Microporous nickel-rare earth alloy and its preparation method and application

Abstract

The embodiment of the present application discloses a microporous nickel-rare earth alloy and a preparation method and application thereof. The preparation method of the microporous nickel-rare earth alloy comprises the following steps: heating aluminum powder in a vacuum induction furnace to obtain molten aluminum; adding a lanthanum-rich hydrogen storage alloy into the molten aluminum and continuing to heat to obtain an alloy melt; pouring the alloy melt into a mold, cooling to obtain an alloy casting; and placing the alloy casting in a concentrated NaOH solution and filtering under ultrasonic assistance to obtain the microporous nickel-rare earth alloy. The nickel-rare earth alloy provided by the present application has a three-dimensional pore structure with a nanometer-level (tens of nanometers) pore diameter. The structure has a three-dimensional skeleton with good toughness and retains the characteristics of the lanthanum-rich hydrogen storage alloy, thereby greatly improving the hydrogen absorption and desorption cycle times.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of functional materials, and particularly relates to a microporous nickel-rare earth alloy as well as a preparation method and application thereof. BACKGROUND

[0002] Currently, the solid-state storage technology of hydrogen mainly uses nickel-rare earth alloy powder, and uses La-Ni, Ce-Ni, Nd-Ni, Dy-Ni or Ho-Ni alloy. LaNi5 has good hydrogen absorption and desorption performance at 0.3-0.4 MPa room temperature environment, and becomes the only hydrogen storage alloy capable of industrialization. However, the existing lanthanum-nickel alloy hydrogen storage has the problem that the cycle number is difficult to improve, and is easy to be pulverized after multiple hydrogen absorption and desorption. SUMMARY

[0003] In view of the technical defects of the prior art, the present application provides a microporous nickel-rare earth alloy as well as a preparation method and application thereof.

[0004] To achieve the above object, the embodiments of the present application provide the following technical solutions.

[0005] According to a first aspect of the embodiments of the present application, the present application provides a preparation method of a microporous nickel-rare earth alloy, comprising the following steps:

[0006] 1) heating aluminum powder in a vacuum induction furnace to obtain molten aluminum;

[0007] 2) adding a lanthanum-rich hydrogen storage alloy into the molten aluminum and continuing to heat to obtain an alloy melt;

[0008] 3) pouring the alloy melt into a mold and cooling to obtain an alloy casting;

[0009] 4) placing the alloy casting in a concentrated NaOH solution and filtering under ultrasonic assistance to obtain the microporous nickel-rare earth alloy.

[0010] In some preferred embodiments, in step 1), the heating temperature is 750-820℃.

[0011] In some preferred embodiments, in step 2), the mass percentage content of aluminum in the alloy melt is 20-30%.

[0012] In some preferred embodiments, the lanthanum-rich hydrogen storage alloy is M1Ni 3.55 Co 0.75 Mn 0.4 Al 0.3 , wherein M1 is a lanthanum-rich mixed rare earth.

[0013] In some preferred embodiments, in step 4), the concentration of the NaOH solution is 10%-30%.

[0014] In some preferred embodiments, the mass percentage of Al in the microporous nickel-rare earth alloy is 0.4-0.6%. Specifically, the mass percentage of Al in the microporous nickel-rare earth alloy can be achieved by controlling the reaction time of step 4). Generally, the reaction time of step 4) is 20-30 minutes.

[0015] In some preferred embodiments, the method further comprises: introducing CO2 into the filtrate obtained in step 4), filtering, and heating the obtained solid phase to above 175°C to obtain active alumina.

[0016] According to a second aspect of the embodiments of the present application, the present application provides a microporous nickel-rare earth alloy prepared by the method according to any one of the above.

[0017] According to a third aspect of the embodiments of the present application, the present application provides use of the microporous nickel-rare earth alloy according to the above in a hydrogen storage material.

