Preparation method of hydrogen storage nano titanium-based composite powder

Abstract

The application discloses a preparation method of hydrogen storage nano titanium-based composite powder, which comprises the following steps: adding iron trichloride hexahydrate and tetrabutyl titanate into distilled water according to a mass ratio of 1:5-7, stirring to fully dissolve and disperse, adding anhydrous ethanol after uniform mixing, stirring uniformly, and adjusting the pH of the solution to 8-9; subjecting the obtained mixture to hydrothermal reaction at 120-150 DEG C for 16-20 h to obtain a composite powder product; washing the composite powder product with distilled water, filtering the powder product, drying the filtered and washed product at 50-60 DEG C for 20-24 h; putting the dried product into a tube furnace, sintering the product at 750-800 DEG C under H2 atmosphere for 2-3 h, reducing the obtained product, and grinding the product to obtain nano titanium-iron composite powder. The obtained composite powder is irregular in shape, small in particle size, and large in specific surface area, the hydrogen storage capacity is improved, and the convenience and safety of hydrogen storage and transportation are improved.

Description

Technical Field

[0001] This invention belongs to the field of solid hydrogen storage technology and relates to a method for preparing hydrogen storage nano-titanium-based composite powder. Background Technology

[0002] As the global greenhouse gas emissions problem intensifies, countries around the world are transitioning to cleaner, low-carbon energy sources. Hydrogen energy, as one of the most important forms of clean energy, is therefore receiving increasing attention.

[0003] Hydrogen energy is an abundant, green, low-carbon, and widely applicable secondary energy source, representing a mainstream development direction for the 21st-century new energy system. Hydrogen boasts a high calorific value, three times that of gasoline, 3.9 times that of alcohol, and 4.5 times that of coke. As a widely applicable energy form, hydrogen can be used directly as fuel to power transportation and industry. Furthermore, because it can be stored as a liquid or as an energy storage device, it can be integrated with various energy sources (renewable energy, fossil fuels, and nuclear energy), enabling flexible energy storage based on supply and demand, thus addressing the spatial and temporal balance of energy supply and demand. Moreover, as a crucial raw material for industrial production and decarbonization, hydrogen can be used in product manufacturing or combined with CO2 captured from industrial processes to convert into chemical products. In essence, hydrogen energy can be considered a renewable "petroleum" resource.

[0004] However, hydrogen storage and transportation remain a bottleneck in the hydrogen energy industry chain, encompassing production, storage, transportation, and utilization. Currently, there are three methods for hydrogen storage: high-pressure gaseous storage, liquid storage, and solid-state storage. In practical applications of hydrogen storage, safety and high-density storage are the primary concerns, followed by economic efficiency and convenience. Solid-state hydrogen storage inherently possesses characteristics that most closely address the primary issues of hydrogen storage, offering a crucial solution for high-density and safe hydrogen storage and transportation for two reasons: firstly, it boasts the highest volumetric hydrogen storage density, and secondly, it offers excellent storage safety.

[0005] Titanium is an important strategic resource, widely used in many fields of national defense, aerospace, aviation, and the national economy. Long-term experimental and industrial production practices have proven that titanium and titanium alloys are recognized as ideal metallic structural materials that can replace steel, stainless steel, copper, and their alloys, and solve equipment corrosion problems. Due to the highly reactive chemical properties of titanium, hydrogen can be stored in the form of atoms, molecules, or hydrides in interstitial spaces, defects, or intermetallic compounds. Under certain conditions, it can repeatedly absorb and release hydrogen, with a hydrogen storage capacity of 1000 to 1300 times the volume of the material itself, showing great potential as the main hydrogen-absorbing component in hydrogen storage alloys.

