A FeCo@SiO2@1T / 2H-MoS2 electromagnetic wave absorption material and its preparation method and application

Abstract

The present invention relates to an FeCo@SiO2@1T / 2H-MoS2 electromagnetic wave absorption material, its preparation method, and application. A fishbone-shaped FeCo material is obtained by applying a strong magnetic field during hydrothermal synthesis, which is then coated with SiO2. Finally, a strong magnetic field hydrothermal method is used to generate 1T / 2H-MoS2 nanosheets on the surface of the FeCo@SiO2, resulting in a three-dimensional core-shell structure of FeCo@SiO2@1T / 2H-MoS2. The material's multi-gap dendritic nanostructure and surface MoS2 nanosheets give it superior microwave absorption performance.

Description

Technical Field

[0001] The present invention relates to the field of electromagnetic wave absorbing materials, and in particular to a FeCo@SiO2@1T / 2H-MoS2 electromagnetic wave absorbing material and a preparation method and application thereof. Background Art

[0002] With the advancement of technology, the widespread use of radar detection equipment and wireless communications, along with electronic devices such as mobile phones and computers, has brought significant convenience to people. However, this inevitably leads to electromagnetic pollution. Excessive electromagnetic energy not only harms human health, but also impacts industrial production, military communications, and the normal operation of mechanical equipment. In serious cases, it can also leak information, jeopardizing personal and national security. Therefore, the search for advanced electromagnetic wave absorbing materials to address electromagnetic wave pollution caused by electromagnetic radiation is of great research significance. Current research on electromagnetic wave absorption can be categorized into two types: magnetic loss materials and dielectric loss materials. Magnetic loss materials generally include ferrites, metal oxides, and magnetic alloy particles; dielectric loss materials generally include carbonaceous materials and conductive polymers. In recent years, due to the single composition of dielectric loss materials or magnetic loss materials, ideal absorption performance has been inadequate. Consequently, a growing number of researchers have begun combining electrical loss materials with magnetic loss materials, seeking ideal electromagnetic wave absorbing materials with a moderate dielectric constant and high magnetic permeability, based on impedance matching conditions.

[0003] Recent research has found that the magnetic loss material FeCo exhibits satisfactory electromagnetic wave absorption due to its high saturation magnetization and magnetic permeability. However, ferromagnets include magnetic metals (such as Fe and Co), which are easily oxidized, especially at the nanometer or micrometer scale. This degrades electromagnetic wave absorption performance over time. Furthermore, since a single magnetic loss material cannot achieve ideal absorption performance, dielectric loss materials are often required to improve impedance matching.

[0004] As a typical transition metal dichalcogenide, MoS2 has attracted great attention due to its unique electrical, optical and mechanical properties. Of particular interest is that stable semiconductor phase (2H) and metastable metal (1T) are the forms in which MoS2 exists. The electron concentration of 1T-MoS2 has been shown to be about 10 times that of the 2H phase. In addition, the metallic phase 1T-MoS2 exhibits superior conductivity and more significant dielectric loss characteristics compared to the traditional semiconductor 2H-MoS2. This can contribute to the optimization of impedance matching. In addition, the two-dimensional sheet structure of MoS2 can effectively reflect electromagnetic waves, thereby losing more electromagnetic waves.

[0005] The experimental and theoretical results of the present invention both indicate that the three-dimensional core-shell nanostructured material obtained by compounding FeCo alloy particles prepared by a strong magnetic field hydrothermal method can improve the electromagnetic wave absorption performance of the material. Summary of the Invention

[0006] This paper proposes a high-magnetic-field synthesis scheme for FeCo@SiO2@1T / 2H-MoS2 nanostructured electromagnetic wave absorbers. By applying a strong magnetic field during the hydrothermal synthesis process, a fishbone-shaped FeCo material is obtained. This is then coated with SiO2. Finally, a high-magnetic-field hydrothermal method is used again to form 1T / 2H-MoS2 nanosheets on the FeCo@SiO2 surface, resulting in a three-dimensional core-shell FeCo@SiO2@1T / 2H-MoS2 structure. The material's multi-gap dendritic nanostructure and surface MoS2 nanosheets contribute to its superior microwave absorption performance.