[0018] The embodiments of the present application have the following advantages:

[0019] The nickel-rare earth alloy provided by the present application has a three-dimensional pore structure with nanoscale (tens of nanometers) pore diameter. This structure has a three-dimensional skeleton with good toughness and retains the characteristics of lanthanum-rich hydrogen storage alloy, greatly improving the number of hydrogen absorption and desorption cycles. DETAILED DESCRIPTION

[0020] The embodiments of the present application are described below by specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the disclosure. Obviously, the described embodiments are part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0021] Embodiment 1

[0022] The present embodiment provides a method for preparing a microporous nickel-rare earth alloy, which specifically comprises the following steps:

[0023] Aluminum powder and typical lanthanum-rich hydrogen storage alloy powder are mixed according to a weight ratio of 2:8, wherein the typical lanthanum-rich hydrogen storage alloy is M1Ni 3.55 Co 0.75 Mn 0.4 Al 0.3 (M1 is a lanthanum-rich mixed rare earth);

[0024] The aluminum powder is heated to 800°C in a vacuum induction furnace to become molten aluminum, and then the typical lanthanum-rich hydrogen storage alloy powder is added into the molten aluminum, and the vacuum induction furnace is continuously heated to 1350°C with constant stirring to obtain an alloy melt.

[0025] The alloy melt is poured into a mold. The mold is generally disc-shaped or cylindrical. After cooling, the mold is opened and the alloy castings are taken out. The alloy castings are soaked in a concentrated NaOH solution (30% in concentration) with the assistance of ultrasonic waves. The aluminum in the alloy castings continuously reacts with the NaOH solution to generate sodium metaaluminate. The container for containing the NaOH solution needs to be closed with a cover and a gas outlet, and the hydrogen generated by the reaction is distilled out to a hydrogen gas collecting bottle. The cavitation effect of the ultrasonic waves promotes the precipitation of Al(OH)3 generated by the reaction to separate from the alloy castings, avoiding the blockage of the channels. The reaction is controlled within 20-30 minutes, and the Al component is retained at 0.52%.

[0026] CO2 is introduced into the above solution, and the sodium metaaluminate melt generates Al(OH)3 and NaHCO3. The obtained Al(OH)3 is heated to above 175°C to dehydrate to obtain active aluminum oxide.

[0027] Example 2

[0028] The present embodiment provides a preparation method of a microporous nickel-rare earth alloy, which specifically comprises the following steps:

[0029] The aluminum powder and the typical lanthanum-rich hydrogen storage alloy powder are proportioned according to a weight ratio of 2.5:7.5, wherein the typical lanthanum-rich hydrogen storage alloy is M1Ni 3.55 Co 0.75 Mn 0.4 Al 0.3 (M1 is a lanthanum-rich mixed rare earth);

[0030] The aluminum powder is heated to 780°C in a vacuum induction furnace to become molten aluminum, and then the typical lanthanum-rich hydrogen storage alloy powder is added into the molten aluminum, and the vacuum induction furnace is continuously heated to 1350°C with constant stirring to obtain an alloy melt.

[0031] The alloy melt is poured into a mold. The mold is generally disc-shaped or cylindrical. After cooling, the mold is opened and the alloy castings are taken out. The alloy castings are soaked in a concentrated NaOH solution (20% in concentration) with the assistance of ultrasonic waves. The aluminum in the alloy castings continuously reacts with the NaOH solution to generate sodium metaaluminate. The container for containing the NaOH solution needs to be closed with a cover and a gas outlet, and the hydrogen generated by the reaction is distilled out to a hydrogen gas collecting bottle. The cavitation effect of the ultrasonic waves promotes the precipitation of Al(OH)3 generated by the reaction to separate from the alloy castings, avoiding the blockage of the channels. The reaction is controlled within 20-30 minutes, and the Al component is retained at 0.5%.

[0032] CO2 is introduced into the above solution, and the sodium metaaluminate solution generates Al(OH)3 and NaHCO3. The obtained Al(OH)3 is heated to above 175°C to remove water to obtain active alumina.

