CN108658128B

CN108658128B - Preparation method of MoS2 micro nanospheres with hierarchical structure

Info

Publication number: CN108658128B
Application number: CN201810873431.7A
Authority: CN
Inventors: 王开新; 韩成良; 周正; 赵世维; 卞正东
Original assignee: Hefei Zhonghang Nanometer Technology Development Co ltd
Current assignee: Hefei Zhonghang Nanometer Technology Development Co ltd
Priority date: 2018-08-02
Filing date: 2018-08-02
Publication date: 2020-05-05
Anticipated expiration: 2038-08-02
Also published as: CN108658128A

Abstract

MoS with hierarchical structure₂A preparation method of micro-nano spheres relates to the technical field of preparation of micro-nano structure materials. By hydrothermal reactionMoS with hierarchical structure should be prepared₂Adding a sulfur source and a molybdenum source into a Polyacrylamide (PAM) aqueous solution at room temperature, and uniformly stirring to obtain a reaction precursor solution; the reaction precursor solution is transferred into a reaction kettle for hydrothermal reaction to obtain MoS₂And (3) micro-nano structure materials. According to the invention, the MoS with the hierarchical structure is successfully prepared by using thioacetamide or thiourea as a sulfur source, sodium molybdate or ammonium molybdate as a molybdenum source and a Polyacrylamide (PAM) template control agent through a simple hydrothermal method₂Micro-nano spheres. The invention realizes MoS₂Shaping of the particles into hierarchically structured MoS₂The preparation of the material provides a new method. The preparation method has the advantages of simple operation, low cost and large amount of obtained products.

Description

MoS with hierarchical structure2Preparation method of micro-nano sphere

Technical Field

The invention relates to the technical field of preparation of micro-nano structure materials, in particular to a MoS with a hierarchical structure₂A method for preparing micro-nano spheres.

Background

Nano-scale narrow bandgap MoS₂(E_g1.29eV) has the same layered structure as graphene, and has the advantages of stable chemical performance, high specific surface area, good catalytic performance and the like. The unique physical and chemical properties of the MoS₂The catalyst is widely applied to the aspects of lubrication field, catalysis field, electrochemistry field and the like.

Nano MoS₂The preparation method of (2) mainly comprises a physical method and a hydrothermal method. The physical method is to use mechanical grinding and high-energy physics to carry out MoS on the block₂Pulverizing and refining to obtain nano-scale MoS₂. The hydrothermal method generally uses thiourea, molybdate and the like as raw materials to prepare the nano MoS₂. The two methods each have special features and advantages and disadvantages. Preparation of nano MoS by physical method₂The powder has the advantages of simple principle, high yield and the like, but the method has higher energy consumption and can obtain the powderMoS of (1)₂The shape of the particles is difficult to control. Nano MoS obtained by hydrothermal method₂Morphology is generally more regular, but some incorporation of morphology control agents is required. The micro-nano structure material has larger size and stability, so the micro-nano structure material is easy to disperse and separate in the using process. Meanwhile, the micro-nano structure material is provided with a plurality of nano structure units, so that the micro-nano structure material has some nano effects. Therefore, the micro-nano structure material has the advantages of a micron-sized material and a nano material, and in recent years, material researchers have studied and reported a lot of various micro-nano structure materials.

Polyacrylamide (PAM) is a linear water-soluble high molecular polymer that is commonly used as an effective flocculant, thickener, paper strengthening agent, and liquid drag reducer, and is widely used in the fields of water treatment, paper making, petrochemical industry, and the like. The invention takes Polyacrylamide (PAM) as a molecular template, Thioacetamide (TAA) or thiourea and molybdate (Na)₂MoO₄·2H₂O or (NH)₄)₂MoO₄·2H₂O) is used as a raw material, and a simple hydrothermal method is adopted to successfully prepare MoS with a hierarchical structure₂Micro-nano spheres. The method has the advantages of less used raw materials, low cost, controllable shape of the obtained product and the like, and is expected to be used for practical production.

