Nickel-coated aluminum powder with high specific surface area, preparation method and hydrogen production method

Abstract

The invention discloses nickel-coated aluminum powder with high specific surface area, a preparation method and a hydrogen production method, and relates to the technical field of metal powder. Aluminum powder is etched to form porous aluminum powder; loading a conductive nano material to the surface and the pore structure of the porous aluminum powder to obtain modified porous aluminum powder; the preparation method comprises the following steps: uniformly mixing modified porous aluminum powder, a nickel source, a cobalt source and other reagents in a solvent, adjusting the pH value, heating and stirring to form nickel-cobalt-modified porous aluminum powder gel, further drying and calcining, reducing high-valence nickel and high-valence cobalt in the nickel-cobalt-modified porous aluminum powder gel into metal nickel and metal cobalt, coating the modified porous aluminum powder with the metal nickel and the metal cobalt, and drying to obtain the nickel-cobalt-modified porous aluminum powder. The nickel-coated aluminum powder with the high specific surface area is obtained. The nickel-coated aluminum powder prepared by the technical scheme has a porous structure and a very high specific surface area, and a cobalt-containing nickel layer is uniformly coated; the preparation method is simple, the electrical property is excellent, the catalytic performance is very excellent, and the catalyst can be used as a reaction catalyst in the hydrogen production industry.

Description

Technical Field

[0001] This application relates to the technical field of metal powders, and particularly to a nickel-coated aluminum powder with a high specific surface area, a preparation method, and a hydrogen production method. Background Art

[0002] With the continuous increase in global energy demand and the increasingly serious environmental problems, and the demand for high-performance materials in the fields of electronic products, aerospace, chemical catalysis, etc. is also growing day by day. Nickel-based materials are expected to play an important role in these fields due to their unique electrical and thermal properties and good catalytic properties, such as being used to prepare high-conductivity heat dissipation materials, electromagnetic shielding materials, etc. However, pure nickel-based materials often have various disadvantages and are difficult to meet the actual needs.

[0003] The compounding of materials is one of the key strategies to improve performance. Aluminum has high conductivity, high reducibility, rich reserves, and unique physical and chemical properties. Combining it with nickel is expected to construct an innovative new functional material system. By coating nickel on the surface of aluminum powder to form nickel-coated aluminum powder, the catalytic advantages of nickel and the characteristics of aluminum can be combined to further improve the performance of the material.

[0004] However, there are many difficulties in preparing nickel-coated aluminum powder with a high specific surface area. The nickel-coated aluminum powder obtained by conventional coating methods often has particle agglomeration, the uniformity of the nickel layer coating is also insufficient, and it is difficult to further compound other functional materials in the nickel layer, resulting in the powder prepared being unable to fully exert its application value in other fields such as the catalytic and electronics industries.

[0005] Chinese patent application with publication number CN 112264613A discloses a preparation method of nickel-coated aluminum powder for electromagnetic shielding, specifically: first, degrease the aluminum powder; then prepare a dopamine solution, add the aluminum powder, and stir to obtain dopamine-coated aluminum powder; put it into a nickel sulfate hexahydrate solution and continuously stir to make nickel form active sites on the surface of the aluminum powder, wash with water and filter by suction to obtain activated aluminum powder; prepare a sodium hypophosphite solution, and add anhydrous ethanol, anhydrous sodium pyrophosphate, and polyvinylpyrrolidone, add the activated aluminum powder, and finally drop in the nickel sulfate hexahydrate solution to carry out a reduction reaction. During the reaction process, adjust the pH with concentrated ammonia water. After the titration is completed, continue to react for a period of time, wash with water, and dry to obtain nickel-coated aluminum powder.

