阅读说明：本技术 一种高浓度高分散性的超薄二硫化钼分散液及其制备方法 (High-concentration high-dispersibility ultrathin molybdenum disulfide dispersion liquid and preparation method thereof ) 是由 宋浩杰 田瑞 杨进 王思哲 李永 贾晓华 于 2020-12-23 设计创作，主要内容包括：本发明公开一种高浓度高分散性的超薄二硫化钼分散液及其制备方法,以二硫化钼为原料、离子液晶为辅助剂,按特定比例分散于去离子水中,采用超声的方式制备出水基高浓度高分散性的超薄二硫化钼分散液,制备的二硫化钼分散液能够在常温条件下长期稳定保存,制备工艺简单高效,生产周期短,适用于大规模生产；采用水为溶剂制得的二硫化钼表面不会残存有机物,生产成本低,绿色环保,安全系数高,不会破坏二硫化钼的晶体结构,具有很高的应用价值。(The invention discloses a high-concentration high-dispersibility ultrathin molybdenum disulfide dispersion liquid and a preparation method thereof, wherein molybdenum disulfide is used as a raw material, ionic liquid crystal is used as an auxiliary agent, the molybdenum disulfide is dispersed in deionized water according to a specific proportion, and a water-based high-concentration high-dispersibility ultrathin molybdenum disulfide dispersion liquid is prepared in an ultrasonic mode; the molybdenum disulfide surface that adopts water to make as the solvent can not remain the organic matter, low in production cost, green, factor of safety is high, can not destroy molybdenum disulfide's crystal structure, has very high using value.)

1. The method for preparing the ultra-thin molybdenum disulfide dispersion liquid with high concentration and high dispersibility is characterized by comprising the following steps:

(1) adding ionic liquid crystal into deionized water, and stirring until the ionic liquid crystal is fully dissolved to obtain an ionic liquid crystal solution with the concentration of 2.5-20 mg/mL;

(2) adding molybdenum disulfide powder into the solution prepared in the step (1), wherein the mass ratio of the molybdenum disulfide powder to the ionic liquid crystal in the step (1) is (1-5): 1, stirring until the mixture is uniformly dispersed to obtain a mixed solution of molybdenum disulfide and ionic liquid crystal;

(3) carrying out ultrasonic stripping treatment on the molybdenum disulfide and ionic liquid crystal mixed solution obtained in the step (2) in a water bath manner;

(4) and (4) carrying out centrifugal separation treatment on the solution obtained by ultrasonic treatment in the step (3), and taking two thirds of the upper-layer dispersion liquid to obtain the ultrathin molybdenum disulfide dispersion liquid.

2. The method of claim 1, wherein the ultra-thin molybdenum disulfide dispersion with high concentration and high dispersibility is prepared by: the ionic liquid crystal used in the step (1) is 1-hexadecyl-3-methylimidazole bromide, 1-hexadecyl-3-methylimidazole tetrafluoroborate, 1-hexadecyl-3-methylimidazole hexafluorophosphate, 1-hexadecyl-3-methylimidazole chloride, 1-dodecyl-3-methylimidazole bromide or 1-dodecyl-3-methylimidazole chloride.

3. The method of claim 1, wherein the ultra-thin molybdenum disulfide dispersion with high concentration and high dispersibility is prepared by: the particle size of the molybdenum disulfide powder in the step (2) is 1-2 mu m.

4. The method of claim 1, wherein the ultra-thin molybdenum disulfide dispersion with high concentration and high dispersibility is prepared by: the ultrasonic power in the step (3) is 100-500W, and the ultrasonic time is 10-60 min.

5. The method of claim 1, wherein the ultra-thin molybdenum disulfide dispersion with high concentration and high dispersibility is prepared by: the rotating speed of centrifugal separation in the step (4) is 2000-5000 rpm, and the centrifugal time is 5-30 min.

6. A highly concentrated and highly dispersible ultra-thin molybdenum disulfide dispersion prepared by the process according to any one of claims 1 to 5.

Technical Field

The invention belongs to the field of chemical industry, and relates to a high-concentration high-dispersibility ultrathin molybdenum disulfide dispersion liquid and a preparation method thereof.

