CN115216052B

CN115216052B - Preparation method of hierarchical pore MOFs material with complete framework

Info

Publication number: CN115216052B
Application number: CN202110432206.1A
Authority: CN
Inventors: 王洁欣; 王妮; 魏雁
Original assignee: Beijing University of Chemical Technology
Current assignee: Beijing University of Chemical Technology
Priority date: 2021-04-21
Filing date: 2021-04-21
Publication date: 2023-05-26
Anticipated expiration: 2041-04-21
Also published as: CN115216052A

Abstract

The invention discloses a preparation method of a hierarchical pore MOFs material with a complete framework, which comprises the following steps: dispersing MOFs material into a solvent, and marking as feed liquid A; dispersing a template agent into a solvent, and marking as a feed liquid B; mixing the feed liquid A and the feed liquid B to form a mixed dispersion; introducing the mixed dispersion obtained in the step S3 into a spray dryer for spray drying to obtain a mixed cluster body of MOFs material and template agent; and (3) dissolving the mixed cluster body obtained in the step (S4) in a liquid phase medium for etching, removing a template agent, and obtaining a product through centrifugation, washing and drying. The invention adopts spray drying technology, and then obtains the hierarchical pore MOFs material with regular morphology and controllable pore diameter through steps such as etching. The preparation method effectively realizes the preparation of the hierarchical pore MOFs material, and more than or equal to 70% of particles are in a spherical shape, and the particle size range of the particles is 1-10 mu m; the preparation process adopted by the invention is simple and is easy to realize large-scale production.

Description

Preparation method of hierarchical pore MOFs material with complete framework

Technical Field

The invention relates to the technical field of metal-organic framework material preparation; more particularly, it relates to a preparation method of hierarchical pore MOFs material with a complete framework.

Background

For twenty years, MOFs (metal-organic framework) is taken as a novel functional material, and has the characteristics of high specific surface area, low crystal density, permanent porosity, rich topological structure and the like, so that the MOFs are widely paid attention to by researchers at home and abroad. At present, MOFs materials have huge application prospects in the fields of gas storage, adsorption separation, drug transmission, energy conversion, super capacitors, catalysis and the like.

Most of the MOFs materials reported so far are microporous structures, and only a few MOFs materials have mesoporous structures. Although the pore structure of the material is favorable for adsorbing and separating small molecules, the rapid diffusion of molecules and the entering of larger molecules such as reactant molecules, product molecules, reaction intermediates, large-size drug molecules and the like into MOFs pore channels are also hindered, so that the practical application of MOFs materials is greatly limited, and the appearance of multistage pore MOFs opens up a new way for solving the problems.

The hierarchical pore MOFs material refers to MOFs material with at least two pore structures of micropores, mesopores and macropores, and compared with the traditional MOFs material with a single pore structure, the existence of micropores or small mesopores in the hierarchical pore MOFs material enables the material to still keep higher specific surface area and porosity, and the introduction of other mesopores and macropores is beneficial to rapid diffusion and free transportation of guest molecules in pore channels. In addition, the introduction of mesoporous and macroporous structures enables the hierarchical pore MOFs material to have larger pore volume, so that the hierarchical pore MOFs material has higher adsorption capacity.

The current methods for preparing the hierarchical pore MOFs material mainly comprise a ligand extension method, a ligand mixing method, a post-treatment method and the like. The extended ligand method combines long ligand with larger size structure with metal center to form larger pore canal; the post-treatment method is to remove part of the body or the metal center by heat treatment or the like to form defects. The operation flow of the methods is quite different, so that the morphology and the functions of the formed hierarchical pore MOFs material are quite different, but the operation process is easy to cause the collapse of the framework of the MOFs material. Therefore, a method for preparing the multistage pore MOFs material with the complete framework has the advantages of simple process, low energy consumption, short preparation time, controllable product particle size and relatively uniform morphology and pore diameter.

Disclosure of Invention

The invention aims to provide a preparation method of a hierarchical pore MOFs material with a complete framework. The method adopts a spray drying technology, and then the steps of etching and the like are carried out to obtain the hierarchical pore MOFs material with regular morphology and controllable pore diameter. The method effectively realizes the preparation of the hierarchical pore MOFs material, and more than or equal to 70% of particles are in a spherical shape, and the particle size range of the particles is 1-10 mu m; the preparation process adopted by the invention is simple and is easy to realize large-scale production.