[0006] Although the above technical solution can obtain nickel-coated aluminum powder with good coating, the preparation process is too complex and the method can still be improved; moreover, the nickel-coated aluminum powder obtained by this technical solution does not have a porous structure and the specific surface area is not high. Summary of the Invention

[0007] In view of the deficiencies of the prior art, the present application provides a nickel-coated aluminum powder with a high specific surface area, a preparation method thereof, and a hydrogen production method. By mixing a conductive nanomaterial, a nickel source, aluminum powder, a solvent, and other reagents evenly under appropriate ratios and addition methods, adjusting the pH, and then heating and stirring to form a nickel-cobalt-modified porous aluminum powder gel, and further drying and calcining, a nickel-coated aluminum powder with a high specific surface area is obtained. The nickel-coated aluminum powder has a very high specific surface area, a uniform cobalt-nickel layer coating, a simple preparation method, excellent electrical properties, and also very excellent catalytic properties, and can be used as a reaction catalyst in the hydrogen production industry.

[0008] To achieve the above object, the present application adopts the following technical solutions: In a first aspect, the present application provides a nickel-coated aluminum powder with a high specific surface area. The nickel-coated aluminum powder includes a modified porous aluminum powder and a cobalt-nickel layer; the cobalt-nickel layer is coated on the pore structure and outer surface of the modified porous aluminum powder; the modified porous aluminum powder includes a porous aluminum powder and a conductive nanomaterial; the conductive nanomaterial is loaded on the pore structure and outer surface of the porous aluminum powder; the conductive nanomaterial includes any one of graphene oxide and carboxylated carbon nanotubes.

[0009] In a second aspect, the present application provides a preparation method of a nickel-coated aluminum powder with a high specific surface area, including: Under nitrogen protection, adding aluminum powder to a sodium hydroxide solution to etch for a first period of time to obtain a porous aluminum powder; Adding a conductive nanomaterial, a surfactant, and the porous aluminum powder to a solvent, and ultrasonically stirring for a second period of time to obtain a modified porous aluminum powder dispersion; Adding a nickel source, a cobalt source, and a complexing agent to the modified porous aluminum powder dispersion, adjusting the pH to 7-8, and continuously stirring at a first temperature for a third period of time to form a nickel-cobalt-modified porous aluminum powder gel; After drying the nickel-cobalt-modified porous aluminum powder gel at a second temperature for a fourth period of time, calcining at a third temperature and in a nitrogen atmosphere for a fifth period of time to obtain the nickel-coated aluminum powder with a high specific surface area.

[0010] In a third aspect, the present application provides a hydrogen production method, which uses the nickel-coated aluminum powder with a high specific surface area as a reaction catalyst.

[0011] Beneficial technical effects: By etching, modifying, coating, and calcining the aluminum powder, the obtained nickel-coated aluminum powder has a porous structure, greatly improving the specific surface area.

[0012] When aluminum is etched with sodium hydroxide, a chemical reaction occurs to generate hydrogen bubbles. During the process of the bubbles escaping, micron- to nanometer-scale pores are formed on the surface of the aluminum powder. At the same time, water participates in the etching process, and reactive hydroxyl groups are generated on the pore surfaces and the aluminum powder surface. When the conductive nanomaterials are mixed and dispersed with the porous aluminum powder in a solvent, they will adsorb onto the surface and into the pore structure of the porous aluminum powder. After further adding a nickel source and a complexing agent, and heating and stirring, the formed nickel-cobalt-modified porous aluminum powder gel prevents the shedding of the conductive nanomaterials adsorbed on the surface and in the pore structure of the porous aluminum powder. After calcination treatment, the organic groups on the conductive nanomaterials react with the hydroxyl groups on the porous aluminum powder at high temperature and are bonded together by chemical bonds, making the combination more firm. At the same time, the high-valent nickel and high-valent cobalt in the nickel-cobalt-modified porous aluminum powder gel are reduced to metallic nickel and metallic cobalt by the reducing gas generated from the decomposition of the organic components in the gel, forming a cobalt-nickel-containing layer coated on the modified porous aluminum powder. Finally, nickel-coated aluminum powder composed of the cobalt-nickel-containing layer, conductive nanomaterials, and porous aluminum powder is obtained. The prepared nickel-coated aluminum powder has many pores and channels, greatly increasing the specific surface area of the nickel-coated aluminum powder, which can serve as active sites for catalytic reactions. Moreover, the nickel layer also contains cobalt, which can further form bimetallic active sites with nickel, enhancing the catalytic performance of the nickel-coated aluminum powder. In addition, both the cobalt-nickel-containing layer and aluminum itself have good electrical conductivity. After being compounded with the conductive nanomaterials with a conjugated electron structure, the conductive network is more perfect and the electron transport path is more abundant, thus significantly improving the electrical conductivity and electromagnetic shielding performance of the nickel-coated aluminum powder. Description of the Drawings

