A non-precious metal ternary heterogeneous structure catalyst and its preparation method and application

Abstract

The application discloses a non-noble metal ternary heterostructure catalyst and a preparation method and application thereof. A dimethyl imidazole solution is slowly added into a Mo salt solution to obtain a suspension liquid containing a Mo metal organic framework Mo-MOF; the obtained solid precipitate is vacuum dried to obtain the Mo-MOF containing the Mo metal organic framework; Ni salt, Fe salt and the Mo-MOF are added into an anhydrous ethanol solution to perform ion exchange to obtain a precursor; the precursor is calcined in a protective atmosphere to obtain an interface-rich ternary heterostructure Ni3Mo3N@Fe3Mo3C / Mo2C catalyst. The catalyst can be applied in hydrogen production by electrolysis of water, promotes an oxygen evolution reaction of alkaline electrolysis of water, and has excellent alkaline oxygen evolution catalytic activity and catalytic stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrocatalysis, and in particular to a non-noble metal ternary heterostructure Ni3Mo3N@Fe3Mo3C / Mo2C catalyst as well as a preparation method and application thereof. BACKGROUND

[0002] With the consumption of fossil energy and the increase of environmental pressure, exploring efficient, clean and renewable energy has become one of the most important challenges today. Wind and solar energy are important sustainable energy, however, they have the characteristics of intermittency and unpredictability, so it is difficult to store continuously. The electrochemical water splitting technology is considered as an efficient, environmentally friendly wind and solar energy conversion and storage technology. 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 barrier of the two reaction processes and accelerate the kinetic reaction. Among the two half-reactions, the oxygen evolution reaction at the anode involves four electron transfer, which is the main rate-limiting step of hydrogen production by water electrolysis, so the development of high-activity oxygen evolution electrocatalysts is crucial to the development of water electrolysis technology.

[0003] An ideal electrocatalyst must have high activity and excellent stability. At present, noble metal Ir / Ru-based materials are the benchmark electrocatalysts for oxygen evolution reaction. However, their scarcity and high cost hinder their large-scale application. In order to replace noble metals and meet the challenges of future large-scale application, researchers are exploring abundant and economical non-noble metal electrocatalysts, such as nickel, cobalt and iron-based catalysts. Since the oxygen evolution reaction is a four-electron reaction, non-noble metal electrocatalysts can obtain a lower overpotential when the active sites have a suitable adsorption energy for oxygen intermediates (*OH, *O and *OOH). How to improve the catalytic activity and stability of non-noble metal catalysts is the focus of non-noble metal catalyst research. One method is to develop efficient non-noble metal-based electrocatalysts by increasing the number of catalytically active sites or improving the intrinsic reactivity. In addition, the construction of heterojunctions can adjust the electronic structure of the material, enhance the intrinsic activity of the surface or edge sites of the material, and promote the separation of reaction intermediates at different interfaces. SUMMARY

[0004] In order to solve the above-mentioned defects in the prior art, the purpose of the present application is to provide a non-noble metal ternary heterostructure catalyst as well as a preparation method and application thereof. The purpose is to provide a non-noble metal ternary heterojunction catalytic material, which has excellent water electrolysis oxygen evolution performance and a lower oxygen evolution overpotential than commercial RuO2; the catalyst is a non-noble metal catalyst, and the preparation cost is lower.

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

[0006] In one aspect of the present application, a preparation method of a non-noble metal ternary heterostructure catalyst is provided, comprising the following steps:

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

[0008] b. Slowly add the dimethylimidazole solution to the Mo salt solution at room temperature according to the molar ratio of dimethylimidazole to Mo element being (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, vacuum dry the obtained solid to obtain Mo-MOF;

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

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

[0011] As a preferred, the Mo salt is one of MoCl5 or MoCl3.

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

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

[0014] As a preferred, in step a, the volume ratio of anhydrous ethanol to methanol is 1:1.