[0007] The present invention provides a FeCo@SiO2@1T / 2H-MoS2 electromagnetic wave absorption material, which is composed of stacked micron-sized particles. Each particle comprises, from the inside to the outside, a core layer, a SiO2 layer wrapped outside the core layer, and a 1T / 2H phase MoS2 layer wrapped outside the SiO2 layer; the core layer is composed of an alloy core with a three-dimensional fishbone structure, and the alloy core is composed of an Fe and Co alloy.

[0008] The present invention also provides an application of FeCo@SiO2@1T / 2H-MoS2 electromagnetic wave absorption material in electromagnetic absorption. When the matching thickness is 2.15 mm and the frequency is 10.04 GHz, the maximum reflection loss of the material reaches -50.15 dB; when the matching thickness is 1.5 mm, the effective bandwidth is 4.68 GHz; when the matching thickness is 3 mm, it also exhibits wave absorption performance at low frequencies of 2-8 GHz.

[0009] The present invention also provides a method for preparing a FeCo@SiO2@1T / 2H-MoS2 electromagnetic wave absorbing material, comprising the following steps:

[0010] Step 1: first, weighing a divalent Co salt and an Fe salt in a molar ratio of Co to Fe of 1:1, adding the salts to a mixed solution of water and anhydrous ethanol in a volume ratio of 1:1, and magnetically stirring until completely dissolved to obtain a solution A;

[0011] Then, under vigorous stirring, a mixed solution including NaOH and N2H4·H2O was added to solution A and stirred vigorously for 10 min to obtain solution B;

[0012] Transferring solution B to a reactor, applying a magnetic field, and using a strong magnetic field hydrothermal method to obtain alloy core nanoparticles; the alloy core nanoparticles are fishbone-shaped;

[0013] Step 2: adding the alloy core nanoparticles prepared in step 1 to an ethanol solution, stirring to disperse the alloy core nanoparticles, then dropwise adding NH3·H2O and (C2H5O)4Si, and continuing to stir the reaction. Finally, centrifuging and drying to obtain a FeCo@SiO2 product;

[0014] Step 3: ultrasonically disperse the FeCo@SiO2 product prepared in step 2 in deionized water, add CH4N2S and (NH4)6Mo7O 24 4H2O, stirring to obtain solution C;

[0015] Solution C was transferred to a reactor, a magnetic field was applied, and the reaction was carried out by a strong magnetic field hydrothermal method. Finally, FeCo@SiO2@1T-2H-MoS2 was obtained by drying.

[0016] Preferably, in step 1, the divalent Co salt and Fe salt are CoCl2·6H2O and FeCl3·6H2O, respectively, and the added amount of the Co salt and the Fe salt is 1.5 mmol; in step 1, the volume of the mixed solution composed of anhydrous ethanol and deionized water is 15 mL; in step 1, the mixed solution including NaOH and N2H4·H2O is prepared by mixing the 5 mol / L NaOH aqueous solution and the 50 wt% N2H4·H2O solution, and the added amount of the NaOH aqueous solution and the N2H4·H2O solution is 5 ml each.

[0017] Preferably, in step 1, the vigorous stirring time is 10 minutes; the applied magnetic field is 6 T, and the excitation and demagnetization rates are both 0.09 T / min; the temperature of the strong magnetic field hydrothermal reaction is 160° C., and the time is 10 hours.

[0018] Preferably, in step 2, the mass of the added alloy core nanoparticles is 0.2 g; in step 2, the volumes of anhydrous ethanol and deionized water in the ethanol solution are each 20 ml; in step 2, the amount of NH3·H2O added dropwise is 4 ml, and the amount of (C2H5O)4Si added dropwise is 0.4 ml; in step 2, the stirring before and after the dropwise addition of NH3·H2O and (C2H5O)4Si is both stirred at 24°C, and the stirring time after the dropwise addition of NH3·H2O and (C2H5O)4Si is 12 h.

