A transition metal-based high specific surface area metal organic framework material, a preparation method thereof and application thereof in methane storage

Abstract

The application belongs to the technical field of gas storage, and particularly relates to a novel transition metal-based high specific surface area metal organic framework material for methane storage, and a preparation method and application thereof. The transition metal-based high specific surface area metal organic framework material has bidentate or multidentate organic compound ligands as organic ligands, transition metal ions as metal centers, and is assembled into one-dimensional metal-tooth chains through a solvothermal method, and adjacent one-dimensional metal-tooth chains are bridged in parallel through ligands to form a high specific surface area framework. The transition metal ions are connected with the bidentate or multidentate organic compound ligands through coordination bonds. The transition metal-based high specific surface area metal organic framework material has a porous structure. The material obtained by the application has excellent methane storage performance at 273 K and 298 K, and the material has the advantages of high stability and strong regeneration capacity.

Description

Technical Field

[0001] This invention relates to the field of gas storage materials technology, and in particular to a transition metal-based high specific surface area metal-organic framework material, its preparation method, and its application in methane storage. Background Technology

[0002] With the continuous rise in atmospheric carbon dioxide concentration, the development of clean alternative fuels to replace traditional petroleum-based fuels has become an urgent need in the global energy sector. Methane, as a highly promising alternative fuel for transportation, is considered an important transitional fuel due to its lower carbon dioxide emissions compared to gasoline. However, current methane storage and transportation for vehicles rely on liquefied natural gas (LNG) and compressed natural gas (CNG) technologies, which suffer from high costs and significant safety risks, severely hindering their large-scale application. To promote the development of methane storage technology, the U.S. Department of Energy (DOE) has set stringent requirements: a material volumetric gas storage capacity of 350 cm³ at room temperature and 35–100 bar. 3 (STP) / cm 3 The gas storage capacity by mass must reach 0.5 g / g; considering the actual changes in filling density, the gas cylinder volumetric storage capacity must meet 263 cm³. 3 (STP) / cm 3 Developing novel high-performance adsorption materials is the core path to achieving the above goals. Among them, metal-organic frameworks (MOFs) have become a research hotspot in the field of methane storage due to their tunable pore chemistry, controllable pore structure morphology, and high design flexibility.

[0003] Existing MOF materials face a key bottleneck in optimizing methane storage performance: an inherent contradiction exists between pore structure and packing density. While pore structure engineering through ligand extension can improve mass adsorption capacity, it easily induces framework interpenetration, reducing overall pore volume; simultaneously, increased pore volume often leads to decreased framework density, impairing volumetric adsorption capacity. In practical applications such as automotive applications, volumetric gas storage capacity is far more important than mass gas storage capacity due to the limited volume of the gas storage cylinder. This contradiction becomes a core obstacle to the practical application of MOF materials. Therefore, developing a MOF material that combines excellent pore structure, high packing density, and strong stability, while overcoming the aforementioned contradiction, is crucial for achieving efficient methane storage. Summary of the Invention

[0004] To address the technical problems of existing MOF materials in methane storage, such as imbalance between pore structure and packing density, insufficient volumetric gas storage capacity, and poor stability, this invention provides a transition metal-based high specific surface area metal-organic framework material, its preparation method, and its application in methane storage. This invention provides a transition metal-based high specific surface area MOF material that achieves an optimal balance between porosity and packing density, possessing ultra-high volumetric methane storage capacity, excellent structural stability and cycling performance, meeting stringent DOE requirements, and suitable for practical methane storage scenarios such as vehicle-mounted applications. The composition and size of the transition metal-based high specific surface area MOF material can be adjusted and controlled by the reaction temperature, reaction time, and the proportion of metal ions added. The preparation process of this invention utilizes a simple and controllable solvothermal self-assembly method to rapidly synthesize stable porous metal-organic framework materials, the composition of which can be controlled by the types and concentration ratios of the added transition metal ions and organic ligands.

