Preparation and electromagnetic performance application of FeSiO3-coated COF hollow composite nanospheres
FeSiO3@COF hollow composite nanospheres were prepared by template method and hydrothermal-calcination method, which solved the problems of lightweight and high temperature resistance of microwave absorbing materials and achieved wideband and high-efficiency electromagnetic performance.
Patent Information
- Application Number
- CN202511449819.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-11
- Publication Date
- 2026-01-02
AI Technical Summary
Existing microwave absorbing materials cannot simultaneously meet the requirements of wide bandwidth, high efficiency and thinness, and microwave transparent materials lack lightweight and high temperature resistance.
SiO2 particles were synthesized by template method and grafted onto lightweight organic material COF. FeSiO3@COF and Fe2(SiO3)3@COF hollow composite materials were prepared by hydrothermal reaction and calcination method. The reaction temperature and time were controlled to ensure the stability of the materials.
High-temperature resistant, lightweight FeSiO3@COF hollow composite nanospheres were prepared, exhibiting excellent electromagnetic properties and suitable for electromagnetic wave transmission and absorption.
Smart Images
Figure CN121244210A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of functional material preparation technology, specifically relating to the preparation method of FeSiO3@COF hollow composite nanospheres, their products, and applications. Background Technology
[0002] With the development of science and technology and wireless communication technology, electromagnetic pollution has become a new environmental problem. Currently, the most effective method to prevent electromagnetic radiation is to use absorbing materials. High-performance absorbing materials need to simultaneously meet the characteristics of wide bandwidth, high efficiency, and thinness. Paradoxically, high-efficiency absorbing materials are often composed of two different types of materials: wave-transmitting materials and absorbers. Therefore, the design of composite absorbing materials has always attracted attention. Wave-transmitting materials, as one of the components of absorbing materials, must also consider the characteristics of being "light and thin." In the chemical industry, lightweight materials such as hollow CdS, ZrO2, carbon spheres, and TiO2 are often synthesized through methods such as template methods, ultrasonic chemical methods, and hydrothermal methods. Wave-transmitting materials are responsible for transmitting electromagnetic waves and include organic and inorganic wave-transmitting materials. Inorganic wave-transmitting materials usually refer to composite materials of ceramic materials, glass, or various fibers, doped with components such as CrO2 and TiO2 with moderate electrical properties. Organic materials generally have a higher dielectric constant than inorganic materials, but they are not resistant to high temperatures. Therefore, designing and synthesizing lightweight and high-temperature resistant wave-transmitting materials is also an important part of preparing composite absorbing materials. This invention provides a controllable synthesis of FeSiO3@COF and Fe2(SiO3)3@COF hollow composite materials with advantages of high temperature resistance and light weight. First, uniformly sized SiO2 particles are obtained using a template method. Second, the SiO2 particles are grafted onto a lightweight organic material called COF. Third, hollow FeSiO3@COF and Fe2(SiO3)3@COF are obtained by controlling the hydrothermal reaction time and temperature using the hydrothermal hydrolysis of metal salts and silicon dioxide under alkaline conditions. Finally, calcination is used to obtain morphologically stable, high-temperature resistant FeSiO3@COF and Fe2(SiO3)3@COF hollow composite materials, and the electromagnetic properties of these two coaxial ring samples are tested. Summary of the Invention
[0003] In view of this, one objective of the present invention is to provide a method for preparing FeSiO3@COF hollow composite nanospheres; a second objective of the present invention is to provide FeSiO3@COF hollow composite nanospheres; and a third objective of the present invention is to provide an application of FeSiO3@COF hollow composite nanospheres in terms of electromagnetic properties.
[0004] To achieve the above objectives, the present invention provides the following technical solution:
[0005] 1. A method for preparing a FeSiO3@COF composite nanomaterial catalyst, characterized in that the preparation method includes the following steps:
[0006] (1) Preparation of Fe2O3
[0007] Fe2O3 was prepared by heating under reflux using FeCl3·6H2O, urea, and tetrabutylammonium bromide as raw materials. After drying, the Fe2O3 was ground and then calcined at 600 °C in air to obtain brick-red Fe2O3 nanomaterials.
[0008] (2) Preparation of amorphous Fe2O3@Ni-MOF
[0009] Fe₂O₃, 4,4'-bipyridine (Bpy), 2,5-thiophene dicarboxylic acid (Tdc), and polyvinylpyrrolidone (PVP) were dispersed in anhydrous ethanol and water and stirred. NaOH solution and Ni were then added dropwise. 2+ The solution was transferred to a reaction vessel and reacted for 2 hours.
