An MXene-based electromagnetic wave absorbing material and its preparation method

Abstract

This invention discloses an MXene-based electromagnetic wave absorbing material and its preparation method, belonging to the field of composite material preparation technology. The preparation method includes the following steps: S1: etching the MAX phase precursor with LiF and HCl; S2: ultrasonically exfoliating, centrifuging, washing, and freeze-drying the product of S1; S3: hydrothermal reaction using Ni(NO3)2·6H2O, Co(NO3)2·6H2O, Na2MoO4, urea, and NH4F as raw materials; S4: hydrothermally sulfiding the product of S3; S5: mixing and reacting the products of S2 and S3 in a solvent to obtain the final product. This invention features a safe and environmentally friendly preparation process, simple technology, and low cost, possessing broad practicality and promotional value. The resulting MXene-based absorbing material possesses abundant heterogeneous interfaces, achieving synergistic optimization of impedance matching and electromagnetic wave attenuation characteristics, simultaneously obtaining strong electromagnetic wave absorption and a wide effective absorption bandwidth at low matching thickness.

Description

Technical Field

[0001] This invention relates to the field of composite material preparation technology, specifically to an MXene-based electromagnetic wave absorbing material and its preparation method. Background Technology

[0002] The rapid development of wireless communication technology has made the research of high-performance electromagnetic wave absorbing materials a mainstream direction. Electromagnetic wave absorbing materials can effectively dissipate and attenuate incident electromagnetic waves, and are considered an effective strategy for eliminating electromagnetic radiation pollution. However, single-component electromagnetic wave absorbing materials cannot achieve strong minimum reflection loss and wide effective bandwidth due to severe impedance mismatch and narrow electromagnetic wave response range. Improving electromagnetic wave dissipation through rational microstructure design and multi-component compounding has attracted widespread attention. Compared with traditional ferromagnetic absorbing agents, dielectric materials with advantages such as corrosion resistance, light weight, excellent physicochemical properties, and excellent processing performance have attracted researchers' interest.

[0003] MXene, a two-dimensional transition metal carbide / nitride, possesses excellent electrical conductivity, a unique layered structure, abundant surface functional groups, and superior solution processability, attracting widespread attention in the field of electromagnetic wave absorption. However, similar to other layered materials, few-layer MXene nanosheets inevitably aggregate and randomly stack due to van der Waals forces and hydrogen bonding. Furthermore, the extremely high conductivity of MXene leads to severe impedance mismatch, causing incident electromagnetic waves to be directly reflected rather than dissipated and attenuated within the absorber.

[0004] How to solve the problems of weak reflection loss, narrow effective absorption bandwidth and large matching thickness of MXene-based electromagnetic wave absorbing materials caused by severe impedance mismatch due to MXene agglomeration, random stacking and ultra-high conductivity through microstructure design and multi-component optimization is one of the key issues that urgently need to be solved in the field of MXene-based electromagnetic wave absorbing materials. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to provide an MXene-based electromagnetic wave absorbing material and its preparation method, thereby solving the problems of weak reflection loss, narrow effective absorption bandwidth, and large matching thickness of existing electromagnetic wave absorbing materials.

[0006] The technical solution of the present invention to solve the above technical problems is as follows:

[0007] The first objective of this invention is to provide a method for preparing an MXene-based electromagnetic wave absorbing material, comprising the following steps:

[0008] S1: The MAX phase precursor was etched with a mixed solution including LiF and HCl to obtain accordion-shaped MXene;

[0009] S2: The accordion-shaped MXene obtained in S1 was subjected to ultrasonic exfoliation, centrifugal washing and freeze drying to obtain few-layer MXene;

[0010] S3: CoNiMo-LDH powder was prepared by hydrothermal reaction using Ni(NO3)2·6H2O, Co(NO3)2·6H2O, Na2MoO4, urea and NH4F as raw materials;

[0011] S4: The CoNiMo-LDH powder obtained in S3 is subjected to a hydrothermal sulfidation reaction to obtain CoNiMo-LDH sulfide;

[0012] S5: Prepared by mixing and reacting the few-layer MXene obtained in S2 and the CoNiMo-LDH sulfide obtained in S4 in a solvent.

