Preparation method and application of a bimetallic oxide / carbon composite material

Abstract

The application provides a preparation method of a double-metal oxide / carbon composite material, which comprises the following steps: uniformly mixing N,N-dimethylformamide liquid, methanol and deionized water to obtain solution A; uniformly mixing a carbon source, a chloride salt, ferrous chloride tetrahydrate, 2,5-dihydroxyterephthalic acid and deionized water to obtain solution B; uniformly mixing solution A and solution B, and then performing a heating reaction; centrifuging the obtained product, washing and drying the product to obtain the double-metal oxide / carbon composite material. The magnetic loss type material and the loss type material are applied in the electromagnetic wave absorption field in a composite mode, the advantages of the two are fully exerted, the synergistic effect of the composite material is exhibited, the wave absorbing material has a lower reflection loss value, a higher absorption frequency and a wider effective bandwidth. The double-metal oxide / carbon composite material will become a very promising wave absorbing material due to its excellent properties.

Description

Technical Field

[0001] This invention belongs to the field of electromagnetic wave absorbing materials technology, specifically relating to a method for preparing a bimetallic oxide / carbon composite material and its application. Background Technology

[0002] With the rapid development of modern science and technology, communication technology, stealth technology, and electromagnetic compatibility technology have been widely applied. Electromagnetic pollution has become a new type of pollution following traditional pollution such as air pollution and light pollution. Under this new development, how to reduce electromagnetic interference and the impact of electromagnetic radiation on people's production and life has become a widely concerned issue. High-performance absorbing materials have the advantages of thinness, light weight, strong absorption performance, and wide absorption bandwidth, thus having high application value. According to their different absorption mechanisms, absorbing materials are mainly divided into two categories: dielectric loss materials and magnetic loss materials. Generally speaking, dielectric loss materials are mainly carbonaceous materials, silicon carbide, barium titanate, etc. Magnetic loss materials include some iron, cobalt, and nickel-based magnetic materials. In current research on absorbing materials, since it is difficult for a single-component absorber to simultaneously meet the problems of loss characteristics and impedance matching, combining electrical loss type materials with magnetic loss type materials to give full play to the advantages of both and prepare composite absorbing materials has become a major research hotspot.

[0003] Cobalt ferrite (CoFe2O4) exhibits high resistivity and hysteresis loss due to its excellent chemical stability and strong magnetic loss capability. CoFe2O4 makes it an ideal choice for microwave and wireless electronic applications. Therefore, composite materials based on carbon materials and CoFe2O4 have received widespread attention in recent years. An important and effective strategy is to optimize the microstructure of the materials to effectively improve absorption performance. Notably, metal-organic frameworks (MOFs), as a novel type of porous crystalline material, have attracted widespread attention in various fields due to their high surface area, periodic network structure, and tunable pore size. As expected, MOF-derived composite materials inherit the unique nanoframework and porous structure of MOFs, exhibiting excellent electromagnetic wave absorption capabilities in the GHz frequency range. Therefore, the synthesis of MOF-derived composite absorbing materials warrants further investigation. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address the shortcomings of the prior art by providing a method for preparing a bimetallic oxide / carbon composite material and its application. The preparation method uses a bimetallic organic framework to derive the bimetallic oxide / carbon composite material, thereby improving the absorption performance and broadening the absorption band of the composite material.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for preparing a bimetallic oxide / carbon composite material, the preparation method comprising the following steps:

[0006] S1. Mix N,N-dimethylformamide liquid, methanol and deionized water evenly to obtain solution A;

[0007] S2. Mix the carbon source, chloride salt, ferrous chloride tetrahydrate, 2,5-dihydroxyterephthalic acid and deionized water evenly to obtain solution B;

[0008] S3. Mix solution A obtained in S1 and solution B obtained in S2, stir evenly, and then heat to react to obtain the product; after centrifuging the product, wash it with methanol and then dry it to obtain bimetallic organic framework / carbon powder.

[0009] S4. The bimetallic organic framework / carbon powder obtained in S3 is calcined at high temperature to obtain a bimetallic oxide / carbon composite material.

