A vanadium-doped nickel phosphide material with a spherical micrometer flower-like structure, a preparation method therefor, and an application thereof

Abstract

The application discloses a kind of vanadium doped nickel phosphide material of spherical micrometer flower structure and its preparation method and application, belong to electrolytic water hydrogen production material technical field.Method includes the following steps: (1) foam nickel is ultrasonically cleaned, dry;(2) deionized water, isopropanol, urea, NH4F, VCl3, Ni (NO3) 2·6H2O and the foam nickel treated in step (1) are placed in reaction vessel, heated reaction using hydrothermal method, obtain nickel vanadium oxide grown on foam nickel matrix;(3) nickel vanadium oxide obtained in step (2) and sodium hypophosphite are respectively loaded into porcelain boat, calcine in inert gas atmosphere, obtain vanadium doped nickel phosphide material of spherical micrometer flower structure.Afficient: the vanadium doped nickel phosphide material prepared in the application, according to electrochemical test results, vanadium doped nickel phosphide electrode of spherical micrometer flower structure shows excellent electrocatalytic performance, when current density is 10mA·cm ‑2 , overpotential is only 85mV;It has broad application prospect.

Description

Technical Field

[0001] This invention belongs to the field of materials technology for hydrogen production through water electrolysis, specifically relating to a spherical micron-shaped flower-like structure of vanadium-doped nickel phosphide material, its preparation method, and its application. Background Technology

[0002] The continued growth in energy demand and the environmental pollution caused by the large-scale use of fossil fuels have strongly promoted the development of clean and renewable energy. Hydrogen is a very attractive energy carrier, considered one of the cleanest and most sustainable energy sources, with broad application prospects and a key solution to overcome the current energy crisis. Among existing mature technologies, water electrolysis is an effective method for large-scale hydrogen production.

[0003] Water electrolysis technology relies heavily on the development of electrocatalysts. Electrode materials have a significant impact on the catalytic activity of water electrolysis. However, most catalyst materials have low specific surface areas and few active sites, and their electrocatalytic activity is far from meeting the demands of the rapidly developing energy market. Therefore, designing and developing a highly active and stable electrocatalyst is of great significance. Currently, platinum, a noble metal catalyst, remains the electrode material with the best electrocatalytic hydrogen evolution activity. However, its rarity and high cost in nature limit its large-scale industrial application. Therefore, designing and developing efficient and low-cost non-noble metal catalysts is a current research direction.

[0004] Chinese patent application CN114164448A discloses a heterogeneous nickel phosphide material and its preparation method. The method primarily utilizes the influence of halogens on the nanosheet surface during heat treatment to affect the formation trend of different phases of nickel phosphide, resulting in the formation of Ni2P and Ni5P4 mixed-phase nanocoral structures at different temperatures. After preliminary hydrothermal synthesis of nickel hydroxide nanosheets, a tube furnace heat treatment method is used to introduce halogens as an inducing raw material to regulate the phase composition. By controlling the heat treatment temperature and time, as well as the content of sodium hypophosphite monohydrate and iodine, nanocoral structures with tunable Ni2P and Ni5P4 compositions are successfully synthesized. The water-splitting performance of the material is tested under alkaline conditions. A multi-component nickel phosphide nanocoral is synthesized, and the synergistic effect between the multiple nickel phosphide components significantly improves the catalytic activity for water electrolysis. However, the electrocatalytic activity of the nickel phosphide material in this patent remains relatively low. Summary of the Invention

[0005] The technical problem to be solved by this invention is how to solve the problem of poor electrocatalytic activity of existing electrode materials for water electrolysis.

[0006] The present invention solves the above-mentioned technical problems through the following technical means:

[0007] The first aspect of this invention provides a method for preparing a vanadium-doped nickel phosphide material with a spherical micron-shaped flower-like structure, comprising the following steps:

[0008] (1) Perform ultrasonic cleaning on the nickel foam and then dry it;

[0009] (2) Deionized water, isopropanol, urea, NH4F, VCl3, Ni(NO3)2·6H2O and the foamed nickel obtained in step (1) were placed in a reaction vessel and heated by hydrothermal method to obtain nickel vanadium oxide grown on the foamed nickel substrate.

