A nickel-doped nitride catalyst, a preparation method and application thereof

Abstract

The application discloses a kind of nickel doped nitride catalyst and its preparation method and application, Ni, Mo, N are catalyst components in the catalyst, by the shell-shaped nanosheet of 100-200nm thickness is composed.Its preparation method is one-step hydrothermal and tube furnace calcination to obtain Ni / Mo2N, additionally, a kind of nickel doped nitride catalyst doped MgH2 hydrogen storage material is disclosed as the application in the field of hydrogen storage: under argon condition, after Ni / Mo2N is mixed with MgH2, it is carried out positive and negative conversion ball milling.The application of the obtained MgH2-based hydrogen storage material based on Ni / Mo2N as hydrogen storage material, the doping amount of Ni / Mo2N is 6wt%, and initial dehydrogenation temperature is 175 DEG C-186 DEG C;Dehydrogenation amount is 5.4wt%-5.9wt% at 265 DEG C;Hydrogen absorption amount is 3.1wt%-3.6wt% at 75 DEG C;Retention rate is 97-98% after 10 cycles.

Description

Technical Field

[0001] This invention relates to the technical field of hydrogen storage materials in new energy materials, specifically to a nickel-doped nitride catalyst, its preparation method, and its application. Background Technology

[0002] Hydrogen energy is considered a promising renewable energy source due to its high energy density, environmental friendliness, and wide range of applications. Solid-state hydrogen storage is considered more promising than compressed liquid hydrogen storage. Among various hydrogen storage materials, magnesium-based materials stand out due to their high hydrogen storage density, low operating temperature, and high hydrogen storage capacity. However, stable thermodynamics and slow adsorption kinetics limit their practical application. Currently, researchers commonly employ methods such as catalyst doping, alloying, and microstructure control to improve the performance of magnesium-based hydrogen storage materials. These methods can increase the hydrogenation / dehydrogenation reaction rate and reduce the apparent activation energy of hydrogen absorption and desorption.

[0003] In recent years, researchers have improved the hydrogen storage performance of MgH2 through doping modification, nanostructuring, composite system construction, and nanoengineering. Studies have found that the addition of transition metals can weaken Mg-H interactions and prolong Mg-H bonds because hydrogen atoms tend to form covalent bonds with transition metals, while the covalent bonds between 3d transition metals and H atoms are relatively weak. Therefore, transition metals are identified as key catalytically active substances and are widely used to improve the hydrogen adsorption and desorption performance of MgH2 hydrogen storage systems.

[0004] Currently, transition metals and transition metal nitrides can effectively improve the hydrogen storage performance of composite materials as catalysts, with Ni / Mo2N showing excellent hydrogen storage performance as a catalyst. In particular, the in-situ formation of Mg2Ni / Mg2NiH4 promotes the absorption / dissociation of hydrogen atoms, thereby enhancing the hydrogen storage performance of the composite material.

[0005] Existing technology: Tome, Kudzaishe Caren et al. (International Journal of Hydrogen Energy, 2022, DOI: (10.1016 / j.ijhydene.2021.11.102) prepared Ni and ZrO2-doped MgH2 nanocomposites using a high-energy ball milling method, which reduced the initial hydrogen desorption temperature of the composite material to 255.1℃.

[0006] Similarly, Ding et al. (Journal of Magnesium and Alloys, 2023, DOI: 10.1016 / j.jma.2023.07.002) synthesized Ni nanocatalysts and demonstrated that they have excellent catalytic effects on hydrogen storage in MgH2. Using Ni nanoparticle catalysts to catalyze MgH2 can reduce the peak desorption temperature to 142.5℃.

[0007] In summary, each nickel-based compound improves the performance of MgH2.

[0008] Building upon this, Zhang et al. (Journal of Industrial and Engineering Chemistry, 2022, DOI: 10.1016 / j.jiec.2022.11.024) prepared a hydrangea-like composite catalyst composed of NiO and NiMoO4 using a simple hydrothermal method. Then, they ball-milled it with MgH2 under an argon atmosphere to prepare a hydrangea-shaped bimetallic Ni-Mo oxide catalyst composite material. Through the synergistic effect of the two materials, the overall performance of MgH2 was improved. Although this technique reduced the initial temperature of MgH2 to 190℃ through the synergistic effect of Ni and Mo, which is about 170℃ lower than ball-milled MgH2, it still falls short of its ideal performance.