[0013] Figure 1 It is a schematic diagram of the reaction mechanism for preparing nickel-coated aluminum powder.

[0014] Figure 2 It is a schematic diagram of the process for preparing nickel-coated aluminum powder. Detailed Embodiments

[0015] In order to make the content described in this application easier to understand, the following further describes the technical solutions of this application in combination with specific embodiments, but this application is not limited thereto. Any equivalent transformation or simple substitution made according to the substantial content of this application shall fall within the protection scope of this application.

[0016] In this application, the singular forms of "is", "or", "a", "any one", and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0017] This application adopts the following technical solutions: In a first aspect, the present application provides a nickel-coated aluminum powder with a high specific surface area. The nickel-coated aluminum powder includes modified porous aluminum powder and a cobalt-nickel-containing layer; the cobalt-nickel-containing layer coats the pore structure and the outer surface of the modified porous aluminum powder; the modified porous aluminum powder includes porous aluminum powder and conductive nanomaterials; the conductive nanomaterials are loaded on the pore structure and the outer surface of the porous aluminum powder; the conductive nanomaterials include any one of graphene oxide and carboxylated carbon nanotubes. The schematic diagram of the reaction mechanism for preparing the nickel-coated aluminum powder is as shown in Figure 1 shown.

[0018] In a second aspect, the present application provides a method for preparing a nickel-coated aluminum powder with a high specific surface area, as shown in Figure 2 shown, including: Under nitrogen protection, adding aluminum powder to a sodium hydroxide solution for etching for a first period of time to obtain porous aluminum powder; Adding the conductive nanomaterials, a surfactant, and the porous aluminum powder to a solvent, and ultrasonically stirring for a second period of time to obtain a dispersion of modified porous aluminum powder; Adding a nickel source, a cobalt source, and a complexing agent to the dispersion of modified porous aluminum powder, adjusting the pH to 7-8, and continuously stirring at a first temperature for a third period of time to form a nickel-cobalt-modified porous aluminum powder gel; After drying the nickel-cobalt-modified porous aluminum powder gel at a second temperature for a fourth period of time, calcining at a third temperature and in a nitrogen atmosphere for a fifth period of time to obtain the nickel-coated aluminum powder with a high specific surface area.

[0019] In a possible implementation, the particle size range of the aluminum powder is 1-100 μm; the concentration of the sodium hydroxide solution is 1-3 mol / L.

[0020] In a possible implementation, the mass ratio of the conductive nanomaterials, the surfactant, the porous aluminum powder, the solvent, the nickel source, the cobalt source, and the complexing agent is: (1-3):(1-5):(40-60):(30-50):(5-15):(1-3):(5-10).

[0021] In a possible implementation, the surfactant includes at least one of cetyltrimethylammonium bromide, sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and polyethylene glycol octylphenyl ether.

[0022] In a possible implementation, the solvent includes at least one of deionized water, ethanol, and isopropanol.

[0023] In a possible implementation, the nickel source includes at least one of nickel acetate, nickel chloride, nickel sulfate, and nickel nitrate; the cobalt source includes at least one of cobalt acetate, cobalt chloride, and cobalt nitrate.

[0024] In a possible implementation, platinum and palladium can be combined with nickel in the fcc lattice to further increase the specific surface area. Specifically, the cobalt source is further replaced with a platinum source or a palladium source; the platinum source includes at least one of chloroplatinic acid and platinum nitrate; the palladium source includes at least one of palladium chloride and palladium nitrate.