[0010] (3) The nickel vanadium oxide obtained in step (2) and sodium hypophosphite were respectively loaded into different ceramic boats and calcined in an inert gas atmosphere to obtain vanadium-doped nickel phosphide material with spherical micron flower-like structure.

[0011] Beneficial effects: This invention provides a method for preparing vanadium-doped nickel phosphide materials with spherical micron-shaped flower-like structures, which has significant reference value in the field of hydrogen production through water electrolysis. Furthermore, the vanadium-doped nickel phosphide materials prepared using the method provided by this invention exhibit extremely excellent electrocatalytic activity and broad application prospects.

[0012] Preferably, the ultrasonic cleaning in step (1) is performed at 40 kHz.

[0013] Preferably, the ultrasonic cleaning step (1) specifically involves: first, ultrasonicating with 1 mol / L HCl solution for 20 minutes to remove the oxide layer; then, ultrasonicating with acetone solution for 20 minutes to remove oil stains; finally, ultrasonicating with deionized water and anhydrous ethanol for 10 minutes each to ensure surface cleanliness. After completing the above steps, the cleaned sample is placed in a vacuum drying oven and dried at 60°C for 10 hours.

[0014] Preferably, in step (2), the volume ratio of deionized water to isopropanol is (1-3):(0.5-1.5).

[0015] Preferably, in step (2), the volume ratio of deionized water to isopropanol is 2:1.

[0016] Preferably, in step (2), the mass ratio of urea, NH4F, VCl3, and Ni(NO3)2·6H2O is 1:(0.1-0.4):(0.05-0.2):(0.2-0.8).

[0017] Preferably, the molar ratio of VCl3 to (VCl3+Ni(NO3)2) in step (2) is 14%.

[0018] Preferably, the heating temperature in step (2) is 100-150℃.

[0019] Preferably, the reaction time in step (2) is 12-20 hours.

[0020] Preferably, the mass ratio of nickel vanadium oxide to sodium hypophosphite in step (3) is 1:(15-30).

[0021] Preferably, the calcination temperature in step (3) is 300-400℃ and the time is 1-3h.

[0022] Preferably, the inert gas in step (3) is Ar gas.

[0023] A second aspect of the present invention provides a vanadium-doped nickel phosphide material with a spherical micron-shaped flower-like structure prepared by the above-described preparation method.

[0024] A third aspect of the present invention proposes the application of the above-mentioned spherical micron-shaped flower-like vanadium-doped nickel phosphide material in the field of water electrolysis for hydrogen production.

[0025] The advantages of this invention are:

[0026] Compared with currently reported methods for preparing electrocatalyst materials, this invention has the following outstanding features:

[0027] 1. The vanadium-doped nickel phosphide material prepared by this invention has a unique spherical micron-shaped flower-like structure, with a novel morphology and structure, and the method is simple and effective.

[0028] 2. In the process of preparing vanadium-doped nickel phosphide material according to the present invention, non-precious metals vanadium and nickel are used as raw materials, which greatly reduces the cost of the material.

[0029] 3. The vanadium-doped nickel phosphide material prepared by this invention, according to electrochemical test results, exhibits excellent electrocatalytic performance at a current density of 10 mA·cm⁻¹. -2 At that time, the overpotential was only 85mV.

[0030] Therefore, this invention provides a method for preparing vanadium-doped nickel phosphide materials with spherical micron-shaped flower-like structures, which has significant reference value for the field of hydrogen production through water electrolysis. Furthermore, the vanadium-doped nickel phosphide materials prepared using the method provided by this invention exhibit extremely excellent electrocatalytic activity and broad application prospects. Attached Figure Description

[0031] Figure 1 The image shows the XRD pattern of the vanadium-doped nickel phosphide material with a spherical micron-shaped flower-like structure prepared in Example 1.

[0032] Figure 2 This is a SEM image of the vanadium-doped nickel phosphide material with a spherical micron-shaped flower-like structure prepared in Example 1.