[0015] As a preferred, in step b, the suspension is centrifuged to remove the supernatant after standing for 10-15 hours, washed with anhydrous ethanol and centrifuged for 3-4 times, and the obtained solid is vacuum dried for 2-5 hours.

[0016] In step c, ion exchange for 5-8 hours, centrifugal washing for 2-3 times, and vacuum drying at 50-60°C for 2-5 hours.

[0017] As a preferred, 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 DEG C, the temperature rising speed is 3-5 DEG C / min, and the holding time is 3-6 hours.

[0019] In another aspect of the present application, a non-noble metal ternary heterojunction catalyst prepared by the method is provided.

[0020] The present application has the following beneficial effects due to the above technical solutions:

[0021] 1. The ion exchange reaction is carried out on the basis of the Mo-MOF precursor, so that the elements are uniformly distributed, which facilitates the uniform dispersion of the Ni3Mo3N, Fe3Mo3C and Mo2C components, and is beneficial to obtaining the interface-rich heterojunction catalyst and promoting the alkaline electrolytic water oxygen evolution reaction for the formed Ni3Mo3N@Fe3Mo3C / Mo2C heterojunction catalyst.

[0022] 2. The ternary heterojunction has a higher band overlap degree than the binary heterojunction, which is beneficial to reducing the overpotential, accelerating the reaction kinetics and stabilizing the chemical properties.

[0023] 3. The ternary heterojunction Ni3Mo3N@Fe3Mo3C / Mo2C catalyst provided by the present application can efficiently perform the electrolytic water oxygen evolution reaction under alkaline conditions, and only needs 118.2 mV overpotential at 10 mA cm -2 .

[0024] 4. Compared with the commonly used noble metal oxide RuO2, the raw material cost of the present application is lower, and the catalytic performance is better than that of the noble metal RuO2 catalyst, and has higher stability.

[0025] 5. The preparation method of the non-noble metal heterojunction catalyst provided by the present application has the advantages of easy-to-obtain raw materials, simple process, simple required equipment, controllable and adjustable structure components, and is beneficial to mass production. DETAILED DESCRIPTION

[0026] The accompanying drawings, which are included to provide a further understanding of the present application and constitute a part of this application, do not constitute improper limitations to the present application, and in the drawings:

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

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

[0029] Figure 3is a scanning electron microscope image of the Fe3Mo3C@Mo2C sample of Comparative Example 2;

[0030] Figure 4 is a graph of electrochemical polarization curves 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 is a graph of overpotential comparison of the ternary heterojunction Ni3Mo3N@Fe3Mo3C / Mo2C catalyst and the sample Fe3Mo3C@Mo2C in Comparative Example 1 at different currents;

[0032] Figure 6 is an impedance diagram of the oxygen evolution reaction 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 is a graph of electrochemical polarization curve comparison of the ternary heterojunction Ni3Mo3N@Fe3Mo3C / Mo2C catalyst and a commercial RuO2 catalyst;

[0034] Figure 8 is a stability test graph of the oxygen evolution reaction of the ternary heterojunction Ni3Mo3N@Fe3Mo3C / Mo2C catalyst in 1M KOH solution. DETAILED DESCRIPTION

[0035] The present application will be described in detail below with reference to the accompanying drawings and specific examples, which are used to explain the present application but not to limit the present application.

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

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

[0038] Step 2: At room temperature, the dimethylimidazole solution is slowly added dropwise to a Mo salt (one of MoCl5 and MoCl3) solution according to a molar ratio of dimethylimidazole to Mo element of (9-11): (0.9-1.1), and the mixture is stirred thoroughly to obtain a suspension containing a Mo metal-organic framework Mo-MOF; the suspension is then allowed to stand for 10-15 hours, and the supernatant is removed by centrifugation, and the suspension is washed with anhydrous ethanol and centrifuged 3-4 times. Finally, the resulting solid is placed in a vacuum drying oven and dried 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 ratio of the sum of the mass of Ni element and Fe element to the mass of 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, FeCl3) and Mo-MOF obtained in step 2, place them in a beaker, add anhydrous ethanol solution, stir evenly, perform ion exchange for 5-8 hours, 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 tube furnace, introduce a mixed gas of 5% hydrogen and 95% argon, heat it to 650-750°C at a heating rate of 3-5°C / min, and calcine it. Keep it warm 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 is further described below through different embodiments.