In order to solve the technical problems, the invention adopts the following technical scheme:

a preparation method of a hierarchical pore MOFs material with a complete framework comprises the following steps:

s1, dispersing MOFs material into a solvent, and marking as feed liquid A;

s2, dispersing a template agent into a solvent, and marking as a feed liquid B;

s3, mixing the feed liquid A and the feed liquid B to form a mixed dispersion;

s4, introducing the mixed dispersion obtained in the step S3 into a spray dryer for spray drying to obtain a mixed cluster body of MOFs material and template agent;

s5, dissolving the mixed cluster body obtained in the step S4 in a liquid phase medium for etching, removing a template agent, and obtaining the hierarchical pore MOFs material through centrifugation, washing and drying.

As a further improvement of the technical scheme, in the steps S1, S2, the solvent is selected from one or more of the following substances: water, methanol, ethanol, N-dimethylformamide, toluene, tetrahydrofuran, ethylene glycol, cyclohexane.

Preferably, in step S1, the particle size of the MOFs material is 1-100nm; preferably, the MOFs material has a particle size of 5-50nm.

Preferably, in step S1, the solids content of feed liquid A is from 1 to 10% by weight, preferably from 2 to 5% by weight.

As a further improvement of the technical scheme, in step S2, the template agent is selected from one or more of the following substances: polystyrene, silica, mesoporous zeolite, alumina, cetyltrimethylammonium bromide, dodecanoic acid, F127, N-dimethyloctadecylamine, sodium 4-dodecylbenzoate.

Preferably, in the step S2, the particle size of the template agent is 20-600nm; preferably, the particle size of the template is 50-500nm.

Preferably, in step S2, the solid content of the feed liquid B is 1-8wt%, preferably 2-5wt%.

As a further improvement of the technical scheme, in the step S3, the mass ratio of the feed liquid A to the feed liquid B is 3:1-10:1.

Preferably, in step S3, the solution a and the solution B are mixed together by ultrasonic treatment for 4-6min.

As a further improvement of the solution, in step S4, the mixed dispersion is passed into a spray dryer with a peristaltic pump.

Preferably, in the step S4, the air speed of compressed air in the spray drying process is 300-800L/h; more preferably, the compressed air velocity during the spray drying is 400-650L/h.

Preferably, in the step S4, the input speed of the mixed dispersion in the spray drying process is 6-30mL/min; more preferably, the input speed of the mixed dispersion during the spray drying process is 10-23mL/min.

Preferably, in step S4, the temperature at the nozzle in the spray drying process is 90-160 ℃; more preferably, the temperature at the nozzle during the spray drying process is 100-140 ℃.

As a further improvement of the technical scheme, in step S5, the liquid phase medium is selected from one or more of the following substances: sodium hydroxide, hydrofluoric acid, toluene, N-dimethylformamide, tetrahydrofuran and ethanol.

Preferably, in step S5, the ratio of the mixed cluster body to the liquid medium is 1.5-6mg:1mL; preferably, the ratio of the mixed clusters to the liquid medium is 2-4.5mg:1mL.

Preferably, in step S5, the reaction condition of the etching is heating and stirring, the heating temperature is 25-100 ℃, and the reaction time is 0.5-10h.

Preferably, in step S5, the rotational speed of the centrifugation is 8000-12000rpm, and the time is 5-10min.

Any range recited in the invention includes any numerical value between the endpoints and any sub-range of any numerical value between the endpoints or any numerical value between the endpoints.

Unless otherwise indicated, all starting materials herein are commercially available, and the equipment used in the present invention may be conventional in the art or may be conventional in the art.