[0033] Figure 3 This is a TEM image of the vanadium-doped nickel phosphide material with a spherical micron-shaped flower-like structure prepared in Example 1.

[0034] Figure 4 SEM image of the vanadium-doped nickel phosphide material with spherical micron-shaped flower-like structure prepared in Comparative Example 1;

[0035] Figure 5 SEM image of the vanadium-doped nickel phosphide material with spherical micron-shaped flower-like structure prepared in Comparative Example 2;

[0036] Figure 6 SEM image of the vanadium-doped nickel phosphide material with spherical micron-shaped flower-like structure prepared in Comparative Example 3;

[0037] Figure 7 SEM image of the vanadium-doped nickel phosphide material with spherical micron-shaped flower-like structure prepared in Comparative Example 4;

[0038] Figure 8 The diagram shows the electrocatalytic hydrogen evolution activity of vanadium-doped nickel phosphide materials with spherical micron-shaped flower-like structures prepared in Examples 1, 1, 2, 3, and 4. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] Unless otherwise specified, all test materials and reagents used in the following examples are commercially available.

[0041] Unless otherwise specified in the embodiments, the techniques or conditions described in the literature in this field or in accordance with the product manual may be followed.

[0042] Example 1:

[0043] A method for preparing vanadium-doped nickel phosphide material with spherical micron-shaped flower-like structures, the specific steps of which are as follows:

[0044] (1) The nickel foam was ultrasonically cleaned at 40 kHz using the following sequence: First, it was ultrasonicated for 20 min with 1 mol / L HCl solution to remove the oxide layer; then, it was ultrasonicated for 20 min with acetone solution to remove oil stains; finally, it was ultrasonicated for 10 min each with deionized water and anhydrous ethanol to ensure surface cleanliness. After the above steps were completed, the cleaned sample was placed in a vacuum drying oven and dried at 60 ℃ for 10 h.

[0045] (2) Prepare 120 mL of a mixed solution of deionized water and isopropanol in a beaker with a volume ratio of 2:1. Weigh 0.4004 g of urea, 0.0978 g of NH4F, 0.0137 g of VCl3 (14%) and 0.1567 g of Ni(NO3)2·6H2O and add them to the mixed solution. Stir magnetically for 10 min to obtain a solution. Transfer the solution to a reaction vessel and place the pretreated nickel foam from step 1 into the reaction vessel. Use a hydrothermal method to react at 120 °C in an oven for 16 h. After the reaction is completed, cool to obtain nickel vanadium oxide grown on the nickel foam substrate.

[0046] (3) The nickel vanadium oxide obtained in step (2) and sodium hypophosphite were loaded into different ceramic boats at a mass ratio of 1:20 and placed in a tube furnace in front and behind positions. Then, the sample was heated in an Ar atmosphere at a rate of 2℃ / min to 350℃ for 2h to obtain the final sample, a vanadium-doped nickel phosphide material with a spherical micron flower-like structure.

[0047] Figure 1 The image shows the XRD pattern of the spherical micron-shaped flower-like vanadium-doped nickel phosphide material prepared in Example 1. After comparison with the PDF standard card, it is found that the vanadium-doped nickel phosphide material is mainly composed of a Ni substrate, Ni2P and Ni5P4, and the vanadium is doped into the Ni lattice.

[0048] Figure 2 and Figure 3 The images show SEM and TEM images of the spherical micron-flower-like vanadium-doped nickel phosphide material prepared in Example 1. As can be seen from the two images, the morphology of the material is a spherical micron-flower-like structure composed of nanosheets, with the micron-flower diameter being about 1-2 μm. The material is generally evenly distributed.

[0049] Comparative Example 1:

[0050] The difference between this comparative example and Example 1 is that VCl3 (0%) is not added in step (2), while the other steps are the same as in Example 1.

[0051] Figure 4 The image shows a SEM image of the vanadium-doped nickel phosphide material with a spherical micron-shaped flower-like structure prepared in Comparative Example 1.

[0052] Comparative Example 2:

[0053] The difference between this comparative example and Example 1 is that 0.00729g of VCl3 (8%) was added in step (2), while the other steps were the same as in Example 1.

