A nickel-molybdenum-based hydrogen evolution material and a one-step hydrothermal synthesis method and application thereof

Abstract

The present invention belongs to the technical field of hydrogen evolution materials, and particularly relates to a highly efficient and stable nickel-molybdenum-based hydrogen evolution material, and discloses a method for synthesizing the nickel-molybdenum-based hydrogen evolution material based on a one-step hydrothermal method and its application. The nickel-molybdenum-based hydrogen evolution material of the present invention uses (NH4)2MoS4 as the Mo source and S source, and nickel salt as the nickel source to prepare a MoS2 / Ni3S2 composite material. The nickel-molybdenum-based hydrogen evolution material of the present invention exhibits excellent hydrogen evolution performance and stability.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrogen evolution materials, and specifically relates to a highly efficient and stable nickel-molybdenum-based hydrogen evolution material, and discloses a method for synthesizing the nickel-molybdenum-based hydrogen evolution material based on a one-step hydrothermal method. Background Art

[0002] The increasingly serious energy crisis and environmental pollution urgently require the development of green, efficient and renewable energy. Hydrogen energy is recognized as the most ideal energy carrier for the future of mankind because of its clean, carbon-free, easy to transmit, high energy density, sustainability, carbon-free and renewable characteristics. At present, the commonly used hydrogen production methods in industry include methane reforming, coal gasification and water electrolysis. Among them, although methane reforming and coal gasification methods are relatively mature, they will emit a large amount of carbon dioxide, which runs counter to the concept of "dual carbon". In contrast, water electrolysis hydrogen production technology is an efficient, clean and pollution-free method that can not only meet the large-scale hydrogen market demand, but also couple clean energy such as solar energy and wind energy.

[0003] However, currently only 4% of the world's hydrogen comes from water electrolysis technology. The main reason is that the overpotential of the catalyst is high, resulting in huge energy consumption, which has become an important limiting factor for the development of this technology. In addition, the anion exchange membrane water electrolyzer (Anion Exchange Membrane Water Electrolyzer) that has emerged in recent years requires a hydrogen evolution catalyst with high activity and strong mechanical and chemical stability due to the higher local hydroxide concentration in the membrane electrode and extremely high mass transfer performance requirements in the membrane electrode. Therefore, the field expects to develop a hydrogen evolution catalyst that is easy to prepare, has high catalytic activity and long life, which is of great significance to reducing the cost of water electrolysis hydrogen production equipment.

[0004] Alkaline water electrolysis is the most mature water electrolysis technology in the industry due to its low operating temperature, low cost and high stability. However, under strong alkaline conditions, the overpotential of the hydrogen evolution reaction is higher and the stability is poor. Therefore, in the past few decades, researchers from all over the world have been developing cheap, easily available, efficient and stable hydrogen evolution catalysts. As a classic porous hydrogen evolution catalyst, Raney nickel has been used since it was discovered in the 1920s. However, its preparation process requires repeated calcination, resulting in high energy consumption.

[0005] In recent years, transition metal sulfides have been widely used in the field of electrocatalysis due to their high chemical stability and catalytic activity. Molybdenum disulfide (MoS2) is a typical transition metal sulfide with good hydrogen evolution effect and strong chemical stability. However, due to the inertness and semiconductor properties of its basal plane, only the S sites at the edge have HER activity. At present, this field mainly improves its activity by dispersing the active sites of MoS2 on a porous substrate by loading, ultrasonic dispersion, and creating vacancies (Adv. Mater. 2017, 29, 1703863; Adv. Funct. Mater. 2022, 2208994). In addition, there are a large number of Ni-S and Ni-Ni bonds in Ni3S2, so the generation of intermediates such as -OOH and -H can be accelerated. Zou Xiaoxin's group, Wu Zhengcui's group, and others found that Ni3S2 exhibited good catalytic activity for complete hydrolysis under strong alkaline conditions (CN 202210438639.2; J.Am.Chem.Soc.2015,137,14023;

[0006] ChemElectroChem 2019,6,4550). However, due to the strong adsorption of Ni3S2 and OH, its hydrogen evolution overpotential is relatively high. In recent years, researchers have begun to prepare MoS2 / Ni3S2 composite materials (Chem.Eng.J.2022,428,131055; J.Alloys Compd.2018,737,809; Nano Energy 2016,20,1; CN 202210091676.0; CN202111476735.8), and applied them to the fields of full hydrolysis, supercapacitors, batteries, etc., and achieved good results. However, the above-mentioned catalyst materials have problems such as complicated preparation process or low catalytic activity due to the small specific surface area of ​​the catalyst, and their performance cannot meet practical applications. Summary of the invention

[0007] To this end, the technical problem to be solved by the present invention is to provide an efficient and stable nickel-molybdenum-based hydrogen evolution material, which has a high specific surface area, exhibits excellent hydrogen evolution catalytic performance under strong alkaline, weak alkaline and neutral conditions, can be used as a cathode in neutral, weak alkaline, especially strong alkaline water electrolyzers, and has the advantages of low overpotential and long durability;

[0008] The second technical problem to be solved by the present invention is to provide a method for preparing the nickel-molybdenum-based hydrogen evolution material based on a one-step hydrothermal synthesis method.

