Preparation method of MXene / PSB / Fe3O4 composite aerogel

Abstract

The invention discloses a preparation method of MXene / PSB / Fe3O4 composite aerogel, and relates to a preparation method of green and energy-saving multifunctional composite aerogel. The invention aims to solve the technical problems of single energy loss mode, narrow electromagnetic wave absorption bandwidth and single function of the existing electromagnetic wave absorption material. According to the invention, poly-Schiff base is used as an aerogel matrix, MXene is used as a dielectric gene, Fe3O4 is used as a magnetic loss material to improve impedance matching, and the composite aerogel with a microscopic ordered structure is prepared through a carbonyl ammonia condensation reaction. The aerogel not only has excellent electromagnetic wave absorption performance, but also has various functions such as excellent radar stealth performance, heat insulation performance and flame retardant performance. Through the metamaterial design, the effective absorption bandwidth can reach 36.1 GHz, and a foundation is laid for practical application of the metamaterial.

Description

Technical Field

[0001] The present invention relates to a preparation method of a green energy-saving multifunctional composite aerogel. Background Art

[0002] With the rapid development of information technology, the wide application of electronic devices such as mobile communication and satellite communication has brought great convenience to human life. However, while technology has changed life, it has also brought serious electromagnetic wave pollution, causing potential harm to aspects such as the environment, human health, and the normal operation of precision instruments. Electromagnetic wave pollution has become the fourth major pollution after noise, air, and water pollution. Electromagnetic wave absorbing materials can effectively reduce electromagnetic wave pollution. Therefore, the design and manufacture of new high-performance electromagnetic wave absorbing materials have become the focus of contemporary society.

[0003] For the Chinese patent "A honeycomb-shaped MXene material and its preparation method and application" (Publication No.: CN116375491A), first, the MXene dispersion liquid and the polystyrene microsphere dispersion liquid are each ultrasonically treated and then mixed. After drying, it is calcined to obtain a honeycomb-shaped MXene powder material. However, the material prepared by this method has a small minimum reflection loss value due to few components and a single loss mechanism, and its application in complex environments may be limited. For the Chinese patent "A Fe 3 O 4 @C magnetic modified MXene-based aerogel microwave absorption material and its preparation method" (Publication No.: CN118874349A), first, a nanosized shuttle-shaped Fe 2 O 3 precursor is synthesized by a hydrothermal reaction, and then Fe 2 O 3 @PDA is obtained by using dopamine hydrochloride in a tris(hydroxymethyl)aminomethane aqueous solution, and annealing treatment gives Fe 3 O 4 @C particles. Using gelatin as a colloid, poly(diallyldimethylammonium chloride) modifies Fe 3 O 4 @C particles, which are compounded with monolayer MXene nanosheets, and after freeze-drying, Fe 3 O 4 @C magnetic modified MXene-based aerogel is obtained. The monolayer MXene nanosheets used in this method are prone to self-accumulation and aggregation during the assembly process, resulting in impedance mismatch and affecting its wave absorption performance.

[0004] As a new type of two-dimensional nanomaterial, MXene has the advantages of a unique layered structure, a high specific surface area, metal-like conductivity, and abundant active centers. However, when MXene is exposed to water and oxygen, it is prone to affecting the structural stability, resulting in the deterioration of its inherent properties. Schiff base contains a C=N bond, and the lone pair electrons of N enable it to introduce various functional groups. However, due to the solvent effect, Schiff base aerogels are prone to volume shrinkage. In the present invention, poly-Schiff base aerogels are in-situ grown on the surface of MXene, which not only effectively inhibits the oxidation and self-aggregation defects of MXene, but also solves the problems of volume shrinkage and collapse of Schiff base aerogels. Summary of the Invention

[0005] The present invention aims to solve the technical problems of existing electromagnetic wave absorbing materials, such as a single way of dissipating energy, a narrow electromagnetic wave absorption bandwidth, and a single functionality, and provides a preparation method for an MXene / PSB / Fe 3 O 4 composite aerogel.

