A magnesium-based hydrogen storage material modified with layered transition metal molybdenum boride loaded with nickel oxide

Abstract

This invention relates to the field of hydrogen energy storage technology, and specifically discloses a layered transition metal molybdenum boride (NiO@Mo) supported on nickel oxide. 4 / 3 B2-MBene-modified magnesium-based hydrogen storage materials and their preparation methods: This material uses MgH2 as the matrix and adds NiO@Mo 4 / 3 B2-MBene was prepared as a modifier. Mo... 4 / 3 B2-MBene is derived from (Mo 2 / 3 Y 1 / 3 The 2AlB2-MAB phase precursor was prepared by selectively etching with hydrofluoric acid to remove Al and Y atoms, followed by intercalation, layering, and vacuum drying; NiO@Mo 4 / 3 B2-MBene as layered Mo 4 / 3 B2-MBene was used as the matrix material, and a solution was prepared by adding Ni(NO3)2·6H2O, urea and NaOH for hydrothermal reaction, followed by centrifugation to remove impurities, vacuum drying and muffle furnace calcination to obtain NiO@Mo. 4 / 3 B2-MBene modified magnesium-based hydrogen storage materials were prepared by mechanical ball milling. The NiO@Mo prepared in this invention... 4 / 3 In B2-MBene modifier, Mo 4 / 3 B2-MBene possesses a unique layered structure confinement effect and inherent catalytic activity. Synergistically with in-situ supported NiO, it improves the hydrogen storage performance of MgH2, significantly reducing the hydrogen desorption temperature of MgH2 and enhancing hydrogen desorption kinetics and cycle stability. This magnesium-based hydrogen storage material can release 5.9 wt% H2 within 5 min at 300 °C, and maintains a capacity retention of 95.8% after 50 cycles, outperforming single-doped NiO or single-doped Mo. 4 / 3 B2-MBene MgH2 and undoped MgH2 provide a new approach for performance regulation of magnesium-based hydrogen storage materials, and have good prospects for practical application.

Description

Technical Field

[0001] This invention belongs to the field of hydrogen energy storage, specifically relating to a NiO@Mo 4 / 3 B2-MBene modified magnesium-based hydrogen storage material. Background Technology

[0002] As a potential alternative to fossil fuels, hydrogen energy is receiving increasing attention, offering an effective way to reduce greenhouse gas emissions and address the challenges posed by the depletion of fossil fuel resources. However, developing safe and reliable hydrogen storage and transportation technologies is crucial for the large-scale application of hydrogen energy. Various solid-state hydrogen storage materials, such as metal hydrides, porous adsorbents, and coordinated metal hydrides, have shown the potential to effectively solve many problems in hydrogen production and application. Magnesium hydride (MgH2), with a theoretical hydrogen storage capacity of 7.6 wt%, good reversibility, and abundant natural reserves, is considered a promising candidate material for solid-state hydrogen storage. However, its widespread application is limited by two main drawbacks: the high hydrogen desorption temperature caused by its inherently slow kinetics, and the high thermodynamic stability required to control the hydrogen absorption and desorption process. Therefore, in-depth research on improving the hydrogen absorption and desorption performance of MgH2 is crucial for advancing its practical application.

[0003] Introducing active catalytic components is an effective strategy for regulating the performance of magnesium-based hydrogen storage materials, and it is widely used to improve the hydrogen storage performance of MgH2. In recent years, layered transition metal borides (MBene) have attracted much attention due to their layered structure similar to MXene and their inherent boron-rich chemical environment. Currently, research on MBene mainly focuses on its structure, synthesis methods, and applications in electrocatalysis, photocatalytic hydrogen production, electrochemical energy storage, sensors, and targeted drug delivery. Research reports on the catalytic effect of MBene on hydrogen storage materials are relatively few. Transition metal borides are highly efficient active catalytic components that can improve the hydrogen storage performance of MgH2. They can act as active nucleation sites for reaction products, promoting the adsorption and dissociation of hydrogen within the material, thereby improving the hydrogen adsorption and desorption kinetics of MgH2. Furthermore, due to their unique electronic configuration and crystal structure, transition metals and their oxides can effectively weaken the Mg-H bond, thereby reducing the thermodynamic stability of MgH2.

[0004] Recent studies have shown that composite catalysts composed of multiple components can significantly improve the hydrogen adsorption and desorption performance of MgH2 through synergistic interfacial interactions. However, the synergistic potential of combining transition metal oxides with emerging two-dimensional transition metal borides has not been fully explored. This invention employs a hydrothermal method to in-situ support NiO nanoparticles on Mo... 4 / 3 NiO@Mo was prepared on the surface of B2-MBene nanosheets. 4 / 3The B2-MBene composite catalyst was then introduced into MgH2 via mechanical ball milling, aiming to improve the hydrogen absorption and dehydrogenation performance of MgH2 by utilizing the synergistic effect between different components. Summary of the Invention

[0005] This invention aims to introduce for the first time a layered transition metal boride loaded with nickel oxide into the field of magnesium-based hydrogen storage materials, thereby solving the technical bottlenecks faced by existing magnesium-based hydrogen storage materials, such as high hydrogen desorption temperature, slow reaction kinetics, and insufficient cycle stability.

[0006] To achieve the above-mentioned technical objectives and effects, the present invention provides the following technical solution: A layered transition metal boride (NiO@Mo) supported on nickel oxide 4 / 3 B2-MBene modified magnesium-based hydrogen storage material, wherein the magnesium-based hydrogen storage material uses MgH2 as the matrix material and NiO@Mo 4 / 3 B2-MBene is a modifier, and the layered Mo 4 / 3 B2-MBene has a few-layer or monolayer structure with ordered molybdenum vacancy defects and an interlayer spacing of 10.39 Å. The NiO@Mo 4 / 3 B2-MBene is an in-situ loading of NiO nanoparticles onto Mo. 4 / 3 B2-MBene on.

[0007] Furthermore, the NiO@Mo 4 / 3 The mass of B2-MBene is 1% to 30% of the total mass of the magnesium-based hydrogen storage material.

[0008] Furthermore, the NiO@Mo 4 / 3 The mass of B2-MBene is 10% of the total mass of the magnesium-based hydrogen storage material.