[0010] (3) Preparation of crystallized Fe2O3@Ni-MOF
[0011] Finally, the ground Fe2O3@Ni-MOF product was placed in a crucible and calcined at 400 °C for 2 h in air atmosphere to obtain crystallized Fe2O3@Ni-MOF.
[0012] Preferably, in step (1), the molar ratio of zirconium tetrachloride, 1,4-terephthalic acid and acrylamide is 1~2:12~24:6~12.
[0013] Preferably, in step (1), the organic solvent is any one of N,N-dimethylformamide, dimethyl sulfoxide, toluene, or chloroform.
[0014] Preferably, in step (1), the drying is performed at a temperature of 50~70℃ for 1~2 h; in step (1), the cleaning and filtration specifically involves: repeatedly rinsing with deionized water and anhydrous ethanol, drying at 50~70℃ for 1~2 h, transferring to a methanol solution, oscillating at a constant temperature for 1~2 h, and then filtration and rinsing; in step (1), the drying temperature is 80~90℃.
[0015] Preferably, in step (2), the initiator is potassium persulfate, azobisisobutyronitrile (AIBN), or azobisisobutyramidine hydrochloride (AIBA).
[0016] Preferably, in step (2), the crosslinking agent is ethylene glycol dimethacrylate (EGDMA) and p-vinylbenzene, and the particle size of the styrene is 260~390 nm.
[0017] Preferably, in step (2), the ratio of polystyrene, MOF-NH2 powder, initiator, anhydrous DMSO, styrene (St) and crosslinking agent is 50~100:50~100:27~54:60~100:0.35~1.4:0.1~0.2, mg:mg:mg:mL:mL:mL.
[0018] Preferably, in step (3), the eluent is any one or more of THF, DMF, CCl3 or toluene;
[0019] Preferably, in step (3), the ultrasonic stirring specifically involves ultrasonic stirring for 1-20 min followed by stirring for 1-4 h.
[0020] 2. Fe2O3@Ni-MOF composite nanomaterial catalyst prepared according to any one of the above preparation methods.
[0021] 3. Application of Fe2O3@Ni-MOF composite nanomaterial catalyst in adsorption of dye wastewater.
[0022] The beneficial effects of this invention are as follows: This invention employs a simple hydrothermal-calcination method to prepare a series of Ni-COF / Fe2O3 composite nanomaterial catalysts. First, the compositionally optimized catalyst Ni-COF / Fe2O3-1 exhibits excellent electrocatalytic performance and stability for OER (Optimal Energy Emission Reduction), which may be due to the synergistic effect between the two structurally different oxides, which is beneficial to improving the activity of the composite nanomaterial catalyst. Second, the mesoporous structure of the catalyst also facilitates charge transport, thereby improving the electrocatalytic activity of the catalyst. The strategy provided in this work can be widely applied to the design and preparation of other composite materials for clean energy conversion and storage technologies.
[0023] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description
[0024] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:
[0025] Figure 1 This is a flowchart illustrating the preparation of FeSiO3@COF hollow composite nanospheres according to the present invention;
[0026] Figure 2 This is a SEM image of the FeSiO3@COF hollow composite nanospheres prepared in Example 1;
[0027] Figure 3 This is a TEM image of the FeSiO3@COF hollow composite nanospheres prepared in Example 1;
[0028] Figure 4 The elemental mapping diagram of the FeSiO3@COF hollow composite nanospheres prepared in Example 1;
[0029] Figure 5 The XRD pattern of the FeSiO3@COF hollow composite nanospheres prepared in Example 1;
[0030] Figure 6 This is a comparison diagram of the pore size distribution of FeSiO3@COF prepared in Example 1 and Fe2(SiO3)3@COF hollow composite nanospheres prepared in Example 2;
[0031] Figure 7 The composite dielectric constant and magnetic permeability constant of the FeSiO3@COF prepared in Example 1 and the Fe2(SiO3)3@COF hollow composite nanospheres prepared in Example 2. Detailed Implementation
[0032] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.
