Hollow core-shell MoS2-coated ZnS nanoflower with electromagnetic wave absorption function and preparation method thereof

Abstract

The invention discloses a preparation method of a hollow core-shell MoS2-coated ZnS nanoflower with an electromagnetic wave absorption function, and the preparation method specifically comprises the following steps: dissolving a ZnO nanoflower template and TAA in H2O, and carrying out hydrothermal reaction, centrifugation, washing and drying to obtain a ZnO / ZnS nanoflower; mixing the ZnO / ZnS nanoflowers with a glacial acetic acid solution, stirring, centrifuging, washing and drying to obtain hollow ZnS nanoflowers; and mixing the hollow ZnS nanoflower, Na2MoO4. 2H2O and TA, carrying out hydrothermal reaction, centrifuging, washing and drying to obtain the hollow core-shell MoS2-coated ZnS nanoflower. According to the MoS (at) ZnS nanoflower prepared by the method, the combination of ZnS and MoS optimizes impedance matching through a multi-interface synergistic effect, the electromagnetic wave loss capability of a composite material is remarkably improved, and the MoS (at) ZnS nanoflower shows excellent performance in the field of broadband absorption.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional material preparation, and specifically relates to a preparation method of hollow core-shell MoS2@ZnS nanoflowers with electromagnetic wave absorption function, and also relates to the hollow core-shell MoS2@ZnS nanoflowers. Background Technique

[0002] Dielectric materials, such as ZnS, ZnO, BaTiO3, etc., can cause dielectric loss of electromagnetic waves due to their unique physical and chemical properties. These materials play an important role in electromagnetic wave absorption and shielding technologies, especially in improving the electromagnetic compatibility of materials. However, single-component dielectric materials usually have difficulty in simultaneously possessing good impedance matching and strong electromagnetic attenuation ability, and lack multiple loss mechanisms, making it difficult to achieve broadband absorption. In recent years, researchers have used methods such as chemical deposition and coating to compound conductive materials such as MXene, graphene, MoS2 and magnetic materials such as Fe3O4, Ni, Co with dielectric materials to design composite materials with core-shell structures, hierarchical structures, etc., and then obtain electromagnetic absorbers with strong absorption ability and broadband characteristics. For example, spherical MoS2 was decorated on hollow porous ZnO microspheres to synthesize a ZnO / MoS2 composite material with a hollow shell structure. The absorption bandwidth of this material exceeds -10 dB in the range of 10.24 GHz (from 7.76 GHz to 18 GHz), and the minimum reflection loss (RL) reaches -35.8 dB. Research shows that through the design of composite material structures, the performance of electromagnetic wave absorption materials can be significantly improved, especially showing great potential in terms of strong absorption ability and broadband characteristics, providing an effective solution for electromagnetic compatibility and protection.

[0003] Zinc sulfide (ZnS) has excellent dielectric properties, chemical stability and good mechanical properties, and is widely used in the field of electromagnetic wave absorption. ZnS has different morphological structures such as hollow structures, flower-like shapes, and rod-like shapes. Among them, hollow flower-like ZnS shows significant advantages in the electromagnetic field due to its high specific surface area, low density and high active sites. Its high specific surface area and high active sites provide a rich interface, significantly enhancing the multiple scattering and interfacial polarization effects of electromagnetic waves; the internal hollow structure promotes the multiple reflections of electromagnetic waves, further dissipating the energy of electromagnetic waves, thereby effectively improving the electromagnetic wave absorption performance of the material.

[0004] As an important two-dimensional sheet material, MoS2 has a two-dimensional structure and a direct energy gap similar to those of graphene. Its multi-layered and porous structure can reflect incident electromagnetic waves multiple times, forming rich interfaces, thereby increasing the interfacial polarization effect and significantly improving the electromagnetic wave absorption performance. In addition, MoS2 is easy to combine with other materials to form more heterointerfaces, further optimizing the impedance matching and enhancing the multiple scattering effect, ultimately achieving efficient electromagnetic wave absorption. Summary of the Invention

[0005] The purpose of the present invention is to provide a preparation method of hollow core-shell MoS2@ZnS nanoflowers with electromagnetic wave absorption function, which significantly enhances the dielectric loss and conductive loss capabilities of electromagnetic waves through the core-shell synergistic effect.