[0009] On the other hand, the present invention also provides a method for preparing the magnesium-based hydrogen storage material as described above, comprising the following steps: (1) Preparation of layered Mo 4 / 3 B2-MBene: with (Mo 2 / 3 Y 1 / 3 Using 2AlB2-MAB as a precursor, the Al and Y atomic layers were selectively removed by etching with hydrofluoric acid solution. After centrifugation to remove impurities, intercalation and layering were performed. The colloidal supernatant was collected and vacuum dried to obtain layered Mo. 4 / 3 B2-MBene powder; (2) Preparation of NiO@Mo 4 / 3 B2-MBene material, with layered Mo 4 / 3Using B2-MBene powder as the matrix material, Ni(NO3)2·6H2O as the nickel source and urea as the precipitant were used for uniform stirring. NaOH solution was then added dropwise to adjust the pH to 10, and stirring continued. The mixed solution was then transferred to a high-pressure reactor for hydrothermal reaction. After the reaction, the solution was centrifuged to remove impurities, and the resulting precipitate was dried in a vacuum drying oven. Finally, the precursor was calcined in a muffle furnace to obtain NiO@Mo. 4 / 3 B2-MBene powder; (3) Preparation of magnesium-based hydrogen storage materials: magnesium hydride is reacted with the NiO@Mo obtained in step (2). 4 / 3 B2-MBene powder was weighed according to stoichiometric ratio and subjected to high-energy mechanical ball milling under an inert atmosphere to obtain MgH2 + 10 wt% NiO@Mo. 4 / 3 B2-MBene hydrogen storage material, which contains 10 wt% NiO@Mo 4 / 3 MgH2 of B2-MBene.

[0010] Further, in step (1), the mass concentration of the hydrofluoric acid solution is 40%, (Mo 2 / 3 Y 1 / 3 The ratio of AlB2-MAB powder to 40% HF solution was 1 g: 25 mL; the selective etching conditions were 0–100 °C with magnetic stirring for 1–60 h; the centrifugation speed was 1000–10000 r / min, and the mixture was centrifuged 6 times until the supernatant was neutral.

[0011] Further, in step (1), the intercalation and layering treatment is to disperse the centrifuged precipitate in a 1% to 20% tetramethylammonium hydroxide (TMAOH) solution and perform ultrasonic-assisted intercalation and layering treatment; the vacuum drying is to dry at 60 °C for 6 h.

[0012] Further, in step (2), the Mo 4 / 3 The molar ratio of B2-MBene, Ni(NO3)2·6H2O, and urea is 1:1:1; the concentration of the NaOH solution is 1.0 mol·L⁻¹. -1 The hydrothermal reaction conditions were: holding at 150 °C for 12 h; the vacuum drying conditions were: drying at 60 °C for 6 h; and the muffle furnace calcination conditions were: calcination at 3 °C / min. -1 The heating rate was increased to 300 °C and held at that temperature for 2.5 h.

[0013] Furthermore, in step (3), the inert atmosphere is high-purity argon, and the O2 content is ≤0.1 ppm and the H2O content is ≤0.1 ppm under the argon atmosphere; the mechanical ball milling adopts a high-energy ball mill, the ball milling speed is 100~800 r / min, the ball milling time is 1~50 h, the ball-to-material ratio is 50:1, and the ball milling process is paused for 5 min every 15 min.

[0014] On the other hand, the present invention also provides a NiO@Mo according to the above. 4 / 3 The application of B2-MBene modified magnesium-based hydrogen storage materials in the field of solid-state hydrogen energy storage is applied to solid-state hydrogen storage scenarios such as hydrogen energy storage and transportation and fuel cell hydrogen supply.

[0015] Compared with the prior art, the beneficial effects of the present invention are: This invention is the first to use layered Mo 4 / 3 B2-MBene is introduced into magnesium-based hydrogen storage materials, which not only utilize Mo 4 / 3 B2-MBene's unique layered structure enables nano-confinement of MgH2, inhibiting the growth and aggregation of magnesium hydride particles, and also utilizes Mo... 4 / 3 NiO@Mo was obtained by loading NiO with B2-MBene as the matrix material. 4 / 3 B2-MBene exhibits significantly better catalytic performance than single-doped NiO or Mo. 4 / 3 The synergistic effect of B2-MBene and pure MgH2 significantly reduces the activation energy of the hydrogen desorption reaction and improves the hydrogen storage performance of MgH2. (MgH2 + 10 wt% NiO@Mo) 4 / 3 B2-MBene can undergo hydrogen absorption at room temperature. At 150 °C, it can absorb 4.7 wt% of hydrogen in 5 minutes, and at 300 °C, it can release 5.9 wt% of hydrogen in 5 minutes, which fully demonstrates that this magnesium-based hydrogen storage material has a significant kinetic enhancement effect and effective hydrogen storage performance.

[0016] The MgH2 + 10 wt% NiO@Mo prepared by this invention 4 / 3 B2-MBene hydrogen storage material exhibits excellent cycle stability, maintaining a capacity retention rate of 95.8% after 50 hydrogen adsorption / desorption cycles, thus solving the problem of decreased catalytic activity caused by the easy aggregation of traditional catalytic additives. Attached Figure Description