[0033] Example 1
[0034] A Fe2O3@Ni-MOF composite nanomaterial catalyst (P(St&AM)MOF-1) is prepared by the following steps:
[0035] (1) Preparation of MOF-NH2: 1 mmol zirconium tetrachloride, 12 mmol 1,4-terephthalic acid and 6 mmol acrylamide were dissolved in 60 mL N,N-dimethylformamide and magnetically stirred at room temperature to form a mixed solution. The mixed solution was transferred to a hydrothermal reactor and hydrothermally reacted at 120 °C for 24 h. After cooling to room temperature, the mixture was washed several times with deionized water and anhydrous ethanol, and dried at 70 °C for 1 h. The product obtained above was added to 30 mL methanol solution and placed in a constant temperature shaker and continuously shaken at 120 r / min for 1 h. After vacuum filtration, the mixture was washed three times each with deionized water and anhydrous ethanol, and dried at 90 °C to obtain a white powder, which is MOF-NH2 powder (abbreviated as MOF), for later use.
[0036] (2) Preparation of PS@P(St&AM)MOF: 100 mg of polystyrene (with a particle size range of 275±15 nm) was added to a 150 mL three-necked flask equipped with a magnetic stirrer, along with 50 mg of MOF-NH2 powder and 27 mg of azobisisobutyronitrile (AIBN). The flask was dehydrated and deoxygenated three times under vacuum N2 displacement to form an anhydrous and oxygen-free condition. After adding 60 mL of dehydrated DMSO, 0.35 mL of styrene (St) and 0.1 mL of ethylene glycol dimethacrylate (EGDMA) were added dropwise. The mixture was reacted in an oil bath at 120 °C for 24 h. After cooling to room temperature, the mixture was washed with deionized water (3×30 mL) and anhydrous ethanol (3×30 mL) in sequence. After centrifugation, the mixture was air-dried to obtain PS@P(St&AM)MOF.
[0037] (3) Preparation of Fe2O3@Ni-MOF composite nanomaterial catalyst: Take 100 mg of PS@P(St&AM)MOF prepared in step (2) above, disperse it in 50 mL THF, sonicate for 10 min and stir for 3 h to remove the core, and centrifuge to obtain 72 mg of Fe2O3@Ni-MOF-1 composite nanomaterial microspheres.
[0038] Example 2
[0039] A Fe2O3@Ni-MOF composite nanomaterial catalyst, the specific preparation method includes the following steps:
[0040] Replace "dissolve 1 mmol zirconium tetrachloride, 12 mmol 1,4-terephthalic acid, and 6 mmol acrylamide in 60 mL N,N-dimethylformamide" in step (1) of Example 1 with "dissolve 1 mmol zirconium tetrachloride, 24 mmol 1,4-terephthalic acid, and 12 mmol acrylamide in 80 mL N,N-dimethylformamide". Replace step (2) of Example 1 with "(2) Preparation of PS@P(St&AM)MOF: Add 100 mg of polystyrene as the core (the particle size range of the polystyrene core is 275±15 nm), 50 mg of MOF-NH2 powder prepared in step (1) above, and 27 mg of azobisisobutyronitrile (AIBN) to a 150 mL three-necked flask equipped with a magnetic stirrer. After three dehydration and deoxygenation under vacuum N2 displacement to form an anhydrous and oxygen-free condition, add 60 mL of dehydrated DMSO and then add 0.35 mg of styrene (St) dropwise." The mixture was prepared by reacting 0.1 mL of ethylene glycol dimethacrylate (EGDMA) with 0.1 mL of deionized water and anhydrous ethanol (3×30 mL) in an oil bath at 120 °C for 24 h. After cooling to room temperature, the mixture was washed with deionized water (3×30 mL) and anhydrous ethanol (3×30 mL) in sequence. After centrifugation and air drying, the PS@P(St&AM)MOF composite material was obtained. The remaining conditions and methods were the same as in Example 1, and 88 mg of Fe2O3@Ni-MOF composite nanomaterial catalyst was prepared.
[0041] Example 3
[0042] A Fe2O3@Ni-MOF composite nanomaterial catalyst, the specific preparation method includes the following steps:
[0043] Replace "dissolve 1 mmol zirconium tetrachloride, 12 mmol 1,4-terephthalic acid, and 6 mmol acrylamide in 60 mL N,N-dimethylformamide" in step (1) of Example 1 with "dissolve 2 mmol zirconium tetrachloride, 12 mmol 1,4-terephthalic acid, and 6 mmol acrylamide in 40 mL N,N-dimethylformamide". Replace step (2) of Example 1 with "(2) Preparation of PS@P(St&AM)MOF: Add 100 mg of polystyrene as the core (the particle size range of the polystyrene core is 275±15 nm), 50 mg of MOF-NH2 powder prepared in step (1) above, and 27 mg of azobisisobutyronitrile (AIBN) to a 150 mL three-necked flask equipped with a magnetic stirrer. After three dehydration and deoxygenation under vacuum N2 displacement to form an anhydrous and oxygen-free condition, add 60 mL of dehydrated DMSO and then add 0.35 mg of styrene (St) dropwise." The mixture was prepared by reacting 0.1 mL of ethylene glycol dimethacrylate (EGDMA) in an oil bath at 120 °C for 24 h, cooling to room temperature, and then washing with deionized water (3 × 30 mL) and anhydrous ethanol (3 × 30 mL) in sequence. After centrifugation and air drying, the PS@P(St&AM)MOF composite material was obtained. The remaining conditions and methods were the same as in Example 1, and 70 mg of Fe2O3@Ni-MOF composite nanomaterial catalyst was prepared.