[0009] Therefore, through a reasonable preparation method, the structure of the catalyst was successfully controlled, resulting in a sheet-like structure with a thickness of 100-200 nm. This structure can act as a grinding aid during ball milling, further reducing the initial hydrogen desorption temperature of MgH2 and thus improving the material's performance.

[0010] The above-mentioned works reported the modification or synergistic catalysis of MgH2 by incorporating nickel-based compounds and transition metal Ni and Mo groups to improve its overall performance. However, the hydrogen storage performance of MgH2 as a hydrogen storage material still has shortcomings in practical applications and needs further improvement. Therefore, the following issues still need to be addressed:

[0011] 1. The problem of poor stability of hydrogen storage materials during cycling;

[0012] 2. The problem of low hydrogen release rate during the hydrogen release process of hydrogen storage materials;

[0013] 3. The problem of poor kinetic performance of hydrogen storage materials during hydrogen release. Summary of the Invention

[0014] The purpose of this invention is to provide a nickel-doped transition metal nitride catalyst, its preparation method, and its application.

[0015] Based on the applicant's work and the research and analysis of the above technical solutions, the following conclusions can be drawn: Current research on the preparation methods of transition metals and transition metal nitrides still cannot achieve a significant improvement in the performance of MgH2.

[0016] Therefore, this invention addresses the existing technical problems in hydrogen storage by employing methods with different preparation conditions to achieve the following objectives:

[0017] Ni / Mo2N was obtained by doping Ni into Mo2N. Subsequently, MgH2 composite material was prepared by grinding MgH2 with 6 wt% catalyst using a planetary mill under Ar atmosphere. Ni / Mo2N effectively improved the hydrogen absorption and desorption performance of MgH2.

[0018] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0019] Ni-doped transition metal nitride Mo2N is used as a catalyst. The preparation process is simple, with Ni, Mo and N as the main components of the catalyst. Ni / Mo2N was obtained through a simple one-step hydrothermal and calcination technique.

[0020] The Ni / Mo2N catalyst was synthesized by hydrothermal and tubular furnace calcination. Its microstructure is a plate-like shell, which makes the ball milling effect more ideal and helps the uniform distribution of Ni / Mo2N on the MgH2 matrix.

[0021] The substrate materials of the catalyst are nickel acetate tetrahydrate, ammonium molybdate tetrahydrate, polyvinylpyrrolidone and urea.

[0022] The preparation method of Ni-doped transition metal nitride Mo2N catalyst includes the following steps:

[0023] Step 1) Preparation of Ni / Mo2N: A certain amount of Ni(CH3COO)2·4H2O and (NH4)6Mo7O are prepared. 24 • Disperse 4H₂O sequentially in deionized water and stir until completely dissolved. Then, slowly add polyvinylpyrrolidone dropwise into the mixture while stirring continuously. After complete dissolution, transfer the solution to an autoclave and maintain it at that temperature for a period of time. After naturally cooling to room temperature, collect the hydrothermal sample deposit.

[0024] Step 2): Wash several times with deionized water and anhydrous ethanol, collect the precipitate after centrifugation, and then dry it under vacuum. Subsequently, place the dried powder and urea into quartz crucibles and transfer them to a tube furnace, where they are calcined for a period of time under a flowing argon gas flow to obtain Ni / Mo2N.

[0025] Preferably, in step 1), Ni(CH3COO)2·4H2O (3 mmol) and (NH4)6Mo7O24 The ingredients are: 4H2O (0.43 mmol), H2O (80 mL), polyvinylpyrrolidone (2.2 mmol), and urea (30 mmol). The stirring conditions in step 1 are: stirring for 15-30 minutes; the order of adding the drugs in step 1) is: adding them slowly and sequentially; the hydrothermal reaction conditions in step 1) are: holding at 180℃ for 15 hours; the washing and drying conditions in step 2) are: washing with deionized water and centrifuging 3-5 times at a speed of 5000-6000 r / min for 3-5 minutes, followed by drying at 60-100℃ for 12 hours; and the calcination conditions in step 2) are: calcining at 500℃ for 2-3 hours.

[0026] This invention also provides a hydrogen storage material doped with MgH2 by a nickel-doped nitride catalyst for application in the field of hydrogen storage. The prepared Ni / Mo2N and MgH2 are mixed in a certain mass ratio and then ball-milled under certain conditions to obtain the Ni / Mo2N-doped MgH2 hydrogen storage material.