[0009] In order to solve the above technical problems, the present invention discloses a method for preparing nickel-molybdenum-based hydrogen evolution material by one-step hydrothermal synthesis, comprising the step of using (NH4)2MoS4 as Mo source and S source and nickel salt as nickel source to prepare MoS2 / Ni3S2 grain boundary by one-step hydrothermal method.

[0010] Specifically, the method for preparing nickel-molybdenum-based hydrogen evolution material by one-step hydrothermal synthesis comprises the following steps:

[0011] (1) preparing (NH4)2MoS4 solution and nickel salt solution respectively and mixing them to obtain a suspension;

[0012] (2) A nickel substrate is added to the suspension to carry out a hydrothermal synthesis reaction, thereby obtaining the desired nickel-molybdenum-based hydrogen evolution material.

[0013] Specifically, in the method for preparing nickel-molybdenum-based hydrogen evolution material by one-step hydrothermal synthesis, in step (1), the concentration of the (NH4)2MoS4 solution is 10-30 mmol / L;

[0014] Preferably, the solvent for preparing the (NH4)2MoS4 solution includes water.

[0015] Specifically, in the one-step hydrothermal synthesis method for preparing nickel-molybdenum-based hydrogen evolution material, in the step (1), the concentration of the nickel salt solution is 3-8 mmol / L;

[0016] Preferably, the nickel salt used to prepare the nickel salt solution includes at least one of NiCl2·6H2O, Ni(NO3)2·6H2O, NiSO4·6H2O or Ni(OAc)2·6H2O;

[0017] Preferably, the solvent for preparing the nickel salt solution includes at least one of water, N,N-dimethylformamide (DMF), ethylene glycol, isopropanol or N-methylpyrrolidone (NMP).

[0018] Specifically, in the method for preparing nickel-molybdenum-based hydrogen evolution material by one-step hydrothermal synthesis, in step (1), the volume ratio of the (NH4)2MoS4 solution to the nickel salt solution is 3-8:1.

[0019] Specifically, in the method for preparing nickel-molybdenum-based hydrogen evolution material by one-step hydrothermal synthesis, in step (1), the mixing step includes the step of dropwise adding the nickel salt solution to the (NH4)2MoS4 solution;

[0020] Preferably, the dropping time is controlled to be 20-40 min, and more preferably, the dropping process is controlled to be dropping at a uniform speed.

[0021] Specifically, in the method for preparing nickel-molybdenum-based hydrogen evolution material by one-step hydrothermal synthesis, in step (2), the hydrothermal synthesis reaction step is a closed reaction, the reaction temperature is controlled to be 160-200° C., and the reaction time is 8-24 hours.

[0022] Specifically, in the method for preparing nickel-molybdenum-based hydrogen evolution material by one-step hydrothermal synthesis, in step (2), the nickel substrate comprises foamed nickel;

[0023] Preferably, the step (2) further comprises the step of cleaning the nickel substrate; specifically, the cleaning step comprises ultrasonically cleaning the nickel foam or nickel mesh substrate using dilute hydrochloric acid, water, and ethanol in sequence to remove the oxide layer and oil stains on the surface of the substrate;

[0024] Preferably, the step (2) further comprises the step of cleaning and / or drying the nickel-molybdenum-based hydrogen evolution material; specifically, the cleaning step comprises the step of cleaning with water and ethanol and then vacuum drying.

[0025] The invention also discloses a nickel-molybdenum-based hydrogen evolution material prepared by the method.

[0026] The invention also discloses the use of the nickel-molybdenum-based hydrogen evolution material in preparing a hydrogen evolution catalyst and a hydrogen evolution electrode.

[0027] The invention also discloses a hydrogen evolution catalyst, a hydrogen evolution electrode, an electrolytic hydrogen evolution device or an electrolytic hydrogen evolution system prepared from the nickel-molybdenum-based hydrogen evolution material.

[0028] The invention also discloses an electrolytic hydrogen evolution process, comprising the step of using the nickel-molybdenum-based hydrogen evolution material as a catalyst to perform hydrogen evolution electrolysis.

