A method for dehydrogenating light metal hydrides and applications thereof

Abstract

The application discloses a method for dehydrogenation of light metal hydride and application, and the method comprises the following steps: mixing raw materials containing light metal hydride and wave-absorbing materials under a protective atmosphere, and radiating microwaves to complete the dehydrogenation of the light metal hydride; the light metal hydride is selected from at least one of hydrides corresponding to metal elements in group I, group II and group III. The method for dehydrogenation of light metal hydride disclosed by the application has good response to microwave radiation after the mixed composite material, and the dehydrogenation temperature is significantly reduced compared with the thermal dehydrogenation temperature of the light metal hydride, so that the magnesium-based hydride can be completely dehydrogenated below 220 DEG C.

Description

Technical Field

[0001] This application relates to a method and application for dehydrogenation of light metal hydrides, belonging to the field of chemical catalyst preparation technology. Background Technology

[0002] Hydrogen energy is a new energy source that is abundant, clean, pollution-free, has high mass-energy density, and can be utilized in various forms. The large-scale application of hydrogen energy will have a significant impact on human society. Hydrogen storage materials have been a hot research topic in the energy field since their introduction in the 1860s. Light metal hydride hydrogen storage has advantages such as abundant sources, excellent reversible cycling, high hydrogen capacity, and mature preparation processes, and is considered one of the most likely hydrogen storage materials for large-scale hydrogen storage, transportation, and on-board hydrogen power in the future. Therefore, hydrogen storage technology based on light metal hydrides is expected to promote the large-scale application of hydrogen energy and is currently one of the hot research topics in the global hydrogen storage field.

[0003] However, due to the strong chemical bonds between metal and hydrogen in light metal hydrogen storage, light metal hydrides generally exhibit high thermal stability. Therefore, most light metal hydride dehydrogenation processes require maintaining high temperatures to complete. For example, magnesium hydride requires a high-temperature environment of around 350°C during dehydrogenation. Such extreme conditions hinder its practical application. Currently, methods such as nano-sizing, catalyst composites, and alloying have been developed to improve the thermal / kinetic performance of hydrogen storage, but the results are not satisfactory. Traditional thermal dehydrogenation methods suffer from low energy utilization, uneven heating, and are prone to phase separation and agglomeration in composite materials. These are all stumbling blocks hindering the further development of hydrogen metal hydrides.

[0004] Microwave radiation is a rapid, uniform, and energy-efficient external field, and is considered one of the most promising external fields for achieving gentle dehydrogenation of metal hydrides. However, metal hydrides with different dielectric properties respond differently to microwave radiation. A series of hydrides, represented by transition metal hydrides, can efficiently absorb microwave radiation and convert it into heat. However, these metal hydrides generally have low hydrogen storage capacity and high production costs, making them unsuitable for large-scale hydrogen storage systems. On the other hand, light metal hydrides, represented by magnesium hydride, have a very weak response to microwave radiation due to their own dielectric properties, and cannot efficiently utilize the energy of microwave radiation. Summary of the Invention

[0005] To overcome the shortcomings of existing dehydrogenation technologies and achieve efficient utilization of microwave radiation in light metal hydrides, thereby promoting the development and practical application of light metal hydrides, this invention proposes a method to enhance the auxiliary effect of microwave radiation on the dehydrogenation of light metal hydrides. This method is simple to operate; by mechanically combining light metal hydrides with a certain amount of microwave-absorbing material, the response of light metal hydrides to microwave radiation is significantly enhanced, achieving complete dehydrogenation under mild conditions while maintaining a high hydrogen storage capacity. This method has excellent applications in the construction of hydrogen storage systems. Furthermore, this method also shows great development prospects and practical application value in other application areas of metal hydrides.

[0006] According to one aspect of this application, a method for dehydrogenating light metal hydrides is provided, the method comprising: mixing raw materials containing light metal hydrides and microwave absorbing materials under a protective atmosphere, and then subjecting the mixture to microwave irradiation to complete the dehydrogenation of the light metal hydrides;

[0007] The light metal hydride is selected from at least one of the hydrides corresponding to metal elements in Group I, Group II, and Group III.