[0006] The preparation method of the MXene / PSB / Fe 3 O 4 composite aerogel of the present invention is carried out according to the following steps:

[0007] 1. Mix MXene nanosheets with deionized water, then add ethylenediamine, and stir for 6 h to 7 h under an inert atmosphere and at a temperature of 95 °C to 100 °C to obtain an aminated MXene dispersion solution;

[0008] The mass ratio of the MXene nanosheets to the volume of ethylenediamine is (0.05 g to 0.2 g): 200 μL;

[0009] 2. Mix a glutaraldehyde solution with absolute ethanol to obtain a glutaraldehyde ethanol solution, and then add the aminated MXene dispersion solution obtained in step 1 and stir to obtain a mixed solution;

[0010] The concentration of the glutaraldehyde solution is 50 wt%;

[0011] The volume ratio of the glutaraldehyde solution to absolute ethanol is (600 μL to 800 μL): (9 mL to 11 mL);

[0012] The volume ratio of the glutaraldehyde ethanol solution in step 2 to the MXene-ethylenediamine aqueous solution in step 1 is 1: (0.9 to 1.1);

[0013] 3. Mix FeCl 3 ·6H 2 O with FeSO 4 ·7H 2O is added to the mixed solution obtained in Step 2 and stirred to obtain a mixed solution;

[0014] The described FeCl 3 ·6H 2 O and FeSO 4 ·7H 2 O have a molar ratio of 2:(0.8 - 1.2);

[0015] The described FeCl 3 ·6H 2 O and the mass ratio of MXene nanosheets in Step 1 is 1:(0.2 - 0.9);

[0016] IV. Add the NaOH solution to the mixed solution obtained in Step 3 to adjust the pH to 9 - 12, then stir at 85°C - 90°C for 3h - 3.5h, and then obtain MXene / PSB / Fe 3 O 4 composite aerogel (MPF - D).

[0017] In the present invention, poly - Schiff base aerogel is in - situ grown on the surface of MXene by water - bath heating. By utilizing the advantages of the composition and structure of both, it not only effectively improves the self - aggregation tendency and antioxidant ability of MXene nanosheets, but also enhances the stability of the porous structure of the aerogel; at the same time, the Fe 3 O 4 nanoparticles are uniformly embedded in the pore framework of the aerogel by chemical precipitation method, and finally, through directional freeze - drying, MXene / PSB / Fe 3 O 4 electromagnetic wave absorption material is obtained, providing a new idea for solving the problem of electromagnetic wave pollution.

[0018] In the present invention, poly - Schiff base (PSB) is used as the aerogel matrix, MXene is used as the dielectric gene to improve the electrical conductivity, and Fe 3 O 4 is used as the magnetic loss material to improve the magnetic loss and impedance matching. Through the carbonyl - amine condensation reaction, a directional MXene / PSB / Fe 3 O 4 composite aerogel with a microstructure is prepared. It not only has radar stealth, heat insulation and flame - retardant properties, but also has excellent electromagnetic wave absorption properties. When the thickness is 2.09 mm, the minimum reflection loss (RL min ) is as high as - 79.16 dB; when the thickness is 1.36 mm, the maximum effective absorption bandwidth (EAB max ) is as high as 4.40 GHz, providing new inspiration for the preparation of multifunctional electromagnetic wave absorption materials.