[0019] Preferably, in step 3, the mass of the FeCo@SiO2 product is 0.2 g; the volume of the deionized water is 21.8 ml; the mass of CH4N2S is 0.3621 g; (NH4)6Mo7O24 The mass of 4H2O is 0.71045 g. In step 3, the applied magnetic field is 6 T, and the excitation and demagnetization rates are both 0.09 T / min.

[0020] Preferably, in step 3, the reaction temperature of the strong magnetic field hydrothermal reaction is 180° C.; and the reaction time of the strong magnetic field hydrothermal reaction is 18 h.

[0021] This invention provides a novel FeCo@SiO2@1T / 2H-MoS2 fishbone-shaped electromagnetic wave absorber. The fishbone-shaped FeCo is synthesized using a strong magnetic field hydrothermal method. To prevent sulfidation and oxidation, the FeCo is then coated with SiO2. Finally, a strong magnetic field hydrothermal method is used again to prepare 1T / 2H phase MoS2. This results in a three-dimensional core-shell FeCo@SiO2@1T / 2H-MoS2 electromagnetic wave absorber with a surface covered with flaky 1T / 2H-MoS2. This nanostructured absorber exhibits a wide effective absorption band and excellent electromagnetic wave absorption performance at a low thickness.

[0022] The present invention provides a method for preparing the above-mentioned two-dimensional nanostructured FeCo@SiO2@1T / 2H-MoS2 electromagnetic wave absorption material. This method does not require the use of highly toxic organic solvents, has simple steps, strong controllability, low cost, and can be used for large-scale industrial production.

[0023] The electromagnetic wave absorber of the present invention contains multiple three-dimensional spherical structures, each of which is composed of FeCo alloy particles, a SiO2 layer that prevents sulfidation wrapped around the outer layer of the particles, and a two-dimensional MoS2 sheet in the outermost layer, thus forming a three-dimensional spherical structure material with multiple gaps.

[0024] The preparation principle of the FeCo@SiO2@1T / 2H-MoS2 absorbing material of the present invention is as follows: A fishbone-shaped FeCo alloy particle chain is synthesized using a high-magnetic field, low-temperature hydrothermal method. Then, a SiO2 shell is formed on the FeCo surface using tetraethyl silicate under stirring in a water bath. Finally, a high-magnetic field hydrothermal method is used to generate 1T / 2H phase MoS2 nanosheets on the composite surface. The resulting ternary FeCo@SiO2@1T / 2H-MoS2 composite material increases magnetic losses due to the exchange resonance of the FeCo alloy and conductive losses due to the fishbone structure. Furthermore, the three-dimensional layered configuration effectively provides a larger effective position, extending the transmission path of electromagnetic waves that are repeatedly reflected and scattered. The two-dimensional MoS2 surface of the nanomaterial has a multi-gap structure with a large number of interfaces, allowing incident electromagnetic waves to be repeatedly reflected and scattered between the nanosheets, resulting in more efficient dissipation of the incident electromagnetic waves, thereby enabling the nanomaterial to exhibit superior microwave absorption performance.

[0025] Advantageous Effects of the Invention

[0026] (1) In the process of synthesizing FeCo, the present invention uses a strong magnetic field hydrothermal method to obtain a FeCo alloy composed of multiple rectangular parallelepipeds arranged in a fishbone pattern. This special FeCo alloy synthesized under a strong magnetic field of 6T does not form a common one-dimensional structure. The individual nanoparticles formed are closer to rectangular parallelepipeds and have a more regular grain structure. In addition, this fishbone-shaped FeCo structure has a certain effect on improving the material's conduction loss and impedance matching.

[0027] (2) In ordinary hydrothermal reactions, FeCo is easily sulfided by MoS2 during the reaction process, so SiO2 coating is needed to effectively prevent FeCo from being sulfided during the hydrothermal reaction, resulting in changes in the product and reducing the generation of impurities.

[0028] (3) The present invention uses 1T / 2H-MoS2 as the outermost layer for coating. The two-dimensional multi-gap structure of MoS2 can produce a large surface area, which can enhance the multiple reflections and scattering of incident waves, providing more contact points for electromagnetic waves. In addition, the introduction of the 1T phase increases the material's conductivity and dielectric loss properties, thereby improving the material's wave absorption performance.

