Metal organic framework material and preparation method thereof

Abstract

The invention provides a metal organic framework material and a preparation method thereof, the chemical formula of the metal organic framework material is MIL-101 (A)-Lix, A is one of Cr, Fe, Al and Mn, X is the molar ratio of MIL-101 (A) to Li, and the value of x is 35-55, the metal organic framework material is prepared by doping lithium salt into MIL-101 (A), and the result shows that the lithium salt is doped into MIL-101 (A), so that the metal organic framework material can be used for preparing a lithium ion battery, and the lithium ion battery can be used for preparing a lithium ion battery. The hydrogen storage performance of the material can be obviously improved under the condition that the specific surface area is not greatly changed.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of materials, in particular to a metal organic framework material and a preparation method. BACKGROUND

[0002] Hydrogen energy is a secondary energy source with abundant resources, green and low carbon, and wide application. Hydrogen energy can help renewable energy scale consumption, realize large-scale peak shaving and cross-season and cross-regional energy storage of power grids, and is an important direction of future energy transformation. Hydrogen energy has high energy density, and the combustion product is only water, without pollution, and is widely used in energy, transportation and industry. However, the storage and transportation problems of hydrogen energy limit its wide application. In order to realize the effective storage and transportation of hydrogen, safe, efficient and low-cost hydrogen storage materials are needed.

[0003] Metal organic framework (MOFs) is a typical porous crystalline material formed by orderly splicing organic linkers between metal nodes. The unique framework and pore channel structure characteristics of MOFs materials determine their unique advantages of high specific surface area, adjustable pore size and structure. MOFs hydrogen storage research has become a hot spot of solid-state hydrogen storage and has shown good application prospects. MIL-101(Cr) was first synthesized by Ferey et al. of France in 2005 by using hydrothermal reaction method, adding hydrofluoric acid at 220℃. Studies have found that the secondary structure unit of MIL-101(Cr) is formed by coordination of Cr3O ion clusters and terephthalic acid, and its structure is similar to the MTN zeolite topology structure, which has excellent chemical stability and high specific surface area, and is an ideal hydrogen storage material.

[0004] At present, improving the specific surface area of MIL-101(Cr) is one of the directions to improve the hydrogen storage performance, but the improvement of the specific surface area will reduce the stability of the material, so it is impossible to infinitely improve the specific surface area. Therefore, a modification method is needed which can not significantly change the specific surface area of the material but can improve the hydrogen storage performance. SUMMARY

[0005] The technical problem to be solved by the embodiments of the present application is to provide a metal organic framework material and a preparation method.

[0006] In order to solve the above technical problems, the present application provides a metal organic framework material, which has a chemical formula of MIL-101(A)-Lix, wherein A is one of Cr, Fe, Al and Mn, X is the molar ratio of MIL-101(A) to Li, and x is 35-55.

[0007] Preferably, x is 40-50, more preferably 42-48.

[0008] The present application also provides a method for preparing the metal organic framework material according to any one of the preceding embodiments, comprising reacting MIL-101(A) with a lithium salt in a volatile liquid to obtain MIL-101(A)-Lix.

[0009] Preferably, the reaction of MIL-101(A) with a lithium salt in a volatile liquid to obtain MIL-101(A)-Lix specifically comprises:

[0010] Providing a solution of a lithium salt;

[0011] Reacting MIL-101(A) in the solution of a lithium salt to obtain MIL-101(A)-Lix.

[0012] Preferably, the reaction time is greater than 12 hours.

[0013] Preferably, the method further comprises a step of drying the product after the reaction.

[0014] Preferably, the lithium salt is one or more of lithium perchlorate (LiClO4), lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium bis(oxalato)borate (LiBOB), lithium trifluoromethanesulfonimide (LiTFSI), and lithium bis(fluorosulfonyl)imide (LiFSI).

[0015] Preferably, the reaction of MIL-101(A) with a lithium salt in a volatile liquid to obtain MIL-101(A)-Lix specifically comprises:

[0016] Providing a mixture of MIL-101(A) and a volatile liquid;

[0017] Reacting the mixture with a lithium salt to obtain MIL-101(A)-Lix.

[0018] Preferably, the reaction time is greater than 12 hours.

