Aluminum composite material for hydrogen production by hydrolysis, preparation method therefor, and use thereof

Abstract

An aluminum composite material for hydrogen production by hydrolysis, comprising an aluminum-based core and a composite layer formed on the surface of the aluminum-based core. The aluminum-based core comprises, by mass fraction: 90-95% of aluminum and the balance being a magnesium-sodium alloy. The composite layer comprises a carbon-based skeleton attached to the surface of the aluminum-based core and a titanium-iron oxide formed on the carbon-based skeleton. According to the composite material, the aluminum-based core can be prevented from reacting with oxygen to generate an aluminum oxide thin film, thereby increasing the hydrogen yield and hydrogen production rate of the aluminum composite material during hydrogen production. The present invention also relates to a preparation method for and a use of the aluminum composite material for hydrogen production by hydrolysis.

Description

An aluminum composite material for hydrogen production by hydrolysis, its preparation method and application Technical Field

[0001] This invention relates to the field of hydrogen energy production technology, and in particular to an aluminum composite material for hydrogen production by hydrolysis, its preparation method and application. Background Technology

[0002] In the current energy system, fossil fuels still dominate, but the environmental pollution and resource depletion they bring cannot be ignored. Hydrogen energy, with its unique cleanliness and high energy density, is regarded as one of the most promising renewable energy sources in the 21st century. Hydrogen produces only water after combustion and emits no greenhouse gases, which makes hydrogen energy play an important role in achieving global emission reduction targets. With the intensification of the global energy crisis and environmental problems, countries have incorporated hydrogen energy into their future energy strategies in order to achieve energy structure transformation and sustainable economic development.

[0003] There are various methods for producing hydrogen, mainly including fossil fuel reforming, water electrolysis, photocatalytic water splitting, and biomass conversion. Among these, fossil fuel reforming is currently the most important method, accounting for approximately 95% of global hydrogen production. However, this method still relies on non-renewable fossil resources and is accompanied by carbon dioxide emissions, making it difficult to meet the requirements of sustainable development. In contrast, hydrogen production through the reaction of metals with water has become a research hotspot due to its simple process, low energy consumption, and high hydrogen production rate. Aluminum, as a metallic element that reacts with water to produce hydrogen and harmless alumina byproducts, has attracted considerable attention.

[0004] However, the activity of aluminum is mainly limited by the aluminum oxide film formed on its surface. Although this film is only a few nanometers thick, it is extremely dense and has strong chemical stability, which greatly hinders the contact reaction between active aluminum and water. Therefore, how to effectively remove or thin this oxide film has become a key issue in improving the reaction rate between aluminum and water and realizing aluminum-based hydrogen production. Summary of the Invention

[0005] The purpose of this invention is to provide an aluminum composite material for hydrogen production by hydrolysis, its preparation method and application.

[0006] In a first aspect, the present invention provides an aluminum composite material for hydrogen production by hydrolysis, comprising an aluminum-based core and a composite layer formed on the surface of the aluminum-based core, wherein the aluminum-based core comprises 90-95% aluminum and the balance being a magnesium-sodium alloy by mass fraction; the composite layer comprises a carbon-based skeleton attached to the surface of the aluminum-based core and titanium-iron oxide formed on the carbon-based skeleton.

[0007] The aluminum composite material provided by this invention can effectively improve the activity of aluminum in the hydrogen production process by compounding magnesium and sodium elements into the aluminum-based core. In addition, by forming a composite layer on the surface of the aluminum-based core, the aluminum-based core can be protected to prevent the aluminum-based core from reacting with oxygen to form an aluminum oxide film. At the same time, the carbon-based skeleton in the composite layer can fully encapsulate the aluminum-based core, and the carbon-based skeleton and titanium iron oxide can provide additional catalytic active sites, which can effectively improve the reaction efficiency of aluminum in the hydrogen production process. Meanwhile, titanium iron oxide can effectively improve the support and stability of the carbon-based skeleton.