[0025] The added platinum interacts more strongly with nickel, causing the surface atoms of the fcc lattice nickel layer to rearrange, forming more micropores or defects, thereby increasing the specific surface area; the added palladium inhibits the grain growth of fcc lattice nickel, keeping its grain size small, and thus increasing the specific surface area; both can improve the specific surface area of the finally prepared nickel-coated aluminum powder.

[0026] In this application, fcc lattice nickel is creatively prepared in-situ, and palladium and platinum are synchronously prepared in-situ. The in-situ formation of palladium and platinum plays a role in increasing the specific surface area of fcc lattice nickel in different dimensions, thus facilitating the generation of nickel-coated aluminum powder with a high specific surface area.

[0027] In a possible implementation, the complexing agent includes any one of tartaric acid, oxalic acid, ethylenediaminetetraacetic acid, and acetylacetone.

[0028] In a possible implementation, the first duration is 30 - 50 min, the second duration is 10 - 15 min, the third duration is 1 - 3 h, the fourth duration is 6 - 8 h, and the fifth duration is 3 - 5 h.

[0029] In a possible implementation, the first temperature is 60 - 80 °C, the second temperature is 80 - 100 °C, and the third temperature is 300 - 500 °C.

[0030] In a third aspect, this application provides a hydrogen production method, which uses nickel-coated aluminum powder with a high specific surface area as a reaction catalyst.

[0031] In a possible implementation, the hydrogen production method includes: Mixing nickel-coated aluminum powder with a high specific surface area and a binder in a set mass ratio to obtain a mixture; Extruding and molding the mixture to obtain a reaction catalyst with a specific shape; Loading the reaction catalyst into a fixed-bed reactor, and gasifying an aqueous methanol solution and then introducing it into the fixed-bed reactor; Under a certain temperature and the catalytic action of the reaction catalyst, methanol in the aqueous methanol solution reacts with water to generate hydrogen.

[0032] In a possible implementation, the mass ratio of the nickel-coated aluminum powder with a high specific surface area to the binder is (80 - 90):(10 - 20).

[0033] In a possible implementation, the shape of the reaction catalyst includes any one of granular, spherical, and honeycomb shapes.

[0034] In a possible implementation, the temperature of the reforming reaction of methanol and water is 200 - 400 °C.

[0035] The following will specifically describe a high specific surface area nickel-coated aluminum powder and its preparation method provided by the present application in combination with different embodiments.

[0036] Example 1: As Figure 2 shown, a high specific surface area nickel-coated aluminum powder and its preparation method include the following steps: 1. Under nitrogen protection, add aluminum powder to 1 mol / L sodium hydroxide solution and etch for 30 min to obtain porous aluminum powder; 2. Add 1 g of carboxylated carbon nanotubes, 2 g of cetyltrimethylammonium bromide, and 42 g of porous aluminum powder to 30 g of deionized water, and ultrasonically stir for 30 min to obtain a modified porous aluminum powder dispersion; 3. Add 14 g of nickel acetate, 1 g of cobalt acetate, and 10 g of tartaric acid to the modified porous aluminum powder dispersion, adjust the pH to 7, and continuously stir at 60 °C for 3 h to form a nickel-cobalt - modified porous aluminum powder gel; 4. After drying the nickel-cobalt - modified porous aluminum powder gel at 80 °C for 7 h, calcine it at 300 °C in a nitrogen atmosphere for 5 h to obtain the high specific surface area nickel-coated aluminum powder.

[0037] Load the prepared nickel-coated aluminum powder onto the electrode material and catalyze hydrogen production in an alkaline hydrogen production electrolytic cell.