[0029] The nickel-molybdenum-based hydrogen evolution material of the present invention uses (NH4)2MoS4 as the Mo source and S source and nickel salt as the nickel source to prepare a MoS2 / Ni3S2 composite material. The nickel-molybdenum-based hydrogen evolution material not only has a large specific surface area, which is beneficial to mass transfer and gas departure; but also has a MoS2 / Ni3S2 phase boundary structure, which is beneficial to expose more catalytic active sites; at the same time, the amorphous MoO x The introduction of the amorphous phase can also adjust the ability of the catalyst to bind water, that is, it can effectively regulate the adsorption of water and the desorption of hydroxide in the catalytic process, which is beneficial to improve the reaction kinetics and thereby improve its hydrogen production activity; in the hydrogen evolution material, there is an electronic and synergistic effect between the two phases, which effectively improves the hydrogen evolution performance of the material. The nickel-molybdenum-based hydrogen evolution material of the present invention exhibits excellent hydrogen evolution performance and stability.

[0030] The nickel-molybdenum-based hydrogen evolution material of the present invention is prepared by a one-step hydrothermal synthesis method to form a MoS2 / Ni3S2 grain boundary, and amorphous MoO xThe method can grow and synthesize the desired hydrogen evolution material on a nickel substrate in one step. The hydrogen evolution material of the present invention has a large specific surface area and is used as a catalyst. It has excellent hydrogen evolution catalytic activity under neutral, weakly alkaline and strongly alkaline conditions and has a wide range of applications. The hydrogen evolution catalyst does not need to be loaded on an electrode and can be directly used as an electrode for electrocatalytic hydrogen production, which is more convenient and efficient.

[0031] The nickel-molybdenum-based hydrogen evolution material of the present invention is suitable for different nickel substrates such as nickel foam and nickel mesh, and has the advantages of being simple, safe to operate and low cost. The preparation process of the present invention is simple, and the bonding ability between the catalyst and the substrate is strong, so it is suitable for serving as a cathode material in an industrial water electrolysis device. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein:

[0033] Figure 1 This is a scanning electron microscope image of the hydrogen evolution material prepared in Example 1 (Example 1-180°C);

[0034] Figure 2 XRD pattern of the hydrogen evolution material prepared in Example 1 (Example 1-180°C);

[0035] Figure 3 HRTEM image of the hydrogen evolution material prepared in Example 1 (Example 1-180°C);

[0036] Figure 4 This is a scanning electron microscope image of the hydrogen evolution material prepared in Example 5;

[0037] Figure 5 Scanning electron microscope image of hydrogen evolution material prepared in Example 6;

[0038] Figure 6 Scanning electron microscope image of hydrogen evolution material prepared in Example 7;

[0039] Figure 7 The results of the hydrogen evolution catalytic performance of the samples synthesized at different hydrothermal temperatures in Example 1 in 1M KOH;

[0040] Figure 8 The hydrogen evolution catalytic performance results of the hydrogen evolution materials prepared in Examples 1-4 in 1M KOH;

[0041] Fig. 9 The hydrogen evolution catalytic performance results of the hydrogen evolution materials prepared in Examples 5-8 in 1M KOH;

[0042] Fig.10The results of the hydrogen evolution catalytic performance of the hydrogen evolution material prepared in Example 1 in 1M phosphate buffer solution (PBS, pH=7.0);

[0043] Fig.11 The hydrogen evolution catalytic performance results of the hydrogen evolution material prepared in Example 1 in 1M PBS (pH=9.0);

[0044] Fig.12 1A cm-1 of the hydrogen evolution material prepared in Example 1 in 1M KOH -2 The hydrogen evolution stability results at

[0045] Fig.13 The hydrogen evolution material prepared in Example 1 was 1A cm in 1M PBS (pH=7.0) -2 The hydrogen evolution stability results at

[0046] Fig.14 The hydrogen evolution material prepared in Example 1 was 1A cm in 1M PBS (pH=9.0) -2 The hydrogen evolution stability results at

[0047] Fig.15 The catalytic performance results of hydrogen evolution in 1M KOH of the hydrogen evolution material prepared in Example 1 and the comparative sample;

[0048] Fig.16 The relationship between the capacitive current and the scan rate of the hydrogen evolution material and the comparative sample prepared in Example 1;

[0049] Fig.17 Sample pictures of hydrogen evolution materials prepared in the examples (Example 1-180°C) on nickel foam and nickel mesh. DETAILED DESCRIPTION

[0050] The present invention is further described below in conjunction with specific embodiments. Referring to the following specific examples, those skilled in the art can adjust the raw materials, process parameters, etc. according to the scope of the present invention to prepare a variety of catalysts.

[0051] Example 1

[0052] The nickel foam (surface density 1500g / m 2 , thickness 1 cm) were cleaned with diluted hydrochloric acid, water, and ethanol ultrasonically in turn to remove the oxide layer and oil stains on the surface of the substrate.

[0053] A 20 mmol / L aqueous solution of (NH4)2MoS4 (denoted as solution A) and a 6 mmol / L aqueous solution of NiCl2·6H2O (denoted as solution B) were prepared respectively.

[0054] The prepared B solution was added dropwise to the A solution at a uniform rate, and the stirring was continued for 30 min to obtain a C suspension.

