阅读说明：本技术 由稀土氧化物和纳米硼镍包裹的镁基储氢材料的制备方法 (Preparation method of magnesium-based hydrogen storage material coated by rare earth oxide and nano nickel-boron ) 是由 刘宾虹 高子钧 李洲鹏 于 2020-12-09 设计创作，主要内容包括：本发明涉及金属材料储氢技术,旨在提供一种由稀土氧化物和纳米硼镍包裹的镁基储氢材料的制备方法。包括：将硼氢化钠碱液滴加于含稀土和镍的混合溶液中,镍被还原形成纳米非晶硼镍,同时碱液使溶液pH值上升导致产生稀土氢氧化物胶状沉淀,进而形成纳米非晶硼镍掺杂的稀土氢氧化物凝胶体；真空干燥处理凝胶体,并经高温干燥脱水后,得到稀土氧化物担载纳米硼镍复合材料；将其与镁氢化物混合球磨,镁氢化物脱氢成为金属镁,进而得到产品。本发明避免了形成镁镍合金,稀土氧化物保持稳定存在从而保持性能的稳定。有利于降低放氢温度,提高放氢速度。降低稀土镁合金吸氢温度,加快吸氢速度。能作为大容量储氢介质,用于制造商业化应用的便携式电源。(The invention relates to a metal material hydrogen storage technology, and aims to provide a preparation method of a magnesium-based hydrogen storage material coated by rare earth oxide and nano nickel-boron. The method comprises the following steps: dropping sodium borohydride alkali solution into a mixed solution containing rare earth and nickel, reducing the nickel to form nano amorphous boron-nickel, and simultaneously raising the pH value of the solution by using the alkali solution to generate rare earth hydroxide colloidal precipitate so as to form nano amorphous boron-nickel doped rare earth hydroxide gel; drying the gel in vacuum, and drying and dehydrating at high temperature to obtain the rare earth oxide supported nano boron-nickel composite material; mixing it with magnesium hydride, ball-milling, dehydrogenating to obtain magnesium metal, and further obtaining the product. The invention avoids forming magnesium-nickel alloy, and the rare earth oxide keeps stable existence, thereby keeping stable performance. Is favorable for reducing the hydrogen release temperature and improving the hydrogen release speed. The hydrogen absorption temperature of the rare earth magnesium alloy is reduced, and the hydrogen absorption speed is accelerated. Can be used as a large-capacity hydrogen storage medium for manufacturing a portable power supply for commercial application.)

1. A preparation method of magnesium-based hydrogen storage material coated by rare earth oxide and nano nickel-boron is characterized by comprising the following steps:

(1) dissolving nickel nitrate and rare earth nitrate into deionized water according to the mol ratio of 1: 0.5-1.5: 100 to form a mixed solution containing rare earth and nickel;

(2) weighing sodium borohydride according to the molar ratio of 1: 0.25-0.5 of nickel nitrate to sodium borohydride, and dissolving the sodium borohydride in a 10% NaOH solution to obtain sodium borohydride alkali liquor; wherein the mass percentage concentration of the sodium borohydride is 2-5%;

(3) dropwise adding sodium borohydride alkali liquid into the mixed solution containing rare earth and nickel obtained in the step (1), reducing the nickel to form nano amorphous boron-nickel, and simultaneously raising the pH value of the solution by using alkali liquid to generate rare earth hydroxide colloidal precipitate so as to form nano amorphous boron-nickel doped rare earth hydroxide gel; drying the gel in vacuum to obtain the rare earth hydroxide and nano nickel-boron composite material; drying and dehydrating at 300-400 ℃ to obtain the rare earth oxide supported nano boron-nickel composite material;

(4) weighing the magnesium hydride and rare earth oxide supported nano boron-nickel composite material according to the mass ratio of 1: 0.03-0.1, and mixing and ball-milling for 5-12 h; in the process, the magnesium hydride is dehydrogenated into metal magnesium, and then the magnesium-based hydrogen storage material coated by rare earth oxide and nano nickel-boron is obtained.

