A 1T phase molybdenum disulfide and its preparation method and application

Abstract

The present invention belongs to the field of two-dimensional nanomaterial electrocatalysis, and relates to a 1T phase molybdenum disulfide and its preparation method and application. Ammonium molybdate tetrahydrate, thiourea and nickel nitrate are dissolved in water, and then heated to 170-190°C for hydrothermal reaction to obtain the molar amount of nickel nitrate, wherein the molar amount of nickel nitrate is 1-3% of the molar amount of ammonium molybdate tetrahydrate. The present invention prepares highly stable 1T phase molybdenum disulfide by a simple and easy hydrothermal method, and the prepared 1T phase molybdenum disulfide has better hydrogen evolution performance.

Description

Technical Field

[0001] The invention belongs to the field of two-dimensional nanomaterial electrocatalysis and relates to 1T phase molybdenum disulfide and a preparation method and application thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] Hydrogen evolution by electrolysis of water is one of the effective ways to solve the energy crisis and environmental pollution facing the world today. Transition metal dihalides (TMDs), especially molybdenum disulfide (MoS2), have attracted widespread attention due to their high activity, low cost and rich composition. Their common forms are semiconductor phase (1T) and metal phase (2H), of which 2H is more stable than 1T phase but has poor conductivity. According to the inventor's research, although 1T phase MoS2 has high activity and good conductivity, it is difficult to prepare and has poor stability. Summary of the invention

[0004] In order to overcome the deficiencies in the prior art, the purpose of the present invention is to provide a 1T phase molybdenum disulfide and a preparation method and application thereof. The present invention prepares a highly stable 1T phase molybdenum disulfide by a simple and easy hydrothermal method, and the prepared 1T phase molybdenum disulfide has better hydrogen evolution performance (HER).

[0005] In order to achieve the above object, the technical solution of the present invention is:

[0006] On the one hand, a method for preparing 1T phase molybdenum disulfide is provided, wherein ammonium molybdate tetrahydrate, thiourea and nickel nitrate are dissolved in water, and then heated to 170-190°C for hydrothermal reaction to obtain the obtained product; wherein the molar amount of nickel nitrate is 1-3% of the molar amount of ammonium molybdate tetrahydrate.

[0007] The present invention has shown that molybdenum disulfide can be obtained by hydrothermal reaction with ammonium molybdate tetrahydrate as a molybdenum source and thiourea as a sulfur source, but the obtained molybdenum disulfide is a 2H phase, and the hydrogen evolution experiment shows that the hydrogen evolution performance of the 2H phase molybdenum disulfide obtained by this method is poor. Based on this, the present invention adds a small amount of nickel nitrate at the beginning of the reaction, with the purpose of nickel doping the molybdenum disulfide. After adding a small amount of nickel nitrate for hydrothermal reaction, it is unexpectedly found that for the hydrothermal reaction system based on ammonium molybdate tetrahydrate as a molybdenum source and thiourea as a sulfur source of the present invention, adding a small amount of nickel nitrate for doping is beneficial to the phase change of molybdenum disulfide to generate 1T phase molybdenum disulfide.

[0008] On the other hand, a 1T phase molybdenum disulfide is obtained by the above preparation method.

[0009] In the third aspect, an application of the above-mentioned 1T phase molybdenum disulfide in catalytic water electrolysis to produce hydrogen.

[0010] The beneficial effects of the present invention are:

[0011] The present invention can prepare 1T phase molybdenum disulfide with high stability by adding a small amount of nickel nitrate to a hydrothermal reaction system for preparing molybdenum disulfide using ammonium molybdate tetrahydrate as a molybdenum source and thiourea as a sulfur source. Hydrogen evolution experiments show that the 1T phase molybdenum disulfide prepared by the present invention can significantly improve hydrogen evolution performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0013] Figure 1 XRD patterns of molybdenum disulfide prepared in the examples and comparative examples of the present invention;

[0014] Figure 2 The Raman spectra of molybdenum disulfide prepared in the examples and comparative examples of the present invention;

[0015] Figure 3 The figure is a result diagram of the hydrogen evolution performance of molybdenum disulfide prepared in the examples and comparative examples of the present invention. DETAILED DESCRIPTION

[0016] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0017] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0018] In view of the problems that 1T phase molybdenum disulfide is difficult to prepare and has poor stability, the present invention proposes a 1T phase molybdenum disulfide and a preparation method and application thereof.

[0019] A typical embodiment of the present invention provides a method for preparing 1T phase molybdenum disulfide, wherein ammonium molybdate tetrahydrate, thiourea and nickel nitrate are dissolved in water, and then heated to 170-190°C for hydrothermal reaction to obtain the molar amount of nickel nitrate, wherein the molar amount of nickel nitrate is 1-3% of the molar amount of ammonium molybdate tetrahydrate.

[0020] Studies have shown that the method of the present invention can produce 1T phase molybdenum disulfide with high stability.

[0021] The hydrothermal reaction described in the present invention refers to a reaction in which the pressure in the closed system generated by heating is higher than the pressure of the external environment under closed conditions with water as the solvent.

