Core-shell structure MoS 2 @VO 2 Composite material, preparation method and application

Abstract

The present invention discloses a core-shell structured MoS2@VO2 composite material, a preparation method and an application. The steps of the method for preparing the composite material are as follows: S1: Preparation of hollow VO2: S11: Dissolve V2O5 and C2H2O4·2H2O in deionized water, denoted as mixed solution C; S12: Add isopropanol to mixed solution C for reaction to obtain hollow VO2; S2: Preparation of MoS2@VO2 composite material: S21: Dissolve the hollow VO2 prepared in S1 in deionized water, denoted as mixed solution A; S22: Dissolve sodium molybdate and thiourea in deionized water, denoted as mixed solution B; S23: Mix and react mixed solution A in S21 and mixed solution B in S22; S24: After the reaction, centrifuge, wash and dry to obtain the MoS2@VO2 composite material. The present invention prepares a core-shell structured MoS2@VO2 composite material with a synergistic effect of multiple loss pathways through a simple hydrothermal method. The RL min reaches -56.78 dB at 3.0 mm, and the EAB covers the entire X-band, indicating that the composite material exhibits good electromagnetic absorption performance.

Description

Technical Field

[0001] The present invention relates to the technical field of wave - absorbing materials, and particularly to a core - shell structure MoS 2 @VO 2 composite material, a preparation method and an application thereof. Background Art

[0002] With the in - depth development of communication engineering and 6G technology, the electromagnetic wave pollution caused by it has become a difficult problem interfering with the operation of equipment. The use of electromagnetic waves of various wavelengths has brought great convenience to human activities, but the harm to human health and the problem of electromagnetic pollution are also becoming increasingly serious. Therefore, the development of efficient electromagnetic wave absorption materials has become one of the new scientific hotspots. Especially to meet the needs of current Internet applications and environmental problems, one of the solutions to this problem is to develop electromagnetic wave absorption materials with potential in specific frequency bands.

[0003] In the field of electromagnetic wave absorption, the use of double - semiconductor composite materials is relatively less. The main research objects are generally carbon materials, magnetic materials, MOF materials and aerogel materials. Constructing a core - shell structure is an effective strategy to enrich the phase interface in terms of morphology control. Han et al. designed a flexible carbon fiber@ZIF - 67 material modified with MoS 2 2, achieving an effective absorption bandwidth (EAB) of up to 12.5 GHz. Ma et al. designed an embedded MoS 2 -PANI nanocomposite material, which has good microwave absorption performance (minimum reflection loss (RL min )=-59.78 dB, EAB = 3.12 GH) through in - situ polymerization. Designing absorbers in specific bands has special applications in the field of electromagnetic wave absorption. Wang et al. designed a sandwich - structured absorber (Fe@B 2 O 3 / MoS 2 / Fe@B 2 O 3 ), with a minimum reflection loss value of - 35.9 dB, achieving effective absorption in the entire X - band. Therefore, the purpose of the present invention is to prepare a composite material with good wave - absorbing performance based on MoS 2 . Summary of the Invention

[0004] The present invention provides a core - shell structure MoS 2 @VO 2 composite material, a preparation method and an application thereof. By a simple hydrothermal method, a core - shell structure MoS 2 @VO 2 composite material with a synergistic effect of multiple loss pathways is prepared, and this composite material exhibits good electromagnetic absorption performance.

[0005] The preparation method of the core-shell structure MoS 2 @VO 2 composite material is as follows:

[0006] S1: Preparation of hollow VO 2 .

[0007] S2: Preparation of MoS 2 @VO 2 composite material

[0008] S21: Dissolve the hollow VO prepared in S1 2 in deionized water, denoted as mixture A;

[0009] S22: Dissolve sodium molybdate and thiourea in deionized water, denoted as mixture B;

[0010] S23: Mix and react mixture A in S21 and mixture B in S22;

[0011] S24: After the reaction, centrifuge, wash and dry to obtain MoS 2 @VO 2 composite material.