[0027] When the doping amount of the catalyst is 2wt%-6wt%, the initial hydrogen release temperature of the system drops to 175℃-186℃, and the hydrogen release amount reaches 6.1wt%-6.9wt%. During isothermal hydrogen release, the system can completely release hydrogen at 325℃, and the hydrogen release amount reaches 6.3wt%-6.9wt% within 6 minutes. During isothermal hydrogen absorption, the system can still absorb 5.0wt%-5.3wt% of hydrogen within 30 minutes, even at temperatures as low as 100℃.

[0028] Preferably, the mass fraction of Ni / Mo2N is 2-6 wt%, and the ball milling conditions are: argon as the protective atmosphere, ball-to-material ratio of 40:1, ball milling speed of 400-450 r / min, and ball milling time of 10-12 h.

[0029] The catalyst obtained in this invention is a nickel-doped transition metal nitride Ni / Mo2N. Its beneficial technical effects, as demonstrated by testing, are as follows:

[0030] Scanning electron microscopy (SEM) analysis revealed that the Ni-doped transition metal nitride Mo2N catalyst exhibits a shell-like structure.

[0031] TPD analysis of Ni-doped transition metal nitride Mo2N showed that when the catalyst doping amount was 6 wt%, the initial hydrogen desorption temperature of the system dropped to 192-186 °C, and the hydrogen desorption amount reached 6.6-6.9 wt%.

[0032] Pressure-composition-temperature (PCT) analysis of the Ni-doped transition metal nitride Mo2N catalyst revealed that: during isothermal hydrogen release, the system can completely release hydrogen at 325℃, with a hydrogen release rate of 6.7-6.9 wt% within 10 min; during isothermal hydrogen absorption, the system can still absorb 4.5-5.1 wt% of hydrogen within 50 min, even at temperatures as low as 75℃.

[0033] Therefore, the Ni-doped transition metal nitride Mo2N catalyst of the present invention has the following advantages over the prior art:

[0034] 1) The in-situ formation of Mg2Ni / Mg2NiH4 enhances the adsorption performance of MgH2.

[0035] 2) The Ni / Mo2N catalyst synthesized by the method of the present invention has an initial hydrogen desorption temperature of 186°C after ball milling with MgH2, which is lower than the value reported in the above literature.

[0036] Therefore, compared with the prior art, the present invention has better hydrogen storage performance and has broad application prospects in the field of hydrogen storage. Attached Figure Description

[0037] Figure 1 The image shows the XRD pattern of the Ni / Mo2N catalyst material prepared in Example 1.

[0038] Figure 2 Scanning electron microscope image of the Ni / Mo2N catalyst material prepared in Example 1;

[0039] Figure 3 TPD curves of Ni / Mo2N-MgH2 composite material with different doping amounts prepared in Example 1.

[0040] Figure 4 The graph shows the isothermal hydrogen desorption performance of the Ni / Mo2N-MgH2 composite material prepared in Example 1 at different temperatures.

[0041] Figure 5 The graph shows the isothermal hydrogen absorption performance of the Ni / Mo2N-MgH2 composite material prepared in Example 1 at different temperatures.

[0042] Figure 6 The graph shows the isothermal hydrogen desorption performance test results of ball-milled MgH2 without catalyst prepared in Example 1 at different temperatures.

[0043] Figure 7 The graph shows the isothermal hydrogen absorption performance test results of ball-milled MgH2 without catalyst prepared in Example 1 at different temperatures.

[0044] Figure 8JMAK model and Arrhenius plot of Ni / Mo2N-MgH2 composite material prepared in Example 1 at different temperatures;

[0045] Figure 9 JMAK model and Arrhenius plot of ball-milled MgH2 without catalyst prepared in Example 1 at different temperatures;

[0046] Figure 10 The bar chart shows the hydrogen desorption cycle life of the Ni / Mo2N-MgH2 composite material prepared in Example 1. Detailed Implementation

[0047] The present invention will be further described in detail through embodiments and with reference to the accompanying drawings, but this is not intended to limit the scope of the invention.

[0048] Example 1

[0049] This embodiment provides a method for preparing a nickel-doped nitride catalyst, the method comprising the following steps:

[0050] Step 1) Preparation of Ni / Mo2N precursor: First, Ni(CH3COO)2·4H2O (3.0 mmol) and (NH4)6Mo7O 24 • 0.43 mmol of 4H₂O was dissolved in 80 mL of deionized water and stirred magnetically. Then, polyvinylpyrrolidone was slowly added dropwise to the mixture. Stirring continued until completely dissolved, and then the solution was transferred to a 100 mL autoclave and kept at room temperature. After naturally cooling to room temperature, the hydrothermal sample deposit was collected.