[0055] The obtained C suspension was transferred to a closed container, and the pretreated nickel foam substrate was added to perform a hydrothermal synthesis reaction, and the reaction temperature was controlled to be 160, 170, 180, 190, and 200°C, respectively, and the reaction time was 8 hours. After the reaction was completed, the reaction product was taken out, washed with water and ethanol, and then vacuum dried to obtain the desired nickel-molybdenum-based hydrogen evolution material, which was recorded as Example 1-160°C, Example 1-170°C, Example 1-180°C, Example 1-190°C, and Example 1-200°C, respectively.

[0056] The scanning electron microscope image of the nickel-molybdenum-based hydrogen evolution material (Example 1-180° C.) prepared in this embodiment is shown in the attached Figure 1 The XRD pattern of the hydrogen evolution material is shown in the attached Figure 2 The HRTEM image of the hydrogen evolution material is shown in the attached Figure 3 .

[0057] Depend on Figure 1 It can be seen that the method of the present invention can prepare nanorod materials composed of multi-level nanosheets, which is beneficial to catalytic kinetics; Figure 2 This proves that both MoS2 (PDF#37-1492) and Ni3S2 (PDF#44-1418) exist in the material; Figure 3 The HRTEM images show that there are a large number of MoS2 and Ni3S2 grain boundaries on the surface of the material, and there is MoO x Amorphous phase.

[0058] Example 2

[0059] The nickel foam (surface density 1500g / m 2 , thickness 1 cm) were cleaned with diluted hydrochloric acid, water, and ethanol ultrasonically in turn to remove the oxide layer and oil stains on the surface of the substrate.

[0060] A 20 mmol / L aqueous solution of (NH4)2MoS4 (denoted as solution A) and a 6 mmol / L aqueous solution of Ni(NO3)2·6H2O (denoted as solution B) were prepared respectively.

[0061] The prepared B solution was added dropwise to the A solution at a uniform rate, and the stirring was continued for 30 min to obtain a C suspension.

[0062] The obtained C suspension was transferred to a closed container, and the pretreated nickel foam substrate was added to perform a hydrothermal synthesis reaction, the temperature was controlled at 180°C, and the reaction time was 8 hours. After the reaction was completed, the reaction product was taken out, washed with water and ethanol, and then vacuum dried to obtain the desired nickel-molybdenum-based hydrogen evolution material.

[0063] Example 3

[0064] The nickel foam (surface density 1500g / m 2 , thickness 1 cm) were cleaned with diluted hydrochloric acid, water, and ethanol ultrasonically in turn to remove the oxide layer and oil stains on the surface of the substrate.

[0065] A 20 mmol / L aqueous solution of (NH4)2MoS4 (denoted as solution A) and a 6 mmol / L aqueous solution of NiSO4·6H2O (denoted as solution B) were prepared respectively.

[0066] The prepared B solution was added dropwise to the A solution at a uniform rate, and the stirring was continued for 30 min to obtain a C suspension.

[0067] The obtained C suspension was transferred to a closed container, and the pretreated nickel foam substrate was added to perform a hydrothermal synthesis reaction, the temperature was controlled at 180°C, and the reaction time was 8 hours. After the reaction was completed, the reaction product was taken out, washed with water and ethanol, and then vacuum dried to obtain the desired nickel-molybdenum-based hydrogen evolution material.

[0068] Example 4

[0069] The nickel foam (surface density 1500g / m 2 , thickness 1 cm) were cleaned with diluted hydrochloric acid, water, and ethanol ultrasonically in turn to remove the oxide layer and oil stains on the surface of the substrate.

[0070] A 20 mmol / L aqueous solution of (NH4)2MoS4 (denoted as solution A) and a 6 mmol / L aqueous solution of Ni(OAc)2·6H2O (denoted as solution B) were prepared respectively.

[0071] The prepared B solution was added dropwise to the A solution at a uniform rate, and the stirring was continued for 30 min to obtain a C suspension.

[0072] The obtained C suspension was transferred to a closed container, and the pretreated nickel foam substrate was added to perform a hydrothermal synthesis reaction, the temperature was controlled at 180°C, and the reaction time was 8 hours. After the reaction was completed, the reaction product was taken out, washed with water and ethanol, and then vacuum dried to obtain the desired nickel-molybdenum-based hydrogen evolution material.

[0073] Example 5

[0074] The nickel foam (surface density 1500g / m 2 , thickness 1 cm) were cleaned with diluted hydrochloric acid, water, and ethanol ultrasonically in turn to remove the oxide layer and oil stains on the surface of the substrate.

[0075] A 20 mmol / L (NH4)2MoS4 aqueous solution (denoted as solution A) and a 6 mmol / L NiCl2·6H2O isopropanol solution (denoted as solution B) were prepared respectively.

[0076] The prepared B solution was added dropwise to the A solution at a uniform rate, and the stirring was continued for 30 min to obtain a C suspension.