[0019] Compared with the prior art, the advantages of the present invention are as follows:

[0020] (1) By means of a surface functionalization strategy, amino groups are grafted onto the surface of MXene nanosheets, effectively expanding the layer spacing and changing the inherent self-aggregation tendency of MXene nanosheets; by changing the concentration of MXene, the dielectric gene is adjusted, the electronic configuration is changed, and the conductive performance is optimized. At the same time, the large specific surface area of MXene is conducive to the in-situ polymerization of amino groups on MXene and glutaraldehyde (GA) into aerogels on the surface-functionalized MXene nanosheets; further, Fe 3 O 4 nanoparticles are uniformly embedded in the pores of the aerogel to enhance the magnetic loss ability, thereby realizing the synergistic enhancement effect of electromagnetic loss and improving the impedance matching; through the directional freeze-drying process, the ordered porous structure of the material aerogel improves the multiple reflection and scattering of electromagnetic waves, thereby further improving the electromagnetic loss. Therefore, the present invention can achieve excellent microwave absorption performance without calcination, avoiding additional energy consumption, and this green and environmentally friendly synthesis scheme facilitates the popularization and application of this material;

[0021] (2) The present invention adjusts the pore geometry structure of MXene / PSB / Fe 3 O 4 aerogel by means of directional freeze-drying. The directional and ordered microstructure is conducive to increasing the transmission path and multi-polarization response of electromagnetic waves, promoting the attenuation of electromagnetic waves, and the internal micro-capacitor structure promotes the electromagnetic response, optimizes the impedance matching, and improves the microwave absorption performance;

[0022] (3) When the thickness of the MXene / PSB / Fe 3 O 4 composite aerogel prepared by the present invention is 2.09 mm, the minimum reflection loss (RL min ) is as high as -79.16 dB; when the thickness is 1.36 mm, the maximum effective absorption bandwidth (EAB max ) is as high as 4.40 GHz. The MXene / PSB / Fe 3 O 4 composite aerogel prepared by the present invention is an electromagnetic wave absorption material with thin thickness, strong absorption and wide microwave absorption frequency band; the carbonyl-amine condensation reaction used to prepare PSB in the present invention is an environmentally friendly synthesis method;

[0023] (4) The multifunctionality of the material not only overcomes the limitation of single application scenario, but also indicates the future development direction of materials. The maximum reduction value of the radar stealth performance of the MXene / PSB / Fe 3 O 4 composite aerogel prepared by the present invention is 30.04 dBm at 0° angle 2, and has excellent heat insulation and flame retardant properties. Through the truncated pyramid metamaterial design, the effective absorption bandwidth can reach 36.1 GHz. Therefore, the MXene / PSB / Fe 3 O 4 composite aerogel is expected to develop into an ultimate functional material integrating electromagnetic wave absorption, heat insulation, flame retardancy and radar stealth performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Powder X-ray diffraction pattern of the MXene / PSB / Fe 3 O 4 aerogel prepared in Experiment 1;

[0025] Figure 2 FT-IR spectra of pure MXene, MXene-NH 2 and MPF-D aerogel in Step 1 of Experiment 1;

[0026] Figure 3 High-resolution TEM image of the MXene / PSB / Fe 3 O 4 aerogel prepared in Experiment 1;

[0027] Figure 4 3D RL diagrams of the oriented MXene / PSB / Fe 3 O 4 and non-oriented MXene / PSB / Fe 3 O 4 aerogels prepared in Experiment 1 and Experiment 2;

[0028] Figure 5 Effective wave absorption bandwidth diagrams of the oriented MXene / PSB / Fe 3 O 4 and non-oriented MXene / PSB / Fe 3 O 4 aerogels prepared in Experiment 1 and Experiment 2;

[0029] Figure 6 Gradient structure design diagram of MPF-D aerogel in Step 2 of Experiment 3;

[0030] Figure 7 3D RCS (a) and 2D RCS (b) diagrams of the MXene / PSB / Fe 3 O 4 aerogel prepared in Experiment 1;

[0031] Figure 8 3D RCS (a) and 2D RCS (b) diagrams of the MXene / PSB / Fe 3 O 4Photos of the thermal insulation and flame retardancy tests of the aerogel. Detailed implementation manners

[0032] Detailed implementation manner 1: This implementation manner is a preparation method of a MXene / PSB / Fe 3 O 4 composite aerogel, and specifically, it is carried out according to the following steps:

