A multi-level porous material and its preparation method and application

Abstract

The present invention belongs to the field of carbon material technology, and specifically relates to a multi-level porous material, its preparation method, and application. The present invention provides a method for preparing a multi-level porous material, comprising the following steps: firstly mixing an ethylene polymer, a soluble metal salt, a fluorine-containing compound, and a polar organic solvent, followed by freeze-drying to obtain a matrix material; and secondly mixing the matrix material with a nitrogen-containing compound, followed by calcination and acid leaching to obtain the multi-level porous material. The multi-level porous material obtained by the preparation method of the present invention has a strong structure, improved stability, and is less prone to structural collapse during application.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon materials, and in particular relates to a multi-level porous material and a preparation method and application thereof. Background Art

[0002] Hierarchical porous materials can be divided into three categories based on pore diameter: macroporous materials with pore diameters greater than 50 nm, mesoporous materials with pore diameters between 2 and 50 nm, and microporous materials with pore diameters less than 2 nm. Hierarchical porous materials offer advantages such as good permeability, a well-developed pore structure, and large specific surface area and pore volume. They transcend the limitations of traditional single-stage porous materials, which typically have a single pore structure. They are widely used in various technical fields, including adsorption and filtration materials, catalyst carriers, and drug carriers.

[0003] Publication No. CN101172243A discloses a microporous / mesoporous composite material, but the obtained multi-level porous material has poor strength and the multi-level porous structure is prone to collapse during use. Summary of the Invention

[0004] The purpose of the present invention is to provide a multi-level porous material and its preparation method and application. The multi-level porous material prepared by the preparation method provided by the present invention has a strong structure and high stability, and is not prone to structural collapse during application.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention provides a method for preparing a multi-level porous material, comprising the following steps:

[0007] The ethylene polymer, the soluble metal salt, the fluorine-containing compound and the polar organic solvent are mixed in one stage, and freeze-dried to obtain a matrix material;

[0008] The matrix material and the nitrogen-containing compound are mixed in two stages, and then calcined and acid-leached in sequence to obtain the hierarchical porous material.

[0009] Preferably, the ethylene polymer includes one or more of ethylene-vinyl acetate copolymer, polyethylene and polyvinyl pyrrolidone;

[0010] The fluorine-containing compound includes one or more of polytetrafluoroethylene, calcium fluoride, hydrofluoric acid, sodium fluoride, uranium hexafluoride, sodium fluorosilicate and boron trifluoride.

[0011] Preferably, the mass ratio of the ethylene polymer, the soluble metal salt and the fluorine-containing compound is 1:(0.05-0.5):(0.5-1.5).

[0012] Preferably, the freeze-drying temperature is -20 to -5°C.

[0013] Preferably, the nitrogen-containing compound includes one or more of p-nitroaniline, benzidine, ethyleneimine, nitrosoamines, nitrosoamides and melamine;

[0014] The mass ratio of the matrix material to the nitrogen-containing compound is 1:1.5-3.5.

[0015] Preferably, the calcination temperature is 300-1200° C., and the holding time is 4-12 hours.

[0016] The present invention also provides a multi-level porous material prepared by the preparation method described in the above technical solution, wherein the multi-level porous material is a fluorine-nitrogen doped multi-level porous carbon material;

[0017] The multi-level pores include macroporous structure, mesoporous structure and microporous structure.

[0018] Preferably, the number of the macroporous structures accounts for 20-30% of the total number of pores; the number of the mesoporous structures accounts for 60-75% of the total number of pores; and the number of the microporous structures accounts for 1-10% of the total number of pores.

[0019] Preferably, the mass percentage of the fluorine is 1-10%; the mass percentage of the nitrogen is 5-15%.

[0020] The present invention also provides the use of the multi-level porous material described in the above technical solution in adsorption and filtration materials, catalyst carriers, drug carriers, high-temperature insulation materials, gas separation and chromatographic analysis.

