MoS2-coated FeCoSe / rGO aerogel composite material and preparation method thereof

Abstract

The invention discloses a preparation method of a MoS2-coated FeCoSe / rGO aerogel composite material. The preparation method specifically comprises the following steps: preparing rGO powder through an improved Hummer method; feCoSe powder is prepared through a hydrothermal method; the preparation method comprises the following steps: adding FeCoSe powder, Na2MoO4. 2H2O and thioacetamide powder into deionized water, stirring, carrying out a hydrothermal reaction, carrying out centrifugal washing, and drying to obtain MoS2-coated FeCoSe powder; a hydrothermal method and a freeze-drying technology are used for preparing the MoS2-coated FeCoSe / rGO aerogel composite material. According to the method disclosed by the invention, through the design of the three-dimensional porous aerogel, the high loss characteristic is realized by introducing the composite filler, and the composite material with high electromagnetic wave absorption is prepared; meanwhile, the preparation method is simple, convenient and feasible, has lower production cost and is easy for batch production.

Description

Technical Field

[0001] This invention belongs to the field of composite material preparation technology, specifically relating to a method for preparing MoS2@FeCoSe / rGO aerogel composite material, and also relating to the MoS2@FeCoSe / rGO aerogel composite material. Background Technology

[0002] With the rapid development of 5G communication and military stealth technology, the demand for high-performance electromagnetic wave absorbing materials is increasing. These materials need to be lightweight, have a wide bandwidth, and good impedance matching characteristics. However, conventional absorbing materials are no longer suitable for current application requirements due to limitations such as high density, narrow operating bandwidth, and poor impedance matching. Developing new, high-efficiency electromagnetic wave absorbing materials has become the key to solving these problems.

[0003] Studies have shown that single-component materials generally suffer from problems such as imperfect impedance matching and insufficient absorption performance. Using multi-component composite material systems can effectively adjust the balance between magnetic and dielectric losses, thereby optimizing impedance matching characteristics. Furthermore, by introducing interfacial polarization effects and constructing defect structures, the polarization loss mechanism of the material can be significantly enhanced, thus extending its effective absorption bandwidth.

[0004] MoS2 possesses a two-dimensional layered structure, providing numerous interfacial polarization sites, and its semiconductor properties allow for tuning of dielectric properties. It combines with FeCoSe to form a heterojunction, promoting interfacial charge transfer and enhancing dielectric loss. Simultaneously, the Fe / Co bimetallic combination synergistically improves permeability, while Se doping modulates the electronic structure and increases magnetic anisotropy. rGO, acting as a three-dimensional conductive network, enhances conductivity loss, while loading MoS2 and FeCoSe prevents aggregation. The surface functional groups (-OH, -COOH) of rGO provide active sites, optimizing dispersibility and interfacial bonding. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing MoS2@FeCoSe / rGO aerogel composite materials, which solves the problem of low electromagnetic wave absorption performance of composite materials in the prior art.

[0006] Another object of the present invention is to provide the above-mentioned MoS2@FeCoSe / rGO aerogel composite material.

[0007] The technical solution adopted in this invention is a method for preparing MoS2@FeCoSe / rGO aerogel composite material, which is implemented according to the following steps: Step 1: Prepare rGO powder using the modified Hummer method; Step 2: Prepare FeCoSe powder by hydrothermal method; Step 3: Add FeCoSe powder, Na2MoO4·2H2O and thioacetamide powder to deionized water, stir to obtain a mixed solution, transfer the mixed solution to a high-pressure reactor for hydrothermal reaction, centrifuge, wash and dry to obtain MoS2@FeCoSe powder; Step 4: Following step 3, MoS2@FeCoSe / rGO aerogel composite material is prepared using a hydrothermal method and freeze-drying technology.

[0008] The invention is further characterized in that, In step 1, the specific steps are as follows: Step 1.1: Under oil bath conditions of 70-90℃, P2O5, K2S2O8 and graphite are dissolved in sulfuric acid and stirred for 5-7 hours until they are mixed evenly. The mixture is then vacuum filtered to collect the precipitate. Under ice bath conditions of 3-5℃, the precipitate is dissolved in sulfuric acid and potassium permanganate is added in batches. After each addition, the mixture is stirred for 1-3 hours until it is mixed evenly to obtain a mixed solution. Step 1.2: Add deionized water and H2O2 to the mixture from Step 1.1, then add dilute hydrochloric acid and let stand for 12-24 hours; take the lower layer of the mixture and dialyze it in water. After dialyzing, stir for 3-5 hours at a stirring rate of 2000-3000 r / min to obtain a GO dispersion. Step 1.3: Pre-cool the obtained GO dispersion and then freeze-dry it to obtain rGO powder.

[0009] In step 1.1, the mass ratio of P2O5, K2S2O8, and graphite is 0.5-1.5:0.5-1.5:0.25-1.35; in step 1.3, the pre-cooling temperature is -21 to -31℃, and the pre-cooling time is 30-60 min; the freeze-drying temperature is -30 to -40℃, and the freeze-drying time is 48-72 h.

