Transition metal phosphide electrode material and preparation method thereof

Abstract

The invention relates to the field of electrocatalysts, in particular to a transition metal phosphide electrode material and a preparation method thereof. A ZIF type metal organic framework material is formed through a coordination reaction of a precursor with a two-dimensional nanosheet array structure and dimethylimidazole, and an array with a large specific surface area and a two-dimensional nanosheet structure is formed by utilizing a three-dimensional space structure of the ZIF type metal organic framework material, so that more catalytic sites of a hydrogen evolution reaction are increased; the transition metal phosphide electrode material prepared by the invention has relatively high catalytic hydrogen evolution performance. Meanwhile, an organic ligand in the ZIF type metal organic framework material can form a protection effect on a catalytic site of a hydrogen evolution reaction, so that the transition metal phosphide electrode material prepared by the preparation method has relatively high stability and relatively long service life; therefore, the technical problem that an existing transition metal compound is poor in catalytic hydrogen evolution performance is solved.

Description

Technical Field

[0001] The present invention relates to the field of electrocatalysts, and particularly to a transition metal phosphide electrode material and a preparation method thereof. Background Art

[0002] In recent years, with the overuse of fossil energy and the increasing environmental pollution, the application of various new energy sources has been vigorously developed. Among them, hydrogen energy, as an energy source with great potential, has come into people's view. The main way to obtain hydrogen is to construct a suitable electrolysis system to electrolyze water.

[0003] The reaction process of water electrolysis consists of two half-reactions, namely the oxygen evolution reaction at the anode and the hydrogen evolution reaction at the cathode. Among them, oxygen can be obtained from the oxygen evolution reaction at the anode, and hydrogen can be obtained from the hydrogen evolution reaction at the cathode. During the process of the hydrogen evolution reaction at the cathode, the migration of 2 electrons will occur, but during the process of the oxygen evolution reaction at the anode, the migration of 4 electrons will occur. Therefore, the kinetic process of the anode reaction will be hindered, resulting in the necessity to introduce a kinetic barrier, that is, an activation energy barrier. When these energy barriers accumulate, they will cause the voltage required for actual water electrolysis to exceed the theoretical voltage value of 1.23 V. The voltage exceeding the theoretical voltage is called overpotential. Using an electrode material with catalytic hydrogen evolution as the cathode can effectively reduce the overpotential, reduce the working voltage of water electrolysis, and effectively reduce energy consumption.

[0004] Using metallic platinum as the electrode material can provide excellent catalytic performance, but the scarcity and high price of metallic platinum limit its application in the hydrogen evolution reaction of water electrolysis. Due to the rich reserves and relatively low price, the application of transition metal compounds in the field of hydrogen evolution by water electrolysis has received extensive attention. However, the existing transition metal compounds have poor catalytic hydrogen evolution performance and are difficult to meet the requirements of hydrogen production by water electrolysis reaction. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art, and provide a transition metal phosphide electrode material and a preparation method thereof, which ingeniously solve the technical problem that the existing transition metal compounds have poor catalytic hydrogen evolution performance.

[0006] To achieve the above object, the present invention adopts the following technical solutions: The present invention provides a preparation method of a transition metal phosphide electrode material, which is characterized by including the steps: At room temperature, a precursor with a two-dimensional nanosheet array structure is subjected to a coordination reaction with dimethylimidazole to form a ZIF-type metal-organic framework material; the ZIF-type metal-organic framework material and hypophosphite are calcined to form an array of two-dimensional nanosheet structures with a large specific surface area, and a transition metal phosphide electrode material is prepared; the precursor is prepared by reacting a mixed solution of a transition metal salt, ammonium fluoride, and urea on a nickel foam substrate; the transition metal in the transition metal salt is at least two of Fe, Co, Ni, Cu, Zn, Mo, and W.