Disclosure of Invention

The invention aims at the existing preparation of some nano MoS₂The defects in the technology are that MoS with a hierarchical structure is successfully obtained in one step by a hydrothermal method in an aqueous solution system consisting of a sulfur source, a molybdenum source and Polyacrylamide (PAM)₂Micro-nano spheres. The method has the advantages of simple operation, low cost, environmental protection and the like, and is used for preparing the MoS with the hierarchical structure₂An easy method is provided.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows: MoS with hierarchical structure₂The preparation method of the micro-nano sphere comprises the steps of taking thioacetamide or thiourea as a sulfur source, sodium molybdate or ammonium molybdate as a molybdenum source, taking Polyacrylamide (PAM) as a template control agent, and preparing MoS with a hierarchical structure by adopting a hydrothermal reaction₂Micro-nano spheres.

As a preferred technical scheme of the preparation method, the preparation method comprises two processes of preparation of reaction precursor liquid and hydrothermal reaction, and comprises the following specific steps:

1) adding 2-4 g of sulfur source and 0.2-0.6 g of molybdenum source into 100mL of Polyacrylamide (PAM) aqueous solution with the concentration of 0.1-3g/L at room temperature, and uniformly stirring to obtain reaction precursor liquid;

2) transferring the reaction precursor solution into a reaction kettle to perform hydrothermal reaction for 6-48 hours at 180-200 ℃ to obtain MoS₂And (3) micro-nano structure materials.

In the preparation method, in CH₄N₂S-MoO₄ ^2--PAM-H₂In an O reaction system, MoS with regular morphology is obtained after hydrothermal reaction₂And (3) microspheres. In CH₃CSNH₂-MoO₄ ^2--PAM-H₂In an O reaction system, MoS with higher sphericity can be obtained after hydrothermal reaction₂And (3) microspheres.

According to the invention, the MoS with the hierarchical structure is successfully prepared by using thioacetamide or thiourea as a sulfur source, sodium molybdate or ammonium molybdate as a molybdenum source and a Polyacrylamide (PAM) template control agent through a simple hydrothermal method₂Micro-nano spheres. Compared with the prior preparation method, the invention also has the following advantages:

1) the invention realizes MoS₂Shaping of the particles into hierarchically structured MoS₂The preparation of the material provides a new method.

2) The method has the advantages of simple operation, low cost and large amount of obtained products.

Drawings

FIG. 1 is a morphological, chemical composition and structural analysis of the product obtained in example 1;

FIG. 2 is a graph showing the effect of different amounts of Polyacrylamide (PAM) on the morphology of the product in example 2;

FIG. 3 is a graph showing the effect of different reaction times on the morphology of the product in example 3.

Detailed Description

The invention is characterized by the following classification in connection with the examples and the figuresMoS of structure₂The preparation method of the micro-nano sphere is further detailed. The structure and morphological properties of the product obtained by the method are respectively characterized and analyzed by X-ray powder diffraction (XRD, D3500) and a field emission scanning electron microscope (FE-SEM, SU 8010).

Example 1

MoS with hierarchical structure₂Preparation and characterization of the micro-nanospheres:

the preparation method mainly comprises two processes of preparation of reaction precursor liquid and hydrothermal reaction, and comprises the following specific steps:

1) adding 3g of thioacetamide and 0.4g of sodium molybdate into 100mL of Polyacrylamide (PAM) aqueous solution with the concentration of 0.1g/L at room temperature, and uniformly stirring to obtain reaction precursor liquid;

2) transferring the reaction precursor solution into a reaction kettle to carry out hydrothermal reaction for 24 hours at 180 ℃ to obtain MoS₂And (3) micro-nano structure materials.

FIG. 1a is an SEM overall appearance of a prepared product molybdenum disulfide, and is a macroscopic distribution of molybdenum disulfide particles, and MoS obtained₂Mainly existing in a spherical form, and the obtained MoS₂The sphericity is very high, the agglomeration degree is relatively light, the particle size of the product is relatively uniform, when the obtained molybdenum disulfide microspheres are spread on a plane, a flat film can be obtained, and the method has a good application prospect in the lubrication field. By adding 0.1g/L Polyacrylamide (PAM), the sphericity of the molybdenum disulfide is greatly improved after 24 hours of reaction. In FIG. 1b, the particle size of the obtained molybdenum disulfide is about 1.5 μm, compared with the labeled particle size. The interior of the molybdenum disulfide has a layered structure and is formed by interweaving nano-order wrinkled sheets, the thickness of each sheet layer is about 5nm, and the particle size is uniform. In FIG. 1C, the composition of the single product is shown, and the lamellar structure is shown, and the main components of the microspheres are Mo, S and C. FIG. 1d is an X-ray diffraction pattern of molybdenum disulfide, indexed using standard powder diffraction card PDF # 170744.