[0022] In some embodiments, the method of adding ammonium molybdate tetrahydrate, thiourea and nickel nitrate into water for dissolution is: first ultrasonication and then stirring. This method has a better dissolution effect.

[0023] In one or more embodiments, the ultrasonic time is 5 to 15 minutes, and the stirring time is 1.5 to 2.5 hours.

[0024] In some embodiments, the molar ratio of ammonium molybdate tetrahydrate to thiourea is 1:25-30.

[0025] In some embodiments, in the hydrothermal reaction system, the ratio of the volume of water to the volume of the high-pressure reactor is 0.7 to 0.9:1.

[0026] In some embodiments, the hydrothermal reaction time is 22 to 26 hours.

[0027] In some embodiments, during the hydrothermal reaction, carbon cloth is added into the autoclave to provide a growth site for molybdenum disulfide.

[0028] In some embodiments, after the hydrothermal reaction, the reaction ethanol and water are rinsed and then dried.

[0029] Another embodiment of the present invention provides a 1T phase molybdenum disulfide obtained by the above preparation method.

[0030] A third embodiment of the present invention provides an application of the above-mentioned 1T phase molybdenum disulfide in catalytic water electrolysis to produce hydrogen.

[0031] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in combination with specific embodiments and comparative examples.

[0032] Comparative Example

[0033] (1) 1mmol(NH4)6Mo7O 24 4H2O and 28mmol CS(NH2)2 were dissolved in 40mL deionized water and ultrasonicated for 10min and then stirred for 2h.

[0034] (2) The completely dissolved mixture was transferred into a 50 mL polytetrafluoroethylene-lined stainless steel autoclave, the carbon cloth (CC) was placed vertically into the solution, and then heated at 180 °C for 24 h.

[0035] (3) After cooling, the sample was repeatedly rinsed with ethanol and distilled water to remove impurities, and then dried at 60 °C to obtain a MoS2 sample.

[0036] Example 1

[0037] (1) 1mmol(NH4)6Mo7O 24 ·4H2O, 28mmol CS(NH2)2 and 0.02mmol Ni(NO3)2·6H2O were dissolved in 40mL deionized water and ultrasonically treated for 10min and then stirred for 2h.

[0038] (2) The completely dissolved mixture was transferred into a 50 mL polytetrafluoroethylene-lined stainless steel autoclave, the carbon cloth (CC) was placed vertically into the solution, and then heated at 180 °C for 24 h.

[0039] (3) After cooling, the sample was repeatedly rinsed with ethanol and distilled water to remove impurities, and then dried at 60 °C to obtain a Ni-doped 1T-MoS2 sample, which was denoted as MoS2-Ni.

[0040] The XRD and Raman spectra of MoS2-Ni obtained in this example and MoS2 prepared in the comparative example are as follows: Figures 1-2 shown. Figure 1 In the figure, the (001) diffraction peak is the characteristic peak of the 1T phase of MoS2. The MoS2-Ni prepared in Example 1 shows an obvious (001) diffraction peak, indicating that the MoS2 in the MoS2-Ni prepared in Example 1 is a 1T phase. Figure 2 In the figure, J1, J2, and J3 are characteristic peaks of the 1T phase. The MoS2-Ni prepared in Example 1 simultaneously exhibits the characteristic peaks of J1, J2, and J3, which further indicates that the MoS2 in the MoS2-Ni prepared in Example 1 is a 1T phase.

[0041] Hydrogen evolution performance experiment:

[0042] On an electrochemical analyzer, the prepared sample was used as the working electrode, the Pt sheet was used as the counter electrode, and the Hg / HgO was used as the reference electrode in a three-electrode system. In a 1M KOH solution at room temperature, the iR-corrected linear sweep voltammetry (LSV) measurement of MoS2 and Ni-MoS2 was performed at a scan rate of 5 mV / s. All the measured potentials were RHE calibrated by the Nernst equation.

[0043] The results are as follows Figure 3 As shown, at 10mA / cm 2At a current density of , the hydrogen evolution overpotential is reduced from 216 mV to 106 mV, and the hydrogen evolution performance is significantly improved.

[0044] In general, the results show that the MoS2-Ni prepared in Example 1 significantly improves the hydrogen evolution performance.

[0045] Example 2

[0046] (1) 1mmol(NH4)6Mo7O 24 ·4H2O, 25mmol CS(NH2)2 and 0.02mmol Ni(NO3)2·6H2O were dissolved in 40mL of deionized water and ultrasonicated for 10min and then stirred for 2h.

[0047] (2) The completely dissolved mixture was transferred into a 50 mL polytetrafluoroethylene-lined stainless steel autoclave, the carbon cloth (CC) was placed vertically into the solution, and then heated at 180 °C for 24 h.

[0048] (3) After cooling, the sample was repeatedly rinsed with ethanol and distilled water to remove impurities, and then dried at 60 °C to obtain a Ni-doped 1T-MoS2 sample, which was denoted as MoS2-Ni.