2. The method according to claim 1, wherein the rare earth nitrate is lanthanum nitrate or cerium nitrate, or a mixed rare earth nitric acid solution with La and Ce as main components.

3. The method according to claim 2, wherein the rare earth nitrate is obtained by dissolving lanthanum metal or cerium metal in a nitric acid solution; the mixed rare earth nitric acid solution is obtained by dissolving mixed rare earth oxide in nitric acid solution or by mixing different rare earth nitric acid solutions.

Technical Field

The invention relates to a metal material hydrogen storage technology, in particular to a preparation method of a magnesium-based hydrogen storage material modified by rare earth oxide, amorphous nano boron-nickel and Grignard reagent.

Background

Hydrogen energy is clean, environment-friendly and renewable, and is considered as the most ideal secondary energy in the 21 st century, and the technology of fuel cells (PEMFCs) with proton exchange membranes as electrolytes is mature day by day. Hydrogen gas, which is a fuel for fuel cells, is stored in two major categories, physical and chemical. The physical method mainly comprises the following steps: liquid hydrogen storage, high pressure hydrogen storage, glass microsphere storage, underground cavern storage, activated carbon adsorption storage, carbon nanotube storage (including partial chemisorption storage as well). The chemical method mainly comprises the following steps: metal hydride storage, organic liquid hydride storage, inorganic storage, and the like.

The metal hydrogen storage alloy has strong capability of capturing hydrogen, hydrogen molecules can be decomposed into single atoms on the surface of the alloy under certain temperature and pressure conditions, the single atoms and the alloy are subjected to chemical reaction to generate metal hydride, and the metal hydride is externally expressed as a large amount of hydrogen absorbed and heat is released at the same time. When these metal hydrides are heated, they undergo decomposition reaction, and hydrogen atoms can be combined into hydrogen molecules to be released, and the hydrogen molecules are accompanied by obvious endothermic effect. The hydrogen storage alloy is adopted to store hydrogen, so that the energy consumption is low, the working pressure is low, the use is convenient, and a huge steel container can be omitted, so that the storage and the transportation are convenient and safe. The existing hydrogen storage alloy mainly comprises titanium-series, zirconium-series, magnesium-series and rare earth-series hydrogen storage alloys, wherein metal magnesium has high hydrogen storage density of 7.6 wt%, can realize reversible hydrogen absorption and desorption, has high storage and transportation efficiency, abundant resources and low price, and is an ideal hydrogen storage material.

Since magnesium metal is relatively active, the surface of magnesium metal is usually covered by a dense oxide film. Although the compact oxide film prevents the magnesium metal from being further oxidized, the surface protection effect is achieved, the hydrogen permeability is also hindered, the activation is difficult, the hydrogen absorption and desorption speed of the magnesium metal is low, the actual hydrogen absorption and desorption temperature is high, and the practical process of the magnesium metal is seriously hindered. The method for improving the hydrogen absorption and desorption performance of magnesium mainly comprises the following steps: one is alloying, and the hydrogen absorption and desorption reaction is catalyzed by adding an alloy element, but the alloy density is increased, and the hydrogen storage capacity is reduced. And secondly, surface treatment, namely forming a surface protective layer which is easy to permeate hydrogen and blocks oxygen by eliminating a compact magnesium oxide film, thereby improving the hydrogen absorption and desorption speed performance under the condition of not changing the hydrogen storage density of magnesium.

Disclosure of Invention

The invention aims to solve the technical problem of overcoming the defects in the prior art and provides a magnesium-based hydrogen storage material consisting of a rare earth oxide cocatalyst and a nano boron-nickel amorphous catalyst and a preparation method thereof.

