickness of the boron nitride nanosheet is about 1-5nm, 60% of 3-8 layers and 40% of 9-12 layers are formed, and the boron nitride nanosheet is high-quality.

The boron nitride nanosheets obtained in comparative example 1 have a lateral dimension of 3-5 μm, and about 20-30% of the boron nitride nanosheets have a lateral dimension of 5 μm. The edge of the boron nitride nanosheet is curled, the boron nitride nanosheet is erected, the thickness is 1-5nm, 20% of 3-8 layers and 80% of 9-12 layers exist.

The boron nitride nanoplates obtained in comparative example 2, as shown in fig. 4, had lateral dimensions of 1-3 μm, and about 20% of the boron nitride nanoplates had lateral dimensions of 3 μm. The edge of the boron nitride nanosheet is curled, the upright boron nitride nanosheet exists, the thickness is 1-5nm, 22% of 3-8 layers and 78% of 9-12 layers are formed.

The boron nitride nanoplatelets obtained in comparative example 3 have a lateral dimension of 1-3 μm, and about 20-30% of the boron nitride nanoplatelets have a lateral dimension of 3 μm. The edge of the boron nitride nanosheet is curled, the boron nitride nanosheet is erected, the thickness is 1-5nm, 15% of 3-8 layers and 85% of 9-12 layers exist.

Combining the experimental results of examples 1-5 and comparative examples 1-3, it can be seen that the ultrasonic peeling of two-dimensional material using DEET and its mixed solution with isopropanol or ethanol has high yield, especially much higher than the ultrasonic effect of conventional DMF, IPA, NMP, and the results of examples 1, 2, 3 show that DEET is universal for two-dimensional material and has 40% peeling yield, and improves production yield. The conventional solvent used in example 1 in comparative examples 1, 2 and 3 has a better stripping efficiency, and at the highest, it can have nearly three times of efficiency improvement. Examples 4 and 5 demonstrate that even when DEET is mixed, it still has a high stripping efficiency.

In summary, the method for preparing the two-dimensional material nanosheet by DEET stripping provided by the invention adopts DEET as a stripping solvent, and the obtained product is a large and thin nanosheet, and compared with the traditional solvent stripping, the method has a better stripping effect, and especially makes more obvious progress in the size distribution breadth and the stripping efficiency. Meanwhile, DEET used in the method is commonly used for preparing the efficient nontoxic mosquito repellent, is a relatively bio-friendly solvent, has better effect than the conventional solvent, and is more widely applicable to materials.

The above description is only of the preferred embodiments of the present invention, and it should be noted that: it will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the principles of the invention and these are intended to be within the scope of the invention.