[0029] (4) The present invention also does not require the use of highly toxic chemical reagents for preparation. The method is simple, highly controllable, and low-cost, making it suitable for large-scale industrial production. This important result also provides a strong theoretical basis and experimental foundation for the research and development of ideal microwave absorbing materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the specific embodiments or the description of the prior art. Hereinafter, some specific embodiments of the present invention will be described in detail in an illustrative and non-limiting manner with reference to the drawings. The same reference numerals in the drawings indicate the same or similar components or parts. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings:

[0031] Figure 1 X-ray diffraction patterns of 6T-FeCo@SiO2@6T-MoS2 and 0T-FeCo@SiO2@0T-MoS2 prepared in the present invention;

[0032] Figure 2 This is a SEM image of 6T-FeCo@SiO2@6T-MoS2 prepared in Example 1 of the present invention;

[0033] Figure 3This is an SEM image of 0T-FeCo@SiO2@0T-MoS2 prepared in Example 2 of the present invention;

[0034] Figure 4 This is a SEM image of 6T-FeCo prepared in step 1 of Example 1 of the present invention;

[0035] Figure 5 This is an SEM image of 0T-FeCo prepared in step 1 of Example 2 of the present invention;

[0036] Figure 6 These are the T hysteresis loop images of 6T-FeCo@SiO2@6T-MoS2 and 0T-FeCo@SiO2@0T-MoS2 prepared in Example 2 of the present invention;

[0037] Figure 7 This is a reflection loss diagram of 6T-FeCo@SiO2@6T-MoS2 prepared in Example 1 of the present invention;

[0038] Figure 8 This is a reflection loss diagram of 0T-FeCo@SiO2@0T-MoS2 prepared in Example 2 of the present invention. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0040] The embodiments of the present invention are further described below with reference to the accompanying drawings.

[0041] The preparation method of the FeCo@SiO2@1T / 2H-MoS2 absorbing material of the present invention specifically comprises the following steps:

[0042] Example 1

[0043] Step 1: First, 1.5 mmol of each CoCl2·6H2O and FeCl3·6H2O (in a 1:1 ratio) was weighed and added to a 15 ml mixed solution of deionized water and anhydrous ethanol (in a 1:1 ratio). The mixture was then magnetically stirred until completely dissolved. Then, a certain amount of a mixed solution of 5 ml of NaOH (5 mol / L) and 5 ml of N2H4·H2O (50 wt%) was added under vigorous stirring and stirred vigorously for 10 minutes. The resulting mixed solution was transferred to a 28 ml stainless steel reactor lined with polytetrafluoroethylene and subjected to a 6 T magnetic field. The reaction was carried out using a strong magnetic field hydrothermal method at 160°C for 10 hours. Finally, the mixture was centrifuged and dried to obtain fishbone-shaped 6T-FeCo nanoparticles.

[0044] Step 2: First, 0.2 g of FeCo prepared in step 1 was added to a mixed solution of 20 ml of anhydrous ethanol and 20 ml of deionized water, and then mechanically stirred for 30 min in a water bath at 24 ° C to disperse FeCo. Subsequently, 4 ml of NH3·H2O and 0.4 ml of (C2H5O)4Si were added dropwise to the mixed solution, and mechanical stirring was continued for 12 h in a water bath at 24 ° C. Finally, the product was centrifuged and dried to collect the FeCo@SiO2 product.

[0045] Step 3: 0.2 g of 6T-FeCo@SiO2 prepared in step 2 was ultrasonically dispersed in deionized water, and 0.3621 g of CH4N2S and 0.71045 g of (NH4)6Mo7O were added. 24 4H2O, stirred vigorously for 30 min. The mixed solution was transferred to a PTFE-lined stainless steel reactor (28 ml). A 6T magnetic field was applied and the reaction was carried out by a strong magnetic field hydrothermal method at 180°C for 18 h. Finally, 6T-FeCo@SiO2@6T-MoS2 was obtained by magnetic collection and drying.