[0042] Example 1

[0043] (1) dissolving dimethylimidazole in a mixed solution of anhydrous ethanol and methanol in a volume ratio of 1:1 according to a molar ratio of dimethylimidazole to Mo element of 10:1 to obtain a dimethylimidazole solution; dissolving MoCl5 in a mixed solution of anhydrous ethanol and methanol in a volume ratio of 1:1 to obtain a Mo salt solution;

[0044] (2) At room temperature, the dimethylimidazole solution obtained in step (1) was slowly added dropwise to the Mo salt solution, and the mixture was stirred thoroughly to obtain a Mo metal organic framework Mo-MOF; the suspension was then allowed to stand for 12 hours and then centrifuged to remove the supernatant, and the suspension was washed with anhydrous ethanol and centrifuged three times. Finally, the obtained solid was placed in a vacuum drying oven and dried at 60° C. for 3 hours to obtain Mo-MOF;

[0045] (3) According to the molar ratio of Ni element to Fe element being 0.9:1 and the ratio of the sum of the mass of Ni element and Fe element to the mass of Mo-MOF being 0.25:1, Fe(NO3)3 and Mo-MOF are weighed into a beaker, anhydrous ethanol solution is added, stirring is uniformly conducted, ion exchange is conducted for 6 hours, finally washing, centrifugation, vacuum drying at 60℃ for 2 hours to obtain a precursor;

[0046] (4) The precursor obtained in step (3) is placed in a tube furnace, a mixed gas of 5% hydrogen and 95% argon is introduced, the temperature is raised to 700℃ at a temperature rising rate of 3℃ / min, calcination treatment is conducted, the temperature is kept for 3 hours, the temperature is naturally reduced to room temperature, and a ternary heterostructure Ni3Mo3N@Fe3Mo3C / Mo2C catalyst is obtained.

[0047] Figure 1 The XRD pattern of the sample prepared in Example 1 is shown in the figure, the XRD diffraction peak of the Ni3Mo3N@Fe3Mo3C / Mo2C catalyst is matched well with the standard card Ni3Mo3N (PDF #49-1336), Fe3Mo3C (PDF #47-1191), 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 dimethyl imidazole to Mo element being 9:1.1, dimethyl imidazole is dissolved in a mixed solution of anhydrous ethanol and methanol in a volume ratio of 1:1 to obtain a dimethyl imidazole solution; MoCl5 is dissolved in a mixed solution of anhydrous ethanol and methanol in a volume ratio of 1:1 to obtain a Mo salt solution;

[0050] (2) At room temperature, the dimethyl imidazole solution obtained in step (1) is slowly added to the Mo salt solution, stirring is fully conducted to obtain a Mo metal organic framework Mo-MOF suspension; then the suspension is left standing for 10 hours, the supernatant is removed by centrifugation, the obtained solid is washed by anhydrous ethanol and centrifuged for 3 times, finally the obtained solid is placed in a vacuum drying oven and dried at 60℃ 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 ratio of the sum of the mass of Ni element and Fe element to the mass of Mo-MOF being 0.35:1, NiCl2, Fe(NO3)3 and Mo-MOF are weighed into a beaker, anhydrous ethanol solution is added, stirring is uniformly conducted, ion exchange is conducted for 5 hours, finally washing, centrifugation, vacuum drying at 60℃ for 3 hours to obtain a precursor;

[0052] (4) The precursor obtained in step (3) is placed in a tube furnace, a mixed gas of 5% hydrogen and 95% argon is introduced, and the temperature is raised to 650°C at a temperature rising rate of 4°C / min for calcination treatment, and the temperature is kept for 5 hours. When the temperature naturally decreases to room temperature, a ternary heterogeneous structure Ni3Mo3N@Fe3Mo3C / Mo2C catalyst is obtained.

