A hydrogen storage material with high hydrogen production rate and preparation method thereof

Abstract

The present invention relates to the technical field of solid-state hydrogen storage materials, and in particular to a hydrogen storage material with a high hydrogen production rate and a preparation method thereof. The present invention mixes magnesium hydride and carbon layer-modified montmorillonite nanosheets in an organic solvent, and then sequentially vacuum-dries and solid-phase ball-mills to obtain a hydrogen storage material with a high hydrogen production rate. The carbon layer-modified montmorillonite nanosheets are obtained by hydrothermal reaction after montmorillonite is modified by intercalation and exfoliation of 1,2,4-triaminoaniline dihydrochloride. The hydrogen storage material with a high hydrogen production rate provided by the present invention has excellent hydrogen storage capacity and hydrogen production rate, and is not easily passivated in an air environment, which is significantly improved compared to commercially available magnesium hydride.

Description

Technical Field

[0001] The present invention relates to the technical field of solid hydrogen storage materials, and in particular to a hydrogen storage material with a high hydrogen production rate and a preparation method thereof. Background Art

[0002] Energy is an essential part of our daily lives and is required for almost all human activities. Fossil fuels such as oil, natural gas and coal provide more than 80% of all energy consumed worldwide. However, the use of these fossil fuels leads to greenhouse gas emissions. Hydrogen energy is considered to be a potential low-cost clean fuel in the future economy. In the development of the hydrogen economy, the extremely low hydrogen density makes hydrogen storage a technical problem that needs to be solved. In its natural state, hydrogen is volatile and highly flammable, which also makes it more difficult to transport. Improving hydrogen storage density is a key technology.

[0003] Magnesium hydride has high volumetric hydrogen storage capacity and high mass hydrogen storage capacity (mass hydrogen storage density is 7.6wt%, volume hydrogen storage density is 110kg / m 3 ) has become a promising hydrogen storage material. In addition, this light metal is cheap and abundant, with a content of 0.13wt% in seawater and 2.76wt% in the earth's crust, which is almost inexhaustible. However, the application of magnesium as a hydrogen storage medium has been long restricted due to the inherent disadvantages of magnesium hydride, namely poor thermodynamic properties and slow absorption and desorption kinetics, which are attributed to its high desorption enthalpy and the low diffusion coefficient of H in bulk Mg in the absence of a catalyst; in addition, the magnesium surface is easily passivated when exposed to air.

[0004] Patent technology document CN202111620801.4 discloses a hydrogen storage material doped with nano Ni-Nb-O and magnesium hydride, which is prepared by mechanical ball milling of magnesium hydride and nano Ni-Nb-O; the nano Ni-Nb-O is first prepared by a solvent thermal method using a soluble niobium source as a precursor, and then prepared by a calcination method; the microscopic morphology of the nano Ni-Nb-O is a large particle agglomerated from nanoparticles of 50-100nm, with a specific surface area of ​​16.05-19.38 m2. Although Ni-Nb-O effectively improves the hydrogen storage capacity and hydrogen production efficiency of magnesium hydride, niobium is a rare metal with low reserves and high price, which cannot meet actual needs and needs further improvement. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a hydrogen storage material with a high hydrogen production rate and a preparation method thereof, so as to improve the hydrogen storage capacity and hydrogen production rate of magnesium hydride and effectively solve the problem of easy passivation when exposed to air.

[0006] Based on the above purpose, the present invention provides a method for preparing a hydrogen storage material with a high hydrogen production rate, comprising the following steps: mixing magnesium hydride and carbon layer modified montmorillonite nanosheets in an organic solvent, and then vacuum drying and solid phase ball milling to obtain a hydrogen storage material with a high hydrogen production rate.

[0007] Furthermore, the weight ratio of the magnesium hydride, the carbon layer modified montmorillonite nanosheets and the organic solvent is 10:1-2:50-100.

[0008] Furthermore, the preparation method of the carbon layer modified montmorillonite nanosheets is as follows:

[0009] S1: Add 1,2,4-triaminoaniline dihydrochloride to a hydrochloric acid aqueous solution, dissolve it by ultrasonication, then add montmorillonite and deionized water, stir at 60-70°C for 3-4h, wash, and dry to obtain modified montmorillonite;

[0010] S2: Dispersing the modified montmorillonite in anhydrous ethanol, transferring to an autoclave, reacting at 180-200° C. for 12-15 hours, washing, centrifuging, and drying to obtain carbon layer-modified montmorillonite nanosheets.