[0013] The beneficial effects of this invention are as follows: This invention utilizes a combination of hydrothermal and freeze-drying methods to prepare high-performance CoNiMoS@MXene electromagnetic wave absorbing materials. The preparation process is safe and environmentally friendly, simple, and low-cost, possessing broad practicality and promotional value. The prepared CoNiMoS@MXene electromagnetic wave absorbing material possesses abundant heterogeneous interfaces, achieving synergistic optimization of impedance matching and electromagnetic wave attenuation characteristics. It simultaneously achieves strong electromagnetic wave absorption and a wide effective absorption bandwidth with a low matching thickness. These advantages give the prepared electromagnetic wave absorbing material broad application prospects and provide new ideas for the design and development of high-performance MXene-based electromagnetic wave absorbing materials.

[0014] Furthermore, the MAX phase precursor in S1 is a Ti3AlC2 precursor.

[0015] Furthermore, S1 includes the following sub-steps:

[0016] S11: Add MAX phase precursor powder to a mixed solution including LiF and HCl, stir, and obtain a MAX phase suspension;

[0017] S12: The MAX phase suspension obtained in S11 was centrifuged and washed to obtain accordion-shaped MXenen.

[0018] Furthermore, the stirring temperature in S11 is 35-40℃, the stirring time is 24-36 h, and the stirring speed is 500-1000 rpm.

[0019] Furthermore, in S12, the centrifugation rate is 3500-5000 rpm for 5-10 min, and the solution is washed with deionized water until the pH of the solution is 6-7.

[0020] Furthermore, S2 includes the following sub-steps:

[0021] S21: Disperse the accordion-shaped MXene obtained in S1 in deionized water and treat it with ultrasound;

[0022] S22: The dispersion obtained after ultrasonic treatment in S21 is centrifuged and washed, and the supernatant is collected to obtain a few-layer MXene dispersion.

[0023] S23: Freeze-dry the few-layer MXene dispersion obtained in S22 to obtain few-layer MXene.

[0024] Furthermore, the ultrasonic treatment in S21 has a power of 360-500 W and a duration of 15-20 min.

[0025] Furthermore, in S22, the centrifugation rate is 3500-5000 rpm, and the time is 5-10 min.

[0026] Furthermore, the freeze-drying time in S23 is 48-72 h.

[0027] Furthermore, S3 includes the following sub-steps:

[0028] S31: Add Ni(NO3)2·6H2O, Co(NO3)2·6H2O, Na2MoO4, urea and NH4F to deionized water, and stir ultrasonically to obtain a reaction solution;

[0029] S32: First, the reaction solution obtained in S31 is subjected to hydrothermal reaction, then centrifuged, washed, and dried to obtain CoNiMo-LDH powder.

[0030] Furthermore, the ultrasonic stirring power in S31 is 360-500 W, and the time is 1-2 h.

[0031] Furthermore, the hydrothermal reaction in S32 is carried out at a temperature of 150-180℃ for 6-8 hours.

[0032] Furthermore, the centrifugation rate in S32 is 3500-5000 rpm; the drying temperature is 80-100℃.

[0033] Furthermore, S4 includes the following sub-steps:

[0034] S41: The CoNiMo-LDH powder obtained in S3 and Na2S·9H2O were ultrasonically stirred in deionized water to obtain a reaction solution;

[0035] S42: First, the reaction solution obtained in S41 is subjected to hydrothermal sulfidation reaction, then centrifuged, washed, and dried to obtain CoNiMo-LDH sulfide.

[0036] Furthermore, the mass ratio of CoNiMo-LDH powder to Na2S·9H2O in S41 is 1.0:(0.2-5.0).

[0037] The hydrothermal sulfidation reaction in S42 takes place at a temperature of 120-150℃ for 10-15 hours.

[0038] The beneficial effects of adopting the above-mentioned further technical solution are as follows: The present invention prepares CoNiMo-LDH sulfide through hydrothermal sulfidation reaction. By adjusting the ratio of CoNiMo-LDH powder and Na2S·9H2O, the degree of sulfidation can be adjusted, thereby realizing the control of the electromagnetic wave absorption performance of the composite material to meet the needs of different applications and has broad application prospects.

[0039] Furthermore, the ultrasonic stirring power in S41 is 360-500 W, and the time is 1-2 h.

[0040] Furthermore, the centrifugation rate in S42 is 6000-8000 rpm for 3-5 min; the drying temperature is 60-80℃ for 8-10 h.

[0041] Furthermore, S5 includes the following sub-steps:

[0042] S51: The few-layer MXene obtained in S2 and the CoNiMo-LDH sulfide obtained in S4 are ultrasonically stirred in deionized water to obtain a reaction solution;

[0043] S52: The reaction solution obtained in S51 is shaken and mixed to carry out the reaction, and then freeze-dried to obtain MXene-based electromagnetic wave absorbing material.