[0021] The present invention provides a method for preparing a multi-level porous material, comprising the following steps: firstly mixing an ethylene polymer, a soluble metal salt, a fluorine-containing compound, and a polar organic solvent, followed by freeze-drying to obtain a base material; secondly mixing the base material and a nitrogen-containing compound, followed by calcination and acid leaching to obtain the multi-level porous material. The present invention forms a stable framework structure through freeze-drying, decomposes organic matter through calcination to generate gas, and causes the framework structure to generate a large number of pore structures, most of which are mesoporous structures, and a small portion are macroporous and microporous structures; by adding a fluorine-containing compound, the bonding between the raw materials can be enhanced, thereby further improving the strength of the multi-level porous material after calcination; finally, by acid leaching to wash away the metal, a microporous structure and a mesoporous structure can be generated, thereby making the structure of the obtained multi-level porous material more stable and less prone to structural collapse during application. DETAILED DESCRIPTION

[0022] The present invention provides a method for preparing a multi-level porous material, comprising the following steps:

[0023] The ethylene polymer, the soluble metal salt, the fluorine-containing compound and the polar organic solvent are mixed in one stage, and freeze-dried to obtain a matrix material;

[0024] The matrix material and the nitrogen-containing compound are mixed in two stages, and then calcined and acid-leached in sequence to obtain the porous material.

[0025] In the present invention, unless otherwise specified, all preparation raw materials are commercially available products well known to those skilled in the art.

[0026] The invention mixes ethylene polymer, soluble metal salt, fluorine-containing compound and polar organic solvent in one stage, and freeze-dries the mixture to obtain the matrix material.

[0027] In the present invention, the ethylene polymer preferably includes one or more of ethylene-vinyl acetate copolymer, polyethylene, and polyvinyl pyrrolidone. In the present invention, the polyethylene further preferably includes one or more of high-density polyethylene, low-density polyethylene, linear low-density polyethylene, and ultra-high molecular weight high-density polyethylene. In the present invention, the density of the high-density polyethylene is preferably 0.941 to 0.965; the density of the low-density polyethylene is preferably 0.926 to 0.94; the density of the linear low-density polyethylene is preferably 0.91 to 0.92; and the molecular weight of the ultra-high molecular weight high-density polyethylene is preferably 3 million to 6 million. In the present invention, the ethylene polymer, as a matrix material, can form a structurally stable framework structure during the freezing process.

[0028] In the present invention, the soluble metal salt includes one or more of zinc chloride, copper nitrate, ferric nitrate, copper carbonate, calcium sulfate, and ferrous sulfate. In the present invention, the soluble metal salt enables metal embedding within the framework structure, and subsequent acid leaching treatment creates microporous and mesoporous structures.

[0029] In the present invention, the fluorine-containing compound preferably includes one or more of polytetrafluoroethylene, calcium fluoride, hydrofluoric acid, sodium fluoride, uranium hexafluoride, sodium fluorosilicate and boron trifluoride.

[0030] In the present invention, the mass ratio of the ethylene polymer, the soluble metal salt and the fluorine-containing compound is preferably 1: (0.05-0.5): (0.5-1.5), more preferably 1: (0.1-0.45): (0.7-1.3), and more preferably 1: (0.15-0.4): (1.0-1.2).

[0031] In the present invention, the polar organic solvent preferably includes one or more of ethanol, methanol and tetrahydrofuran. In the present invention, the usage ratio of the ethylene polymer to the polar organic solvent is preferably 1.5 g:40 mL.

[0032] In the present invention, the temperature of the primary mixing is preferably 40-100°C, more preferably 50-90°C, and more preferably 60-80°C; the time is preferably 4-12 hours, more preferably 5-10 hours, and more preferably 6-8 hours. In the present invention, the primary mixing is preferably carried out under stirring conditions; the stirring speed is preferably 600 rpm.

[0033] After the primary mixing is completed, the present invention further preferably includes filtering the obtained material. The present invention has no particular limitation on the filtering process, and the filtering process can be performed using a process well known to those skilled in the art.

[0034] In the present invention, the freeze-drying temperature is preferably -20 to -5°C, more preferably -18 to -7°C, and even more preferably -15 to -10°C. The freeze-drying time is not particularly limited in the present invention, as long as the solvent in the mixed solution can be removed to obtain a dry matrix material. In the present invention, freeze-drying can produce a structurally stable framework structure.

[0035] After obtaining the base material, the present invention performs secondary mixing of the base material and the nitrogen-containing compound, and sequentially performs calcination and acid leaching treatment to obtain the multi-level porous material.

