An Sb-doped Al-Ga based in-line hydrogen supply alloy for high flow rate hydrogen supply systems

Abstract

The application discloses an Sb-doped Al-Ga-based on-line hydrogen supply alloy for a large-flow hydrogen supply system. The application influences the hydrogen release performance of the alloy by controlling the doping amount of Sb in the alloy, changing the preferred growth orientation and grain size of Al grains in the alloy. Compared with the alloy without Sb doping, the hydrogen production alloy has a high yield of 92.68% at 30 DEG C. The average hydrogen production rate of the alloy at 60 DEG C is about 1.78 times that of the alloy without Sb doping. The price of the Sb-doped alloy is about 2000 yuan cheaper than that of the alloy without Sb doping per ton. The alloy can be used at a lower temperature, has a high yield, is cheap, can realize rapid hydrogen production in a large-power hydrogen supply system, and meets actual needs. The application has a great application prospect in the field of hydrogen production materials.

Description

Technical Field

[0001] This invention belongs to the field of online hydrogen supply technology through water electrolysis, specifically relating to an Sb-doped Al-Ga-based online hydrogen supply material with rapid water electrolysis hydrogen production performance at room temperature and its preparation method. Background Technology

[0002] Currently, with the increasing depletion of fossil fuels, hydrogen energy, as a new type of clean energy, has received widespread attention. In accelerating the promotion and application of hydrogen energy, finding safe, convenient, and low-cost storage and transportation technologies for hydrogen is one of the urgent problems to be solved. Among them, online hydrogen supply technology, represented by metal hydrolysis, has advantages such as low dependence on infrastructure and low storage and transportation costs, and is gradually showing great application potential.

[0003] To meet the needs of hydrogen fuel cells in practical applications, commonly used hydrogen production methods include: metal hydrolysis, biomass, and water electrolysis. However, these methods and materials all have limitations that restrict their development. Furthermore, the high cost of hydrogen refueling station construction and safety concerns during storage and transportation significantly limit hydrogen application. Among these methods, Al-based alloy hydrolysis offers advantages over others: the preparation method is relatively simple and suitable for large-scale production; hydrogen production can be achieved in a neutral water environment, and the hydrogen production rate can be controlled by adjusting the alloy's formulation; the hydrogen produced from the aluminum-water reaction has high purity; and the reaction is spontaneous, requiring no additional energy. However, Al is highly reactive and easily oxidized in air, forming a dense oxide film on its surface, which greatly limits its application. Common solutions include: spheroidizing Al with other substances to break down the surface oxide layer; reacting Al directly with acids and bases; and adding elements such as Ga, In, and Sn to Al. Compared with other methods of damaging the oxide film, the preparation of alloys by adding elements such as Ga, In, and Sn to Al overcomes the disadvantages of high energy consumption and demanding equipment requirements. To further improve the performance of such materials, related research continues to deepen. Previous studies have found that introducing refining agents such as Al2O3, Al-Ti-B, and Ti can change the morphology of Al grains in the alloy, thereby affecting the hydrogen production performance of the alloy to some extent. For example, CD Wei.; Z. Liu.; JL Wei.; D. Liu., etc. Chemical Physics Letters 2020, 738, pointed out that Al2O3 can be used as a refining agent for Al alloys. Al2O3 can accelerate the solidification rate of the alloy, resulting in a reduction in the grain and grain boundary particle size of the Al alloy. When the Al2O3 doping amount is 1.0 wt.%, the alloy exhibits the highest instantaneous hydrogen production rate and the shortest reaction time; however, as a refining agent, a relatively large amount of Al2O3 is required to achieve the grain refining effect. TTHe.; W.Wang.; DMChen.; K.Yang., International Journal of Hydrogen Energy 2014, (39), 684-691, pointed out that Al nucleation on TiAl3 will refine the Al grains. At 50℃, the hydrogen production rate of the alloy with a Ti content of 0.1wt.% is 50mL / gAl.BDDu.; W.Wang.; W.Chen.; DMChen.; K.Yang., International Journal of Hydrogen Energy 2017, (42), 21586-21596, pointed out that Al-Ti-B, as a grain refiner, reduced the grain size from 129 μm to 57 μm when the Ti content increased from 0.03 wt.% to 0.24 wt.%, and the hydrogen production rate was highest when the Ti content was 0.12 wt.%. However, although Ti and Al-Ti-B can reduce the grain size, Ti will form a Ti layer on the Al surface, occupying the sites of the Al-water reaction, which affects the rate and yield of the alloy. In summary, previous studies have shown that grain refinement in the alloy can promote the hydrogen decomposition rate of the material to a certain extent, but the improvement effect is poor. In particular, under normal operating conditions (below 40℃), the hydrogen production rate of the material is often not ideal, usually below 90%, which is difficult to meet the actual operating conditions.