Background

Molybdenum disulfide (MoS)₂) Transition metal sulfides, which are graphene-like layered structures, have attracted considerable attention in recent years. The molybdenum disulfide belongs to a layered crystal structure of a hexagonal system, each crystalThe molybdenum disulfide sandwich-like structure is composed of a plurality of molybdenum disulfide molecular layers, and the single-layer molybdenum disulfide is an S-Mo-S-shaped sandwich-like structure formed by two sulfur atomic layers and one molybdenum atomic layer. Two adjacent molecular layers are connected through weak van der waals force, the distance between the molecular layers is 0.65nm, and the molecular layers are connected through strong chemical bonds, so that the preparation of single-layer or few-layer molybdenum disulfide nanosheets is possible by overcoming the van der waals force to strip. Compared with the original molybdenum disulfide, the single-layer or few-layer molybdenum disulfide nanosheet has excellent physicochemical properties, so that the molybdenum disulfide nanosheet has a wide application prospect, but the prepared molybdenum disulfide is easy to curl and agglomerate, so that the molybdenum disulfide is limited in dispersion in a water environment, and the application of the molybdenum disulfide in the water environments such as photocatalysis, water treatment, biomedicine, membrane technology, seawater desalination and the like is limited to a great extent.

Currently, the preparation method of molybdenum disulfide mainly comprises hydrothermal synthesis, chemical vapor deposition, mechanical stripping, ion intercalation and liquid phase stripping. Patent 201510042763.7 discloses a method for preparing highly dispersible nano molybdenum disulfide dispersion under protection of liquid nitrogen or dry ice, which comprises preparing expandable molybdenum disulfide by n-butyl lithium intercalation under protection of liquid nitrogen or dry ice, performing lithium intercalation expansion nano molybdenum disulfide, ultrasonic hydrolysis, and high-temperature heat treatment to obtain highly dispersible two-dimensional nano molybdenum disulfide particles, and performing ultrasonic dispersion in organic solvent to obtain highly dispersible nano molybdenum disulfide dispersion. Although the method can prepare the high-dispersity molybdenum disulfide dispersion liquid, the method is only limited to organic solvents, the preparation process is complicated, the method is not suitable for industrial production, and the application of the method in water environment is limited to a great extent.

The patent 201811468304.5 discloses a molybdenum disulfide stripping method, molybdenum disulfide prepared by the method and application of the molybdenum disulfide, and the molybdenum disulfide dispersion is obtained by mixing molybdenum disulfide powder, water and a surfactant, carrying out ultrasonic treatment for 8-20 h, and carrying out centrifugal separation. The surfactant used in the method has a hydrophilic group and a hydrophobic group, the hydrophobic group can be stably combined with the molybdenum disulfide, and the hydrophilic group enables the molybdenum disulfide to be stably dispersed in water. Although the method can prepare the molybdenum disulfide which is stably dispersed in water, the structural defects of the molybdenum disulfide nanosheets can be caused by long-time ultrasonic and energy consumption, and the prepared molybdenum disulfide dispersion liquid has low concentration (50 mg/L).

Therefore, the need exists in the art to develop a simple, efficient and green method for preparing high-concentration and high-dispersibility molybdenum disulfide dispersion liquid, and the method is easy to expand and can be used for industrial production, and the prepared molybdenum disulfide dispersion liquid can meet the requirements of various fields.

Disclosure of Invention

The invention aims to provide the high-concentration high-dispersity ultrathin molybdenum disulfide dispersion liquid and the preparation method thereof, the preparation method is simple, the prepared molybdenum disulfide dispersion liquid can be stably stored for a long time at normal temperature, and the crystal structure of molybdenum disulfide subjected to ionic liquid crystal auxiliary stripping is not damaged.

In order to achieve the above object, the present invention adopts the following technical solutions.

The method for preparing the ultra-thin molybdenum disulfide dispersion liquid with high concentration and high dispersibility comprises the following steps:

(1) adding ionic liquid crystal into deionized water, and stirring until the ionic liquid crystal is fully dissolved to obtain an ionic liquid crystal solution with the concentration of 2.5-20 mg/mL;

(2) adding molybdenum disulfide powder into the solution prepared in the step (1), wherein the mass ratio of the molybdenum disulfide powder to the ionic liquid crystal in the step (1) is (1-5): 1, stirring until the mixture is uniformly dispersed to obtain a mixed solution of molybdenum disulfide and ionic liquid crystal;

(3) carrying out ultrasonic stripping treatment on the molybdenum disulfide and ionic liquid crystal mixed solution obtained in the step (2) in a water bath manner;

(4) and (4) carrying out centrifugal separation treatment on the solution obtained by ultrasonic treatment in the step (3), and taking two thirds of the upper-layer dispersion liquid to obtain the ultrathin molybdenum disulfide dispersion liquid.

Further, the ionic liquid crystal used in the step (1) is 1-hexadecyl-3-methylimidazole bromide, 1-hexadecyl-3-methylimidazole tetrafluoroborate, 1-hexadecyl-3-methylimidazole hexafluorophosphate, 1-hexadecyl-3-methylimidazole chloride, 1-dodecyl-3-methylimidazole bromide or 1-dodecyl-3-methylimidazole chloride.