[0017] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description of the specific embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] This accompanying drawing is a schematic diagram of functional and connection relationships, and is for illustrative purposes only, not restrictive. The shape, relative proportions, and arrangement of components can be adjusted for engineering purposes without departing from the claims. Figure 1 NiO@Mo in this embodiment of the invention 4 / 3 Flowchart of the preparation method of B2 catalyst; Figure 2 In the embodiments of the present invention (Mo) 2 / 3 Y 1 / 3 )2AlB2-MAB and etched Mo 4 / 3 XRD pattern of B2-MBene; Figure 3 Mo in the embodiments of the present invention 4 / 3 SEM images of B2-MBene; Figure 4 NiO@Mo in this embodiment of the invention 4 / 3 SEM and EDS images of B2-MBene; Figure 5 In this embodiment of the invention, NiO is supported on Mo. 4 / 3 XRD images before and after B2-MBene; Figure 6 NiO@Mo in this embodiment of the invention 4 / 3 TEM and HRTEM images of B2-MBene; Figure 7 NiO@Mo in this embodiment of the invention 4 / 3 SAED images of B2-MBene; Figure 8 NiO@Mo in this embodiment of the invention 4 / 3 Ni 2p XPS spectrum of B2-MBene; Figure 9 NiO@Mo in this embodiment of the invention 4 / 3 Mo 3d XPS spectrum of B2-MBene; Figure 10 NiO@Mo in this embodiment of the invention 4 / 3 B1s XPS spectrum of B2-MBene; Figure 11 In the embodiments of the present invention, MgH2 + 10 wt%X (X = Mo) 4 / 3 B2-MBene, NiO and NiO@Mo 4 / 3 Hydrogen desorption curves of B2-MBene hydrogen storage material and pure MgH2 from room temperature to 400 °C; Figure 12In the embodiments of the present invention, MgH2 + 10 wt%X (X = Mo) 4 / 3 B2-MBene, NiO and NiO@Mo 4 / 3 Isothermal hydrogen desorption curves of B2-MBene hydrogen storage material and pure MgH2 under 300 ℃ and 0.001MPa H2 conditions; Figure 13 In the embodiments of the present invention, MgH2 + 10 wt%X (X = Mo) 4 / 3 B2-MBene, NiO and NiO@Mo 4 / 3 Hydrogen absorption curves of B2-MBene hydrogen storage material and pure MgH2 from room temperature to 400 °C; Figure 14 In the embodiments of the present invention, MgH2 + 10 wt%X (X = Mo) 4 / 3 B2-MBene, NiO and NiO@Mo 4 / 3 Isothermal hydrogen absorption curves of B2-MBene hydrogen storage material and pure MgH2 under 150 ℃ and 6 MPa H2 conditions; Figure 15 In this embodiment of the invention, MgH2 + 10 wt% NiO@Mo 4 / 3 Isothermal hydrogen desorption curves of B2-MBene at 225 ℃, 250 ℃, 275 ℃, 300 ℃ and 325 ℃; Figure 16 The isothermal hydrogen desorption curves of pure MgH2 at 325 ℃, 350 ℃, 375 ℃ and 400 ℃ in the embodiments of the present invention are shown. Figure 17 In this embodiment of the invention, MgH2 + 10 wt% NiO@Mo 4 / 3 Isothermal hydrogen absorption curves of B2-MBene at 50 ℃, 75 ℃, 100 ℃, 125 ℃ and 150 ℃; Figure 18 The isothermal hydrogen absorption curves of pure MgH2 at 175 ℃, 200 ℃, 225 ℃ and 250 ℃ in the embodiments of the present invention are shown. Figure 19 In this embodiment of the invention, MgH2 + 10 wt% NiO@Mo 4 / 3 Cyclic performance graph of B2-MBene; Figure 20 In this embodiment of the invention, MgH2 + 10 wt% NiO@Mo 4 / 3 XRD patterns of B2-MBene hydrogen storage material after ball milling, after 5 hydrogen release cycles, and after 5 hydrogen absorption cycles; Figure 21In this embodiment of the invention, MgH2 + 10 wt% NiO@Mo 4 / 3 TEM and HRTEM images of the B2-MBene hydrogen storage material after hydrogen absorption; Figure 22 In this embodiment of the invention, MgH2 + 10 wt% NiO@Mo 4 / 3 SAED image of B2-MBene hydrogen storage material after hydrogen absorption; Figure 23 In this embodiment of the invention, MgH2 + 10 wt% NiO@Mo 4 / 3 Ni 2p XPS spectra of B2-MBene hydrogen storage material after ball milling, hydrogen release, and hydrogen absorption; Figure 24 In this embodiment of the invention, MgH2 + 10 wt% NiO@Mo 4 / 3 Mo 3d XPS spectra of B2-MBene hydrogen storage material after ball milling, hydrogen release, and hydrogen absorption; Figure 25 In this embodiment of the invention, MgH2 + 10 wt% NiO@Mo 4 / 3 B1s XPS spectra of B2-MBene hydrogen storage material after ball milling, hydrogen release, and hydrogen absorption; Figure 26 In the embodiments of the present invention, ln[-ln(1-] is pure MgH2. α )] and ln t Relationship curve; Figure 27 In this embodiment of the invention, MgH2 + 10 wt% NiO@Mo 4 / 3 B2-MBene hydrogen storage material ln[-ln(1- α )] and ln t Relationship curve; Figure 28 The Arrhenius curve of pure MgH2 in the embodiments of the present invention; Figure 29 In this embodiment of the invention, MgH2 + 10 wt% NiO@Mo 4 / 3 Arrhenius curve of B2-MBene hydrogen storage material; Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] 1. Material preparation 1.1. Raw materials The raw materials used in this invention include magnesium hydride (MgH2, 97%, Aladdin), hydrofluoric acid (HF, 40%, Aladdin), tetramethylammonium hydroxide (TMAOH, 25% aqueous solution, Aladdin), and (Mo 2 / 3 Y 1 / 3 )2AlB2-MAB (purchased from Foshan Xinxi Technology Co., Ltd.), nickel nitrate hexahydrate (Ni(NO3)2·6H2O, 99%, Aladdin), sodium hydroxide (NaOH, 98%, Aladdin) and urea (urea, 99%, Aladdin).

[0021] 1.2, Mo 4 / 3 Synthesis of B2-MBene Put 2 g(Mo 2 / 3 Y 1 / 3 )2AlB2-MAB powder was added to 50 mL of 40% HF solution and magnetically stirred at 40 °C for 24 h to achieve (Mo 2 / 3 Y 1 / 3 Selective etching of the Al layer and Y atoms in 2AlB2-MAB. After the etching reaction, the mixture was centrifuged six times at 8000 r / min until the pH of the supernatant reached neutral, ensuring complete removal of residual HF and reaction byproducts. The precipitate was redispersed in 20 mL of 12.5% ​​tetramethylammonium hydroxide (TMAOH) solution, and intercalation-assisted separation was promoted by ultrasound. Finally, the colloidal supernatant was collected and vacuum dried at 60 °C for 6 h to obtain a few-layer Mo. 4 / 3 B2-MBene powder.

[0022] 1.3, NiO@Mo 4 / 3 Synthesis of B2-MBene First, at room temperature, 1.0 mmol Mo 4 / 3 B2, 1.0 mmol Ni(NO3)2·6H2O, and 1.0 mmol urea were sequentially dispersed in 60 mL of deionized water and stirred evenly with a magnetic stirrer for 30 minutes. Then, 1.0 mol·L⁻¹ urea solution was added dropwise. -1 The mixture was stirred in NaOH solution until the pH reached 10, and stirred for another 30 minutes. The resulting mixture was transferred to a high-pressure reactor and heat-treated in a forced-air drying oven at 150 °C for 12 hours, then allowed to cool naturally to room temperature. Centrifugation was then performed, and the precipitate was washed alternately with deionized water and anhydrous ethanol. The collected product was dried under vacuum at 60 °C for 6 hours to obtain a green precipitate, which was then ground into a fine powder. Finally, the obtained precursor was placed in a muffle furnace and heated at 3 °C·min.-1 The material was calcined at 300 °C for 2.5 hours and then naturally cooled to room temperature to obtain NiO@Mo. 4 / 3 B2. The preparation method of NiO is the same as the above process, except that Mo is not added. 4 / 3 B2.