[0011] Furthermore, an anionic surfactant is added to the organic solvent.

[0012] Preferably, the anionic surfactant is added in an amount of 3-5% by weight of magnesium hydride.

[0013] More preferably, the anionic surfactant is added in an amount of 4% by weight of magnesium hydride.

[0014] Preferably, the anionic surfactant is sodium dodecylbenzenesulfonate or sodium hexadecylbenzenesulfonate.

[0015] Preferably, the organic solvent is one of anhydrous toluene, cyclohexane and heptane.

[0016] More preferably, the organic solvent is anhydrous toluene.

[0017] Preferably, the ball-to-material ratio of the solid phase ball milling treatment is 30:1-2, the ball milling speed is 1000-1200 r / min, and the ball milling time is 4-8 h.

[0018] Preferably, in step S1, the weight ratio of 1,2,4-triaminoaniline dihydrochloride, aqueous hydrochloric acid solution, montmorillonite and deionized water is 0.3-0.5:40-50:2-3:150-200;

[0019] Preferably, in step S2, the weight ratio of modified montmorillonite to anhydrous ethanol is 2-3:50-100.

[0020] Furthermore, the present invention also provides a hydrogen storage material with a high hydrogen production rate, which is obtained according to the preparation method of the hydrogen storage material with a high hydrogen production rate.

[0021] Beneficial effects of the present invention:

[0022] The hydrogen storage material with high hydrogen production rate provided by the present invention is obtained by compounding magnesium hydride and carbon layer modified montmorillonite nanosheets, wherein the carbon layer modified montmorillonite nanosheets are obtained by hydrothermal reaction after montmorillonite is modified by intercalation stripping of 1,2,4-triaminoaniline dihydrochloride, the montmorillonite after intercalation stripping has a sheet structure and has rich charges on the surface, the 1,2,4-triaminoaniline dihydrochloride adsorbed on the surface can be further converted into a carbon layer by hydrothermal reaction, and the formed montmorillonite nanosheets covered with a uniform carbon layer can effectively improve the hydrogen storage performance of magnesium hydride, improve the hydrogen absorption and desorption efficiency, reduce the reaction barrier, and reduce the degree of passivation when exposed to air after ball milling with magnesium hydride.

[0023] The invention provides a hydrogen storage material with a high hydrogen production rate. An anionic surfactant is added to a mixture of carbon layer-modified montmorillonite nanosheets and magnesium hydride. The anionic surfactant can be adsorbed on the surface of the carbon layer-modified montmorillonite nanosheets to improve its protective effect on magnesium hydride and further reduce the passivation degree of the hydrogen storage material when exposed to air. It is unexpectedly found that the anionic surfactant helps to increase the hydrogen absorption and desorption rate and reduce the kinetic barrier. This may be because the anionic surfactant promotes the dispersion of the carbon layer-modified montmorillonite nanosheets on the surface of magnesium hydride, so that the carbon layer and the magnesium hydride have a higher contact area, thereby improving the catalytic effect. DETAILED DESCRIPTION

[0024] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0025] The montmorillonite in the specific embodiment of the present invention was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. with a product number of M109698; magnesium hydride was purchased from Guangdong Wengjiang Chemical Reagent Co., Ltd. with a product number of WA00659.

[0026] Example 1: A method for preparing a hydrogen storage material with a high hydrogen production rate:

[0027] S1: 0.3 g of 1,2,4-triaminoaniline dihydrochloride was added to 40 g of 1 mol / L hydrochloric acid aqueous solution, and ultrasonically dissolved. Then, 2 g of montmorillonite and 150 g of deionized water were added, and the mixture was stirred at 60° C. for 3 h, washed, and dried to obtain modified montmorillonite.

[0028] S2: 2 g of modified montmorillonite was dispersed in 50 g of anhydrous ethanol, transferred to an autoclave, reacted at 180°C for 15 h, washed, centrifuged, and dried to obtain carbon layer-modified montmorillonite nanosheets.