[0004] This invention, through a first-time attempt to incorporate Sb into an Al-Ga-based alloy for hydrogen production, and then using a two-step method, obtains an Al-Ga-In-Sn-Sb hydrolysis hydrogen production alloy block. Under normal operating temperatures, the material exhibits excellent hydrogen production rates and energy conversion efficiency. Notably, compared to traditional grain refiners, Sb not only effectively reduces the aluminum grain size in the alloy, thus benefiting hydrogen production, but more importantly, unlike previous grain refiners, an appropriate amount of Sb can effectively reduce the alloy's hardness, making it easier to pulverize upon contact with water. This results in superior hydrogen production performance, solving the problem of rapid hydrogen production in high-power hydrogen supply systems while simultaneously reducing alloy material costs. This paper utilizes the fact that Sb-doped Al alloys act as sites for heterogeneous nucleation of Al grains to alter the size of Al grains. By controlling the Sb content in the alloy, Al grain refinement is achieved. Furthermore, the strong segregation of Sb on the Al surface reduces the surface energy of Al, increases dislocations and defects in the alloy, and decreases its mechanical properties, making it more prone to pulverization. Under the combined effect of these two mechanisms, the hydrogen production rate of the alloy is significantly improved, enabling rapid hydrogen production in practical applications. Moreover, the alloy has a wider operating temperature range, achieving a hydrogen production efficiency of over 90% even at 30℃. Summary of the Invention

[0005] This paper aims to invent an Al-Ga-In-Sn-Sb alloy with high hydrogen production rate and efficiency, and proposes a method for preparing this alloy. The preparation method of this invention differs from conventional melt-stirring casting. Due to the significant density difference between Al and Sb, and the relatively low Sb doping concentration, a two-step melt-stirring method is employed to ensure the uniformity of the alloy.

[0006] The preparation method of the hydrogen production alloy used is as follows:

[0007] Step 1. Grind the Al block to remove the oxide layer on the surface, weigh it, and place it in an alumina crucible. Then weigh a certain mass of Sb element and add it to the crucible containing the Al block. The mass ratio of Sb varies in the range of 0.05-0.2.

[0008] Step 2. Place the crucible containing Al and Sb in a box-type atmosphere stirring furnace, evacuate, and heat to melt under nitrogen protection. Raise the temperature uniformly from room temperature to above 650℃, hold for 0.5-1 hour, stir at a rate of 20-50 r / min, and the total stirring time should not exceed 20 minutes. Pour the mixture into a mold preheated to 200-400℃.

[0009] Step 3. Place the prepared Al-Sb alloy in a high-alumina crucible and add Ga, In, and Sn. The mass ratio of Ga varies from 6.7% to 6.85%, the mass ratio of In varies from 2.1% to 2.15%, and the mass ratio of Sn varies from 0.98% to 1%.

[0010] Step 4. Place the weighed Ga, In, and Sn elements, along with the prepared Al-Sb alloy, into a crucible and place it in a high-temperature atmosphere stirred furnace. First, evacuate the furnace for about 10 minutes, then introduce nitrogen gas and evacuate again to fill the entire furnace chamber with nitrogen. Under the nitrogen protective atmosphere, heat the alloy to 700-900℃ at a uniform heating rate of 8-12℃ / min, and hold for about 1 hour to completely melt the alloy. Then, stir at a rate of 30 r / min for 10-15 minutes.