Further, the particle size of the molybdenum disulfide powder in the step (2) is 1-2 μm.

Further, the ultrasonic power in the step (3) is 100-500W, and the ultrasonic time is 10-60 min.

Further, the rotation speed of centrifugal separation in the step (4) is 2000-5000 rpm, and the centrifugal time is 5-30 min.

The invention has the following beneficial effects:

according to the invention, the solvent adopted in the process of stripping the molybdenum disulfide is water, other organic solvents are not needed, and organic matters can not remain on the surface of the molybdenum disulfide prepared by adopting water as the solvent, so that the production cost is low, the environment is protected, and the safety factor is high; the ionic liquid crystal is used as an auxiliary agent for stripping and stable dispersion, so that the dispersibility of molybdenum disulfide in water can be improved, the stripping is more thorough, the stripped molybdenum disulfide can be stably dispersed in an aqueous solution and can be stored at room temperature for 8 months, the concentration of the molybdenum disulfide can reach 7.85mg/mL, and the technical problem of poor stability of the molybdenum disulfide nanosheet in a water environment is solved.

According to the invention, through ionic liquid crystal auxiliary stripping, the water-based high-concentration high-dispersibility ultrathin molybdenum disulfide dispersion liquid is prepared in an ultrasonic mode under a certain power, the physical and chemical properties of molybdenum disulfide cannot be changed, the crystal structure of molybdenum disulfide cannot be damaged, and the application value is very high.

According to the invention, molybdenum disulfide is used as a raw material, ionic liquid crystal is used as an auxiliary agent, the molybdenum disulfide is dispersed in deionized water according to a specific proportion, a water-based high-concentration high-dispersibility ultrathin molybdenum disulfide dispersion liquid is prepared in an ultrasonic mode, the prepared molybdenum disulfide dispersion liquid can be stably stored for a long time under a normal temperature condition, the preparation process is simple and efficient, the production period is short, and the preparation method is suitable for large-scale production.

Drawings

FIG. 1 is a transmission electron micrograph of highly dispersed molybdenum disulfide prepared in example 4;

FIG. 2 is a photomicrograph of a highly dispersed molybdenum disulfide dispersion prepared in example 4;

FIG. 3 is a UV spectrum of a highly dispersed molybdenum disulfide dispersion prepared in example 4;

FIG. 4 is a photograph of a dispersion of a highly dispersed molybdenum disulfide dispersion prepared in example 4;

figure 5 is a photomicrograph of a 8 month exposure of the highly dispersed molybdenum disulfide dispersion prepared in example 4.

Detailed Description

The present invention will be described in further detail with reference to the following examples, which are not intended to limit the invention thereto.

Example 1

(1) Weighing 50mg of ionic liquid crystal-brominated 1-hexadecyl-3-methylimidazole, adding the ionic liquid crystal-brominated 1-hexadecyl-3-methylimidazole into 20mL of deionized water, and stirring the mixture strongly until the mixture is fully dissolved in the water to obtain an ionic liquid crystal aqueous solution (the concentration is 2.5mg/mL) for stripping molybdenum disulfide;

(2) weighing 0.05g of molybdenum disulfide powder, adding the molybdenum disulfide powder into the ionic liquid crystal solution, and stirring until the molybdenum disulfide powder is uniformly dispersed to obtain a mixed solution of molybdenum disulfide and ionic liquid crystal;

(3) carrying out ultrasonic treatment on the molybdenum disulfide and ionic liquid crystal mixed solution for 20min, wherein the ultrasonic power is 100W, and the frequency is 40 KHz;

(4) carrying out centrifugal separation treatment on the molybdenum disulfide dispersion liquid subjected to ultrasonic treatment by a centrifugal machine, wherein the centrifugal speed is 2000rpm, and the centrifugal time is 30 min;

(5) after centrifugal treatment, taking two thirds of clear liquid at the upper layer to obtain the high-dispersity molybdenum disulfide dispersion liquid, and determining the concentration of the dispersion liquid to be 2.23mg/mL through ultraviolet spectrum.