[0049] Example 3

[0050] (1) 1mmol(NH4)6Mo7O 24 ·4H2O, 30mmol CS(NH2)2 and 0.02mmol Ni(NO3)2·6H2O were dissolved in 40mL deionized water and ultrasonically treated for 10min and then stirred for 2h.

[0051] (2) The completely dissolved mixture was transferred into a 50 mL polytetrafluoroethylene-lined stainless steel autoclave, the carbon cloth (CC) was placed vertically into the solution, and then heated at 180 °C for 24 h.

[0052] (3) After cooling, the sample was repeatedly rinsed with ethanol and distilled water to remove impurities, and then dried at 60 °C to obtain a Ni-doped 1T-MoS2 sample, which was denoted as MoS2-Ni.

[0053] Example 4

[0054] (1) 1mmol(NH4)6Mo7O 24 ·4H2O, 28mmol CS(NH2)2 and 0.01mmol Ni(NO3)2·6H2O were dissolved in 40mL deionized water and ultrasonically treated for 10min and then stirred for 2h.

[0055] (2) The completely dissolved mixture was transferred into a 50 mL polytetrafluoroethylene-lined stainless steel autoclave, the carbon cloth (CC) was placed vertically into the solution, and then heated at 180 °C for 24 h.

[0056] (3) After cooling, the sample was repeatedly rinsed with ethanol and distilled water to remove impurities, and then dried at 60 °C to obtain a Ni-doped 1T-MoS2 sample, which was denoted as MoS2-Ni.

[0057] Example 5

[0058] (1) 1mmol(NH4)6Mo7O 24 ·4H2O, 28mmol CS(NH2)2 and 0.03mmol Ni(NO3)2·6H2O were dissolved in 40mL deionized water and ultrasonically treated for 10min and then stirred for 2h.

[0059] (2) The completely dissolved mixture was transferred into a 50 mL polytetrafluoroethylene-lined stainless steel autoclave, the carbon cloth (CC) was placed vertically into the solution, and then heated at 180 °C for 24 h.

[0060] (3) After cooling, the sample was repeatedly rinsed with ethanol and distilled water to remove impurities, and then dried at 60 °C to obtain a Ni-doped 1T-MoS2 sample, which was denoted as MoS2-Ni.

[0061] Example 6

[0062] (1) 1mmol(NH4)6Mo7O 24 ·4H2O, 28mmol CS(NH2)2 and 0.02mmol Ni(NO3)2·6H2O were dissolved in 40mL deionized water and ultrasonically treated for 10min and then stirred for 2h.

[0063] (2) The completely dissolved mixture was transferred into a 50 mL polytetrafluoroethylene-lined stainless steel autoclave, the carbon cloth (CC) was placed vertically into the solution, and then heated at 170 °C for 24 h.

[0064] (3) After cooling, the sample was repeatedly rinsed with ethanol and distilled water to remove impurities, and then dried at 60 °C to obtain a Ni-doped 1T-MoS2 sample, which was denoted as MoS2-Ni.

[0065] Example 7

[0066] (1) 1mmol(NH4)6Mo7O 24 ·4H2O, 28mmol CS(NH2)2 and 0.02mmol Ni(NO3)2·6H2O were dissolved in 40mL deionized water and ultrasonically treated for 10min and then stirred for 2h.

[0067] (2) The completely dissolved mixture was transferred into a 50 mL polytetrafluoroethylene-lined stainless steel autoclave, the carbon cloth (CC) was placed vertically into the solution, and then heated at 190 °C for 24 h.

[0068] (3) After cooling, the sample was repeatedly rinsed with ethanol and distilled water to remove impurities, and then dried at 60 °C to obtain a Ni-doped 1T-MoS2 sample, which was denoted as MoS2-Ni.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An application of 1T phase molybdenum disulfide in catalytic water electrolysis to produce hydrogen, characterized in that: At 10mA / cm 2 At a current density of , the hydrogen evolution overpotential is 106mV; The preparation method of the 1T phase molybdenum disulfide is as follows: Dissolve ammonium molybdate tetrahydrate, thiourea and nickel nitrate in water, and then heat to 170-190° C. for hydrothermal reaction to obtain the product; wherein the molar amount of the nickel nitrate is 1-3% of the molar amount of the ammonium molybdate tetrahydrate; The molar ratio of ammonium molybdate tetrahydrate to thiourea is 1:25-30; and the hydrothermal reaction time is 22-26 hours.

2. The use according to claim 1, characterized in that: The method of adding ammonium molybdate tetrahydrate, thiourea and nickel nitrate into water for dissolution is: firstly ultrasonicating and then stirring.

3. The use according to claim 2, characterized in that: The ultrasonic time is 5 to 15 minutes, and the stirring time is 1.5 to 2.5 hours.

4. The use according to claim 1, characterized in that: In the hydrothermal reaction system, the ratio of the volume of water to the volume of the high-pressure reactor is 0.7-0.9:

1.

5. The use according to claim 1, characterized in that: During the hydrothermal reaction, carbon cloth is added into the high-pressure reactor.

6. The use according to claim 2, characterized in that: After the hydrothermal reaction, the reaction ethanol and water are used for washing and then drying is performed.

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