Compared with the prior art, the invention has the following beneficial effects:

1) In the prior art, regarding preparation of hierarchical pore MOFs materials, it is generally difficult to control pore size, and it is difficult to prepare MOFs materials having at least two pore structures of micropores, mesopores and macropores simultaneously while maintaining a complete MOFs framework. According to the invention, a spray drying process and an etching method are combined, and mesoporous particles formed among the particles and macropores formed by a template agent are removed by a spray drying process and an etching method, so that the multistage MOFs material with micro/mesoporous, controllable mesoporous and macropore of the material is constructed, and the particles are more than or equal to 70% and are spherical.

2) The preparation method of the invention has wide application range, and various MOFs materials and templates can be used as raw materials of the method; and the template agent can be easily and mildly removed by the etching method, so that the integrity of the MOFs material framework in the process is ensured.

3) The invention provides a simple method for regulating and controlling the pore diameter of macropores in a multistage-pore MOFs material, which can realize controllable preparation by only regulating one process condition. Namely, the preparation of MOFs materials with macropores of different sizes can be realized by spray drying the MOFs materials with the template agents of different particle sizes.

4) The method has the advantages of simple process flow, easy operation of experimental process, high production efficiency and easy realization of large-scale production.

Drawings

The following describes the embodiments of the present invention in further detail with reference to the drawings

FIG. 1 shows a Scanning Electron Microscope (SEM) image of a mixed cluster body and a hierarchical pore ZIF-8 obtained in example 1 of the present invention;

FIG. 2 shows a particle size distribution diagram of a hierarchical pore ZIF-8 obtained in example 1 of the present invention;

FIG. 3 shows an SEM image of a mixed cluster body and hierarchical pore ZIF-8 obtained in example 4 of the present invention;

FIG. 4 shows an SEM image of a mixed cluster body and hierarchical pore ZIF-8 obtained in example 6 of the present invention;

FIG. 5 shows an SEM image of a mixed cluster body and hierarchical pore ZIF-8 obtained in example 7 of the present invention;

FIG. 6 shows an SEM image of the product of comparative example 1 of the present invention;

FIG. 7 shows an SEM image of the product of comparative example 2 of the present invention;

fig. 8 shows SEM images of the product obtained in comparative example 3 of the present invention.

Detailed Description

In order to more clearly illustrate the present invention, the present invention will be further described with reference to preferred embodiments. It is to be understood by persons skilled in the art that the following detailed description is illustrative and not restrictive, and that this invention is not limited to the details given herein.

In the present invention, the term "hierarchical pore" means that at least two pore structures of micropores, mesopores and macropores exist at the same time.

In the present invention, the term "microwell" refers to a well having a pore diameter of less than 2 nm.

In the present invention, the term "mesoporous" refers to pores having a pore diameter of 2 to 50nm.

In the present invention, the term "macropores" refers to pores having a pore diameter of greater than 50nm.

As one aspect of the invention, the preparation method of the hierarchical pore MOFs material with the complete framework comprises the following steps:

s1, dispersing MOFs material into a solvent, and marking as feed liquid A;

s2, dispersing a template agent into a solvent, and marking as a feed liquid B;

s3, mixing the feed liquid A and the feed liquid B to form a mixed dispersion;

According to certain embodiments of the invention, in steps S1, S2, the solvent is selected from one or more of the following: water, methanol, ethanol, N-dimethylformamide, toluene, tetrahydrofuran, ethylene glycol, cyclohexane.

According to certain embodiments of the present invention, in step S1, the MOFs material has a particle size of 1-100nm; preferably, the MOFs material has a particle size of 5-50nm.

According to certain embodiments of the invention, in step S1, the solids content of feed liquid A is 1-10wt%.

According to certain preferred embodiments of the present invention, in step S1, the solids content of feed liquid a is 2-5wt%.

According to certain embodiments of the invention, in step S2, the templating agent is selected from one or more of the following: polystyrene, silica, mesoporous zeolite, alumina, cetyltrimethylammonium bromide, dodecanoic acid, F127, N-dimethyloctadecylamine, sodium 4-dodecylbenzoate.

According to certain embodiments of the present invention, in step S2, the particle size of the templating agent is 20-600nm; preferably, the particle size of the template is 50-500nm.

According to certain embodiments of the invention, in step S2, the solids content of the feed liquid B is 1-8wt%, preferably 2-5wt%.

According to certain embodiments of the present invention, in step S3, the mass ratio of the feed liquid a to the feed liquid B is 3:1 to 10:1.

