Preparation method and application of few-layer metal phase molybdenum disulfide

Abstract

The invention belongs to the field of nano materials, and particularly relates to a preparation method and application of few-layer metal phase molybdenum disulfide. The preparation method of the few-layer metal phase molybdenum disulfide comprises the following steps that S1, a certain amount of thioacetamide, a certain amount of sodium molybdate dehydrate and a certain amount of intercalator sodium borohydride are weighed; adding the magneton into a mixed solution of deionized water and alcohol in different proportions, transferring into a polytetrafluoroethylene lining, then putting on a magnetic stirrer, stirring for preset time, taking out the magneton, transferring the polytetrafluoroethylene lining into a steel sleeve of a high-pressure reaction kettle, and completely sealing; s2, placing the high-pressure reaction kettle in a drying oven, modulating for preset time, and continuously reacting for several hours to obtain a precursor solution; the few-layer 1T-MoS2 synthesized by the method has the advantages of high yield and stable sample structure, and the method has the advantages of mild reaction conditions, wide applicability and cheap and easily available reaction raw materials, and lays a foundation for commercialization.

Description

Technical Field

[0001] The invention relates to the technical field of nanomaterials, and in particular to a preparation method of few-layer metal phase molybdenum disulfide and application thereof. Background Art

[0002] In the past few decades, supercapacitors, as a promising energy storage device, have attracted increasing attention due to their high power density and excellent cycle stability. The high capacitance of supercapacitors is an important parameter to achieve their high power, and the selection and design of electrode materials are feasible strategies to obtain high capacitance. Molybdenum disulfide (MoS2), as a typical two-dimensional material, has a unique layered structure and has been widely studied and applied in the field of electrochemistry. According to the different arrangements of Mo and S atoms, MoS2 has different phase structures, including an octahedral coordinated metal phase (1T-MoS2) and a triangular prism structured semiconductor phase (2H-MoS2).

[0003] Phase engineering can help MoS2 transform from a semiconductor phase to a metallic phase. Compared with 2H-MoS2, 1T-MoS2 has a larger interlayer spacing, higher conductivity and better hydrophilicity. The large interlayer spacing can shorten the diffusion path of ions in the electrolyte, allowing more ion intercalation and deintercalation. The high conductivity promotes rapid electron transport, and the good hydrophilicity promotes the ions in the electrolyte to contact the electrode material more easily. However, the high formation barrier and thermodynamic metastable properties make 1T-MoS2 difficult to synthesize, which hinders more research and wide application. There are many methods for preparing 1T-MoS2. In particular, hydrothermal synthesis, as one of the common methods for synthesizing and preparing nanomaterials, has the characteristics of high yield and low reaction temperature and is widely used in the synthesis of 1T-MoS2.

[0004] Moreover, as a layered material, the stacking of MoS2 layers seriously hinders the diffusion dynamics of ions, so obtaining a few-layer MoS2 can effectively shorten the ion diffusion path, expose more active sites, and increase the electronic state density at the Fermi level. Therefore, the few-layer 1T-MoS2 can significantly improve its electrochemical performance. Summary of the invention

[0005] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a preparation method of a few-layer metal phase molybdenum disulfide and its application, which has the characteristics of simple process, low cost, high yield, mild reaction and easy industrialization.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for preparing a few-layer metal phase molybdenum disulfide comprises the following steps:

[0008] S1: Weigh a certain amount of thioacetamide, sodium molybdate dihydrate and intercalation agent sodium borohydride, add them to a mixed solution of deionized water and alcohol in different proportions, transfer them into a polytetrafluoroethylene liner, then place them on a magnetic stirrer and stir for a preset time. After removing the magnet, move the polytetrafluoroethylene liner into the steel jacket of the high-pressure reactor and seal it completely;

[0009] S2: placing the high-pressure reactor in an oven for a preset time, and continuing the reaction for several hours to obtain a precursor solution;

[0010] S3: taking out the precursor solution after hydrothermal treatment, centrifuging it with water and ethanol for several times, and taking out the lower precipitate;

[0011] S4: Freeze-dry the lower precipitate for several hours, and the resulting sample is a few-layer 1T-MoS2 powder.

[0012] It should be noted that thioacetamide, sodium molybdate dihydrate and sodium borohydride are completely dissolved in a mixed solution of deionized water and ethanol, fully stirred, and transferred to a reactor containing a polytetrafluoroethylene liner, and placed in an oven. After being adjusted to a preset temperature, heating is continued for a certain time. After the reactor is naturally cooled to room temperature, the reactants are taken out, and a black product is obtained after being fully centrifuged and washed with deionized water and alcohol. Finally, the final product can be obtained by drying in a freeze dryer.

[0013] In a preferred embodiment, in step S1, the thioacetamide is 0.3-0.5 g, the sodium molybdate dihydrate is 0.3-0.5 g, the mass of the intercalation agent sodium borohydride is 0.2-0.4 g, the volume of deionized water added is 12 mL, and the volume of the alcohol solution is 2-8 mL.