[0033] 1. Mix MXene nanosheets with deionized water, then add ethylenediamine, and stir for 6 h to 7 h under an inert atmosphere and at a temperature of 95 °C to 100 °C to obtain an aminated MXene dispersion solution;

[0034] The mass ratio of the MXene nanosheets to the volume of ethylenediamine is (0.05 g to 0.2 g): 200 μL;

[0035] 2. Mix the glutaraldehyde solution with absolute ethanol to obtain a glutaraldehyde ethanol solution, then add the aminated MXene dispersion solution obtained in step 1 and stir to obtain a mixed solution;

[0036] The concentration of the glutaraldehyde solution is 50 wt%;

[0037] The volume ratio of the glutaraldehyde solution to absolute ethanol is (600 μL to 800 μL): (9 mL to 11 mL);

[0038] 3. Add FeCl 3 ·6H 2 O and FeSO 4 ·7H 2 O together into the mixed solution obtained in step 2 and stir to obtain a mixed solution;

[0039] The molar ratio of FeCl 3 ·6H 2 O to FeSO 4 ·7H 2 O is 2: (0.8 to 1.2);

[0040] The mass ratio of FeCl 3 ·6H 2 O to the MXene nanosheets in step 1 is 1: (0.2 to 0.9);

[0041] 4. Add the NaOH solution to the mixed solution obtained in step 3 to adjust the pH to 9 to 12, then stir at 85 °C to 90 °C for 3 h to 3.5 h, and then obtain the MXene / PSB / Fe 3 O 4 composite aerogel (MPF-D) after directional freeze-drying.

[0042] Specific Embodiment 2: The difference between this embodiment and Specific Embodiment 1 is that: the preparation method of the MXene nanosheets in Step 1 is as follows: Dissolve 2 g of LiF powder in 40 mL of 9 mol / L HCl solution, stir at 40 °C for 20 min to obtain a clear solution; slowly add 2 g of Ti 3 AlC 2 to the above solution, stir at 45 °C for 48 h to obtain a Ti 3 C 2 T x dispersion; then repeatedly centrifuge and wash the dispersion with deionized water, the centrifuge speed is 3500 rpm, each centrifugation is 5 min, centrifuge and wash multiple times until the pH is 6 - 7, then remove the supernatant, add deionized water to redisperse the precipitate, ultrasonicate for 1 h, then centrifuge at 3500 rpm for 1 h, and freeze-dry to obtain the MXene nanosheets. Others are the same as Specific Embodiment 1.

[0043] Specific Embodiment 3: The difference between this embodiment and Specific Embodiment 1 or 2 is that: the inert atmosphere in Step 1 is nitrogen; the mass ratio of the MXene nanosheets to the volume of deionized water in Step 1 is (0.005 g - 0.02 g):1 mL. Others are the same as Specific Embodiment 1 or 2.

[0044] Specific Embodiment 4: The difference between this embodiment and one of Specific Embodiments 1 to 3 is that: the volume ratio of the glutaraldehyde ethanol solution in Step 2 to the MXene-ethylenediamine aqueous solution in Step 1 is 1:(0.9 - 1.1). Others are the same as one of Specific Embodiments 1 to 3.

[0045] Specific Embodiment 5: The difference between this embodiment and Specific Embodiment 4 is that: the stirring in Step 2 is carried out at room temperature. Others are the same as Specific Embodiment 4.

[0046] Specific Embodiment 6: The difference between this embodiment and Specific Embodiment 5 is that: the concentration of the NaOH solution in Step 4 is 1 mol / L. Others are the same as Specific Embodiment 5.

[0047] Specific Embodiment 7: The difference between this embodiment and Specific Embodiment 6 is that: the temperature of the freeze-drying in Step 4 is lower than -62 °C. Others are the same as Specific Embodiment 6.