[0011] Step 5: Pour the molten and stirred alloy into a preheated mold. The mold temperature should not be lower than 300℃. Cool at room temperature and seal with sealing film to prevent oxidation.

[0012] Another object of the present invention is to provide the application of the above-mentioned highly active aluminum alloy in the field of hydrogen production.

[0013] The beneficial effects of this invention are as follows:

[0014] (1) This invention provides a highly active aluminum alloy for hydrogen production. In the aforementioned aluminum alloy hydrogen production material, Sb acts as a site for heterogeneous nucleation of Al grains, refining the grain size, reducing the size of Al grains, and changing the orientation of the preferred growth of Al grains in the alloy, causing the Al grains to grow uniformly along the (111) plane instead of the (111) plane. Compared with other grain refiners, Sb has a better grain refinement effect on Al, requiring only 0.1 wt.% to achieve the best effect; and the segregation of Sb on the Al surface increases the bonding energy at the Al interface, making the alloy more brittle. During hydrogen production, the bulk alloy is more likely to decompose into fine particles, further promoting the hydrolysis reaction. However, the grain refinement effect of Sb in the Al alloy is saturated. When the Sb content is too high, it will form intermetallic compounds such as AlSb, InSb, and SnSb with Al, In, Sn, etc., reducing the Sb content as a site for heterogeneous nucleation of Al grains.

[0015] (2) The alloy of the present invention has excellent hydrogen production performance and a wide range of applications. At 30°C, its aluminum production can reach over 90%, and at 60°C, its hydrogen production rate can reach 283.83%.

[0016] The rate (mL / (min·g)) is 1.78 times that of the alloy without Sb. Furthermore, the addition of Sb reduces the amount of Ga, In, and Sn required, thus lowering the cost of the alloy to some extent. The sample with 0.1 wt.% Sb doping is 1400 yuan cheaper per ton than the sample without Sb.

[0017] (3) The preparation method of the aluminum alloy hydrogen production material provided by the present invention is relatively simple, inexpensive, and can be used for large-scale production.

[0018] In summary, this invention provides a highly reactive aluminum-gallium hydrogen production material. It is the first to use Sb as a grain refiner in hydrogen production alloys, and by utilizing the strong segregation of Sb on the Al surface, the alloy exhibits reduced grain size and decreased hardness, making it easier to pulverize during hydrogen production and further promoting the hydrolysis reaction. This has significant implications for high-power online hydrogen supply systems. Attached Figure Description

[0019] Figure 1 This is a flowchart of the present invention.

[0020] Figure 2 This is a diagram illustrating the hydrogen production performance testing method of the present invention.

[0021] Figure 3 The images show the XRD curves of alloy blocks with different formulations in the embodiments of the present invention.

[0022] Figure 4The images shown are SEM images of alloy blocks with different formulations in the embodiments of the present invention.

[0023] Figure 5 The hydrogen production performance curves of alloy blocks with different formulations in the embodiments of the present invention at 30°C are shown.

[0024] Figure 6 The hydrogen production performance curves of alloy blocks with different formulations in the embodiments of the present invention at 60°C are shown. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and examples, but the scope of the present invention is not limited to the examples below.

[0026] Example 1: Weigh 18g of aluminum and 0.01g of antimony into a crucible. Place the crucible in a box-type atmosphere stirring furnace and, under nitrogen protection, uniformly heat to 800℃ at a rate of 11℃ / min and hold for 1 hour. Then, stir uniformly at a rate of 30r / min for 10 minutes. Pour the molten alloy into a mold preheated to 300℃ and allow it to cool naturally before sealing with a sealing film. Place the sintered aluminum-antimony alloy into a crucible, add 1.3632g of Ga, 0.4278g of In, and 0.199g of Sn. Place the crucible in a box-type atmosphere stirring furnace and repeat the above steps to obtain the desired Al-Ga-In-Sn-Sb alloy.