[0008] Optionally, the aluminum-based core comprises 90-95% aluminum, 2-5% magnesium, and the balance sodium by mass fraction.

[0009] Optionally, the purity of aluminum in the aluminum-based core is greater than or equal to 99.9%.

[0010] Optionally, the carbon-based framework material includes at least one of graphene and carbon nanotubes.

[0011] Optionally, the titanium-iron oxide includes iron oxide and titanium oxide, and the molar ratio of titanium to iron in the titanium-iron oxide is 1:(0.8-1.2).

[0012] Optionally, the loading of the composite layer on the aluminum composite material is 10-20%.

[0013] Secondly, the present invention provides a method for preparing an aluminum composite material, comprising the following steps: obtaining an aluminum-based core by high-energy ball milling of elemental aluminum and a magnesium-sodium alloy at 300-500°C; dispersing the aluminum-based core in tetramethylsilane by ultrasonication, and then separating and drying it to obtain an activated matrix; dispersing the activated matrix and carbon-based raw materials by ultrasonication in a non-polar solvent to obtain a composite intermediate; and calcining the composite intermediate in an oxygen atmosphere at 200-300°C and then cooling it to obtain the aluminum composite material.

[0014] Optionally, the nonpolar solvent includes at least one of n-hexane, benzene, carbon tetrachloride, and diethyl ether.

[0015] Optionally, the organic titanium solution includes at least one of tetraisopropyl titanate and tetrabutyl titanate.

[0016] Optionally, the organoiron includes iron pentacarbonyl.

[0017] Thirdly, the present invention also provides an application of aluminum composite material for hydrogen production by hydrolysis. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, 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. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art to which this invention pertains.

[0019] This invention provides an aluminum composite material for hydrogen production via hydrolysis, comprising an aluminum-based core and a composite layer formed on the surface of the aluminum-based core. During the hydrogen production reaction via hydrolysis, the aluminum-based core reacts with water to produce hydrogen, while the composite layer can catalyze the hydrogen production reaction and protect the aluminum composite material during transportation and storage, preventing the aluminum-based core from reacting with air and thus inhibiting its reactivity.

[0020] In fact, the aluminum-based core comprises 90-95% aluminum by mass and the balance being a magnesium-sodium alloy. Magnesium and sodium both have similar activity to aluminum and can form a micro-current reaction with aluminum, thereby inhibiting the oxidation reaction of the aluminum-based core during storage. At the same time, it can also improve the reactivity of aluminum and the mechanical strength of the aluminum-based core.

[0021] In some embodiments, the aluminum-based core comprises 90-95% aluminum, 2-5% magnesium, and the balance sodium by mass fraction. In practice, by controlling the amounts of magnesium and sodium within the aluminum-based core, the reaction rate during the hydrolysis hydrogen production reaction and the mechanical strength of the aluminum-based core can be effectively balanced. Specifically, the purity of aluminum in the aluminum-based core is greater than or equal to 99.9%, thereby effectively reducing impurity elements within the aluminum-based core and increasing the hydrogen production per unit of aluminum composite material.

[0022] In some embodiments, the carbon-based framework material includes at least one of graphene and carbon nanotubes. By forming a carbon-based framework on the outer surface of the aluminum-based core, the aluminum-based core can be protected, while water can penetrate into the carbon-based framework and come into contact with the aluminum-based core during hydrogen production.

[0023] In addition, the carbon-based framework provides excellent chemical stability, effectively transferring heat at the reaction core during the hydrolysis reaction of the aluminum-based core, and facilitating the escape of hydrogen from the carbon-based framework, thereby avoiding negative impacts on the hydrolysis reaction of the aluminum-based core.

[0024] In fact, titanium iron oxide includes iron oxide and titanium oxide, and the molar ratio of titanium to iron in titanium iron oxide is 1:(0.8-1.2), and the loading of the composite layer on the aluminum composite material is 10-20%.