[0007] In the present invention, a ZIF-type metal-organic framework material is formed by the coordination reaction of a precursor with a two-dimensional nanosheet array structure and dimethylimidazole, and an array of two-dimensional nanosheet structures with a large specific surface area is formed by utilizing the three-dimensional space structure of the ZIF-type metal-organic framework material, thereby increasing more catalytic sites for the hydrogen evolution reaction, so that the transition metal phosphide electrode material prepared in the present invention has high catalytic hydrogen evolution performance. At the same time, the organic ligand in the ZIF-type metal-organic framework material can form a protective effect on the catalytic sites of the hydrogen evolution reaction, so that the transition metal phosphide electrode material prepared in the present invention has high stability and a long lifespan, thus solving the technical problem of poor catalytic hydrogen evolution performance of existing transition metal compounds.

[0008] Optionally, the molar ratio of the precursor to the dimethylimidazole is 1:35 to 60.

[0009] Optionally, the molar ratio of the ZIF-type metal-organic framework material to the hypophosphite is 1:10.

[0010] Optionally, the calcination treatment includes the following steps: heating to 250°C to 350°C and holding for 1 h to 3 h.

[0011] Optionally, the preparation steps of the precursor include: Disperse at least two transition metal salts, ammonium fluoride, and urea in a solvent to obtain a mixed solution; immerse the nickel foam substrate in the mixed solution and heat to react to form a two-dimensional nanosheet array structure, thereby obtaining the precursor; wherein, the heating temperature is 90°C to 130°C, and the heating time is 4 h to 8 h.

[0012] Optionally, the molar ratio of the at least two transition metal salts, the ammonium fluoride, and the urea is 3 to 4:1:25 to 26.

[0013] Optionally, the solvent includes at least one of deionized water, methanol, and ethanol.

[0014] Optionally, the nickel foam substrate is prepared by first performing ultrasonic pickling on nickel foam and then performing ultrasonic water washing.

[0015] Optionally, when the precursor and 2-methylimidazole are in contact reaction by coordination, the standing time is 2 h to 4 h.

[0016] The present invention provides a transition metal phosphide electrode material, which is prepared by using the preparation method of the above-mentioned transition metal phosphide electrode material.

[0017] The beneficial effects of the present invention are as follows. Compared with the prior art, in the present invention, a precursor with a two-dimensional nanosheet array structure reacts with 2-methylimidazole by coordination to form a ZIF-type metal-organic framework material, and by utilizing the three-dimensional spatial structure of the ZIF-type metal-organic framework material, an array with a two-dimensional nanosheet structure having a large specific surface area is formed after phosphidation, thereby increasing more catalytic sites for the hydrogen evolution reaction, so that the transition metal phosphide electrode material prepared by the present invention has high catalytic hydrogen evolution performance. At the same time, the organic ligand in the ZIF-type metal-organic framework material can form a protective effect on the catalytic sites of the hydrogen evolution reaction, so that the transition metal phosphide electrode material prepared by the present invention has high stability and a long service life, thereby solving the technical problem of poor catalytic hydrogen evolution performance of existing transition metal compounds.

[0018] In addition, in the present invention, the precursor is prepared by a low-temperature solvothermal method, and the coordination reaction between the precursor and 2-methylimidazole is a room-temperature coordination reaction. The required reaction conditions are relatively simple, the reaction process is relatively mild and controllable, which is beneficial to the popularization and application of the preparation method. Description of the Drawings

[0019] Figure 1 It is a scanning electron microscope test image of CoZnP prepared in Example 2. Among them, (a) is an image with a low magnification, Figure 1 and (b) in it is an image with a high magnification.

[0020] Figure 2 It is an X-ray diffraction image of a precursor, a ZIF-type metal-organic framework material and CoZnP provided by the present invention. Among them, (a) is the X-ray diffraction image of the precursor, (b) is the X-ray diffraction image of the ZIF-type metal-organic framework material, and (c) is the X-ray diffraction image of CoZnP.

[0021] Figure 3 It is a comparative linear polarization curve diagram of a catalytic hydrogen evolution process provided by the present invention.

[0022] Figure 4 It is another comparative linear polarization curve diagram of a catalytic hydrogen evolution process provided by the present invention.

[0023] Figure 5 It is a comparison diagram of electrochemical impedance spectroscopy images for the catalytic hydrogen evolution process provided by the present invention.