[0012] Preferably, the preparation method of the hollow VO 2 is as follows:

[0013] S11: Dissolve V 2 O 5 and C 2 H 2 O 4 ·2H 2 O in deionized water, denoted as mixture C;

[0014] S12: Add isopropanol to mixture C for reaction to obtain hollow VO 2 .

[0015] Preferably, the molar ratio of V 2 O 5 and C 2 H 2 O 4 ·2H 2 O is 1:2 - 4.

[0016] Preferably, the dissolution temperature in S11 is 70 - 90 °C and the stirring time is 40 - 80 min.

[0017] Preferably, the reaction temperature in S12 is 180 - 220 °C and the reaction time is 10 - 14 h.

[0018] Preferably, the hollow VO2 The mass ratio of sodium molybdate to thiourea is 1:1 - 15:1 - 15.

[0019] Preferably, the reaction temperature in S23 is 180 - 220 °C, and the reaction time is 20 - 28 h.

[0020] Preferably, the drying temperature in S24 is 55 - 65 °C, and the time is 10 - 14 h.

[0021] The core - shell structure MoS 2 @VO 2 composite material prepared by the above - mentioned method of the present invention.

[0022] The above - mentioned core - shell structure MoS 2 @VO 2 Application of the composite material in electromagnetic wave absorption.

[0023] Advantageous technical effects of the present invention:

[0024] The present invention prepares a core - shell structure MoS 2 @VO 2 composite material with a synergistic effect of multiple loss pathways through a simple hydrothermal method. The unique core - shell structure of this composite material is formed by the uniform growth of flaky MoS 2 on the surface of hollow VO 2 . And with the change of the MoS 2 loading rate, the spheres show groove structures of different degrees. The composite materials are well - combined, and a large number of heterojunction structures are formed between the two phases. The properties of the two materials complement each other, improving the impedance matching characteristics of the composite material; in addition, the multi - polarization behavior promotes the absorption of electromagnetic waves by the composite material. The RL min of the VM - 2 composite material reaches - 56.78 dB at 3.0 mm, and the EAB covers the entire X - band, indicating that the composite material exhibits good electromagnetic absorption performance. The preparation of the core - shell structure composite material with semiconductor heterojunctions of the present invention is an effective strategy for achieving microwave absorption in a specific band. Description of the Drawings

[0025] Figure 1 Schematic diagram of the synthesis process of the MoS 2 @VO 2 composite material proposed by the present invention;

[0026] Figure 2 XRD patterns of (a) VM - 1, VM - 2, VM - 3 and MoS 2 ; (b) XPS spectra of VM - 1, VM - 2 and VM - 3; (c - f) V 2p, O 1s, Mo 3d, S 2p spectra;

[0027] Figure 3 SEM images of (a-i) VM-1, VM-2, and VM-3 proposed by the present invention; (j) SEM mapping image of VM-2;

[0028] Figure 4 TEM images of (a-i) VM-1, VM-2, and VM-3 proposed by the present invention; (j) TEM mapping image of VM-2;

[0029] Figure 5 Two-dimensional reflection loss curves of (a-c) VM-1, VM-2, and VM-3 proposed by the present invention; (d) bar chart of electromagnetic absorption performance of VM-1, VM-2, and VM-3;

[0030] Figure 6 Optimal electromagnetic wave absorption performance of (a) VM-2 proposed by the present invention; (b) performance comparison chart;

[0031] Figure 7 (a) ε′; (b) ε′; (c) tanδ of VM-1, VM-2, and VM-3 proposed by the present invention ε ; (d) μ′; (e) μ′ and (f) tanδ μ curves;

[0032] Figure 8 (a) impedance matching curve and (b) attenuation constant (α) curve of VM-1, VM-2, and VM-3 proposed by the present invention;

[0033] Figure 9 Cole-Cole curves of VM-1, VM-2, and VM-3 proposed by the present invention;

[0034] Figure 10 Schematic diagram of electromagnetic absorption mechanism of MoS 2 @VO 2 microspheres;