[0014] It should be noted that the addition of alcohol can increase the vapor pressure of the closed environment of the reactor and promote the formation of 1T-MoS2. The intercalation agent sodium borohydride can provide Na ions to embed into the interlayers of MoS2 to obtain few-layer MoS2. Sodium borohydride is reducing and can help the production of 1T-MoS2.

[0015] In a preferred embodiment, in step S2, the oven heating temperature is 180-210° C., and the heating time is 16-24 hours.

[0016] In a preferred embodiment, in step S3, a centrifuge is used for centrifugation, the speed of the centrifuge is set to 8000 rpm / h, and the centrifugation time is set to 3 min.

[0017] In a preferred embodiment, in step S3, the number of centrifugation is 3-6 times.

[0018] In a preferred embodiment, in step S4, the freeze-drying time is set to 12-24 hours.

[0019] It should be noted that freeze-drying can be used to stabilize the structure of the few-layer 1T-MoS2.

[0020] The present invention also proposes the use of a few-layer 1T-MoS2 powder prepared by the method for preparing a few-layer metal phase molybdenum disulfide as described in any of the above items in electrochemical electrode materials.

[0021] Beneficial effects of the present invention:

[0022] 1. Compared with the existing preparation method, the preparation method of the present invention has simple equipment, cheaper raw materials, low energy consumption, simple process and wider applicability;

[0023] 2. The present invention provides a higher vapor pressure for the closed hydrothermal environment by adding an appropriate amount of alcohol, thereby obtaining 1T-MoS2 with higher purity;

[0024] 3. The present invention obtains a few-layer metal phase MoS2 by adding an intercalation agent, sodium borohydride, shortens the ion diffusion path, improves the conductivity of MoS2, increases its active sites, and makes it have more superior conductivity;

[0025] 4. The preparation method of the present invention can realize the large-scale preparation of few-layer 1T phase MoS2 materials, which is more conducive to scientific research promotion and industrialization compared with other methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 X-ray diffraction (XRD) pattern and Raman spectrum of the few-layer 1T-MoS2 prepared in Example 1 of the present invention;

[0027] Figure 2 An atomic force microscope (AFM) photograph of the few-layer 1T-MoS2 prepared in Example 1 of the present invention;

[0028] Figure 3 A transmission electron microscope (TEM) photograph of the few-layer 1T-MoS2 prepared in Example 1 of the present invention;

[0029] Figure 4 CV graph, GCD graph and EIS graph of the few-layer 1T-MoS2 prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0031] Example 1

[0032] Reference Figure 1-4 , a method for preparing a few-layer metallic phase molybdenum disulfide, comprising the following steps:

[0033] S1: Take 0.3685g of thioacetamide, 0.4113g of sodium molybdate dihydrate and 0.2596g of intercalation agent sodium borohydride, add them to a mixed solution of 12mL of deionized water and 6mL of alcohol, dissolve them in a 50mL polytetrafluoroethylene liner of a high-pressure reactor, then place it on a magnetic stirrer and stir for 15 minutes. After stirring, take out the magnetic bar, and then fill the liner into the steel jacket of the high-pressure reactor and seal it completely;

[0034] S2: placing the autoclave in a 200°C constant temperature drying oven for hydrothermal reaction for 20 hours to obtain a precursor solution;

[0035] S3: After the oven temperature drops to room temperature, take out the sample and transfer it into a centrifuge tube. Centrifuge it three times with water and twice with alcohol. The centrifuge speed is 8000 rpm / h for 3 minutes.

[0036] S4: After centrifugation, place the sample in a centrifuge tube with its mouth open and freeze it in a refrigerator. After freezing, place the sample in a freeze vacuum dryer for 24 hours to obtain a few-layer 1T-MoS2.

[0037] Example 2

[0038] A method for preparing a few-layer metal phase molybdenum disulfide comprises the following steps:

[0039] S1: Take 0.4185g of thioacetamide, 0.4513g of sodium molybdate dihydrate and 0.2796g of intercalation agent sodium borohydride, add them to a mixed solution of 12mL of deionized water and 4mL of alcohol, dissolve them in a 50mL polytetrafluoroethylene liner of a high-pressure reactor, then place it on a magnetic stirrer and stir for 15 minutes. After stirring, take out the magnetic bar, and then fill the liner into the steel jacket of the high-pressure reactor and seal it completely;

[0040] S2: placing the autoclave in a 220°C constant temperature drying oven for hydrothermal reaction for 18 hours to obtain a precursor solution;

[0041] S3: After the oven temperature drops to room temperature, take out the sample and transfer it into a centrifuge tube. Centrifuge it three times with water and twice with alcohol. The centrifuge speed is 8000 rpm / h for 3 minutes.