[0005] The first objective of this invention is to provide a transition metal-based high specific surface area metal-organic framework material, wherein the transition metal-based high specific surface area metal-organic framework material uses bidentate or multidentate organic compound ligands as organic ligands and transition metal ions as metal centers, and is assembled into one-dimensional metal-dentate chains by a solvothermal method, and adjacent one-dimensional metal-dentate chains are connected by parallel ligand bridging to form a high specific surface area framework; the high specific surface area framework contains interacting CH···N, CH···O, CH···S or CH···P and CH···π, which enhance the structural stability and adsorption selectivity of the material through interaction;

[0006] The transition metal ions are connected to bidentate or polydentate organic compound ligands via coordination bonds.

[0007] The transition metal-based high specific surface area metal-organic framework material has a porous structure.

[0008] In some embodiments of the present invention, the specific surface area of ​​the transition metal-based high specific surface area metal-organic framework material is 1000–3000 m². 2 / g, with a pore size distribution of 0.5–2.0 nm.

[0009] In some embodiments of the present invention, the transition metal ion is selected from one or more of cobalt ions, copper ions, zinc ions, and nickel ions.

[0010] In some embodiments of the present invention, the bidentate or multidentate organic ligand is a rigid ligand containing at least one heteroatom with a lone pair of electrons from oxygen, nitrogen, sulfur, and phosphorus.

[0011] In some embodiments of the present invention, the heteroatom includes one or more of carboxyl, pyridyl, porphyrinyl, pyrimidinyl, phosphate, sulfonic acid, amino, nitrile, mercapto, and heterocyclic groups.

[0012] In some embodiments of the present invention, the bidentate or multidentate organic compound ligands include 1,4-bis(1H-pyrazol-4-yl)benzene (CAS No.: 1036248-62-0) and / or 4,4'-bis(1H-pyrazol-4-yl)biphenyl (CAS No.: 1230878-51-9).

[0013] In some embodiments of the present invention, the molar ratio of the transition metal ion to the organic compound ligand is (1:1) to (1:4).

[0014] A second objective of this invention is to provide a method for preparing the aforementioned transition metal-based high specific surface area metal-organic framework material, comprising the following steps:

[0015] The transition metal salt and organic ligand were mixed and dissolved in an aqueous mixed solvent, followed by a hydrothermal heating reaction.

[0016] After solid-liquid separation, the solid phase is collected and washed with a high-boiling-point polar aprotic solvent. The obtained solid phase is then replaced with a low-boiling-point polar aprotic solvent to replace the residual high-boiling-point solvent and impurities in the pores. Subsequently, it is vacuum dried to obtain the transition metal-based high specific surface area metal-organic framework material.

[0017] In some embodiments of the present invention, the high-boiling-point polar aprotic solvent is selected from one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N,N-diethylformamide, and N-methylpyrrolidone; the low-boiling-point polar aprotic solvent is selected from one or more of acetone, methanol, ethanol, dichloromethane, and 1,4-dioxane.

[0018] In some embodiments of the present invention, the temperature of the hydrothermal heating reaction is 80~250°C, and the time of the hydrothermal heating reaction is 1 day~5 days;

[0019] The mixed solvent includes DMF and water, with a volume ratio of DMF to water of (25:1) to (250:1).

[0020] The solvent replacement time is 24~120 h;

[0021] The vacuum drying temperature is 80~150℃, and the time is 12~48 h.

[0022] A third objective of this invention is to provide the application of the aforementioned transition metal-based high specific surface area metal-organic framework material in methane storage.

[0023] In some embodiments of the present invention, the methane is stored at a pressure of 35 to 100 bar and at a temperature of 273 K to 298 K.

[0024] The technical solution of the present invention has the following advantages compared with the prior art:

[0025] This invention utilizes a solvothermal method to synthesize cobalt-based metal-organic frameworks with bidentate or multidentate organic compound ligands as organic ligands and transition metal ions as metal centers, assembling them to form a high specific surface area metal-organic framework. Based on the strong metal-nitrogen bond formed between the bidentate or multidentate organic compound ligands and the transition ions, the framework exhibits high thermal stability and maintains structural integrity in various solvents and air environments, making it suitable for long-term, repeated use. The preparation conditions are simple and the process is straightforward.

[0026] The cobalt-based high specific surface area metal-organic framework material obtained in this invention has a highly stable framework provided by rigid ligands and strong metal-nitrogen bonds, which ensures gas storage performance under high pressure / cycle conditions. The one-dimensional square large pore size realizes high adsorption capacity and fast kinetics of methane molecules. The non-polar pore environment is adapted to the molecular characteristics of methane and avoids competitive adsorption under actual working conditions. The convenient synthesis and modification make it both valuable for basic research and has potential for practical application.

