Non-noble metal ternary heterostructure catalyst as well as preparation method and application thereof

Abstract

The invention discloses a non-noble metal ternary heterostructure catalyst and a preparation method and application thereof, and the preparation method comprises the following steps: slowly dropwise adding a dimethylimidazole solution into a Mo salt solution to obtain a suspension containing a Mo metal organic framework Mo-MOF; carrying out standing, and carrying out vacuum drying on the obtained solid precipitate to obtain Mo-MOF containing the Mo metal organic framework; ni salt, Fe salt and Mo-MOF are added into an absolute ethyl alcohol solution for ion exchange, and a precursor is obtained; and calcining the precursor in a protective atmosphere to obtain the ternary heterostructure Ni3Mo3N-coated Fe3Mo3C / Mo2C catalyst with abundant interfaces. The catalyst can be applied to hydrogen production through water electrolysis, can promote an alkaline water electrolysis oxygen evolution reaction, and has excellent alkaline oxygen evolution catalytic activity and catalytic stability.

Description

Technical Field

[0001] The present invention relates to the field of electrocatalytic technology, and particularly relates to a non-precious metal ternary heterostructure Ni3Mo3N@Fe3Mo3C / Mo2C catalyst, a preparation method thereof, and an application thereof. Background Art

[0002] With the consumption of fossil energy and the increasing environmental pressure, exploring efficient, clean, and renewable energy has become one of the most important challenges today. Wind energy and solar energy are important sustainable energy sources. However, due to their intermittent and unpredictable characteristics, it is difficult to store them continuously. The electrochemical water splitting technology is considered to be an efficient and environmentally friendly technology for wind energy and solar energy conversion and storage. The electrochemical water splitting process involves two half-reactions: the hydrogen evolution reaction at the cathode and the oxygen evolution reaction at the anode. However, due to the slow kinetics of the two electrode reactions, the practical application of water electrolysis is limited. Therefore, efficient electrocatalysts are needed to overcome the high reaction barriers of the two reaction processes and accelerate the kinetic reactions. Among these two half-reactions, the oxygen evolution reaction at the anode involves four-electron transfer and is the main rate-limiting step in hydrogen production by water electrolysis. Therefore, the development of highly active oxygen evolution electrocatalysts is crucial for the development of water electrolysis technology.

[0003] Ideal electrocatalysts must have high activity and excellent stability. Currently, noble metal Ir / Ru-based materials are the benchmark electrocatalysts for the oxygen evolution reaction. However, their scarcity and high cost hinder their large-scale application. To replace noble metals and meet the challenges of future large-scale applications, researchers are constantly exploring abundant and economical non-precious metal electrocatalysts, such as nickel, cobalt, and iron-based catalysts. Since the oxygen evolution reaction is a four-electron reaction, non-precious metal electrocatalysts can obtain a lower overpotential when they have a suitable adsorption energy for oxygen intermediates (*OH, *O, and *OOH) at the active sites. How to improve the catalytic activity and stability of non-precious metal catalysts is the focus of non-precious metal catalyst research. One method is to develop efficient non-precious metal-based electrocatalysts by increasing the number of catalytic active sites or enhancing the intrinsic reaction activity. In addition, by constructing heterogeneous interfaces, the electronic structure of the material can be adjusted, the intrinsic activity of the surface or edge sites of the material can be enhanced, and the separation of reaction intermediates at different interfaces can be promoted. Summary of the Invention

[0004] To solve the above-mentioned defects in the prior art, the purpose of the present invention is to provide a non-precious metal ternary heterostructure catalyst, a preparation method thereof, and an application thereof. The purpose is to provide a non-precious metal ternary heterojunction catalytic material with excellent oxygen evolution performance for water electrolysis, a lower oxygen evolution overpotential, which is superior to commercial RuO2; this catalyst is a non-precious metal catalyst with a lower preparation cost.

[0005] The present invention is realized by the following technical solutions.