[0010] Preferably, the volume ratio of N,N-dimethylformamide liquid, methanol and deionized water in S1 is 10:(1-5):(0.5-2).

[0011] Preferably, the carbon source in S2 is glucose, citric acid, or graphene; the chloride salt is cobalt chloride hexahydrate or nickel chloride hexahydrate; and the ratio of the amount of carbon source, chloride salt, ferrous chloride tetrahydrate, 2,5-dihydroxyterephthalic acid, and deionized water is (1-10)g:(3-9)g:(4-12)g:(2-8)g:1L.

[0012] Preferably, in S3, the volume ratio of solution A to solution B is 6:1; the stirring time is 20-40 min, and the stirring speed is 400-600 rpm; the heating reaction temperature is 115-185℃, and the heating time is 20-32 h.

[0013] Preferably, the centrifugation speed in step S3 is 3000-5000 r / min; the methanol washing is performed 3-6 times; and the drying temperature is 60-80℃ for 8-12 h.

[0014] Preferably, the heating rate of the high-temperature calcination in S4 is 5℃ / min, the temperature is 500-800℃, and the time is 1-3h.

[0015] The present invention also provides an application of the bimetallic oxide / carbon composite material prepared by the above preparation method, wherein the bimetallic oxide / carbon composite material is used as an electromagnetic wave absorbing material.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] The preparation method of bimetallic oxides / carbons by deriving bimetallic organic frameworks can be extended to the preparation of most bimetallic oxides / carbons, providing a good option for the preparation and development of bimetallic oxide materials.

[0018] The introduction of carbon significantly increases the dielectric loss of the material in the high-frequency range, thereby improving magnetic energy dissipation across the entire frequency range. Furthermore, the bimetallic organic framework-derived composite material inherits its unique nanoframework and porous structure, exhibiting excellent electromagnetic wave absorption capabilities in the GHz frequency range. In particular, its effective absorption bandwidth indicates its enormous application potential in electromagnetic field absorption fields.

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

[0020] Figure 1 The image shows the SEM morphology of the bimetallic organic framework / carbon (NiFe-MOF / C) powder prepared in Example 1.

[0021] Figure 2 The image shows the SEM morphology of the bimetallic oxide / carbon (NiFe2O4 / C) composite material prepared in Example 1.

[0022] Figure 3 The image shows the SEM morphology of the bimetallic oxide / carbon (CoFe-MOF / C) powder prepared in Example 2.

[0023] Figure 4 The image shows the SEM morphology of the bimetallic oxide / carbon (CoFe2O4 / C) composite material prepared in Example 2.

[0024] Figure 5 The image shows the SEM morphology of the bimetallic oxide / carbon (CoFe2O4 / graphene) composite material in Example 4.

[0025] Figure 6 The reflection loss diagram is shown for the bimetallic oxide / carbon (NiFe2O4 / C) composite material prepared in Example 1.

[0026] Figure 7 The reflection loss diagram is shown for the bimetallic oxide / carbon (CoFe2O4 / C) composite material prepared in Example 2.

[0027] Figure 8 The reflection loss diagram is shown for the bimetallic oxide / carbon (CoFe2O4 / C) composite material prepared in Example 3.

[0028] Figure 9The image shows the reflection loss of the bimetallic oxide / carbon (CoFe2O4 / graphene) composite material prepared in Example 4. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Example 1

[0031] The preparation method of the bimetallic oxide / carbon composite material in this embodiment includes the following steps:

[0032] S1. Mix N,N-dimethylformamide liquid, methanol and deionized water in a volume ratio of 10:1:1.5 and stir magnetically for 15 minutes at a speed of 500 rpm to obtain solution A.

[0033] S2. Dissolve 0.01g glucose, 0.03g nickel chloride hexahydrate, 0.04g ferrous chloride tetrahydrate and 0.04g 2,5-dihydroxyterephthalic acid in 10mL of deionized water and stir at 500rpm for 30min to obtain solution B.