[0077] The obtained C suspension was transferred to a closed container, and the pretreated nickel foam substrate was added to perform a hydrothermal synthesis reaction, the temperature was controlled at 180°C, and the reaction time was 8 hours. After the reaction was completed, the reaction product was taken out, washed with water and ethanol, and then vacuum dried to obtain the desired nickel-molybdenum-based hydrogen evolution material.

[0078] The scanning electron microscope picture of the nickel-molybdenum-based hydrogen evolution material prepared in this embodiment is shown in the attached Figure 4 From the attached Figure 4 It can be seen from the results that the method of the present invention can obtain a smooth nanorod-like structure.

[0079] Example 6

[0080] The nickel foam (surface density 1500g / m 2 , thickness 1 cm) were cleaned with diluted hydrochloric acid, water, and ethanol ultrasonically in turn to remove the oxide layer and oil stains on the surface of the substrate.

[0081] A 20 mmol / L (NH4)2MoS4 aqueous solution (denoted as solution A) and a 6 mmol / L NiCl2·6H2O NMP (N-methylpyrrolidone) solution (denoted as solution B) were prepared respectively.

[0082] The prepared B solution was added dropwise to the A solution at a uniform rate, and the stirring was continued for 30 min to obtain a C suspension.

[0083] The obtained C suspension was transferred to a closed container, and the pretreated nickel foam substrate was added to perform a hydrothermal synthesis reaction, the temperature was controlled at 180°C, and the reaction time was 8 hours. After the reaction was completed, the reaction product was taken out, washed with water and ethanol, and then vacuum dried to obtain the desired nickel-molybdenum-based hydrogen evolution material.

[0084] The scanning electron microscope picture of the nickel-molybdenum-based hydrogen evolution material prepared in this embodiment is shown in the attached Figure 5 From the attached Figure 5 It can be seen from the results that the method of the present invention can obtain an irregular porous nanomaterial.

[0085] Example 7

[0086] The nickel foam (surface density 1500g / m 2 , thickness 1 cm) were cleaned with diluted hydrochloric acid, water, and ethanol ultrasonically in turn to remove the oxide layer and oil stains on the surface of the substrate.

[0087] A 20 mmol / L (NH4)2MoS4 aqueous solution (denoted as solution A) and a 6 mmol / L NiCl2·6H2O ethylene glycol solution (denoted as solution B) were prepared respectively.

[0088] The prepared B solution was added dropwise to the A solution at a uniform rate, and the stirring was continued for 30 min to obtain a C suspension.

[0089] The obtained C suspension was transferred to a closed container, and the pretreated nickel foam substrate was added to perform a hydrothermal synthesis reaction, the temperature was controlled at 180°C, and the reaction time was 8 hours. After the reaction was completed, the reaction product was taken out, washed with water and ethanol, and then vacuum dried to obtain the desired nickel-molybdenum-based hydrogen evolution material.

[0090] The scanning electron microscope picture of the nickel-molybdenum-based hydrogen evolution material prepared in this embodiment is shown in the attached Figure 6 From the attached Figure 6 It can be seen from the results that the method of the present invention can obtain a class of hierarchical porous nanomaterials.

[0091] Example 8

[0092] The nickel foam (surface density 1500g / m 2 , thickness 1 cm) were cleaned with diluted hydrochloric acid, water, and ethanol ultrasonically in turn to remove the oxide layer and oil stains on the surface of the substrate.

[0093] A 20 mmol / L (NH4)2MoS4 aqueous solution (denoted as solution A) and a 6 mmol / L NiCl2·6H2O DMF (N,N-dimethylformamide) solution (denoted as solution B) were prepared respectively.

[0094] The prepared B solution was added dropwise to the A solution at a uniform rate, and the stirring was continued for 30 min to obtain a C suspension.

[0095] The obtained C suspension was transferred to a closed container, and the pretreated nickel foam substrate was added to perform a hydrothermal synthesis reaction, the temperature was controlled at 180°C, and the reaction time was 8 hours. After the reaction was completed, the reaction product was taken out, washed with water and ethanol, and then vacuum dried to obtain the desired nickel-molybdenum-based hydrogen evolution material.

[0096] Comparative Example 1

[0097] The preparation method of the hydrogen evolution material in this comparative example is the same as that in Example 1, the only difference is that the Mo source material is (NH4)2MoO4, and the S source material is CS(NH2)2. The hydrothermal reaction temperature is 160°C, and the reaction time is 8h.

[0098] Comparative Example 2

[0099] 40% Pt / C powder (Johnson Matthey) and an appropriate amount of anionic adhesive were dispersed in a mixture of 1 mL of water and isopropanol and ultrasonically dispersed for 2 h until a uniform slurry was formed. Then, the obtained slurry was evenly sprayed on a nickel foam substrate (surface density 1500 g / m 2 , thickness 1cm, loading 1mg / cm 2 ), dried under vacuum at room temperature, and the obtained electrode was labeled as 40% Pt / C / NF.