[0024] Figure 6 It is another comparison diagram of electrochemical impedance spectroscopy images for the catalytic hydrogen evolution process provided by the present invention. Detailed implementation manners

[0025] To solve the above technical problems, the present invention provides a transition metal phosphide electrode material and a preparation method thereof. Now, the technical solutions and embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0026] The present invention will be described in detail below through specific embodiments. The embodiments are exemplary and are intended to explain the present invention, but should not be construed as a limitation to the present invention.

[0027] Specifically, the reagents used in the specific embodiments are shown in the following table: In the following embodiments, unless otherwise specified, the methods are all conventional methods; the reagents and materials, unless otherwise specified, can all be purchased on the market.

[0028] Example 1 This embodiment provides a transition metal phosphide electrode material, and the preparation method is as follows: Step 1, preparation of the precursor.

[0029] Take 0.22 g of zinc nitrate hexahydrate, 0.44 g of cobalt nitrate hexahydrate, 0.22 g of ammonium fluoride, and 0.9 g of urea, dissolve them in 60 ml of deionized water, continuously stir at room temperature for 10 min. After stirring evenly, a mixed solution is prepared.

[0030] Cut a foam nickel with a specification of 1 cm × 3 cm, first perform acid washing on the cut foam nickel, and then perform water washing to obtain a foam nickel substrate.

[0031] Add the mixed solution and the foam nickel substrate into the reaction kettle in sequence, continuously heat for 6 h, the heating temperature is 120 °C, collect the product for cleaning, and vacuum dry to obtain the precursor.

[0032] Step 2, preparation of the ZIF-type metal-organic framework material.

[0033] Take 1.25 g of dimethylimidazole and dissolve it in 20 mL of deionized water, stir evenly to obtain a dimethylimidazole solution.

[0034] Add the precursor prepared in Step 1 into the dimethylimidazole solution, make full contact, stand for 3 h, then take out the product for cleaning and vacuum drying to obtain the ZIF-type metal-organic framework material.

[0035] Step 3, Preparation of the catalyst.

[0036] Place the ZIF-type metal-organic framework material prepared in Step 2 downstream of the tube furnace, and weigh 0.5 g of sodium hypophosphite and place it upstream of the tube furnace. Under the condition of introducing argon, heat the tube furnace to 300 °C at a rate of 2 °C / min, and maintain it for 2 h under an argon flow. After cooling to room temperature, CoZnP is obtained.

[0037] Example 2 This example provides a transition metal phosphide electrode material, and the preparation method is as follows: Step 1, Preparation of the precursor Take 0.22 g of zinc nitrate hexahydrate, 0.44 g of cobalt nitrate hexahydrate, 0.22 g of ammonium fluoride, and 0.9 g of urea, dissolve them in 60 ml of deionized water, continuously stir at room temperature for 10 min. After stirring evenly, a mixed solution is obtained.

[0038] Cut a foam nickel with a specification of 1 cm × 3 cm, first perform pickling on the cut foam nickel, and then perform water washing to obtain a foam nickel substrate.

[0039] Add the mixed solution and the foam nickel substrate into the reaction kettle in sequence, continuously heat for 6 h, the heating temperature is 120 °C, collect the product for cleaning, and vacuum dry to obtain the precursor.

[0040] Step 2, Preparation of the ZIF-type metal-organic framework material Take 1.25 g of dimethylimidazole and dissolve it in 20 mL of deionized water, stir evenly to obtain a dimethylimidazole solution.

[0041] Add the precursor prepared in Step 1 into the dimethylimidazole solution, make full contact, stand for 3 h, then take out the product for cleaning and vacuum drying to obtain the ZIF-type metal-organic framework material.

[0042] Step 3, Preparation of the catalyst Place the ZIF-type metal-organic framework material prepared in Step 2 downstream of the tube furnace, and weigh 1 g of sodium hypophosphite and place it upstream of the tube furnace. Under the condition of introducing argon, heat the tube furnace to 300 °C at a rate of 2 °C / min, and maintain it for 2 h under an argon flow. After cooling to room temperature, CoZnP is obtained.