Example 2

(1) Weighing 100mg of ionic liquid crystal-1-hexadecyl-3-methylimidazolium tetrafluoroborate, adding the ionic liquid crystal-1-hexadecyl-3-methylimidazolium tetrafluoroborate into 20mL of deionized water, and stirring the mixture strongly until the mixture is fully dissolved in the water to obtain an ionic liquid crystal aqueous solution (the concentration is 5mg/mL) for stripping molybdenum disulfide;

(2) weighing 0.5g of molybdenum disulfide powder, adding the molybdenum disulfide powder into the ionic liquid crystal solution, and stirring until the molybdenum disulfide powder is uniformly dispersed to obtain a mixed solution of molybdenum disulfide and ionic liquid crystal;

(3) carrying out ultrasonic treatment on the molybdenum disulfide and ionic liquid crystal mixed solution for 30min, wherein the ultrasonic power is 200W, and the frequency is 40 KHz;

(4) carrying out centrifugal separation treatment on the molybdenum disulfide dispersion liquid subjected to ultrasonic treatment by a centrifugal machine, wherein the centrifugal speed is 2000rpm, and the centrifugal time is 30 min;

(5) after centrifugal treatment, taking two thirds of clear liquid at the upper layer to obtain the high-dispersity molybdenum disulfide dispersion liquid, and determining the concentration of the dispersion liquid to be 3.45mg/mL through ultraviolet spectrum.

Example 3

(1) Weighing 200mg of ionic liquid crystal-1-hexadecyl-3-methylimidazolium hexafluorophosphate, adding the ionic liquid crystal-1-hexadecyl-3-methylimidazolium hexafluorophosphate into 20mL of deionized water, and stirring strongly until the ionic liquid crystal-1-hexadecyl-3-methylimidazolium hexafluorophosphate is fully dissolved in the water to obtain an ionic liquid crystal aqueous solution (the concentration is 10mg/mL) for stripping molybdenum disulfide;

(2) weighing 1g of molybdenum disulfide powder, adding the molybdenum disulfide powder into the ionic liquid crystal solution, and stirring until the molybdenum disulfide powder is uniformly dispersed to obtain a mixed solution of molybdenum disulfide and ionic liquid crystal;

(3) carrying out ultrasonic treatment on the molybdenum disulfide and ionic liquid crystal mixed solution for 40min, wherein the ultrasonic power is 300W, and the frequency is 40 KHz;

(4) carrying out centrifugal separation treatment on the molybdenum disulfide dispersion liquid subjected to ultrasonic treatment by a centrifugal machine, wherein the centrifugal speed is 3000rpm, and the centrifugal time is 20 min;

(5) after centrifugal treatment, taking two thirds of clear liquid at the upper layer to obtain the high-dispersity molybdenum disulfide dispersion liquid, and determining the concentration of the dispersion liquid to be 5.28mg/mL through ultraviolet spectrum.

Example 4

(1) Weighing 300mg of ionic liquid crystal-chlorinated 1-hexadecyl-3-methylimidazole, adding the ionic liquid crystal-chlorinated 1-hexadecyl-3-methylimidazole into 20mL of deionized water, and stirring the mixture strongly until the mixture is fully dissolved in the water to obtain an ionic liquid crystal aqueous solution (the concentration is 15mg/mL) for stripping molybdenum disulfide;

(2) weighing 1.5g of molybdenum disulfide powder, adding the molybdenum disulfide powder into the ionic liquid crystal solution, and stirring until the molybdenum disulfide powder is uniformly dispersed to obtain a mixed solution of molybdenum disulfide and ionic liquid crystal;

(3) carrying out ultrasonic treatment on the molybdenum disulfide and ionic liquid crystal mixed solution for 30min, wherein the ultrasonic power is 500W, and the frequency is 40 KHz;

(4) carrying out centrifugal separation treatment on the molybdenum disulfide dispersion liquid subjected to ultrasonic treatment by a centrifugal machine, wherein the centrifugal speed is 4000rpm, and the centrifugal time is 30 min;

(5) after centrifugal treatment, taking two thirds of clear liquid at the upper layer to obtain the high-dispersity molybdenum disulfide dispersion liquid, and determining the concentration of the dispersion liquid to be 7.16mg/mL through ultraviolet spectrum.

As shown in fig. 1, a transmission electron micrograph of the highly dispersed molybdenum disulfide prepared in example 4 shows that the prepared molybdenum disulfide is uniformly dispersed and has a size of about 100 nm;

as shown in fig. 2, which is a macroscopic photograph of the highly dispersed molybdenum disulfide dispersion prepared in example 4, it can be seen that the prepared molybdenum disulfide dispersion has a dark green color;

as shown in fig. 3, which is an ultraviolet spectrum of the highly dispersed molybdenum disulfide dispersion prepared in example 4, it can be seen that there are two characteristic peaks at 615 and 670nm, which are attributed to the transition of B exciton and a exciton of 2H type molybdenum disulfide at K point in brillouin region;

as shown in fig. 4, a photograph of the dispersion of the highly dispersed molybdenum disulfide dispersion prepared in example 4 shows that the molybdenum disulfide prepared has excellent dispersibility and good water solubility;

referring to fig. 5, a macro-photograph of the highly dispersed molybdenum disulfide dispersion prepared in example 4 after being left for 8 months, it can be seen from the macro-photograph that the color of the molybdenum disulfide dispersion after being left for 8 months has not changed, which indicates that the prepared molybdenum disulfide dispersion has good dispersion stability.