According to certain embodiments of the present invention, in step S3, the feed liquid a is mixed with the feed liquid B using ultrasonic treatment for 4 to 6 minutes.

According to certain embodiments of the invention, in step S4, the mixed dispersion is passed into a spray dryer using a peristaltic pump.

According to certain embodiments of the present invention, in step S4, the compressed air velocity during the spray drying process is 300-800L/h.

According to certain preferred embodiments of the present invention, the compressed air velocity during the spray drying process is 400-650L/h.

According to certain embodiments of the invention, in step S4, the input speed of the mixed dispersion during the spray drying is 6-30mL/min.

According to certain preferred embodiments of the present invention, the input speed of the mixed dispersion during the spray drying process is 10-23mL/min.

According to certain embodiments of the invention, in step S4, the temperature at the nozzle during the spray drying is 90-160 ℃.

According to certain preferred embodiments of the invention, the temperature at the nozzle during the spray drying process is 100-140 ℃.

According to certain embodiments of the invention, in step S5, the liquid medium is selected from one or more of the following: sodium hydroxide, hydrofluoric acid, toluene, N-dimethylformamide, tetrahydrofuran and ethanol.

According to certain embodiments of the invention, in step S5, the ratio of the mixed cluster body to the liquid phase medium is 1.5-6mg:1mL.

According to certain preferred embodiments of the invention, the ratio of the mixed clusters to the liquid medium is 2-4.5mg:1mL.

According to some embodiments of the invention, in step S5, the etching is performed under the condition of heating and stirring, the heating temperature is 25-100 ℃, and the reaction time is 0.5-10h.

According to certain embodiments of the invention, in step S5, the centrifugation is performed at a rotational speed of 8000-12000rpm for a period of 5-10min.

Example 1

1) Preparing a feed liquid A: 100mL of ZIF-8 dispersion with a solid content of 2wt% was prepared, the dispersion medium was water, and the particle size of ZIF-8 in the dispersion was 20nm.

2) Preparing a feed liquid B: 25mL of a polystyrene dispersion having a solid content of 2wt% was prepared, the dispersion medium was water, and the particle size of the polystyrene in the dispersion was 300nm.

3) Mixing the feed liquid A and the feed liquid B, and carrying out ultrasonic mixing for 5min to obtain a mixed dispersion.

4) Introducing the mixed dispersion into a spray dryer by a peristaltic pump for spray drying; the spray drying adopts the following technological parameters: the input speed of the mixed dispersion is 17.1mL/min, the air speed of compressed air is 601L/h, the temperature at the nozzle is 110 ℃, and the mixed cluster body is obtained

5) The mixed clusters were dissolved in DMF solution and placed in a 80℃water bath with stirring for 1h, wherein the polystyrene to DMF ratio was 3.75mg/mL. The obtained product is centrifugally washed, DMF is washed once, methanol is washed twice, and the obtained wet solid is dried for 12 hours in a vacuum drying oven at 60 ℃ to obtain the hierarchical pore ZIF-8.

In FIG. 1, (a) shows an SEM image of a mixed cluster body obtained by spray drying, 80% of the cluster body has a spherical morphology, and the particle size ranges from 1 μm to 10 μm; in FIG. 1, (b) shows a morphology of the hierarchical pore ZIF-8 obtained after etching, wherein the pore diameter of the macropores is about 300nm, and the particle size of the polystyrene template is matched.

FIG. 2 shows the pore size distribution of the resulting hierarchical ZIF-8, and the presence of micropores and mesopores can be seen.

Example 2

4) Introducing the mixed dispersion into a spray dryer by a peristaltic pump for spray drying; the spray drying adopts the following technological parameters: the input speed of the mixed dispersion is 13.3mL/min, the air speed of the compressed air is 473L/h, the temperature at the nozzle is 100 ℃, and the mixed cluster body is obtained

5) The mixed clusters were dissolved in DMF solution and placed in a 70℃water bath with stirring for 1h, wherein the polystyrene to DMF ratio was 3mg/mL. The obtained product is centrifugally washed, DMF is washed once, methanol is washed twice, and the obtained wet solid is dried for 12 hours in a vacuum drying oven at 60 ℃ to obtain the hierarchical pore ZIF-8.