[0044] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: The present invention successfully prepares MXene-based electromagnetic wave absorbing materials with rich heterostructures through electrostatic self-assembly strategy of few-layer MXene and CoNiMo-LDH sulfides. The preparation conditions are mild and the preparation process is safe and environmentally friendly.

[0045] Furthermore, the ultrasonic stirring power in S51 is 360-500 W, and the time is 20-30 min.

[0046] Furthermore, the shaking speed in S52 is 200-500 rpm; the reaction time is 24-36 h; and the temperature is 25-30℃.

[0047] Furthermore, the freeze-drying temperature in S52 is -30~-40℃, and the time is 48-72 h.

[0048] The second objective of this invention is to provide an MXene-based electromagnetic wave absorbing material, prepared using the above-described method.

[0049] The present invention has the following beneficial effects:

[0050] The preparation method of this invention is simple and feasible, with low production cost and easy mass production. By introducing low-conductivity CoNiMo-LDH sulfides into MXene, impedance matching and electromagnetic wave attenuation characteristics are effectively balanced. Simultaneously, the introduction of CoNiMo-LDH sulfides constructs abundant heterogeneous interfaces in the composite material, which can induce polarization loss. This invention, through the synergistic optimization of impedance matching and electromagnetic wave attenuation characteristics and the coupling effect between multiple loss mechanisms (dielectric loss, magnetic loss, and polarization loss), endows the composite material with strong electromagnetic wave absorption and a wide effective absorption bandwidth at a low matching thickness. Attached Figure Description

[0051] Figure 1 This is a scanning electron microscope image of the CoNiMo-LDH powder prepared in Example 1;

[0052] Figure 2 The image shows a scanning electron microscope (SEM) image of the CoNiMo-LDH sulfide prepared in Example 1.

[0053] Figure 3 The image shows a scanning electron microscope (SEM) image of the CoNiMoS@MXene composite material prepared in Example 1.

[0054] Figure 4 XRD patterns of the few (mono)-layer MXene, CoNiMo-LDH powder, CoNiMo-LDH sulfide and CoNiMoS@MXene composite material prepared in Example 1;

[0055] Figure 5 The electromagnetic wave absorption performance of the CoNiMoS@MXene composite material prepared in Example 1 is shown in the figure.

[0056] Figure 6 The electromagnetic wave absorption performance of the CoNiMoS@MXene composite material prepared in Example 2 is shown in the figure.

[0057] Figure 7 The electromagnetic wave absorption performance of the CoNiMoS@MXene composite material prepared in Example 3 is shown in the figure.

[0058] Figure 8 Electromagnetic wave absorption performance of the CoNiMoS@MXene composite material prepared in Comparative Example 1;

[0059] Figure 9 The electromagnetic wave absorption performance of the CoNiMoS@MXene composite material prepared in Comparative Example 2 is shown in the figure. Detailed Implementation

[0060] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples are only used to explain the present invention and are not intended to limit the scope of the present invention. Where specific conditions are not specified in the examples, they are carried out according to conventional conditions or conditions recommended by the manufacturer. Where the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.

[0061] Example 1:

[0062] A method for preparing an MXene-based electromagnetic wave absorbing material includes the following steps:

[0063] S1: Preparation of accordion-shaped MXene

[0064] Accordion-shaped MXene was prepared by etching the Al phase in the Ti3AlC2 precursor using a substitute HF method (LiF-HCl mixed solution); the specific steps are as follows:

[0065] S11: A LiF-HCl mixed solution (LiF concentration 0.05 g / mL, HCl concentration 9 mol / L) was prepared by mixing LiF and HCl. Then, Ti3AlC2 precursor powder (1 g) was slowly added, and the mixture was magnetically stirred at 35℃ for 24 h at a stirring speed of 750 rpm to obtain Ti3C2T. x suspension;

[0066] S12: Ti3C2T obtained from S11 was repeatedly washed by centrifugation with deionized water. x The suspension was centrifuged until the solution pH reached 7, at a speed of 4000 rpm for 8 min to obtain Ti3C2T. x Precipitate (accordion-shaped MXene).