Example 2

Different amounts of polyacrylamide to MoS₂Influence of particle morphology:

in this example, two experiments were carried out under the same conditions as in example 1, except that Polyacrylamide (PAM) was not added and an excessive amount of Polyacrylamide (PAM) was added (concentration: 3 g/L).

FIG. 2a shows the morphology of molybdenum disulfide obtained without Polyacrylamide (PAM), with irregular particle size, different shapes and serious agglomeration. When excessive Polyacrylamide (PAM) is added (with the concentration of 3g/L), spherical molybdenum disulfide can be obtained as shown in figure 2b, but the morphology of the obtained product is not very regular and cannot be expected. When the dosage of Polyacrylamide (PAM) is 0.01-0.3g/100mL, the obtained molybdenum disulfide has better morphological characteristics.

Based on the above experimental results, it can be considered that MoS₂The formation process of the microspheres is as follows: first, nano-layered MoS is generated in a reaction kettle₂And then, under the action of a Polyacrylamide (PAM) template, self-assembling to form the molybdenum disulfide micro/nanospheres. The above is represented by the formula (1).

Mo⁴⁺+2S^2-→MoS₂(1)

It is noted that a certain amount of Polyacrylamide (PAM) existing in the reaction system plays a role of a template, so that the layered molybdenum disulfide is assembled into micro-nanospheres to obtain MoS₂Micro-nano spheres.

Example 3

Different reaction time to MoS₂Influence of particle shape and size:

in the present example, three sets of experiments were performed, the hydrothermal reaction time was 12h, 24h, and 48h, respectively, and the other conditions were the same as in example 1.

Figure 3 illustrates primarily the variation of reaction time to explore the topographical features of molybdenum disulfide. The Polyacrylamide (PAM) concentration used was 0.01g/100 mL. FIG. 3a is an SEM image of the product obtained at a reaction time of 12h, from which molybdenum disulfide had spherical shape but had agglomeration phenomenon. And FIG. 3b is an SEM image of a product obtained by reacting for 24h, and the obtained product has uniform particle size, no agglomeration phenomenon and optimal effect. When the reaction time is 48h, as shown in fig. 3c, the shape of the molybdenum disulfide is still spherical, and a hollow sphere phenomenon occurs. Over an extended period of time, the layered structure will interlace into hollow spheres.

Based on the above experimental results, we believe that the morphology of molybdenum disulfide varies at different times. When the reaction time is 12 hours, the shapes of the molybdenum disulfide at this time are different in size and shape (see fig. 3 a). When the reaction time is 24 hours, the sphericity of the molybdenum disulfide is high (see fig. 3b), the particle size is uniform, and the reaction time is convenient. When the time is 48h, the molybdenum disulfide is still microspheres, but under the condition of overlong time, the MoS of the nano-layer sheet is increased₂A hollow phenomenon occurs when the molybdenum disulfide microspheres are stacked (see fig. 3 c). Therefore, the reaction time is preferably about 24 hours.

The foregoing is merely exemplary and illustrative of the principles of the present invention and various modifications, additions and substitutions of the specific embodiments described herein may be made by those skilled in the art without departing from the principles of the present invention or exceeding the scope of the claims set forth herein.

Claims

1. MoS with hierarchical structure₂The preparation method of the micro-nano sphere is characterized in that thioacetamide or thiourea is used as a sulfur source, sodium molybdate or ammonium molybdate is used as a molybdenum source, Polyacrylamide (PAM) is used as a template control agent, and the MoS with a hierarchical structure is prepared by adopting a hydrothermal reaction₂Micro-nanospheres, prepared MoS₂The particle size is 1.5 mu m, the inner part has a layered structure and is formed by interweaving nano-scale wrinkled sheets, and the thickness of each sheet layer is 5 nm;

the preparation method comprises two processes of preparation of reaction precursor liquid and hydrothermal reaction, and comprises the following steps:

2. The method of claim 1, wherein the compound is in CH₄N₂S-MoO₄ ^2--PAM-H₂In an O reaction system, MoS with regular morphology is obtained after hydrothermal reaction₂And (3) microspheres.

3. The method of claim 1, wherein the compound is in CH₃CSNH₂-MoO₄ ^2--PAM-H₂In an O reaction system, MoS with higher sphericity can be obtained after hydrothermal reaction₂And (3) microspheres.