[0019] The present application provides a metal organic framework material, MIL-101(A)-Lix, which is prepared by doping Li ions into MIL-101(A). Test results show that the present application can significantly improve the hydrogen storage performance of the material while keeping the specific surface area of the material unchanged by doping lithium ions into MIL-101(A). BRIEF DESCRIPTION OF DRAWINGS

[0020] To more clearly illustrate the technical solutions in the embodiments of this application 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 embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0021] Figures la-d The N2 adsorption-desorption curve (77K) test results of MIL-101(Cr)-Lix prepared in this invention;

[0022] Figures 2a-d The specific surface area of ​​MIL-101(Cr)-Lix prepared in this invention is calculated and fitted.

[0023] Figures 3a-d Pore ​​size distribution curve of MIL-101(Cr)-Lix prepared for this invention;

[0024] Figures 4a-d H2 adsorption-desorption curves of MIL-101(Cr)-Lix prepared for this invention at ambient pressure. Detailed Implementation

[0025] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0026] This invention provides a metal-organic framework material with the chemical formula MIL-101(A)-Lix, wherein A is one of Cr, Fe, Al, and Mn, and X is the molar ratio of MIL-101(A) to Li. The value of X is preferably 35-55, more preferably 40-50, more preferably 42-48, more preferably 43-47, and more preferably 44-46. By adjusting the appropriate doping amount, the adsorption capacity of hydrogen at normal pressure is increased by improving the heat of adsorption of hydrogen by the material. If the doping amount is too large, the heat of adsorption becomes high, leading to structural collapse and a significant reduction in specific surface area. If the doping amount is too small, although it will not cause a decrease in specific surface area, the modification performance will not be significant.

[0027] The present application also provides a method for preparing MIL-101(A)-Lix, in particular, MIL-101(A) is reacted with a lithium salt in a volatile liquid to obtain MIL-101(A)-Lix. The source of MIL-101(A) in the present application is not particularly limited, and can be prepared by a method well known to those skilled in the art, for example, using a metal crystal containing Cr, Al, Fe or Mn and an organic ligand by a hydrothermal reaction method, adding hydrofluoric acid. The specific preparation scheme is as follows: the metal crystal and the organic ligand are dissolved in water, 40% hydrofluoric acid is added during stirring, then ultrasonic treatment is performed, and then the reaction is carried out at 200-240°C, preferably 210-230°C in a reaction kettle, and the reaction time is preferably greater than 2 hours, more preferably greater than 4 hours, more preferably greater than 6 hours, and more preferably greater than 8 hours.

[0028] After the reaction is completed, cooling to room temperature is performed, and then washing with an organic solvent is performed, followed by drying. The drying is preferably performed using a vacuum oven, and the drying temperature is preferably 80-200°C, more preferably 90-180°C, more preferably 120-150°C, and the drying time is preferably greater than 8 hours, more preferably greater than 12 hours.

[0029] According to the present application, the organic washing solvent can be a ketone solvent such as methyl ethyl ketone (MEK), acetone, diethyl ketone, methyl isobutyl ketone (MIBK), methyl isopropyl ketone (MIPK), and cyclohexanone; an alcohol solvent such as methanol, ethanol, isopropyl alcohol, ethylene glycol, diethylene glycol (DEG), and glycerol; an ether solvent such as diethyl ether, diisopropyl ether, 1,2-dimethylethane (DME), 1,4-dioxane, tetrahydrofuran (THF), tetrahydropyran (THP), anisole, diethylene glycol dimethyl ether, and diethylene glycol ethyl ether; a cellosolve-based solvent such as methyl cellosolve, ethyl cellosolve, and phenyl cellosolve; an aliphatic hydrocarbon-based solvent such as hexane, pentane, heptane, and cyclohexane; an aromatic hydrocarbon-based solvent such as toluene, xylene, and benzene; an aromatic heterocyclic compound series such as pyridine, pyrazine, furan, pyrrole, and thiophene; an amide-based solvent such as N,N-dimethylformamide (DMF) and N,N-dimethylacetamide (DMA); a halogen compound-based solvent such as chlorobenzene, dichloromethane, chloroform, and 1,2-dichloroethane; an ester-based solvent such as ethyl acetate, methyl acetate, and ethyl formate; a sulfur compound-based solvent such as dimethyl sulfoxide (DMSO) and sulfolane; and a nitro-based solvent such as acetonitrile, propionitrile, and acrylonitrile. One or more of the above washing solvents can be selected and used for alternate washing or mixed washing.

[0030] According to the present application, the Cr, Al, Fe, Mn metal crystal can be preferably FeCl3·6H2O, CrCl3·6H2O, AlCl3·6H2O, Fe(NO3)3·9H2O, Cr(NO3)3·9H2O, Al(NO3)3·9H2O, Mn(NO3)2·9H2O, etc., but is not limited thereto. The specific examples of the organic ligand can be terephthalic acid, 2-amino-1,4-benzenedicarboxylic acid, 2-hydroxy-1,4-benzenedicarboxylic acid, but are not limited thereto.