By changing the parameters of spray drying, the obtained hierarchical pore ZIF-8 has good appearance, most of the hierarchical pore ZIF-8 has a spherical shape, and the pore diameter of the macropores is about 300nm.

Example 3

1) Preparing a feed liquid A: 90mL of ZIF-8 dispersion having a solid content of 2wt% was prepared, the dispersion medium was water, and the particle size of ZIF-8 in the dispersion was 20nm.

2) Preparing a feed liquid B: 30mL of a polystyrene dispersion having a solid content of 2wt% was prepared, the dispersion medium was water, and the particle size of the polystyrene in the dispersion was 300nm.

4) Introducing the mixed dispersion into a spray dryer by a peristaltic pump for spray drying; the spray drying adopts the following technological parameters: the input speed of the mixed dispersion is 17.1mL/min, the air speed of the compressed air is 670L/h, the temperature at the nozzle is 120 ℃, and the mixed cluster body is obtained

5) The mixed clusters were dissolved in DMF solution and placed in a 80℃water bath with stirring for 1.5h, wherein the ratio of polystyrene to DMF was 3.75mg/mL. The obtained product is centrifugally washed, DMF is washed once, methanol is washed twice, and the obtained wet solid is dried for 12 hours in a vacuum drying oven at 60 ℃ to obtain the hierarchical pore ZIF-8.

The hierarchical pore ZIF-8 obtained in the embodiment has wider macroporous distribution and the pore diameter is about 300nm.

Example 4

2) Preparing a feed liquid B: 25mL of a polystyrene dispersion having a solid content of 2wt% was prepared, the dispersion medium was water, and the particle size of the polystyrene in the dispersion was 400nm.

4) Introducing the mixed dispersion into a spray dryer by a peristaltic pump for spray drying; the spray drying adopts the following technological parameters: the input speed of the mixed dispersion is 17.1mL/min, the air speed of the compressed air is 601L/h, the temperature at the nozzle is 100 ℃, and the mixed cluster body is obtained

In FIG. 3, (a) shows an SEM image of a mixed cluster body obtained by spray drying, 80% of the cluster body has a spherical morphology, and the particle size ranges from 1 μm to 10. Mu.m. In FIG. 3, (b) and (c) are SEM images of the hierarchical ZIF-8 obtained after etching, and the hierarchical ZIF-8 obtained in this example has a macropore diameter of about 400nm.

Example 5

1) Preparing a feed liquid A: 100mL of ZIF-8 dispersion having a solid content of 3wt% was prepared, the dispersion medium was water, and the particle size of ZIF-8 in the dispersion was 20nm.

2) Preparing a feed liquid B: 25mL of a polystyrene dispersion having a solid content of 3wt% was prepared, the dispersion medium was water, and the particle size of the polystyrene in the dispersion was 400nm.

4) Introducing the mixed dispersion into a spray dryer by a peristaltic pump for spray drying; the spray drying adopts the following technological parameters: the input speed of the mixed dispersion is 17.1mL/min, the air speed of the compressed air is 414L/h, the temperature at the nozzle is 100 ℃, and the mixed cluster body is obtained

5) The mixed clusters were dissolved in DMF solution and placed in a 80℃water bath with stirring for 1h, wherein the ratio of polystyrene to DMF was 2.5mg/mL. The obtained product is centrifugally washed, DMF is washed once, methanol is washed twice, and the obtained wet solid is dried for 12 hours in a vacuum drying oven at 60 ℃ to obtain the hierarchical pore ZIF-8.

The hierarchical pore ZIF-8 obtained in this example was similar to that obtained in example 1.

Example 6

1) Preparing a feed liquid A: 100mL of ZIF-8 dispersion having a solid content of 2wt% was prepared, the dispersion medium was water, and the particle size of ZIF-8 in the dispersion was 30nm.