[0053] Example 3

[0054] (1) According to the molar ratio of dimethyl imidazole to Mo element of 11:1, dimethyl imidazole is dissolved in a mixed solution of anhydrous ethanol and methanol in a volume ratio of 1:1 to obtain a dimethyl imidazole solution; MoCl5 is dissolved in a mixed solution of anhydrous ethanol and methanol in a volume ratio of 1:1 to obtain a Mo salt solution;

[0055] (2) At room temperature, the dimethyl imidazole solution obtained in step (1) is slowly added to the Mo salt solution, and a Mo metal organic framework Mo-MOF suspension is obtained by stirring; then the suspension is left to stand for 15 hours, the supernatant is removed by centrifugation, the centrifugation is washed with anhydrous ethanol 4 times, and finally the obtained solid is placed in a vacuum drying oven at 50°C for 5 hours to obtain Mo-MOF;

[0056] (3) According to the molar ratio of Ni element to Fe element of 1:1 and the mass ratio of the sum of the mass of Ni element and Fe element to the mass of Mo-MOF of 0.14:1, NiCl2, Fe(NO3)3 and Mo-MOF are weighed and placed in a beaker, anhydrous ethanol solution is added, stirring is uniform, ion exchange is carried out for 7 hours, finally washing, centrifugation, vacuum drying at 50°C for 5 hours to obtain a precursor;

[0057] (4) The precursor obtained in step (3) is placed in a tube furnace, a mixed gas of 5% hydrogen and 95% argon is introduced, and the temperature is raised to 650°C at a temperature rising rate of 4°C / min for calcination treatment, and the temperature is kept for 5 hours. When the temperature naturally decreases to room temperature, a ternary heterogeneous structure Ni3Mo3N@Fe3Mo3C / Mo2C catalyst is obtained.

[0058] Example 4

[0059] (1) According to the molar ratio of dimethyl imidazole to Mo element of 11:1, dimethyl imidazole is dissolved in a mixed solution of anhydrous ethanol and methanol in a volume ratio of 1:1 to obtain a dimethyl imidazole solution; MoCl5 is dissolved in a mixed solution of anhydrous ethanol and methanol in a volume ratio of 1:1 to obtain a Mo salt solution;

[0060] (2) At room temperature, slowly drop the dimethylimidazole solution obtained in step (1) into the Mo salt solution, fully stir to obtain a suspension containing Mo metal organic framework Mo-MOF; then centrifuge and remove the supernatant after the suspension is left to stand for 12 hours, wash and centrifuge the Mo-MOF with anhydrous ethanol for 4 times, and finally dry the obtained solid in a vacuum drying oven 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 ratio of the sum of the mass of Ni element and Fe element to the mass of Mo-MOF being 0.45:1, weigh Ni(NO3)2, FeCl3 and Mo-MOF into a beaker, add anhydrous ethanol solution, stir uniformly, perform ion exchange for 8 hours, finally wash, centrifuge, and vacuum dry at 55°C for 3 hours to obtain a precursor;

[0062] (4) Place the precursor obtained in step (3) in a tube furnace, pass a mixed gas of 5% hydrogen and 95% argon, heat to 750°C at a heating rate of 5°C / min, perform calcination treatment, keep warm for 4 hours, and wait for the temperature to naturally drop to room temperature to obtain a ternary heterostructure Ni3Mo3N@Fe3Mo3C / Mo2C catalyst.

