Mo-doped NiS micrometer flower electrocatalyst, and preparation method and application thereof

Abstract

The application discloses a Mo-doped NiS micrometer flower electrocatalyst and a preparation method and application thereof, and adopts a one-step hydrothermal-solvothermal method to synthesize a NiS micrometer flower self-supporting electrocatalyst on an industrial metal substrate, namely a porous nickel mesh; firstly, ammonium molybdate tetrahydrate and thioacetamide are simultaneously added into anhydrous ethanol, a small amount of amino carboxylate complexing agent promoting surface growth is added, and a uniform solution is obtained by stirring; a clean porous nickel mesh is immersed into the solution to perform a hydrothermal reaction; and after being cleaned and dried, a Mo-doped NiS micrometer flower structure electrocatalyst is obtained; the method has the characteristics of mild reaction conditions, simple operation, no need of harsh reaction conditions and realization of mass production; the surface morphology of the prepared electrocatalyst is a composite structure of micrometer flowers and nanoparticles grown on the porous nickel mesh; and the material has excellent performance as an alkaline electrocatalytic water splitting hydrogen production catalyst under a large current density.

Description

Technical Field

[0001] This invention belongs to the field of functional materials technology, and relates to electrocatalysts, specifically to a Mo-doped NiS micron-flower electrocatalyst, its preparation method, and its application. Background Technology

[0002] To address the shortage of fossil fuels and improve energy efficiency, the search for green, pollution-free, and sustainable energy sources has become a global research hotspot. Hydrogen, with its clean, efficient, sustainable, and recyclable characteristics, has the potential to replace traditional fossil fuels (such as coal, oil, and natural gas). Water electrolysis is currently the green solution for producing high-purity hydrogen. This process is simple, and the produced hydrogen can be used in electrical energy production. Since the product of consuming hydrogen is still water, it enables the development of a sustainable hydrogen economy. The Hydrogen Evolution Reaction (HER) is a key step in water electrolysis. Currently, the most ideal catalytic electrodes for HER are still noble metal electrodes, primarily Pt and Pt / C. However, the high cost and low HER efficiency of these noble metal electrodes significantly limit the development of water electrolysis processes. Therefore, developing a highly active, low-cost catalytic electrode to reduce the overpotential of the HER reaction and thus reduce energy loss remains a major challenge in the field of electrocatalysis.

[0003] Nickel sulfide (Ni x S y Transition metal sulfides, represented by [missing information], exhibit high activity and stability in the electrocatalytic hydrogen evolution reaction due to their unique morphology and physicochemical properties. Porous nickel mesh, as a common industrial metal substrate, possesses good conductivity and high hardness, but its single-phase catalytic overpotential is relatively high. Currently reported self-supported catalytic electrodes are prepared using materials such as reduced graphene oxide (CN115196694A), nickel foam (CN115700298A), and carbon paper (CN115261911A) as support substrates. The preparation process involves high raw material costs, complex procedures, and cumbersome processes, which is not conducive to the large-scale production of such catalytic electrodes. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a Mo-doped NiS micro-flower electrocatalyst, its preparation method, and its application. A simple one-step hydrothermal-solvothermal method is used to prepare a Mo-doped NiS micro-flower self-supporting electrocatalyst on a porous nickel mesh. This method features low raw material costs, a simple and easily controllable process, and the resulting Mo-doped NiS micro-flower morphology facilitates the exposure of abundant active sites, resulting in excellent electrocatalytic hydrogen evolution performance.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] A method for preparing a Mo-doped NiS micro-flower electrocatalyst includes the following steps:

[0007] Step 1: Take 80 mg of ammonium molybdate tetrahydrate into the liner of a polytetrafluoroethylene reactor, add thioacetamide according to the molar ratio of ammonium molybdate tetrahydrate to thioacetamide (1-1.5):5, then add 10-25 mL of anhydrous ethanol, then add 5 mg of aminocarboxylate complexing agent, and stir evenly.

[0008] Step 2: Immerse the porous nickel mesh in the inner lining of the reactor, cover it with the inner lining lid, put on the outer metal lining of the reactor, and place it in an electric heating drying oven for a solvothermal reaction at a temperature of 150-180℃ for 10-14 hours. After the reaction, wash the sample and let it air dry at room temperature to obtain the Mo-doped NiS micro-flower electrocatalyst.