In order to solve the technical problem, the solution of the invention is as follows:

the preparation method of the magnesium-based hydrogen storage material coated by the rare earth oxide and the nano nickel-boron is provided, and comprises the following steps:

(1) dissolving nickel nitrate and rare earth nitrate into deionized water according to the mol ratio of 1: 0.5-1.5: 100 to form a mixed solution containing rare earth and nickel;

(2) weighing sodium borohydride according to the molar ratio of 1: 0.25-0.5 of nickel nitrate to sodium borohydride, and dissolving the sodium borohydride in a 10% NaOH solution to obtain sodium borohydride alkali liquor; wherein the mass percentage concentration of the sodium borohydride is 2-5%;

(3) dropwise adding sodium borohydride alkali liquid into the mixed solution containing rare earth and nickel obtained in the step (1), reducing the nickel to form nano amorphous boron-nickel, and simultaneously raising the pH value of the solution by using alkali liquid to generate rare earth hydroxide colloidal precipitate so as to form nano amorphous boron-nickel doped rare earth hydroxide gel; drying the gel in vacuum to obtain the rare earth hydroxide and nano nickel-boron composite material; drying and dehydrating at 300-400 ℃ to obtain the rare earth oxide supported nano boron-nickel composite material;

(4) weighing magnesium hydride (MgH) according to the mass ratio of 1: 0.03-0.1₂) And rare earth oxide supported nanometer boron-nickel composite material, and mixing and ball milling for 5-12 h; in the process, the magnesium hydride is dehydrogenatedBecomes metal magnesium, and further obtains the magnesium-based hydrogen storage material coated by rare earth oxide and nano nickel-boron.

In the invention, the rare earth nitrate is lanthanum nitrate or cerium nitrate, or mixed rare earth nitric acid solution taking La and Ce as main components (such as lanthanum-rich mixed rare earth Ml or cerium-rich mixed rare earth Mm, the molecular weight is calculated by 140g, and the mixed rare earth can also contain a certain amount of praseodymium Pr and neodymium Nd).

In the invention, the rare earth nitrate is obtained by dissolving lanthanum metal or cerium metal in a nitric acid solution; the mixed rare earth nitric acid solution is obtained by dissolving mixed rare earth oxide in nitric acid solution or by mixing different rare earth nitric acid solutions.

Description of the inventive principles:

the invention relates to a surface modified magnesium-based hydrogen storage material for synthesizing rare earth oxide and a nano boron-nickel amorphous catalyst, which is prepared by reacting chlorobenzene with magnesium metal to form a Grignard reagent on the basis of ball milling magnesium hydride and the amorphous catalyst to form a multifunctional surface layer based on rare earth oxide as a stabilizer and nano boron-nickel as a hydrogen absorption and desorption catalytic site, and effectively improves the hydrogen absorption and desorption kinetics of the magnesium metal.

Hydrogen molecules are cracked and adsorbed on the amorphous catalyst nano boron-nickel to form hydrogen atoms. After the cracking adsorption of hydrogen molecules reaches balance, hydrogen atoms are quickly separated from the nano nickel-boron due to the existence of the rare earth oxide, so that the hydrogen molecule cracking adsorption balance is favorably moved to the direction of forming the hydrogen atoms. The rare earth oxide belongs to a hole-shaped semiconductor, is positively charged, forms a strong dipole pair with phenyl anions on the phenylmagnesium chloride, and is favorable for transferring electrons of the phenyl anions on the phenylmagnesium chloride to hydrogen atoms to form hydride anions to generate magnesium hydride (MgH)₂) Thus, the dipolar pair of Grignard reagent phenylmagnesium chloride and rare earth oxide facilitates the hydrogenation of magnesium to form MgH₂. On one hand, the rare earth oxide assists hydrogen atoms to diffuse, on the other hand, the rare earth oxide also assists the hydrogen atoms to be converted into hydride, and the remarkable catalysis assisting effect is shown. And chloride ion (Cl) contained in phenylmagnesium chloride^-) Albeit than MgH₂Hydrogen anion (H) of (1)^-) Slightly larger radius, in phenylmagnesium chloride and MgH₂Interface Cl^-And H^-Interchange of positions is possible, however Cl^-And H^-Is completely different, the hydride ions lose electrons more easily than the chloride ions. In the process of hydrogen evolution, MgH₂Hydrogen anion of (1) H^-The hydrogen atoms are formed on the amorphous catalyst nano boron-nickel due to the fact that the concentration of the hydrogen atoms in the adsorption balance is increased, so that the hydrogen molecule cracking adsorption balance moves towards the reverse reaction direction, the hydrogen atoms are coupled to form hydrogen molecules, and therefore the rare earth oxide can also help to catalyze MgH₂To discharge hydrogen.