[0067] S2: Preparation of few (mono)layer MXene

[0068] The accordion-shaped MXene was ultrasonically exfoliated, centrifuged, washed, and freeze-dried to obtain a few (mono) layers of MXene; the specific steps are as follows:

[0069] S21: The Ti3C2T obtained in S1 x The precipitate (1 g) was dispersed in deionized water (50 mL) and sonicated for 15 min at a power of 400 W to promote the exfoliation of multilayer MXene.

[0070] S22: The stripped MXene dispersion was centrifuged and washed at a speed of 4000 rpm for 8 min. The supernatant was collected to obtain a few-layer MXene dispersion.

[0071] S23: The few-layer MXene dispersion obtained in S22 was pre-frozen at -28°C and then freeze-dried for 60 h using a freeze dryer to obtain few (single)-layer MXene powder.

[0072] S3: Preparation of CoNiMo-LDH powder

[0073] The preparation is carried out via a hydrothermal method, and the specific steps are as follows:

[0074] S31: Add 1 mmol Ni(NO3)2·6H2O, 1 mmol Co(NO3)2·6H2O, 1 mmol Na2MoO4, 300 mg urea and 74 mg NH4F to deionized water and disperse them evenly under ultrasonic stirring to obtain a reaction solution. The ultrasonic power is 400 W and the time is 1 h.

[0075] S32: Add the reaction solution obtained in S31 to a 100 mL stainless steel autoclave, and then react at 150 °C for 6 h;

[0076] S33: The solution of S32 after reaction and cooling to room temperature was washed repeatedly by centrifugation with deionized water at a speed of 4000 rpm for 8 min, and then dried in an oven at 80℃ to obtain CoNiMo-LDH powder.

[0077] S4: Preparation of CoNiMo-LDH sulfides

[0078] CoNiMo-LDH sulfide was prepared by hydrothermal sulfidation of CoNiMo-LDH powder. The specific steps are as follows:

[0079] S41: Dissolve the CoNiMo-LDH powder (5 mg) obtained in S3 and Na2S·9H2O (1 mg) in 50 mL of deionized water, and under ultrasonic stirring at a power of 400 W for 1 h, a uniformly mixed solution is obtained. The mass ratio of CoNiMo-LDH powder to Na2S·9H2O is 1.0:5.0.

[0080] S42: Add the mixed solution obtained in S41 to a stainless steel autoclave (100 mL) and react at 120℃ for 12 h.

[0081] S43: After the high-pressure reactor is cooled to room temperature, the precipitate is washed repeatedly with deionized water and ethanol alternately. The washing speed is 8000 rpm and the time is 5 min. Then the precipitate is placed in a 60℃ oven to dry for 8 h to obtain CoNiMo-LDH sulfide powder.

[0082] S5: Preparation of MXene-based electromagnetic wave absorbing materials

[0083] The few (mono)-layer MXene obtained from S2 and the CoNiMo-LDH sulfide obtained from S4 were mixed, and under the action of a shaker, a CoNiMoS@MXene electromagnetic wave absorbing material with a heterostructure was obtained through an electrostatic self-assembly strategy and subsequent freeze-drying process. The specific steps are as follows:

[0084] S51: Mix the 10 mg of MXene (single-layer) obtained in S2 and the 10 mg of CoNiMo-LDH sulfide obtained in S4 in a certain proportion, disperse them in 50 mL of deionized water, and sonicate for 20 min at a power of 400 W to ensure that the two are fully mixed and homogeneous to obtain the reaction solution.

[0085] S52: Place the reaction solution obtained in step S51 on a shaker, with a shaking speed of 300 rpm and a temperature of 25°C, and react on the shaker for 30 min;

[0086] S53: The solution obtained after the reaction of S52 was pre-frozen at -26℃ for 45 min, and then freeze-dried at -40℃ for 60 h to obtain MXene-based electromagnetic wave absorbing material (CoNiMoS@MXene composite material).

[0087] Example 2:

[0088] A method for preparing an MXene-based electromagnetic wave absorbing material includes the following steps:

[0089] The preparation method is the same as in Example 1, except that the mass ratio of CoNiMo-LDH powder and Na2S·9H2O in Example 1 is changed to 1.0:1.0, wherein the added mass of CoNiMo-LDH powder is 5 mg and the added mass of Na2S·9H2O is 5 mg, and the remaining steps remain unchanged.