[0034] S3. Mix solution A obtained in S1 and solution B obtained in S2 at a volume ratio of 6:1, stir at a speed of 500 rpm for 30 min, then transfer to a reaction vessel, heat at a temperature of 120℃ for 20 h, after cooling, centrifuge the obtained product at a speed of 4000 r / min, wash with methanol 3 times, and dry in a vacuum drying oven at a temperature of 70℃ for 10 h to obtain bimetallic organic framework / carbon powder, i.e. NiFe-MOF / C powder;

[0035] S4. The bimetallic organic framework / carbon powder obtained in S3 is placed in a tube furnace and heated to 600°C at a heating rate of 5°C / min. It is then calcined at 600°C for 2 hours to obtain the bimetallic oxide / carbon (NiFe2O4 / C) composite material.

[0036] Example 2

[0037] The preparation method of the bimetallic oxide / carbon composite material in this embodiment includes the following steps:

[0038] S1. Mix N,N-dimethylformamide liquid, methanol and deionized water in a volume ratio of 10:1:1 and stir magnetically for 15 minutes at a speed of 500 rpm to obtain solution A.

[0039] S2. Dissolve 0.05g glucose, 0.05g cobalt chloride hexahydrate, 0.07g ferrous chloride tetrahydrate and 0.07g 2,5-dihydroxyterephthalic acid in 10mL of deionized water and stir at 500rpm for 30min to obtain solution B.

[0040] S3. Mix solution A obtained in S1 and solution B obtained in S2 at a volume ratio of 6:1, stir at a speed of 550 rpm for 28 min, then transfer to a reaction vessel and heat at a temperature of 140℃ for 24 h. After cooling, centrifuge the obtained product at a speed of 4500 r / min, wash it 4 times with methanol, and dry it in a vacuum drying oven at a temperature of 75℃ for 11 h to obtain bimetallic organic framework / carbon powder, namely CoFe-MOF / C powder.

[0041] S4. The bimetallic organic framework / carbon powder obtained in S3 is placed in a tube furnace and heated to 700℃ at a heating rate of 5℃ / min. It is then calcined at 700℃ for 1 hour to obtain the bimetallic oxide / carbon (CoFe2O4 / C) composite material.

[0042] Example 3

[0043] The preparation method of the bimetallic oxide / carbon composite material in this embodiment includes the following steps:

[0044] S1. Mix N,N-dimethylformamide liquid, methanol and deionized water in a volume ratio of 10:2:1 and stir magnetically for 15 minutes at a speed of 500 rpm to obtain solution A.

[0045] S2. Dissolve 0.1g citric acid, 0.06g cobalt chloride hexahydrate, 0.09g ferrous chloride tetrahydrate and 0.07g 2,5-dihydroxyterephthalic acid in 10mL of deionized water and stir at 500rpm for 30min to obtain solution B.

[0046] S3. Mix solution A obtained in S1 and solution B obtained in S2 at a volume ratio of 6:1, stir at a speed of 400 rpm for 40 min, then transfer to a reaction vessel and heat at a temperature of 160℃ for 20 h. After cooling, centrifuge the obtained product at a speed of 3000 r / min, wash it 5 times with methanol, and dry it in a vacuum drying oven at a temperature of 60℃ for 12 h to obtain bimetallic organic framework / carbon powder, namely CoFe-MOF / C powder.

[0047] S4. The bimetallic organic framework / carbon powder obtained in S3 is placed in a tube furnace and heated to 800℃ at a heating rate of 5℃ / min. It is then calcined at 800℃ for 1 hour to obtain the bimetallic oxide / carbon (CoFe2O4 / C) composite material.

[0048] Example 4

[0049] The preparation method of the bimetallic oxide / carbon composite material in this embodiment includes the following steps:

[0050] S1. Mix N,N-dimethylformamide liquid, methanol and deionized water in a volume ratio of 10:2:2 and stir magnetically for 15 minutes at a speed of 500 rpm to obtain solution A.