[0035] Figure 11 Simulated RCS of (a) PEC, VM-1, VM-2, and VM-3 at different incident angles proposed by the present invention; (b) RCS reduction achieved by subtracting the composite material from PEC; (c-f) simulation results of PEC, VM-1, VM-2, and VM-3. Detailed implementation manner

[0036] Sodium molybdate dihydrate (Na 2 MoO 4 ·2H 2 O, 99%) and thiourea (CH4N2S, 99%) and ethanol (CH 3 CH 2OH, 99%), vanadium pentoxide (V 2 O 5 , 99%), oxalic acid dihydrate (C 2 H 2 O 4 ·2H 2 O, 99%) were all purchased from Aladdin Chemical Reagent Co., Ltd.

[0037] Example 1

[0038] The preparation method of the core-shell structure MoS 2 @VO 2 composite material is as follows:

[0039] S1: Preparation of hollow VO 2

[0040] Dissolve V 2 O 5 (3.3 mmol) and C 2 H 2 O 4 ·2H 2 O (10.0 mmol) in 20 mL of deionized water, and continuously stir at 80 °C for 1 hour; then add the obtained blue solution (5.0 mL) to isopropanol (60.0 mL) and stir for 20 minutes, and finally carry out the reaction in a hydrothermal pot at 200 °C and maintain for 12 hours to obtain hollow VO 2 .

[0041] S2: Preparation of MoS 2 @VO 2 composite material

[0042] Add 0.05 g of VO 2 to 20 mL of deionized water and ultrasonically treat for 30 minutes. At the same time, dissolve 2.25 mmol of sodium molybdate (0.54 g) and 6.75 mmol of thiourea (0.51 g) in 40 mL of deionized water, and magnetically stir for 25 minutes until completely dissolved; then mix the two solutions evenly, transfer them to a 100 mL stainless steel reactor lined with polytetrafluoroethylene, place the reactor in an electrothermal blast furnace, set the temperature to 200 °C, and continue for 24 hours; after the reaction is completed, cool to room temperature, obtain the reaction product by centrifugation and washing, and dry it in a vacuum furnace at 60 °C for 12 hours to obtain MoS 2 @VO 2 composite material, denoted as VM-1.

[0043] Example 2

[0044] The core-shell structure MoS 2 @VO 2 ​The preparation method of the composite material is as follows:

[0045] S1: Preparation of hollow VO 2

[0046] Dissolve V 2 O 5 (3.3 mmol) and C 2 H 2 O 4 ·2H 2 O (10.0 mmol) in 20 mL of deionized water, and continuously stir for 1 hour at 80 °C; then add the obtained blue solution (5.0 mL) to isopropanol (60.0 mL) and stir for 20 minutes, and finally carry out the reaction in a hydrothermal pot at 200 °C and maintain for 12 hours to obtain hollow VO 2 .

[0047] S2: Preparation of MoS 2 @VO 2 composite material

[0048] Add 0.12 g of VO 2 to 20 mL of deionized water and ultrasonically treat for 30 minutes. At the same time, dissolve 2.25 mmol of sodium molybdate (0.54 g) and 6.75 mmol of thiourea (0.51 g) in 40 mL of deionized water, and magnetically stir for 25 minutes until completely dissolved; then mix the two solutions evenly, transfer them to a 100 mL stainless steel reactor lined with polytetrafluoroethylene, place the reactor in an electrothermal blast furnace, set the temperature to 200 °C, and continue for 24 hours; after the reaction is completed, cool to room temperature, obtain the reaction product by centrifugation and washing, and dry it in a vacuum furnace at 60 °C for 12 hours to obtain MoS 2 @VO 2 composite material, denoted as VM-2.

[0049] Example 3

[0050] The preparation method of the core-shell structure MoS 2 @VO 2 composite material provided by the present invention is as follows:

[0051] S1: Preparation of hollow VO 2

[0052] Dissolve V 2 O 5 (3.3 mmol) and C 2 H 2 O 4 ·2H 2 ​​O (10.0 mmol) was dissolved in 20 mL of deionized water and continuously stirred at 80 °C for 1 hour; subsequently, the obtained blue solution (5.0 mL) was added to isopropanol (60.0 mL) and stirred for 20 minutes. Finally, the reaction was carried out in a hydrothermal reactor at 200 °C for 12 hours to obtain hollow VO 2 .