Compared with the prior art, the invention has the beneficial effects that:

1. in the invention, the catalytic center (nano boron nickel) and the magnesium metal are isolated by the rare earth oxide, so that magnesium nickel alloy is prevented from being formed in the material synthesis process and the hydrogen absorption and desorption process of the magnesium metal, and the rare earth oxide stably exists, thereby keeping the stability of performance.

2. If no rare earth oxide coexists in the ball milling process, the metal magnesium easily forms alloy Mg with the nano boron-nickel₂Ni, causing performance degradation. According to the invention, the catalytic sites based on amorphous catalyst nano boron-nickel and Grignard reagent are formed on the surface of the magnesium-gold by surface modification, so that the activation energy of the hydrogen desorption reaction of metal magnesium is reduced, the hydrogen desorption temperature is reduced, and the hydrogen desorption speed is increased. A Grignard reagent phenylmagnesium chloride is formed on the surface of the magnesium-based alloy to form a strong dipole pair with rare earth oxide to promote the formation of hydrogen anions, which is favorable for further reducing the activation energy of the magnesium hydrogen absorption reaction, reducing the hydrogen absorption temperature of the rare earth magnesium alloy and accelerating the hydrogen absorption speed.

3. The magnesium metal modified by rare earth oxide, amorphous nano boron-nickel and Grignard reagent has extremely high hydrogen storage capacity and hydrogen absorption and desorption dynamic performance, is used as a high-capacity hydrogen storage medium to provide pure hydrogen for fuel cells, can be manufactured into portable and mobile power sources for large-scale commercial application, and is applied to electric automobiles, electronic products, military equipment and the like.

Drawings

FIG. 1 is a comparison of hydrogen absorption curves of Mg-based hydrogen storage material coated with Grignard reagent in-situ modified Ce-rich rare earth oxide and nano B-Ni composite material of the invention obtained in example 10 and magnesium metal.

FIG. 2 shows MgH, a Mg-based hydrogen storage material coated with a Grignard reagent in-situ modified lanthanum-rich rare earth oxide and a nano boron-nickel composite material of the invention obtained in example 11₂Compared with the hydrogen absorption and desorption cycle performance of the ball-milling material of nano nickel-boron.

The reference numbers in the figures are: 1-1 hydrogen absorption and heating temperature curve, 1-2 hydrogen absorption curve of magnesium-based hydrogen storage material wrapped by Grignard reagent in-situ modified cerium-rich rare earth oxide and nano boron-nickel composite material, 1-3 hydrogen absorption curve of metal magnesium powder from market, 2-1 hydrogen absorption and desorption cycle performance of magnesium-based hydrogen storage material wrapped by Grignard reagent in-situ modified lanthanum-rich rare earth oxide and nano boron-nickel composite material, 2-2MgH₂The hydrogen absorption and desorption cycle performance of the ball-milling material with nano nickel boron.

Detailed Description

The present invention will be described in detail below.

Example 1: preparation of mixed nitrate solution

1 mol of nickel nitrate and 0.5 mol of lanthanum nitrate are dissolved in 1.8 liters of deionized water according to the molar ratio of 1: 0.5: 100 to form a nitrate solution of nickel and lanthanum.

Example 2: formation of nano amorphous boron nickel

1 mol of nickel nitrate and 1 mol of cerium nitrate are dissolved in 1.8 liters of deionized water according to the molar ratio of 1: 100 to form a nitrate solution of nickel and cerium. 0.25 mole of sodium borohydride (9.45g) was dissolved in 463.05g of 10 wt% NaOH solution to give an alkali solution containing 2 wt% of sodium borohydride. And dropwise adding sodium borohydride alkali liquid into nitrate solution of nickel and cerium, and reducing the nickel in the solution to form the nano amorphous nickel-boron.