[0044] Example 4
[0045] A Fe2O3@Ni-MOF composite nanomaterial catalyst (P(St&AM)MOF-2) is prepared by the following steps:
[0046] In step (2) of Example 1, “0.35 mL of styrene (St)” was replaced with “0.7 mL of styrene (St)”, and the other conditions and methods were the same as in Example 1. 81 mg of the erythroid-like structure P(St&AM)MOF-2 composite material was prepared.
[0047] Example 5
[0048] A Fe2O3@Ni-MOF composite nanomaterial catalyst, the specific preparation method includes the following steps:
[0049] In step (2) of Example 2, “27 mg azobisisobutyronitrile (AIBN)” was changed to “13 mg potassium persulfate”, and the remaining conditions and methods were the same as in Example 2, to prepare 78 mg of Fe2O3@Ni-MOF composite nanomaterial catalyst.
[0050] Example 6
[0051] A Fe2O3@Ni-MOF composite nanomaterial catalyst, the specific preparation method includes the following steps:
[0052] In step (2) of Example 3, “27 mg azobisisobutyronitrile (AIBN)” was changed to “13 mg potassium persulfate”, and the remaining conditions and methods were the same as in Example 3, to prepare 81 mg of Fe2O3@Ni-MOF composite nanomaterial catalyst.
[0053] Example 7
[0054] A Fe2O3@Ni-MOF composite nanomaterial catalyst, the specific preparation method includes the following steps:
[0055] In steps (2) of Examples 5 and 6, “0.35 mL of styrene (St)” was changed to “0.7 mL of styrene (St)”, and the remaining conditions and methods were the same as in Examples 5 and 6, to prepare 83 mg of Fe2O3@Ni-MOF composite nanomaterial catalyst.
[0056] Example 8
[0057] A Fe2O3@Ni-MOF composite nanomaterial catalyst, the specific preparation method includes the following steps:
[0058] In step (2) of Example 2, “27 mg azobisisobutyronitrile (AIBN)” was modified to “29 mg azobisisobutyramidine hydrochloride (AIBA)”, and the remaining conditions and methods were the same as in Example 2, to prepare 80 mg of Fe2O3@Ni-MOF composite nanomaterial catalyst.
[0059] Example 9
[0060] A Fe2O3@Ni-MOF composite nanomaterial catalyst, the specific preparation method includes the following steps:
[0061] In step (2) of Example 3, “27 mg azobisisobutyronitrile (AIBN)” was modified to “29 mg azobisisobutyramidine hydrochloride (AIBA)”, and the remaining conditions and methods were the same as in Example 3, to prepare 82 mg of Fe2O3@Ni-MOF composite nanomaterial catalyst.
[0062] Example 10
[0063] A Fe2O3@Ni-MOF composite nanomaterial catalyst, the specific preparation method includes the following steps:
[0064] In steps (2) of Examples 8 and 9, “0.35 mL of styrene (St)” was changed to “0.7 mL of styrene (St)”, and the remaining conditions and methods were the same as in Examples 8 and 9, respectively, to prepare 93 mg of Fe2O3@Ni-MOF composite nanomaterial catalyst.
[0065] Example 11
[0066] In step (2) of Example 2, “0.1 mL of ethylene glycol dimethacrylate (EGDMA)” was modified to “0.34 mg of p-vinylbenzene”. The remaining conditions and methods were the same as in Example 2, and 74 mg of Fe2O3@Ni-MOF composite nanomaterial catalyst was prepared.
[0067] Example 12
[0068] In step (2) of Example 3, “0.1 mL of ethylene glycol dimethacrylate (EGDMA)” was changed to “0.68 mg of p-vinylbenzene”. The remaining conditions and methods were the same as in Example 3, and 76 mg of Fe2O3@Ni-MOF composite nanomaterial catalyst was prepared.