[0053] S2: MoS 2 @VO 2 Preparation of composite materials

[0054] 0.28 g of VO 2 was added to 20 mL of deionized water and ultrasonicated for 30 minutes. Meanwhile, 2.25 mmol of sodium molybdate (0.54 g) and 6.75 mmol of thiourea (0.51 g) were dissolved in 40 mL of deionized water and magnetically stirred for 25 minutes until completely dissolved; then the two solutions were mixed evenly and transferred to a 100 mL stainless-steel reactor lined with polytetrafluoroethylene. The reactor was placed in an electrothermal blast furnace with the temperature set at 200 °C for 24 hours; after the reaction was completed, it was cooled to room temperature, and the reaction product was obtained by centrifugation and washing, and dried in a vacuum furnace at 60 °C for 12 hours to obtain MoS 2 @VO 2 composite material, denoted as VM-3.

[0055] MoS 2 @VO 2 The crystal structure of the MoS 2 @VO 2The crystal structure of the composite material was analyzed by an X-ray diffractometer (XRD, D8-Advance, Cu-Kα radiation, Bruker, Japan). The surface chemical elements and their bonding states of the samples were tested by X-ray photoelectron spectroscopy (XPS, ThermoFisher Scientific Inc. ESCALAB MK, USA). The morphology and composite effect of the samples were analyzed by scanning electron microscopy (SEM, FEI Sirion2000, FEI Company, Netherlands) and transmission electron microscopy (TEM, FEI Talos F200X, JEOL Ltd., Japan). A Raman spectrometer (Renishaw-2000, Renishaw, UK) was used to analyze the molecular structure research. Six sets of samples were made into rings with a thickness of 2 mm. The electromagnetic parameters were obtained by a vector network analyzer (AV3629D, CETC 41st Institute, China).

[0056] As Figure 2 (a) shows, pure VO 2 crystal form and MoS 2 @VO 2 The XRD pattern of the composite material shows the crystal structure information of the material. Referring to the standard card (JCPDS card No. 82-0661), the characteristic peaks of VO 2 monomer are located at 27.8°, 33.4°, 36.9°, 42.2° and 55.5°, and its diffraction peaks are assigned to the (011), (-102), (-211), (210) and (211) crystal planes respectively. After coating MoS 2 on the surface of VO 2 , the composite material mainly shows characteristic peaks at the positions of 14.4°, 33.5°, 39.5°, 49.8° and 60.1°, which are assigned to the (002), (101), (103), (105) and (008) crystal planes of MoS 2 . Referring to the standard card number 37-1492, analyzing from the overall image, with the increase of MoS 2 content, the intensity of the characteristic peaks is stronger. The presence of the characteristic peaks of VO 2 can also be observed in all three samples, especially in VM-3, but due to the coating and the lighter VO 2 , the characteristic peaks of MoS 2 are more obvious.

[0057] Figure 2 (b-f) shows the XPS patterns of these three groups of samples. By analyzing the exothermal chemical information of the materials, the main apparent element information of the samples can be obtained, including V, O, Mo and S (as Figure 2(as shown in (c-f)). Among them, the characteristic peak of V 2p was decomposed to obtain three sub-peaks located at 530.0 eV, 523.9 eV, and 517.0 eV, which were assigned to VO 4+ , V 2p 3 / 2 and V 2p 1 / 2 , indicating that the preparation of VO 2 is better and its chemical properties are more stable. For the splitting results of O 1s, the characteristic peaks located at 530.1, 513.4, and 532.5 eV correspond to metal oxygen, defective oxygen, and adsorbed oxygen respectively, which are the result of the combined action of metal-oxygen bonding and chemical reactions during the material synthesis process. In addition, among the deconvolution peak results of Mo 3d, the four peaks appearing at 226.0, 228.9, 232.1, and 235.9 eV are consistent with the characteristic peaks of S 2s, Mo 4+ 3d 5 / 2 , Mo 4+ 3d 3 / 2 and Mo 6+ 3d 3 / 2 respectively ( Figure 2 e). This is consistent with the binding energy results of MoS 2 crystals reported previously, indicating the presence of Mo 4+ (MoS 2 ) in the material. In particular, there is a satellite peak at 235.9 eV in the splitting results, which is inferred to be due to the presence of Mo-C and Mo-S-C because of the interaction with air at the MoS 2 interface. In the S 2p spectrum ( Figure 2 f), the characteristic peaks at 160.3 eV and 162.4 eV correspond to the S 2p 3 / 2 and 2p 1 / 2 orbits. These analyses further show that the combination of MoS 2 and VO 2 is more successful, and different binding modes inside the material can cause different degrees of polarization loss, which in turn effectively enhances the electromagnetic wave loss ability of the composite material.