[0051] Step 2) Wash several times with deionized water and anhydrous ethanol, collect the precipitate after centrifugation, and then dry it in a drying oven. The urea and dried powder are then transferred to a tube furnace and calcined under a flowing gas stream. After naturally cooling to room temperature, the sample is collected and transferred to a glove box filled with Ar for further use.

[0052] Unless otherwise specified, the conditions for hydrothermal reaction and tubular furnace calcination in this invention are all at a hydrothermal temperature of 180°C for 15 hours and a tubular furnace calcination temperature of 500°C for 2.5 hours.

[0053] Unless otherwise specified, the stirring, centrifugation, and washing conditions of this invention are all the same: stirring for 20 minutes, centrifugation speed of 6000 r / min, centrifugation time of 5 minutes, and centrifugation times of 4.

[0054] Unless otherwise specified, the drying conditions of this invention are all carried out at a drying temperature of 60°C and a drying time of 12 hours.

[0055] To demonstrate the successful preparation of Ni / Mo2N in step 1, XRD analysis was performed. The test results are as follows: Figure 1 As shown, the diffraction peaks of Ni / Mo2N agree well with the PDF cards of Ni / Mo2N (PDF#04-0850Ni, PDF#25-1366Mo2N). The test results indicate that Ni / Mo2N was successfully synthesized with high purity and high crystallinity.

[0056] To verify the microstructure of the Ni / Mo2N obtained in step 1, SEM testing was performed. The test results are as follows: Figure 2 As shown, SEM testing revealed that the microstructure of Ni / Mo2N is a plate-like shell.

[0057] A method for preparing a Ni / Mo2N-based MgH2 hydrogen storage material, specifically the application of Ni / Mo2N as a catalyst in MgH2 hydrogen storage, is disclosed. The preparation method involves mixing Ni / Mo2N with MgH2 under argon atmosphere at a Ni / Mo2N addition amount of 6wt%, followed by high-energy ball milling at a ball-to-material ratio of 40:1, a ball milling speed of 400 rpm, and a total ball milling time of 10 h. The high-energy ball milling is performed using both forward and reverse rotation methods, with a single milling time of 12 min and a 6 min interval between milling cycles. This yields a MgH2-based hydrogen storage material with a Ni / Mo2N addition amount of 6wt%, named MgH2-6Ni / Mo2N.

[0058] To demonstrate the hydrogen storage performance of the MgH2-6Ni / Mo2N composite material, TPD and PCT tests were conducted.

[0059] To verify the initial hydrogen release temperature and hydrogen release capacity of the MgH2-6Ni / Mo2N composite material, a TPD test was performed on the hydrogen storage material. The test results are as follows: Figure 3 As shown, the initial hydrogen release temperature of the catalyst-doped hydrogen storage material is 186℃ and the hydrogen release amount is 6.9wt%.

[0060] To demonstrate the hydrogen absorption and desorption capabilities of the MgH2-6Ni / Mo2N composite material and ball-milled MgH2 at different temperatures, the isothermal hydrogen absorption / desorption properties of the hydrogen storage material were tested, such as... Figures 3-5 As shown in the figure, MgH2-6Ni / Mo2N exhibits excellent low-temperature hydrogen storage performance, capable of absorbing a certain amount of hydrogen in a short time. At 125℃, it can rapidly absorb 5.14 wt% hydrogen in 10 minutes, and at a lower dehydrogenation temperature of 265℃, it can release 5.91 wt% hydrogen within 30 minutes. At 325℃, it can essentially achieve complete hydrogen release within 10 minutes. Figures 6-7Ball milling of MgH2 at 300℃ for 30 min released only 0.73 wt%, while at 125℃ it absorbed 0.18 wt% H2 in 10 min.

[0061] To demonstrate the excellent kinetic properties of the MgH2-6Ni / Mo2N composite material, the dehydrogenation activation energy of the composite material with ball-milled MgH2 was calculated as follows: Figures 8-9 The activation energy of the composite material after adding Ni / Mo2N is 76.35 kJ / mol, and that of ball-milled MgH2 is 149.14 kJ / mol.