[0025] This invention also provides a method for preparing an aluminum composite material, comprising the following steps:

[0026] S1. An aluminum-based core is prepared by high-energy ball milling of elemental aluminum and magnesium-sodium alloy at 300-500℃.

[0027] S2. After ultrasonically dispersing the aluminum-based core in tetramethylsilane, the activated matrix is ​​separated and dried.

[0028] S3. The activated matrix and carbon-based raw materials are ultrasonically dispersed in a non-polar solvent to obtain a composite intermediate.

[0029] S4. After the composite intermediate is alternately impregnated in organic titanium and organic iron, it is calcined in an oxygen atmosphere at 200-300℃ and then cooled to obtain an aluminum composite material.

[0030] In some embodiments, during step S1, aluminum, magnesium, and sodium with a purity greater than or equal to 99.9% are subjected to high-energy ball milling in a vacuum environment at 300-500°C. The ball-to-material ratio can be (10-20):1, and the milling time can be 2-10 hours. In fact, high-energy ball milling of aluminum, magnesium, and sodium effectively promotes the uniform dispersion of the three metal elements. Simultaneously, the intense collisions and friction during the milling process contribute to a more uniform microstructure of the three metal elements, improving the consistency and structural stability of the aluminum-based core.

[0031] In some embodiments, when performing step S2, after the aluminum-based core is ultrasonically dispersed in pure tetramethylsilane at a frequency of 10 kHz for 10 min, the cavitation effect of the ultrasound can promote the uniform modification of the tetramethylsilane on the surface of the aluminum-based core, thereby improving the adhesion of the aluminum-based core to the carbon-based raw materials, and can also form a coating structure on the surface of the aluminum-based core, thereby improving the uniformity of the adhesion of the carbon-based raw materials.

[0032] In some embodiments, during step S3, the mass ratio of the activated matrix to the carbon-based raw material in the nonpolar solvent is 1:(0.2-0.3). In fact, by controlling the mixing amount of the activated matrix and the carbon-based raw material, the forming thickness of the carbon-based skeleton on the surface of the activated matrix can be effectively controlled, thereby avoiding the impact of excessively large or small thicknesses on the hydrolysis hydrogen production reaction of the aluminum-based core.

[0033] In some embodiments, the nonpolar solvent in step S3 includes at least one of n-hexane, benzene, carbon tetrachloride, and diethyl ether; the organotitanium solution in step S4 includes at least one of tetraisopropyl titanate and tetrabutyl titanate, and the organoiron includes iron pentacarbonyl. Example 1

[0034] This embodiment 1 provides a method for preparing aluminum composite materials for hydrogen production by hydrolysis, including the following steps:

[0035] S1. Metallic aluminum powder, metallic magnesium powder and metallic sodium powder with an average particle size of 100μm and a purity of 99.9% are mixed in a vacuum ball mill jar at a mass ratio of 95:2:3. After vacuuming, the mixture is ball-milled at 400℃ with a ball-to-material ratio of 20:1 for 10 hours. After cooling to room temperature, an aluminum-based core is obtained.

[0036] S2. The aluminum-based core was added to tetramethylsilane at a solid-liquid ratio of 0.05 g / mL under a nitrogen atmosphere. After ultrasonic dispersion at a frequency of 10 kHz for 10 min, it was placed at 45 ℃ for 1 h and then separated. After drying in a vacuum drying oven to constant weight, the activated matrix was obtained.

[0037] S3. The activated matrix and carbon nanotubes were mixed and dispersed in n-hexane at a mass ratio of 1:0.3. After ultrasonic dispersion for 10 min, the mixture was filtered and separated. The mixture was then dried in a vacuum drying oven at 100℃ to constant weight to obtain the composite intermediate.

[0038] S4. The composite intermediate was alternately soaked five times in tetraisopropyl titanate and iron pentacarbonyl, respectively, and then calcined in an oxygen atmosphere at 200-300℃ and cooled to obtain an aluminum composite material.