Example 3: preparation of nano amorphous boron-nickel doped lanthanum hydroxide gel

1 mol of nickel nitrate and 1 mol of lanthanum nitrate are dissolved in 1.8 liters of deionized water according to the molar ratio of 1: 1.5: 100 to form a nitrate solution of nickel and lanthanum. 0.4 mol of sodium borohydride (15.12g) was dissolved in 488.88g of 10 wt% NaOH solution to obtain an alkali solution containing 3 wt% of sodium borohydride. And dropwise adding sodium borohydride alkali solution into the nitrate solution of nickel and lanthanum, reducing the nickel in the solution to form nano amorphous boron-nickel, and simultaneously, dropwise adding alkali solution to cause the pH value of the solution to rise to cause colloidal precipitation of lanthanum hydroxide to form nano amorphous boron-nickel doped lanthanum hydroxide gel.

Example 4: preparation of cerium hydroxide and nano boron-nickel composite material

1 mol of nickel nitrate and 1 mol of cerium nitrate are dissolved in 1.8 liters of deionized water according to the mol ratio of 1: 1.5: 100 to form a nitrate solution of nickel and cerium. 0.5 mol of sodium borohydride (18.9g) was dissolved in 359.1g of 10 wt% NaOH solution to obtain an alkali solution containing 5 wt% of sodium borohydride. And dropwise adding sodium borohydride alkali solution into the nitrate solution of nickel and cerium, reducing the nickel in the solution to form nano amorphous boron-nickel, and simultaneously, increasing the pH value of the solution by the dropwise added alkali solution to cause colloidal precipitation of cerium hydroxide to form nano amorphous boron-nickel doped cerium hydroxide gel. And drying in vacuum to obtain the composite material of cerium hydroxide and nano nickel-boron.

Example 5: preparation of lanthanum-rich mixed rare earth nitric acid solution

Lanthanum-rich rare earth oxide (Ml) from vendors₂O₃) Dissolving in 10 wt% nitric acid, and collecting the supernatant to obtain the lanthanum-rich mixed rare earth nitric acid solution.

Example 6: preparation of cerium-rich mixed rare earth nitric acid solution

0.8 mol of cerous nitrate hexahydrate and (347.37g) of vendor and 0.2 mol of lanthanum nitrate hexahydrate are dissolved in 1.8 liters of deionized water to form a lanthanum-containing cerium-rich mixed rare earth nitric acid solution.

Example 7: preparation of cerium-rich rare earth oxide and nano boron-nickel composite material

Taking 1 mol cerium-rich rare earth oxide (328g Mm)₂O₃) Dissolved in 20 wt% nitric acid (1030g), and the supernatant was taken to obtain a cerium-rich mixed rare earth nitric acid solution.

According to the molar ratio of 1: 1 of nickel nitrate and cerium-rich mixed rare earth, 1 mol of nickel nitrate is dissolved in the cerium-rich mixed rare earth nitric acid solution to form a nitrate solution of nickel and mixed rare earth.

0.5 mol of sodium borohydride (18.9g) was dissolved in 359.1g of 10 wt% NaOH solution to obtain an alkali solution containing 5 wt% of sodium borohydride. And dropwise adding sodium borohydride alkali solution to the nitrate solution, reducing nickel in the solution to form nano amorphous boron-nickel, and simultaneously, increasing the pH value of the solution by the dropwise added alkali solution to cause the colloidal mixed rare earth hydroxide to precipitate to form the nano amorphous boron-nickel doped mixed rare earth hydroxide gel. Vacuum drying to obtain the composite material of mixed rare earth hydroxide and nano nickel-boron, and drying and dehydrating at 300 ℃ to obtain the composite material of cerium-rich rare earth oxide and nano nickel-boron.

Example 8: preparation of magnesium-based hydrogen storage material wrapped by lanthanum-rich rare earth oxide and nano boron-nickel composite material

Taking 1 mol lanthanum-rich rare earth oxide (328g Ml) from vendor₂O₃) Dissolved in 20 wt% nitric acid (1030g), and the supernatant was taken to obtain a lanthanum-rich mixed rare earth nitric acid solution.