[0006] The technical solution adopted by the present invention is a preparation method of hollow core-shell MoS2@ZnS nanoflowers with electromagnetic wave absorption function, which is specifically implemented according to the following steps: Step 1: Prepare a ZnO nanoflower template; Step 2: Dissolve the ZnO nanoflower template and thioacetamide TAA in H2O, stir, and then transfer the solution to a polytetrafluoroethylene autoclave for hydrothermal reaction. After the reaction is completed, collect the precipitate using a centrifuge, wash the precipitate with distilled water and absolute ethanol, and dry it. The obtained product is ZnO / ZnS nanoflowers; Step 3: Mix the ZnO / ZnS nanoflowers with glacial acetic acid solution, stir, collect the precipitate using a centrifuge, wash the precipitate with distilled water and absolute ethanol, and dry it. The obtained product is hollow ZnS nanoflowers; Step 4: Mix the hollow ZnS nanoflowers, Na2MoO4·2H2O, and TA, carry out hydrothermal reaction, centrifuge, wash, and dry to obtain hollow core-shell MoS2@ZnS nanoflowers.

[0007] The characteristics of the present invention also lie in that In Step 1, specifically: Stir H2O and ethanol evenly, then add (CH3COO)2Zn, C2H5NO2, and Na2SO4 and mix them by stirring until completely dissolved. Then add sodium hydroxide and stir to adjust the pH value of the solution. Transfer the uniformly mixed solution to a polytetrafluoroethylene autoclave for hydrothermal reaction. Collect the precipitate using a centrifuge, wash the precipitate with distilled water and absolute ethanol, dry it, and calcine it. The obtained product is the ZnO nanoflower template.

[0008] The hydrothermal reaction temperature is 150 - 200 °C, and the reaction time is 6 - 14 h; the calcination temperature is 400 - 600 °C, and the calcination time is 1 - 4 h.

[0009] In Step 2, the stirring time is 0.5 - 2 h, the hydrothermal reaction temperature is 80 - 110 °C, and the hydrothermal reaction time is 6 - 12 h.

[0010] In Step 3, the mass fraction of the glacial acetic acid solution is 5 - 20%; the stirring time is 0.5 - 2 h.

[0011] In Step 4, specifically: ZnS nanoflowers and H2O are blended and stirred evenly, Na2MoO4·2H2O and TAA are added, stirred, and the mixed solution is transferred to a polytetrafluoroethylene high-pressure reaction kettle for hydrothermal reaction. The precipitate is collected by a centrifuge, washed with distilled water and absolute ethanol, and dried. The obtained product is the hollow core-shell MoS2@ZnS nanoflowers.

[0012] The hydrothermal reaction temperature is 150 - 180 °C, and the hydrothermal reaction time is 10 - 14 h.

[0013] The beneficial effects of the present invention are as follows: The flower-like MoS2@ZnS nanoflowers with a hollow core-shell structure prepared by the present invention can significantly improve the absorption efficiency through multiple reflections of electromagnetic waves due to their unique hollow cavity and core-shell structure. In addition, the high specific surface area and low density characteristics of the hollow porous structure provide ideal conditions for multiple scattering and energy dissipation of electromagnetic waves. The flower-like structure of ZnS and MoS2 forms a rich heterointerface, and the electromagnetic wave energy is effectively consumed through loss mechanisms such as interfacial polarization and dipole polarization. The combination of ZnS and MoS2 optimizes the impedance matching through a multiple interface synergistic effect, significantly improving the electromagnetic wave loss ability of the composite material and showing excellent performance in the field of broadband absorption. Description of the Drawings

[0014] Figure 1 is the SEM photograph of Example 1; Figure 2 is the SEM photograph of the hollow core-shell MoS2@ZnS nanoflowers prepared in Example 1; Figure 3 is the EDS analysis diagram of S element in the hollow core-shell MoS2@ZnS nanoflowers prepared in Example 1; Figure 4 is the EDS analysis diagram of Zn element in the hollow core-shell MoS2@ZnS nanoflowers prepared in Example 1; Figure 5 is the EDS analysis diagram of Mo element in the hollow core-shell MoS2@ZnS nanoflowers prepared in Example 1; Figure 6 is the XRD spectrum of the hollow core-shell MoS2@ZnS nanoflowers prepared in Example 1. Detailed Embodiments