[0058] To further analyze the microscopic morphology of the composite material and the specific binding morphology, scanning electron microscope tests were performed on the three groups of samples ( Figure 3 ). Generally speaking, the morphology of the composite material in the three groups of samples shows a typical core-shell structure. During the hydrothermal process, MoS 2 was used to wrap the surface of the VO 2 flower ball. Through the change of the coating amount, the surface groove structure of the composite microspheres also shows a characteristic of uniform change. Obviously, the flaky MoS 2 did not completely cover the surface of VM-1, and obvious pits appeared on the material. The coating effect of VM-2 is the best, and MoS2 It is uniformly coated on the material surface. For VM-3, some microspheres seem to be over-coated and have holes. Combining with the SEM-EDS results of VM-2, MoS 2 @VO 2 The elemental distribution of the microspheres is uniform, the bonding state is good, and the core-shell structure strategy is well applied. MoS 2 @VO 2 The groove structure on the surface of the microspheres and the clustering effect presented by the overall sample are beneficial to the scattering of incident electromagnetic waves, while the rough surface of the flower-like VO 2 is beneficial to the formation of a large number of heterojunction contact points during the MoS 2 coating process, thereby generating more polarization effects to attenuate the incident electromagnetic waves.

[0059] With the help of TEM images ( Figure 4 a-j), the combination of MoS 2 and VO 2 can be observed more carefully. In the TEM images of the three groups of samples, the outer gauze-like shell is MoS 2 , and it can be observed that it grows uniformly on the surface of the sphere in VM-1, and there are also MoS 2 agglomerates around the sphere. The same is true for VM-2 and VM-3, but in VM-2, MoS 2 also has protruding parts on the surface of the sphere during the growth process, which leads to more uneven structures. When the external electromagnetic field changes, it will cause more inconsistent electron movement speeds, which in turn leads to polarization behavior. The TEM-EDS characterization of VM-2 shows that the spheres are interconnected, and hollow VO 2 spheres can be seen through the elemental distribution state. Combining with the images of VO 2 in the supporting material, it can be determined that the spheres are hollow structures and the materials are well combined. The well-combined core-shell structure and the interconnected contact surfaces between the spheres are beneficial to the generation of phase interfaces, and the hollow sphere structure is also beneficial to the incident electromagnetic waves entering the material and being attenuated repeatedly.

[0060] To study the influence of the encapsulation degree of MoS 2 and the core-shell structure on the electromagnetic wave absorption performance of the prepared microsphere MoS 2 @VO 2 composite material. Figure 5 Shows the two-dimensional reflection loss diagrams (8-12 GHz) of VM-(1-3). The loading rates of the fillers are 40%, 50%, and 60% respectively. As Figure 4As shown in d, the electromagnetic wave absorption performances of samples VM-(1-3) in the 8-12 GHz frequency band are -10.92 dB and 1.28 GHz, -56.78 dB and 4.00 GHz, -12.93 dB and 2.08 GHz respectively. The effective absorption bandwidth of VM-2 at a thickness of 3.5 mm covers the entire X-band, and the minimum reflection loss at a thickness of 3.0 mm is -56.78 dB, indicating that VM-2 has a good absorption effect on incident electromagnetic waves within the X-band range of 3.5 mm.