4) Introducing the mixed dispersion into a spray dryer by a peristaltic pump for spray drying; the spray drying adopts the following technological parameters: the input speed of the mixed dispersion is 20.9mL/min, the air speed of compressed air is 601L/h, the temperature at the nozzle is 100 ℃, and the mixed cluster body is obtained

5) The mixed clusters were dissolved in DMF solution and placed in a 90℃water bath with stirring for 1h, wherein the ratio of polystyrene to DMF was 3.75mg/mL. The obtained product is centrifugally washed, DMF is washed once, methanol is washed twice, and the obtained wet solid is dried for 12 hours in a vacuum drying oven at 60 ℃ to obtain the hierarchical pore ZIF-8.

In FIG. 4, (a) shows an SEM image of a mixed cluster body obtained by spray drying, 80% of the cluster body has a spherical morphology, and the particle size ranges from 1 μm to 10. Mu.m.

In FIG. 4, (b) shows an SEM image of a hierarchical ZIF-8 obtained after etching, the macropore pore diameter is about 400nm, and the embodiment changes the particle size of the feed liquid A, and the hierarchical ZIF-8 skeleton can be maintained after the template is removed by etching.

Example 7

1) Preparing a feed liquid A: 100mL of ZIF-8 dispersion having a solid content of 2wt% was prepared, the dispersion medium was water, and the particle size of ZIF-8 in the dispersion was 15nm.

2) Preparing a feed liquid B: 25mL of a polystyrene dispersion having a solid content of 2wt% was prepared, the dispersion medium was water, and the particle size of the polystyrene in the dispersion was 100nm.

In FIG. 5, (a) shows an SEM image of a mixed cluster body obtained by spray drying, 80% of the cluster body has a spherical morphology, and the particle size ranges from 1 μm to 10. Mu.m. In FIG. 5, (b) shows an SEM image of the hierarchical pore ZIF-8 obtained after etching, with a macropore pore diameter of about 100nm.

Example 8

Example 1 was repeated except that in step 1), ZIF-8 was used as MIL-101, uiO-66, ZIF-67, ZIF-90, MOF-801, MIL-100, MIL-53, uiO-66-NH ₂ 、UiO-66-SO ₃ H. One of UiO-66-COOH.

The result was similar to example 1.

Example 9

Example 1 was repeated except that in step 1), the ZIF-8 was replaced with one of HKUST-1, MOF-5, MOF-74; the dispersion medium is ethanol. In step 2), the dispersion medium is ethanol.

The result was similar to example 1.

Comparative example 1

A hierarchical pore MOFs material was prepared using the procedure as described in example 1, except that: in step 2) 50mL of a polystyrene dispersion having a solids content of 2wt% are formulated.

As shown in FIG. 6, which is an SEM image of the product obtained in comparative example 1, it was difficult to maintain the complete ZIF-8 skeleton structure after etching due to the mass ratio of ZIF-8 to polystyrene being 2:1, resulting in breakage.

Comparative example 2

A hierarchical pore MOFs material was prepared using the procedure as described in example 2, except that: the temperature at the nozzle in step 4) was 160 ℃.

As shown in fig. 7, which is an SEM image of the product obtained in comparative example 2, the temperature at the nozzle was too high, resulting in about 30% of the clusters formed after spray drying being spherical, and the cracking was severe after etching.

Comparative example 3

A hierarchical pore MOFs material was prepared using the procedure as described in example 3, except that: the particle size of the polystyrene in step 2) was 800nm.

As shown in fig. 8, which is an SEM image of the product obtained in comparative example 3, the clusters formed by spray drying are supported by the template agent due to the oversized particle size of the template agent, and collapse of MOFs skeleton is also caused after etching.

Comparative example 4

A hierarchical pore MOFs material was prepared using the procedure described in example 4, except that: in the step 3), the feed liquid A and the feed liquid B are directly mixed without ultrasonic treatment.

Agglomeration of the template agent is easy to cause in the spray drying process, and the pore structure of the obtained hierarchical pore MOFs material is unevenly distributed.

Comparative example 5

A hierarchical pore MOFs material was prepared using the procedure described in example 6, except that: the etching temperature in step 5) was 200 ℃.

The temperature used in the etching process is too high, so that the polystyrene template agent is adhered to the surface of the hierarchical pore ZIF-8 after being removed.