[0062] To demonstrate the stability of the catalytically active material in the MgH2-6Ni / Mo2N composite material, the cycling performance of the hydrogen storage material was tested. The specific test method was as follows: Cycling performance was tested using PCT at 310℃, with a hydrogen pressure of 2.5 MPa. The test analysis results are as follows: Figure 10 As shown, after 10 cycles, the actual hydrogen capacity of MgH2-6Ni / Mo2N remained at 6.593 wt%, which is equivalent to 97.8% of the capacity retention rate compared with the first cycle. This indicates that MgH2-6Ni / Mo2N exhibits stable dehydrogenation and has good cycle stability.

[0063] The test results above demonstrate that Ni / Mo2N, as a catalyst, can significantly improve the hydrogen absorption / desorption capacity of MgH2.

[0064] To demonstrate the effects of Ni / Mo2N and Mo2N on the hydrogen storage performance of MgH2, Comparative Examples 1 and 2 are provided. Comparative Example 1 compares the initial hydrogen release temperature and hydrogen absorption / desorption performance and activation energy at different temperatures of MgH2-6Ni / Mo2N and ball-milled MgH2 as hydrogen storage materials. Comparative Example 2 compares the initial hydrogen release temperature of MgH2-6Ni / Mo2N and MgH2-6Mo2N as hydrogen storage materials.

[0065] Example 2

[0066] This embodiment provides a method for preparing a transition metal nitride catalyst, which includes the following steps:

[0067] Step 1) Preparation of Mo2N: First, (NH4)6Mo7O 24 · 4H2O (3.5g) and hexamethylenetetramine (6.0g) were dissolved separately in 50ml of deionized water and stirred magnetically. After complete dissolution, the two solutions were mixed and allowed to stand for 5h. The precipitated white crystals were then collected and dried.

[0068] Step 2) Place the dried sample and urea into a quartz boat and transfer it to a tube furnace. Calcinate the sample under a flowing airflow. After naturally cooling to room temperature, collect the sample and transfer it to a glove box for further use.

[0069] The calcination conditions for the tubular furnace in this invention are not specifically specified, but are 800℃ for 2 hours.

[0070] Comparative Example 1

[0071] A method for preparing a MgH2 hydrogen storage material is described. Unless otherwise specified, the steps are the same as in Example 1, except that Ni / Mo2N is not added as a catalyst during the ball milling process; instead, only 0.5g of MgH2 is weighed and ball-milled to obtain the MgH2 hydrogen storage material, referred to as ball-milled MgH2. The composite material MgH2-6Ni / Mo2N and the ball-milled MgH2 are subjected to TPD, PCT, and activation energy tests.

[0072] The TPD test results of MgH2-6Ni / Mo2N and ball-milled MgH2 are as follows: Figure 3 As shown, the initial hydrogen desorption temperature of ball-milled MgH2 is 322.1℃. After adding Mo2N, the initial hydrogen desorption temperature of the composite material decreases to 288.3℃. However, after adding MgH2-6Ni / Mo2N, the initial hydrogen desorption temperature of the composite material further decreases to 186.3℃. PCT test results are as follows... Figure 4-6 As shown, the MgH2-6Ni / Mo2N composite material released 5.91 wt% hydrogen at 265℃ for 30 min and absorbed 5.84 wt% hydrogen at 125℃ for 30 min. Compared with ball-milled MgH2, it released 0.93 wt% hydrogen at 300℃ for 30 min and absorbed 1.56 wt% hydrogen at 250℃ for 30 min. The activation energy test results are as follows. Figure 8-9 As shown, the activation energy of ball-milled MgH2 is 149.14 kJ / mol, while the activation energy of MgH2-6Ni / Mo2N is 76.35 kJ / mol, which is 71.79 kJ / mol lower than that of ball-milled MgH2.

[0073] Comparative Example 2

[0074] A method for preparing a MgH2-6Mo2N composite material is described. Unless otherwise specified, the steps are the same as in Example 1, except that Ni(CH3COO)2·4H2O is not added in step 1. MgH2-6Mo2N is obtained by ball milling Mo2N obtained in Example 2 with MgH2. The composite materials MgH2-6Ni / Mo2N and MgH2-6Mo2N are subjected to TPD testing.

[0075] The TPD test results of MgH2-6Ni / Mo2N and MgH2-6Mo2N are as follows: Figure 3As shown, the initial hydrogen desorption temperature of MgH2-6Mo2N is 102℃ higher than that of MgH2-6Ni / Mo2N.