According to the molar ratio of 1: 1 of nickel nitrate and lanthanum-rich mixed rare earth, 1 mol of nickel nitrate is dissolved in the lanthanum-rich mixed rare earth nitric acid solution to form a nitrate solution of nickel and mixed rare earth.

0.5 mol of sodium borohydride (18.9g) was dissolved in 359.1g of 10 wt% NaOH solution to obtain an alkali solution containing 5 wt% of sodium borohydride. And dropwise adding sodium borohydride alkali solution to the nitrate solution, reducing nickel in the solution to form nano amorphous boron-nickel, and simultaneously, increasing the pH value of the solution by the dropwise added alkali solution to cause the colloidal mixed rare earth hydroxide to precipitate to form the nano amorphous boron-nickel doped mixed rare earth hydroxide gel. Vacuum drying to obtain the composite material of mixed rare earth hydroxide and nano nickel-boron, and drying and dehydrating at 350 ℃ to obtain the composite material of lanthanum-rich rare earth oxide and nano nickel-boron.

Weighing magnesium hydride (MgH) in a mass ratio of 1: 0.03₂) Ball milling the composite material of the lanthanum-rich rare earth oxide and the nano boron nickel for 5 hours, and dehydrogenating magnesium hydride to obtain metal magnesium; obtaining the magnesium-based hydrogen storage material wrapped by the lanthanum-rich rare earth oxide and the nano boron-nickel composite material.

Example 9: grignard reagent in situ modification

0.5 mole of sodium borohydride (18.9g) is dissolved in 359.1g of 10 wt% NaOH solution to obtain alkali solution containing 5 wt% of sodium borohydride, the sodium borohydride alkali solution is dripped into the nitrate solution of nickel and lanthanum obtained in example 1, nickel in the solution is reduced to form nano amorphous boron-nickel, and simultaneously the dripped alkali solution causes the pH value of the solution to rise to cause colloidal lanthanum hydroxide to precipitate, so that nano amorphous boron-nickel doped lanthanum hydroxide gel is formed. Vacuum drying to obtain the composite material of lanthanum hydroxide and nano nickel-boron, and drying and dehydrating at 400 ℃ to obtain the composite material of lanthanum oxide and nano nickel-boron.

Weighing magnesium hydride (MgH) in a mass ratio of 1: 0.06₂) Ball milling the composite material of the lanthanum-rich rare earth oxide and the nano nickel-boron for 9 hours, and dehydrogenating magnesium hydride to obtain metal magnesium; obtaining the magnesium-based hydrogen storage material wrapped by the lanthanum oxide and nano boron-nickel composite material.

And (2) putting 1g of magnesium-based hydrogen storage material wrapped by the lanthanum oxide and nano nickel-boron composite material into a reactor, dripping 5mL of tetrahydrofuran solution containing 1 wt% of chlorobenzene, connecting the reactor to a hydrogen absorption and desorption test system, heating to 70 ℃, and reacting for 2h to complete the in-situ modification of the Grignard reagent of the magnesium-based hydrogen storage material.

Example 10: hydrogen absorption of surface modified magnesium-based hydrogen storage materials

Weighing magnesium hydride (MgH) in a mass ratio of 1: 0.1₂) And taking the composite material of cerium-rich rare earth oxide and nano boron-nickel obtained in the embodiment 7, ball-milling for 12 hours, and dehydrogenating magnesium hydride to obtain metal magnesium; obtaining the magnesium-based hydrogen storage material wrapped by the cerium-rich rare earth oxide and the nano boron-nickel composite material;

in the invention, the hydrogen absorption and desorption test system is a volumetric test system, namely the pressure change of each cavity with known volume is obtained through testing, and the hydrogen absorption and desorption amount of the material is obtained through calculation according to the mass conservation law and the gas state equation.