[0023] 1.4, MgH2 + 10 wt%X (X=NiO, Mo 4 / 3 B2-MBene and NiO@Mo 4 / 3 Preparation of B2-MBene hydrogen storage materials The magnesium-based hydrogen storage material of this invention is synthesized using a mechanical ball milling method. Accurate weighing of MgH2 and three catalysts (NiO, Mo) is performed. 4 / 3 B2-MBene and NiO@Mo 4 / 3 The stoichiometry of B2-MBene was used to prepare MgH2 + 10 wt%X (X = NiO, Mo) 4 / 3 B2-MBene and NiO@Mo 4 / 3 B2-MBene hydrogen storage material. All operations were conducted under a strictly controlled inert atmosphere. The mixture was sealed in a stainless steel ball mill jar and loaded into a glove box protected by high-purity argon (Etelux Lab 2000, O2 content ≤0.1ppm, H2O content ≤0.1ppm). Subsequently, it was ball-milled for 8 hours at 400 r / min using a high-energy ball mill (Pulverisette 7), with a ball-to-material ratio controlled at 50:1. To prevent excessively high temperatures during ball milling from affecting material properties, a 5-minute pause was taken every 15 minutes to ensure system temperature stability.

[0024] 2. Hydrogen storage performance measurement All hydrogenation and dehydrogenation experiments were conducted on a laboratory-made Sievert apparatus. In the experiments, the ball-milled MgH₂ + 10 wt%X (X = NiO, Mo) 4 / 3 B2-MBene and NiO@Mo 4 / 3 The B2-MBene hydrogen storage material was loaded into a reactor under an inert atmosphere for hydrogen storage performance testing, including isothermal hydrogen absorption and desorption tests at different temperatures and variable-temperature hydrogen absorption and desorption tests involving heating from room temperature to 400 °C. The heating rate for the variable-temperature hydrogen absorption and desorption tests was 2 °C·min. -1 Hydrogen absorption and desorption tests were conducted at hydrogen pressures of 6 MPa and 0.001 MPa, respectively. Furthermore, tests were performed at a constant temperature of 300 °C on MgH₂ + 10wt%NiO@Mo. 4 / 3 The hydrogen absorption and desorption cycle performance of the B2-MBene hydrogen storage material was tested.

[0025] 3. Structural characterization The morphology and elemental distribution of the samples were observed and analyzed using a transmission electron microscope (TEM; FEI TECNAI G2 / F30, USA) with its attached high-resolution transmission electron microscope (HRTEM) and selected area electron diffraction (SAED) functions, as well as a scanning electron microscope (SEM; Zeiss Sigma 300, Germany) equipped with an energy dispersive spectroscopy (EDS) system. Phase identification was performed using an X-ray diffractometer (XRD; Rigaku D / MAX 2500V, Japan) at a test condition of 40 kV × 30 mA and a scan rate of 5°·min. -1 The step size was 0.02°, and the scanning range was 5° to 80°. The valence state distribution of elements was determined using X-ray photoelectron spectroscopy (XPS; ESCALAB 250Xi Microprobe).

[0026] The invention will now be further described with reference to the accompanying drawings.

[0027] Layered Mo 4 / 3 B2-MBene is produced by the precursor (Mo) 2 / 3 Y 1 / 3 It is synthesized by removing the Al atomic layer and Y atoms in 2AlB2-MAB through HF etching.

[0028] Figure 1 NiO@Mo in this embodiment of the invention 4 / 3 Flowchart of the preparation method for B2 catalyst. First, selective etching (Mo) is performed using an aqueous HF solution. 2 / 3 Y 1 / 3 In the AlB2-MAB precursor, Al layers and Y atoms are present. During this process, the removal of Y atoms directly introduces Mo vacancy defects. Subsequently, intercalation and delamination are achieved using TBAOH, ultimately yielding few-layer or monolayer Mo. 4 / 3 B2-MBene. Ordered Mo vacancy defects are one of the most prominent structural features of this MBene. Next, 1.0 mmol Mo... 4 / 3 B2, 1.0 mmol Ni(NO3)2·6H2O, and 1.0 mmol urea were sequentially dispersed in 60 mL of deionized water and stirred evenly with a magnetic stirrer for 30 minutes. Then, 1.0 mol·L⁻¹ urea solution was added dropwise. -1The mixture was stirred in NaOH solution until the pH reached 10, and stirred for another 30 minutes. The resulting mixture was transferred to a high-pressure reactor and heat-treated in a forced-air drying oven at 150 °C for 12 hours, then allowed to cool naturally to room temperature. Centrifugation was then performed, and the precipitate was washed alternately with deionized water and anhydrous ethanol. The collected product was dried under vacuum at 60 °C for 6 hours to obtain a green precipitate, which was then ground into a fine powder. Finally, the obtained precursor was placed in a muffle furnace and heated at 3 °C·min. -1 The material was calcined at 300 °C for 2.5 hours and then naturally cooled to room temperature to obtain NiO@Mo. 4 / 3 B2.

[0029] Figure 2 In the embodiments of the present invention (Mo) 2 / 3 Y 1 / 3 )2AlB2-MAB and etched Mo 4 / 3 XRD pattern of B2-MBene. Original (Mo 2 / 3 Y 1 / 3 )2AlB2-MAB contains (Mo 2 / 3 Y 1 / 3 )2AlB2-MAB and small amounts of impurities MoB and Y2O3. After etching, (Mo 2 / 3Y 1 / 3 The diffraction intensity of 2AlB2-MAB decreases, and in 2 θ A new diffraction peak appears at 8.2°, indicating the formation of layered Mo. 4 / 3 B2-MBene. Calculations using Bragg's law revealed that the interlayer spacing ranged from 7.55 Å (2... θ =11.6°) correspondingly increased to 10.39 Å, confirming the expansion of the layered structure, layered Mo 4 / 3 B2-MBene was successfully synthesized. In addition, a small amount of AlF3 impurity was present due to etching.