[0048] The present invention is verified by the following tests:

[0049] Test 1: This test is a preparation method of a MXene / PSB / Fe 3 O 4 composite aerogel, which is specifically carried out according to the following steps:

[0050] 1. Mix 0.15 g of MXene nanosheets with 10 mL of deionized water, then add 200 μL of ethylenediamine, and stir well to make it evenly dispersed. Stir for 6 h under nitrogen protection at a temperature of 95 °C to obtain an aminated MXene (MXene-NH 2 ) dispersion solution;

[0051] The preparation method of the MXene nanosheets is as follows: Dissolve 2 g of LiF powder in a polytetrafluoroethylene container containing 40 mL of 9 mol / L HCl solution, stir at 40 °C for 20 min to obtain a clear and uniform solution; Slowly add 2 g of Ti 3 AlC 2 to the above solution within 5 min, stir at 45 °C for 48 h to obtain a Ti 3 C 2 T x dispersion; Subsequently, repeatedly centrifuge and wash the dispersion with deionized water, the centrifuge speed is 3500 rpm, each centrifugation is 5 min, centrifuge and wash multiple times until the pH is 6 - 7, then remove the supernatant, add deionized water to redisperse the precipitate, then ultrasonicate for 1 h, then centrifuge at a speed of 3500 rpm for 1 h, and freeze-dry to obtain MXene nanosheets;

[0052] 2. Mix 800 μL of glutaraldehyde with 10 mL of absolute ethanol, then add the aminated MXene dispersion solution obtained in step 1, and stir at room temperature for 30 min to obtain a mixed solution;

[0053] 3. Add 0.233 g of FeCl 3 ·6H 2 O and 0.196 g of FeSO 4 ·7H 2 O together to the mixed solution obtained in step 2, and stir for 10 min to obtain a mixed solution;

[0054] 4. Add 1 mol / L NaOH solution to the mixed solution obtained in step 3 to adjust the pH to 12, then stir at 85 °C for 3 h, and then obtain MXene / PSB / Fe 3 O 4 composite aerogel after directional freeze-drying. Denote it as MPF-D, the temperature of directional freeze-drying is -62 °C, and the time is 72 h.

[0055] Experiment 2: The difference between this experiment and Experiment 1 is that the directional freeze-drying described in step 4 is changed to non-directional freeze-drying, and the obtained composite aerogel is denoted as MPF-U. Others are the same as Experiment 1.

[0056] Experiment 3: Step 1. Immerse the composite aerogels prepared in Experiment 1 and Experiment 2 in molten paraffin (the mass ratio of the composite aerogel to paraffin is 1:1) to form a ring shape. In this configuration, the aerogel accounts for 50 wt% of the total mass of the ring. Subsequently, use a vector network analyzer to measure the electromagnetic parameters of the composite aerogel, and calculate the reflection loss of the material to electromagnetic waves according to the transmission line theory through the following equation.

[0057]

[0058] Step 2. Construct a metamaterial structure with the composite aerogel as the substrate: Import the electromagnetic parameters of the composite aerogel measured by the vector network analyzer in Step 1 into the CST electromagnetic field simulation software, and set the frequency range to 2 - 18 GHz. The top of a single piece of the composite aerogel is designed as a periodic array layer, and the bottom layer is constructed as a cube with a side length of 2 mm. The top layer is composed of a pyramid with a height of 5 mm ( Figure 7 the right figure in a) and a truncated pyramid with a height of 2.5 mm ( Figure 7 the left figure in a).

[0059] Step 3: Use the CST electromagnetic field simulation software to simulate the radar stealth performance of the composite aerogel, and calculate the reduction value of the radar cross section (RCS) through the following formula. Use this formula to calculate the RCS values of the PEC plate and the material respectively, and then subtract the two to obtain the reduction value.

[0060]

[0061] Figure 1 The powder X-ray diffraction pattern of the MPF-D aerogel prepared in Experiment 1. It can be seen from the figure that there is a significant and high-intensity diffraction peak at 6.4°, which can be attributed to the (002) crystal plane of MXene. The diffraction peaks at 18.26°, 30.09°, 35.42°, 43.05°, 56.94° and 65.74° correspond to the (111), (220), (311), (400), (511) and (531) crystal planes of Fe 3 O 4 respectively, which proves the successful preparation of Fe 3 O 4 nanoparticles.