[0006] One aspect of the present invention provides a method for preparing a non-precious metal ternary heterostructure catalyst, comprising the following steps:

[0007] a. Dissolve dimethylimidazole in a mixed solution of absolute ethanol and methanol to obtain a dimethylimidazole solution; dissolve a Mo salt in a mixed solution of absolute ethanol and methanol to obtain a Mo salt solution;

[0008] b. At room temperature, slowly drop the dimethylimidazole solution into the Mo salt solution according to the molar ratio of dimethylimidazole to Mo element of (9-11):(0.9-1.1), stir to obtain a suspension containing Mo metal-organic framework Mo-MOF; let the suspension stand, remove the supernatant, centrifuge and wash the precipitate, and vacuum-dry the obtained solid to obtain Mo-MOF;

[0009] c. According to the molar ratio of Ni element to Fe element of (0.9-1):(0.9-1) and the mass ratio of the sum of the masses of Ni element and Fe element to Mo-MOF of (0.14-0.45):1, add Ni salt, Fe salt and Mo-MOF to an absolute ethanol solution, stir for ion exchange, wash, centrifuge, and vacuum-dry to obtain a precursor;

[0010] d. Calcinate the precursor under a protective atmosphere and naturally cool to room temperature to obtain a ternary heterostructure Ni3Mo3N@Fe3Mo3C / Mo2C catalyst.

[0011] Preferably, the molybdenum salt is one of MoCl5 or MoCl3.

[0012] Preferably, the Ni salt is one of NiCl2, NiCO3, Ni(NO2)2, NiSO4 or Ni(NO3)2.

[0013] Preferably, the Fe salt is one of Fe(NO3)3 or FeCl3.

[0014] Preferably, in step a, the volume ratio of absolute ethanol to methanol is 1:1.

[0015] Preferably, in step b, the suspension stands for 10-15 hours and then the supernatant is removed by centrifugation, washed 3-4 times with absolute ethanol by centrifugation, and the obtained solid is vacuum-dried for 2-5 hours;

[0016] In step c, ion exchange is carried out for 5-8 hours, centrifuged and washed 2-3 times, and vacuum-dried at 50-60 °C for 2-5 hours.

[0017] Preferably, in step d, the protective atmosphere is a mixed gas of 5% hydrogen and 95% argon.

[0018] Preferably, in step d, the calcination temperature is 650 - 750 °C, the heating rate is 3 - 5 °C / min, and the heat preservation time is 3 - 6 hours.

[0019] Another aspect of the present invention provides a non - noble metal ternary heterostructure catalyst prepared by the above - mentioned method.

[0020] Due to the above - mentioned technical solutions adopted by the present invention, it has the following beneficial effects:

[0021] 1. Based on the Mo - MOF precursor adopted by the present invention, an ion - exchange reaction is carried out, enabling the uniform distribution of each element, facilitating the uniform dispersion of Ni3Mo3N, Fe3Mo3C, and Mo2C components. For the formed Ni3Mo3N@Fe3Mo3C / Mo2C heterojunction catalyst, it is beneficial to obtain a heterojunction catalyst with rich interfaces, promoting the oxygen evolution reaction of alkaline water electrolysis.

[0022] 2. The degree of energy - band overlap of the ternary heterojunction constructed by the present invention is more than that of the binary heterojunction, which is conducive to reducing the over - potential, accelerating the reaction kinetics, and stabilizing the chemical properties.

[0023] 3. The ternary heterostructure Ni3Mo3N@Fe3Mo3C / Mo2C catalyst provided by the present invention can carry out efficient oxygen evolution reaction of water electrolysis under alkaline conditions. At 10 mA cm -2 The over - potential only needs 118.2 mV.

[0024] 4. Compared with the commonly used noble - metal oxide RuO2, the raw material cost of the present invention is lower, and its catalytic performance is superior to that of the noble - metal RuO2 catalyst, with high stability.

[0025] 5. The preparation method of the non - noble metal heterostructure catalyst provided by the present invention has easily available raw materials, a simple process, simple required equipment, controllable and adjustable structural components, and is conducive to mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings described herein are used to provide a further understanding of the present invention, form a part of this application, and do not constitute an improper limitation to the present invention. In the drawings:

[0027] Figure 1 is the XRD pattern of the ternary heterojunction Ni3Mo3N@Fe3Mo3C / Mo2C sample and the standard card pattern;

[0028] Figure 2 is the scanning electron microscope photograph of the ternary heterojunction Ni3Mo3N@Fe3Mo3C / Mo2C sample;

[0029] Figure 3It is the scanning electron microscope photograph of the Fe3Mo3C@Mo2C sample in Comparative Example 2;

[0030] Figure 4 It is the electrochemical polarization curve diagram of the ternary heterojunction Ni3Mo3N@Fe3Mo3C / Mo2C catalyst, the sample Fe3Mo3C@Mo2C in Comparative Example 1, and the sample Mo2C in Comparative Example 2;