[0076] Combining the results of Examples 1 and 2 with those of Comparative Examples 1 and 2, it can be seen that the initial hydrogen release temperature of MgH2-6Ni / Mo2N is reduced by 102℃ and 135℃, respectively, compared with MgH2-6Mo2N and ball-milled MgH2. At 265℃, the MgH2-6Ni / Mo2N composite material releases 5.91wt% of hydrogen within 30 minutes and absorbs 5.14wt% of H2 within 10 minutes at 125℃, while ball-milled MgH2 releases only 0.73wt% of H2 within 30 minutes at 300℃ and absorbs only 0.18wt% of H2 within 10 minutes at 125℃. Simultaneously, the activation energy is reduced by 73kJ / mol compared with ball-milled MgH2. In conclusion, the addition of Ni / Mo2N significantly improves the hydrogen storage performance of MgH2.

Claims

1. A nickel-doped nitride catalyst, characterized in that: The catalyst comprises elements Ni, Mo, and N, and is a Ni / Mo₂N catalyst in the form of shell-shaped nanosheets. The preparation method of the nickel-doped nitride catalyst includes the following steps: Step 1), Ni(CH3COO)2·4H2O and (NH4)6Mo7O 24 • 4H2O and polyvinylpyrrolidone were dissolved in deionized water and stirred magnetically. After complete dissolution, the solution was transferred to an autoclave and kept at a constant temperature for a period of time. After natural cooling to room temperature, the hydrothermal sample precipitate was collected. The autoclave was kept at 180 °C for 15 h. Step 2) Wash the precipitate several times with deionized water, collect the precipitate after centrifugation, dry it, and then transfer the urea and the dried precipitate to a tube furnace in sequence. Calcinate it for a period of time under a flowing argon gas flow. After naturally cooling to room temperature, collect the sample and transfer it to a glove box filled with Ar to obtain the nickel-doped nitride catalyst. In step 2), the washing conditions are washing with deionized water and centrifuging 3-5 times, with a centrifugation speed of 5000 r / min-6000 r / min and a centrifugation time of 3 min-5 min; the drying conditions are drying at 60 ℃-100 ℃ for 12 h; and the calcination conditions are calcination at 500 ℃ under argon atmosphere for 2 h-3 h.

2. The nickel-doped nitride catalyst according to claim 1, characterized in that: In step 1), the Ni(CH3COO)2·4H2O is 3.0 mmol, and (NH4)6Mo7O is... 24 The concentrations of Ni(CH3COO)2·4H2O, (NH4)6Mo7O were 0.43 mmol, H2O was 80 mL, and polyvinylpyrrolidone was 2.2 mmol. The magnetic stirring time was between 15 min and 30 min. 24 • 4H2O and polyvinylpyrrolidone should be added slowly and sequentially. In step 2), the amount of urea is 30 mmol.

3. An application of a hydrogen storage material using the nickel-doped nitride catalyst of claim 1 to dope MgH2 in the field of hydrogen storage, characterized in that: The nickel-doped nitride catalyst and MgH2 were mixed in a certain mass ratio and ball-milled under certain conditions to obtain a hydrogen storage material with Ni / Mo2N catalyst doped with MgH2. When the catalyst doping amount is 2 wt.%-6 wt.%, the initial hydrogen release temperature of the system drops to 175 ℃-186 ℃, and the hydrogen release amount reaches 6.1 wt.%-6.9 wt.%. During isothermal hydrogen release, the system can completely release hydrogen at 325 ℃, and the hydrogen release amount reaches 6.3 wt.%-6.9 wt.% within 6 min. During isothermal hydrogen absorption, even at a temperature as low as 100 ℃, the system can still absorb 5.0 wt.%-5.3 wt.% of hydrogen within 30 min.

4. The application of the nickel-doped nitride catalyst-doped MgH2 hydrogen storage material according to claim 3 in the field of hydrogen storage is characterized in that: The ball milling conditions are as follows: argon as the protective atmosphere, ball-to-material ratio of 40:1, ball milling speed of 400-450 r / min, and ball milling time of 10-12 h.

5. The application of the nickel-doped nitride catalyst-doped MgH2 hydrogen storage material according to claim 3 in the field of hydrogen storage is characterized in that: After recycling, the sample exhibited good hydrogen storage reversibility and stable cycling performance. After 10 cycles, the actual hydrogen capacity retention rate was equivalent to 97.8% of the capacity of the first cycle.

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