[0038] Example 2: As Figure 2 shown, a high specific surface area nickel-coated aluminum powder and its preparation method include the following steps: 1. Under nitrogen protection, add aluminum powder to 3 mol / L sodium hydroxide solution and etch for 10 min to obtain porous aluminum powder; 2. Add 2 g of graphene oxide, 3 g of sodium dodecyl sulfate, and 50 g of porous aluminum powder to 30 g of ethanol, and ultrasonically stir for 40 min to obtain a modified porous aluminum powder dispersion; 3. Add 8 g of nickel chloride, 2 g of cobalt nitrate, and 5 g of oxalic acid to the modified porous aluminum powder dispersion, adjust the pH to 7.5, and continuously stir at 70 °C for 2 h to form a nickel-cobalt - modified porous aluminum powder gel; 4. After drying the nickel-cobalt - modified porous aluminum powder gel at 90 °C for 8 h, calcine it at 400 °C in a nitrogen atmosphere for 4 h to obtain the high specific surface area nickel-coated aluminum powder.

[0039] The prepared nickel-coated aluminum powder was loaded onto the same electrode material as in Example 1 and used to catalyze hydrogen production in the same alkaline hydrogen production electrolytic cell as in Example 1.

[0040] Example 3: As Figure 2 shown, a nickel-coated aluminum powder with a high specific surface area and a preparation method thereof include the following steps: 1. Under nitrogen protection, aluminum powder was added to a 2 mol / L sodium hydroxide solution for etching for 20 min to obtain porous aluminum powder; 2. 3 g of graphene oxide, 5 g of sodium dodecylbenzenesulfonate, and 45 g of porous aluminum powder were added to 25 g of isopropanol, and ultrasonically stirred for 50 min to obtain a modified porous aluminum powder dispersion; 3. 11 g of nickel sulfate, 3 g of cobalt chloride, and 8 g of ethylenediaminetetraacetic acid were added to the modified porous aluminum powder dispersion, the pH was adjusted to 8, and the mixture was continuously stirred at 80 °C for 1 h to form a nickel-cobalt-modified porous aluminum powder gel; 4. After drying the nickel-cobalt-modified porous aluminum powder gel at 100 °C for 6 h, it was calcined at 500 °C in a nitrogen atmosphere for 3 h to obtain the nickel-coated aluminum powder with a high specific surface area.

[0041] The prepared nickel-coated aluminum powder was loaded onto the same electrode material as in Example 1 and used to catalyze hydrogen production in the same alkaline hydrogen production electrolytic cell as in Example 1.

[0042] Example 4: As Figure 2 shown, a nickel-coated aluminum powder with a high specific surface area and a preparation method thereof include the following steps: 1. Under nitrogen protection, aluminum powder was added to a 1.5 mol / L sodium hydroxide solution for etching for 20 min to obtain porous aluminum powder; 2. 1 g of carboxylated carbon nanotubes, 1 g of polyethylene glycol octyl phenyl ether, and 46 g of porous aluminum powder were added to 34 g of deionized water, and ultrasonically stirred for 30 min to obtain a modified porous aluminum powder dispersion; 3. 11 g of nickel nitrate, 1 g of cobalt acetate, and 6 g of acetylacetone were added to the modified porous aluminum powder dispersion, the pH was adjusted to 7, and the mixture was continuously stirred at 60 °C for 1.5 h to form a nickel-cobalt-modified porous aluminum powder gel; 4. After drying the nickel-cobalt-modified porous aluminum powder gel at 80 °C for 6.5 h, it was calcined at 300 °C in a nitrogen atmosphere for 3.5 h to obtain the nickel-coated aluminum powder with a high specific surface area.

[0043] The prepared nickel-coated aluminum powder was loaded onto the same electrode material as in Example 1 and used to catalyze hydrogen production in the same alkaline hydrogen production electrolytic cell as in Example 1.