[0010] Step 2 specifically involves: Co(NO3)2·6H2O, Fe(NO3)3·9H2O, selenium powder, and NaBH4 powder were added to deionized water and stirred for 20-30 min to obtain a mixed solution. The mixed solution was transferred to a high-pressure reactor for hydrothermal reaction. After cooling, the precipitate was collected, centrifuged, washed, and dried to obtain FeCoSe powder. The hydrothermal reaction temperature was 170-180℃, and the hydrothermal reaction time was 11-13 h. The mass ratio of Co(NO3)2·6H2O, Fe(NO3)3·9H2O, selenium powder, NaBH4, and deionized water was 0.5-1.5:0.36-1.78:0.58-3.56:0.13-0.39:3.42-4.78.

[0011] In step 3, the mass ratio of FeCoSe powder, Na2MoO4·2H2O, thioacetamide, and deionized water is 0.5-1.5:0.29-0.97:0.12-0.63:3.42-4.78; the reaction temperature is 190-210℃; the reaction time is 23-25h; and the stirring time is 20-30min.

[0012] Step 4 specifically involves: Step 4.1: Add rGO powder and MoS2@FeCoSe powder to deionized water, stir to obtain a mixed solution, transfer the mixed solution to a high-pressure reactor for hydrothermal reaction, cool naturally to room temperature, and soak the obtained aerogel in a mixed solution of water and ethanol for 24-48 hours for hydrolysis. Step 4.2: Pre-cool the aerogel obtained in step 4.1, and then freeze-dry it to obtain MoS2@FeCoSe / rGO aerogel.

[0013] In step 4.1, the reaction temperature is 170-190℃ and the reaction time is 9-11h; the mass ratio of rGO powder, MoS2@FeCoSe powder and deionized water is 0.5-1.5:0.5-1.5:1.5-4.5.

[0014] In step 4.2, the pre-cooling temperature is -21 to -31℃ and the pre-cooling time is 30 to 60 minutes; the freeze-drying temperature is -30 to -40℃ and the freeze-drying time is 48 to 72 hours.

[0015] Another technical solution adopted in this invention is a composite material prepared by a method for preparing MoS2@FeCoSe / rGO aerogel composite material.

[0016] The beneficial effects of this invention are: The method of this invention achieves high loss characteristics by introducing composite fillers through the design of three-dimensional porous aerogels, and prepares composite materials with high electromagnetic wave absorption. At the same time, the preparation method is simple and feasible, has low production cost, and is easy to mass-produce. Attached Figure Description

[0017] Figure 1 This is a morphology diagram (I) of the MoS2@FeCoSe / rGO aerogel composite material of Example 5; Figure 2 This is a morphology diagram (II) of the MoS2@FeCoSe / rGO aerogel composite material from Example 5. Figure 3 This is an XPS image of the MoS2@FeCoSe / rGO aerogel composite material from Example 5.

[0018] Figure 4 This is a graph showing the electromagnetic wave absorption performance of the pure rGO aerogel in Example 1; Figure 5 The electromagnetic properties of the FeCo-MOF / rGO aerogel composite material in Example 2 Wave absorption performance diagram; Figure 6 This is a graph showing the electromagnetic wave absorption performance of the FeCoSe / rGO aerogel composite material in Example 3; Figure 7 This is a graph showing the electromagnetic wave absorption performance of the MoS2 / rGO aerogel composite material in Example 4; Figure 8 This is a graph showing the electromagnetic wave absorption performance of the MoS2@FeCoSe / rGO aerogel composite material in Example 5. Detailed Implementation

[0019] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0020] The preparation method of the MoS2@FeCoSe / rGO aerogel composite material of the present invention is carried out according to the following steps: Step 1: Prepare rGO powder using the improved Hummer method; the specific steps are as follows: Step 1.1: Under oil bath conditions of 70-90℃, dissolve phosphorus pentoxide (P2O5), potassium persulfate (K2S2O8), and graphite in sulfuric acid, stir for 5-7 hours, mix evenly, vacuum filter, collect the precipitate, dissolve the precipitate in sulfuric acid under ice bath conditions of 3-5℃, add potassium permanganate (KMnO4) in batches, stir for 1-3 hours after each addition, mix evenly to obtain a mixed solution; The mass ratio of P2O5, K2S2O8, and graphite is 0.5-1.5:0.5-1.5:0.25-1.35. Step 1.2: Add deionized water and hydrogen peroxide (H2O2) to the mixture from Step 1.1 to remove KMnO4. Then, add the solution to dilute hydrochloric acid and let it stand for 12-24 hours. Take the lower layer of the mixture and dialyze it in water for 48-72 hours. After dialyzing, stir the solution at high speed for 3-5 hours at a stirring rate of 2000-3000 r / min to obtain a GO dispersion. Step 1.3: Pre-cool the obtained GO dispersion and then freeze-dry it to obtain rGO powder; The pre-cooling temperature is -21 to -31℃, and the pre-cooling time is 30-60 minutes; The freeze-drying temperature is -30 to -40℃, and the freeze-drying time is 48-72 hours. Step 2: Prepare FeCoSe powder using a hydrothermal method; specifically: Co(NO3)2·6H2O, Fe(NO3)3·9H2O, selenium powder, and NaBH4 powder were added to deionized water and stirred for 20-30 min to obtain a mixed solution. The mixed solution was then transferred to a high-pressure reactor for hydrothermal reaction at a temperature of 170-180℃ for 11-13 h. The mixture was then allowed to cool naturally to room temperature, the precipitate was collected, centrifuged and washed at a speed of 8000 r / min, and dried to obtain FeCoSe powder. The mass ratio of Co(NO3)2·6H2O, Fe(NO3)3·9H2O, selenium powder, NaBH4, and deionized water is 0.5-1.5:0.36-1.78:0.58-3.56:0.13-0.39:3.42-4.78. Step 3: Following step 2, MoS2@FeCoSe powder is prepared; specifically: Add the FeCoSe powder, Na2MoO4·2H2O, and thioacetamide powder from the above steps to deionized water and stir for 20-30 minutes to obtain a mixed solution. Transfer the mixed solution to a high-pressure reactor for hydrothermal reaction. After the reaction is completed and cooled to room temperature, collect the precipitate, centrifuge and wash it several times, and dry it to obtain MoS2@FeCoSe powder.