[0008] Optionally, the microwave absorbing material is selected from at least one of amorphous carbon, titanium hydride, vanadium hydride, iron oxide, silicon carbide, sodium borohydride, vanadium pentoxide, titanium oxide, molybdenum oxide, titanium dioxide, and titanium powder.

[0009] Optionally, the microwave absorbing material includes materials that can efficiently absorb microwave radiation and convert it into heat for release; and materials that cannot efficiently absorb microwave radiation on their own, but can react with metal hydrides and change their dielectric properties during mixing, thereby efficiently converting microwave energy into heat for release.

[0010] Optionally, the mass ratio of the light metal hydride to the microwave absorbing material is 1:0.01 to 1:1.

[0011] Optionally, the mass ratio of the light metal hydride to the microwave absorbing material is 1:0.1 to 1:0.5.

[0012] Optionally, the light metal hydride is selected from at least one of lithium hydride, sodium hydride, potassium hydride, magnesium hydride, calcium hydride, and aluminum hydride.

[0013] Optionally, the frequency of the microwave radiation is 0.3 GHz to 300 GHz.

[0014] Optionally, the frequency of the microwave radiation is selected from any value among 0.3GHz, 0.6GHz, 0.9GHz, 1GHz, 2GHz, 2.45GHz, 100GHz, 200GHz, and 300GHz, or a range between any two of the above points.

[0015] Optionally, the frequency of the microwave radiation is 2.45 GHz to 100 GHz.

[0016] Optionally, the frequency of the microwave radiation is selected from any value among 2.45 GHz, 5 GHz, 10 GHz, 20 GHz, 40 GHz, 60 GHz, 80 GHz, 90 GHz, and 100 GHz, or a range between any two of the above points.

[0017] Optionally, the protective atmosphere is selected from at least one of helium, neon, argon, krypton, and xenon.

[0018] Optionally, the protective atmosphere is selected from an argon atmosphere.

[0019] Optionally, the protective atmosphere is selected from inert gases such as helium (He), neon (Ne), argon (Ar), krypton (Kr), and xenon (Xe).

[0020] Optionally, the pressure of the protective atmosphere is 1 to 10 MPa.

[0021] Optionally, the pressure of the protective atmosphere is selected from any value of 1 MPa, 2 MPa, 3 MPa, 5 MPa, 7 MPa, 9 MPa, 10 MPa or a range between any two of the above points.

[0022] Optionally, the mixing is performed using ball milling and / or stirring.

[0023] Optionally, the ball milling conditions are: a ball milling temperature of 10–100°C, a ball milling speed of 50–600 rpm, and a ball milling time of 0.5–60 hours.

[0024] Optionally, the ball milling temperature is selected from any value among 10℃, 25℃, 50℃, 75℃, and 100℃, or a range between any two of the above points.

[0025] Optionally, the rotational speed of the ball mill is selected from any value among 50 rpm, 100 rpm, 200 rpm, 300 rpm, 400 rpm, 500 rpm, and 600 rpm, or a range between any two of the above.

[0026] Optionally, the ball milling time is selected from any value among 0.5 hours, 1 hour, 5 hours, 10 hours, 15 hours, 20 hours, 30 hours, 40 hours, 45 hours, 50 hours, and 60 hours, or a range between any two of the above points.

[0027] Optionally, the mass ratio of the ball mill media to the raw material is 20:1 to 120:1.

[0028] Optionally, the stirring conditions are: a stirring rate of 5000 to 30000 rpm and a stirring time of 2 to 20 hours.

[0029] Optionally, the stirring rate is selected from any value or range between any two points from 5000 rpm, 10000 rpm, 15000 rpm, 20000 rpm, 25000 rpm, and 30000 rpm.