[0043] Example 3 This example provides a transition metal phosphide electrode material, and the preparation method is as follows: Step 1, Preparation of the precursor Dissolve 0.22 g of zinc nitrate hexahydrate, 0.44 g of cobalt nitrate hexahydrate, 0.22 g of ammonium fluoride, and 0.9 g of urea in 60 ml of deionized water. Stir continuously at room temperature for 10 min. After stirring evenly, a mixed solution is prepared.

[0044] Cut foam nickel with a specification of 1 cm × 3 cm. First, perform pickling on the cut foam nickel, and then perform water washing to obtain a foam nickel substrate.

[0045] Add the mixed solution and the foam nickel substrate to the reaction kettle in sequence. Heat continuously for 6 h, and the heating temperature is 120 °C. Collect the product, wash it, and dry it in vacuum to obtain a precursor.

[0046] Step 2: Preparation of ZIF-based metal-organic framework material Dissolve 1.25 g of dimethylimidazole in 20 mL of deionized water and stir evenly to obtain a dimethylimidazole solution.

[0047] Add the precursor prepared in Step 1 to the dimethylimidazole solution, make full contact, and let it stand for 3 h. Then take out the product, wash it, and dry it in vacuum to obtain the ZIF-based metal-organic framework material.

[0048] Step 3: Preparation of catalyst Place the ZIF-based metal-organic framework material prepared in Step 2 downstream of the tube furnace, and weigh 1.5 g of sodium hypophosphite and place it upstream of the tube furnace. Under the condition of introducing argon, heat the tube furnace to 300 °C at a rate of 2 °C / min, and keep it for 2 h under the argon flow. After cooling to room temperature, CoZnP is obtained.

[0049] Comparative Example 1 This example provides a foam nickel substrate, and the preparation method is as follows: Cut foam nickel with a specification of 1 cm × 3 cm. First, perform pickling on the cut foam nickel, and then perform water washing to obtain a foam nickel substrate.

[0050] Comparative Example 2 This example provides a precursor, and the preparation method is as follows: Dissolve 0.22 g of zinc nitrate hexahydrate, 0.44 g of cobalt nitrate hexahydrate, 0.22 g of ammonium fluoride, and 0.9 g of urea in 60 ml of deionized water. Stir continuously at room temperature for 10 min. After stirring evenly, a mixed solution is prepared.

[0051] Cut foam nickel with a specification of 1 cm × 3 cm. First, perform pickling on the cut foam nickel, and then perform water washing to obtain a foam nickel substrate.

[0052] Add the mixed solution and the foam nickel substrate to the reaction kettle in sequence. Heat continuously for 6 h, and the heating temperature is 120 °C. Collect the product, wash it, and dry it in vacuum to obtain a precursor.

[0053] Comparative Example 3 This example provides a ZIF-type metal-organic framework material, and the preparation method is as follows: Step 1, Preparation of the precursor Take 0.22 g of zinc nitrate hexahydrate, 0.44 g of cobalt nitrate hexahydrate, 0.22 g of ammonium fluoride, and 0.9 g of urea, dissolve them in 60 ml of deionized water, continuously stir at room temperature for 10 min. After stirring evenly, a mixed solution is obtained.

[0054] Cut a foam nickel with a specification of 1 cm × 3 cm, first perform pickling on the cut foam nickel, and then perform water washing to obtain a foam nickel substrate.

[0055] Add the mixed solution and the foam nickel substrate into the reaction kettle in sequence, continuously heat for 6 h, the heating temperature is 120 °C, collect the product for cleaning, and vacuum dry to obtain the precursor.

[0056] Step 2, Preparation of the ZIF-type metal-organic framework material Take 1.25 g of dimethylimidazole and dissolve it in 20 mL of deionized water, stir evenly to obtain a dimethylimidazole solution.

[0057] Add the precursor prepared in Step 1 into the dimethylimidazole solution, make full contact, stand for 3 h, then take out the product for cleaning and vacuum dry to obtain the ZIF-type metal-organic framework material.

[0058] Scanning electron microscope test results: Figure 1 It is an image obtained by performing a scanning electron microscope test on CoZnP prepared in Example 2. Among them, Figure 1 in (a) is a low magnification image, Figure 1 in (b) is a high magnification image.