And (2) putting 1g of the magnesium-based hydrogen storage material into a reactor, dripping 5mL of tetrahydrofuran solution containing 2.5 wt% of chlorobenzene, connecting the reactor to a hydrogen absorption and desorption test system, heating to 70 ℃, and reacting for 2h to complete the in-situ modification of the Grignard reagent of the magnesium-based hydrogen storage material. Vacuumizing the reactor to 1 Pa at 70 ℃, then filling hydrogen with the purity of 99.999 percent at 40 atmospheric pressure, raising the temperature to 200 ℃ at the speed of 5 ℃/min, and keeping the hydrogen pressure for 3 hours to finish the hydrogenation.

Likewise, magnesium metal is hydrogenated. After the magnesium-based hydrogen storage material wrapped by the cerium-rich rare earth oxide and the nano boron-nickel composite material is subjected to in-situ modification treatment by using the Grignard reagent, the hydrogen absorption performance of the material is shown in figure 1. Compared with metal magnesium sold in markets, the hydrogen absorption temperature is obviously reduced, and the hydrogen absorption speed is obviously improved.

In step (3), MgH₂The magnesium-based hydrogen storage material is converted into metal magnesium by mechanochemical dehydrogenation, and the surface of the metal magnesium is coated by rare earth oxide to obtain the magnesium-based hydrogen storage material coated by the rare earth oxide and the nano boron-nickel composite material. Because rare earth metal ions can not be reduced by sodium borohydride and magnesium metal, the magnesium-nickel alloy is prevented from being formed in the ball milling process and the hydrogen absorption and desorption process of the magnesium metal. In step (4), chlorobenzene reacts with the magnesium metal therein to form the Grignard reagent phenylmagnesium chloride. Through the steps (3) and (4), a composite catalytic mechanism of rare earth oxide containing a cocatalyst, amorphous catalyst nano boron-nickel and phenyl magnesium chloride is formed in the magnesium metal surface layer, and a new catalytic system for magnesium metal hydrogenation and dehydrogenation is formed.

Example 11: hydrogen absorption and desorption circulation of surface modified magnesium-based hydrogen storage material

Taking 1g of the magnesium-based hydrogen storage material wrapped by the lanthanum-rich rare earth oxide and the nano nickel-boron composite material obtained in the embodiment 8, putting the magnesium-based hydrogen storage material into a reactor, dripping 5mL of tetrahydrofuran solution containing 5 wt% of chlorobenzene into the reactor, connecting the reactor to a hydrogen absorption and desorption test system, heating the reactor to 70 ℃, and reacting the reactor for 2 hours to complete the in-situ modification of the Grignard reagent of the magnesium-based hydrogen storage material. Vacuumizing the reactor to 1 pascal at 70 ℃, then filling hydrogen with the purity of 99.999 percent at 40 atmospheric pressure, raising the temperature to 200 ℃ at the speed of 5 ℃/min, and keeping the hydrogen pressure to ensure that the hydrogen storage amount of the material reaches 6.5wt percent; similarly, the magnesium powder of market vendor is hydrogenated to reach the same hydrogen storage amount (6.5 wt%), the temperature is raised to 400 ℃ at the speed of 5 ℃/min, then the hydrogen pressure is maintained at 1 atmosphere to discharge the hydrogen to the atmosphere, and the modified magnesium-based hydrogen storage material, MgH, are subjected to the water discharge and gas collection method₂The hydrogen absorption and desorption cycle performance of the ball-milling material with the nano nickel boron is shown in figure 2. The lanthanum-rich rare earth of the inventionThe magnesium-based hydrogen storage material wrapped by the earth oxide and the nano boron-nickel composite material has good circulation stability, and MgH₂The ball-milling material with nano nickel-boron continuously forms Mg in the process of absorbing and releasing hydrogen₂Ni causes the reduction of surface catalyst sites and the reduction of hydrogen absorption and desorption.

Finally, it should also be noted that the above-mentioned list is only a specific embodiment of the invention. It is obvious that the invention is not limited to the above embodiments, but that many variations are possible. All modifications which can be derived or suggested by a person skilled in the art from the disclosure of the present invention are to be considered within the scope of the invention.