[0031] According to the present application, the lithium salt can be an inorganic salt or an organic salt, examples of the inorganic salt can be one or more of lithium nitrate, lithium chloride, lithium acetate, lithium sulfate, or lithium carbonate, examples of the organic salt can be one or more of lithium acetate, tetrabutyl lithium bromide, lithium pyridine acetate, methyllithium, lithium ethoxide, lithium perchlorate (LiClO4), lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium bisoxalate borate (LiBOB), lithium trifluoromethylsulfonylimide (LiTFSI), lithium bisfluorosulfonylimide (LiFSI), preferably lithium trifluoromethylsulfonylimide or lithium bisfluorosulfonylimide (LiFSI).

[0032] According to the present application, the volatile liquid refers to any liquid that can dissolve the lithium salt, preferably water, aqueous liquid, carbonate-containing liquid, or a mixture thereof, the carbonate-containing liquid can be ethylene carbonate, propylene carbonate, etc., but is not limited thereto, and the preferred volatile liquid is water. There is no particular limitation on the concentration of the lithium salt, and any concentration below the maximum solubility of the lithium salt can achieve the purpose of the present application. According to the present application, an aqueous lithium salt solution is preferably used, wherein the lithium salt concentration is preferably 0.01 mol / L to 0.09 mol / L, more preferably 0.02 mol / L to 0.08 mol / L, and more preferably 0.02 mol / L to 0.06 mol / L.

[0033] According to the present application, when the MIL-101(A) is reacted with the lithium salt in the volatile liquid, it specifically includes providing a lithium salt solution, and then immersing the MIL-101(A) in the lithium salt solution to obtain MIL-101(A)-Lix, the immersion reaction time is preferably greater than 12 hours, more preferably greater than 18 hours, and more preferably greater than 24 hours, the longer the immersion time, the more complete the reaction.

[0034] According to the present application, when the MIL-101(A) is reacted with the lithium salt in the volatile liquid, a mixture of the MIL-101(A) and the volatile liquid can also be provided, and the lithium salt is incorporated into the mixture to obtain the MIL-101(A)-Lix. The reaction time is preferably greater than 12 hours, more preferably greater than 18 hours, and more preferably greater than 24 hours. The longer the soaking time, the more complete the reaction.

[0035] According to the present application, after the reaction is completed, the volatile liquid is preferably removed using a drying method. The drying temperature is preferably 20-100°C, more preferably 20-50°C, and more preferably 20-35°C, but is not limited thereto. The drying is preferably performed in a vacuum drying oven.

[0036] The effects of the present application are illustrated below with specific examples.

[0037] Example 1: Preparation of MIL-101(Cr)

[0038] 8.0 g of Cr(NO3)3·9H2O and 3.36 g of terephthalic acid were weighed and dissolved in 80 ml of deionized water while stirring. During the stirring, 2 ml of 40% hydrofluoric acid was added. After 30 minutes of ultrasonic treatment, the mixture was transferred to a reaction kettle and placed at 220°C for 8 hours. After the product was cooled to room temperature, it was washed three times by centrifugation using N,N-dimethylformamide (DMF) and anhydrous ethanol alternately, and finally dried in an oven at 130°C for 12 hours to obtain a green powder product, which was MIL-101(Cr).

[0039] Example 2: Preparation of MIL-101(Cr)-Lix

[0040] Preparation of lithium salt solution: Lithium salt (lithium trifluoromethanesulfonimide, LiTFSI) was added to water to prepare lithium salt solutions with concentrations of 0.06 mol / L, 0.03 mol / L, and 0.01 mol / L, respectively;

[0041] The above-prepared lithium salt solutions were added to the MIL-101(Cr) prepared in Example 1, and the molar ratios of MIL-101(Cr) to lithium salt solutions were 25:1, 45:1, and 100:1, respectively. After soaking for 24 hours, the samples were dried in a vacuum drying oven at 25°C for 24 hours to obtain MIL-101(Cr)-Li 25 , MIL-101(Cr)-Li 45 , and MIL-101(Cr)-Li 100 .

[0042] To calculate the specific surface area, the specific surface areas of MIL-101(Cr), MIL-101(Cr)-Li 25MIL-101(Cr)-Li 45 MIL-101(Cr)-Li 100 The N2 adsorption-desorption curve (77K) is shown in the test results. Figures la-d As shown, where Figure la The corresponding MIL-101(Cr) results Figure lb Corresponding to MIL-101(Cr)-Li 25 As a result, Figure lc Corresponding to MIL-101(Cr)-Li 45 As a result, Figure Id Corresponding to MIL-101(Cr)-Li 100 The result.