[0031] Figure 5 It is the overpotential comparison diagram of the ternary heterojunction Ni3Mo3N@Fe3Mo3C / Mo2C catalyst and the sample Fe3Mo3C@Mo2C in Comparative Example 1 at different currents;

[0032] Figure 6 It is the schematic diagram of the oxygen evolution reaction impedance of the ternary heterojunction Ni3Mo3N@Fe3Mo3C / Mo2C catalyst, the sample Fe3Mo3C@Mo2C in Comparative Example 1, and the sample Mo2C in Comparative Example 2;

[0033] Figure 7 It is the comparison diagram of the electrochemical polarization curves of the ternary heterojunction Ni3Mo3N@Fe3Mo3C / Mo2C catalyst and the commercial RuO2 catalyst;

[0034] Figure 8 It is the stability test diagram of the oxygen evolution reaction of the ternary heterojunction Ni3Mo3N@Fe3Mo3C / Mo2C catalyst in 1M KOH solution. Detailed implementation mode

[0035] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. Here, the illustrative embodiments of the present invention and the description are used to explain the present invention, but not to limit the present invention.

[0036] The embodiment of the present invention provides a preparation method of a non-noble metal ternary heterostructure Ni3Mo3N@Fe3Mo3C / Mo2C catalyst, comprising the following steps:

[0037] Step 1, dissolve a certain amount of dimethylimidazole in a mixed solution of anhydrous ethanol and methanol with a volume ratio of 1:1 to obtain a dimethylimidazole solution; dissolve a certain amount of Mo salt (one of MoCl5 and MoCl3) in a mixed solution of anhydrous ethanol and methanol with a volume ratio of 1:1 to obtain a salt solution of Mo;

[0038] Step 2: At room temperature, slowly add the dimethylimidazole solution to the Mo salt (one of MoCl5 and MoCl3) solution according to the molar ratio of dimethylimidazole to Mo element of (9-11):(0.9-1.1), and stir well to obtain a suspension containing Mo metal-organic framework Mo-MOF; then let the suspension stand for 10-15 hours, centrifuge to remove the supernatant, wash and centrifuge 3-4 times with absolute ethanol, and finally place the obtained solid in a vacuum drying oven and dry it at 50-60 °C for 2-5 hours to obtain Mo-MOF;

[0039] Step 3: According to the molar ratio of Ni element to Fe element of (0.9-1):(0.9-1) and the mass ratio of the sum of Ni element and Fe element to Mo-MOF of (0.14-0.45):1, weigh a certain amount of Ni salt (one of NiCl2, NiCO3, Ni(NO2)2, NiSO4 or Ni(NO3)2), Fe salt (one of Fe(NO3)3 and FeCl3) and the Mo-MOF obtained in Step 2, place them in a beaker, add absolute ethanol solution, stir evenly, carry out ion exchange for 5-8 hours, and finally wash, centrifuge, and vacuum dry at 50-60 °C for 2-5 hours to obtain a precursor;

[0040] Step 4: Place the precursor obtained in Step 3 in a tubular furnace, introduce a mixed gas of 5% hydrogen and 95% argon, heat it at a heating rate of 3-5 °C / min to 650-750 °C for calcination treatment, keep the temperature for 3-6 hours, and wait for the temperature to naturally drop to room temperature to obtain a ternary heterostructure Ni3Mo3N@Fe3Mo3C / Mo2C catalyst.

[0041] The present invention will be further illustrated by different embodiments below.

[0042] Example 1

[0043] (1) Dissolve dimethylimidazole in a mixed solution of absolute ethanol and methanol with a volume ratio of 1:1 according to the molar ratio of dimethylimidazole to Mo element of 10:1 to obtain a dimethylimidazole solution; dissolve MoCl5 in a mixed solution of absolute ethanol and methanol with a volume ratio of 1:1 to obtain a salt solution of Mo.