[0036] In the present invention, the nitrogen-containing compound preferably includes one or more of p-nitroaniline, benzidine, ethyleneimine, nitrosoamine, nitrosoamide and melamine. In the present invention, the nitrogen-containing compound can form more defect sites on the surface of the hierarchical porous material after calcination.

[0037] In the present invention, the mass ratio of the base material to the nitrogen-containing compound is preferably 1:1.5-3.5, more preferably 1:2.0-3.0, and even more preferably 1:2.2-2.8.

[0038] In the present invention, the secondary mixing method is preferably grinding. The present invention has no particular limitation on the grinding process, as long as the raw materials can be mixed uniformly.

[0039] In the present invention, the calcination is preferably carried out under a protective atmosphere; the protective atmosphere is preferably one or more of nitrogen, argon and helium.

[0040] In the present invention, the calcination temperature is preferably 300-1200°C, more preferably 400-1100°C, and more preferably 500-1000°C; the heating rate to the calcination temperature is preferably 5°C / min; the holding time is preferably 4-12h, more preferably 6-10h, and more preferably 8-9h.

[0041] After the calcination is completed, the present invention further preferably includes cooling the obtained material to room temperature. The present invention has no particular limitation on the cooling process, and the cooling process can be carried out using a process well known to those skilled in the art.

[0042] In the present invention, the acidic reagent used in the acid leaching treatment is preferably nitric acid. In the present invention, the concentration of the nitric acid is preferably 3 mol / L. In the present invention, the time of the acid leaching treatment is preferably 5 to 10 hours. The present invention does not specifically limit the amount of the acidic reagent used, and it can be carried out according to the process familiar to those skilled in the art. The present invention does not specifically limit the process of the acid leaching treatment, and it can be carried out according to the process familiar to those skilled in the art. The present invention can remove the metal elements in the product and the ash formed by calcination through acid leaching, thereby producing a rich microporous structure and mesoporous structure.

[0043] After the acid leaching treatment is completed, the present invention preferably further comprises washing and drying the obtained material. The present invention has no particular limitation on the washing and drying process, and can be carried out using processes well known to those skilled in the art.

[0044] The present invention forms a stable framework structure through freeze-drying. Calcination decomposes organic matter to generate gas, creating a large number of pores within the framework, most of which are mesoporous, with a small portion of macroporous and microporous structures. Finally, acid leaching removes the metal, creating microporous and mesoporous structures. This makes the resulting multi-level porous material more stable and less prone to structural collapse during application. Furthermore, the preparation method provided by the present invention is simple and suitable for industrial production.

[0045] The present invention also provides a multi-level porous material prepared by the preparation method described in the above technical solution, wherein the multi-level porous material is a fluorine-nitrogen doped multi-level porous carbon material;

[0046] The multi-level porous material comprises a macroporous structure, a mesoporous structure and a microporous structure.

[0047] In the present invention, the pore size of the macroporous structure is preferably 60 to 90 nm. In the present invention, the pore size of the mesoporous structure is preferably 20 to 35 nm. In the present invention, the pore size of the microporous structure is preferably 0.5 to 1.5 nm.

[0048] In the present invention, the number of the macroporous structure preferably accounts for 20-30% of the total pores, more preferably 23-28%. In the present invention, the number of the mesoporous structure preferably accounts for 60-75% of the total pores, more preferably 65-70%. In the present invention, the number of the microporous structure preferably accounts for 1-10% of the total pores, more preferably 2-8%.

[0049] In the present invention, the specific surface area of ​​the multi-level porous material is preferably 700 to 1300 m 2 / g, more preferably 800 to 1200 m 2 / g, more preferably 900 to 1100 m 2 / g.

[0050] In the present invention, the mass percentage of fluorine is preferably 1-10%, more preferably 2-9%, and more preferably 3-8%. In the present invention, the mass percentage of nitrogen is preferably 5-15%, more preferably 6-14%, and more preferably 7-13%.

[0051] The present invention utilizes fluorine atoms or fluorine-containing groups to replace hydrogen atoms in ethylene polymers to achieve fluorine doping of the multilevel porous material, thereby enhancing the lipophilicity of the multilevel porous material and further improving the biomembrane penetration ability of the multilevel porous material.

[0052] The present invention also provides the use of the multi-level porous material described in the above technical solution in the preparation of adsorption filter materials, catalyst carriers, drug carriers, high-temperature thermal insulation materials, gas separation, and chromatographic analysis. The present invention is not particularly limited to the specific implementation methods of the application, and those familiar to those skilled in the art can be used.