[0027] Example 2: Weigh 18g of aluminum and 0.0g of antimony into a crucible. Place the crucible in a box-type atmosphere stirring furnace and, under nitrogen protection, uniformly heat to 800℃ at a rate of 11℃ / min and hold for 1 hour. Then, stir uniformly at a rate of 30r / min for 10 minutes. Pour the molten alloy into a mold preheated to 300℃ and allow it to cool naturally before sealing with a sealing film. Place the sintered aluminum-antimony alloy into a crucible, add 1.3564g of Ga, 0.4436g of In, and 0.198g of Sn. Place the crucible in a box-type atmosphere stirring furnace and repeat the above steps to obtain the desired Al-Ga-In-Sn-Sb alloy.

[0028] Example 3: Weigh 18g of aluminum and 0.03g of antimony into a crucible. Place the crucible in a box-type atmosphere stirring furnace and, under nitrogen protection, uniformly heat to 800℃ at a rate of 11℃ / min and hold for 1 hour. Then, stir uniformly at a rate of 30r / min for 10 minutes. Pour the molten alloy into a mold preheated to 300℃ and allow it to cool naturally before sealing with a sealing film. Place the sintered aluminum-antimony alloy into a crucible, add 1.3494g of Ga, 0.4236g of In, and 0.197g of Sn. Place the crucible in a box-type atmosphere stirring furnace and repeat the above steps to obtain the desired Al-Ga-In-Sn-Sb alloy.

[0029] Example 4: Weigh 18g of aluminum and 0.02g of antimony into a crucible. Place the crucible in a box-type atmosphere stirring furnace and, under nitrogen protection, uniformly heat to 800℃ at a rate of 11℃ / min and hold for 1 hour. Then, stir uniformly at a rate of 30r / min for 10 minutes. Pour the molten alloy into a mold preheated to 300℃ and allow it to cool naturally before sealing with a sealing film. Place the sintered aluminum-antimony alloy into a crucible, add 1.3426g of Ga, 0.4214g of In, and 0.196g of Sn. Place the crucible in a box-type atmosphere stirring furnace and repeat the above steps to obtain the desired Al-Ga-In-Sn-Sb alloy.

[0030] Comparative Example: We used a sample without added Sb as a comparative example. Weigh 18g Al, 1.37g Ga, 0.43g In, and 0.2g Sn into a high-alumina crucible. Place the crucible in a box-type atmosphere stirring furnace and heat it to 800℃ at a rate of 11℃ / min under nitrogen protection. Hold the temperature for 1 hour, then stir it at a rate of 30r / min for 10 minutes. Pour the molten alloy into a mold preheated to 300℃. After natural cooling, seal it with sealing film for later use.

[0031] Example 5: To evaluate the hydrogen production performance of the Sb-doped aluminum gallium-based alloy, we studied Examples 1-4 and the comparative examples using the water displacement method. We used approximately 0.32 g of sample and a water bath to simulate a constant temperature environment, testing the hydrogen release performance of the alloy at 30°C and 60°C. The mass of the discharged water was recorded every 0.03 s using a computer, allowing for the measurement of the average hydrogen release rate and yield of the alloy. All examples and comparative examples reacted immediately upon contact with water. The evaluation of alloy performance mainly included the average hydrogen production rate and yield. The highly active aluminum gallium-based hydrogen production alloy prepared according to Example 2 achieved a hydrogen production efficiency of 92.68% at 30°C, while the comparative example's yield was only 75.81%. Furthermore, the highly active aluminum gallium-based hydrogen production alloy prepared according to Example 2 achieved an average hydrogen production rate of 45.36 (mL / (g·min)) at 30°C, while the comparative example's average hydrogen production rate was only 21.14 (mL / (g·min)). The highly active aluminum-gallium-based hydrogen production alloy prepared according to Example 2 achieved a hydrogen production efficiency of 97.18% at 60°C, compared to 91.24% in the comparative example. Furthermore, the highly active aluminum-gallium-based hydrogen production alloy prepared according to Example 2 achieved an average hydrogen production rate of 283.83 mL / (g·min) at 60°C, while the average hydrogen production rate in the comparative example was only 159.54 mL / (g·min). According to... Figure 5 and Figure 6 The hydrogen production performance of Examples 1-4 and the comparative examples at 30 and 60°C showed significant differences, as shown in Tables 1 and 2.