[0044] (2) At room temperature, slowly add the dimethylimidazole solution obtained in step (1) to the Mo salt solution, and stir well to obtain Mo metal-organic framework Mo-MOF; then let the suspension stand for 12 hours, centrifuge to remove the supernatant, wash and centrifuge 3 times with absolute ethanol, and finally place the obtained solid in a vacuum drying oven and dry it at 60 °C for 3 hours to obtain Mo-MOF;

[0045] (3) Weigh Fe(NO3)3 and Mo-MOF into a beaker according to the molar ratio of Ni element to Fe element being 0.9:1 and the mass ratio of the sum of Ni element and Fe element to the mass of Mo-MOF being 0.25:1. Add anhydrous ethanol solution, stir evenly, conduct ion exchange for 6 hours, and finally wash, centrifuge, and vacuum dry at 60 °C for 2 hours to obtain the precursor;

[0046] (4) Place the precursor obtained in step (3) into a tubular furnace, introduce a mixed gas of 5% hydrogen and 95% argon, heat it up to 700 °C at a heating rate of 3 °C / min for calcination treatment, keep the temperature for 3 hours, and wait for the temperature to naturally drop to room temperature to obtain the ternary heterostructure Ni3Mo3N@Fe3Mo3C / Mo2C catalyst.

[0047] Figure 1 XRD pattern of the sample prepared in Example 1. The XRD diffraction peaks of the Ni3Mo3N@Fe3Mo3C / Mo2C catalyst match well with the standard cards Ni3Mo3N (PDF#49-1336), Fe3Mo3C (PDF#47-1191), and Mo2C (PDF#35-0787), indicating the successful preparation of the Ni3Mo3N@Fe3Mo3C / Mo2C catalyst.

[0048] Example 2

[0049] (1) According to the molar ratio of dimethylimidazole to Mo element being 9:1.1, dissolve dimethylimidazole in a mixed solution of anhydrous ethanol and methanol with a volume ratio of 1:1 to obtain a dimethylimidazole solution; dissolve MoCl5 in a mixed solution of anhydrous ethanol and methanol with a volume ratio of 1:1 to obtain a salt solution of Mo;

[0050] (2) At room temperature, slowly drop the dimethylimidazole solution obtained in step (1) into the salt solution of Mo, stir well to obtain a suspension containing Mo metal-organic framework Mo-MOF; then let the suspension stand for 10 hours and centrifuge to remove the supernatant, wash and centrifuge with anhydrous ethanol 3 times, and finally place the obtained solid in a vacuum drying oven and dry at 60 °C for 3 hours to obtain Mo-MOF;

[0051] (3) According to the molar ratio of Ni element to Fe element being 1:0.9 and the mass ratio of the sum of Ni element and Fe element to the mass of Mo-MOF being 0.35:1, weigh NiCl2, Fe(NO3)3, and Mo-MOF into a beaker, add anhydrous ethanol solution, stir evenly, conduct ion exchange for 5 hours, and finally wash, centrifuge, and vacuum dry at 60 °C for 3 hours to obtain the precursor;

[0052] (4) Place the precursor obtained in step (3) in a tubular furnace, introduce a mixed gas of 5% hydrogen and 95% argon, heat it at a heating rate of 4 °C / min to 650 °C for calcination, hold for 5 hours, and wait for the temperature to naturally drop to room temperature to obtain the ternary heterostructure Ni3Mo3N@Fe3Mo3C / Mo2C catalyst.

[0053] Example 3

[0054] (1) According to the molar ratio of dimethylimidazole to Mo element being 11:1, dissolve dimethylimidazole in a mixed solution of anhydrous ethanol and methanol with a volume ratio of 1:1 to obtain a dimethylimidazole solution; dissolve MoCl5 in a mixed solution of anhydrous ethanol and methanol with a volume ratio of 1:1 to obtain a salt solution of Mo.

[0055] (2) At room temperature, slowly drop the dimethylimidazole solution obtained in step (1) into the salt solution of Mo, stir well to obtain a suspension containing Mo metal-organic framework Mo-MOF; then let the suspension stand for 15 hours and centrifuge to remove the supernatant, wash it 4 times with anhydrous ethanol by centrifugation, and finally place the obtained solid in a vacuum drying oven and dry it at 50 °C for 5 hours to obtain Mo-MOF.

[0056] (3) According to the molar ratio of Ni element to Fe element being 1:1 and the mass ratio of the sum of Ni element and Fe element to Mo-MOF being 0.14:1, weigh NiCl2, Fe(NO3)3 and Mo-MOF and place them in a beaker, add an anhydrous ethanol solution, stir evenly, carry out ion exchange for 7 hours, and finally wash, centrifuge, and vacuum dry at 50 °C for 5 hours to obtain a precursor.