[0059] From Figure 1 in the (a) figure, it can be seen that the surface of CoZnP is relatively uniform, dense and flat, making its structure relatively stable during the catalytic process, which is beneficial to adsorption and improve the catalytic performance.

[0060] In Figure 1 in the (b) figure, it can be directly seen that the surface of the sample is an array of two-dimensional nanosheet structures, and the thickness of the two-dimensional nanosheet structures is about 100 nm to 200 nm.

[0061] The nanosheet structure has many advantages in the catalytic process, such as a large specific surface area, which forms a large contact area with the electrolyte during the electrolytic catalysis process and can also provide more catalytic sites to improve the catalytic performance. At the same time, the overlapping nanosheet structure can form a stable three-dimensional structure, which can provide good stability for the transition metal phosphide material in the catalytic reaction.

[0062] In summary, the transition metal phosphide electrode material prepared by the present invention has the advantages of a flat and dense surface, a large specific surface area, and a stable structure, which meet the conditions required for improving the catalytic hydrogen evolution efficiency.

[0063] X-ray diffraction test results: Figure 2 It is an image of XRD tests on the precursor, ZIF-type metal-organic framework material, and CoZnP and a comparison with the standard cards of Co(OH)2 (PDF#02-0925), ZIF-67, and CoP4 (PDF#20-0336). Among them, the precursor is labeled as NF-ZnCo in the figure, the ZIF-type metal-organic framework material is labeled as ZIF in the figure, and CoZnP is labeled as ZIF-P in the figure.

[0064] Figure 2 The black curve in the (a) figure of... is the diffraction image of the precursor. Figure 2 The blue curve in the (a) figure of... is the Co(OH)2 standard PDF (PDF#02-0925) card. By comparison, the several main peaks of the black curve at diffraction angles of 32°, 37°, and 58° correspond to the (101), (002), and (110) crystal planes of the cobalt hydroxide PDF standard card, indicating that the precursor exists in the form of cobalt hydroxide. There is a peak shift in the image because zinc elements are doped in the sample.

[0065] Figure 2 The black curve in the (b) figure of... is the diffraction image of the ZIF-type metal-organic framework material. Figure 2 The blue curve in the (b) figure of... is the ZIF-67 standard PDF card. By comparison, the black curve has peaks corresponding to the blue curve at diffraction angles of 13°, 18°, and 32.5°, indicating that the product exists in the structure of the ZIF-type metal-organic framework material.

[0066] Figure 2 The black curve in the (c) figure of... is the diffraction image of CoZnP. Figure 2The blue curve in Figure (c) is the CoP4 standard PDF (PDF#20 - 0336) card. By comparison, the main peaks of the black curve at diffraction angles of 33.0°, 36.9°, and 58.8° correspond to the (220), (310), and (422) crystal planes of the cobalt phosphide PDF standard card, indicating that phosphorus elements are incorporated into the final sample. The above X - ray diffraction image shows that the preparation method of the transition metal phosphide electrode material provided by the present invention can prepare a transition metal phosphide electrode material with a ZIF - type metal - organic framework material structure.

[0067] Electrochemical performance test and results: Linear sweep voltammetry test and results: (1) The test system is a three - electrode system: Using the nickel foam substrate prepared in Comparative Example 1, the precursor prepared in Comparative Example 2, the ZIF - type metal - organic framework material prepared in Comparative Example 3, and CoZnP prepared in Example 1 as the working electrode, a carbon electrode as the auxiliary electrode, a Hg / HgO electrode as the reference electrode, and a 0.5 mol / L NaOH solution as the electrolyte, a linear sweep voltammetry test is carried out, and a linear sweep voltammetry curve image is plotted, as Figure 3 shown. Among them, the nickel foam substrate prepared in Comparative Example 1 is labeled as NF in the figure, the precursor prepared in Comparative Example 2 is labeled as NF - ZnCo in the figure, the ZIF - type metal - organic framework material prepared in Comparative Example 3 is labeled as ZIF in the figure, and CoZnP prepared in Example 1 is labeled as ZIF - 0.5P in the figure.