[0069] Example 13
[0070] A Fe2O3@Ni-MOF composite nanomaterial catalyst, the specific preparation method includes the following steps:
[0071] In steps (2) of Examples 11 and 12, “0.35 mL of styrene (St)” was changed to “0.7 mL of styrene (St)”, and the remaining conditions and methods were the same as in Examples 11 and 12, respectively, to prepare 89 mg of Fe2O3@Ni-MOF composite nanomaterial catalyst. Attached Figure Description
[0072] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:
[0073] Figure 1 This is a flowchart illustrating the preparation of FeSiO3@COF hollow composite nanospheres according to the present invention;
[0074] Figure 2 This is a SEM image of the FeSiO3@COF hollow composite nanospheres prepared in Example 1;
[0075] Figure 3 This is a TEM image of the FeSiO3@COF hollow composite nanospheres prepared in Example 1;
[0076] Figure 4The elemental mapping diagram of the FeSiO3@COF hollow composite nanospheres prepared in Example 1;
[0077] Figure 5 The XRD pattern of the FeSiO3@COF hollow composite nanospheres prepared in Example 1;
[0078] Figure 6 This is a comparison diagram of the pore size distribution of FeSiO3@COF prepared in Example 1 and Fe2(SiO3)3@COF hollow composite nanospheres prepared in Example 2;
[0079] Figure 7 The composite dielectric constant and magnetic permeability constant of the FeSiO3@COF prepared in Example 1 and the Fe2(SiO3)3@COF hollow composite nanospheres prepared in Example 2.
[0080] 2. Electromagnetic property analysis of FeSiO3@COF hollow composite nanospheres
[0081] Figure 7 Sample 'ad' represents coaxial ring samples of Fe2(SiO3)3@COF and FeSiO3@COF, and their composite dielectric constant and permeability constant were measured. Sample 1 is a mixture of Fe2(SiO3)3@COF and paraffin, and Sample 2 is a mixture of FeSiO3@COF and paraffin. (Comparison) Figure 7 Figure 7a shows that the real part of the dielectric constant of sample 2 is reduced, with the highest value decreasing from 2.77 to 2.68. In the 1-7 GHz frequency range, both the real and imaginary parts of the dielectric constant of sample 1 are higher than those of sample 2. In the 7-9 GHz frequency range, the composite dielectric constant of sample 1 is relatively stable, while both the real and imaginary parts of the dielectric constant of sample 2 show large fluctuations, especially the imaginary part of the dielectric constant shows a maximum value of 0.38 (Figure 7b). Figure 7 Figures c and 7d show that both the real and imaginary parts of the permeability of sample 2 are reduced, with the real part closer to 1. The reduction in the imaginary part of the permeability is beneficial for the sample's wave transmission. Therefore, overall, sample 1 exhibits good wave transmission in the 1-9 GHz range. Sample 2 shows even better wave transmission in the 1-7 GHz range. If the problem of the high-frequency dielectric constant imaginary extremum can be solved, the wave transmission performance of sample FeSiO3@COF will be even better.
[0082] In summary, this invention discloses a method for preparing FeSiO3@COF hollow composite nanospheres. Several conclusions were drawn during the preparation process: First, the introduction of COF improves the material's thinness and lightness. Second, the reaction temperature and time must be carefully controlled during the synthesis of FeSiO3@COF hollow composite nanospheres. Third, argon calcination effectively prevents structural collapse of the hollow material, maintaining its structural integrity. Finally, the electromagnetic parameters of the sample obtained by mixing FeSiO3@COF hollow composite nanospheres with paraffin were tested. In the 1-9 GHz frequency range, the composite dielectric constant and permeability of the Fe2(SiO3)3@COF sample were slightly higher than those of the FeSiO3@COF sample, while in the 1-7 GHz frequency range, the composite dielectric constant and permeability of the FeSiO3@COF sample were lower. By adjusting the Fe... 2+ / Fe 3+ By adjusting the formulation, it is hoped that better low-dielectric composite materials can be synthesized.
[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.