[0015] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0016] A preparation method of hollow core-shell MoS2@ZnS nanoflowers with electromagnetic wave absorption function according to the present invention is specifically implemented according to the following steps: Step 1: Prepare a ZnO nanoflower template; 15 - 20 mL of H2O and 10 - 20 mL of ethanol are stirred evenly and then 0.2 - 1 g of (CH3COO)2Zn, 0.2 - 0.6 g of C2H5NO2, and 0.1 - 0.5 g of Na2SO4 are added and stirred until completely dissolved. Then 0.4 - 1 g of sodium hydroxide NaOH is added, and magnetic stirring is carried out for 1 h to adjust the pH value of the solution. The uniformly mixed solution is transferred to a polytetrafluoroethylene autoclave for hydrothermal reaction. The hydrothermal reaction temperature is 150 - 200 °C, and the reaction time is 6 - 14 h. After the reaction is completed, the precipitate is collected by a centrifuge, and the precipitate is washed repeatedly with distilled water and absolute ethanol to remove impurities. Then the washed precipitate is dried at 80 °C for 12 h, and finally the dried precipitate is calcined at 400 - 600 °C for 1 - 4 h. The obtained product is the ZnO nanoflower template.

[0017] Step 2: Prepare ZnO / ZnS nanoflowers; 0.1 - 0.5 g of ZnO nanoflower template and 0.5 - 2 g of thioacetamide TAA are dissolved in 20 - 100 mL of H2O, and stirred for 0.5 - 2 h until completely dissolved. Then the solution is transferred to a polytetrafluoroethylene autoclave for hydrothermal reaction. The hydrothermal reaction temperature is 80 - 110 °C, and the reaction time is 6 - 12 h. After the reaction is completed, the precipitate is collected by a centrifuge, and the precipitate is washed repeatedly with distilled water and absolute ethanol to remove impurities. Finally, the washed precipitate is dried at 60 °C for 6 h. The obtained product is the ZnO / ZnS nanoflower; Step 3: Prepare hollow ZnS nanoflowers; 0.2 - 1.2 g of ZnO / ZnS nanoflowers are mixed with an acetic acid solution with a mass fraction of 5 - 20%, and magnetic stirring is carried out for 0.5 - 2 h. Then the precipitate is collected by a centrifuge, and the precipitate is washed repeatedly with distilled water and absolute ethanol to remove impurities. Finally, the washed precipitate is dried at 60 °C for 6 h. The obtained product is the hollow ZnS nanoflower; Step 4: Prepare hollow core-shell MoS2@ZnS nanoflowers; 0.1 - 0.5 g of ZnS nanoflowers were blended and stirred evenly with 120 mL of H2O, 0.2 - 0.6 g of Na2MoO4·2H2O and 0.1 - 0.4 g of TAA were added, and they were blended and stirred for 0.5 - 2 h. Secondly, the mixed solution was transferred to a polytetrafluoroethylene high-pressure reactor for hydrothermal reaction. The hydrothermal reaction temperature was 150 - 180 °C, and the hydrothermal reaction time was 10 - 14 h. After the reaction, the precipitate was collected using a centrifuge, and the precipitate was washed multiple times with distilled water and absolute ethanol to remove impurities. Finally, the washed precipitate was dried at 60 °C for 6 h, and the obtained product was the hollow core-shell MoS2@ZnS nanoflowers.

[0018] For the hollow core-shell MoS2@ZnS nanoflowers of the present invention, the hollow ZnS nanoflowers with excellent dielectric properties and chemical stability are used as the core, and MoS2 with a layered structure and rich interfaces is used as the shell. Through the core-shell synergistic effect, the dielectric loss and conductive loss capabilities of electromagnetic waves are significantly enhanced. The hollow ZnS nanoflowers provide rich interfacial polarization effects and multiple reflections, and the layered structure of MoS2 further enhances the multiple scattering and interfacial polarization effects, while improving the mechanical properties and wave absorption stability of the material. Through the core-shell structure design, the synergistic effect of dielectric loss and conductive loss is realized, significantly improving the electromagnetic wave absorption performance, and having excellent mechanical properties and wave absorption stability.