[0021] The reaction temperature is 190-210℃, and the reaction time is 23-25h; The mass ratio of FeCoSe powder, Na2MoO4·2H2O, thioacetamide, and deionized water is 0.5-1.5:0.29-0.97:0.12-0.63:3.42-4.78. Step 4: Following step 3, the MoS2@FeCoSe / rGO aerogel composite material is prepared using freeze-drying technology; specifically: Step 4.1: Add rGO powder and MoS2@FeCoSe powder to deionized water and stir to obtain a mixed solution. Transfer the mixed solution to a high-pressure reactor for hydrothermal reaction at a temperature of 170-190℃ for 9-11 hours. Allow it to cool naturally to room temperature and then soak the resulting aerogel in a mixed solution of water and ethanol for 24-48 hours to hydrolyze it and remove excess ions. The mass ratio of water to ethanol is 9-11:0.5-1.5; The mass ratio of rGO powder, MoS2@FeCoSe powder, and deionized water is 0.5-1.5:0.5-1.5:1.5-4.5. Step 4.2: Pre-cool the aerogel obtained in step 4.1, and then freeze-dry it to obtain MoS2@FeCoSe / rGO aerogel.

[0022] The pre-cooling temperature is -21 to -31℃, and the pre-cooling time is 30-60 minutes; The freeze-drying temperature is -30 to -40℃, and the freeze-drying time is 48-72 hours.

[0023] The MoS2@FeCoSe / rGO composite electromagnetic wave absorbing material prepared by the method of this invention achieves efficient electromagnetic wave absorption through the synergistic effect of multiple components and optimized impedance matching. Its mechanism of action is mainly reflected in the following aspects: First, MoS2 and rGO provide dielectric loss, dissipating electromagnetic energy through interface polarization, dipole polarization, and conductivity loss mechanisms; second, FeCoSe nanoparticles contribute magnetic loss, including natural resonance, domain wall resonance, and optimized eddy current loss; third, the three-dimensional network structure of rGO and MoS2@FeCoSe form multiple reflection channels, extending the electromagnetic wave propagation path. Simultaneously, the synergistic regulation of each component achieves a good balance between the complex permittivity and complex permeability of the material, significantly improving impedance matching and reducing electromagnetic wave reflection. Furthermore, heterojunctional interface polarization, Se doping-induced defect engineering, and nanostructure regulation jointly enhance the material's polarization loss capability and environmental stability.

[0024] This invention utilizes a hydrothermal method and a freeze-drying method to prepare a MoS2@FeCoSe / rGO aerogel composite material with high electromagnetic wave absorption performance. The preparation process is simple and low-cost, and has wide applicability and promotion value. Moreover, the MoS2@FeCoSe / rGO aerogel composite material has excellent electromagnetic wave absorption performance, which can meet the application requirements of aerospace, thermal insulation, sensing and other fields.

[0025] Example 1 The specific steps for preparing pure rGO aerogel are as follows: Step 1: Prepare GO powder using the improved Hummer method. The specific steps are as follows: Step 1.1: Under oil bath conditions, dissolve phosphorus pentoxide (P2O5), potassium persulfate (K2S2O8), and graphite in sulfuric acid. Stir for 6 hours until homogeneous. The mass ratio of P2O5, K2S2O8, and graphite is 1:1:0.75.

[0026] Step 1.2: Vacuum filter the mixture and collect the precipitate. Dissolve the mixture in sulfuric acid under ice bath conditions, adding 9g of potassium permanganate (KMnO4) in batches. Stir for 2 hours until homogeneous. Step 1.3: Add deionized water and hydrogen peroxide (H2O2) to the solution to remove KMnO4. Add the solution to dilute hydrochloric acid and let it stand for 12 hours; take the lower layer of the mixed solution and dialyze it in water for 48 hours. Stir the solution at high speed for 5 hours. Step 1.4: After pre-cooling the GO dispersion obtained above, freeze-dry it using a freeze dryer to obtain GO powder.