[0009] Preferably, the aminocarboxylate complexing agent mentioned in step one includes any one of sodium triacetate, ethylenediaminetetraacetate, or diethylenetriaminepentacarboxylate.

[0010] Preferably, the stirring in step one is performed by stirring with a magnetic stirrer for 30 minutes.

[0011] Preferably, the filling ratio of the polytetrafluoroethylene reactor liner in step one is 30% to 60%.

[0012] Preferably, the porous nickel mesh described in step two is cut into pieces with an area of ​​1×5cm. 2 The square.

[0013] Preferably, the washing in step two involves washing with distilled water and ethanol 3 to 5 times respectively.

[0014] The present invention also protects a Mo-doped NiS micro-flower electrocatalyst prepared by the method described above, which has a morphology of a composite structure of NiS micro-flowers and Mo nanoparticles grown on a porous nickel mesh.

[0015] This invention also protects the application of the Mo-doped NiS micro-flower electrocatalyst described above in alkaline water cracking for hydrogen release at high current densities.

[0016] Compared with the prior art, the present invention has the following technical effects:

[0017] This invention employs a simple one-step hydrothermal-solvothermal method to prepare Mo-doped NiS micron-flower electrocatalysts on an industrial metal substrate—a porous nickel mesh. Using the industrial nickel mesh as both the nickel source and conductive substrate improves the overall conductivity of the material, accelerates electron transfer during the reaction, and helps regulate the activity of catalytic sites. The NiS exhibits a micron-flower structure, with fine Mo nanoparticles distributed on the nickel mesh substrate and the micron-flower patterns. This not only effectively increases the exposure of catalytic active sites, but the successful synthesis of the three-dimensional structure also enriches it with abundant composite interfaces that are tightly interconnected, thus enhancing the catalytic activity and stability of the material.

[0018] The product prepared by this invention has a uniform morphology and high purity, and it exhibits excellent performance when used as an electrocatalytic alkaline hydrogen evolution catalyst.

[0019] The present invention has low raw material cost, simple and easy-to-control process, low raw material cost, simple operation and easy process control, no need for large equipment and harsh reaction conditions, adopting a high pressure environment, which not only simplifies the experimental process, but also greatly reduces and shortens the reaction temperature and time. Attached Figure Description

[0020] Figure 1 The XRD pattern of the Mo-doped NiS micro-flower electrocatalyst prepared in Example 1;

[0021] Figure 2 This is a low-magnification SEM image of the Mo-doped NiS micro-flower electrocatalyst prepared in Example 1;

[0022] Figure 3 The image shown is a low-magnification SEM image of the product prepared in Comparative Example 1.

[0023] Figure 4 Here is a high-magnification SEM image of the Mo-doped NiS micro-flower electrocatalyst prepared in Example 1;

[0024] Figure 5 The LSV hydrogen evolution performance curve of the Mo-doped NiS micro-flower electrocatalyst prepared in Example 1 under alkaline conditions. Detailed Implementation

[0025] The specific content of the present invention will be further explained in detail below with reference to the embodiments.

[0026] Example 1:

[0027] Step 1: Weigh 80mg of ammonium molybdate tetrahydrate and thioacetamide and place them in a 50mL clean polytetrafluoroethylene reactor liner, controlling the molar ratio to be 1:5. Add 20mL of anhydrous ethanol and 5mg of EDTA, place a rotating magnetic stirrer, and stir on a magnetic stirrer for 30min.

[0028] Step 2: Remove and rotate the magnet, with an area of ​​1×5cm. 2 The porous nickel mesh was immersed in the lining solution, covered, assembled into a metal outer vessel, and placed in an electric heating drying oven for a solvothermal reaction at a reaction temperature of 160℃ for 12 hours. After filtration and washing with distilled water and ethanol five times each, the product was naturally dried at room temperature to obtain the Mo-doped NiS micro-flower electrocatalyst.

[0029] Figure 1 The XRD pattern of the Mo-doped NiS micro-flower electrocatalyst prepared in Example 1; from Figure 1 It can be seen that, in addition to the characteristic peaks of Ni at 44.5°, 51.8°, and 76.4°, the characteristic peaks of NiS are shown at 18.5°, 30.3°, 32.2°, 35.7°, 40.5°, 48.8°, 50.2°, 52.6°, 56.3°, 57.4°, 59.7°, and 72.6°, proving the successful preparation of the NiS phase.