[0044] Example 5: AsFigure 2 As shown, a nickel-coated aluminum powder with high specific surface area and its preparation method include the following steps: 1. Under nitrogen protection, add aluminum powder into 2.5 mol / L sodium hydroxide solution and etch for 15 min to obtain porous aluminum powder; 2. Add 2 g of graphene oxide, 2 g of cetyltrimethylammonium bromide, and 42 g of porous aluminum powder into 36 g of ethanol, and ultrasonically stir for 45 min to obtain a modified porous aluminum powder dispersion; 3. Add 10 g of nickel acetate, 1 g of cobalt chloride, and 7 g of tartaric acid into the modified porous aluminum powder dispersion, adjust the pH to 8, and continuously stir at 75 °C for 2.5 h to form a nickel-cobalt - modified porous aluminum powder gel; 4. After drying the nickel-cobalt - modified porous aluminum powder gel at 90 °C for 7 h, calcine it at 400 °C in a nitrogen atmosphere for 4.5 h to obtain the nickel-coated aluminum powder with high specific surface area.

[0045] Load the prepared nickel-coated aluminum powder onto the same electrode material as in Example 1, and catalyze hydrogen production in the same alkaline hydrogen production electrolytic cell as in Example 1.

[0046] Example 6: As Figure 2 shown, a nickel-coated aluminum powder with high specific surface area and its preparation method include the following steps: 1. Under nitrogen protection, add aluminum powder into 3 mol / L sodium hydroxide solution and etch for 15 min to obtain porous aluminum powder; 2. Add 3 g of carboxylated carbon nanotubes, 4 g of sodium dodecyl sulfate, and 42 g of porous aluminum powder into 35 g of isopropanol, and ultrasonically stir for 50 min to obtain a modified porous aluminum powder dispersion; 3. Add 10 g of nickel chloride, 2 g of cobalt nitrate, and 4 g of oxalic acid into the modified porous aluminum powder dispersion, adjust the pH to 7, and continuously stir at 70 °C for 2 h to form a nickel-cobalt - modified porous aluminum powder gel; 4. After drying the nickel-cobalt - modified porous aluminum powder gel at 100 °C for 6 h, calcine it at 500 °C in a nitrogen atmosphere for 3.5 h to obtain the nickel-coated aluminum powder with high specific surface area.

[0047] Load the prepared nickel-coated aluminum powder onto the same electrode material as in Example 1, and catalyze hydrogen production in the same alkaline hydrogen production electrolytic cell as in Example 1.

[0048] Comparative Example 1: A nickel-coated aluminum powder with high specific surface area and its preparation method include the following steps: 1. Under nitrogen protection, add aluminum powder into 1 mol / L sodium hydroxide solution and etch for 30 min to obtain porous aluminum powder; 2. Add 2 g of cetyltrimethylammonium bromide and 43 g of porous aluminum powder to 30 g of deionized water, and ultrasonically stir for 30 min to obtain a modified porous aluminum powder dispersion; 3. Add 14 g of nickel acetate, 1 g of cobalt acetate and 10 g of tartaric acid to the modified porous aluminum powder dispersion, adjust the pH to 7, and continuously stir at 60 °C for 3 h to form a nickel-cobalt-modified porous aluminum powder gel; 4. After drying the nickel-cobalt-modified porous aluminum powder gel at 80 °C for 7 h, calcine it at 300 °C in a nitrogen atmosphere for 5 h to obtain the high specific surface area nickel-coated aluminum powder.

[0049] Load the prepared nickel-coated aluminum powder onto the same electrode material as in Example 1, and catalyze hydrogen production in the same alkaline hydrogen production electrolytic cell as in Example 1.

[0050] Comparative Example 2: A nickel-coated aluminum powder and its preparation method, comprising the following steps: 1. Add 3 g of graphene oxide, 5 g of sodium dodecylbenzenesulfonate and 45 g of aluminum powder to 25 g of isopropanol, and ultrasonically stir for 50 min to obtain an aluminum powder dispersion; 2. Add 11 g of nickel sulfate, 3 g of cobalt chloride and 8 g of ethylenediaminetetraacetic acid to the aluminum powder dispersion, adjust the pH to 8, and continuously stir at 80 °C for 1 h to form a nickel-cobalt-aluminum powder gel; 3. After drying the nickel-cobalt-aluminum powder gel at 100 °C for 6 h, calcine it at 500 °C in a nitrogen atmosphere for 3 h to obtain the nickel-coated aluminum powder.