[0046] Example 2

[0047] Step 1: First, 1.5 mmol of each CoCl2·6H2O and FeCl3·6H2O (in a 1:1 ratio) was weighed and added to a 15 ml mixed solution of deionized water and anhydrous ethanol (in a 1:1 ratio). The mixture was magnetically stirred until completely dissolved. Then, a certain amount of a mixed solution of 5 ml of NaOH (5 mol / L) and 5 ml of N2H4·H2O (50 wt%) was added under vigorous stirring and vigorously stirred for 10 minutes. The resulting mixed solution was transferred to a PTFE-lined stainless steel reactor (28 ml), a 0 T magnetic field was applied, and the reaction was carried out using a strong magnetic field hydrothermal method at 160°C for 10 hours. Finally, the mixture was centrifuged and dried to obtain fishbone-shaped 0T-FeCo nanoparticles.

[0048] Step 2: First, 0.2 g of FeCo prepared in step 1 was added to a mixed solution of 20 ml of anhydrous ethanol and 20 ml of deionized water, and then mechanically stirred for 30 min in a water bath at 24 ° C to disperse FeCo. Subsequently, 4 ml of NH3·H2O and 0.4 ml of (C2H5O)4Si were added dropwise to the mixed solution, and mechanical stirring was continued for 12 h in a water bath at 24 ° C. Finally, the product was centrifuged and dried to collect the 0T-FeCo@SiO2 product.

[0049] Step 3: Take 0.2g of FeCo@SiO2 prepared in step 2 and ultrasonically disperse it in deionized water, add 0.3621g of CH4N2S and 0.71045g of (NH4)6Mo7O 244H2O, stirred vigorously for 30 min. The mixed solution was transferred to a PTFE-lined stainless steel reactor (28 ml). A 0T magnetic field was applied and the reaction was carried out by a strong magnetic field hydrothermal method at 180°C for 18 h. Finally, 0T-FeCo@SiO2@0T-MoS2 was obtained by magnetic collection and drying.

[0050] Figure 1 The XRD patterns of 6T-FeCo@SiO2@6T-MoS2 and 0T-FeCo@SiO2@0T-MoS2 are shown. Figure 1 In the XRD pattern, the diffraction peaks at 2θ = 44.680°, 65.110° and 82.400° correspond to the (110), (200) and (211) of FeCo. The diffraction peaks at 2θ = 32.298°, 55.212° and 58.479° correspond to the (100), (106) and (110) of 2H-MoS2, while the (002) and (004) corresponding to the 1T phase are located at 2θ = 8.940° and 17.249°, respectively. Figure 1 The diffraction peaks are intense and sharp, and 6T-FeCo@SiO2@6T-MoS2 exhibits higher crystallinity than 0T-FeCo@SiO2@0T-MoS2, indicating that applying a strong magnetic field during the hydrothermal reaction enhances the crystallinity of FeCo. The XRD pattern demonstrates the successful synthesis of the 6T-FeCo@SiO2@6T-MoS2 composite.

[0051] Figure 2 and Figure 3 These are the SEM images of 6T-FeCo@SiO2@6T-MoS2 and 0T-FeCo@SiO2@0T-MoS2. It can be seen from the figure that the MoS2 flakes on the surface of 6T-FeCo@SiO2@6T-MoS2 prepared under a strong magnetic field of 6T are significantly smaller than those of 0T-FeCo@SiO2@0T-MoS2, which provides enough voids for the composite material.

[0052] Figure 4 and Figure 5 The SEM images of 6T-FeCo and 0T-FeCo respectively show that compared with 0T-FeCo prepared under a 6T strong magnetic field, the shape of the single nanoparticles of 6T-FeCo is closer to that of a rectangular parallelepiped, and they are connected at the diagonals to form a three-dimensional fishbone structure. This structure plays a certain role in improving the conductivity loss and impedance matching of the material.