[0042] S4: After centrifugation, place the sample in a centrifuge tube with its mouth open and freeze it in a refrigerator. After freezing, place the sample in a freeze vacuum dryer for 24 hours to obtain a few-layer 1T-MoS2.

[0043] Example 3

[0044] A method for preparing a few-layer metal phase molybdenum disulfide comprises the following steps:

[0045] S1: Take 0.3285g of thioacetamide, 0.3713g of sodium molybdate dihydrate and 0.2396g of intercalation agent sodium borohydride, add them to a mixed solution of 12mL of deionized water and 3mL of alcohol, dissolve them in a 50mL polytetrafluoroethylene liner of a high-pressure reactor, then place it on a magnetic stirrer and stir for 15 minutes. After stirring, take out the magnetic bar, and then fill the liner into the steel jacket of the high-pressure reactor and seal it completely;

[0046] S2: placing the high-pressure reactor in a 180°C constant temperature drying oven for hydrothermal reaction for 24 hours to obtain a precursor solution;

[0047] S3: After the oven temperature drops to room temperature, take out the sample and transfer it into a centrifuge tube. Centrifuge it three times with water and twice with alcohol. The centrifuge speed is 8000 rpm / h for 3 minutes.

[0048] S4: After centrifugation, place the sample in a centrifuge tube with its mouth open and freeze it in a refrigerator. After freezing, place the sample in a freeze vacuum dryer for 24 hours to obtain a few-layer 1T-MoS2.

[0049] Example 4

[0050] A method for preparing a few-layer metal phase molybdenum disulfide comprises the following steps:

[0051] S1: Take 0.3685g of thioacetamide, 0.4113g of sodium molybdate dihydrate and 0.2596g of intercalation agent sodium borohydride, add them to a mixed solution of 12mL of deionized water and 2mL of alcohol, dissolve them in a 50mL polytetrafluoroethylene liner of a high-pressure reactor, then place it on a magnetic stirrer and stir for 15 minutes. After stirring, take out the magnetic bar, and then fill the liner into the steel jacket of the high-pressure reactor and seal it completely;

[0052] S2: placing the high-pressure reactor in a 220°C constant temperature drying oven for hydrothermal reaction for 20 hours to obtain a precursor solution;

[0053] S3: After the oven temperature drops to room temperature, take out the sample and transfer it into a centrifuge tube. Centrifuge it three times with water and twice with alcohol. The centrifuge speed is 8000 rpm / h for 3 minutes.

[0054] S4: After centrifugation, place the sample in a centrifuge tube with its mouth open and freeze it in a refrigerator. After freezing, place the sample in a freeze vacuum dryer for 24 hours to obtain a few-layer 1T-MoS2.

[0055] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the attached claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0056] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for preparing a few-layer metallic phase molybdenum disulfide, characterized in that: The following steps are involved: S1: Weigh a certain amount of thioacetamide, sodium molybdate dihydrate and intercalation agent sodium borohydride, add them to a mixed solution of deionized water and alcohol in different proportions, transfer them into a polytetrafluoroethylene liner, then place them on a magnetic stirrer and stir for a preset time. After removing the magnet, move the polytetrafluoroethylene liner into the steel jacket of the high-pressure reactor and seal it completely; S2: placing the high-pressure reactor in an oven for a preset time, and continuing the reaction for several hours to obtain a precursor solution; S3: taking out the precursor solution after hydrothermal treatment, centrifuging it with water and ethanol for several times, and taking out the lower precipitate; S4: Freeze-dry the lower precipitate for several hours, and the resulting sample is a few-layer 1T-MoS2 powder.

2. The method for preparing a few-layer metallic phase molybdenum disulfide according to claim 1, characterized in that: In step S1, the thioacetamide is 0.3-0.5 g, the sodium molybdate dihydrate is 0.3-0.5 g, the mass of the intercalation agent sodium borohydride is 0.2-0.4 g, the volume of deionized water added is 12 mL, and the volume of the alcohol solution is 2-8 mL.

3. The method for preparing a few-layer metallic phase molybdenum disulfide according to claim 1, characterized in that: In step S2, the oven heating temperature is 180-210°C and the heating time is 16-24h.

4. The method for preparing a few-layer metallic phase molybdenum disulfide according to claim 1, characterized in that: In step S3, a centrifuge is used for centrifugation, the rotation speed of the centrifuge is set to 8000 rpm / h, and the centrifugation time is set to 3 min.

5. The method for preparing a few-layer metallic phase molybdenum disulfide according to claim 1, characterized in that: In step S3, the number of centrifugation is 3-6 times.

6. The method for preparing a few-layer metallic phase molybdenum disulfide according to claim 1, characterized in that: In step S4, the freeze-drying time is set to 12-24 hours.

7. Use of the few-layer 1T-MoS2 powder obtained by the method for preparing a few-layer metallic phase molybdenum disulfide as described in any one of claims 1 to 6 in electrochemical electrode materials.

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