[0068] It can be seen from Figure 3 that under the condition of the same current density of 0.1 A / cm 2 , when using CoZnP of Example 1 to catalyze hydrogen evolution, the over - potential measured is 0.41 V; when using the nickel foam substrate to catalyze hydrogen evolution, the over - potential measured is 0.45 V; when using the ZIF - type metal - organic framework material to catalyze hydrogen evolution, the over - potential measured is 0.42 V; when using the precursor to catalyze hydrogen evolution, the over - potential measured is 0.43 V. Among them, the over - potential of Example 1 is significantly the best, from which it can be judged that the transition metal phosphide electrode material has the best catalytic hydrogen evolution performance.

[0069] (2) The test system is a three - electrode system: Using the ZIF - type metal - organic framework material prepared in Comparative Example 3, CoZnP prepared in Example 1, CoZnP prepared in Example 2, and CoZnP prepared in Example 3 as the working electrode, a carbon electrode as the auxiliary electrode, a Hg / HgO electrode as the reference electrode, and a 0.5 mol / L NaOH solution as the electrolyte, a linear sweep voltammetry test is carried out, and a linear sweep voltammetry curve image is plotted, as Figure 4As shown. Among them, the ZIF-type metal-organic framework material prepared in Comparative Example 3 is labeled as ZIF in the figure, the CoZnP prepared in Example 1 is labeled as ZIF-0.5P in the figure, the CoZnP prepared in Example 2 is labeled as ZIF-P in the figure, and the CoZnP prepared in Example 3 is labeled as ZIF-1.5P in the figure.

[0070] It can be seen that Figure 4 under the condition of the same current density of 0.1 A / cm 2 , the overpotential measured in Example 1 is 0.41 V; the overpotential measured in Example 2 is 0.38 V; the overpotential measured in Example 3 is 0.4 V; the overpotential measured in Comparative Example 3 is 0.42 V. Among them, the overpotential of Example 2 is significantly the best.

[0071] Electrochemical impedance spectroscopy test and results: (1) The test system is a three-electrode system: Using the nickel foam substrate prepared in Comparative Example 1, the precursor prepared in Comparative Example 2, the ZIF-type metal-organic framework material prepared in Comparative Example 3, and the CoZnP prepared in Example 1 as the working electrode, a carbon electrode as the auxiliary electrode, a Hg / HgO electrode as the reference electrode, and a 0.5 mol / L NaOH solution as the electrolyte, an electrochemical impedance spectroscopy test was carried out, and an impedance spectrum was plotted, as Figure 5 shown. Among them, the nickel foam substrate prepared in Comparative Example 1 is labeled as NF in the figure, the precursor prepared in Comparative Example 2 is labeled as NF-ZnCo in the figure, the ZIF-type metal-organic framework material prepared in Comparative Example 3 is labeled as ZIF in the figure, and the CoZnP prepared in Example 1 is labeled as ZIF-0.5P in the figure.

[0072] It can be seen that Figure 5 the impedance radius of Example 1 is the smallest, and the impedance is 61 Ω. The impedance spectrum radii of Comparative Example 3 and Comparative Example 2 increase in turn, and the impedances are 100 Ω and 105 Ω in turn, while the impedance diagram radius of Comparative Example 1 is the largest and the impedance value is the largest. It shows that the transition metal phosphide electrode material has the smallest impedance and the best hydrogen evolution catalytic performance during the catalytic hydrogen evolution process. This corresponds to the results of the above SEM images. The ZIF-type metal-organic framework material has a large specific surface area and excellent catalytic performance after phosphidation.

[0073] (2) The test system is a three-electrode system: Using the ZIF-type metal-organic framework material prepared in Comparative Example 3, the CoZnP prepared in Example 1, the CoZnP prepared in Example 2, and the CoZnP prepared in Example 3 as the working electrode, a carbon electrode as the auxiliary electrode, a Hg / HgO electrode as the reference electrode, and a 0.5 mol / L NaOH solution as the electrolyte, an electrochemical impedance spectroscopy test was carried out, and an impedance spectrum was plotted, as Figure 6As shown in the figure. Among them, the ZIF-type metal-organic framework material prepared in Comparative Example 3 is labeled as ZIF in the figure, the CoZnP prepared in Example 1 is labeled as ZIF-0.5P in the figure, the CoZnP prepared in Example 2 is labeled as ZIF-P in the figure, and the CoZnP prepared in Example 3 is labeled as ZIF-1.5P in the figure.