[0019] Example 1 The preparation method of the hollow core-shell MoS2@ZnS nanoflowers with electromagnetic wave absorption function of the present invention is specifically as follows: Step 1: Preparation of ZnO nanoflower template: First, 15 mL of H2O and 15 mL of ethanol were weighed and stirred evenly, then 0.5 g of (CH3COO)2Zn, 0.4 g of C2H5NO2, and 0.3 g of Na2SO4 were added and blended and stirred until completely dissolved. Secondly, 0.6 g of NaOH was weighed and magnetically stirred for 1 h to adjust the pH value of the solution. The homogeneous solution was transferred to a polytetrafluoroethylene high-pressure reactor and reacted at 180 °C for 10 h. Then, after the reaction, the precipitate was collected using a centrifuge, and the precipitate was washed multiple times with distilled water and absolute ethanol to remove impurities. Then, the washed precipitate was dried at 80 °C for 12 h. Finally, the dried precipitate was calcined at 400 °C for 2 h, and the obtained product was the ZnO nanoflower template.

[0020] Step 2: Preparation of ZnO / ZnS nanoflowers First, weigh 0.4 g of ZnO nanoflower templates and 0.4 g of thioacetamide (TAA) and dissolve them in 50 mL of H2O. Stir for 1 h to ensure complete dissolution. Secondly, transfer the solution to a polytetrafluoroethylene autoclave and react at 90 °C for 11 h. After the reaction, use a centrifuge to collect the precipitate, and wash the precipitate with distilled water and anhydrous ethanol multiple times to remove impurities. Finally, dry the washed precipitate at 60 °C for 6 h. The obtained product is ZnO / ZnS nanoflowers.

[0021] Step 3: Preparation of hollow ZnS nanoflowers First, weigh 0.5 g of ZnO / ZnS nanoflowers and a 5% mass fraction of glacial acetic acid solution and stir magnetically for 2 h. Then, use a centrifuge to collect the precipitate, and wash the precipitate with distilled water and anhydrous ethanol multiple times to remove impurities. Finally, dry the washed precipitate at 60 °C for 6 h. The obtained product is hollow ZnS nanoflowers.

[0022] Step 4: Preparation of hollow core-shell MoS2@ZnS nanoflowers First, weigh 0.2 g of ZnS nanoflowers and mix them evenly with 120 mL of H2O. Add 0.3 g of Na2MoO4·2H2O and 0.2 g of TAA, and mix and stir for 1 h. Secondly, transfer the solution to a polytetrafluoroethylene autoclave and react at 180 °C for 14 h. After the reaction, use a centrifuge to collect the precipitate, and wash the precipitate with distilled water and anhydrous ethanol multiple times to remove impurities. Finally, dry the washed precipitate at 60 °C for 6 h. The obtained product is hollow core-shell MoS2@ZnS nanoflowers.

[0023] Example 2 The preparation method of hollow core-shell MoS2@ZnS nanoflowers with electromagnetic wave absorption function in the present invention is specifically as follows: Step 1: Preparation of ZnO nanoflower templates: First, weigh 18 mL of H2O and 15 mL of ethanol, stir evenly, and then add 0.5 g of (CH3COO)2Zn, 0.23 g of C2H5NO2, and 0.2 g of Na2SO4, and mix and stir until completely dissolved. Secondly, weigh 0.4 g of NaOH and stir magnetically for 1 h to adjust the pH value of the solution. Transfer the solution to a polytetrafluoroethylene autoclave and react at 180 °C for 12 h. After the reaction, use a centrifuge to collect the precipitate, and wash the precipitate with distilled water and anhydrous ethanol multiple times to remove impurities. Then, dry the washed precipitate at 80 °C for 12 h. Finally, calcine the dried precipitate at 400 °C for 4 h. The obtained product is ZnO nanoflower templates.

[0024] Step 2: Preparation of ZnO / ZnS nanoflowers First, weigh 0.3 g of ZnO nanoflower templates and 1 g of thioacetamide (TAA) and dissolve them in 50 mL of H2O, then stir for 1.5 h to ensure complete dissolution. Secondly, transfer the solution to a polytetrafluoroethylene autoclave and react at 100 °C for 10 h. After the reaction, use a centrifuge to collect the precipitate, and wash the precipitate with distilled water and anhydrous ethanol multiple times to remove impurities. Finally, dry the washed precipitate at 60 °C for 6 h. The obtained product is ZnO / ZnS nanoflowers.