Claims
1. A method for preparing FeSiO3@COF hollow composite nanospheres, characterized in that, The preparation method includes the following steps: (1) Preparation of core-shell silica nanospheres Take 6.4 mL of distilled water, 3.2 mL of ammonia water and 101.2 mL of ethanol at 25℃ and mix them evenly. Disperse 100 mg of polystyrene nanospheres, sonicate for 15 min, stir for 10 min, and slowly add 1.5 mL of tetraethyl orthosilicate and 3 mL of 0.2 M ethanol solution of 3-(trimethoxysilyl)propynaldehyde. Add them dropwise simultaneously and stir at a constant speed for 5.5 hours to obtain a white aldehyde-based silica nanosphere solution. Wash with distilled water and ethanol 2-3 times and dry at 60℃. (2) Preparation of hollow silica nanospheres 200 mg of aldehyde-containing silica nanospheres were dispersed in 50 mL of THF solution, sonicated for 30 min, stirred for 20 min, centrifuged, washed twice with ethanol, and dried at 60 °C to obtain 135 mg of white hollow aldehyde-containing silica nanospheres. (3) Preparation of SiCOF nanospheres 180 mg ETTA and 192.6 mg BPDA were dissolved in 9 mL of 1,4-dioxane, and 100 mg of white hollow aldehyde-based silica nanospheres were uniformly dispersed. The mixture was sonicated for 15 min, stirred, and 0.3 mL of 6 mol / L acetic acid was slowly added dropwise. After the resulting mixture was left to stand at room temperature for 72 hours, it was washed alternately with DMF and 1,4-dioxane to thoroughly remove unreacted raw materials and impurities. The mixture was then vacuum dried at 60 °C for 10 hours to finally obtain pale yellow SiCOF nanospheres. (4) 1.2.4 Preparation of FeSiO3@COF hollow composite nanospheres Take 590 mg of ferrous nitrate hexahydrate and 690 mg of urea, dissolve them in 20 mL of distilled water, then take 100 mg of the above SiCOF nanospheres and disperse them in the mixed solution. Add 17 mL of distilled water, stir evenly, and place in a hydrothermal reactor. Heat at 190℃ for 48 h, cool naturally, remove, wash 2-3 times with distilled water and ethanol, and dry in an oven at 60℃ to obtain FeSiO3@COF hollow composite nanospheres. (5) Crystallization of FeSiO3@COF hollow composite nanospheres FeSiO3@COF hollow composite nanospheres were placed in a tube furnace and calcined at 500℃-600℃ in an argon atmosphere for 2 hours to obtain black crystalline FeSiO3@COF hollow composite nanospheres.
2. The preparation method according to claim 1, characterized in that, In step (1), the ratio of ammonia, ethanol, acrylamide and 3-(trimethoxysilyl)propynaldehyde is 1-5 mL ammonia: 50-150 mL ethanol. Mix them evenly, disperse 100 mg of polystyrene nanospheres, sonicate for 15 min, stir for 10 min, and slowly add 1.5 mL of tetraethyl orthosilicate and 3 mL of 0.2 M 1~2:12~24:6~12.
3. The preparation method according to claim 1, characterized in that, In step (1), the organic solvent is any one of N,N-dimethylformamide, dimethyl sulfoxide, toluene, or chloroform.
4. The preparation method according to claim 1, characterized in that, In step (1), the drying is performed at a temperature of 50~70℃ for 1~2 h; In step (1), the cleaning and filtration process is as follows: repeatedly rinse with deionized water and anhydrous ethanol, dry at 50-70°C for 1-2 h, transfer to methanol solution, oscillate at constant temperature for 1-2 h, and then filter and rinse. In step (1), the drying temperature is 80~90℃.
5. The preparation method according to claim 1, characterized in that, In step (2), the initiator is potassium persulfate, azobisisobutyronitrile (AIBN) or azobisisobutyramidine hydrochloride (AIBA).
6. The preparation method according to claim 1, characterized in that, In step (2), the crosslinking agent is ethylene glycol dimethacrylate (EGDMA) and p-vinylbenzene, and the particle size of the styrene is 260~390 nm.
7. The preparation method according to claim 1, characterized in that, In step (2), the ratio of polystyrene, MOF-NH2 powder, initiator, anhydrous DMSO, styrene (St) and crosslinking agent is 50~100:50~100:27~54:60~100:0.35~1.4:0.1~0.2, mg:mg:mg:mL:mL:mL.
8. The preparation method according to claim 1, characterized in that, In step (3), the eluent is any one or more of THF, DMF, CCl3 or toluene; In step (3), the ultrasonic stirring specifically involves ultrasonic stirring for 1 to 20 minutes followed by stirring for 1 to 4 hours.
9. The FeSiO3@COF composite nanomaterial catalyst prepared by any one of the preparation methods according to claims 1 to 8.
10. The application of the FeSiO3@COF composite nanomaterial catalyst according to claim 9 in the adsorption of dye wastewater.