[0030] Figure 3 Mo in the embodiments of the present invention 4 / 3 The SEM image of B2-MBene shows that it has a sheet-like structure. Figure 4 NiO@Mo in this embodiment of the invention 4 / 3 SEM and EDS images of B2-MBene. The SEM image clearly shows the distribution of NiO nanoparticles within Mo. 4 / 3 On B2-MBene, the EDS image shows that the four elements Mo, B, Ni, and O are evenly distributed, which also confirms the successful loading of NiO. Figure 5 In this embodiment of the invention, NiO is supported on Mo. 4 / 3XRD images before and after B2-MBene show diffraction peaks belonging to NiO after loading. Figure 6 NiO@Mo in this embodiment of the invention 4 / 3 TEM and HRTEM images of B2-MBene, NiO particles dispersed in Mo 4 / 3 On B2-MBene nanosheets, this observation is consistent with SEM results, and HR-TEM images clearly show multiple distinct interfaces within the product. Lattice spacing measurements of selected regions yielded values ​​of 0.271 nm / 0.218 nm and 0.209 nm / 0.148 nm, respectively, which were attributed to (Mo... 2 / 3 Y 1 / 3 (110) / (116) crystal planes of 2AlB2-MAB and (200) / (220) crystal planes of NiO. Figure 7 NiO@Mo in this embodiment of the invention 4 / 3 SAED images of B2-MBene show a series of clear diffraction ring patterns. These diffraction rings correspond to (Mo... 2 / 3 Y 1 / 3 The (110) crystal plane of AlB2-MAB crystal and the (200) and (220) crystal planes of NiO crystal.

[0031] Figure 8-10 NiO@Mo 4 / 3 XPS spectra of Ni 2p, Mo 3d and B 1s of B2-MBene. Figure 8 NiO@Mo in this embodiment of the invention 4 / 3 The Ni 2p XPS spectrum of B2-MBene showed that Ni... 2+ 2p 1 / 2 and 2p 3 / 2 The spin-orbit energy levels have binding energies at 873.4 eV and 855.6 eV, respectively. Signals at 861.7 eV and 879.9 eV originate from the satellite peaks, Ni 2+ This originates from the supported NiO nanoparticles. Figure 9 NiO@Mo in this embodiment of the invention 4 / 3 The Mo 3d XPS spectrum of B2-MBene reveals the existence of multiple valence states of Mo. The binding energies are located at 232.1 / 235.2 eV, 232.8 / 235.8 eV, and 235.1 / 237.5 eV, corresponding to Mo, respectively. 4+ Mo 5+ and Mo 6+ These signals originate from the incomplete oxidation of the Mo surface during the HF treatment process. In NiO@Mo 4 / 3In B2-MBene, the observed Mo-B characteristic bimodal peaks are located at 231.5 eV and 234.2 eV, which are similar to those observed in unloaded Mo. 4 / 3 Compared to B2-MBene, its binding energy did not change significantly, indicating that the original Mo... 4 / 3 The B2-MBene structure remains intact. Figure 10 NiO@Mo in this embodiment of the invention 4 / 3 The B1s XPS spectrum of B2-MBene shows two signals at binding energies of 185.7 eV and 192.9 eV, corresponding to Mo-B-Tz and BO species, respectively. The presence of BO bonds is attributed to the surface oxidation of boron during HF etching. These characterizations confirm that NiO@Mo 4 / 3 Successful synthesis of B2-MBene.

[0032] Three catalysts (Mo) 4 / 3 B2-MBene, NiO and NiO@Mo 4 / 3 B2-MBene was introduced into the MgH2 hydrogen storage material by mechanical ball milling, with the addition amount of each of the three catalysts being 10 wt%.

[0033] To evaluate NiO@Mo 4 / 3 The catalytic effect of B2-MBene on the hydrogen storage performance of MgH2, specifically on the effect of ball-milled MgH2 + 10wt%X (X=Mo) 4 / 3 B2-MBene, NiO and NiO@Mo 4 / 3 Hydrogen absorption and desorption performance tests were conducted on B2-MBene and pure MgH2 samples. Figure 11 In the embodiments of the present invention, MgH2 + 10 wt%X (X = Mo) 4 / 3 B2-MBene, NiO and NiO@Mo 4 / 3 The dehydrogenation curves of B2-MBene hydrogen storage material and pure MgH2 from room temperature to 400 °C are presented, demonstrating the dehydrogenation curves of MgH2 with different catalysts added during heating from room temperature to 400 °C. The dehydrogenation onset temperature of pure MgH2 is as high as 315 °C. The introduction of Mo... 4 / 3 B2-MBene, NiO and NiO@Mo 4 / 3 Following B2-MBene, the initial dehydrogenation temperatures significantly decreased to 259 °C, 213 °C, and 203 °C, respectively. It is noteworthy that NiO@Mo... 4 / 3 After B2-MBene was incorporated into MgH2, its dehydrogenation onset temperature was reduced by 112 °C compared to unmodified MgH2. At 275 °C, MgH2 + 10 wt% NiO@Mo 4 / 3B2-MBene underwent almost complete dehydrogenation, releasing a capacity of 6.2 wt%. Additionally, MgH2 + 10 wt% NiO@Mo 4 / 3 B2-MBene exhibits faster dehydrogenation performance, with a dehydrogenation cutoff temperature compared to MgH2 + 10 wt%Mo. 4 / 3B2-MBene and MgH2 + 10 wt%NiO reduced the temperature by 64 °C and 42 °C, respectively. Figure 12 In this embodiment of the invention, MgH2 + 10 wt%X (X = Mo) 4 / 3 B2-MBene, NiO and NiO@Mo 4 / 3 The isothermal hydrogen desorption curves of B2-MBene hydrogen storage material and pure MgH2 at 300 ℃ and 0.001 MPa H2 conditions, and the isothermal dehydrogenation curve at 300 ℃, show that the amount of H2 released by MgH2 at this temperature is negligible. When Mo is added... 4 / 3 When B2-MBene and NiO were used as catalysts, the amount of H2 released by MgH2 within 10 min was 1.0 wt% and 4.6 wt%, respectively. It is worth noting that NiO@Mo... 4 / 3 The addition of B2-MBene significantly enhanced the dehydrogenation capacity of MgH2, releasing 6.2 wt% H2 within the same time frame. These results indicate that NiO@Mo 4 / 3 B2-MBene effectively reduced the dehydrogenation initiation temperature of MgH2 and improved the dehydrogenation kinetics of MgH2.