[0025] Step 3: Preparation of hollow ZnS nanoflowers First, weigh 0.4 ZnO / ZnS nanoflowers and a 10% mass fraction of glacial acetic acid solution, and stir magnetically for 1 h. Then use a centrifuge to collect the precipitate, wash the precipitate with distilled water and anhydrous ethanol multiple times to remove impurities. Finally, dry the washed precipitate at 60 °C for 6 h. The obtained product is hollow ZnS nanoflowers.

[0026] Step 4: Preparation of hollow core-shell MoS2@ZnS nanoflowers First, weigh 0.5 g of ZnS nanoflowers and mix them evenly with 120 mL of H2O, add 0.5 g of Na2MoO4·2H2O and 0.3 g of TAA, and mix and stir for 2 h. Secondly, transfer the solution to a polytetrafluoroethylene autoclave and react at 180 °C for 14 h. After the reaction, use a centrifuge to collect the precipitate, wash the precipitate with distilled water and anhydrous ethanol multiple times to remove impurities. Finally, dry the washed precipitate at 60 °C for 6 h. The obtained product is hollow core-shell MoS2@ZnS nanoflowers.

[0027] Example 3 The preparation method of hollow core-shell MoS2@ZnS nanoflowers with electromagnetic wave absorption function in the present invention is specifically as follows: Step 1: Preparation of ZnO nanoflower templates: First, weigh 18 mL of H2O and 15 mL of ethanol, stir evenly, then add 0.5 g of (CH3COO)2Zn, 0.23 g of C2H5NO2, and 0.2 g of Na2SO4, and mix and stir until completely dissolved. Secondly, weigh 0.4 g of NaOH and stir magnetically for 1 h to adjust the pH value of the solution. Transfer the solution to a polytetrafluoroethylene autoclave and react at 180 °C for 12 h. After the reaction, use a centrifuge to collect the precipitate, wash the precipitate with distilled water and anhydrous ethanol multiple times to remove impurities, and then dry the washed precipitate at 80 °C for 12 h. Finally, calcine the dried precipitate at 400 °C for 4 h. The obtained product is ZnO nanoflower templates.

[0028] Step 2: Preparation of ZnO / ZnS nanoflowers First, weigh 0.3 g of ZnO nanoflower templates and 1 g of TAA, dissolve them in 50 mL of H2O, and stir for 1.5 h to ensure complete dissolution. Secondly, transfer the solution to a polytetrafluoroethylene autoclave and react at 100 °C for 10 h. Then, after the reaction, use a centrifuge to collect the precipitate, wash the precipitate with distilled water and anhydrous ethanol multiple times to remove impurities. Finally, dry the washed precipitate at 60 °C for 6 h. The obtained product is ZnO / ZnS nanoflowers.

[0029] Step 3: Preparation of hollow ZnS nanoflowers First, weigh 0.4 ZnO / ZnS nanoflowers and a 10% mass fraction of glacial acetic acid solution, stir magnetically for 1 h, then use a centrifuge to collect the precipitate, wash the precipitate with distilled water and anhydrous ethanol multiple times to remove impurities. Finally, dry the washed precipitate at 60 °C for 6 h. The obtained product is hollow ZnS nanoflowers.

[0030] Step 4: Preparation of hollow core-shell MoS2@ZnS nanoflowers First, weigh 0.5 g of ZnS nanoflowers and mix them evenly with 120 mL of H2O, add 0.5 g of Na2MoO4·2H2O and 0.3 g of TAA, and mix and stir for 2 h. Secondly, transfer the solution to a polytetrafluoroethylene autoclave and react at 180 °C for 14 h. Then, after the reaction, use a centrifuge to collect the precipitate, wash the precipitate with distilled water and anhydrous ethanol multiple times to remove impurities. Finally, dry the washed precipitate at 60 °C for 6 h. The obtained product is hollow core-shell MoS2@ZnS nanoflowers.

