A wave-absorbing material MXene@MnO2 and a preparation method thereof

Abstract

This invention belongs to the field of electromagnetic wave absorbing materials technology, and relates to an absorbing material MXene@MnO2 and its preparation method, including: Step S1: Adding MAX to a hydrofluoric acid solution for etching to generate multilayer MXene; Step S2: Adding the multilayer MXene generated in Step S1 to a potassium permanganate solution and mixing it with a hydrochloric acid solution, and then subjecting the mixed solution to a hydrothermal reaction; Step S3: Drying the product obtained in Step S2 under vacuum to obtain MXene@MnO2; The invented MXene-based composite material and its preparation method have widely available raw materials, are environmentally friendly, have strong sustainability, and can achieve large-scale production. By introducing interfacial polarization caused by the difference in conductivity between MnO2 and TiO2 generated by its own hydrothermal oxidation, the impedance matching of the MXene material is improved, and the wave absorption performance of the MXene material is significantly enhanced.

Description

Technical Field

[0001] This invention belongs to the field of electromagnetic wave absorbing materials technology, and relates to a wave absorbing material MXene@MnO2 and its preparation method. Background Technology

[0002] With the rapid development of electronic technology, the widespread application of electromagnetic waves in wireless communication, information transmission, and radar detection has made electromagnetic radiation a growing concern, seriously threatening human life and health, the normal operation of instruments, and the survivability of battlefield equipment. Materials with high electromagnetic wave loss capacity can effectively absorb electromagnetic waves and are important materials for addressing electromagnetic radiation problems and improving the stealth capabilities of battlefield equipment.

[0003] Transition metal carbides (MXenes) are a new class of two-dimensional materials composed of transition metals, carbon, and nitrogen. MXene materials exhibit great application potential in multiple fields due to their unique physical, chemical, and electrical properties. As two-dimensional materials, transition metal carbides (MXenes) possess large specific surface area, high conductivity, and polarization loss capability, making them potential high-performance microwave absorbing materials. Among them, Ti3C2T... x It has been extensively studied.

[0004] However, the impedance mismatch and other issues associated with transition metal carbides MXene limit their microwave absorption capabilities.

[0005] Therefore, a method is needed to improve the impedance matching of MXene materials to solve the above-mentioned technical problems. Summary of the Invention

[0006] The technical solution adopted by this invention to solve the technical problem is: a method for preparing the microwave absorbing material MXene@MnO2, comprising the following steps:

[0007] Step S1: Add MAX to hydrofluoric acid solution for etching to generate multilayer MXene; using MAX and hydrofluoric acid solution as raw materials, the Al atoms in the MAX phase are stripped by hydrofluoric acid to form Ti3C2. The exposed Ti atoms have good reactivity and readily react with H2O and HF acid to form compounds with -OH and -F, thus successfully obtaining multilayer MXene.

[0008] Step S2: Add the multilayer MXene generated in step S1 and potassium permanganate solution to hydrochloric acid solution and mix. Then, carry out a hydrothermal reaction of the mixed solution.

[0009] Step S3: Dry the product obtained in step S2 in a vacuum oven to obtain MXene@MnO2.

[0010] Preferably, in step S1, the concentration of the hydrofluoric acid solution is 30-50%.

[0011] More preferably, the concentration of the hydrofluoric acid solution is 35-45%.

[0012] Preferably, in steps S1 and S2, the ratio of the amount of MAX to the amount of potassium permanganate is 0.9-1.1g:1.0-3.0mmol.

[0013] Preferably, in step S2, the hydrothermal reaction temperature is 140-160℃ and the time is 4-8h.

[0014] More preferably, the hydrothermal reaction is carried out at a temperature of 145-155°C for a time of 5-7 hours.

[0015] Preferably, in step S3, the vacuum drying temperature is 70-90℃ and the drying time is 4-8h.

[0016] This invention also discloses a microwave absorbing material MXene@MnO2, which is prepared according to the above-mentioned preparation method of microwave absorbing material MXene@MnO2. The microwave absorbing material MXene@MnO2 is formed by combining multiple layers of MXene and large-pore square nanotubes of MnO2. The morphology of the microwave absorbing material MXene@MnO2 is formed by the growth of large-pore square nanotubes of MnO2 between the multiple layers of MXene.

[0017] The beneficial effects of this invention are:

[0018] 1. The MXene-based composite material and its preparation method disclosed in this invention have widely available raw materials, are environmentally friendly and sustainable, and can be mass-produced. By introducing interfacial polarization caused by the difference in conductivity between MnO2 and TiO2 generated by its own hydrothermal oxidation, the impedance matching of the MXene material is improved, which greatly enhances the microwave absorption performance of the MXene material.

[0019] 2. The MXene-based composite material obtained by the preparation method of the present invention is composed of two different structural units.

[0020] 3. In the MXene-based composite material disclosed in this invention, MnO2 crystal pillars are nucleated and grown on MXene sheets. However, the lattice parameters of the two are different, resulting in a large number of lattice defects. Furthermore, the introduction of air greatly improves the impedance matching of the multilayer MXene material, giving it excellent wave absorption performance. Attached Figure Description

[0021] Figure 1This invention provides XRD patterns of MXene-based composite materials, MnO2, and raw material MAX, which are used in the preparation of MXene@MnO2 and the method thereof.