[0090] Example 3:

[0091] A method for preparing an MXene-based electromagnetic wave absorbing material includes the following steps:

[0092] The preparation method is the same as in Example 1, except that the mass ratio of CoNiMo-LDH powder and Na2S·9H2O in Example 1 is changed to 1.0:5.0, wherein the added mass of CoNiMo-LDH powder is 5 mg and the added mass of Na2S·9H2O is 25 mg, and the remaining steps remain unchanged.

[0093] Comparative Example 1:

[0094] A method for preparing an MXene-based electromagnetic wave absorbing material includes the following steps:

[0095] The preparation method is the same as in Example 1, except that the mass ratio of CoNiMo-LDH powder and Na2S·9H2O in Example 1 is changed to 1.0:0.1, wherein the added mass of CoNiMo-LDH powder is 5 mg and the added mass of Na2S·9H2O is 0.5 mg, and the remaining steps remain unchanged.

[0096] Comparative Example 2:

[0097] A method for preparing an MXene-based electromagnetic wave absorbing material includes the following steps:

[0098] The preparation method is the same as in Example 1, except that the mass ratio of CoNiMo-LDH powder and Na2S·9H2O in Example 1 is changed to 1.0:8.0, wherein the added mass of CoNiMo-LDH powder is 5 mg and the added mass of Na2S·9H2O is 40 mg, and the remaining steps remain unchanged.

[0099] Experimental Example 1: Microscopic Morphology Characterization

[0100] Using the CoNiMo-LDH powder, CoNiMo-LDH sulfide powder, and CoNiMoS@MXene composite material prepared in Example 1 as test samples, their microstructure was characterized by scanning electron microscopy. The characterization results are as follows: Figures 1-3 As shown.

[0101] from Figure 1 It can be seen that CoNiMo-LDH exhibits a nanoflower-like structure formed by stacked two-dimensional nanosheets, possessing abundant heterostructures that facilitate multiple reflections and scattering of electromagnetic waves, as well as the generation of induced polarization losses, thereby enhancing electromagnetic wave absorption. Figure 2 It can be seen that the microstructure of CoNiMo-LDH sulfide is almost unchanged compared to CoNiMo-LDH, still exhibiting a nanoflower-like structure formed by stacked two-dimensional nanosheets, possessing abundant heterogeneous interfaces, which is beneficial for multiple reflections and scattering of electromagnetic waves and the generation of induced polarization loss, thus improving electromagnetic wave absorption. From Figure 3 It can be seen that the nano-sized CoNiMo-LDH sulfide loaded on the MXene surface constructs numerous heterogeneous interfaces, which can induce polarization loss. At the same time, the introduction of low-conductivity CoNiMo-LDH sulfide can significantly reduce the conductivity of MXene, effectively improve impedance matching, and allow electromagnetic waves to enter the interior of the composite material for dissipation and attenuation.

[0102] Experimental Example 2: XRD Characterization

[0103] X-ray diffraction experiments were conducted on the few-layer (monolayer) MXene (MXene), CoNiMo-LDH powder (MOF), CoNiMo-LDH sulfide powder (LDH-3), and CoNiMoS@MXene composite material (MNCM3-20) prepared in Example 1. The characterization results are as follows: Figure 4 As shown.

[0104] from Figure 4 It can be seen that the characteristic peaks of few (mono)-layer MXene, CoNiMo-LDH and CoNiMo-LDH sulfides indicate their successful preparation. The simultaneous detection of characteristic peaks of MXene and CoNiMo-LDH sulfides in the CoNiMoS@MXene composite material also indicates the successful composite material.

[0105] Experimental Example 3:

[0106] The electromagnetic wave absorption properties of the CoNiMoS@MXene composite materials prepared in Examples 1-3 and Comparative Examples 1-2 were measured, and their electromagnetic wave absorption properties at different matching thicknesses were determined. The experimental results are as follows: Figure 5-Figure 9 As shown in Table 1.

[0107] Table 1 Electromagnetic wave absorption performance of different samples

[0108]

[0109] like Figure 5-Figure 9 As shown, the electromagnetic wave absorption performance of the prepared composite materials at different matching thicknesses shows that, with the increase of matching thickness, the peak value of the minimum reflection loss shifts to lower frequencies, satisfying the quarter-wavelength theory. Specifically, the composite materials prepared in Examples 1-3 all exhibit low reflection losses (-21.29 dB, -56.4 dB, and -23.31 dB, respectively) and wide effective absorption bandwidths (4.84 GHz, 8.1 GHz, and 3.53 GHz, respectively) at the optimal matching thickness, which are sufficient for practical applications. The prepared composite materials show a trend of first strengthening and then weakening with increasing CoNiMo-LDH sulfurization degree. The sample prepared in Example 2 exhibits significantly better electromagnetic wave absorption performance compared to the other examples, giving it a competitive advantage in practical applications and providing new ideas for the design and development of high-performance MXene-based electromagnetic wave absorbing materials. Comparative Examples 1 and 2, on the other hand, were samples with excessively low or high levels of sulfurization, respectively. Their minimum reflection loss was significantly higher than that of Examples 1-3, at -4.88 dB and -5.59 dB, respectively, which could not meet the requirements of practical applications.