[0031] Example 4 The preparation method of hollow core-shell MoS2@ZnS nanoflowers with electromagnetic wave absorption function in the present invention is specifically as follows: Step 1: Preparation of ZnO nanoflower templates: First, weigh 18 mL of H2O and 12 mL of ethanol, stir evenly, add 0.5 g of (CH3COO)2Zn, 0.3 g of C2H5NO2, and 0.4 g of Na2SO4, and mix and stir until completely dissolved. Secondly, weigh 0.6 g of NaOH, stir magnetically for 1 h to adjust the pH value of the solution, transfer the solution to a polytetrafluoroethylene autoclave, and react at 200 °C for 10 h. Then, after the reaction, use a centrifuge to collect the precipitate, wash the precipitate with distilled water and anhydrous ethanol multiple times to remove impurities, and then dry the washed precipitate at 80 °C for 12 h. Finally, calcine the dried precipitate at 300 °C for 1 - 4 h. The obtained product is ZnO nanoflower templates.

[0032] Step 2: Preparation of ZnO / ZnS nanoflowers First, weigh 0.4 g of ZnO nanoflower templates and 1.5 g of TAA, dissolve them in 50 mL of H2O, and stir for 1 h to ensure complete dissolution. Secondly, transfer the homogeneous solution to a polytetrafluoroethylene autoclave and react at 100 °C for 10 h. Then, after the reaction is completed, use a centrifuge to collect the precipitate, and wash the precipitate with distilled water and anhydrous ethanol multiple times to remove impurities. Finally, dry the washed precipitate at 60 °C for 6 h. The obtained product is ZnO / ZnS nanoflowers.

[0033] Step 3: Preparation of hollow ZnS nanoflowers First, weigh 0.3 g of ZnO / ZnS nanoflowers and 10% glacial acetic acid solution, stir strongly for 1 h, then use a centrifuge to collect the precipitate, wash the precipitate with distilled water and anhydrous ethanol multiple times to remove impurities, and finally dry the washed precipitate at 60 °C for 6 h. The obtained product is hollow ZnS nanoflowers.

[0034] Step 4: Preparation of hollow core-shell MoS2@ZnS nanoflowers First, weigh 0.3 g of ZnS nanoflowers and mix them evenly with 120 mL of H2O, add 0.5 g of Na2MoO4·2H2O and 0.3 g of TAA, and mix and stir for 1 h. Secondly, transfer the solution to a polytetrafluoroethylene autoclave and react at 180 °C for 12 h. Then, after the reaction is completed, use a centrifuge to collect the precipitate, wash the precipitate with distilled water and anhydrous ethanol multiple times to remove impurities, and finally dry the washed precipitate at 60 °C for 6 h. The obtained product is hollow core-shell MoS2@ZnS nanoflowers.

[0035] Example 5 Figure 1 The ZnS nanoflowers prepared in Example 1 presented a typical three-dimensional flower-like structure. Its surface was constructed by cross-linked nanosheets to form a porous surface, and a clear hollow cavity structure was visible inside. After MoS2 coating by hydrothermal method, as Figure 2 shown, the obtained MoS2@ZnS nanoparticles still maintained a complete flower-like morphology, and a significant hierarchical structure was observed at the core-shell interface, confirming that MoS2 was successfully coated on the surface of ZnS nanoflowers.

[0036] Example 6 Through energy-dispersive X-ray spectroscopy (EDS) elemental distribution analysis ( Figure 3 , Figure 4 , Figure 5 ), it can be seen that the three elements of S, Zn, and Mo showed a uniform spatial distribution characteristic in the sample. Among them, the characteristic signal of the Mo element completely covered the Zn element distribution area, further verifying that a complete coating layer of MoS2 was formed on the surface of ZnS nanoflowers.

[0037] Figure 6 XRD spectrum analysis shows that the diffraction peaks of the composite material are composed of two phases, ZnS and MoS2. The characteristic peak at 2θ = 14.2° corresponds to the (002) crystal plane of hexagonal MoS2, while the three diffraction peaks at 28.5°, 47.5° and 56.7° correspond to the (111), (220) and (311) crystal planes of cubic ZnS, respectively. It is worth noting that no other impurity phase diffraction peaks were detected, indicating that the hollow MoS2@ZnS nanoflowers with a clear core-shell structure were successfully prepared.