[0006] Titanium-based hydrogen storage alloys in solid hydrogen storage typically include Ti-Fe, Ti-Mn, Ti-Cr, and Ti-Zr, with AB-type TiFe alloys being the most representative. TiFe hydrogen storage alloys are low-cost, easy to produce, and exhibit rapid hydrogen absorption and desorption at room temperature. Furthermore, they have a long cycle life, exceeding 2000 cycles, four times that of rare-earth hydrogen storage alloys, while their raw material cost is only one-third that of rare-earth alloys. However, they readily form a dense TiO2 layer, making activation difficult. Once activated, they readily come into contact with impurity gases such as O2, CO2, and H2O in the air, losing their hydrogen absorption and desorption activity. Currently, these problems are mainly addressed through elemental alloying and surface treatment. Transition elements such as Ni, Mn, and Cr are typically used to replace some of the Fe in TiFe, thereby improving the alloy's activation performance.

[0007] Different preparation methods for titanium-based hydrogen storage alloys lead to significant differences in their structure, thermal stability, and hydrogen absorption / desorption. Preparation methods for Ti-Fe composites include vacuum melting to first form a bulk material, followed by high-energy ball milling (to obtain nanoparticles), belt spinning (to obtain thin films), or atomization (to obtain ultrafine powders). Among these, Haiqin Qu et al. prepared TiFe using radio frequency magnetic levitation melting. 0.86 Mn 0.1-x Co x Alloy. The material is smelted in a water-cooled copper furnace under argon protection. Vacuum smelting and mechanical crushing methods involve large investments and high costs. More importantly, the resulting powder is relatively coarse (it is difficult to achieve the nanoscale, or high-energy ball milling is required to achieve the nanoscale), which leads to a reduction in specific surface area and poor hydrogen adsorption performance. Summary of the Invention

[0008] To address the aforementioned problems, this invention provides a method for preparing hydrogen storage nano-titanium-based composite powder. The resulting composite powder has an irregular shape, small particle size, and large specific surface area, thereby increasing the hydrogen storage capacity and improving the convenience and safety of hydrogen storage and transportation, thus solving the problems existing in the prior art.

[0009] The technical solution adopted in this invention is a method for preparing hydrogen storage nano-titanium-based composite powder, comprising the following steps:

[0010] S1. Add ferric chloride hexahydrate and tetrabutyl titanate to distilled water at a mass ratio of 1:5~7, stir to dissolve and disperse them fully, add anhydrous ethanol after mixing evenly, stir evenly, and then adjust the pH of the solution to 8~9.

[0011] S2, the resulting mixture is hydrothermally reacted at 120~150℃ for 16~20h to obtain the composite powder product;

[0012] S3, wash with distilled water, filter the powder product, filter and wash multiple times, and then dry at 50~60℃ for 20~24h.

[0013] S4. The dried product is placed in a tube furnace and sintered at 750-800℃ for 2-3 h at a heating rate of 8-10℃ / min under H2 atmosphere. The resulting product is reduced and then ground to obtain nano-titanium-iron composite powder, which contains vacancies and lattice distortion, which is beneficial for hydrogen adsorption and storage.

[0014] The beneficial effects of this invention are:

[0015] This invention uses ferric chloride hexahydrate and tetrabutyl titanate as raw materials. Through a hydrothermal reaction with specific process parameters, followed by reduction and grinding, an irregularly shaped composite powder is obtained. This powder has a small particle size, a large specific surface area, and a sufficient number of internal lattice defects. Hydrogen can be stored in interatomic spaces or material defects through diffusion, forming physically adsorbed hydrogen gas. In addition to titanium, the composite powder also contains the crucial element iron. On the one hand, it improves the activation properties of titanium, making it easier to adsorb hydrogen; on the other hand, iron also readily reacts with hydrogen gas. These multiple effects work together to increase the hydrogen storage capacity and improve the convenience and safety of hydrogen storage and transportation. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a flowchart of an embodiment of the present invention.

[0018] Figure 2 These are the microstructure and elemental distribution diagrams of the material (before grinding) prepared in Example 1 of the present invention, wherein (a) is the microstructure, (b) is the elemental distribution, and the scale bar in (b) is also 20 μm.

[0019] Figure 3 The figure shows the PCT curve of the hydrogen storage material prepared in Example 1 of this invention at 298 K and a hydrogen pressure of 40 bar.