[0110] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing an MXene-based electromagnetic wave absorbing material, characterized in that, Includes the following steps: S1: The MAX phase precursor was etched with a mixed solution including LiF and HCl to obtain accordion-shaped MXene; S2: The accordion-shaped MXene obtained in S1 was subjected to ultrasonic exfoliation, centrifugal washing and freeze drying to obtain few-layer MXene; S3: CoNiMo-LDH powder was prepared by hydrothermal reaction using Ni(NO3)2·6H2O, Co(NO3)2·6H2O, Na2MoO4, urea and NH4F as raw materials; S4: The CoNiMo-LDH powder obtained in S3 is subjected to a hydrothermal sulfidation reaction to obtain CoNiMo-LDH sulfide; S5: Prepared by mixing and reacting the few-layer MXene obtained in S2 and the CoNiMo-LDH sulfide obtained in S4 in a solvent; S4 includes the following sub-steps: S41: The CoNiMo-LDH powder obtained in S3 and Na2S·9H2O were ultrasonically stirred in deionized water to obtain a reaction solution; S42: First, the reaction solution obtained from S41 is subjected to hydrothermal sulfidation reaction, then centrifuged, washed, and dried to obtain CoNiMo-LDH sulfide. The mass ratio of CoNiMo-LDH powder to Na2S·9H2O in S41 is 1.0:(0.2-5.0). The hydrothermal sulfidation reaction in S42 is carried out at a temperature of 120-150℃ for 10-15 hours.

2. The method for preparing the MXene-based electromagnetic wave absorbing material according to claim 1, characterized in that, S1 includes the following steps: S11: Add MAX phase precursor powder to a mixed solution including LiF and HCl, stir, and obtain a MAX phase suspension; S12: The MAX phase suspension obtained in S11 was centrifuged and washed to obtain accordion-shaped MXene.

3. The method for preparing the MXene-based electromagnetic wave absorbing material according to claim 1, characterized in that, S2 includes the following steps: S21: Disperse the accordion-shaped MXene obtained in S1 in deionized water and treat it with ultrasound; S22: The dispersion obtained after ultrasonic treatment in S21 is centrifuged and washed, and the supernatant is collected to obtain a few-layer MXene dispersion. S23: Freeze-dry the few-layer MXene dispersion obtained in S22 to obtain few-layer MXene.

4. The method for preparing the MXene-based electromagnetic wave absorbing material according to claim 1, characterized in that, S3 includes the following steps: S31: Add Ni(NO3)2·6H2O, Co(NO3)2·6H2O, Na2MoO4, urea and NH4F to deionized water, and stir ultrasonically to obtain a reaction solution; S32: First, the reaction solution obtained in S31 is subjected to hydrothermal reaction, then centrifuged, washed, and dried to obtain CoNiMo-LDH powder.

5. The method for preparing the MXene-based electromagnetic wave absorbing material according to claim 4, characterized in that, The hydrothermal reaction in S32 is carried out at a temperature of 150-180℃ for 6-8 hours.

6. The method for preparing the MXene-based electromagnetic wave absorbing material according to claim 1, characterized in that, S5 includes the following steps: S51: The few-layer MXene obtained in S2 and the CoNiMo-LDH sulfide obtained in S4 are ultrasonically stirred in deionized water to obtain a reaction solution; S52: The reaction solution obtained in S51 is shaken and mixed to carry out the reaction, and then freeze-dried to obtain MXene-based electromagnetic wave absorbing material.

7. The method for preparing the MXene-based electromagnetic wave absorbing material according to claim 6, characterized in that, The shaking speed in S52 is 200-500 rpm; the reaction time is 24-36 h; and the temperature is 25-30℃.

8. An MXene-based electromagnetic wave absorbing material, characterized in that, It is prepared by the preparation method according to any one of claims 1-7.

Images