[0027] The cobalt-based high specific surface area metal-organic framework material obtained in this invention possesses both high specific surface area and porosity. Abundant modifiable sites allow for precise control of gas storage performance, and the transition metal alloy is inexpensive. Combining these advantages, this material can serve as a highly efficient adsorbent for applications in the gas field.

[0028] This invention successfully prepared cobalt-based high specific surface area metal-organic framework materials by regulating ligand configuration and optimizing reaction parameters, achieving an unprecedented balance between porosity and packing density, and its methane volume storage performance has comprehensively broken through the DOE index.

[0029] The cobalt-based high specific surface area metal-organic framework material obtained in this invention relies mainly on the CH···N, CH···O, CH···S, CH···P and CH···π interactions provided by bidentate or multidentate organic compound ligands to ensure strong interaction between methane and the framework in the absence of open metal sites, thereby achieving high-capacity adsorption. Attached Figure Description

[0030] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein...

[0031] Figure 1 This is a schematic diagram of the synthesis of Co(pbp) crystal material in a DMF-H2O mixed solution according to the present invention.

[0032] Figure 2 The X-ray diffraction (XRD) patterns of the Co(pbp) crystal material synthesized, solvent exchanged, and activated according to the present invention are shown.

[0033] Figure 3 This is a scanning electron microscope (SEM) image of the Co(pbp) crystal material in this invention.

[0034] Figure 4 The thermogravimetric analysis (TGA) curve of the Co(pbp) crystal material in this invention is shown.

[0035] Figure 5 This is the N2 adsorption-desorption isotherm of the Co(pbp) crystal material in this invention.

[0036] Figure 6 The X-ray diffraction (XRD) patterns of the Co(pbp) crystal material in this invention under different solvent and air environments are shown.

[0037] Figure 7 This is a schematic diagram showing the total methane adsorption capacity of the Co(pbp) crystal material described in this invention under pressure conditions of 273 K, 283 K, 298 K, and 80 bar; wherein, (a) is expressed in volume units cm 3 / g represents the total methane adsorption amount; (b) is expressed in volume units cm. 3 / cm 3 (c) is a graph comparing the methane storage performance of the Co(pbp) crystal material obtained in this invention and most high-performance adsorbents at near-freezing temperatures (273 K or 270 K); (d) is a graph comparing the total volumetric methane adsorption capacity and working capacity of the Co(pbp) crystal material obtained in this invention and most high-performance adsorbents at room temperature (298 K or 296 K) based on apparent density / crystal density.

[0038] Figure 8 This is a schematic diagram of the packing density of the Co(pbp) crystal material and the DFT-simulated methane adsorption sites in this invention; where (a) is the packing density and (bg) is a schematic diagram of the DFT-simulated methane adsorption sites.

[0039] Figure 9 This represents the total methane adsorption amount of the Co(pbp) crystal material in this invention per cycle.

[0040] Figure 10 The image shows the PXRD pattern of the Co(pbp) crystal material after five cycles in this invention.

[0041] Figure 11 This is the BET plot of the Co(pbp) crystal material after five cycles in this invention. Detailed Implementation

[0042] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0043] Example 1:

[0044] This embodiment provides a method for preparing a Co(pbp) crystal material, as detailed below:

[0045] Cobalt nitrate hexahydrate (0.3 mmol) and 4,4'-bis(1H-pyrazol-4-yl)biphenyl (0.3 mmol) were placed in a 50 mL glass sample vial, and dissolved in a mixed solvent of 25 mL N,N-dimethylformamide and 100 μL water. The mixture was then heated at 150 °C for 3 days. After cooling the reaction system to room temperature, the purple crystalline product was collected by filtration and washed with fresh DMF (10 mL × 3 times) to obtain freshly synthesized Co(pbp). The obtained solid was solvent-exchanged with 10 mL methanol for 72 h to obtain methanol-exchanged Co(pbp). The methanol-exchanged solid product was then placed under dynamic vacuum at 150 °C for 24 h to complete the activation of the product, yielding Co(pbp) crystalline material (activated Co(pbp)).