[0057] (4) Place the precursor obtained in step (3) in a tubular furnace, introduce a mixed gas of 5% hydrogen and 95% argon, heat it at a heating rate of 5 °C / min to 670 °C for calcination, hold for 4 hours, and wait for the temperature to naturally drop to room temperature to obtain the ternary heterostructure Ni3Mo3N@Fe3Mo3C / Mo2C catalyst.

[0058] Example 4

[0059] (1) According to the molar ratio of dimethylimidazole to Mo element being 10:0.9, dissolve dimethylimidazole in a mixed solution of anhydrous ethanol and methanol with a volume ratio of 1:1 to obtain a dimethylimidazole solution; dissolve MoCl5 in a mixed solution of anhydrous ethanol and methanol with a volume ratio of 1:1 to obtain a salt solution of Mo.

[0060] (2) At room temperature, the dimethylimidazole solution obtained in step (1) was slowly added dropwise to the salt solution of Mo, and stirred well to obtain a suspension containing the Mo metal-organic framework Mo-MOF; then the suspension was left standing for 12 hours, centrifuged to remove the supernatant, washed 4 times with anhydrous ethanol by centrifugation, and finally the obtained solid was placed in a vacuum drying oven and dried at 55 °C for 3 hours to obtain Mo-MOF;

[0061] (3) According to the molar ratio of Ni element to Fe element being 0.9:0.9 and the mass ratio of the sum of Ni element and Fe element to the mass of Mo-MOF being 0.45:1, Ni(NO3)2, FeCl3 and Mo-MOF were weighed and placed in a beaker, anhydrous ethanol solution was added, stirred evenly, and ion exchange was carried out for 8 hours. Finally, it was washed, centrifuged, and vacuum dried at 55 °C for 3 hours to obtain the precursor;

[0062] (4) The precursor obtained in step (3) was placed in a tubular furnace, and a mixed gas of 5% hydrogen and 95% argon was introduced, heated to 750 °C at a heating rate of 5 °C / min for calcination treatment, held for 4 hours, and waited for the temperature to naturally drop to room temperature to obtain the ternary heterostructure Ni3Mo3N@Fe3Mo3C / Mo2C catalyst.

[0063] Comparative Example 1

[0064] This comparative example provides a binary Fe3Mo3C@Mo2C heterostructure catalyst, and its preparation process is as follows:

[0065] (1) According to the molar ratio of dimethylimidazole to Mo element being 10:1, dimethylimidazole was dissolved in a mixed solution of anhydrous ethanol and methanol with a volume ratio of 1:1 to obtain a dimethylimidazole solution; MoCl5 was dissolved in a mixed solution of anhydrous ethanol and methanol with a volume ratio of 1:1 to obtain a salt solution of Mo;

[0066] (2) At room temperature, the dimethylimidazole solution obtained in step (1) was slowly added dropwise to the Mo salt solution, and stirred well to obtain the Mo metal-organic framework Mo-MOF; then the suspension was left standing for 12 hours, centrifuged to remove the supernatant, washed 3 times with anhydrous ethanol by centrifugation, and finally the obtained solid was placed in a vacuum drying oven and dried at 60 °C for 3 hours to obtain Mo-MOF;

[0067] (3) Weigh the same amount of Fe(NO3)3 as in Example 1 and Mo-MOF and place them in a beaker, add anhydrous ethanol solution, stir evenly, carry out ion exchange for 6 hours, and finally wash, centrifuge, and vacuum dry at 60 °C for 2 hours to obtain the precursor;

[0068] (4) The precursor obtained in step (3) is placed in a tubular furnace, and a mixed gas of 5% hydrogen and 95% argon is introduced. It is heated to 700 °C at a heating rate of 3 °C / min for calcination treatment, held for 3 hours, and then allowed to cool naturally to room temperature to obtain a ternary heterostructure Fe3Mo3C@Mo2C catalyst.

[0069] Figure 2 and Figure 3 are the scanning electron microscope images of the Ni3Mo3N@Fe3Mo3C / Mo2C catalyst and the Fe3Mo3C@Mo2C catalyst in Comparative Example 1, respectively. Compared with Fe3Mo3C@Mo2C, Ni3Mo3N@Fe3Mo3C / Mo2C has a smaller particle size, indicating that the introduced Ni source is beneficial to inhibiting the agglomeration phenomenon of the material during synthesis, forming a catalyst with a smaller particle size and exposing more catalytic active sites.