[0030] Optionally, the stirring time is selected from any value of 2 hours, 5 hours, 10 hours, 15 hours, or 20 hours, or a range between any two points.

[0031] According to another aspect of this application, the application of the above method in a hydrogen storage system is provided.

[0032] The beneficial effects that this application can produce include:

[0033] (1) The present invention improves the microwave radiation response of light metal hydrides by mechanically combining hydrogen metal hydrides with microwave absorbing materials. This method is simple, easy to implement and easy to scale up.

[0034] (2) The method for enhancing the auxiliary effect of microwave radiation on the dehydrogenation of light metal hydrides provided by the present invention can significantly reduce the dehydrogenation temperature of light metal hydrides, achieve efficient dehydrogenation under mild conditions, and strongly promote the practical application of light metal hydrides.

[0035] (3) The present invention provides a method that combines the advantages of uniform microwave radiation heating and high energy utilization with the advantages of high hydrogen storage capacity and good cycle reversibility of light metal hydrides, providing a new idea for the design of novel hydrogen storage systems. Attached Figure Description

[0036] Figure 1 This is a graph showing the change in hydrogen signal in the sample during the dehydrogenation process of Example 1, as detected by mass spectrometry.

[0037] Figure 2 This is the XRD pattern of the sample after dehydrogenation in Example 1 of this application.

[0038] Figure 3 This refers to the change in hydrogen signal in the sample during the dehydrogenation process detected by mass spectrometry in Example 2 of this application.

[0039] Figure 4 This refers to the change in hydrogen signal in the sample during the dehydrogenation process detected by mass spectrometry in Example 5 of this application.

[0040] Figure 5 This refers to the change in hydrogen signal in the sample during the dehydrogenation process detected by mass spectrometry in Example 6 of this application.

[0041] Figure 6 This refers to the change in hydrogen signal in the sample during the dehydrogenation process detected by mass spectrometry in Example 7 of this application. Detailed Implementation

[0042] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0043] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.

[0044] The room temperature described in this application is 25°C.

[0045] The microwave-assisted dehydrogenation temperature is not limited to the temperature described in the examples.

[0046] In the embodiments of this application, the hydrogen content of the sample was measured using a commercially available volumetric high-pressure gas adsorption instrument (HPSA-auto type, China), and the hydrogen storage capacity was calculated using the modified Benedict-Webb-Rubin (MBWR) formula. Changes in the hydrogen signal during the dehydrogenation process were monitored using a mass spectrometer (HPR20, Hiden), and the phase composition of the dehydrogenated sample was characterized using an X'Pert3 powder X-ray diffractometer (XRD).

[0047] Example 1

[0048] In an argon-protected glove box, 2g of magnesium hydride and titanium dioxide were weighed out at a mass ratio of 1:0.25 and placed into a ball mill jar. The ball milling process was as follows: ball-to-material ratio of 100:1, at room temperature, under a 0.1MPa argon atmosphere, for 7 hours at a speed of 200 rpm, to obtain a composite material of titanium dioxide and magnesium hydride.

[0049] In an argon atmosphere, microwave radiation was applied to the obtained composite material. During the application process, the microwave radiation output power was changed and kept between 600 and 1200 W, and the reactant temperature was maintained at 220°C until complete dehydrogenation.

[0050] Figure 1 The change in hydrogen signal in the sample during the dehydrogenation process of Example 1 was detected by mass spectrometry. The hydrogen signal intensity increased by 4 orders of magnitude, proving that hydrogen was rapidly removed.

[0051] Figure 2 The XRD pattern of the sample after dehydrogenation in Example 1 shows only obvious diffraction peaks belonging to metallic magnesium, and no diffraction peaks belonging to magnesium hydride, proving that dehydrogenation was complete.

[0052] Example 2

[0053] In an argon-protected glove box, 2g of magnesium hydride and titanium dioxide were weighed out at a mass ratio of 1:0.25 and placed into a ball mill jar. The ball milling process was as follows: ball-to-material ratio of 100:1, at room temperature, under a 0.1MPa argon atmosphere, for 7 hours at a speed of 200 rpm, to obtain a composite material of titanium dioxide and magnesium hydride.