It is to be understood that the above examples of the present invention are provided by way of illustration only and not by way of limitation of the embodiments of the present invention. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. Not all embodiments are exhaustive. All obvious changes or modifications which come within the spirit of the invention are desired to be protected.

Claims

1. The preparation method of the hierarchical pore MOFs material capable of maintaining the complete framework is characterized by comprising the following steps of:

s1, dispersing MOFs material into a solvent, and marking as feed liquid A; the particle size of the MOFs material is 1-100nm;

s2, dispersing a template agent into a solvent, and marking as a feed liquid B; the particle size of the template agent is 20-600nm;

s3, mixing the feed liquid A and the feed liquid B to form a mixed dispersion; the mass ratio of the feed liquid A to the feed liquid B is 3:1-10:1, and ultrasonic treatment is performed for 4-6min when the feed liquid A and the feed liquid B are mixed;

s4, introducing the mixed dispersion obtained in the step S3 into a spray dryer for spray drying to obtain a mixed cluster body of MOFs material and template agent; the temperature of the nozzle in the spray drying process is 100-140 ℃;

s5, dissolving the mixed cluster body obtained in the step S4 in a liquid phase medium for etching, removing a template agent, and obtaining the hierarchical pore MOFs material through centrifugation, washing and drying; the etching reaction conditions are heating and stirring, the heating temperature is 25-100 ℃, and the reaction time is 0.5-10h.

2. The method for preparing the hierarchical porous MOFs material according to claim 1, wherein the steps of: in the steps S1 and S2, the solvent is selected from one or more of the following substances: water, methanol, ethanol, N-dimethylformamide, toluene, tetrahydrofuran, ethylene glycol, cyclohexane.

3. The method for preparing the hierarchical porous MOFs material according to claim 1, wherein the steps of: in the step S1, the particle size of the MOFs material is 5-50nm.

4. The method for preparing the hierarchical porous MOFs material according to claim 1, wherein the steps of: in the step S1, the solid content of the feed liquid A is 1-10wt%.

5. The method for preparing the hierarchical porous MOFs material according to claim 4, wherein the steps of: in the step S1, the solid content of the feed liquid A is 2-5wt%.

6. The method for preparing the hierarchical porous MOFs material according to claim 1, wherein the steps of: in step S2, the template agent is selected from one or more of the following substances: polystyrene, silicon dioxide, mesoporous zeolite, alumina, cetyltrimethylammonium bromide, dodecanoic acid, N-dimethyl octadecyl amine, and sodium 4-dodecyl benzoate.

7. The method for preparing the hierarchical porous MOFs material according to claim 1, wherein the steps of: in the step S2, the particle size of the template agent is 50-500nm.

8. The method for preparing the hierarchical porous MOFs material according to claim 1, wherein the steps of: in the step S2, the solid content of the feed liquid B is 1-8 wt%.

9. The method for preparing the hierarchical porous MOFs material according to claim 8, wherein the steps of: in the step S2, the solid content of the feed liquid B is 2-5wt%.

10. The method for preparing the hierarchical porous MOFs material according to claim 1, wherein the steps of: in step S4, introducing the mixed dispersion into a spray dryer by a peristaltic pump;

in the step S4, the air speed of compressed air in the spray drying process is 300-800L/h;

in step S4, the input speed of the mixed dispersion in the spray drying process is 6-30mL/min.

11. The method for preparing the hierarchical porous MOFs material according to claim 10, wherein the steps of:

in the step S4, the air speed of compressed air in the spray drying process is 400-650L/h;

in step S4, the input speed of the mixed dispersion in the spray drying process is 10-23mL/min.

12. The method for preparing the hierarchical porous MOFs material according to claim 1, wherein the steps of: in step S5, the liquid medium is selected from one or more of the following: hydrofluoric acid, toluene, N-dimethylformamide, tetrahydrofuran and ethanol;

in step S5, the ratio of the mixed cluster body to the liquid phase medium is 1.5-6mg:1mL.

13. The method for preparing the hierarchical porous MOFs material according to claim 12, wherein:

in step S5, the ratio of the mixed cluster body to the liquid phase medium is 2-4.5mg:1mL.