[0033] Example 3

[0034] The present example provides a method for preparing a microporous nickel-rare earth alloy, which specifically comprises the following steps:

[0035] Aluminum powder and typical lanthanum-rich hydrogen storage alloy powder are mixed in a weight ratio of 3:7, wherein the typical lanthanum-rich hydrogen storage alloy is M1Ni 3.55 Co 0.75 Mn 0.4 Al 0.3 (M1 is a lanthanum-rich mixed rare earth);

[0036] The aluminum powder is heated to 820°C in a vacuum induction furnace to become molten aluminum, and then the typical lanthanum-rich hydrogen storage alloy powder is added to the molten aluminum. The mixture is continuously heated to 1350°C in the vacuum induction furnace while being stirred to obtain an alloy melt.

[0037] The alloy melt is poured into a mold, which is generally disc-shaped or cylindrical. After cooling, the mold is opened and the alloy casting is taken out. The alloy casting is immersed in a concentrated NaOH solution (25%) with the aid of ultrasonic waves. The aluminum in the alloy casting continuously reacts with the NaOH solution to generate sodium metaaluminate. The container for holding the NaOH solution is closed with a lid, and a distillation outlet is provided. The hydrogen gas generated by the reaction is distilled out of the distillation outlet and into a hydrogen gas collection bottle. The cavitation effect of the ultrasonic waves promotes the precipitation of Al(OH)3 generated by the reaction to separate from the alloy casting, preventing the blockage of the pores. The reaction is controlled to last for 20-30 minutes, and the Al component is retained at 0.45%.

[0038] CO2 is introduced into the above solution, and the sodium metaaluminate solution generates Al(OH)3 and NaHCO3. The obtained Al(OH)3 is heated to above 175°C to remove water to obtain active alumina.

[0039] Test Example 1

[0040] The hydrogen absorption and desorption properties of the microporous nickel-rare earth alloys prepared in Examples 1-3 are tested.

[0041] The results show that after 10 activation cycles in a pure hydrogen tank at a pressure P = 1 MPa and a temperature T = 293 K, the hydrogen absorption amounts of the samples of Examples 1-3 reach 90.2%, 94.5%, and 92.3% of the maximum hydrogen absorption amount of the alloys, respectively.

[0042] Meanwhile, the samples after the cycles are observed by scanning electron microscopy, and the results show that the particle morphology of the samples has not changed substantially.

[0043] The above shows that the microporous nickel-rare earth alloy provided by the embodiment of the application has excellent hydrogen absorption and desorption performance.

[0044] Although the present application has been described in detail with general description and specific embodiments above, some modifications or improvements can be made on the basis of the present application, which is obvious to those skilled in the art. Therefore, these modifications or improvements made on the basis of not deviating from the spirit of the present application, all belong to the scope of the present application claimed.

Claims

1. A method for preparing a microporous nickel rare earth alloy, characterized in that, Includes the following steps: 1) Aluminum powder is heated in a vacuum induction furnace to obtain molten aluminum; 2) Add lanthanum-rich hydrogen storage alloy to the molten aluminum and continue heating to obtain an alloy melt; 3) Pour the molten alloy into a mold, cool it, and obtain an alloy casting; 4) The alloy casting is placed in a 10%-30% NaOH solution and filtered with ultrasonic assistance to obtain the microporous nickel rare earth alloy; The lanthanum-rich hydrogen storage alloy is M1Ni. 3.55 Co 0.75 Mn 0.4 Al 0.3 M1 is a lanthanum-rich mixed rare earth element; The mass percentage of Al in the microporous nickel-rare earth alloy is 0.4-0.6%.

2. The method for preparing microporous nickel-rare earth alloy according to claim 1, characterized in that, In step 1), the heating temperature is 750-820℃.

3. The method for preparing microporous nickel rare earth alloy according to claim 1, characterized in that, In step 2), the mass percentage of aluminum in the alloy melt is 20-30%.

4. The method for preparing microporous nickel rare earth alloy according to claim 1, characterized in that, The method further includes: passing CO2 into the filtrate obtained in step 4), filtering, and heating the obtained solid phase to above 175°C to obtain activated alumina.

5. A microporous nickel rare earth alloy, characterized in that, It is made by the method described in any one of claims 1-4.

6. The application of the microporous nickel rare earth alloy according to claim 5 in hydrogen storage materials.