[0054] Figure 5 The image shows a SEM image of the vanadium-doped nickel phosphide material with a spherical micron-shaped flower-like structure prepared in Comparative Example 2.

[0055] Comparative Example 3:

[0056] The difference between this comparative example and Example 1 is that 0.0210g of VCl3 (20%) was added in step (2), while the other steps were the same as in Example 1.

[0057] Figure 6 The image shows a SEM image of the vanadium-doped nickel phosphide material with a spherical micron-shaped flower-like structure prepared in Comparative Example 3.

[0058] Comparative Example 4:

[0059] The difference between this comparative example and Example 1 is that 0.0296g of VCl3 (26%) was added in step (2), while the other steps were the same as in Example 1.

[0060] Figure 7 The image shows a SEM image of the vanadium-doped nickel phosphide material with a spherical micron-shaped flower-like structure prepared in Comparative Example 4.

[0061] Figure 8 The figures show the electrocatalytic hydrogen evolution activity of the spherical micron-shaped vanadium-doped nickel phosphide materials prepared in Examples 1, 2, 3, and 4. As can be seen from the figures, the spherical micron-shaped vanadium-doped nickel phosphide materials exhibit excellent electrocatalytic performance. At a current density of 10 mA·cm⁻¹... -2 At that time, the overpotential was only 85mV.

[0062] The electrocatalytic performance of the vanadium-doped nickel phosphide materials prepared in Example 1 and Comparative Examples 1, 2, 3 and 4 was measured, and the results are shown in Table 1 below.

[0063]

[0064] Table 1

[0065] As shown in the table above, compared with Comparative Examples 1, 2, 3, and 4, Example 1 has a uniformly distributed spherical micron flower structure and exhibits the best electrocatalytic performance.

[0066] Example 2:

[0067] A method for preparing vanadium-doped nickel phosphide material with spherical micron-shaped flower-like structures, the specific steps of which are as follows:

[0068] (1) The nickel foam was ultrasonically cleaned at 40 kHz using the following sequence: First, it was ultrasonicated for 20 min with 1 mol / L HCl solution to remove the oxide layer; then, it was ultrasonicated for 20 min with acetone solution to remove oil stains; finally, it was ultrasonicated for 10 min each with deionized water and anhydrous ethanol to ensure surface cleanliness. After the above steps were completed, the cleaned sample was placed in a vacuum drying oven and dried at 60 ℃ for 10 h.

[0069] (2) Prepare 120 mL of a mixed solution of deionized water and isopropanol in a beaker at a volume ratio of 1:0.5; weigh 0.4004 g of urea, 0.0978 g of NH4F, 0.0137 g of VCl3 (14%) and 0.1567 g of Ni(NO3)2·6H2O and add them to the mixed solution, and stir magnetically for 10 min to obtain a solution. Transfer the solution to a reaction vessel, and place the pretreated nickel foam from step 1 horizontally into the reaction vessel. Use a hydrothermal method to react at 100 °C in an oven for 20 h; after the reaction is completed, cool to obtain nickel vanadium oxide grown on the nickel foam substrate.

[0070] (3) The nickel vanadium oxide obtained in step (2) and sodium hypophosphite were loaded into different ceramic boats at a mass ratio of 1:15 and placed in a tube furnace in front and behind positions. Then, the sample was heated in an Ar atmosphere at a rate of 2℃ / min to 300℃ for 3h to obtain the final sample, a vanadium-doped nickel phosphide material with a spherical micron flower-like structure.

[0071] Example 3:

[0072] A method for preparing vanadium-doped nickel phosphide material with spherical micron-shaped flower-like structures, the specific steps of which are as follows:

[0073] (1) The nickel foam was ultrasonically cleaned at 40 kHz using the following sequence: First, it was ultrasonicated for 20 min with 1 mol / L HCl solution to remove the oxide layer; then, it was ultrasonicated for 20 min with acetone solution to remove oil stains; finally, it was ultrasonicated for 10 min each with deionized water and anhydrous ethanol to ensure surface cleanliness. After the above steps were completed, the cleaned sample was placed in a vacuum drying oven and dried at 60 ℃ for 10 h.