[0034] Figure 13 In the embodiments of the present invention, MgH2 + 10 wt%X (X = Mo) 4 / 3 B2-MBene, NiO and NiO@Mo 4 / 3 The hydrogen absorption curves of B2-MBene hydrogen storage material and pure MgH2 from room temperature to 400 °C were compared for the addition of Mo. 4 / 3 B2-MBene, NiO and NiO@Mo 4 / 3 The temperature-programmed hydrogen absorption curve of B2-MBene MgH2 material shows that after the sample was fully dehydrogenated and activated, it was heated from room temperature to 400 °C. During this process, the initial hydrogenation temperature of MgH2 decreased significantly, and the dehydrogenated MgH2 + 10 wt% Mo 4 / 3 B2-MBene, MgH2 + 10 wt%NiO and MgH2 + 10 wt%NiO@Mo 4 / 3 B2-MBene can begin to absorb hydrogen at room temperature. When the temperature is increased from room temperature to 150 °C, the dehydrogenated state MgH2 + 10 wt%Mo 4 / 3The hydrogen absorption capacities of B2-MBene and MgH2 + 10 wt%NiO increased to 1.6 wt% and 3.9 wt%, respectively. Under the same conditions, the original MgH2 absorbed only 0.1 wt% H2, while MgH2 + 10 wt%NiO@Mo 4 / 3 B2-MBene exhibited a hydrogen absorption capacity of up to 4.9 wt%, significantly superior to all other tested samples. Furthermore, Figure 14 In the embodiments of the present invention, MgH2 + 10 wt%X (X = Mo) 4 / 3 B2-MBene, NiO and NiO@Mo 4 / 3 Isothermal hydrogen absorption curves of B2-MBene hydrogen storage material and pure MgH2 under 150 ℃ and 6 MPa H2 conditions, and the dehydrogenated MgH2 + 10 wt% NiO@Mo 4 / 3 B2-MBene absorbed 4.7 wt% H2 within 10 min, consisting of MgH2 + 10 wt% Mo. 4 / 3 B2-MBene and MgH2 + 10 wt% NiO have 2.2 times and 1.5 times the absorption capacity, respectively. Under the same conditions, pure MgH2 can only absorb 0.2 wt% H2, while the absorption capacity of NiO@Mo is significantly higher. 4 / 3 Following B2-MBene, the hydrogen absorption capacity increased by approximately 4.5 wt%. These results collectively indicate that, among the evaluated catalysts, NiO@Mo... 4 / 3B2-MBene exhibits the best catalytic performance for the hydrogen absorption reaction of MgH2. Comparative evaluation of catalytic activity shows that NiO and Mo in this magnesium-based hydrogen storage material... 4 / 3 There is a significant synergistic effect between B2-MBene, and its overall performance is superior to that of any single catalyst.

[0035] To investigate NiO@Mo 4 / 3 The effect of B2-MBene on the hydrogen desorption kinetics of MgH2 was investigated by isothermal hydrogen desorption tests at different temperatures. Figure 15 In this embodiment of the invention, MgH2 + 10 wt% NiO@Mo 4 / 3 The isothermal hydrogen desorption curves of B2-MBene at 225 ℃, 250 ℃, 275 ℃, 300 ℃, and 325 ℃ show a significant difference compared to the negligible H2 release of pure MgH2 at 325 ℃. (MgH2 + 10 wt% NiO@Mo) 4 / 3 B2-MBene achieved a hydrogen release capacity of 6.1 wt% within 5 minutes, representing a 10.5-fold increase. This magnesium-based hydrogen storage material released 6.0 wt% H2 within 30 minutes at 275 °C. Figure 16The figures show the isothermal hydrogen release curves of pure MgH2 at 325 ℃, 350 ℃, 375 ℃ and 400 ℃ in the embodiments of the present invention. Pure MgH2 only begins to release hydrogen at a temperature as high as 319 ℃, and only 2.4 wt% of H2 is released in the same time at 325 ℃.

[0036] Figure 17 In this embodiment of the invention, MgH2 + 10 wt% NiO@Mo 4 / 3 Isothermal hydrogen absorption curves of B2-MBene at 50 ℃, 75 ℃, 100 ℃, 125 ℃ and 150 ℃, respectively. At 50 ℃, MgH2 + 10 wt%NiO@Mo 4 / 3 B2-MBene absorbed 2.5 wt% of hydrogen within 60 min. When the temperature was raised to 150 °C, the hydrogen absorption rate increased significantly, absorbing 4.8 wt% of H2 and reaching saturation in just 10 min. Figure 18 The figures show the isothermal hydrogen absorption curves of pure MgH2 at 175 °C, 200 °C, 225 °C, and 250 °C in the embodiments of this invention. In contrast, the original MgH2 requires 35 min to absorb 5.1 wt% H2 at 225 °C and approaches saturation within 25 min at 250 °C. This indicates that the reaction rate is significantly higher than that of MgH2 + 10 wt% NiO@Mo. 4 / 3 B2-MBene is slower and requires a higher temperature to achieve effective hydrogen absorption.

[0037] Figure 19 In this embodiment of the invention, MgH2 + 10 wt% NiO@Mo 4 / 3 The cycling performance image of B2-MBene shows that the activation process is basically completed within the first three cycles, and the hydrogen desorption capacity reaches its maximum of 6.3 wt% in the fourth cycle. After 50 consecutive hydrogen adsorption / desorption cycles, the hydrogen storage capacity of this magnesium-based hydrogen storage material remains at 6.1 wt%, approximately 95.8% of the peak capacity, demonstrating excellent cycling stability. This result indicates that NiO@Mo 4 / 3 The introduction of B2-MBene catalyst can significantly improve the reversible hydrogen absorption and desorption performance and cycle retention rate of MgH2.