[0053] Figure 6 The hysteresis loops of 6T-FeCo@SiO2@6T-MoS2 and 0T-FeCo@SiO2@0T-MoS2 are shown in Figure 2. Figure 6It can be seen that the saturation magnetization intensity of the 6T-FeCo@SiO2@6T-MoS2 composite material is greater than that of the 0T-FeCo@SiO2@0T-MoS2 composite material, indicating that the magnetic properties of the composite material prepared under a magnetic field are improved to a certain extent.

[0054] Figure 7 The reflection loss diagram of 6T-FeCo@SiO2@6T-MoS2 is shown in Figure 2. Figure 7 It can be seen that 6T-FeCo@SiO2@6T-MoS2 exhibits excellent electromagnetic wave absorption performance. When the matching thickness is 2.15mm and the frequency is 10.04GHz, the maximum reflection loss can reach -50.15dB; when the thickness is 1.5mm, the optimal effective bandwidth is 4.68GHz, and when the thickness is 3mm, it also has certain absorption performance at low frequencies (2-8GHz).

[0055] Figure 8 The reflection loss diagram of 0T-FeCo@SiO2@0T-MoS2 is shown in Figure 2. Figure 8 It can be seen that 6T-FeCo@SiO2@6T-MoS2 exhibits good electromagnetic wave absorption performance. When the matching thickness is 1.5 mm and the frequency is 15.68 GHz, the maximum reflection loss is -17.82 dB and the optimal effective bandwidth is 5.64 GHz.

[0056] The wave-absorbing performance of the 6T-FeCo@SiO2@6T-MoS2 composite material of the present invention mainly comes from the fact that the FeCo alloy improves the magnetic permeability of the composite material, while the SiO2 layer is used to prevent FeCo from being sulfided, and then MoS2 is grown and coated on the outermost surface. The large surface area and sufficient voids of MoS2 and the generated 1T phase MoS2 further improve the dielectric properties. The multi-layer core-shell structure further extends the transmission path of electromagnetic waves with multiple reflections and scatterings. The existence of multiple loss mechanisms ensures strong absorption of the incident electromagnetic waves. Therefore, the present invention can still achieve strong reflection loss and a wide effective absorption band at a relatively low thickness.

[0057] The above description is only part of the specific implementation methods of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any person familiar with the art within the technical scope disclosed in the present invention should be covered by the protection scope of the present invention.

Claims

1. A FeCo@SiO2@1T / 2H-MoS2 electromagnetic wave absorbing material, characterized by: The material is composed of stacked micron-sized particles, each of which includes, from the inside to the outside, a core layer, a SiO2 layer wrapped around the core layer, and a 1T / 2H phase MoS2 layer wrapped around the SiO2 layer; The core layer is composed of an alloy core with a three-dimensional fishbone structure, and the alloy core is composed of an Fe and Co alloy. The alloy core preparation method includes the following steps: first, weighing a divalent Co salt and an Fe salt in a molar ratio of Co to Fe of 1:1, adding the salt to a mixed solution of water and anhydrous ethanol in a volume ratio of 1:1, and magnetically stirring until completely dissolved to obtain a solution A; the divalent Co salt and the Fe salt are CoCl2·6H2O and FeCl3·6H2O, respectively; Then, under vigorous stirring, a mixed solution including NaOH and N2H4·H2O was added to solution A and stirred vigorously for 10 min to obtain solution B; Solution B was transferred to a reactor, a magnetic field was applied, and alloy core nanoparticles were obtained using a strong magnetic field hydrothermal method. The alloy core nanoparticles had a three-dimensional fishbone shape. The temperature of the strong magnetic field hydrothermal method was 160°C, the applied magnetic field was 6 T, and the excitation and demagnetization rates were both 0.09 T / min.

2. The use of the FeCo@SiO2@1T / 2H-MoS2 electromagnetic wave absorption material in electromagnetic absorption according to claim 1, characterized in that: When the matching thickness is 2.15 mm and the frequency is 10.04 GHz, the maximum reflection loss of the material reaches -50.15 dB; when the matching thickness is 1.5 mm, the effective bandwidth is 4.68 GHz; when the matching thickness is 3 mm, it also exhibits absorbing performance at low frequencies of 2-8 GHz.