[0061] Figure 6 shows the reflection loss graph of VM-2 at 3.0 mm ( Figure 6 a) and the performance comparison of VM-2 with other research works. It is not difficult to see that compared with single components, the RL min and EAB values have been significantly improved. The comparison results show that constructing the MoS 2 @VO 2 composite material with a core-shell structure semiconductor heterojunction is an effective strategy to endow the absorber with absorption ability in a specific band.

[0062] Generally speaking, the electromagnetic wave absorption performance of an absorber is analyzed and evaluated by the electromagnetic parameters (ε', ε", μ' and μ") of the material. The real part (ε', μ') and the imaginary part (ε", μ") represent the storage and loss capabilities of the absorber for incident electromagnetic waves. As Figure 7 (a, b) shows, the ε' values of the three groups of composite materials increase with the increase of the MoS 2 loading rate, where the ε' value of VM-1 decreases from 4.7 to 4.9, VM-2 from 6.1 to 5.3, and VM-3 from 6.7 to 6.2. Similarly, the ε" value of VM-1 decreases from 1.5 to 1.2, from 1.3 to 1.1, while the value of VM-3 decreases from 1.9 to 1.5. It can be seen that MoS 2 has an obvious effect on improving the electromagnetic loss ability of the material and can effectively adjust the electromagnetic parameters of the material. Combining with the morphological structure of the material, the performance of the VM-2 sample with the most uniform cladding effect is the best. VO 2 The uniform MoS 2 on the surface of the sphere will generate a certain diamagnetic effect under the action of an external electromagnetic field due to its high conductivity, which in turn will cause large fluctuations in the μ' and μ" values of VM-2, deviating them from near 1 and 0. The excessive cladding effect will cause the impedance matching of VM-3 to be unbalanced and the performance to be poor.

[0063] The attenuation constant can be used as an evaluation index for the overall loss ability of the composite material for electromagnetic waves. As Figure 8(As shown in (b), the loss constant value of VM-2 is the highest, far higher than the other two groups of samples, which is consistent with the RL value to a certain extent. Secondly, evaluating the ability of the material to absorb electromagnetic waves requires combination with another important parameter, that is, impedance matching (|Z 0 / Z in |). Combining with Formula 1, the closer the impedance matching value of the absorber is to 1, the more the incident electromagnetic wave can enter the interior of the absorber. It is not difficult to see that in Figure 8 (a), the impedance matching characteristic of VM-2 is also the closest to 1 in the range of 8-12 GHz. It is the synergistic effect of these two that makes VM-2 have good loss ability.

[0064]

[0065] Among them, μ r and ε r are the complex permittivity and complex permeability respectively.

[0066] To analyze the relaxation process caused by the repeated rotation of electric dipoles, it is necessary to introduce Debye theory to explain, and its equation is as follows:

[0067]

[0068] Among them, ε s and ε ∞ represent the static permittivity and the permittivity at infinite frequency respectively. According to the relationship between ε” and ε', a conjugate semicircle can be drawn. The more perfect the semicircle, the more obvious the loss effect caused by the relaxation process of the material, and the tail of the graph represents the dielectric loss ability of the material. VM-2 shows obvious relaxation behavior and dielectric loss ( Figure 9 b), and the existence of the relaxation process in each sample is mainly due to the uneven distribution of charge accumulation and the polarization behavior at the phase interface of the composite material.