[0053] In order to further illustrate the present invention, a multi-level porous material provided by the present invention, its preparation method and application are described in detail below in conjunction with examples, but they should not be understood as limiting the scope of protection of the present invention.

[0054] Example 1

[0055] 1.8 g of ferrous sulfate, 2.4 g of polyvinyl pyrrolidone, 0.24 g of sodium fluoride and 60 mL of ethanol were stirred at 40° C. for 1 h at a stirring speed of 600 rpm and then filtered; the filtered material was freeze-dried at -10° C. to obtain a matrix material;

[0056] 1.2 g of the matrix material and 0.6 g of p-nitroaniline were ground and mixed uniformly, and then calcined at a heating rate of 5°C / min to 1000°C under a nitrogen atmosphere for 7 hours. After calcination, the mixture was cooled to room temperature and then acid-leached with 3 mol / L nitric acid for 8 hours. The multi-level porous material was then washed with water and dried.

[0057] The hierarchically porous material obtained in this example has a pore size of 60 nm for the macropore structure, 22 nm for the mesopore structure, and 0.6 nm for the micropore structure. The macropore structure accounts for 27%, the mesopore structure accounts for 68%, and the micropore structure accounts for 5%. The fluorine doping percentage is 2.3%, and the nitrogen doping percentage is 14.2%.

[0058] Example 2

[0059] 1.8 g of ferrous sulfate, 2.4 g of polyvinyl pyrrolidone, 0.34 g of sodium fluoride and 60 mL of ethanol were stirred at 40° C. for 1 h at a stirring speed of 600 rpm and then filtered; the filtered material was freeze-dried at -10° C. to obtain a matrix material;

[0060] 1.2 g of the matrix material and 0.6 g of p-nitroaniline were ground and mixed uniformly, and then calcined at a heating rate of 5°C / min to 1000°C under a nitrogen atmosphere for 7 hours. After calcination, the mixture was cooled to room temperature and then acid-leached with 3 mol / L nitric acid for 8 hours. The multi-level porous material was then washed with water and dried.

[0061] In the multi-level porous material obtained in this embodiment, the pore diameter of the macroporous structure is 62nm; the pore diameter of the mesoporous structure is 24nm; the pore diameter of the microporous structure is 0.7nm; the number ratio of the macroporous structure is 28%, the number ratio of the mesoporous structure is 67%, and the number ratio of the microporous structure is 5%; the fluorine doping percentage is 3.1%, and the nitrogen doping percentage is 13.3%.

[0062] Example 3

[0063] 1.8 g of ferrous sulfate, 2.4 g of polyvinyl pyrrolidone, 0.43 g of sodium fluoride and 60 mL of ethanol were stirred at 40° C. for 1 h at a stirring speed of 600 rpm and then filtered; the filtered material was freeze-dried at -10° C. to obtain a matrix material;

[0064] 1.2 g of the matrix material and 0.6 g of p-nitroaniline were ground and mixed uniformly, and then calcined at a heating rate of 5°C / min to 1000°C under a nitrogen atmosphere for 7 hours. After calcination, the mixture was cooled to room temperature and then acid-leached with 3 mol / L nitric acid for 8 hours. The multi-level porous material was then washed with water and dried.

[0065] In the multi-level porous material obtained in this embodiment, the pore diameter of the macroporous structure is 66nm; the pore diameter of the mesoporous structure is 26nm; the pore diameter of the microporous structure is 0.9nm; the number ratio of the macroporous structure is 25%, the number ratio of the mesoporous structure is 69% and the number ratio of the microporous structure is 6%; the fluorine doping percentage is 4.4%, and the nitrogen doping percentage is 13.8%.

[0066] Example 4

[0067] 1.8 g of ferrous sulfate, 2.4 g of polyvinyl pyrrolidone, 0.53 g of sodium fluoride and 60 mL of ethanol were stirred at 40° C. for 1 h at a stirring speed of 600 rpm and then filtered; the filtered material was freeze-dried at -10° C. to obtain a matrix material;

[0068] 1.2 g of the matrix material and 0.6 g of p-nitroaniline were ground and mixed uniformly, and then calcined at a heating rate of 5°C / min to 1000°C under a nitrogen atmosphere for 7 hours. After calcination, the mixture was cooled to room temperature and then acid-leached with 3 mol / L nitric acid for 8 hours. The multi-level porous material was then washed with water and dried.