[0054] In an argon atmosphere, microwave radiation was applied to the obtained composite material, with the microwave radiation output power fixed at 1200W during the application process, until complete dehydrogenation.

[0055] Figure 3 The change in hydrogen signal in the sample during Example 2 was detected by mass spectrometry. The hydrogen signal intensity increased by 4 orders of magnitude, proving that hydrogen was rapidly released.

[0056] Example 3

[0057] In an argon-protected glove box, 2g of lithium hydride and titanium dioxide were weighed out at a mass ratio of 1:0.25 and placed into a ball mill jar. The ball milling process was as follows: ball-to-material ratio of 100:1, at room temperature, under a 0.1MPa argon atmosphere, for 7 hours at a speed of 200 rpm, to obtain a composite material of titanium dioxide and lithium hydride.

[0058] In an argon atmosphere, microwave radiation was applied to the obtained composite material, with the microwave radiation output power fixed at 1200W during the application process, until complete dehydrogenation.

[0059] Example 4

[0060] In an argon-protected glove box, 2g of sodium hydride and titanium dioxide were weighed out at a mass ratio of 1:0.2 and placed into a ball mill jar. The ball milling process was as follows: ball-to-material ratio of 100:1, at room temperature, under a 0.1MPa argon atmosphere, for 7 hours at a speed of 200 rpm, to obtain a composite material of titanium dioxide and sodium hydride.

[0061] In an argon atmosphere, microwave radiation was applied to the obtained composite material, with the microwave radiation output power fixed at 1200W during the application process, until complete dehydrogenation.

[0062] Example 5

[0063] In an argon-protected glove box, 2g of magnesium hydride and amorphous carbon material were weighed out at a mass ratio of 1:0.15 and placed into a ball mill jar. The ball milling process was as follows: ball-to-material ratio of 100:1, at room temperature, under a 0.1MPa argon atmosphere, for 7 hours at a speed of 200 rpm, to obtain a composite material of amorphous carbon material and magnesium hydride.

[0064] In an argon atmosphere, microwave radiation was applied to the obtained composite material. The microwave radiation output power was not fixed during the application process, and the temperature was fixed at 150℃, 160℃, and 170℃ respectively until complete dehydrogenation.

[0065] Figure 4 The change in hydrogen signal in the sample during Example 5 was detected by mass spectrometry. The hydrogen signal intensity increased by 4 orders of magnitude, proving that hydrogen was rapidly released.

[0066] Example 6

[0067] In an argon-protected glove box, 2g of magnesium hydride and titanium hydride materials were weighed out at a mass ratio of 1:0.1 and placed into a ball mill jar. The ball milling process was as follows: ball-to-material ratio of 100:1, at room temperature, under a 0.1MPa argon atmosphere, for 7 hours at a speed of 200 rpm, to obtain a composite material of titanium hydride and magnesium hydride.

[0068] In an argon atmosphere, the obtained composite material was subjected to microwave radiation at fixed temperatures of 250℃ and 310℃ until complete dehydrogenation.

[0069] Figure 5 The change in hydrogen signal in the sample during Example 6 was detected by mass spectrometry. The hydrogen signal intensity increased by 4 orders of magnitude, proving that hydrogen was rapidly released.

[0070] Example 7

[0071] In an argon-protected glove box, 2g of magnesium hydride and titanium powder were weighed in a mass ratio of 1:0.1 and placed into a ball mill jar. The ball milling process was as follows: ball-to-powder ratio of 100:1, at room temperature, under a 0.1MPa argon atmosphere, for 7 hours at a speed of 200 rpm, to obtain a composite material of titanium powder and magnesium hydride.

[0072] The resulting composite material was subjected to microwave radiation in an argon atmosphere at a fixed temperature of 310°C until complete dehydrogenation.