[0070] Comparative Example 2

[0071] This comparative example provides a Mo2C catalyst, and its preparation process is as follows:

[0072] (1) According to the molar ratio of 10:1 of dimethylimidazole to Mo element, dimethylimidazole is dissolved in a mixed solution of anhydrous ethanol and methanol with a volume ratio of 1:1 to obtain a dimethylimidazole solution; MoCl5 is dissolved in a mixed solution of anhydrous ethanol and methanol with a volume ratio of 1:1 to obtain a salt solution of Mo.

[0073] (2) At room temperature, the dimethylimidazole solution obtained in step (1) is slowly added dropwise to the Mo salt solution, and stirred thoroughly to obtain a Mo metal-organic framework Mo-MOF; then the suspension is allowed to stand for 12 hours and centrifuged to remove the supernatant, washed with anhydrous ethanol by centrifugation 3 times, and finally the obtained solid is placed in a vacuum drying oven and dried at 60 °C for 3 hours to obtain Mo-MOF.

[0074] (3) Weigh the same amount of Mo-MOF as in Example 1 and place it in a beaker, add an anhydrous ethanol solution, stir evenly, carry out ion exchange for 6 hours, and finally wash, centrifuge, and vacuum dry at 60 °C for 2 hours to obtain a precursor.

[0075] (4) The precursor obtained in step (3) is placed in a tubular furnace, and a mixed gas of 5% hydrogen and 95% argon is introduced. It is heated to 700 °C at a heating rate of 3 °C / min for calcination treatment, held for 3 hours, and then allowed to cool naturally to room temperature to obtain a Mo2C catalyst.

[0076] Figure 4The linear voltammetry scanning curves of Ni3Mo3N@Fe3Mo3C / Mo2C, the sample of Comparative Example 1 Fe3Mo3C@Mo2C, and the sample of Comparative Example 2 Mo2C are shown. It can be seen from the figure that the catalytic activity of Ni3Mo3N@Fe3Mo3C / Mo2C is better than that of the sample of Comparative Example 1 Fe3Mo3C@Mo2C and the sample of Comparative Example 2 Mo2C, indicating that the ternary heterointerfaces constructed during the synthesis process due to the introduction of Ni element significantly promote the electrocatalytic oxygen evolution reaction activity. At the same time, as Figure 5 shown, compared with the sample of Comparative Example 1 Fe3Mo3C@Mo2C, the ternary heterostructure Ni3Mo3N@Fe3Mo3C / Mo2C catalyst requires a lower overpotential to reach the current densities of 10, 50, and 100 mA cm -2 . When the overpotential is 10 mA cm -2 , the overpotential of Ni3Mo3N@Fe3Mo3C / Mo2C is 118.2 mV, showing excellent electrocatalytic oxygen evolution performance.

[0077] Figure 6 Figure

[0078] shows the electrochemical impedance spectroscopy test results of Ni3Mo3N@Fe3Mo3C / Mo2C, the sample of Comparative Example 1 Fe3Mo3C@Mo2C, and the sample of Comparative Example 2 Mo2C catalysts. It can be seen from the figure that the impedance spectrum of the ternary heterojunction Ni3Mo3N@Fe3Mo3C / Mo2C catalyst shows a smaller semicircle, that is, it has a smaller impedance value compared with the sample of Comparative Example 1 Fe3Mo3C@Mo2C and the sample of Comparative Example 2 Mo2C, indicating that the charge transfer rate between the ternary heterojunction Ni3Mo3N@Fe3Mo3C / Mo2C catalyst and the solution is faster during the oxygen evolution electrocatalytic reaction process, which is beneficial to obtaining higher electrocatalytic oxygen evolution activity.

[0078] Application Example:

[0079] The application of Ni3Mo3N@Fe3Mo3C / Mo2C prepared by the preparation method as described above in the electrocatalytic alkaline oxygen evolution reaction, including:

[0080] Ultrasonically disperse 5 mg of the catalyst (Ni3Mo3N@Fe3Mo3C / Mo2C, Fe3Mo3C@Mo2C, Mo2C, and RuO2) and 1 mg of Ketjen black in a mixed solution of 50 μL of Nafion and 1 mL of ethanol for 30 minutes to obtain the catalyst ink, and drop the catalyst ink onto a 1×1.5 cm 2 carbon cloth and dry it in vacuum for 1 hour.