[0074] Figure 6 It can be seen that the impedance radii of Examples 1 to 3 are all better than that of Comparative Example 3, and the impedance radius of Example 2 is the best. This shows that when the amount of phosphide used is 1 g, the prepared CoZnP has the best impedance radius, the highest charge transfer rate, and the best electrochemical performance.

[0075] Combined with the above analysis, it can be known that the prepared transition metal phosphide electrode material of the present invention has excellent electrochemical performance when used in the catalytic hydrogen evolution process, and when the mass of the phosphide used is 1 g, the catalytic hydrogen evolution efficiency is the highest.

[0076] In summary, the above test results show that the preparation method of the transition metal phosphide electrode material provided by the present invention can successfully prepare the transition metal phosphide electrode material, and the prepared transition metal phosphide electrode material of the present invention has high catalytic hydrogen evolution performance, thus indicating that the present invention can solve the technical problem of poor catalytic hydrogen evolution performance of existing transition metal compounds to meet the demand for hydrogen production by electrolytic water reaction.

[0077] The above-described are only the preferred embodiments of the present invention, and the above specific embodiments are not limitations on the present invention. Within the scope of the technical idea of the present invention, various deformations and modifications can occur. Any retouching, modification, or equivalent replacement made by those of ordinary skill in the art according to the above description belongs to the scope protected by the present invention.

Claims

1. A method for preparing a transition metal phosphide electrode material, characterized in that: The following steps are involved: Under room temperature conditions, a precursor having a two-dimensional nanosheet array structure is coordinated with dimethylimidazole to form a ZIF-type metal-organic framework material; The ZIF metal organic framework material and the hypophosphite are calcined to form an array of phosphated two-dimensional nanosheet structures to prepare a transition metal phosphide electrode material; The precursor is prepared by reacting a mixed solution of transition metal salt, ammonium fluoride and urea on a foamed nickel substrate; the transition metal in the transition metal salt is at least two of Fe, Co, Ni, Cu, Zn, Mo and W.

2. The method for preparing a transition metal phosphide electrode material according to claim 1, characterized in that: The molar ratio of the precursor to the dimethylimidazole is 1:35-60.

3. The method for preparing the transition metal phosphide electrode material according to claim 1, characterized in that: The molar ratio of the ZIF type metal organic framework material to the hypophosphite is 1:

10.

4. The method for preparing a transition metal phosphide electrode material according to claim 1, characterized in that: The calcination process comprises the following steps: Raise the temperature to 250℃~350℃ and keep warm for 1h~3h.

5. The method for preparing a transition metal phosphide electrode material according to claim 1, characterized in that: The steps of preparing the precursor include: Dispersing at least two transition metal salts, ammonium fluoride and urea in a solvent to prepare a mixed solution; Immersing the nickel foam substrate in the mixed solution, heating and reacting to form a two-dimensional nanosheet array structure, thereby obtaining a precursor; Wherein, the heating temperature is 90°C to 130°C, and the heating time is 4h to 8h.

6. The method for preparing a transition metal phosphide electrode material according to claim 5, characterized in that: The molar ratio of the at least two transition metal salts, the ammonium fluoride and the urea is 3-4:1:25-26.

7. The method for preparing a transition metal phosphide electrode material according to claim 5, characterized in that: The solvent is at least one of deionized water, methanol and ethanol.

8. The method for preparing a transition metal phosphide electrode material according to claim 5, characterized in that: The foam nickel substrate is prepared by firstly subjecting the foam nickel to ultrasonic acid washing and then to ultrasonic water washing.

9. The method for preparing a transition metal phosphide electrode material according to claim 1, characterized in that: When the precursor is coordinated with dimethylimidazole to carry out contact reaction, the standing time is 2h to 4h.

10. A transition metal phosphide electrode material, characterized in that: The electrode material is prepared by the method for preparing the transition metal phosphide electrode material as described in any one of claims 1 to 9.

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