[0038] Figure 20 In this embodiment of the invention, MgH2 + 10 wt% NiO@Mo 4 / 3 XRD patterns of B2-MBene hydrogen storage material after ball milling, after 5 hydrogen release cycles, and after 5 hydrogen absorption cycles, showing the synthesized MgH2 + 10 wt%NiO@Mo 4 / 3 B2-MBene is mainly composed of MgH2, NiO, and Mo. 4 / 3The sample was composed of a B2-MBene phase. Furthermore, during hydrogen adsorption and desorption, a diffraction peak at a scattering angle of 43.2° was observed, attributing to MgO. The trace amounts of MgO detected in the sample likely originated from the surface oxidation of MgH2 during ball milling and sample preparation. A reversible transition occurred between Mg and MgH2 during hydrogen adsorption and desorption. Simultaneously, Mg2Ni was detected after the 5th hydrogen desorption, and Mg2NiH4 was detected after the 5th re-hydrogen adsorption. This indicates that some NiO reacted with MgH2 to form Mg2Ni during hydrogen desorption and then transformed into Mg2NiH4 during re-hydrogen adsorption. The Mg2NiH4 phase exhibits excellent hydrogen dissociation and adsorption capabilities, acting as a highly efficient "hydrogen pump," weakening the Mg-H bond energy, providing a channel for rapid H atom migration, and accelerating H atom adsorption and desorption. After 5 hydrogen adsorption and desorption cycles, the final composition was MgH2 + 10 wt% NiO@Mo. 4 / 3 B2-MBene maintained a stable phase composition after multiple hydrogen adsorption and desorption cycles, demonstrating good cycling stability.

[0039] To further study MgH2 + 10 wt%NiO@Mo 4 / 3 The microstructure evolution of B2-MBene during ball milling and subsequent hydrogen adsorption / desorption cycles was further analyzed using transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and selected area electron diffraction (SAED). Figure 21 In this embodiment of the invention, MgH2 + 10 wt% NiO@Mo 4 / 3 TEM and HRTEM images of the B2-MBene hydrogen storage material after hydrogen absorption show that the catalyst and MgH2 are uniformly dispersed after hydrogen absorption, and no aggregation was observed. Further observation was conducted on MgH2 + 10 wt% NiO@Mo... 4 / 3 HRTEM images of B2-MBene reveal the interplanar spacing values ​​corresponding to different crystal planes. Interplanar spacing measurements were performed on selected regions, where interplanar spacings of 0.269 nm and 0.219 nm corresponded to (Mo... 2 / 3 Y 1 / 3 The (110) and (116) crystal planes of Mg2AlB2-MAB match, and the 0.209 nm interplanar spacing is consistent with the (200) crystal plane of NiO. Furthermore, the newly emerging 0.228 nm interplanar spacing corresponds to the (220) crystal plane of Mg2NiH4, while the 0.256 nm and 0.224 nm interplanar spacings belong to the (101) and (200) crystal planes of MgH2, respectively. These observations indicate that during mechanical ball milling, NiO@Mo 4 / 3 B2-MBene is well dispersed in the MgH2 matrix, forming a rich and interconnected multiphase interface. This magnesium-based hydrogen storage material contains a large amount of MgH2 / NiO / Mo.4 / 3 B2-MBene phase boundaries, which serve as preferential channels for hydrogen transport, play a crucial role in the observed improvement in hydrogen storage performance through their synergistic effect. Figure 22 In this embodiment of the invention, MgH2 + 10wt%NiO@Mo 4 / 3 SAED images of the B2-MBene hydrogen storage material after hydrogen absorption show a clear set of polycrystalline diffraction ring patterns, which correspond to (Mo) 2 / 3 Y 1 / 3 (110) crystal plane of AlB2-MAB crystal, (200) crystal plane of NiO crystal, (200) crystal plane of MgH2 crystal and (422) crystal plane of Mg2NiH4.

[0040] To verify NiO@Mo 4 / 3 XPS analysis was performed on the valence state evolution of B2-MBene during the reaction process, and on magnesium-based hydrogen storage materials after ball milling, hydrogen absorption, and hydrogen release. Figure 23 In this embodiment of the invention, MgH2 + 10 wt% NiO@Mo 4 / 3 The Ni 2p XPS spectra of B2-MBene hydrogen storage material after ball milling, hydrogen release, and hydrogen absorption show that the signal peaks with binding energies at 870.8 eV and 853.1 eV correspond to Ni, respectively. 2+ 2p 1 / 2 and 2p 3 / 2 The electron spin orbitals, with signal peaks at 869.2 eV and 851.7 eV, are attributed to Ni, respectively. 0 2p 1 / 2 and 2p 3 / 2 Electron spin orbitals are represented, while the signal peaks at 861.8 eV and 878.7 eV are attributed to satellite peaks. NiO in MgH2 + 10 wt%NiO@Mo 4 / 3 B2-MBene was consistently present in the sample, and during repeated hydrogen absorption and desorption, some NiO underwent a reduction reaction with MgH2, generating a small amount of Ni. 0 This further confirmed the presence of Mg2Ni and Mg2NiH4, consistent with the XRD analysis results. The aforementioned phases remained stable during mechanical ball milling and hydrogen absorption / desorption processes. Figure 24 In this embodiment of the invention, MgH2 + 10 wt% NiO@Mo 4 / 3 The Mo 3d XPS spectra of B2-MBene hydrogen storage material after ball milling, hydrogen release, and hydrogen absorption show that the orbital peaks at 238.2 / 241.2 eV, 236.2 / 239.3 eV, 231.0 / 237.5 eV, and 227.5 / 234.2 eV are attributed to Mo. 4 / Mo in 3B2-MBene6+ Mo 5+ Mo 4+ And Mo-B-Tz. Figure 25 In this embodiment of the invention, MgH2 + 10 wt% NiO@Mo 4 / XPS spectra of B1s in 3B2-MBene hydrogen storage material after ball milling, hydrogen desorption, and hydrogen absorption. The XPS spectrum of B1s shows two signal peaks at 185.7 eV and 192.9 eV, which are attributed to the Mo-B-Tz and BO bonds, respectively. The BO bond originates from the slight oxidation of B during HF treatment. The chemical states of B1s and Mo3d after hydrogen absorption and desorption did not change significantly compared to those after ball milling. The presence of multivalent Mo species is beneficial to Mg. 2+ With H - The charge transfer between them helps to enhance catalytic activity.