[0046] Structural characterization:

[0047] The Co(pbp) crystal material obtained in Example 1 was subjected to powder X-ray diffraction (PXRD) testing. The results were consistent with the simulated pattern, indicating that the product has a high-purity crystal structure (see results). Figure 2 Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) mapping confirmed that C, N, and Co elements were uniformly distributed within the framework and that the material exhibited a regular dodecahedral morphology (characterization results are shown in [link to documentation]). Figure 3 Thermogravimetric analysis (TGA) results are shown below. Figure 4 The figure shows that the Co(pbp) crystal material maintains its structural integrity below 400℃ and has excellent thermal stability.

[0048] Performance testing

[0049] (1) Pore performance testing

[0050] The N2 adsorption-desorption isotherm of the Co(pbp) crystal material obtained in Example 1 was tested at 77 K, and the results are shown in [Figure 1]. Figure 5 The results showed that the isotherm was a typical type I isotherm, indicating that the Co(pbp) crystal material has a microporous structure; the BET specific surface area was 2437 m². 2 / g, the pore size calculated by NLDFT method is concentrated at around 15.7 Å, consistent with the structural characterization results; the packing density test results are shown in […]. Figure 8 The figure shows that the maximum bulk density of the Co(pbp) crystal material after being compacted with a syringe is 1.19 g / cm³. 3 The specific surface area is 2900 m². 2 / cm 3 .

[0051] (2) Stability test

[0052] The stability of the Co(pbp) crystal material obtained in Example 1 was determined by immersing it in different organic solvents for one week and exposing it to air for one year. The specific test methods are as follows:

[0053] 50 mg of activated Co(pbp) crystal material was immersed in 20 mL of different organic solvents for one week. After immersion, X-ray diffraction (XRD) was performed on the crystal material. Simultaneously, another 50 mg of activated Co(pbp) crystal material was exposed to air for one year. After exposure, X-ray diffraction (XRD) was performed on the Co(pbp) crystal material to characterize its crystal structure stability. The test results are shown below. Figure 6 As shown in the figure, its XRD pattern is completely consistent with the simulated pattern, indicating that the Co(pbp) crystal material has excellent structural stability.

[0054] (3) Methane storage performance test

[0055] The high-pressure methane storage performance of the Co(pbp) crystal material obtained in Example 1 was tested using the following specific test method:

[0056] Before testing, the blank sample cell was weighed and its initial weight recorded. Then, the Co(pbp) crystal material was loaded into the sample cell and pre-treated with activation (vacuum activation at 150℃ for 2 hours). After activation, the sample cell containing the pre-treated sample was weighed again to determine the actual loading amount. Subsequently, methane adsorption was measured using a volumetric method. During the measurement, the volume of the measurement system was accurately measured first to provide a basis for calculating the adsorption volume. Then, based on the gas law and the gas pressure change within the measurement system, the adsorption volume of the sample was calculated. The dead volume of the sample cell was determined using 99.9999% pure helium to ensure the accuracy of the measurement data. An automated volumetric adsorption analyzer was used to determine the high-pressure methane excess adsorption isotherm of the sample within the pressure range of 0–80 bar. The measurement temperature was precisely controlled by a computer-controlled ethylene glycol-water bath. After the test, the adsorption data was corrected by subtracting the background adsorption value measured in the blank sample cell under the same test parameters, ultimately obtaining the mass excess adsorption isotherm n of the Co(pbp) crystal material. ex (P, T). Total adsorption amount n tot (P, T) reflects the true gas storage performance of porous materials, but cannot be directly measured. It is calculated using the following formula: Experimental results are shown in [link to experimental results]. Figure 7 .

[0057] n tot (P, T) = n ex (P, T) + ρ gas (P, T) ×V p ,

[0058] Where, ρ gas (P, T) represents the density of bulk methane at pressure P and temperature T, V p This represents the pore volume of the Co(pbp) crystal material measured by the nitrogen adsorption isotherm at 77 K. The volume adsorption isotherm is obtained by multiplying the mass adsorption isotherm by the crystal density of the main framework of the Co(pbp) crystal material.