[0062] Figure 2 The FT-IR spectra of the MXene nanosheets in Step 1 of Experiment 1, MXene-NH 2 prepared in Step 1 and the finally prepared MPF-D aerogel. Compared with the pure MXene nanosheets, MXene-NH 2The peak of the C-N bond appears in the FT-IR spectrum, indicating that the amino group is successfully grafted. After adding glutaraldehyde for reaction, the appearance of the C=N bond in the FT-IR spectrum of MPF-D indicates the successful preparation of the Schiff base.

[0063] Figure 3 The high-resolution TEM image of the MPF-D aerogel prepared in Experiment 1 shows that spherical PSB and Fe 3 O 4 nanoparticles are uniformly distributed on the multi-layer MXene nanosheets.

[0064] Figure 4 The 3D reflection loss (RL) diagrams of MPF-D (oriented) and MPF-U (non-oriented) aerogels prepared in Experiment 1 and Experiment 2 are shown. Figure a corresponds to MPF-D (oriented), and Figure b corresponds to MPF-U (non-oriented). It can be seen that at a mass filling ratio of 50 wt%, for MPF-D, at a thickness of 2.09 mm, the RL min reaches -79.16 dB. For MPF-U, at a thickness of 1.50 mm, the RL min is only -20.81 dB. Thus, MPF-D exhibits stronger electromagnetic wave attenuation performance.

[0065] Figure 5 The effective absorption bandwidth diagrams of MPF-D (oriented) and MPF-U (non-oriented) aerogels prepared in Experiment 1 and Experiment 2 are shown. Figure a corresponds to MPF-D (oriented), and Figure b corresponds to MPF-U (non-oriented). At a thickness of 1.36 mm, MPF-D obtains an effective absorption bandwidth of 4.40 GHz. The effective absorption bandwidth of MPF-U is 2.64 GHz at a thickness of 1.60 mm. This is attributed to the fact that through the directional freeze-drying process, MPF-D obtains better impedance matching and wave absorption performance than MPF-U.

[0066] Figure 6 The gradient structure design diagram of the MPF-D aerogel in Step 2 of Experiment 3 is shown. The left figure in Figure a corresponds to a truncated pyramid with a height of 2.5 mm at the top layer, and the right figure in Figure a corresponds to a pyramid with a height of 5 mm at the top layer. Both periodic structures exhibit excellent electromagnetic wave (EMWs) absorption performance. The truncated pyramid periodic structure has a wider effective absorption bandwidth, up to 36.1 GHz (Figure b); while the pyramid periodic structure has a stronger RL min value, up to -74.2 dB (Figure c).

[0067] Figure 7 The 3D RCS (Figure a) and 2D RCS (Figure b) diagrams of the MPF-D aerogel prepared in Experiment 1 are shown. It can be seen that its maximum RCS value is 30.04 dB·m 2, indicating that the MPF-D aerogel has excellent radar stealth performance.

[0068] Figure 8 Figure for the heat insulation and flame retardancy test of the MPF-D aerogel prepared in Experiment 1. The MPF-D composite aerogel material prepared in Experiment 1 was placed on a heating plate at 160 °C and heated for 60 min, and its surface temperature only reached 51.9 °C; the MPF-D composite aerogel was placed on an asbestos net, and a layer of petals was covered on it, and a control experiment was carried out with the single petals (that is, without aerogel, only petals). The asbestos net was heated on an alcohol lamp. The single petals began to wither within 30 s and were almost completely carbonized within 120 s (see Figure 8 the first row of photos in). In contrast, after burning for 120 s, the petals distributed on the aerogel were hardly damaged (see Figure 8 the second row of photos in). These two experiments both showed that the MPF-D composite aerogel prepared in Experiment 1 has good heat insulation performance, making it a strong competitor for thermal insulation materials. The MPF-D composite aerogel prepared in Experiment 1 was directly placed in the flame of an alcohol lamp for 60 s, and the morphology of the material remained unchanged, proving its excellent flame retardancy (see Figure 8 the third row of photos in).