[0100] Comparative Example 3

[0101] According to the literature report (Adv. Funct. Mater. 2022, 2208994), Ni3S2 was grown on the NF surface. First, nickel foam (surface density: 1500 g / m 2 , thickness: 1cm) Use dilute hydrochloric acid, water, and ethanol ultrasonic cleaning in turn to remove the oxide layer and oil on the surface of the substrate. Dissolve 225mg of thiourea (sulfur source) in 35mL of water and stir evenly. Then, transfer the solution to a 50mL tetrafluoroethylene reactor and put the treated nickel foam into it. Finally, put the reactor in an oven and react at 150℃ for 12h. After the reaction is completed, cool to room temperature, then take out the electrode, rinse with water and ethanol, dry and set aside, and the resulting electrode is marked as Ni3S2 / NF.

[0102] Comparative Example 4

[0103] According to the literature report (J.Electrochem.Soc.2020,106511), MoS2 was electrodeposited on the NF surface. First, nickel foam (surface density: 1500 g / m 2 , thickness: 1cm) were cleaned with dilute hydrochloric acid, water, and ethanol ultrasonically in turn to remove the oxide layer and oil stains on the surface of the substrate. 40mL of a solution containing 10mM, 0.2M KCl (pH ~ 6.8) was transferred to an electrolytic cell, with nickel foam as the working electrode, Ag / AgCl as the reference electrode, and platinum wire as the counter electrode, and electrolyzed at -1.1V vs.Ag / AgCl for 5 minutes. After the deposition is completed, the electrode is taken out, rinsed with water and ethanol, and dried for use. The resulting electrode is marked as MoS2 / NF.

[0104] Comparative Example 5

[0105] This comparative example first adopts the method in comparative example 3 to prepare nickel foam (surface density: 1500g / m 2, thickness: 1 cm) substrate, and then the MoS2 layer was electrodeposited on the electrode using the method in ratio 4. After the deposition was completed, the electrode was taken out, rinsed with water and ethanol, and dried for use. The obtained electrode was marked as MoS2 / Ni3S2 / NF.

[0106] Experimental example

[0107] 1. Hydrogen evolution catalytic performance

[0108] This experimental example tests the hydrogen evolution catalytic performance of the hydrogen evolution materials hydrothermally synthesized at different temperatures in Example 1 in 1M KOH. The test adopts a three-electrode system. In this reaction system, the prepared catalyst is used as the working electrode, the Hg / HgO electrode (0.098V vs. NHE) is the reference electrode, and the platinum wire is the counter electrode. The scan rate is 5mV / s, and manual iR compensation is performed. The test results are shown in the attached Figure 7 It can be seen that the catalysts prepared at several temperatures showed similar hydrogen evolution activities. In contrast, the catalyst prepared at 180 °C showed a low hydrogen evolution activity at 1 A cm -2 The overpotential under these conditions is only 118mV, achieving the best effect.

[0109] This experimental example tests the hydrogen evolution catalytic performance of the hydrogen evolution materials prepared in Examples 1-8 (the hydrothermal temperature is 180°C) in 1M KOH. The test conditions are the same as the above test process and conditions, and the results are shown in the attached Figure 8-9 From the experimental results, it can be seen that the catalytic performance is best when NiCl2 is used as the nickel source, and the catalytic performance is best when DMF is used. From the electron microscope photos, it can be seen that when DMF and ethylene glycol are used as solvents, the specific surface area of ​​the material is the largest, which is consistent with the law of electrocatalytic performance.

[0110] This experimental example tests the hydrogen evolution catalytic performance of the hydrogen evolution material prepared by hydrothermal reaction at 180°C in Example 1 (i.e., Example 1-180°C) in 1M PBS (pH=7.0). The test adopts a three-electrode system. In this reaction system, the prepared catalyst is used as the working electrode, the Ag / AgCl electrode (0.196V vs. NHE) is the reference electrode, and the platinum wire is the counter electrode. The scan rate is 5mV / s, and manual iR compensation is performed. The test results are shown in the attached Fig.10 It can be seen that the hydrogen evolution material of the present invention (Example 1-180°C) can reach 10, 100 and 1000 mA cm under neutral conditions. -2 The required overpotentials were 132, 195, and 305 mV, which are comparable to the effects reported in the literature.

[0111] This experimental example tests the hydrogen evolution catalytic performance of the hydrogen evolution material prepared by hydrothermal reaction at 180°C in Example 1 (i.e., Example 1-180°C) in 1M PBS (pH=9.0). The test adopts a three-electrode system. In this reaction system, the prepared catalyst is used as the working electrode, the Ag / AgCl electrode (0.196V vs. NHE) is the reference electrode, and the platinum wire is the counter electrode. The scan rate is 5mV / s, and manual iR compensation is performed. The test results are shown in the attached Fig.11 It can be seen that the hydrogen evolution material of the present invention (Example 1-180°C) exhibits excellent hydrogen evolution performance under the condition of pH = 9.0, reaching 10, 100 and 1000 mA cm -2 The required overpotentials are 115, 247 and 347 mV.