[0069] The electromagnetic wave loss mechanism of the MoS 2 @VO 2 composite material with a core-shell structure is as Figure 10 shown. First of all, based on the special core-shell and surface groove structure of the MoS 2 @VO 2 composite material, the incident wave can be scattered at different angles when it contacts the MoS 2 @VO 2 absorber, so as to achieve multiple attenuation. Secondly, at the two-phase contact surface and the sphere contact of MoS 2 @VO 2 , the rough surface of the semiconductor VO 2 sphere can be in contact with MoS 2The outer shells are closely connected, forming a large number of heterojunctions MoS-VO at the formation site of the core-shell structure 2 interfaces. MoS 2 can promote electron transport behavior. After being combined with VO 2 , the impedance matching characteristics of the composite material are improved and the loss ability is enhanced. When electromagnetic waves enter the material, in the core-shell structure MoS 2 @VO 2 composite material, the electrons inside will move directionally to generate current, and then convert the electromagnetic waves into Joule heat. Due to the huge difference in the electron movement rate at the phase interface and the non-coincidence of the positive and negative charge centers, dipole polarization behavior will occur. Therefore, in the core-shell structure MoS 2 @VO 2 composite material, multiple loss mechanisms work together to improve the electromagnetic wave absorption performance of the absorber.

[0070] PEC and MoS 2 @VO 2 composite material's composite model is used for simulation. The RCS value of the model can effectively evaluate the attenuation ability of MoS 2 @VO 2 composite material for electromagnetic waves under far-field conditions. The model consists of an upper absorption layer (thickness: 3 mm) of the composite material and a lower PEC layer (thickness: 1 mm). Its size is 180 mm × 180 mm (for further calculations and details, please refer to the supplementary materials). As Figure 11 (a) shows, compared with the pure PEC plate, the RCS values of the three groups of models have all decreased to varying degrees, and the models show obvious attenuation effects after being coated with the composite material. The specific RCS values in the range of 0°-60° are as Figure 11 (b) shows. The RCS reduction value of VM-2 at 0° is 24.4 dBm 2 , indicating the strongest attenuation effect, which also shows that MoS 2 @VO 2 composite material, under the synergistic effect of multiple losses, can effectively improve the electromagnetic waves of the material, thereby reducing the radar scattering intensity.

Claims

1. Preparation method of core-shell structure MoS 2 @VO 2 composite material It is characterized in that The method steps are as follows: S1: Preparation of hollow VO 2 ; S2: MoS 2 @VO 2 Preparation of composite material S21: Dissolve the hollow VO prepared in S1 2 in deionized water, denoted as mixture A; S22: Dissolve sodium molybdate and thiourea in deionized water, denoted as mixture B; S23: Mix and react the mixture A in S21 and the mixture B in S22; S24: After the reaction, centrifugation, washing, and drying are carried out to obtain MoS 2 @VO 2 composite material.

2. The preparation method of the core-shell structure MoS 2 @VO 2 composite material It is characterized in that The hollow VO 2 is prepared according to the following steps: S11: Dissolve V 2 O 5 and C 2 H 2 O 4 ·2H 2 O in deionized water and denote it as mixture C; S12: Add isopropanol to the mixed solution C for reaction to obtain hollow VO 2 .

3. The preparation method of the core-shell structure MoS 2 @VO 2 composite material It is characterized in that The said V 2 O 5 and C 2 H 2 O 4 ·2H 2 O has a molar ratio of 1:2 - 4.

4. The preparation method of the core-shell structure MoS 2 @VO 2 composite material It is characterized in that In S11, the dissolution temperature is 70 - 90 °C, and the stirring time is 40 - 80 min.

5. The preparation method of the core-shell structure MoS 2 @VO 2 composite material It is characterized in that In S12, the reaction temperature is 180 - 220 °C, and the reaction time is 10 - 14 h.

6. The preparation method of the core-shell structure MoS 2 @VO 2 composite material It is characterized in that Hollow VO 2 The mass ratio of sodium molybdate and thiourea is 1:1 - 15:1 - 15.

7. The preparation method of the core-shell structure MoS 2 @VO 2 composite material It is characterized in that In S23, the reaction temperature is 180 - 220 °C, and the reaction time is 20 - 28 h.

8. The preparation method of the core-shell structure MoS 2 @VO 2 composite material It is characterized in that In S24, the drying temperature is 55 - 65 °C, and the time is 10 - 14 h.

9. A core-shell structure MoS prepared by the method according to any one of claims 1-8 2 @VO 2 composite material.

10. The core-shell structure MoS as described in claim 9 2 @VO 2 Application in electromagnetic wave absorption of the composite material

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