[0039] Comparative Example 1

[0040] Comparative Example 1 provides a method for preparing an aluminum composite material for hydrogen production by hydrolysis, comprising the following steps:

[0041] D1. After vacuuming, aluminum powder with an average particle size of 100μm and a purity of 99.9% was ball-milled at 400℃ with a ball-to-particle ratio of 20:1 for 10 hours and then cooled to room temperature to obtain an aluminum-based core.

[0042] D2. The aluminum-based core was added to tetramethylsilane at a solid-liquid ratio of 0.05 g / mL under a nitrogen atmosphere. After ultrasonic dispersion at a frequency of 10 kHz for 10 min, it was placed at 45 ℃ for 1 h and then separated. After drying in a vacuum drying oven to constant weight, the activated matrix was obtained.

[0043] S3. The activated matrix and carbon nanotubes were mixed and dispersed in n-hexane at a mass ratio of 1:0.3. After ultrasonic dispersion for 10 min, the mixture was filtered and separated. The mixture was then dried in a vacuum drying oven at 100℃ to constant weight to obtain the composite intermediate.

[0044] S4. The composite intermediate was alternately soaked five times in tetraisopropyl titanate and iron pentacarbonyl, respectively, and then calcined in an oxygen atmosphere at 200-300℃ and cooled to obtain an aluminum composite material.

[0045] Comparative Example 2

[0046] Comparative Example 2 provides a method for preparing an aluminum composite material for hydrogen production by hydrolysis, comprising the following steps:

[0047] D1. Metallic aluminum powder and metallic magnesium powder with an average particle size of 100μm and a purity of 99.9% are mixed in a vacuum ball mill jar at a mass ratio of 98:2. After vacuuming, the mixture is ball-milled at 400℃ with a ball-to-material ratio of 20:1 for 10 hours. After cooling to room temperature, an aluminum-based core is obtained.

[0048] S2. The aluminum-based core was added to tetramethylsilane at a solid-liquid ratio of 0.05 g / mL under a nitrogen atmosphere. After ultrasonic dispersion at a frequency of 10 kHz for 10 min, it was placed at 45 ℃ for 1 h and then separated. After drying in a vacuum drying oven to constant weight, the activated matrix was obtained.

[0049] S3. The activated matrix and carbon nanotubes were mixed and dispersed in n-hexane at a mass ratio of 1:0.3. After ultrasonic dispersion for 10 min, the mixture was filtered and separated. The mixture was then dried in a vacuum drying oven at 100℃ to constant weight to obtain the composite intermediate.

[0050] S4. The composite intermediate was alternately soaked five times in tetraisopropyl titanate and iron pentacarbonyl, respectively, and then calcined in an oxygen atmosphere at 200-300℃ and cooled to obtain an aluminum composite material.

[0051] Comparative Example 3

[0052] Comparative Example 3 provides a method for preparing an aluminum composite material for hydrogen production by hydrolysis, comprising the following steps:

[0053] D1. Metallic aluminum powder and metallic sodium powder with an average particle size of 100μm and a purity of 99.9% are mixed in a vacuum ball mill jar at a mass ratio of 97:3. After vacuuming, the mixture is ball milled at 400℃ with a ball-to-material ratio of 20:1 for 10 hours. After cooling to room temperature, an aluminum-based core is obtained.

[0054] S2. The aluminum-based core was added to tetramethylsilane at a solid-liquid ratio of 0.05 g / mL under a nitrogen atmosphere. After ultrasonic dispersion at a frequency of 10 kHz for 10 min, it was placed at 45 ℃ for 1 h and then separated. After drying in a vacuum drying oven to constant weight, the activated matrix was obtained.