[0041] Apparent activation energy ( E a) is a key indicator for evaluating catalytic performance. Figure 26 In the embodiments of the present invention, ln[-ln(1-] is pure MgH2. α )] and ln t Relationship curve Figure 27 In this embodiment of the invention, MgH2 + 10 wt% NiO@Mo 4 / 3 B2-MBene hydrogen storage material ln[-ln(1- α )] and ln t Relationship curve. This study is based on MgH2 and MgH2 + 10 wt% NiO@Mo. 4 / 3 Isothermal dehydrogenation experimental data of B2-MBene were used to construct ln[-ln(1- α )] for ln t A relationship diagram was created to reveal the dehydrogenation kinetics of different systems. Furthermore, the kinetic model was combined with the Arrhenius equation to plot the Arrhenius diagram, and the apparent activation energy of different systems was calculated based on the slope of the fitted linear curve. Figure 28 The Arrhenius curve for pure MgH2 in this embodiment of the invention is shown. The apparent activation energy of pure MgH2 is 133.89 ± 7.72 kJ·mol⁻¹. -1 , Figure 29 In this embodiment of the invention, MgH2 + 10 wt% NiO@Mo 4 / 3 Arrhenius curve of B2-MBene hydrogen storage material, MgH2 + 10 wt%NiO@Mo 4 / The apparent activation energy for the dehydrogenation of 3B2-MBene was significantly reduced to 98.81 ± 3.86 kJ·mol⁻¹.-1 The decrease reached 25.9%, and the correlation coefficient was [missing information]. R 2 All values ​​are greater than 0.99. This result indicates that NiO@Mo 4 / 3 The introduction of B2-MBene significantly reduced the activation energy of the dehydrogenation reaction. This performance improvement is mainly attributed to Mo. 4 / 3 The nanosheet structure of B2-MBene provides a large contact area, offering more active sites for H2 adsorption and dissociation, while also improving the dispersibility of NiO. Furthermore, Mo... 4 / 3 The synergistic effect between B2-MBene and NiO significantly lowers the energy barrier for the dehydrogenation reaction.

[0042] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0043] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A layered transition metal molybdenum boride (NiO@Mo) supported on nickel oxide 4 / 3 B2-MBene-modified magnesium-based hydrogen storage material and its preparation method, characterized in that, The magnesium-based hydrogen storage material uses MgH2 as the matrix material and NiO@Mo as the substrate material. 4 / 3 B2-MBene is the modifier, and the NiO@Mo 4 / 3 B2-MBene is a NiO nanoparticle loaded with Mo. 4 / 3 The structure on B2-MBene nanosheets, in which Mo 4 / 3 B2-MBene has ordered molybdenum vacancy defects with an interlayer spacing of 10.39 Å.

2. The magnesium-based hydrogen storage material according to claim 1, characterized in that, The NiO@Mo 4 / 3 The mass of B2-MBene is 1% to 30% of the total mass of the magnesium-based hydrogen storage material.

3. The magnesium-based hydrogen storage material according to claim 2, characterized in that, The NiO@Mo 4 / 3 The preferred mass of B2-MBene is 10% of the total mass of the magnesium-based hydrogen storage material.

4. A method for preparing the magnesium-based hydrogen storage material as described in any one of claims 1 to 3, characterized in that, Includes the following steps: (1) Preparation of layered Mo 4 / 3 B2-MBene: with (Mo 2 / 3 Y 1 / 3 Using 2AlB2-MAB as a precursor, aluminum and yttrium atoms were selectively etched away with hydrofluoric acid solution. After centrifugation to remove impurities, intercalation and layering were performed. The colloidal supernatant was collected and vacuum dried to obtain layered Mo. 4 / 3 B2-MBene powder; (2) Preparation of NiO@Mo 4 / 3 B2-MBene: in the form of layered Mo 4 / 3 Using B2-MBene powder as the matrix material, Ni(NO3)2·6H2O as the nickel source and urea as the precipitant were used for uniform stirring. NaOH solution was then added dropwise to adjust the pH to 10, and stirring continued. The mixed solution was then transferred to a high-pressure reactor for hydrothermal reaction. After the reaction, the solution was centrifuged to remove impurities, and the resulting precipitate was dried in a vacuum drying oven. Finally, the precursor was calcined in a muffle furnace to obtain NiO@Mo. 4 / 3 B2-MBene powder; (3) Preparation of magnesium-based hydrogen storage materials: NiO@Mo 4 / 3 B2-MBene powder and MgH2 were weighed according to a stoichiometric ratio and subjected to high-energy mechanical ball milling under an inert atmosphere to obtain the magnesium-based hydrogen storage material, i.e., the material with added NiO@Mo. 4 / 3 B2-MBene magnesium-based hydrogen storage material.

5. The preparation method according to claim 4, characterized in that, In step (1), the mass concentration of the hydrofluoric acid solution is 40%, (Mo 2 / 3 Y 1 / 3 The ratio of AlB2-MAB powder to hydrofluoric acid solution was 1 g: 25 mL; the selective etching conditions were 0–100 °C with magnetic stirring for 1–60 h; the centrifugation speed was 1000–10000 r / min; and the supernatant was washed 6 times alternately with alcohol and deionized water until it was neutral.

6. The preparation method according to claim 4, characterized in that, In step (1), the intercalation and layering process involves dispersing the centrifuged precipitate in a 1%–20% tetramethylammonium hydroxide (TMAOH) solution and then performing an ultrasonic-assisted intercalation and layering process; the vacuum drying conditions are drying at 60 °C for 6 h.

7. The preparation method according to claim 4, characterized in that, In step (2), the Mo 4 / 3 The molar ratio of B2-MBene, Ni(NO3)2·6H2O, and urea is 1:1:1; the concentration of the NaOH solution is 1.0 mol·L⁻¹. -1 The hydrothermal reaction conditions were: holding at 150 °C for 12 h; the vacuum drying conditions were: drying at 60 °C for 6 h; and the muffle furnace calcination conditions were: calcination at 3 °C / min. -1 The heating rate was increased to 300 °C and held at that temperature for 2.5 h.

8. The preparation method according to claim 4, characterized in that, In step (3), the inert atmosphere is high-purity argon, and the O2 content is ≤0.1 ppm and the H2O content is ≤0.1 ppm under the argon atmosphere; the mechanical ball milling adopts a high-energy ball mill, the ball milling speed is 100~800 r / min, the ball milling time is 1~50 h, the ball-to-material ratio is 50:1, and the ball milling process is paused for 5 min every 15 min.

9. The NiO@Mo according to claim 1 or 2 4 / 3 The application of B2-MBene modified magnesium-based hydrogen storage materials in the field of solid-state hydrogen energy storage is characterized by, It is applied to solid-state hydrogen storage scenarios such as hydrogen energy storage and transportation and fuel cell hydrogen supply.

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