[0069] In the multi-level porous material obtained in this embodiment, the pore diameter of the macroporous structure is 72nm; the pore diameter of the mesoporous structure is 29nm; the pore diameter of the microporous structure is 1.1nm; the number ratio of the macroporous structure is 29%, the number ratio of the mesoporous structure is 62% and the number ratio of the microporous structure is 9%; the fluorine doping percentage is 5.1%, and the nitrogen doping percentage is 12.3%.

[0070] Example 5

[0071] 1.8 g of ferrous sulfate, 2.4 g of polyvinyl pyrrolidone, 0.62 g of sodium fluoride and 60 mL of ethanol were stirred at 40° C. for 1 h at a stirring speed of 600 rpm and then filtered; the filtered material was freeze-dried at -10° C. to obtain a matrix material;

[0072] 1.2 g of the matrix material and 0.6 g of p-nitroaniline were ground and mixed uniformly, and then calcined at a heating rate of 5°C / min to 1000°C under a nitrogen atmosphere for 7 hours. After calcination, the mixture was cooled to room temperature and then acid-leached with 3 mol / L nitric acid for 8 hours. The multi-level porous material was then washed with water and dried.

[0073] In the multi-level porous material obtained in this embodiment, the pore diameter of the macroporous structure is 78nm; the pore diameter of the mesoporous structure is 32nm; the pore diameter of the microporous structure is 1.25nm; the number ratio of the macroporous structure is 28%, the number ratio of the mesoporous structure is 63% and the number ratio of the microporous structure is 9%; the fluorine doping percentage is 6.3%, and the nitrogen doping percentage is 13.6%.

[0074] Example 6

[0075] 1.8 g of ferrous sulfate, 2.4 g of polyvinyl pyrrolidone, 0.72 g of sodium fluoride and 60 mL of ethanol were stirred at 40° C. for 1 h at a stirring speed of 600 rpm and then filtered; the filtered material was freeze-dried at -10° C. to obtain a matrix material;

[0076] 1.2 g of the matrix material and 0.6 g of p-nitroaniline were ground and mixed uniformly, and then calcined at a heating rate of 5°C / min to 1000°C under a nitrogen atmosphere for 7 hours. After calcination, the mixture was cooled to room temperature and then acid-leached with 3 mol / L nitric acid for 8 hours. The multi-level porous material was then washed with water and dried.

[0077] In the multi-level porous material obtained in this embodiment, the pore diameter of the macroporous structure is 84nm; the pore diameter of the mesoporous structure is 34nm; the pore diameter of the microporous structure is 1.4nm; the number ratio of the macroporous structure is 30%, the number ratio of the mesoporous structure is 61% and the number ratio of the microporous structure is 9%; the fluorine doping percentage is 7.4%, and the nitrogen doping percentage is 14.1%.

[0078] Example 7

[0079] 1.8 g of ferrous sulfate, 3.1 g of polyvinyl pyrrolidone, 0.62 g of sodium fluoride and 60 mL of ethanol were stirred at 40° C. for 1 h at a stirring speed of 600 rpm and then filtered; the filtered material was freeze-dried at -10° C. to obtain a matrix material;

[0080] 1.2 g of the matrix material and 0.6 g of p-nitroaniline were ground and mixed uniformly, and then calcined at a heating rate of 5°C / min to 1000°C under a nitrogen atmosphere for 7 hours. After calcination, the mixture was cooled to room temperature and then acid-leached with 3 mol / L nitric acid for 8 hours. The multi-level porous material was then washed with water and dried.

[0081] In the multi-level porous material obtained in this embodiment, the pore diameter of the macroporous structure is 78nm; the pore diameter of the mesoporous structure is 32nm; the pore diameter of the microporous structure is 1.25nm; the number ratio of the macroporous structure is 27%, the number ratio of the mesoporous structure is 65% and the number ratio of the microporous structure is 8%; the fluorine doping percentage is 5.8%, and the nitrogen doping percentage is 12.6%.