[0063] Comparative Example 1

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

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

[0066] (2) At room temperature, slowly drop the dimethylimidazole solution obtained in step (1) into the Mo salt solution, fully stir to obtain a suspension containing Mo metal organic framework Mo-MOF; then centrifuge and remove the supernatant after the suspension is left to stand for 12 hours, wash and centrifuge the Mo-MOF with anhydrous ethanol for 3 times, and finally dry the obtained solid in a vacuum drying oven at 60°C for 3 hours to obtain Mo-MOF;

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

[0068] (4) The precursor obtained in step (3) is placed in a tube furnace, and a mixed gas of 5% hydrogen and 95% argon is introduced, and the temperature is raised to 700°C at a temperature rising rate of 3°C / min for calcination treatment, and the temperature is kept for 3 hours, and the temperature is naturally reduced to room temperature, to obtain a ternary heterostructure Fe3Mo3C@Mo2C catalyst.

[0069] Figure 2 and Figure 3 The scanning electron micrographs of the Ni3Mo3N@Fe3Mo3C / Mo2C catalyst and the Fe3Mo3C@Mo2C catalyst in Comparative Example 1, respectively. Compared with Fe3Mo3C@Mo2C, the particle size of Ni3Mo3N@Fe3Mo3C / Mo2C is smaller, indicating that the introduction of Ni source is beneficial to inhibit the aggregation phenomenon of the material in the synthesis, to form a catalyst with smaller particle size, and to expose more catalytically active sites.

[0070] Comparative Example 2

[0071] The present comparative example provides a Mo2C catalyst, which is prepared as follows:

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

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

[0074] (3) The same amount of Mo-MOF as in Example 1 is weighed into a beaker, anhydrous ethanol solution is added, and stirring is performed for 6 hours, and finally washing, centrifugation, and vacuum drying at 60°C for 2 hours to obtain a precursor;

[0075] (4) The precursor obtained in step (3) is placed in a tube furnace, and a mixed gas of 5% hydrogen and 95% argon is introduced, and the temperature is raised to 700°C at a temperature rising rate of 3°C / min for calcination treatment, and the temperature is kept for 3 hours, and the temperature is naturally reduced to room temperature, to obtain a ternary heterostructure Fe3Mo3C@Mo2C catalyst.

[0076] Figure 4The linear voltammetric sweep curves of Ni3Mo3N@Fe3Mo3C / Mo2C, Comparative Example 1 sample Fe3Mo3C@Mo2C and Comparative Example 2 sample Mo2C are shown. As can be seen from the figure, the catalytic activity of Ni3Mo3N@Fe3Mo3C / Mo2C is better than that of Comparative Example 1 sample Fe3Mo3C@Mo2C and Comparative Example 2 sample Mo2C, indicating that the ternary heterogeneous interface constructed by the introduction of Ni element during the synthesis process significantly promotes the electrocatalytic oxygen evolution reaction activity. At the same time, Figure 5 As shown in Figure 2, compared with the sample Fe3Mo3C@Mo2C in proportion 1, the ternary heterostructure Ni3Mo3N@Fe3Mo3C / Mo2C catalyst requires a lower overpotential to reach 10, 50, and 100 mA cm -2 When the overpotential is 10 mA cm -2 When , the overpotential of Ni3Mo3N@Fe3Mo3C / Mo2C is 118.2mV, which shows excellent electrocatalytic oxygen evolution performance.

[0077] Figure 6 The electrochemical impedance spectroscopy test results for the Ni3Mo3N@Fe3Mo3C / Mo2C catalysts, the Fe3Mo3C@Mo2C sample from Comparative Example 1, and the Mo2C sample from Comparative Example 2 are shown. As can be seen from the figure, the impedance spectrum of the ternary heterojunction Ni3Mo3N@Fe3Mo3C / Mo2C catalyst exhibits a smaller semicircle, meaning it has a smaller impedance value than the Fe3Mo3C@Mo2C sample from Comparative Example 1 and the Mo2C sample from Comparative Example 2. This indicates that the charge transfer rate between the ternary heterojunction Ni3Mo3N@Fe3Mo3C / Mo2C catalyst and the solution during the oxygen evolution electrocatalytic reaction is faster, which is conducive to achieving higher electrocatalytic oxygen evolution activity.