[0020] Figure 4 It is a hydrogen storage mechanism using solid-state materials.

[0021] Figure 5 The rod-shaped composite powders were prepared according to Comparative Examples 1-4.

[0022] Figure 6 The nanoscale composite powder after grinding in Example 1 of this invention.

[0023] Figure 7 The difference in average particle size of nanoparticles obtained by different proportions of hydrothermal reaction raw materials in the embodiments of the present invention is shown. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] Example 1,

[0026] A method for preparing hydrogen storage nano-titanium-based composite powder, such as Figure 1 As shown, it includes the following steps:

[0027] S1, ferric chloride hexahydrate (FeCl3·6H2O) and tetrabutyl titanate (C 16 H 36 O4Ti was added to distilled water at a mass ratio of 1:6 and stirred for a certain period of time to ensure complete dissolution and dispersion. After thorough mixing, anhydrous ethanol was added and stirred for 3 hours, then the pH of the solution was adjusted to 8-9. Ethanol is mainly used to dilute the water in the solution; ammonia is used to adjust the pH, and nitrogen can be decomposed and released in subsequent operations, improving product quality.

[0028] S2, the resulting mixture is transferred to a polytetrafluoroethylene-lined stainless steel container and hydrothermally reacted at 150°C for 16 hours to obtain the composite powder product.

[0029] S3 was washed with distilled water, the powder product was filtered, and after multiple filtrations and washes, it was dried at 60°C for 24 hours.

[0030] S4. The dried product was placed in a tube furnace and sintered at 800℃ for 2 hours under H2 atmosphere at a heating rate of 8℃ / min to achieve reduction of the obtained product. Then, it was placed in a stainless steel jar (1Cr18Ni9Ti) with stainless steel grinding balls at a ball-to-material volume ratio of 1:1. Grinding was carried out for 15 hours under nitrogen protection at a speed of 300 rpm, with the material filling 50% of the grinding jar volume, to obtain ultrafine (nano) titanium-iron (Ti / Fe) composite powder. The stainless steel jar and stainless steel balls were used to incorporate a small amount of iron or alloying elements during the grinding process, which facilitates the subsequent hydrogen adsorption and desorption of the titanium-iron composite powder.

[0031] Example 1 shows the relevant hydrogen storage characteristics of the nano-titanium-based composite powder prepared, such as... Figure 2 , Figure 3 As shown.

[0032] Figure 3 The black curve represents the hydrogen adsorption curve of the alloy, and the red curve represents the hydrogen desorption curve. It is clearly visible that the slope of the curve increases as the pressure rises to a certain level, indicating that the alloy begins to absorb hydrogen and continues to absorb it as the hydrogen concentration increases. When the rate of hydrogen absorption equals the rate of hydrogen release, the trend of the curve remains unchanged, forming an equilibrium point. This indicates that the alloy has reached saturation, and the rate of further hydrogen absorption will become very slow. The prepared material can achieve a hydrogen absorption capacity of 0.8 wt% at a hydrogen pressure of less than 1 MPa. In comparison, at the same temperature and hydrogen pressure, this material's hydrogen absorption rate and capacity are far superior to similar alloys. The hydrogen storage capacity reaches 1.2% at room temperature and low pressure.

[0033] Figure 6 The nanoscale titanium-iron composite powder prepared by the method described above exhibits a large specific surface area and numerous chemical vacancies, both of which are beneficial for hydrogen adsorption and storage. The average particle size was measured to be 15–25 nm, and the specific surface area was 400–500 m². 2 / g.

[0034] Example 2,

[0035] A method for preparing hydrogen storage nano-titanium-based composite powder includes the following steps:

[0036] S1, ferric chloride hexahydrate (FeCl3·6H2O) and tetrabutyl titanate (C 16 H 36 O4Ti) was added to distilled water at a mass ratio of 1:5 and stirred for a certain period of time to ensure complete dissolution and dispersion. After the mixture was homogeneous, anhydrous ethanol was added and stirred for 2 hours. Then, the pH of the solution was adjusted to 8-9 using ammonia.