Example 5

(1) Weighing 300mg of ionic liquid crystal-brominated 1-dodecyl-3-methylimidazole, adding into 20mL of deionized water, and stirring strongly until the ionic liquid crystal-brominated 1-dodecyl-3-methylimidazole is fully dissolved in the water to obtain an ionic liquid crystal aqueous solution (the concentration is 15mg/mL) for stripping molybdenum disulfide;

(2) weighing 2g of molybdenum disulfide powder, adding the molybdenum disulfide powder into the ionic liquid crystal solution, and stirring until the molybdenum disulfide powder is uniformly dispersed to obtain a mixed solution of molybdenum disulfide and ionic liquid crystal;

(3) carrying out ultrasonic treatment on the molybdenum disulfide and ionic liquid crystal mixed solution for 30min, wherein the ultrasonic power is 500W, and the frequency is 40 KHz;

(4) carrying out centrifugal separation treatment on the molybdenum disulfide dispersion liquid subjected to ultrasonic treatment by a centrifugal machine, wherein the centrifugal speed is 3000rpm, and the centrifugal time is 30 min;

(5) after centrifugal treatment, taking two thirds of clear liquid at the upper layer to obtain the high-dispersity molybdenum disulfide dispersion liquid, and determining the concentration of the dispersion liquid to be 7.85mg/mL through ultraviolet spectrum.

Example 6

(1) Weighing 400mg of ionic liquid crystal-chlorinated 1-dodecyl-3-methylimidazole, adding into 20mL of deionized water, and stirring strongly until the ionic liquid crystal-chlorinated 1-dodecyl-3-methylimidazole is fully dissolved in the water to obtain an ionic liquid crystal aqueous solution (the concentration is 20mg/mL) for stripping molybdenum disulfide;

(2) weighing 2g of molybdenum disulfide powder, adding the molybdenum disulfide powder into the ionic liquid crystal solution, and stirring until the molybdenum disulfide powder is uniformly dispersed to obtain a mixed solution of molybdenum disulfide and ionic liquid crystal;

(3) carrying out ultrasonic treatment on the molybdenum disulfide and ionic liquid crystal mixed solution for 60min, wherein the ultrasonic power is 500W, and the frequency is 40 KHz;

(4) carrying out centrifugal separation treatment on the molybdenum disulfide dispersion liquid subjected to ultrasonic treatment by a centrifugal machine, wherein the centrifugal speed is 5000rpm, and the centrifugal time is 10 min;

after centrifugal treatment, taking two thirds of clear liquid at the upper layer to obtain the high-dispersity molybdenum disulfide dispersion liquid, and determining the concentration of the dispersion liquid to be 7.24mg/mL through ultraviolet spectrum.

Example 7

(1) Weighing 400mg of ionic liquid crystal-chlorinated 1-dodecyl-3-methylimidazole, adding into 20mL of deionized water, and stirring strongly until the ionic liquid crystal-chlorinated 1-dodecyl-3-methylimidazole is fully dissolved in the water to obtain an ionic liquid crystal aqueous solution (the concentration is 20mg/mL) for stripping molybdenum disulfide;

(2) weighing 2g of molybdenum disulfide powder, adding the molybdenum disulfide powder into the ionic liquid crystal solution, and stirring until the molybdenum disulfide powder is uniformly dispersed to obtain a mixed solution of molybdenum disulfide and ionic liquid crystal;

(3) carrying out ultrasonic treatment on the molybdenum disulfide and ionic liquid crystal mixed solution for 10min, wherein the ultrasonic power is 500W, and the frequency is 40 KHz;

(4) carrying out centrifugal separation treatment on the molybdenum disulfide dispersion liquid subjected to ultrasonic treatment by a centrifugal machine, wherein the centrifugal speed is 5000rpm, and the centrifugal time is 5 min;

after centrifugal treatment, taking two thirds of clear liquid at the upper layer to obtain the high-dispersity molybdenum disulfide dispersion liquid, and determining the concentration of the dispersion liquid to be 7.24mg/mL through ultraviolet spectrum.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which is to be covered by the claims.