[0069] Although the present invention is disclosed above in preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be defined by the claims.

Claims

1. A method for preparing a MXene / PSB / Fe3O4 composite aerogel, characterized in that The preparation method of MXene / PSB / Fe3O4 composite aerogel is carried out according to the following steps:

1. Mix MXene nanosheets with deionized water, add ethylenediamine, and stir for 6 h to 7 h at 95 ° C to 100 ° C in an inert atmosphere to obtain an aminated MXene dispersion solution; The mass ratio of the MXene nanosheets to the volume of ethylenediamine is (0.05 g to 0.2 g): 200 μL; 2. Mixing the glutaraldehyde solution with anhydrous ethanol to obtain a glutaraldehyde ethanol solution, and then adding the aminated MXene dispersion solution obtained in step 1 and stirring to obtain a mixed solution; The concentration of the glutaraldehyde solution is 50wt%; The volume ratio of the glutaraldehyde solution to anhydrous ethanol is (600 μL-800 μL):(9 mL-11 mL); 3. Add FeCl3·6H2O and FeSO4·7H2O to the mixed solution obtained in step 2, and stir to obtain a mixed solution; The molar ratio of FeCl3·6H2O to FeSO4·7H2O is 2:(0.8-1.2); The mass ratio of the FeCl3·6H2O to the MXene nanosheets in step 1 is 1:(0.2-0.9); 4. Add NaOH solution to the mixed solution obtained in step 3 to adjust the pH to 9-12, then stir at 85°C-90°C for 3h-3.5h, and then obtain MXene / PSB / Fe3O4 composite aerogel after directional freeze-drying.

2. The method for preparing a MXene / PSB / Fe3O4 composite aerogel according to claim 1, characterized in that The preparation method of the MXene nanosheets described in step 1 is as follows: 2 g of LiF powder is dissolved in 40 mL of 9 mol / L HCl solution, stirred at 40 ° C for 20 min to obtain a clear solution; 2 g of Ti3AlC2 is slowly added to the above solution, stirred at 45 ° C for 48 h, and Ti3C2T x dispersion; the dispersion was then repeatedly washed by centrifugation with deionized water at a speed of 3500 rpm for 5 minutes each time, and the dispersion was washed by centrifugation multiple times until the pH value was 6-7, and then the supernatant was removed, and deionized water was added to re-disperse the precipitate, and then ultrasonicated for 1 hour, and then centrifuged at a speed of 3500 rpm for 1 hour, and freeze-dried to obtain MXene nanosheets.

3. The method for preparing a MXene / PSB / Fe3O4 composite aerogel according to claim 1, characterized in that The inert atmosphere described in step one is nitrogen; the mass ratio of the MXene nanosheets described in step one to the volume ratio of deionized water is (0.005g~0.02g):1mL.

4. The method for preparing a MXene / PSB / Fe3O4 composite aerogel according to claim 1, characterized in that The volume ratio of the glutaraldehyde ethanol solution in step 2 to the MXene-ethylenediamine aqueous solution in step 1 is 1:(0.9-1.1).

5. The method for preparing a MXene / PSB / Fe3O4 composite aerogel according to claim 1, characterized in that The stirring in step 2 is carried out at room temperature.

6. The method for preparing a MXene / PSB / Fe3O4 composite aerogel according to claim 1, characterized in that The concentration of the NaOH solution described in step 4 is 1 mol / L.

7. The method for preparing a MXene / PSB / Fe3O4 composite aerogel according to claim 1, characterized in that The freeze drying temperature in step 4 is below -62°C.

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