[0027] The pre-cooling temperature is -31℃, and the pre-cooling time is 60 minutes. The freeze-drying temperature was -40℃, and the freeze-drying time was 72 hours. Step 2: Following Step 1, pure rGO aerogel composite material is prepared using a hydrothermal method and freeze-drying technology; specifically: Step 2.1: Add 0.03 g rGO powder to deionized water and stir for 30 min to obtain a mixed solution. Transfer the mixed solution to a high-pressure reactor and maintain it at 180 °C for 10 h. Then allow it to cool naturally to room temperature. Soak the obtained aerogel in a mixed solution of water and ethanol for 24 h to perform hydrolysis and remove excess ions; the mass ratio of water to ethanol is 10:1.

[0028] Step 2.2: After freezing the aerogel obtained above at -26°C for 12 hours, freeze-dry it at -30°C for 48 hours using a freeze dryer to obtain pure rGO aerogel.

[0029] like Figure 4 As shown, the minimum reflection loss of the pure rGO aerogel composite material prepared in Example 1 is -8.0 dB at a distance of 2.50 mm to 4.50 mm. The poor electromagnetic wave absorption performance of pure rGO aerogel is mainly due to the impedance mismatch caused by its high conductivity, which makes it difficult for incident electromagnetic waves to enter the interior of the aerogel for dissipation and attenuation, and instead they are directly reflected at the surface.

[0030] Example 2 The preparation method of FeCo-MOF / rGO aerogel composite material is as follows: Step 1: Prepare GO powder using the improved Hummer method. The specific steps are as follows: Step 1.1: Under oil bath conditions, dissolve phosphorus pentoxide (P2O5), potassium persulfate (K2S2O8), and graphite in sulfuric acid, stir for 6 hours, and mix thoroughly. The mass ratio of P2O5, K2S2O8, and graphite is 1:1:0.75.

[0031] Step 1.2: Vacuum filter the mixture and collect the precipitate. Dissolve the mixture in sulfuric acid under ice bath conditions, adding 9g of potassium permanganate (KMnO4) in batches. Stir for 2 hours until homogeneous. Step 1.3: Add deionized water and hydrogen peroxide (H2O2) to the solution to remove KMnO4. Add the solution to dilute hydrochloric acid and let it stand for 12 hours; take the lower layer of the mixed solution and dialyze it in water for 48 hours. Stir the solution at high speed for 5 hours. Step 1.4: After pre-cooling the GO dispersion obtained above, freeze-dry it using a freeze dryer to obtain GO powder.

[0032] The pre-cooling temperature is -31℃, and the pre-cooling time is 60 minutes. The freeze-drying temperature was -40℃, and the freeze-drying time was 72 hours. Step 2, FeCo-MOF powder is prepared by hydrothermal method, specifically as follows: 0.436 g Co(NO3)2·6H2O, 0.436 g Fe(NO3)3·9H2O, and 0.037 g NaBH4 powder were added to deionized water and stirred for 30 min to obtain a mixed solution. The mixed solution was transferred to a high-pressure reactor and kept at 180 °C for 12 h. Then it was allowed to cool naturally to room temperature. The precipitate was collected, centrifuged, washed, and dried to obtain FeCo-MOF powder. Step 3: Following step 2, FeCo-MOF / rGO aerogel composite material is prepared using a hydrothermal method and freeze-drying technology; specifically: Step 3.1: Add 0.03g rGO and 0.03g FeCo-MOF powder to deionized water and stir for 30 min to obtain a mixed solution. Transfer the mixed solution to a high-pressure reactor and maintain it at 180℃ for 10 h. Then allow it to cool naturally to room temperature. Soak the obtained aerogel in a mixed solution of water and ethanol for 24 h to perform hydrolysis and remove excess ions; the mass ratio of water to ethanol is 10:1.

[0033] Step 3.2: After freezing the aerogel obtained above at -26℃ for 12h, freeze-dry it at -30℃ for 48h using a freeze dryer to obtain FeCo-MOF / rGO aerogel.

[0034] like Figure 5 As shown, the FeCo-MOF / rGO aerogel composite material prepared in Example 2 exhibits a minimum reflection loss of -18.1 dB at a distance of 2.50 mm to 4.50 mm. The poor electromagnetic wave absorption performance of FeCo-MOF / rGO aerogel is mainly due to the lack of synergy between impedance matching and electromagnetic wave attenuation. Although the introduction of FeCo-MOF alone can effectively reduce the dielectric constant of rGO and improve its impedance mismatch, it cannot achieve synergistic optimization of impedance matching and electromagnetic wave attenuation.