[0081] The electrochemical performance test of the oxygen evolution reaction was carried out using a three-electrode system, and the electrolyte was 1 M KOH solution. The carbon cloth dropped with the catalyst ink was used as the working electrode, the carbon rod was used as the counter electrode, and the saturated calomel electrode was used as the reference electrode. The polarization curve was measured by linear sweep voltammetry, and the sweep rate was set at 5 mV s -1 . The charge transfer rate between the catalyst and the solution was analyzed by electrochemical impedance spectroscopy, and the test frequency of the impedance spectroscopy was 0.1 Hz - 10 5 Hz. The stability of the catalyst was analyzed by the i-t curve.

[0082] Figure 7 Figure shows the linear voltammetry scanning curve test results of Ni3Mo3N@Fe3Mo3C / Mo2C and commercial RuO2 catalysts. It can be seen from the figure that the ternary heterojunction Ni3Mo3N@Fe3Mo3C / Mo2C catalyst has better / equivalent oxygen evolution catalytic activity compared with commercial RuO2. At the same time, it can be seen from Figure 8 that the ternary heterojunction Ni3Mo3N@Fe3Mo3C / Mo2C catalyst exhibits excellent stability, indicating that the catalyst has good commercial application prospects.

[0083] The present invention is not limited to the above embodiments. Based on the technical solutions disclosed in the present invention, those skilled in the art can make some substitutions and deformations of some technical features without creative labor according to the disclosed technical content, and these substitutions and deformations are within the protection scope of the present invention.

Claims

1. A preparation method of a non-precious metal ternary heterostructure catalyst, characterized in that, It includes the following steps: a. Dissolve dimethylimidazole in a mixed solution of absolute ethanol and methanol to obtain a dimethylimidazole solution; dissolve the Mo salt in a mixed solution of absolute ethanol and methanol to obtain a Mo salt solution; b. At room temperature, slowly drop the dimethylimidazole solution into the Mo salt solution according to the molar ratio of dimethylimidazole to Mo element of (9-11):(0.9-1.1), stir to obtain a suspension containing Mo metal-organic framework Mo-MOF; let the suspension stand, remove the supernatant, centrifuge and wash the precipitate, and vacuum-dry the obtained solid to obtain Mo-MOF; c. According to the molar ratio of Ni element to Fe element of (0.9-1):(0.9-1) and the mass ratio of the sum of Ni element and Fe element to the mass of Mo-MOF of (0.14-0.45):1, add Ni salt, Fe salt and Mo-MOF to an absolute ethanol solution, stir for ion exchange, wash, centrifuge, and vacuum-dry to obtain a precursor; d. Calcinate the precursor under a protective atmosphere and naturally cool to room temperature to obtain a ternary heterostructure Ni3Mo3N@Fe3Mo3C / Mo2C catalyst.

2. The preparation method of the non-noble metal ternary heterostructure catalyst according to claim 1, characterized in that, The molybdenum salt is one of MoCl5 or MoCl3.

3. The preparation method of the non-noble metal ternary heterostructure catalyst according to claim 1, characterized in that, The Ni salt is one of NiCl2, NiCO3, Ni(NO2)2, NiSO4 or Ni(NO3)2.

4. The preparation method of the non-noble metal ternary heterostructure catalyst according to claim 1, characterized in that, The Fe salt is one of Fe(NO3)3 or FeCl3.

5. The preparation method of the non-noble metal ternary heterostructure catalyst according to claim 1, wherein, In step a, the volume ratio of absolute ethanol to methanol is 1:

1.

6. The preparation method of the non-noble metal ternary heterostructure catalyst according to claim 1, characterized in that, In step b, the suspension stands for 10-15 hours and then the supernatant is removed by centrifugation, washed 3-4 times with absolute ethanol by centrifugation, and the obtained solid is vacuum-dried for 2-5 hours; In step c, ion exchange is carried out for 5-8 hours, centrifuged and washed 2-3 times, and vacuum-dried at 50-60 °C for 2-5 hours.

7. The preparation method of the non-noble metal ternary heterostructure catalyst according to claim 1, characterized in that, In step d, the protective atmosphere is a mixed gas of 5% hydrogen and 95% argon introduced.

8. The preparation method of the non-noble metal ternary heterostructure catalyst according to claim 1, characterized in that, In step d, the calcination temperature is 650-750 °C, the heating rate is 3-5 °C / min, and the heat preservation time is 3-6 hours.

9. A non-precious metal ternary heterostructure catalyst prepared by the method according to any one of claims 1-8.

10. Application of the non-precious metal ternary heterostructure catalyst according to claim 9 in hydrogen production by electrolysis of water.

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