[0029] S3: 10g of magnesium hydride and 1g of carbon layer modified montmorillonite nanosheets were mixed in 50g of cyclohexane, and then vacuum dried and solid phase ball milled in sequence, with a ball-to-material ratio of 30:1, a ball milling speed of 1000r / min, and a ball milling time of 8h to obtain a hydrogen storage material with a high hydrogen production rate.

[0030] Example 2: A method for preparing a hydrogen storage material with a high hydrogen production rate:

[0031] S1: 0.4 g of 1,2,4-triaminoaniline dihydrochloride was added to 45 g of 1 mol / L hydrochloric acid aqueous solution, and ultrasonically dissolved. Then, 2.5 g of montmorillonite and 180 g of deionized water were added, and the mixture was stirred at 65° C. for 3 h, washed, and dried to obtain modified montmorillonite.

[0032] S2: 2.5 g of modified montmorillonite was dispersed in 80 g of anhydrous ethanol, transferred to an autoclave, reacted at 180°C for 14 h, washed, centrifuged, and dried to obtain carbon layer-modified montmorillonite nanosheets.

[0033] S3: 10g of magnesium hydride and 1.5g of carbon layer modified montmorillonite nanosheets were mixed in 80g of anhydrous toluene, and then vacuum dried and solid phase ball milled in sequence, with a ball-to-material ratio of 30:1.5, a ball milling speed of 1100r / min, and a ball milling time of 6h to obtain a hydrogen storage material with a high hydrogen production rate.

[0034] Example 3: A method for preparing a hydrogen storage material with a high hydrogen production rate:

[0035] S1: 0.5 g of 1,2,4-triaminoaniline dihydrochloride was added to 50 g of 1 mol / L hydrochloric acid aqueous solution, and ultrasonically dissolved. Then, 3 g of montmorillonite and 200 g of deionized water were added, and the mixture was stirred at 70° C. for 4 h, washed, and dried to obtain modified montmorillonite.

[0036] S2: 3 g of modified montmorillonite was dispersed in 100 g of anhydrous ethanol, transferred to an autoclave, reacted at 200° C. for 15 h, washed, centrifuged, and dried to obtain carbon layer-modified montmorillonite nanosheets.

[0037] S3: 10g of magnesium hydride and 2g of carbon layer modified montmorillonite nanosheets were mixed in 100g of anhydrous toluene, and then vacuum dried and solid phase ball milled in sequence, with a ball-to-material ratio of 30:2, a ball milling speed of 1200r / min, and a ball milling time of 8h to obtain a hydrogen storage material with a high hydrogen production rate.

[0038] Example 4: A method for preparing a hydrogen storage material with a high hydrogen production rate:

[0039] S1: 0.4 g of 1,2,4-triaminoaniline dihydrochloride was added to 45 g of 1 mol / L hydrochloric acid aqueous solution, and ultrasonically dissolved. Then, 2.5 g of montmorillonite and 180 g of deionized water were added, and the mixture was stirred at 65° C. for 3 h, washed, and dried to obtain modified montmorillonite.

[0040] S2: 2.5 g of modified montmorillonite was dispersed in 80 g of anhydrous ethanol, transferred to an autoclave, reacted at 180°C for 14 h, washed, centrifuged, and dried to obtain carbon layer-modified montmorillonite nanosheets.

[0041] S3: 10g magnesium hydride, 1.5g carbon layer modified montmorillonite nanosheets and 0.3g sodium dodecylbenzene sulfonate were mixed in 80g anhydrous toluene, and then vacuum dried and solid phase ball milled in sequence, with a ball-to-material ratio of 30:1.5, a ball milling speed of 1100r / min, and a ball milling time of 6h to obtain a hydrogen storage material with a high hydrogen production rate.

[0042] Example 5: A method for preparing a hydrogen storage material with a high hydrogen production rate:

[0043] S1: 0.4 g of 1,2,4-triaminoaniline dihydrochloride was added to 45 g of 1 mol / L hydrochloric acid aqueous solution, and ultrasonically dissolved. Then, 2.5 g of montmorillonite and 180 g of deionized water were added, and the mixture was stirred at 65° C. for 3 h, washed, and dried to obtain modified montmorillonite.