[0059] As shown in the figure, the methane adsorption-desorption isotherms of the Co(pbp) crystal material obtained in Example 1 within the pressure range of 0-80 bar are as follows: at 273 K and 80 bar, the total adsorption capacity is 356 cm⁻¹. 3 (STP) / cm 3 The desorption capacity is 270 cm³ at 5-80 bar. 3 (STP) / cm 3 DOE 350 cm 3 (STP) / cm 3 Volumetric properties: At 298 K and 80 bar, the total adsorption capacity is 321 cm⁻¹.3 (STP) / cm 3 The desorption capacity is 252 cm³ at 5-80 bar. 3 (STP) / cm 3 263 cm longer than DOE 3 (STP) / cm 3 It exhibits performance comparable to gas storage cylinders and is superior to all previously reported MOF-based methane adsorbents.

[0060] (4) Cyclic stability test

[0061] The Co(pbp) crystal material obtained in Example 1 was subjected to five methane adsorption-desorption cycles within a pressure range of 0–80 bar. After each cycle, it underwent 30 minutes of vacuum regeneration. The results are shown in […]. Figure 9 As shown in the figure, after the cycle, the total methane adsorption capacity of the material decreased by only 1.2%, and the PXRD pattern was consistent with the initial pattern (e.g., ...). Figure 10 As shown), the BET specific surface area decreased slightly but there was no significant pore structure collapse, indicating that the material has excellent cycle stability (e.g., Figure 11 (As shown).

[0062] Sources of MOF-based methane adsorbents have been reported:

[0063] 1. HCP-DPP: “High-Capacity Volumetric Methane Storage in Hyper-Cross-Linked Porous Polymers via Flexibility Engineering of Building Units” Advanced Materials 2025, 37, 2418005.

[0064] 2. HCP-SBF / HCP-TPM: “Porosity Engineering of Hyper-Cross-LinkedPolymers Based on Fine-Tuned Rigidity in Building Blocks and High-PressureMethane Storage Applications” Macromolecules 2023, 56, 1213-1222.

[0065] 3、COF-320: “Single-Crystal Structure of a Covalent Organic Framework”Journal of the American Chemical Society, 2013, 135, 16336-16339.

[0066] 4、COF-102: “Storage of Hydrogen, Methane, and Carbon Dioxide inHighly Porous Covalent Organic Frameworks for Clean Energy Applications”Journal of the American Chemical Society, 2009, 131, 8875-8883.

[0067] 5、HOF-RPH200: “Double-Walled Mesoporous Hydrogen-Bonded OrganicFrameworks with High Methane Storage Capacity” J. Am. Chem. Soc. 2025, 147,16412-16419.

[0068] 6、ST-2: “Engineering of Pore Geometry for Ultrahigh Capacity MethaneStorage in Mesoporous Metal-Organic Frameworks” Journal of the AmericanChemical Society, 2017, 139, 13300-13303.

[0069] 7、PCN-46a / ZJU-105a: “Tailoring the Pore Geometry and Chemistry inMicroporous Metal-Organic Frameworks for High Methane Storage WorkingCapacity” Chemical Communications, 2019, 55, 11402-11405.

[0070] 8、Ni-MOF-74 / HKUST-1: “Methane Storage in Metal-Organic Frameworks:Current Records, Surprise Findings, and Challenges” J. Am. Chem. Soc. 2013,135, 11887-11894.

[0071] 9、MOF-519: “High Methane Storage Capacity in Aluminum Metal-OrganicFrameworks” J. Am. Chem. Soc. 2014, 136, 5271-5274.

[0072] 10、MOF-905: “High Methane Storage Working Capacity in Metal-OrganicFrameworks with Acrylate Links” J. Am. Chem. Soc. 2016, 138, 10244-10251.

[0073] 11、Al-soc-MOF-1: “MOF Crystal Chemistry Paving the Way to Gas StorageNeeds: Aluminum-Based soc-MOF for CH4, O2, and CO2 Storage” J. Am. Chem. Soc.2015, 137, 13308-13318.

[0074] 12、MOF-210: “Ultrahigh Porosity in Metal-Organic Frameworks” Science2010, 329, 424-428.

[0075] 13、Co(bdp): “Methane storage in flexible metal-organic frameworkswith intrinsic thermal management” Nature 2015, 527, 357-361.