[0073] Figure 6 The change in hydrogen signal in the sample during Example 7 was detected by mass spectrometry. The hydrogen signal intensity increased by 4 orders of magnitude, proving that hydrogen was rapidly released.

[0074] Example 8

[0075] In an argon-protected glove box, 2g of sodium hydride and titanium powder were weighed out at a mass ratio of 1:0.3 and placed into a ball mill jar. The ball milling process was as follows: ball-to-powder ratio of 100:1, at room temperature, under a 0.1MPa argon atmosphere, for 10 hours at a speed of 250 rpm, to obtain a composite material of titanium powder and sodium hydride.

[0076] In an argon atmosphere, the obtained composite material was subjected to microwave radiation at a power of 1200W until complete dehydrogenation.

[0077] Example 9

[0078] In an argon-protected glove box, 2g of sodium hydride and silicon carbide were weighed out at a mass ratio of 1:0.2 and placed into a ball mill jar. The ball milling process was as follows: ball-to-material ratio of 100:1, at room temperature, under a 0.1MPa argon atmosphere, for 8 hours at a speed of 150 rpm, to obtain a composite material of silicon carbide and lithium hydride.

[0079] In an argon atmosphere, the obtained composite material was subjected to microwave radiation fixed at 1000W until complete dehydrogenation.

[0080] Example 10

[0081] In an argon-protected glove box, 2g of potassium hydride and vanadium pentoxide were weighed out at a mass ratio of 1:0.2 and placed into a ball mill jar. The ball milling process was as follows: ball-to-material ratio of 100:1, at room temperature, under a 0.1MPa argon atmosphere, for 6 hours at a speed of 200 rpm, to obtain a composite material of vanadium pentoxide and potassium hydride.

[0082] In an argon atmosphere, the obtained composite material was subjected to microwave radiation at a constant 1100W until complete dehydrogenation.

[0083] Comparative Example 1

[0084] In an argon-protected glove box, 2g of magnesium hydride was weighed and placed into a ball mill jar. The ball milling process was as follows: the ball-to-material ratio was 100:1, and the milling was carried out for 7 hours at 0.1MPa argon atmosphere at room temperature, with a rotation speed of 200 rpm, to obtain pure magnesium hydride material after milling.

[0085] In an argon atmosphere, microwave radiation was applied to the obtained composite material. During the application process, the output power of the microwave radiation was changed and kept between 600 and 1200 W. The temperature of the reactants was maintained at 220°C, and dehydrogenation was not possible.

[0086] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for dehydrogenating light metal hydrides, characterized in that, The method includes: mixing raw materials of light metal hydride and microwave absorbing material under a protective atmosphere, and then irradiating with microwaves to complete the dehydrogenation of light metal hydride; The light metal hydride is magnesium hydride; The microwave absorbing material is titanium dioxide; The mass ratio of the light metal hydride to the microwave absorbing material is 1:0.1 to 1:0.5; The frequency of the microwave radiation is 2.45 GHz to 100 GHz; The mixing is performed using ball milling. The ball milling conditions are as follows: the ball milling temperature is 10~100℃, the ball milling speed is 50~600 rpm, the ball milling time is 0.5~60 hours, and the mass ratio of the ball milling media to the raw material is 20:1~120:

1. The complete dehydrogenation temperature is 150℃, 160℃, 170℃ or 220℃.

2. The method according to claim 1, characterized in that, The protective atmosphere is selected from at least one of helium, neon, argon, krypton, and xenon.

3. The method according to claim 1, characterized in that, The pressure of the protective atmosphere is 1~10MPa.

4. The method according to claim 1, characterized in that, The mixing is performed by ball milling and / or stirring.

5. The method according to claim 4, characterized in that, The stirring conditions are: a stirring rate of 5000~30000 rpm and a stirring time of 2~20 hours.

6. The application of the method according to any one of claims 1 to 5 in a hydrogen storage system.

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