[0044] S2: 2.5 g of modified montmorillonite was dispersed in 80 g of anhydrous ethanol, transferred to an autoclave, reacted at 180°C for 14 h, washed, centrifuged, and dried to obtain carbon layer-modified montmorillonite nanosheets.

[0045] S3: 10g of magnesium hydride, 1.5g of carbon layer modified montmorillonite nanosheets and 0.4g of sodium dodecylbenzene sulfonate were mixed in 80g of anhydrous toluene, and then vacuum dried and solid phase ball milled in sequence, with a ball-to-material ratio of 30:1.5, a ball milling speed of 1100r / min, and a ball milling time of 6h to obtain a hydrogen storage material with a high hydrogen production rate.

[0046] Example 6: A method for preparing a hydrogen storage material with a high hydrogen production rate:

[0047] S1: 0.4 g of 1,2,4-triaminoaniline dihydrochloride was added to 45 g of 1 mol / L hydrochloric acid aqueous solution, and ultrasonically dissolved. Then, 2.5 g of montmorillonite and 180 g of deionized water were added, and the mixture was stirred at 65° C. for 3 h, washed, and dried to obtain modified montmorillonite.

[0048] S2: 2.5 g of modified montmorillonite was dispersed in 80 g of anhydrous ethanol, transferred to an autoclave, reacted at 180°C for 14 h, washed, centrifuged, and dried to obtain carbon layer-modified montmorillonite nanosheets.

[0049] S3: 10g of magnesium hydride, 1.5g of carbon layer modified montmorillonite nanosheets and 0.5g of sodium hexadecylbenzenesulfonate were mixed in 80g of anhydrous toluene, and then vacuum dried and solid phase ball milled in sequence, with a ball-to-material ratio of 30:1.5, a ball milling speed of 1100r / min, and a ball milling time of 6h to obtain a hydrogen storage material with a high hydrogen production rate.

[0050] Comparative Example 1:

[0051] S1: 0.4 g of 1,2,4-triaminoaniline dihydrochloride was added to 45 g of 1 mol / L hydrochloric acid aqueous solution, and ultrasonically dissolved. Then, 2.5 g of montmorillonite and 180 g of deionized water were added, and the mixture was stirred at 65° C. for 3 h, washed, and dried to obtain modified montmorillonite.

[0052] S2: 10 g of magnesium hydride and 1.5 g of modified montmorillonite were mixed in 80 g of anhydrous toluene, and then vacuum dried and solid-phase ball milled in sequence, with a ball-to-material ratio of 30:1.5, a ball milling speed of 1100 r / min, and a ball milling time of 6 h to obtain a hydrogen storage material.

[0053] Comparative Example 2:

[0054] 10g of magnesium hydride and 1.5g of montmorillonite were mixed in 80g of anhydrous toluene, and then vacuum dried and solid-phase ball milled in sequence, with a ball-to-material ratio of 30:1.5, a ball milling speed of 1100r / min, and a ball milling time of 6h to obtain a hydrogen storage material with a high hydrogen production rate.

[0055] Comparative Example 3:

[0056] 10 g of magnesium hydride was mixed with 80 g of anhydrous toluene, and then vacuum dried and solid-phase ball milled in sequence, with a ball-to-material ratio of 30:1.5, a ball milling speed of 1100 r / min, and a ball milling time of 6 h to obtain a hydrogen storage material with a high hydrogen production rate.

[0057] Performance Test:

[0058] Isothermal hydrogen absorption and desorption test: The hydrogen storage materials prepared in the embodiments and comparative examples were subjected to isothermal hydrogen absorption and desorption test. 100 mg of each sample was placed in a stainless steel sample chamber in a glove box filled with argon. The initial hydrogen pressures of the hydrogen absorption and desorption measurements were 3.0 MPa and 0.005 MPa, respectively. Isothermal hydrogen desorption curves at 275°C, 300°C, 325°C, and 350°C were obtained, and the apparent activation energy Ea of the reaction was obtained by fitting the isothermal hydrogen desorption curves at different temperatures. The test results are shown in Table 1.

[0059] Passivation experiment in air: The hydrogen storage materials prepared in the examples and comparative examples were placed in an air environment with a temperature of 25° C. and a humidity of 55% for 5 hours to test the oxidation level.