[0112] 2. Hydrogen evolution stability

[0113] This experimental example tests the hydrogen evolution material prepared in Example 1 (Example 1-180°C) at 1Acm in 1M KOH -2 The test adopts a three-electrode system. In this reaction system, the prepared catalyst is used as the working electrode, the Hg / HgO electrode (0.098V vs. NHE) is used as the reference electrode, the platinum wire is used as the counter electrode, and the current density is 1mA cm -2 , perform manual iR compensation. See the attached test results Fig.12 From the attached Fig.12 It can be seen that the hydrogen evolution material embodiment 1-180℃ at 1mA cm -2 It can work stably for more than 1000h.

[0114] This experimental example tests the hydrogen evolution material prepared in Example 1 (Example 1-180°C) in 1M PBS (pH=7.0) at 1Acm -2 The test adopts a three-electrode system. In this reaction system, the prepared catalyst is used as the working electrode, the Ag / AgCl electrode (0.196V vs. NHE) is used as the reference electrode, the platinum wire is used as the counter electrode, and the current density is 1 mA cm -2 , no iR compensation was performed. See attached for test results Fig.13 From the attached Fig.13 It can be seen that the hydrogen evolution material prepared by the method of the present invention is Example 1-180℃ at 1mA cm -2 It can work stably for more than 550 hours.

[0115] This experimental example tests the hydrogen evolution material prepared in Example 1 (Example 1-180°C) in 1M PBS (pH=9.0) at 1Acm -2The test adopts a three-electrode system. In this reaction system, the prepared catalyst is used as the working electrode, the Ag / AgCl electrode (0.196V vs. NHE) is used as the reference electrode, the platinum wire is used as the counter electrode, and the current density is 1 mA cm -2 , no iR compensation was performed. See attached for test results Fig.14 From the attached Fig.14 It can be seen that the hydrogen evolution material prepared by the method of the present invention is Example 1-180℃ at 1mA cm -2 It can work stably for more than 550 hours.

[0116] 3. Comparison with known catalysts in the prior art

[0117] The information of some MoNi composite materials reported in the prior art (including the simplicity of preparation, raw materials, morphology and specific surface area, etc.) is shown in Table 1 below.

[0118] Table 1 Information on MoNi composite materials reported in the prior art

[0119]

[0120]

[0121] The performance of the samples of the present invention and the hydrogen evolution materials reported in the prior art were tested respectively. The testing method under specific additions was the same as that in Experimental Example 1. The specific test results are shown in Table 2 below.

[0122] Table 2 Comparison of performance and stability of some reported hydrogen evolution catalysts

[0123]

[0124]

[0125] 4. Performance Differences with Comparative Scheme

[0126] In this experiment, the hydrogen evolution catalytic performance of the hydrogen evolution material embodiment 1-180°C and the comparative samples (comparative examples 1-5 materials) in 1M KOH was tested. At the same time, blank nickel foam (Blank NF, surface density 1500g / m 2 , thickness 1cm) for hydrogen evolution performance comparison, the results are attached Fig.15 .

[0127] It can be seen that the hydrogen evolution material of the present invention, although its performance is not as good as that of Pt / C electrode at low current density, can be improved when the catalytic current density is greater than 2.5Acm -2When the catalytic activity is better than that of Pt / C electrode. In addition, the hydrogen evolution material of the present invention has higher catalytic performance than other samples. In other comparative examples, the MoS2 / Ni3S2 grain boundary structure is better than the single MoS2 / NF, Ni3S2 / NF and MoS2 / Ni3S2 / NF layered structure, indicating that the grain boundary structure can effectively improve the catalytic performance; and the hydrogen evolution material of the present invention has higher catalytic performance than that of comparative example 1, indicating that the raw material (NH4)2MoS4 can prepare MoS2 / Ni3S2 catalyst with better catalytic performance.

[0128] In this experiment, the relationship between the capacitance current and the scan rate of the hydrogen evolution material prepared in Example 1 (Example 1-180°C) and the comparative samples (Comparative Examples 2-5 and Blank NF) was tested respectively. The capacitance current was obtained by performing CV scans at different scan rates on all electrode materials in the non-Faraday region (the results are shown in the attached Fig.16 ), and then plot the corresponding scan rate. The slope is C dl . C dl It is directly proportional to the electrochemical active area.

[0129] It can be seen from the data in the figure that the hydrogen evolution material of the present invention has the largest slope (160.5mF ​​cm -2 ), proving that it has the highest electrochemical active area.