[0032] Table 1. Hydrogen production performance at 30°C for Examples 1-4 and Comparative Examples.

[0033]

[0034] Table 2 shows the hydrogen production performance at 60°C for Examples 1-4 and the comparative examples.

[0035]

[0036] To investigate this difference, we performed XRD and SEM tests on the examples and comparative examples. We found that, compared to the comparative example, the preferred growth orientation of the Al grains in the examples changed, from preferred growth along the Al(111) plane to uniform growth along both the (111) and (200) planes. Further SEM testing of the alloy, consistent with the XRD data, showed that the Al grains changed from columnar to short rod-shaped, and the grain size significantly decreased. Figure 3 and Figure 4 As can be clearly seen, the grain size variation is shown in Table 3.

[0037] Table 3 Grain sizes of Examples 1-4 and Comparative Examples

[0038]

[0039] Although Sb doping reduces the grain size of the alloy, the strong segregation of Sb on the Al surface makes the alloy brittle, and the hardness of the alloy decreases instead, as shown in Table 4.

[0040] Table 4 Hardness of Examples 1-4 and Comparative Examples

[0041]

Claims

1. An Sb-doped Al-Ga-based in-situ hydrogen supply alloy for high-flow-rate hydrogen supply systems, characterized in that: Sb was added to an Al-Ga-In-Sn alloy used for hydrogen production via hydrolysis using a two-step method. After homogenization of the alloy components, the alloy was cast at 300°C to obtain an aluminum-gallium-based alloy for hydrogen production via hydrolysis. The Sb refining agent accounted for 0.01-0.2 wt.% of the alloy by weight; the total weight ratio of Ga, In, and Sn was 9.99 wt.%-9.8 wt.%. The proportion of Al is 90 wt.%, the mass ratio of Ga is 6.7-6.85%, the mass ratio of In is 2.1-2.15%, the mass ratio of Sn is 0.98-1%, and the total mass of Al-Ga-In-Sn-Sb is 100%. The method for preparing an Sb-doped Al-Ga-based in-situ hydrogen supply alloy for a high-flow-rate hydrogen supply system includes the following steps: (1) While ensuring that the content of Al in the alloy remains unchanged and the mass ratio of Ga, In and Sn remains unchanged, the amount of Sb doping is changed. In order to ensure the uniformity of each component in the alloy, we adopt the indirect melting method, that is, first put Al and Sb into a crucible, put it into a box-type atmosphere stirring furnace, turn on the vacuum pump, evacuate the vacuum, and then sinter under the protective atmosphere of nitrogen. (2) After the box-type atmosphere mixing furnace is heated to above 650℃, it is kept at the temperature for 0.5-1h, and after stirring for 10-20min, it is poured into a mold preheated to 200-400℃. (3) Weigh the remaining three elements according to the proportion and place them together with the Al-Sb alloy prepared in advance in a crucible and place it in a high-temperature atmosphere stirring furnace; first, evacuate for 10 minutes, then introduce nitrogen and evacuate again to fill the entire furnace with nitrogen; under the nitrogen protective atmosphere, heat the alloy to 700-900℃, heat at a rate of 8-12℃ / min, hold for 1 hour to completely melt the alloy, and stir at a rate of 30r / min for no more than 15 minutes. (4) The molten and stirred alloy is poured into a preheated mold. The mold temperature is not lower than 300°C. The alloy is cooled at room temperature and sealed with a sealing film to prevent oxidation.

2. The hydrogen-donating alloy according to claim 1, in which Sb-doped samples all exhibit reduced grain size, and the Sb-doped Al-Ga-In-Sn-Sb alloy is characterized by, The grain size of the hydrogen-donating alloy is no greater than 50 μm.

3. The hydrogen-donating alloy according to claim 2, where Sb doping degrades the mechanical properties of the sample and makes it prone to pulverization during the reaction, is characterized by the following: The Al-Ga-In-Sn-Sb alloy prepared by Sb doping... The hydrogen-donating alloy has a hardness of less than 0.3 GPa.

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