[0051] Load the prepared nickel-coated aluminum powder onto the same electrode material as in Example 1, and catalyze hydrogen production in the same alkaline hydrogen production electrolytic cell as in Example 1.

[0052] Comparative Example 3: A nickel-coated aluminum powder and its preparation method, comprising the following steps: 1. Add 4 g of sodium dodecyl sulfate and 45 g of aluminum powder to 35 g of isopropanol, and ultrasonically stir for 50 min to obtain an aluminum powder dispersion; 2. Add 10 g of nickel chloride, 2 g of cobalt nitrate and 4 g of oxalic acid to the aluminum powder dispersion, adjust the pH to 7, and continuously stir at 70 °C for 2 h to form a nickel-cobalt-aluminum powder gel; 3. After drying the nickel-cobalt-aluminum powder gel at 100 °C for 6 h, calcine it at 500 °C in a nitrogen atmosphere for 3.5 h to obtain the nickel-coated aluminum powder.

[0053] Load the prepared nickel-coated aluminum powder onto the same electrode material as in Example 1, and catalyze hydrogen production in the same alkaline hydrogen production electrolytic cell as in Example 1.

[0054] The BET specific surface area measurement method was used to test the specific surface area values of the nickel-coated aluminum powders prepared in the examples and comparative examples.

[0055] A resistance tester was used to test the resistance values of the nickel-coated aluminum powders prepared in the examples and comparative examples to reflect their electrical conductivity.

[0056] An electromagnetic shielding effectiveness test device was used to test the electromagnetic shielding values of the nickel-coated aluminum powders prepared in the examples and comparative examples.

[0057] The volume of hydrogen gas produced by the same mass of nickel-coated aluminum powder in an alkaline hydrogen production electrolytic cell under the same reaction conditions within the same time was collected and measured to reflect the strength of its hydrogen production catalytic ability.

[0058] The test results of the above tests are statistically shown in Table 1.

[0059] Table 1 Test results of nickel-coated aluminum powders prepared in examples and comparative examples

[0060] As can be seen from Table 1, the specific surface areas, electromagnetic shielding values, and hydrogen production efficiencies of Examples 1-6 are significantly higher than those of Comparative Examples 1-3; at the same time, the resistance values of Examples 1-6 are significantly lower than those of Comparative Examples 1-3.

[0061] This is because the nickel-coated aluminum powders prepared in Examples 1-6 have many pores and channels, greatly increasing the specific surface area of the nickel-coated aluminum powder, which can serve as active sites for catalytic reactions; moreover, the nickel layer also contains cobalt, which can further form bimetallic active sites with nickel, enhancing the catalytic performance of the nickel-coated aluminum powder. And both the cobalt-containing nickel layer and aluminum itself have good electrical conductivity. After being compounded with conductive nanomaterials with a conjugated electron structure, the conductive network is more perfect and the electron transport path is more abundant, thus significantly improving the electrical conductivity and electromagnetic shielding performance of the nickel-coated aluminum powder.

[0062] In contrast, in Comparative Example 3, no conductive nanomaterials were added and the aluminum powder was not etched, so a porous structure could not be formed, ultimately resulting in the smallest specific surface area of the prepared nickel-coated aluminum powder, and the worst electrical conductivity and electromagnetic shielding performance.

[0063] In Comparative Example 2, conductive nanomaterials were added, but the aluminum powder was not etched to form a porous structure. Therefore, the adsorption amount of the conductive nanomaterials on the surface of the aluminum powder was relatively small. After the nickel layer, aluminum, and conductive nanomaterials were compounded, the formed conductive network was not perfect. Ultimately, the nickel-coated aluminum powder had certain electrical conductivity and electromagnetic shielding performance, but it was still weak.

[0064] In Comparative Example 1, the aluminum powder was etched to form a porous structure, and the prepared nickel-coated aluminum powder had a relatively high specific surface area. However, due to the absence of conductive nanomaterials, the electrical conductivity and electromagnetic shielding performance were weak.