[0076] 14、NU-1500-Al: “Balancing volumetric and gravimetric uptake in highlyporous materials for clean energy” Science 2020, 368, 297-303.

[0077] 15、Fe-ncb-BTDDC-II / Fe-ncb-TPDC-II: “High-Connected Ternary Metal-Organic Framework Platform: Synthesis, Structure, and Methane StorageCapacity” J. Am. Chem. Soc. 2025, 147, 21811-21817.

[0078] 16、MFU-4l-Li: “Fine-Tuning a Robust Metal-Organic Framework towardEnhanced Clean Energy Gas Storage” J. Am. Chem. Soc. 2021, 143, 18838-18843.

[0079] 17、SHCP-3-Br: “Dibromomethane Knitted Highly Porous Hyper-Cross-Linked Polymers for Efficient High-Pressure Methane Storage” AdvancedMaterials 2024, 36, 2307579.

[0080] 18、3D-TFB-COF-Et: “Ultrahigh-surface Area Covalent Organic Frameworksfor Methane Adsorption” Science 2024, 386, 693-696.

[0081] 19、COF-150: “High-capacity methane storage in flexible alkane-linkedporous aromatic network polymers” Nat Energy 2019, 4, 604-611.

[0082] 20. ZJU-HOF-5a: “Construction of Highly Porous and Robust Hydrogen-Bonded Organic Framework for High-Capacity Clean Energy Gas Storage” Angewandte Chemie International Edition, 2024, 63, e202411753.

[0083] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A transition metal-based high specific surface area metal-organic framework material, characterized in that, The transition metal-based high specific surface area metal-organic framework material uses bidentate or multidentate organic compound ligands as organic ligands and transition metal ions as metal centers. It is assembled into one-dimensional metal-dentate chains by a solvothermal method. Adjacent one-dimensional metal-dentate chains are connected by parallel ligand bridging to form a high specific surface area framework. There are interacting CH···N and CH···π in the high specific surface area framework, which enhance the structural stability and adsorption selectivity of the material through interaction. The transition metal ions are connected to bidentate or polydentate organic compound ligands via coordination bonds. The transition metal-based high specific surface area metal-organic framework material has a porous structure; The transition metal ion is selected from cobalt ions; The bidentate or multidentate organic compound ligand is 4,4'-bis(1H-pyrazol-4-yl)biphenyl.

2. The transition metal-based high specific surface area metal-organic framework material according to claim 1, characterized in that, The specific surface area of ​​the transition metal-based high specific surface area metal-organic framework materials is 1000–3000 m². 2 / g, with a pore size distribution of 0.5–2.0 nm.

3. The transition metal-based high specific surface area metal-organic framework material according to claim 1, characterized in that, The molar ratio of the transition metal ion to the organic ligand is (1:1) to (1:4).

4. A method for preparing a transition metal-based high specific surface area metal-organic framework material as described in any one of claims 1 to 3, characterized in that, Includes the following steps: The transition metal salt and organic ligand were mixed and dissolved in an aqueous mixed solvent, followed by a hydrothermal heating reaction. After solid-liquid separation, the solid phase is collected and washed with a high-boiling-point polar aprotic solvent. The obtained solid phase is then replaced with a low-boiling-point solvent to displace the residual high-boiling-point solvent in the pores, followed by vacuum drying to obtain the transition metal-based high specific surface area metal-organic framework material. The high-boiling-point polar aprotic solvent is selected from one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N,N-diethylformamide, and N-methylpyrrolidone. The low-boiling-point solvent is selected from one or more of acetone, methanol, ethanol, dichloromethane, and 1,4-dioxane.

5. The preparation method according to claim 4, characterized in that, The hydrothermal heating reaction temperature is 80~250℃, and the hydrothermal heating reaction time is 1 day~5 days; The solvent replacement time is 24~120 h; The vacuum drying temperature is 80~150℃, and the time is 12~48 h.

6. The application of the transition metal-based high specific surface area metal-organic framework material according to any one of claims 1 to 3 in methane storage.

7. The application according to claim 6, characterized in that, The methane is stored at a pressure of 35-100 bar and a temperature of 273 K-298 K.

Images