[0082] Performance Testing

[0083] The multi-level porous materials obtained in Examples 1 to 7 were used to absorb lubricating oil. The test method was as follows: 1 g of the multi-level porous material was used to absorb lubricating oil, and the adsorption capacity of the multi-level porous material was tested. The test results are shown in Table 1.

[0084] Table 1 Adsorption test results of multi-level porous materials obtained in Examples 1 to 7

[0085] Example 1 Example 2 Example 3 Example 4 Adsorption capacity / g 7.8 7.2 8.8 6.8 Example 5 Example 6 Example 7 Adsorption capacity / g 6.5 6.3 6.5

[0086] It can be seen from Table 1 that the multi-level porous material provided by the present invention has good absorption of lubricating oil.

[0087] To further demonstrate the stability of the hierarchical porous material structure, the hierarchical porous materials obtained in Examples 1 to 7 were subjected to repeated lubricant oil absorption tests. The test method involved rinsing the oil-absorbing hierarchical porous materials with a large amount of water to completely remove the absorbed oil, then drying them, and finally allowing them to absorb the lubricant oil again. The test was repeated several times, and the test results are shown in Table 2.

[0088] Table 2 Test results of repeated oil absorption times of the multi-level porous materials obtained in Examples 1 to 7

[0089] Repeated oil absorption times / times Example 1 20 Example 2 17 Example 3 23 Example 4 15 Example 5 13 Example 6 12 Example 7 13

[0090] It can be seen from Table 2 that the multi-level porous material provided by the present invention can absorb lubricating oil repeatedly and has a strong structure.

[0091] Although the above embodiment provides a detailed description of the present invention, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a multi-level porous material, characterized in that: The following steps are involved: The ethylene polymer, the soluble metal salt, the fluorine-containing compound and the polar organic solvent are mixed in one stage, and freeze-dried to obtain a matrix material; The matrix material and the nitrogen-containing compound are mixed in two stages, and calcined and acid-leached in sequence to obtain the hierarchical porous material; The multi-level porous material is a fluorine-nitrogen doped multi-level porous carbon material; the multi-level pores include macroporous structures, mesoporous structures and microporous structures; the pore size of the macroporous structure is 60-90 nm, the pore size of the mesoporous structure is 20-35 nm, and the pore size of the microporous structure is 0.5-1.5 nm; the number of the macroporous structures accounts for 20-30% of the total number of pores; the number of the mesoporous structures accounts for 60-75% of the total number of pores; and the number of the microporous structures accounts for 1-10% of the total number of pores; The fluorine-containing compound includes one or more of polytetrafluoroethylene, calcium fluoride, hydrofluoric acid, sodium fluoride, uranium hexafluoride, sodium fluorosilicate and boron trifluoride.

2. The preparation method according to claim 1, characterized in that The ethylene polymer includes one or more of ethylene-vinyl acetate copolymer, polyethylene and polyvinyl pyrrolidone.

3. The preparation method according to claim 2, characterized in that The mass ratio of the ethylene polymer, the soluble metal salt and the fluorine-containing compound is 1:(0.05-0.5):(0.5-1.5).

4. The preparation method according to claim 3, characterized in that The freeze-drying temperature is -20 to -5°C.

5. The preparation method according to claim 1, characterized in that The nitrogen-containing compound includes one or more of p-nitroaniline, benzidine, ethyleneimine, nitrosoamines, nitrosoamides and melamine; The mass ratio of the matrix material to the nitrogen-containing compound is 1:1.5-3.

5.

6. The preparation method according to claim 5, characterized in that The calcination temperature is 300-1200° C., and the heat preservation time is 4-12 hours.

7. The multi-level porous material prepared by the preparation method according to any one of claims 1 to 6, characterized in that: The multi-level porous material is a fluorine-nitrogen doped multi-level porous carbon material; The multi-level pores include macroporous structure, mesoporous structure and microporous structure; The number of the macroporous structure accounts for 20-30% of the total number of pores; the number of the mesoporous structure accounts for 60-75% of the total number of pores; and the number of the microporous structure accounts for 1-10% of the total number of pores.

8. The multi-level porous material according to claim 7, characterized in that: The mass percentage of the fluorine is 1-10%; the mass percentage of the nitrogen is 5-15%.

9. Use of the multi-level porous material according to claim 7 or 8 in the preparation of adsorption filter materials, catalyst carriers, drug carriers, high-temperature insulation materials, gas separation and chromatographic analysis.