[0037] S2, the resulting mixture is transferred to a TC4 (Ti6Al4V) titanium alloy reactor and hydrothermally reacted at 120℃ for 20 hours to obtain a composite powder product; taking advantage of the good corrosion resistance of titanium, it can also make up for the loss of titanium during the hydrothermal reaction and avoid excessive loss of titanium during subsequent filtration and washing.

[0038] S3 was washed with distilled water, the powder product was filtered, and after multiple filtrations and washes, it was dried at 50°C for 20 hours.

[0039] S4. The dried product was placed in a tube furnace and sintered at 750°C for 3 hours under H2 atmosphere at a heating rate of 10°C / min to achieve the reduction of the obtained product. Then it was placed in a stainless steel jar (1Cr18Ni9Ti). Stainless steel balls were used for grinding, with a ball-to-material volume ratio of 1:1.5. The product was ground for 20 hours under argon protection at a speed of 200 rpm. The loading amount was 40% of the grinding jar volume to obtain ultrafine (nano) titanium-iron (Ti / Fe) composite powder.

[0040] The ultrafine (nano) titanium-iron (Ti / Fe) composite powder obtained in Example 2 exhibited an irregular shape, with an average particle size of 10-20 nanometers and a specific surface area of ​​400-600 m². 2 / g, the measured hydrogen storage capacity is 2%.

[0041] Example 3,

[0042] A method for preparing hydrogen storage nano-titanium-based composite powder includes the following steps:

[0043] S1, ferric chloride hexahydrate (FeCl3·6H2O) and tetrabutyl titanate (C 16 H 36 O4Ti) was added to distilled water at a mass ratio of 1:7 and stirred for a certain period of time to ensure complete dissolution and dispersion. After the mixture was homogeneous, anhydrous ethanol was added and stirred for 2.5 hours. Then, the pH of the solution was adjusted to 8-9 using ammonia.

[0044] S2, the resulting mixture is transferred to a TC4 (Ti6Al4V) titanium alloy reactor and hydrothermally reacted at 130℃ for 18 hours to obtain a composite powder product; taking advantage of the good corrosion resistance of titanium, it can also make up for the titanium loss during the hydrothermal reaction and avoid excessive loss of titanium during subsequent filtration and washing.

[0045] S3 was washed with distilled water, the powder product was filtered, and after multiple filtrations and washes, it was dried at 55°C for 22 hours.

[0046] S4. The dried product was placed in a tube furnace and sintered at 780℃ for 2.5h at a heating rate of 9℃ / min under H2 atmosphere to achieve the reduction of the obtained product. Then it was placed in a stainless steel jar (1Cr18Ni9Ti) with stainless steel balls as the grinding balls and a ball-to-material volume ratio of 1:1.2. It was ground for 17 hours under argon protection at a speed of 260 rpm and the loading amount was 45% of the grinding jar volume to obtain ultrafine (nano) titanium-iron (Ti / Fe) composite powder.

[0047] The ultrafine (nano) titanium-iron (Ti / Fe) composite powder obtained in Example 3 exhibited an irregular shape, with an average particle size of 5-15 nanometers and a specific surface area of ​​500-700 m². 2 / g, the measured hydrogen storage capacity is 2%.

[0048] Comparative Example 1,

[0049] Ferric chloride hexahydrate (FeCl3·6H2O) and tetrabutyl titanate (C 16 H 36 O4Ti) was added to distilled water at a mass ratio of 1:1 and stirred for a certain period of time to ensure complete dissolution and dispersion. After the mixture was homogeneous, anhydrous ethanol was added and stirred for 3 hours, and then the pH of the solution was adjusted to 8-9.

[0050] The resulting mixture was transferred to a polytetrafluoroethylene-lined stainless steel container and hydrothermally reacted at 150°C for 3 hours to obtain the composite powder product.