3. The method for preparing a FeCo@SiO2@1T / 2H-MoS2 electromagnetic wave absorbing material according to claim 1, characterized in that: The steps include: Step 1: First, weigh a divalent Co salt and an Fe salt in a 1:1 molar ratio of Co and Fe elements, add them to a mixed solution obtained by mixing water and anhydrous ethanol in a 1:1 volume ratio, and stir magnetically until completely dissolved to obtain solution A; The divalent Co salt and Fe salt are CoCl2·6H2O and FeCl3·6H2O respectively; Then, under vigorous stirring, a mixed solution including NaOH and N2H4·H2O was added to solution A and stirred vigorously for 10 min to obtain solution B; Solution B was transferred to a reactor, a magnetic field was applied, and alloy core nanoparticles were obtained by a strong magnetic field hydrothermal method; The alloy core nanoparticles are three-dimensional fishbone-shaped; the temperature of the strong magnetic field hydrothermal method is 160°C, the applied magnetic field is 6 T, and the excitation and demagnetization rates are both 0.09 T / min; Step 2: adding the alloy core nanoparticles prepared in step 1 to an ethanol solution, stirring to disperse the alloy core nanoparticles, then dropwise adding NH3·H2O and (C2H5O)4Si, and continuing to stir the reaction. Finally, centrifuging and drying to obtain a FeCo@SiO2 product; Step 3: ultrasonically disperse the FeCo@SiO2 product prepared in step 2 in deionized water, add CH4N2S and (NH4)6Mo7O 24 4H2O, stirring to obtain solution C; Solution C was transferred to a reactor, a magnetic field was applied, and the reaction was carried out by a strong magnetic field hydrothermal method, and finally dried to obtain FeCo@SiO2@1T-2H-MoS2; In step 3, the reaction temperature of the high magnetic field hydrothermal method is 180°C, the applied magnetic field is 6T, and the excitation and demagnetization rates are both 0.09 T / min.

4. The method for preparing a FeCo@SiO2@1T / 2H-MoS2 electromagnetic wave absorbing material according to claim 3, characterized in that: In step 1, the amount of Co salt and Fe salt added was 1.5 mmol; In step 1, the volume of the mixed solution consisting of anhydrous ethanol and deionized water is 15 mL; In step 1, the mixed solution including NaOH and N2H4·H2O is prepared by mixing a 5 mol / L NaOH aqueous solution and a 50 wt% N2H4·H2O solution, and the added amount of the NaOH aqueous solution and the N2H4·H2O solution is 5 ml each.

5. The method for preparing a FeCo@SiO2@1T / 2H-MoS2 electromagnetic wave absorbing material according to claim 4, characterized in that: In step 1, the vigorous stirring time is 10 min; the strong magnetic field hydrothermal method time is 10 h.

6. The method for preparing a FeCo@SiO2@1T / 2H-MoS2 electromagnetic wave absorbing material according to claim 3, characterized in that: In step 2, the mass of the added alloy core nanoparticles was 0.2 g; In step 2, the volume of anhydrous ethanol and deionized water in the ethanol solution is 20 ml each; In step 2, 4 ml of NH3·H2O and 0.4 ml of (C2H5O)4Si were added dropwise; In step 2, the stirring before and after the dropwise addition of NH3·H2O and (C2H5O)4Si is performed at 24°C, and the stirring time after the dropwise addition of NH3·H2O and (C2H5O)4Si is 12 h.

7. The method for preparing a FeCo@SiO2@1T / 2H-MoS2 electromagnetic wave absorbing material according to claim 3, characterized in that: In step 3, the mass of the FeCo@SiO2 product is 0.2 g; the volume of the deionized water is 21.8 ml; the mass of CH4N2S is 0.3621 g; (NH4)6Mo7O 24 The mass of 4H2O is 0.71045 g.

8. The method for preparing a FeCo@SiO2@1T / 2H-MoS2 electromagnetic wave absorbing material according to claim 7, characterized in that: In step 3, the reaction time of the strong magnetic field hydrothermal method is 18 h.

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