[0055] S3. The activated matrix and carbon nanotubes were mixed and dispersed in n-hexane at a mass ratio of 1:0.3. After ultrasonic dispersion for 10 min, the mixture was filtered and separated. The mixture was then dried in a vacuum drying oven at 100℃ to constant weight to obtain the composite intermediate.

[0056] S4. The composite intermediate was alternately soaked five times in tetraisopropyl titanate and iron pentacarbonyl, respectively, and then calcined in an oxygen atmosphere at 200-300℃ and cooled to obtain an aluminum composite material.

[0057] Comparative Example 4

[0058] Comparative Example 4 provides a method for preparing an aluminum composite material for hydrogen production by hydrolysis, comprising the following steps:

[0059] D1. Metallic aluminum powder, metallic magnesium powder, and metallic sodium powder, all with an average particle size of 100μm and a purity of 99.9%, are mixed in a vacuum ball mill jar at a mass ratio of 95:2:3. After vacuuming, the mixture is ball-milled at 400℃ with a ball-to-material ratio of 20:1 for 10 hours. After cooling to room temperature, an aluminum-based core is obtained.

[0060] Performance testing

[0061] The aluminum composite materials prepared in Example 1 and Comparative Examples 1 to 4 were mixed with water at 25°C and subjected to hydrolysis. The ratio of actual hydrogen production to theoretical hydrogen production and the hydrogen production rate in the first 5 minutes were tested. The results are shown in Table 1 below.

[0062] Table 1 Hydrogen production performance of aluminum composite materials

[0063]

[0064] While embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations fall within the scope and spirit of the invention as set forth in the claims. Furthermore, the invention described herein may have other embodiments and can be implemented or carried out in various ways.

Claims

1. An aluminum composite material for hydrogen production via hydrolysis, characterized in that, The invention comprises an aluminum-based core and a composite layer formed on the surface of the aluminum-based core. The aluminum-based core comprises 90-95% aluminum and the balance being a magnesium-sodium alloy by mass fraction. The composite layer comprises a carbon-based skeleton attached to the surface of the aluminum-based core and titanium-iron oxide formed on the carbon-based skeleton.

2. The aluminum composite material according to claim 1, characterized in that, The aluminum-based core comprises 90-95% aluminum, 2-5% magnesium, and the balance sodium by mass fraction.

3. The aluminum composite material according to claim 1, characterized in that, The aluminum in the aluminum-based core has a purity greater than or equal to 99.9%.

4. The aluminum composite material according to claim 1, characterized in that, The carbon-based framework material includes at least one of graphene and carbon nanotubes.

5. The aluminum composite material according to claim 1, characterized in that, The titanium-iron oxide includes iron oxide and titanium oxide, and the molar ratio of titanium to iron in the titanium-iron oxide is 1:(0.8-1.2).

6. The aluminum composite material according to claim 1, characterized in that, The composite layer has a loading of 10-20% on the aluminum composite material.

7. A method for preparing an aluminum composite material as described in any one of claims 1 to 6, characterized in that, The process includes the following steps: Aluminum-based cores are prepared by high-energy ball milling of elemental aluminum and magnesium-sodium alloy at 300-500℃; the aluminum-based cores are ultrasonically dispersed in tetramethylsilane, then separated and dried to obtain an activated matrix; the activated matrix and carbon-based raw materials are ultrasonically dispersed in a non-polar solvent to obtain a composite intermediate; the composite intermediate is alternately impregnated in organotitanium and organoiron, then calcined in an oxygen atmosphere at 200-300℃ and cooled to obtain an aluminum composite material.

8. The preparation method according to claim 7, characterized in that, The nonpolar solvent includes at least one of n-hexane, benzene, carbon tetrachloride, and diethyl ether.

9. The preparation method according to claim 7, characterized in that, The organic titanium solution includes at least one of tetraisopropyl titanate and tetrabutyl titanate; and / or, the organic iron includes iron pentacarbonyl.

10. An application of an aluminum composite material as described in any one of claims 1 to 6.

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