[0035] Example 3 The preparation method of FeCoSe / rGO aerogel composite material is as follows: Step 1: Prepare GO powder using the improved Hummer method. The specific steps are as follows: Step 1.1: Under oil bath conditions, dissolve phosphorus pentoxide (P2O5), potassium persulfate (K2S2O8), and graphite in sulfuric acid. Stir for 6 hours until homogeneous. The mass ratio of P2O5, K2S2O8, and graphite is 1:1:0.75.

[0036] Step 1.2: Vacuum filter the mixture and collect the precipitate. Dissolve the mixture in sulfuric acid under ice bath conditions, adding 9g of potassium permanganate (KMnO4) in batches. Stir for 2 hours until homogeneous. Step 1.3: Add deionized water and hydrogen peroxide (H2O2) to the solution to remove KMnO4. Add the solution to dilute hydrochloric acid and let it stand for 12 hours; take the lower layer of the mixed solution and dialyze it in water for 48 hours. Stir the solution at high speed for 5 hours. Step 1.4: After pre-cooling the GO dispersion obtained above, freeze-dry it using a freeze dryer to obtain GO powder.

[0037] The pre-cooling temperature is -31℃, and the pre-cooling time is 60 minutes. The freeze-drying temperature was -40℃, and the freeze-drying time was 72 hours. Step 2, FeCoSe powder is prepared by hydrothermal method, specifically as follows: 0.436 g Co(NO3)2·6H2O, 0.436 g Fe(NO3)3·9H2O, 0.078 g selenium powder, and 0.037 g NaBH4 powder were added to deionized water and stirred for 30 min to obtain a mixed solution. The mixed solution was transferred to a high-pressure reactor and kept at 180 °C for 12 h. Then it was allowed to cool naturally to room temperature. The precipitate was collected, centrifuged, washed, and dried to obtain FeCoSe powder. Step 3: Following step 2, FeCoSe / rGO aerogel composite material is prepared using a hydrothermal method and freeze-drying technology; specifically: Step 3.1: Add 0.03g rGO and 0.03g FeCoSe powder to deionized water and stir for 30 min to obtain a mixed solution. Transfer the mixed solution to a high-pressure reactor and maintain it at 180℃ for 10 h. Then allow it to cool naturally to room temperature. Soak the obtained aerogel in a mixed solution of water and ethanol for 24 h to perform hydrolysis and remove excess ions; the mass ratio of water to ethanol is 10:1.

[0038] Step 3.2: After freezing the aerogel obtained above at -26°C for 12 hours, freeze-dry it at -30°C for 48 hours using a freeze dryer to obtain FeCoSe / rGO aerogel.

[0039] like Figure 6 As shown, the FeCoSe / rGO aerogel composite material prepared in Example 3 exhibits a minimum reflection loss of -16.4 dB at a distance of 2.50 mm to 4.50 mm. The introduction of nanoflower-like FeCoSe enriches the loss mechanism for electromagnetic waves, and the introduction of low-conductivity FeCoSe reduces the dielectric constant of rGO, improving its impedance matching. However, it is difficult to achieve synergistic optimization of impedance matching and electromagnetic wave attenuation, resulting in a deterioration in electromagnetic wave absorption performance.

[0040] Example 4 The preparation method of MoS2 / rGO aerogel composite material is as follows: Step 1: Prepare GO powder using the improved Hummer method. The specific steps are as follows: Step 1.1: Under oil bath conditions, dissolve phosphorus pentoxide (P2O5), potassium persulfate (K2S2O8), and graphite in sulfuric acid. Stir for 6 hours until homogeneous. The mass ratio of P2O5, K2S2O8, and graphite is 1:1:0.75.

[0041] Step 1.2: Vacuum filter the mixture and collect the precipitate. Dissolve the mixture in sulfuric acid under ice bath conditions, adding 9g of potassium permanganate (KMnO4) in batches. Stir for 2 hours until homogeneous. Step 1.3: Add deionized water and hydrogen peroxide (H2O2) to the solution to remove KMnO4. Add the solution to dilute hydrochloric acid and let it stand for 12 hours; take the lower layer of the mixed solution and dialyze it in water for 48 hours. Stir the solution at high speed for 5 hours. Step 1.4: After pre-cooling the GO dispersion obtained above, freeze-dry it using a freeze dryer to obtain GO powder.

[0042] The pre-cooling temperature is -31℃, and the pre-cooling time is 60 minutes. The freeze-drying temperature was -40℃, and the freeze-drying time was 72 hours. Step 2, preparing MoS2 powder via a hydrothermal method, specifically as follows: Add 0.58g Na2MoO4·2H2O and 0.42g thioacetamide powder to deionized water and stir for 30 min to obtain a mixed solution. Transfer the mixed solution to a high-pressure reactor and maintain it at 200℃ for 24 h. After cooling, collect the precipitate, centrifuge, wash, and dry to obtain MoS2 powder.