[0030] Figure 2 Low-magnification SEM image of the Mo-doped NiS micro-flower electrocatalyst prepared in Example 1; from Figure 2 The low-magnification SEM images show that a self-supporting three-dimensional composite structure of NiS micron flakes and fine Mo nanoparticles was grown in situ on an industrial nickel mesh substrate.

[0031] Figure 4 Here is a high-magnification SEM image of the Mo-doped NiS micro-flower electrocatalyst prepared in Example 1; from Figure 4 The high-magnification SEM images show that this micron-shaped flower-like structure has a large specific surface area. Fine Mo nanoparticles are distributed uniformly and randomly on the nickel mesh substrate and NiS micron-shaped flowers, which is beneficial to the exposure of active sites and the improvement of the catalytic stability of the material.

[0032] Figure 5 The LSV hydrogen evolution performance curve of the Mo-doped NiS micro-flower electrocatalyst prepared in Example 1 under alkaline conditions; from Figure 5 As can be seen, this catalyst exhibits excellent electrocatalytic activity under alkaline conditions (pH=14), requiring only 299mV overpotential to reach 400mA / cm. 2 The current density.

[0033] Example 2:

[0034] Step 1: Weigh 80mg of sodium molybdate and thioacetamide and place them in a 50mL clean polytetrafluoroethylene reactor liner, controlling the molar ratio to be 1:5. Add 10mL of anhydrous ethanol and 5mL of NTA and place the magnetic stir bar in the reactor. Stir for 30min on a magnetic stirrer.

[0035] Step 2: Remove and rotate the magnet, with an area of ​​1×5cm. 2 The porous nickel mesh was immersed in the lining solution, covered, assembled into a metal outer vessel, and placed in an electric heating drying oven for a solvothermal reaction at a reaction temperature of 160℃ for 12 hours. After filtration and washing three times with distilled water and ethanol respectively, the product was naturally dried at room temperature to obtain the Mo-doped NiS micro-flower electrocatalyst.

[0036] Example 3:

[0037] Step 1: Weigh 80 mg of ammonium molybdate tetrahydrate and thioacetamide and place them in a 50 mL clean polytetrafluoroethylene reactor liner, controlling the molar ratio of their substances to be 1.3:5. Add 15 mL of anhydrous ethanol and 5 mg of NTA, place a rotating magnetic stirrer, and stir on a magnetic stirrer for 30 min.

[0038] Step 2: Remove and rotate the magnet, with an area of ​​1×5cm. 2 The porous nickel mesh was immersed in the lining solution, the lid was put on, the metal outer vessel was assembled and placed in an electric heating drying oven for a solvothermal reaction at a reaction temperature of 170℃ and a reaction time of 11h. After filtration and washing with distilled water and ethanol four times respectively, the product was naturally dried at room temperature to obtain the Mo-doped NiS micro-flower electrocatalyst.

[0039] Example 4:

[0040] Step 1: Weigh 80mg of sodium molybdate and thioacetamide and place them in a clean polytetrafluoroethylene reactor liner, controlling the molar ratio to be 1.5:5. Add 20mL of anhydrous ethanol and 5mg of EDTA, and place a rotating magnetic stirrer on the reactor. Stir for 30min.

[0041] Step 2: Remove and rotate the magnet, with an area of ​​1×5cm. 2 The porous nickel mesh was immersed in the lining solution, the lid was put on, the metal outer vessel was assembled and placed in an electric heating drying oven for a solvothermal reaction at a reaction temperature of 170℃ and a reaction time of 10h. After filtration and washing with distilled water and ethanol five times respectively, it was naturally dried at room temperature to obtain the Mo-doped NiS micro-flower electrocatalyst.

[0042] Example 5:

[0043] Step 1: Weigh 80 mg of ammonium molybdate tetrahydrate and thioacetamide and place them in a clean polytetrafluoroethylene reactor liner, controlling the molar ratio to be 1.5:5. Add 25 mL of anhydrous ethanol and 5 mg of DTPA, and place a rotating magnetic stirrer on the reactor. Stir for 30 min.

[0044] Step 2: Remove and rotate the magnet, with an area of ​​1×5cm.2 The porous nickel mesh was immersed in the lining solution, covered, assembled into a metal outer vessel, and placed in an electric heating drying oven for a solvothermal reaction at a reaction temperature of 150℃ for 14 hours. After filtration and washing three times with distilled water and ethanol respectively, the product was naturally dried at room temperature to obtain the Mo-doped NiS micro-flower electrocatalyst.