[0074] (2) Prepare 120 mL of a mixed solution of deionized water and isopropanol in a volume ratio of 3:1.5 in a beaker; weigh 0.4004 g of urea, 0.0978 g of NH4F, 0.0137 g of VCl3 (14%) and 0.1567 g of Ni(NO3)2·6H2O and add them to the mixed solution, and stir magnetically for 10 min to obtain a solution. Transfer the solution to a reaction vessel, and place the pretreated nickel foam from step 1 horizontally into the reaction vessel. Use a hydrothermal method to react at 150 °C in an oven for 12 h; after the reaction is completed, cool to obtain nickel vanadium oxide grown on the nickel foam substrate.

[0075] (3) The nickel vanadium oxide obtained in step (3) and sodium hypophosphite were loaded into different ceramic boats at a mass ratio of 1:30 and placed in a tube furnace in front and behind positions. Then, the sample was heated in an Ar atmosphere at a rate of 2℃ / min to 400℃ for 1h to obtain the final sample, a vanadium-doped nickel phosphide material with a spherical micron flower-like structure.

[0076] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a vanadium-doped nickel phosphide material with a spherical micron-shaped flower-like structure, characterized in that, Includes the following steps: (1) The nickel foam was ultrasonically cleaned and dried; (2) Deionized water, isopropanol, urea, NH4F, VCl3, Ni(NO3)2·6H2O and the foamed nickel obtained in step (1) are placed in a reaction vessel and heated by hydrothermal method to obtain nickel vanadium oxide grown on the foamed nickel substrate; the volume ratio of deionized water to isopropanol is (1-3):(0.5-1.5); the mass ratio of urea, NH4F, VCl3 and Ni(NO3)2·6H2O is 1:(0.1-0.4):(0.05-0.2):(0.2-0.8); (3) The nickel vanadium oxide and sodium hypophosphite obtained in step (2) are respectively loaded into a ceramic boat and calcined in an inert gas atmosphere to obtain vanadium-doped nickel phosphide material with spherical micron flower-like structure; the vanadium-doped nickel phosphide material is mainly composed of Ni substrate, Ni2P and Ni5P4, and vanadium is doped into the Ni lattice; the mass ratio of nickel vanadium oxide to sodium hypophosphite is 1:(15-30); the calcination temperature is 300-400 ℃ and the time is 1-3 h.

2. The preparation method according to claim 1, characterized in that, The ultrasonic cleaning steps in step (1) are as follows: First, use 1 mol / L HCl solution to sonicate for 20 min to remove the oxide layer; then use acetone solution to sonicate for 20 min to remove oil stains; finally, use deionized water and anhydrous ethanol to sonicate for 10 min respectively to ensure surface cleanliness; after the above steps are completed, put the cleaned sample into a vacuum drying oven and dry it at 60 ℃ for 10 h.

3. The preparation method according to claim 1, characterized in that, In step (2), the volume ratio of deionized water to isopropanol is 2:

1.

4. The preparation method according to claim 1, characterized in that, In step (2), the mass ratio of urea, NH4F, VCl3, and Ni(NO3)2·6H2O is 1:0.4:0.2:0.

8.

5. The preparation method according to claim 1, characterized in that, In step (2), the molar ratio of VCl3:(VCl3+Ni(NO3)2) is 14%.

6. The preparation method according to claim 1, characterized in that, The heating temperature in step (2) is 100-150℃, and the reaction time is 12-20h.

7. The preparation method according to claim 1, characterized in that, The mass ratio of nickel vanadium oxide to sodium hypophosphite in step (3) is 1:

20.

8. The preparation method according to claim 1, characterized in that, The calcination temperature in step (3) is 350℃ and the time is 2 h.

9. A vanadium-doped nickel phosphide material with a spherical micron-shaped flower-like structure prepared by the preparation method according to any one of claims 1-8.

10. The application of the vanadium-doped nickel phosphide material with a spherical micron-shaped flower structure as described in claim 9 in the field of hydrogen production by water electrolysis.

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