[0038] For the hollow MoS2@ZnS nanoflowers of the present invention, the ZnS in the core layer has excellent dielectric properties and can effectively enhance impedance matching. The MoS2 in the shell layer has advantages such as a layered structure, tunable bandgap and large specific surface area, and can dissipate electromagnetic waves through methods such as interfacial polarization. In addition, the internal hollow structure can enhance the multiple reflections of electromagnetic waves, thereby improving the loss performance of electromagnetic waves. The hollow core-shell MoS2@ZnS nanoflowers have strong absorption and wide bandwidth, and are expected to be widely used in the fields of electromagnetic functional materials, electrochemistry, etc.

Claims

1. A method for preparing hollow core-shell MoS2@ZnS nanoflowers with electromagnetic wave absorption function, characterized in that: Follow the steps below to implement it: Step 1: Prepare ZnO nanoflower template; Step 2: Dissolve the ZnO nanoflower template and thioacetamide TAA in H2O, stir, and then transfer the solution to a polytetrafluoroethylene high-pressure reactor for hydrothermal reaction. After the reaction is completed, use a centrifuge to collect the precipitate, wash the precipitate with distilled water and anhydrous ethanol, and dry it. The resulting product is ZnO / ZnS nanoflower; Step 3: Mix the ZnO / ZnS nanoflowers with the glacial acetic acid solution, stir, collect the precipitate with a centrifuge, wash the precipitate with distilled water and anhydrous ethanol, and dry, and the obtained product is the hollow ZnS nanoflower; Step 4: The hollow ZnS nanoflowers, Na2MoO4·2H2O and TA are mixed, subjected to hydrothermal reaction, centrifuged, washed and dried to obtain hollow core-shell MoS2@ZnS nanoflowers.

2. The method for preparing the hollow core-shell MoS2@ZnS nanoflower with electromagnetic wave absorption function as claimed in claim 1, characterized in that: In the step 1, specifically: After H2O and ethanol are stirred evenly, (CH3COO)2Zn, C2H5NO2, and Na2SO4 are added and mixed and stirred until completely dissolved, and then sodium hydroxide is added and stirred. The mixed solution is transferred to a polytetrafluoroethylene high-pressure reactor for hydrothermal reaction, and the precipitate is collected by a centrifuge, washed with distilled water and anhydrous ethanol, dried, and calcined. The obtained product is a ZnO nanoflower template.

3. The method for preparing the hollow core-shell MoS2@ZnS nanoflower with electromagnetic wave absorption function as claimed in claim 2, characterized in that: The hydrothermal reaction temperature is 150-200°C, and the reaction time is 6-14h; the calcination temperature is 400-600°C, and the calcination time is 1-4h.

4. The method for preparing the hollow core-shell MoS2@ZnS nanoflower with electromagnetic wave absorption function as claimed in claim 1, characterized in that: In the step 2, the stirring time is 0.5-2 h, the hydrothermal reaction temperature is 80-110° C., and the hydrothermal reaction time is 6-12 h.

5. The method for preparing the hollow core-shell MoS2@ZnS nanoflower with electromagnetic wave absorption function as claimed in claim 1, characterized in that: In step 3, the mass fraction of the glacial acetic acid solution is 5-20%; and the stirring time is 0.5-2 h.

6. The method for preparing the hollow core-shell MoS2@ZnS nanoflower with electromagnetic wave absorption function as claimed in claim 1, characterized in that: In the step 4, specifically: The ZnS nanoflowers were mixed with H2O and stirred evenly, Na2MoO4·2H2O and TAA were added and stirred, and the mixed solution was transferred to a polytetrafluoroethylene high-pressure reactor for hydrothermal reaction, and the precipitate was collected by a centrifuge, washed with distilled water and anhydrous ethanol, and dried to obtain the hollow core-shell MoS2@ZnS nanoflowers.

7. The method for preparing the hollow core-shell MoS2@ZnS nanoflower with electromagnetic wave absorption function as claimed in claim 6, characterized in that: The hydrothermal reaction temperature is 150-180°C, and the hydrothermal reaction time is 10-14 h.

8. The hollow core-shell MoS2@ZnS nanoflowers prepared by the method for preparing the hollow core-shell MoS2@ZnS nanoflowers with electromagnetic wave absorption function as described in any one of claims 1 to 7.

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