[0051] Comparative Example 2,

[0052] Ferric chloride hexahydrate (FeCl3·6H2O) and tetrabutyl titanate (C 16 H 36 O4Ti) was added to distilled water at a mass ratio of 1:2 and stirred for a certain period of time to ensure complete dissolution and dispersion. After the mixture was homogeneous, anhydrous ethanol was added and stirred for 3 hours, and then the pH of the solution was adjusted to 8-9.

[0053] The resulting mixture was transferred to a polytetrafluoroethylene-lined stainless steel container and hydrothermally reacted at 150°C for 6 hours to obtain the composite powder product.

[0054] Comparative Example 3,

[0055] Ferric chloride hexahydrate (FeCl3·6H2O) and tetrabutyl titanate (C 16 H 36 O4Ti) was added to distilled water at a mass ratio of 1:3 and stirred for a certain period of time to ensure complete dissolution and dispersion. After the mixture was homogeneous, anhydrous ethanol was added and stirred for 3 hours, and then the pH of the solution was adjusted to 8-9.

[0056] The resulting mixture was transferred to a polytetrafluoroethylene-lined stainless steel container and hydrothermally reacted at 150°C for 9 hours to obtain the composite powder product.

[0057] Comparative Example 4,

[0058] Ferric chloride hexahydrate (FeCl3·6H2O) and tetrabutyl titanate (C 16 H 36 O4Ti) was added to distilled water at a mass ratio of 1:4 and stirred for a certain period of time to ensure complete dissolution and dispersion. After the mixture was homogeneous, anhydrous ethanol was added and stirred for 3 hours, and then the pH of the solution was adjusted to 8-9.

[0059] The resulting mixture was transferred to a polytetrafluoroethylene-lined stainless steel container and subjected to hydrothermal reaction at 150°C for 12 hours to obtain the composite powder product.

[0060] By adjusting the proportions of the hydrothermal reaction raw materials and the process parameters, composite powders of different shapes and sizes can be obtained. The structures of the composite powders obtained in Comparative Examples 1-4 are as follows: Figure 5 As shown, by changing the ratio of ferric chloride hexahydrate (FeCl3·6H2O) and tetrabutyl titanate, and by changing the hydrothermal reaction time, the powder changed from a short rod shape to a fibrous shape.

[0061] In the pursuit of high specific surface area in hydrogen storage alloys, in this embodiment of the invention, ferric chloride hexahydrate and tetrabutyl titanate are reacted at a mass ratio of 1:5~7 and the hydrothermal reaction time is 16~20h to obtain irregular composite powder particles; after high-temperature reduction and grinding, nano-sized irregular composite powder is obtained, which improves the corresponding hydrogen adsorption performance.

[0062] Comparative Example 5,

[0063] Only S1-S2 of Example 1 are performed, without S3-S4. The hydrothermal reaction crystallizes to form titanium and iron oxides, which are porous and sponge-like with relatively large particles and a hydrogen storage capacity of less than 1%.

[0064] Solid-state hydrogen storage materials contain numerous pores and voids, allowing hydrogen to dissolve into the solid and be adsorbed onto its surface and interior, forming physically adsorbed hydrogen. This further enhances the hydrogen storage capacity of the solid-state hydrogen storage material. During hydrogen storage and release, conditions such as temperature and pressure can be controlled to induce hydrogen adsorption and release, achieving the hydrogen storage function. Figure 4 As shown. Currently, the mechanism for solid-state hydrogen storage is still imperfect, and it remains unclear what kind of material should be prepared to achieve optimal hydrogen storage and release characteristics. Using a hydrothermal method, the prepared powder consists of an aggregate of numerous particles and voids between them. Typically, the void volume accounts for about 80%. Although these voids can store some hydrogen, the hydrogen stored in the voids is difficult to release.