[0060] Table 1 Performance test results

[0061]

[0062] Data Analysis:

[0063] It can be seen from Examples 1-6 that the hydrogen storage material with a high hydrogen production rate prepared by the preparation method of the present invention can achieve rapid hydrogen absorption and desorption at 300°C, has a low kinetic barrier, and effectively solves the problem of easy passivation when exposed to air; it can be seen from Examples 2 and Examples 5-6 that the addition of anionic surfactants can further increase the hydrogen absorption and desorption rate and reduce the kinetic barrier.

[0064] It can be seen from Example 2 and Comparative Example 1 that the hydrothermal reaction of modified montmorillonite is crucial. The hydrothermal reaction can effectively form a uniform carbon layer on the surface of montmorillonite, improve its catalytic effect on magnesium hydride, and reduce the kinetic barrier. This is mainly due to the catalytic effect of the carbon layer and the adsorption of surface N elements.

[0065] It can be seen from Example 2 and Comparative Example 2 that directly mixing montmorillonite and magnesium hydride has a certain effect on improving the hydrogen absorption and desorption performance of magnesium hydride, but the effect is far inferior to the solution adopted by the present invention. This is mainly because 1,2,4-triaminoaniline dihydrochloride forms a carbon layer with a catalytic effect on the one hand, and on the other hand, montmorillonite is stripped into a lamellar structure. The lamellar structure effectively protects the magnesium hydride, reduces the generation of an inert oxide layer, and increases the contact area with the magnesium hydride. Another possible reason is that the lamellar structure can assist ball milling, so that the magnesium hydride has a higher specific surface area, thereby improving the hydrogen absorption and desorption efficiency.

[0066] It can be seen from Example 2 and Comparative Example 3 that, compared with directly ball-milling commercially available magnesium hydride, the hydrogen storage material prepared by the scheme of the present invention has a significantly improved hydrogen absorption and desorption rate and a reduced kinetic barrier.

[0067] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

Claims

1. A method for preparing a hydrogen storage material with a high hydrogen production rate, characterized in that: The method comprises the following steps: mixing magnesium hydride and carbon layer modified montmorillonite nanosheets in an organic solvent, and then vacuum drying and solid phase ball milling are performed in sequence to obtain a hydrogen storage material with a high hydrogen production rate; the weight ratio of the magnesium hydride, carbon layer modified montmorillonite nanosheets and organic solvent is 10:1-2:50-100; The preparation method of the carbon layer modified montmorillonite nanosheet is as follows: S1: Add 1,2,4-triaminoaniline dihydrochloride to a hydrochloric acid aqueous solution, dissolve it by ultrasonication, then add montmorillonite and deionized water, stir at 60-70°C for 3-4h, wash, and dry to obtain modified montmorillonite; S2: dispersing the modified montmorillonite in anhydrous ethanol, transferring to an autoclave, reacting at 180-200°C for 12-15h, washing, centrifuging, and drying to obtain carbon layer-modified montmorillonite nanosheets; An anionic surfactant is also added to the organic solvent; the amount of the anionic surfactant added is 3-5% of the weight of the magnesium hydride; The anionic surfactant is sodium dodecylbenzene sulfonate or sodium hexadecylbenzene sulfonate.

2. The method for preparing a hydrogen storage material with a high hydrogen production rate according to claim 1, characterized in that: The organic solvent is one of anhydrous toluene, cyclohexane and heptane.

3. The method for preparing a hydrogen storage material with a high hydrogen production rate according to claim 1, characterized in that: The ball-to-material ratio of the solid phase ball milling treatment is 30:1-2, the ball milling speed is 1000-1200r / min, and the ball milling time is 4-8h.

4. The method for preparing a hydrogen storage material with a high hydrogen production rate according to claim 1, characterized in that: In the step S1, the weight ratio of 1,2,4-triaminoaniline dihydrochloride, hydrochloric acid aqueous solution, montmorillonite and deionized water is 0.3-0.5:40-50:2-3:150-200.

5. The method for preparing a hydrogen storage material with a high hydrogen production rate according to claim 1, characterized in that: In the step S2, the weight ratio of the modified montmorillonite to anhydrous ethanol is 2-3:50-100.

6. A hydrogen storage material with a high hydrogen production rate, characterized in that: The method for preparing a hydrogen storage material with a high hydrogen production rate according to any one of claims 1 to 5 is obtained.

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