[0065] The above results show and describe the basic principles, main features and advantages of the present application.

[0066] Those skilled in the art should understand that the present application is not limited by the above embodiments. The above embodiments and the descriptions in the specification only illustrate the principles of the present application. Without departing from the spirit and scope of the present application, the present application will have various changes and improvements, and these changes and improvements all fall within the scope of the present application claimed. The scope of protection claimed by the present application is defined by the equivalents of the appended claims.

Claims

1. A nickel-coated aluminum powder with a high specific surface area, characterized in that, The nickel-coated aluminum powder includes modified porous aluminum powder and a cobalt-containing nickel layer; the cobalt-containing nickel layer coats the pore structure and the outer surface of the modified porous aluminum powder; the modified porous aluminum powder includes porous aluminum powder and a conductive nanomaterial; the conductive nanomaterial is loaded on the pore structure and the outer surface of the porous aluminum powder; the conductive nanomaterial includes any one of graphene oxide and carboxylated carbon nanotubes.

2. The preparation method of a nickel-coated aluminum powder with a high specific surface area according to claim 1, characterized in that, Comprising: Under nitrogen protection, adding aluminum powder into a sodium hydroxide solution to etch for a first duration to obtain porous aluminum powder; Adding the conductive nanomaterial, a surfactant, and the porous aluminum powder into a solvent, and ultrasonically stirring for a second duration to obtain a modified porous aluminum powder dispersion; Adding a nickel source, a cobalt source, and a complexing agent into the modified porous aluminum powder dispersion, adjusting the pH to 7-8, and continuously stirring at a first temperature for a third duration to form a nickel-cobalt - modified porous aluminum powder gel; After drying the nickel-cobalt - modified porous aluminum powder gel at a second temperature for a fourth duration, calcining at a third temperature and in a nitrogen atmosphere for a fifth duration to obtain the high specific surface area nickel-coated aluminum powder.

3. The preparation method of a nickel-coated aluminum powder with a high specific surface area according to claim 2, characterized in that, The particle size range of the aluminum powder is 1-100 μm; the concentration of the sodium hydroxide solution is 1-3 mol / L.

4. The preparation method of a nickel-coated aluminum powder with a high specific surface area according to claim 2, characterized in that, The mass ratio of the conductive nanomaterial, the surfactant, the porous aluminum powder, the solvent, the nickel source, the cobalt source, and the complexing agent is: (1-3):(1-5):(40-60):(30-50):(5-15):(1-3):(5-10).

5. The preparation method of a nickel-coated aluminum powder with a high specific surface area according to claim 2, characterized in that, The surfactant includes at least one of cetyltrimethylammonium bromide, sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and polyethylene glycol octylphenyl ether.

6. The preparation method of a nickel-coated aluminum powder with a high specific surface area according to claim 2, characterized in that, The solvent includes at least one of deionized water, ethanol, and isopropanol.

7. The preparation method of a nickel-coated aluminum powder with a high specific surface area according to claim 2, characterized in that, The nickel source includes at least one of nickel acetate, nickel chloride, nickel sulfate, and nickel nitrate; the cobalt source includes at least one of cobalt acetate, cobalt chloride, and cobalt nitrate.

8. The preparation method of a nickel-coated aluminum powder with a high specific surface area according to claim 2, characterized in that, The complexing agent includes any one of tartaric acid, oxalic acid, ethylenediaminetetraacetic acid, and acetylacetone.

9. The preparation method of a nickel-coated aluminum powder with a high specific surface area according to claim 2, characterized in that, The first duration is 10-30 min, the second duration is 30-60 min, the third duration is 1-3 h, the fourth duration is 6-8 h, and the fifth duration is 3-5 h; the first temperature is 60-80 °C, the second temperature is 80-100 °C, and the third temperature is 300-500 °C.

10. A hydrogen production method, characterized in that, The hydrogen production method uses the high specific surface area nickel-coated aluminum powder described in claim 1 as a reaction catalyst.

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