[0043] Step 3: Following step 2, a MoS2 / rGO aerogel composite material is prepared using a hydrothermal method and freeze-drying technology; specifically: Step 3.1: Add 0.03 g rGO and 0.03 g MoS2 powder to deionized water and stir for 30 min to obtain a mixed solution. Transfer the mixed solution to a high-pressure reactor and maintain it at 180 °C for 10 h. Then allow it to cool naturally to room temperature. Soak the obtained aerogel in a mixed solution of water and ethanol for 24 h to perform hydrolysis and remove excess ions; the mass ratio of water to ethanol is 10:1.

[0044] Step 3.2: After freezing the aerogel obtained above at -26℃ for 12h, freeze-dry it at -30℃ for 48h using a freeze dryer to obtain MoS2 / rGO aerogel.

[0045] like Figure 7 As shown, the MoS2 / rGO aerogel composite material prepared in Example 4 exhibits a minimum reflection loss of -10.2 dB at a distance of 2.50 mm–4.50 mm. The introduction of nanoflower-like MoS2 effectively balances impedance matching and electromagnetic wave attenuation characteristics, but the introduction of a single MoS2 cannot induce sufficient polarization loss. Therefore, the MoS2 / rGO aerogel exhibits poor electromagnetic wave absorption performance.

[0046] Example 5 The preparation method of the MoS2@FeCoSe / rGO aerogel composite material of the present invention includes the following specific steps: Step 1: Prepare GO powder using the improved Hummer method. The specific steps are as follows: Step 1.1: Under oil bath conditions, dissolve phosphorus pentoxide (P2O5), potassium persulfate (K2S2O8), and graphite in sulfuric acid. Stir for 6 hours until homogeneous. The mass ratio of P2O5, K2S2O8, and graphite is 1:1:0.75.

[0047] Step 1.2: Vacuum filter the mixture and collect the precipitate. Dissolve the mixture in sulfuric acid under ice bath conditions, adding 9g of potassium permanganate (KMnO4) in batches. Stir for 2 hours until homogeneous. Step 1.3: Add deionized water and hydrogen peroxide (H2O2) to the solution to remove KMnO4. Add the solution to dilute hydrochloric acid and let it stand for 12 hours; take the lower layer of the mixed solution and dialyze it in water for 48 hours. Stir the solution at high speed for 5 hours. Step 1.4: After pre-cooling the GO dispersion obtained above, freeze-dry it using a freeze dryer to obtain GO powder.

[0048] The pre-cooling temperature is -31℃, and the pre-cooling time is 60 minutes. The freeze-drying temperature was -40℃, and the freeze-drying time was 72 hours. Step 2, FeCoSe powder is prepared by hydrothermal method, specifically as follows: 0.436 g Co(NO3)2·6H2O, 0.436 g Fe(NO3)3·9H2O, 0.078 g selenium powder, and 0.037 g NaBH4 powder were added to deionized water and stirred for 30 min to obtain a mixed solution. The mixed solution was transferred to a high-pressure reactor and kept at 180 °C for 12 h. Then it was allowed to cool naturally to room temperature. The precipitate was collected, centrifuged, washed, and dried to obtain FeCoSe powder. Step 3: Prepare MoS2@FeCoSe powder via hydrothermal method, specifically as follows: 0.58 g FeCoSe powder, 0.58 g Na2MoO4·2H2O, and 0.42 g thioacetamide powder were added to deionized water and stirred for 30 min to obtain a mixed solution. The mixed solution was transferred to a high-pressure reactor and kept at 200 °C for 24 h. After cooling, the precipitate was collected, centrifuged, washed, and dried to obtain MoS2@FeCoSe powder.

[0049] Step 4: Following step 3, a MoS2@FeCoSe / rGO aerogel composite material is prepared using a hydrothermal method and freeze-drying technology; specifically: Step 4.1: Add 0.03 g rGO and 0.03 g MoS2@FeCoSe powder to deionized water and stir for 30 min to obtain a mixed solution. Transfer the mixed solution to a high-pressure reactor and maintain it at 180 °C for 10 h. Then allow it to cool naturally to room temperature. Soak the obtained aerogel in a mixed solution of water and ethanol for 24 h to perform hydrolysis and remove excess ions; the mass ratio of water to ethanol is 10:1.

[0050] Step 4.2: After freezing the aerogel obtained above at -26℃ for 12h, freeze-dry it at -30℃ for 48h using a freeze dryer to obtain MoS2@FeCoSe / rGO aerogel.

[0051] Figure 1 and Figure 2 The image shows the morphology of the MoS2@FeCoSe / rGO aerogel composite material from Example 5. Figure 1 and Figure 2 The successful preparation of MoS2@FeCoSe / rGO aerogel can be observed. The rich porous structure of the aerogel and the loading of MoS2@FeCoSe can also be observed. The pores in its cross section have orientation. Figure 3This is the XPS image of the MoS2@FeCoSe / rGO aerogel composite. The successful preparation of the MoS2@FeCoSe / rGO aerogel can be observed. The Fe 2p, Co 2p, and Se 3d atoms in FeCoSe, and the Mo 3d and S 1s atoms in MoS2, can be clearly observed in the XPS image of the MoS2@FeCoSe / rGO aerogel.