[0045] Example 6:

[0046] Step 1: Weigh 80mg of sodium molybdate and thioacetamide and place them in a clean polytetrafluoroethylene reactor liner, controlling the molar ratio to be 1.2:5. Add 20mL of anhydrous ethanol and 5mg of DTPA, and place a rotating magnetic stirrer on the reactor. Stir for 30min.

[0047] Step 2: Remove and rotate the magnet, with an area of ​​1×5cm. 2 The porous nickel mesh was immersed in the lining solution, covered, assembled into a metal outer vessel, and placed in an electric heating drying oven for a solvothermal reaction at a reaction temperature of 180℃ for 13 hours. After filtration and washing with distilled water and ethanol five times each, the product was naturally dried at room temperature to obtain the Mo-doped NiS micro-flower electrocatalyst.

[0048] Comparative Example 1:

[0049] Step 1: Weigh 80mg of ammonium molybdate tetrahydrate and thioacetamide and place them in a clean polytetrafluoroethylene reactor liner, controlling the molar ratio to be 1:5. Add 20mL of anhydrous ethanol and place a rotating magnetic stirrer on the reactor. Stir for 30min on a magnetic stirrer.

[0050] Step 2: Remove and rotate the magnet, with an area of ​​1×5cm. 2 The porous nickel mesh was immersed in the lining solution, the lid was put on, the metal outer vessel was assembled and placed in an electric heating drying oven for a solvothermal reaction at a reaction temperature of 160℃ for 12h. After filtration and washing with distilled water and ethanol five times each, the product was naturally dried at room temperature.

[0051] Figure 3 The low-magnification SEM image of the product prepared in Comparative Example 1; from Figure 3 The SEM images of the control group show that, without the action of the aminocarboxylate complexing agent, the three-dimensional micron flower and nanoparticle composite structure cannot be formed. Instead, a film-like substance is formed attached to the industrial nickel mesh.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of the claims.

Claims

1. A method for preparing Mo-doped NiS micrometer flower electrocatalyst, characterized in that, It comprises the following steps: Step one, taking 80 mg of ammonium molybdate tetrahydrate in a polytetrafluoroethylene reactor liner, adding thioacetamide according to the molar ratio of ammonium molybdate tetrahydrate to thioacetamide (1-1.5):5, then adding 10-25 mL of anhydrous ethanol, and then adding 5 mg of aminocarboxylate complexing agent, and stirring uniformly; the filling ratio of the polytetrafluoroethylene reactor liner is 30%-60%; Step two, immerse the porous nickel mesh in the reactor liner, cover the liner cover, and cover the reactor metal outer liner, and then place it in an electric heating drying oven for solvothermal reaction at a reaction temperature of 150-180°C for 10-14 h; after the reaction is completed, wash the sample and naturally dry it at room temperature to obtain the Mo-doped NiS micrometer flower electrocatalyst.

2. The method for preparing Mo-doped NiS micrometer flower electrocatalyst according to claim 1, characterized in that, The aminocarboxylate complexing agent in step one includes any one of sodium nitrilotriacetate, ethylenediaminetetraacetate, or diethylenetriamine pentacarboxylate.

3. The method for preparing Mo-doped NiS micrometer flower electrocatalyst according to claim 1, characterized in that, The stirring in step one is magnetic stirring for 30 min.

4. The method of claim 1, wherein the Mo-doped NiS microfower electrocatalyst is prepared by the following steps: (1) preparing a Mo-doped NiS precursor by a solvothermal method; (2) preparing a Mo-doped NiS microfower electrocatalyst by a hydrothermal method. The porous nickel mesh described in Step two was cut into a square with an area of 1 x 5 cm 2 .

5. The method of claim 1, wherein the Mo-doped NiS microflower electrocatalyst is prepared by the following steps: (1) preparing a Mo-doped NiS precursor by a chemical reduction method; (2) preparing a Mo-doped NiS microflower electrocatalyst by a hydrothermal method. The washing in step two is washing with distilled water and ethanol for 3-5 times, respectively.

6. A Mo-doped NiS micrometer flower electrocatalyst prepared by the method of any one of claims 1 to 5, characterized in that, The morphology is a composite structure of NiS micrometer flower and Mo nanoparticles grown on the porous nickel mesh.

7. Use of the Mo-doped NiS micrometer flower electrocatalyst according to claim 6 in alkaline water splitting to analyze hydrogen at a large current density.

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