[0130] 5. Application performance

[0131] The catalyst performance has been verified, and the preparation method of the present invention can also prepare a catalyst with excellent performance on a nickel mesh (60-300 mesh), and is also easy to scale up (5×5cm 2 ) production, the results are attached Fig.17 . It can be seen from the picture that the catalyst can be enlarged and evenly grown on the nickel foam and the nickel mesh. Obviously, the above embodiments are only examples for clear explanation and are not limitations on the implementation methods. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made on the basis of the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from this are still within the scope of protection of the invention.

Claims

1. A method for preparing nickel-molybdenum-based hydrogen evolution material by one-step hydrothermal synthesis, characterized in that: The method comprises the steps of using (NH4)2MoS4 as a Mo source and a S source and a nickel salt as a nickel source to prepare a MoS2 / Ni3S2 grain boundary by a one-step hydrothermal method; The MoS2 of PDF#37-1492 phase and the Ni3S2 of PDF#44-1418 phase coexist in the grain boundary of the nickel-molybdenum-based hydrogen evolution material MoS2 / Ni3S2; The method for preparing nickel-molybdenum-based hydrogen evolution material by one-step hydrothermal synthesis comprises the following steps: (1) preparing an aqueous solution of (NH4)2MoS4 and a nickel salt solution respectively and mixing them to obtain a suspension; The nickel salt used to prepare the nickel salt solution includes at least one of NiCl2.6H2O, Ni(NO3)2.6H2O, NiSO4.6H2O or Ni(OAc)2.6H2O; The solvent for preparing the nickel salt solution includes at least one of water, N,N-dimethylformamide (DMF), ethylene glycol, isopropanol or N-methylpyrrolidone (NMP); (2) A nickel substrate is added to the suspension to carry out a hydrothermal synthesis reaction, thereby obtaining the desired nickel-molybdenum-based hydrogen evolution material.

2. The method for preparing nickel-molybdenum-based hydrogen evolution material by one-step hydrothermal synthesis according to claim 1, characterized in that: In the step (1), the concentration of the aqueous solution of (NH4)2MoS4 is 10-30 mmol / L.

3. The method for preparing nickel-molybdenum-based hydrogen evolution material by one-step hydrothermal synthesis according to claim 1, characterized in that: In the step (1), the concentration of the nickel salt solution is 3-8 mmol / L.

4. The method for preparing nickel-molybdenum-based hydrogen evolution material by one-step hydrothermal synthesis according to claim 1, characterized in that: In the step (1), the volume ratio of the aqueous solution of (NH4)2MoS4 to the nickel salt solution is 3-8:

1.

5. The method for preparing nickel-molybdenum-based hydrogen evolution material by one-step hydrothermal synthesis according to claim 1, characterized in that: In the step (1), the mixing step includes the step of dropping the nickel salt solution into the aqueous solution of (NH4)2MoS4.

6. The method for preparing nickel-molybdenum-based hydrogen evolution material by one-step hydrothermal synthesis according to claim 5, characterized in that: In the step (1), the dropping time is controlled to be 20-40 minutes.

7. The method for preparing nickel-molybdenum-based hydrogen evolution material by one-step hydrothermal synthesis according to any one of claims 1 to 6, characterized in that: In the step (2), the hydrothermal synthesis reaction step is a closed reaction, the reaction temperature is controlled to be 160-200° C., and the reaction time is 8-24 hours.

8. The method for preparing nickel-molybdenum-based hydrogen evolution material by one-step hydrothermal synthesis according to claim 7, characterized in that: In the step (2), the nickel substrate includes nickel foam or nickel mesh.

9. The method for preparing nickel-molybdenum-based hydrogen evolution material by one-step hydrothermal synthesis according to claim 8, characterized in that: The step (2) also includes the step of cleaning the nickel substrate.

10. The method for preparing nickel-molybdenum-based hydrogen evolution material by one-step hydrothermal synthesis according to claim 9, characterized in that: The step (2) also includes the step of cleaning and / or drying the nickel-molybdenum-based hydrogen evolution material.

11. A nickel-molybdenum-based hydrogen evolution material prepared by the method according to any one of claims 1 to 10; MoS2 of PDF#37-1492 phase and Ni3S2 of PDF#44-1418 phase coexist in the grain boundary of the nickel-molybdenum-based hydrogen evolution material MoS2 / Ni3S2.

12. Use of the nickel-molybdenum-based hydrogen evolution material according to claim 11 for preparing a hydrogen evolution catalyst or a hydrogen evolution electrode.

13. A hydrogen evolution catalyst, a hydrogen evolution electrode, an electrolytic hydrogen evolution device or an electrolytic hydrogen evolution system prepared from the nickel-molybdenum-based hydrogen evolution material according to claim 11.

14. An electrolysis hydrogen process, characterized in that: The method comprises the step of using the nickel-molybdenum-based hydrogen evolution material according to claim 11 as a catalyst for hydrogen evolution electrolysis.

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