[0043] according to Figures la-d MIL-101(Cr) and MIL-101(Cr)-Li 25 MIL-101(Cr)-Li 45 MIL-101(Cr)-Li 100 The calculated specific surface area is as follows Figures 2a-d As shown, where Figure 2a The corresponding calculation results for MIL-101(Cr) Figure 2b Corresponding to MIL-101(Cr)-Li 25 The calculation results Figure 2c Corresponding to MIL-101(Cr)-Li 45 The calculation results Figure 2d Corresponding to MIL-101(Cr)-Li 100 The calculation results Figures 2a-d Calculations show that the specific surface area decreases after doping because lithium salts cause excessively high adsorption heat, leading to structural collapse, especially when the doping ratio reaches 25:1. Figure 2b When the surface area decreases most significantly, the specific surface area decreases most noticeably.

[0044] Measurement of MIL-101(Cr) and MIL-101(Cr)-Li 25 MIL-101(Cr)-Li 45 MIL-101(Cr)-Li 100 The aperture distribution curves are shown in the figure. Figures 3a-d As shown, where Figure 3a The corresponding MIL-101(Cr) test results Figure 3b Corresponding to MIL-101(Cr)-Li 25 The test results Figure 3c Corresponding to MIL-101(Cr)-Li 45 The test results Figure 3dMIL-101(Cr)-Li 100 The test results of MIL-101(Cr)-Li Figures 3a-d The test results of MIL-101(Cr)-Li

[0045] The test results of MIL-101(Cr), MIL-101(Cr)-Li 25 MIL-101(Cr)-Li 45 MIL-101(Cr)-Li 100 The H2 adsorption / desorption curves (77K) of MIL-101(Cr), MIL-101(Cr)-Li Figures 4a-d The test results of MIL-101(Cr)-Li Figure 4a The test results of MIL-101(Cr)-Li Figure 4b The test results of MIL-101(Cr)-Li 25 The test results of MIL-101(Cr)-Li Figure 4c The test results of MIL-101(Cr)-Li 45 The test results of MIL-101(Cr)-Li Figure 4d The test results of MIL-101(Cr)-Li 100 The test results of MIL-101(Cr)-Li Figures 4a-d The test results of MIL-101(Cr)-Li 45 The test results of MIL-101(Cr)-Li Figure 4a The test results of MIL-101(Cr)-Li 3 The test results of MIL-101(Cr)-Li 3 The test results of MIL-101(Cr)-Li Figure 4b The test results of MIL-101(Cr)-Li Figure 4d The test results of MIL-101(Cr)-Li

[0046] Although the present application discloses the above, the present application is not limited to this. Any person skilled in the art, without departing from the spirit and scope of the present application, can make various changes and modifications, therefore the protection scope of the present application should be limited by the scope defined in the claims.

Claims

1. A metal organic framework material, characterized in that, A is one of Cr, Fe, Al, Mn, and x is a value between 35 and 55.

2. The metal organic framework material of claim 1, wherein, x is a value between 40 and 50.

3. The metal organic framework material of claim 2, wherein, x is a value between 42 and 48.

4. A method of preparing the metal organic framework material of any one of claims 1 to 3, characterized in that, The MIL-101(A)-Lix is obtained by reacting MIL-101(A) with a lithium salt in a volatile liquid.

5. The method of claim 4, wherein, The method for preparing MIL-101(A)-Lix comprises the following steps: providing a solution of a lithium salt; reacting MIL-101(A) in the solution of the lithium salt to obtain MIL-101(A)-Lix.

6. The method of claim 5, wherein, The reaction time is greater than 12 hours.

7. The method of claim 6, wherein, The method further comprises a step of drying the product after the reaction.

8. The method of claim 5, wherein, The lithium salt is one or more of lithium perchlorate (LiClO4), lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium bis(oxalato)borate (LiBOB), lithium trifluoromethanesulfonimide (LiTFSI), and lithium bis(fluorosulfonyl)imide (LiFSI).

9. The method of claim 4, wherein, The method for preparing MIL-101(A)-Lix comprises the following steps: providing a mixture of MIL-101(A) and a volatile liquid; adding a lithium salt to the mixture to obtain MIL-101(A)-Lix.

10. The method of claim 9, wherein, The reaction time is greater than 12 hours.

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