[0052] like Figure 8 As shown, the minimum reflection loss of the MoS2@FeCoSe / rGO aerogel composite material prepared in Example 5 is -47.4dB at a distance of 2.50mm-4.50mm.

[0053] In summary, the electromagnetic wave absorption performance shows an increasing trend with the preparation of aerogels with different components. The MoS2@FeCoSe / rGO aerogel composite material exhibits excellent electromagnetic wave absorption performance.

[0054] Example 6 The preparation method of the MoS2@FeCoSe / rGO aerogel composite material of the present invention is carried out according to the following steps: Step 1: Prepare rGO powder using the improved Hummer method; the specific steps are as follows: Step 1.1: Under oil bath conditions at 90℃, phosphorus pentoxide (P2O5), potassium persulfate (K2S2O8), and graphite are dissolved in sulfuric acid and stirred for 7 hours to mix evenly. The mixture is then vacuum filtered to collect the precipitate. Under ice bath conditions at 5℃, the precipitate is dissolved in sulfuric acid and potassium permanganate (KMnO4) is added in batches. After each addition, the mixture is stirred for 3 hours to mix evenly, thus obtaining a mixed solution. The mass ratio of P2O5, K2S2O8, and graphite is 1.5:1.5:1.35; Step 1.2: Deionized water and hydrogen peroxide (H2O2) are added to the mixture from Step 1.1 to remove KMnO4. The solution is then added to dilute hydrochloric acid and allowed to stand for 24 hours. The lower layer of the mixture is then dialyzed in water for 72 hours. After dialyzing, the solution is stirred at high speed for 5 hours at a stirring rate of 3000 r / min to obtain a GO dispersion. Step 1.3: Pre-cool the obtained GO dispersion and then freeze-dry it to obtain rGO powder; The pre-cooling temperature is -31℃, and the pre-cooling time is 60 minutes. The freeze-drying temperature was -40℃, and the freeze-drying time was 72 hours. Step 2: Prepare FeCoSe powder using a hydrothermal method; specifically: Co(NO3)2·6H2O, Fe(NO3)3·9H2O, selenium powder, and NaBH4 powder were added to deionized water and stirred for 30 min to obtain a mixed solution. The mixed solution was then transferred to a high-pressure reactor for hydrothermal reaction at 180℃ for 13 h. After natural cooling to room temperature, the precipitate was collected, centrifuged and washed at a centrifugation rate of 8000 r / min, and dried to obtain FeCoSe powder. The mass ratio of Co(NO3)2·6H2O, Fe(NO3)3·9H2O, selenium powder, NaBH4, and deionized water is 1.5:1.78:3.56:0.39:4.78. Step 3: Following step 2, MoS2@FeCoSe powder is prepared; specifically: Add the FeCoSe powder, Na2MoO4·2H2O, and thioacetamide powder from the above steps to deionized water and stir for 30 min to obtain a mixed solution. Transfer the mixed solution to a high-pressure reactor and carry out a hydrothermal reaction at a reaction temperature of 210℃ for 25 h. After the reaction is completed and cooled to room temperature, collect the precipitate, centrifuge and wash it several times, and dry it to obtain MoS2@FeCoSe powder.

[0055] The mass ratio of FeCoSe powder, Na2MoO4·2H2O, thioacetamide, and deionized water is 1.5:0.97:0.63:4.78. Step 4: Following step 3, a MoS2@FeCoSe / rGO aerogel composite material is prepared using a hydrothermal method and freeze-drying technology; specifically: Step 4.1: Add rGO powder and MoS2@FeCoSe powder to deionized water and stir to obtain a mixed solution. Transfer the mixed solution to a high-pressure reactor for hydrothermal reaction at 190℃ for 11 hours. Allow it to cool naturally to room temperature and soak the resulting aerogel in a mixed solution of water and ethanol for 48 hours to hydrolyze it and remove excess ions. The mass ratio of water to ethanol was 11:1.5; the mass ratio of rGO powder, MoS2@FeCoSe powder, and deionized water was 1.5:1.5:4.5. Step 4.2: Pre-cool the aerogel obtained in step 4.1, and then freeze-dry it to obtain MoS2@FeCoSe / rGO aerogel.

[0056] The pre-cooling temperature was -31℃ and the pre-cooling time was 60 min; the freeze-drying temperature was -40℃ and the freeze-drying time was 72 h.

[0057] In this invention, a MoS2@FeCoSe / rGO aerogel composite material is prepared. The unique design of this composite material's three-dimensional porous structure and the effect of its magnetic components improve impedance matching, allowing electromagnetic waves to enter more easily. Multiple reflections and scattering occur within the porous structure, and the incident wave is attenuated through the magnetic loss of MoS2@FeCoSe and the interfacial polarization and dipole polarization induced by numerous effective interfaces, thus achieving excellent electromagnetic wave absorption. Doping with Se and S can tune the electronic structure and increase anisotropy. When the prepared MoS2@FeCoSe / rGO aerogel contains 70 wt%, the minimum reflection loss is -47.4 dB. This provides a feasible solution for fabricating materials with excellent electromagnetic wave absorption performance.