[0065] This invention provides a method for obtaining porous, sponge-like nanoparticles with a large surface area using a hydrothermal method. Subsequent reduction treatment significantly reduces oxygen adsorption by the porous, sponge-like particles. Mechanical grinding further reduces particle size and increases lattice distortion, resulting in a sufficient number of lattice defects. Actual testing shows that the hydrogen storage capacity reaches 2%. The resulting composite powder does not require subsequent annealing, retaining the defects (vacancies, lattice distortion) present during hydrothermal processing and prolonged grinding, which is beneficial for hydrogen adsorption and storage. Furthermore, this invention includes the crucial element iron in addition to titanium. Iron improves the activation properties of titanium, making it easier to adsorb hydrogen. Iron is also an alloying element that readily reacts with hydrogen (absorbing and releasing hydrogen under certain conditions), and it is reasonably priced and easy to prepare. This invention uses a TC4 reactor in the hydrothermal reaction and stainless steel containers and balls with high alloying element content in the subsequent grinding process, aiming to further alloy the titanium-iron composite powder. These combined effects improve the convenience and safety of hydrogen storage and transportation, overcoming the shortcomings of existing technologies.

[0066] The hydrothermal process uses water as the reaction medium in a high-temperature, high-pressure reaction environment within an autoclave, allowing normally insoluble or poorly soluble substances to dissolve. The reaction can also facilitate recrystallization. Hydrothermal technology has two key characteristics: relatively low temperatures and the fact that it is conducted in a closed container, preventing component volatilization. Figure 7 The differences in nanoparticle size were obtained under the same process parameters (hydrothermal reaction at 120℃ for 18h) with different proportions of raw materials in the hydrothermal reaction. Figure 7 The mass ratios of raw materials (a) to (c) were 1:5, 1:10, and 1:20, respectively, and the average particle sizes of the obtained nanoparticles were 1.7, 5.5, and 7.3 nanometers, respectively. Figure 7 The hydrothermal reaction feedstock is LiOH·H2O (hydrated lithium hydroxide) and C8H 20 O4Si (dibutyl silicate) shows that many factors affect the hydrothermal reaction. Raw material ratio and process parameters all affect the particle size, surface area, and defect morphology of the powder, which greatly increases the difficulty of obtaining titanium-iron composite powder with excellent hydrogen storage performance.

[0067] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A method for preparing hydrogen storage nano-titanium-based composite powder, characterized in that, Includes the following steps: S1. Add ferric chloride hexahydrate and tetrabutyl titanate to distilled water at a mass ratio of 1:5~7, stir to dissolve and disperse them fully, add anhydrous ethanol after mixing evenly, stir evenly, and then adjust the pH of the solution to 8~9. S2, the resulting mixture is hydrothermally reacted at 120~150℃ for 16~20h to obtain the composite powder product; S3, wash with distilled water, filter the powder product, filter and wash multiple times, and then dry at 50~60℃ for 20~24h. S4. The dried product is placed in a tube furnace and sintered at 750-800℃ for 2-3 h at a heating rate of 8-10℃ / min under H2 atmosphere to reduce the product. Then, it is ground to obtain nano-titanium iron composite powder. In S1, ammonia is used to adjust the pH. In step S4, the ball-to-material volume ratio during grinding is 1:1 to 1.5, and the material loading is 40 to 50% of the grinding jar volume. In step S4, the grinding time is 15-20 hours and the rotation speed is 200-300 revolutions per minute.

2. The method for preparing a hydrogen storage nano-titanium-based composite powder according to claim 1, characterized in that, In step S1, anhydrous ethanol is added and the mixture is stirred for 2-3 hours.

3. The method for preparing a hydrogen storage nano-titanium-based composite powder according to claim 1, characterized in that, In S2, the reactor used is made of TC4 titanium alloy.

4. The method for preparing a hydrogen storage nano-titanium-based composite powder according to claim 1, characterized in that, In S4, the grinding jar is made of 1Cr18Ni9Ti stainless steel.

5. The method for preparing a hydrogen storage nano-titanium-based composite powder according to claim 1, characterized in that, In step S4, the grinding balls are made of stainless steel.

6. The method for preparing a hydrogen storage nano-titanium-based composite powder according to claim 1, characterized in that, In step S4, grinding is performed under nitrogen or argon protection.

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