[0078] Application examples:

[0079] An application of Ni3Mo3N@Fe3Mo3C / Mo2C prepared by the preparation method described above in an electrocatalytic alkaline oxygen evolution reaction comprises:

[0080] 5 mg of catalyst (Ni3Mo3N@Fe3Mo3C / Mo2C, Fe3Mo3C@Mo2C, Mo2C and RuO2) and 1 mg of Ketjen black were ultrasonically dispersed in a mixed solution of 50 μL Nafion and 1 mL of ethanol for 30 minutes to obtain a catalyst ink. The catalyst ink was dropped into a 1×1.5 cm 2 The samples were vacuum dried on carbon cloth for 1 hour.

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

[0082] Figure 7 The linear voltammetric sweep curve test results of Ni3Mo3N@Fe3Mo3C / Mo2C and commercial RuO2 catalysts are shown in the figure. As can be seen from the figure, the ternary heterojunction Ni3Mo3N@Fe3Mo3C / Mo2C catalyst has better / similar oxygen evolution catalytic activity than commercial RuO2. Figure 8 It can be seen 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-mentioned embodiments. On the basis of the technical solutions disclosed in the present invention, those skilled in the art can make some substitutions and modifications to some of the technical features therein according to the disclosed technical content without creative labor, and these substitutions and modifications are all within the protection scope of the present invention.

Claims

1. A method for preparing a non-precious metal ternary heterogeneous structure catalyst, characterized in that: The following steps are involved: a. dissolving dimethylimidazole in a mixed solution of anhydrous ethanol and methanol to obtain a dimethylimidazole solution; dissolving Mo salt in a mixed solution of anhydrous ethanol and methanol to obtain a Mo salt solution; b. Slowly add a dimethylimidazole solution dropwise to a Mo salt solution at room temperature in a molar ratio of dimethylimidazole to Mo element of (9-11):(0.9-1.1), stirring, to obtain a suspension containing a Mo metal-organic framework (Mo-MOF); allow the suspension to stand, remove the supernatant, centrifuge and wash the precipitate, and vacuum dry the resulting solid to obtain the Mo-MOF; c. Add Ni salt, Fe salt, and Mo-MOF to an anhydrous ethanol solution at a molar ratio of Ni to Fe of (0.9-1):(0.9-1) and a mass ratio of the sum of Ni and Fe to Mo-MOF of (0.14-0.45):1, stir to perform ion exchange, wash, centrifuge, and vacuum dry to obtain a precursor; d. The precursor was calcined under a protective atmosphere and allowed to cool naturally to room temperature to obtain a ternary heterostructured Ni3Mo3N@Fe3Mo3C / Mo2C catalyst.

2. The method for preparing the non-noble metal ternary heterogeneous structure catalyst according to claim 1, characterized in that: The molybdenum salt is one of MoCl5 or MoCl3.

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

4. The method for preparing a non-noble metal ternary heterogeneous structure catalyst according to claim 1, characterized in that: The Fe salt is one of Fe(NO3)3 or FeCl3.

5. The method for preparing the non-noble metal ternary heterogeneous structure catalyst according to claim 1, characterized in that: In step a, the volume ratio of anhydrous ethanol to methanol is 1:

1.

6. The method for preparing a non-noble metal ternary heterogeneous structure catalyst according to claim 1, characterized in that: In step b, the suspension is allowed to stand for 10-15 hours, the supernatant is removed by centrifugation, and the suspension is washed with anhydrous ethanol and centrifuged 3-4 times, and the resulting solid is vacuum dried for 2-5 hours; In step c, the ion exchange is performed for 5-8 hours, the product is centrifuged and washed 2-3 times, and vacuum dried at 50-60° C. for 2-5 hours.

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

8. The method for preparing a non-precious metal ternary heterogeneous structure catalyst according to claim 1, wherein: In step d, the calcination temperature is 650-750 o C, heating rate is 3-5 o C / min, and the holding time is 3-6 hours.

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

10. Use of the non-noble metal ternary heterostructure catalyst as claimed in claim 9 in hydrogen production by water electrolysis.

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