Claims

1. A method for preparing MoS2@FeCoSe / rGO aerogel composite material, characterized in that, The specific steps are as follows: Step 1: Prepare rGO powder using the modified Hummer method; Step 2: Prepare FeCoSe powder by hydrothermal method; Step 3: Add FeCoSe powder, Na2MoO4·2H2O and thioacetamide powder to deionized water, stir to obtain a mixed solution, transfer the mixed solution to a high-pressure reactor for hydrothermal reaction, centrifuge, wash and dry to obtain MoS2@FeCoSe powder; Step 4: Following step 3, the MoS2@FeCoSe / rGO aerogel composite material is prepared using a hydrothermal method and freeze-drying technology.

2. The preparation method of the MoS2@FeCoSe / rGO aerogel composite material as described in claim 1, characterized in that, In step 1, the specific steps are as follows: Step 1.1: Under oil bath conditions of 70-90℃, P2O5, K2S2O8 and graphite are dissolved in sulfuric acid and stirred for 5-7 hours until they are mixed evenly. The mixture is then vacuum filtered to collect the precipitate. Under ice bath conditions of 3-5℃, the precipitate is dissolved in sulfuric acid and potassium permanganate is added in batches. After each addition, the mixture is stirred for 1-3 hours until it is mixed evenly to obtain a mixed solution. Step 1.2: Add deionized water and H2O2 to the mixture from Step 1.1, then add dilute hydrochloric acid and let stand for 12-24 hours; take the lower layer of the mixture and dialyze it in water. After dialyzing, stir for 3-5 hours at a stirring rate of 2000-3000 r / min to obtain a GO dispersion. Step 1.3: Pre-cool the obtained GO dispersion and then freeze-dry it to obtain rGO powder.

3. The preparation method of the MoS2@FeCoSe / rGO aerogel composite material as described in claim 2, characterized in that, In step 1.1, the mass ratio of P2O5, K2S2O8, and graphite is 0.5-1.5:0.5-1.5:0.25-1.

35. In step 1.3, the pre-cooling temperature is -21 to -31°C and the pre-cooling time is 30 to 60 minutes; the freeze-drying temperature is -30 to -40°C and the freeze-drying time is 48 to 72 hours.

4. The method for preparing the MoS2@FeCoSe / rGO aerogel composite material as described in claim 1, characterized in that, Step 2 specifically involves: Co(NO3)2·6H2O, Fe(NO3)3·9H2O, selenium powder, and NaBH4 powder were added to deionized water and stirred for 20-30 minutes to obtain a mixed solution. The mixed solution was then transferred to a high-pressure reactor for hydrothermal reaction. After cooling, the precipitate was collected, centrifuged, washed, and dried to obtain FeCoSe powder.

5. The method for preparing the MoS2@FeCoSe / rGO aerogel composite material as described in claim 4, characterized in that, The hydrothermal reaction temperature is 170-180℃, and the hydrothermal reaction time is 11-13h; the mass ratio of Co(NO3)2·6H2O, Fe(NO3)3·9H2O, selenium powder, NaBH4, and deionized water is 0.5-1.5:0.36-1.78:0.58-3.56:0.13-0.39:3.42-4.

78.

6. The method for preparing the MoS2@FeCoSe / rGO aerogel composite material as described in claim 1, characterized in that, In step 3, the mass ratio of FeCoSe powder, Na2MoO4·2H2O, thioacetamide, and deionized water is 0.5-1.5:0.29-0.97:0.12-0.63:3.42-4.78; the reaction temperature is 190-210℃; the reaction time is 23-25h; and the stirring time is 20-30min.

7. The method for preparing the MoS2@FeCoSe / rGO aerogel composite material as described in claim 1, characterized in that, Step 4 specifically involves: Step 4.1: Add rGO powder and MoS2@FeCoSe powder to deionized water, stir to obtain a mixed solution, transfer the mixed solution to a high-pressure reactor for hydrothermal reaction, cool naturally to room temperature, and soak the obtained aerogel in a mixed solution of water and ethanol for 24-48 hours for hydrolysis. Step 4.2: Pre-cool the aerogel obtained in step 4.1, and then freeze-dry it to obtain MoS2@FeCoSe / rGO aerogel.

8. The method for preparing the MoS2@FeCoSe / rGO aerogel composite material as described in claim 7, characterized in that, In step 4.1, the reaction temperature is 170-190℃ and the reaction time is 9-11h; the mass ratio of rGO powder, MoS2@FeCoSe powder and deionized water is 0.5-1.5:0.5-1.5:1.5-4.

5.

9. The method for preparing the MoS2@FeCoSe / rGO aerogel composite material as described in claim 7, characterized in that, In step 4.2, the pre-cooling temperature is -21 to -31°C and the pre-cooling time is 30 to 60 minutes; the freeze-drying temperature is -30 to -40°C and the freeze-drying time is 48 to 72 hours.

10. The composite material prepared by the method for preparing MoS2@FeCoSe / rGO aerogel composite material according to any one of claims 1-9.

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