[0022] Figure 2 This is a SEM image of the large-pore tetragonal nanotube MnO2 material prepared in Example 1 of this invention;

[0023] Figure 3 Here is a SEM image of the MXene-based composite material prepared in Example 1 of this invention;

[0024] Figure 4 Here is a SEM image of the MXene-based composite material prepared in Comparative Example 1 of this invention;

[0025] Figure 5 These are reflection loss diagrams of the MXene-based composite materials prepared in Example 1 and Comparative Example 1 of this invention;

[0026] Figure 6 These are electromagnetic parameter diagrams of the MXene-based composite materials prepared in Example 1 and Comparative Example 1 of this invention;

[0027] Figure 7 The images show the RCS values ​​of the MXene-based composite material and the perfect conductor PEC prepared in Example 1 and Comparative Example 1 of this invention. Detailed Implementation

[0028] The related technologies of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0029] refer to Figures 1-7 The MAX(Ti3AlC2) used in this embodiment was purchased from Jilin Yiyi Technology Co., Ltd.; hydrofluoric acid, potassium permanganate, and hydrochloric acid were purchased from Sinopharm Corporation.

[0030] Example 1

[0031] Add 1g of MAX powder to 10mL of 40% hydrofluoric acid solution and stir at a constant speed of 600rpm for 24h. Then, wash the product with deionized water by centrifugation at 3500rpm 3-5 times, 5 minutes each time, until the pH of the supernatant reaches approximately 6-7. Finally, place the obtained product in the upper part of a freeze dryer and dry for 24h. The resulting black powder is multilayer MXene.

[0032] The prepared multilayer MXene powder and 2 mmol of potassium permanganate were added to 30 mL of 0.1 mol / L hydrochloric acid solution and magnetically stirred at 600 rpm for 15 min. The stirred mixture was then added to the lining of a 46 mL hydrothermal reactor, which was sealed and heated in a vacuum drying oven for 6 h. After the reaction was complete and the mixture cooled naturally, the product was removed, washed five times with water in a centrifuge at 3500 rpm for 5 min, and then vacuum dried at 80 °C for 6 h to obtain MXene@MnO2.

[0033] Comparative Example 1

[0034] Following the method in Example 1, the concentration of hydrochloric acid was adjusted to 0.167 mol / L, the hydrothermal reaction temperature was adjusted to 120°C, and other experimental conditions remained the same.

[0035] Scanning electron microscope (SEM) image of the product prepared in Comparative Example 1 is shown below. Figure 6 As shown, by Figure 6 It can be seen that after changing the hydrochloric acid concentration and hydrothermal temperature, the MnO2 column structure grown from the product exhibits a solid structure.

[0036] The comparison shows that the strongest reflection loss of the embodiment of the present invention reaches -60.06dB, which is higher than the -48.08dB of the comparative example. Furthermore, it has a wider EAB (2.32GHz), thus achieving effective absorption over a wider frequency band. In addition, when electromagnetic waves are incident perpendicularly, the RCS value of the embodiment decreases more significantly than that of the comparative example when the electromagnetic waves are incident perpendicularly. Therefore, it can be concluded that the absorbing material MXene@MnO2 prepared by the method of the present invention improves the absorption performance of MXene materials.

[0037] In summary, the MXene-based composite material and its preparation method of the present invention have widely available raw materials, are environmentally friendly and sustainable, and can be mass-produced. By introducing interfacial polarization caused by the difference in conductivity between MnO2 and TiO2 generated by its own hydrothermal oxidation, the impedance matching of the MXene material is improved, which greatly enhances the microwave absorption performance of the MXene material. Therefore, the present invention has broad application prospects.

[0038] It should be emphasized that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a wave-absorbing material MXene@MnO 2, characterized in that, Includes the following steps: Step S1: Add MAX to the hydrofluoric acid solution for etching to generate multilayer MXene; Step S2: Add the multilayer MXene generated in step S1 and potassium permanganate solution to hydrochloric acid solution and mix. Then, carry out a hydrothermal reaction of the mixed solution. Step S3: Vacuum dry the product obtained in step S2 to obtain MXene@MnO2; The microwave absorbing material MXene@MnO2 is formed by combining multiple layers of MXene and large-pore square nanotubes of MnO2. The morphology of the microwave absorbing material MXene@MnO2 is formed by the growth of large-pore square nanotubes of MnO2 between the multiple layers of MXene.

2. The method for preparing the microwave absorbing material MXene@MnO2 according to claim 1, characterized in that, In step S1, the concentration of the hydrofluoric acid solution is 30-50%.

3. The method for preparing the microwave absorbing material MXene@MnO2 according to claim 2, characterized in that, The concentration of the hydrofluoric acid solution is 35-45%.

4. The method for preparing the microwave absorbing material MXene@MnO2 according to claim 1, characterized in that, In steps S1 and S2, the ratio of the amount of MAX to the amount of potassium permanganate is: 0.9-1.1 g: 1.0-3.0 mmol.

5. The method for preparing the microwave absorbing material MXene@MnO2 according to claim 1, characterized in that, In step S2, the hydrothermal reaction temperature is 140-160℃ and the time is 4-8 h.

6. The method for preparing the microwave absorbing material MXene@MnO2 according to claim 5, characterized in that, The hydrothermal reaction is carried out at a temperature of 145-155℃ for 5-7 hours.

7. The method for preparing the microwave absorbing material MXene@MnO2 according to claim 1, characterized in that, In step S3, the vacuum drying temperature is 70-90℃ and the drying time is 4-8h.

8. A microwave absorbing material MXene@MnO2, characterized in that, The microwave absorbing material MXene@MnO2 is prepared by the method described in any one of claims 1 to 7.

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