[0051] S2. Dissolve 0.01g graphene, 0.06g cobalt chloride hexahydrate, 0.1g ferrous chloride tetrahydrate and 0.08g 2,5-dihydroxyterephthalic acid in 10mL of deionized water and stir at 500rpm for 30min to obtain solution B.

[0052] S3. Mix solution A obtained in S1 and solution B obtained in S2 at a volume ratio of 6:1, stir at a speed of 600 rpm for 20 min, then transfer to a reaction vessel and heat at a temperature of 140℃ for 30 h. After cooling, centrifuge the obtained product at a speed of 5000 r / min, wash with methanol 6 times, and dry in a vacuum drying oven at a temperature of 80℃ for 8 h to obtain bimetallic organic framework / carbon powder, i.e., CoFe-MOF / C powder.

[0053] S4. The bimetallic organic framework / carbon powder obtained in S3 is placed in a tube furnace and heated to 800℃ at a heating rate of 5℃ / min. It is then calcined at 800℃ for 2 hours to obtain a bimetallic oxide / carbon (CoFe2O4 / graphene) composite material.

[0054] In this embodiment, the volume ratio of N,N-dimethylformamide liquid, methanol, and deionized water in S1 can also be 10:5:0.5; the ratio of carbon source, chloride salt, ferrous chloride tetrahydrate, 2,5-dihydroxyterephthalic acid, and deionized water in S2 can also be 5g:9g:12g:2g:1L; the heating reaction temperature in S3 can also be 115℃, 125℃, 130℃, 135℃, 145℃, 150℃, 155℃, 170℃, 180℃, 182℃, or 185℃, and the reaction time can also be... The time can be 21h, 22h, 23h, 24h, 25h, 27h, 28h, 29h, 30h, 30.5h, 31h or 32h; the high-temperature calcination temperature mentioned in S4 can also be 500℃, 550℃, 570℃, 620℃, 650℃, 680℃, 710℃, 750℃, 750℃, 770℃ or 790℃, and the time can also be 1.2h, 1.5h, 1.8h, 2h, 2.3h, 2.4h, 2.5h, 2.6h, 2.8h, 2.9h or 3h.

[0055] The bimetallic oxide / carbon composite materials prepared in Examples 1-4 were tested respectively, and the specific test procedures are as follows:

[0056] 0.75g of the bimetallic oxide / carbon composite material prepared in Examples 1-4 was weighed as a sample and mixed with 0.75g of paraffin wax in a beaker. A 3mm thickness was used as the standard for pressing the mixture into a ring. The resulting pressed pellet was then placed in a sample bag for characterization and testing. A vector network analyzer (model N 5230C, manufactured by a US company) was used to process the reflection loss corresponding to different coating thicknesses at different frequencies (2-18GHz), and the absorption performance of the samples was simulated.

[0057] See attached for detailed test results. Figure 5-8 .

[0058] Through append Figure 1 It can be seen that the NiFe-MOF / C powder prepared in Example 1 has a clustered structure of small spheres. (The last sentence appears to be incomplete and possibly contains errors.) Figure 2 It can be seen that the NiFe2O4 / C composite material prepared in Example 1 has a cluster structure of small spheres.

[0059] Through append Figure 3 It can be seen that the CoFe-MOF / C powder prepared in Example 2 has a somewhat irregular polyhedral structure. (The remaining text appears to be incomplete and requires further context.) Figure 4 It can be seen that the CoFe2O4 / C composite material prepared in Example 2 has a regular polyhedral structure, inheriting the unique nanoframework and porous structure of the bimetallic organic framework, which is beneficial to improving the microwave absorption performance.

[0060] Through append Figure 5 It can be seen that the CoFe2O4 / graphene prepared in Example 4 is a polyhedral structure coated with graphene. The interaction between the two is beneficial to improving the microwave absorption performance.

[0061] Through append Figure 6 It can be seen that the NiFe2O4 / C composite microwave absorbing material prepared in Example 1 has an absorption intensity of -28.4dB at 17.0GHz, with an optimal matching thickness of 2.5mm.

[0062] Through append Figure 7 It can be seen that the CoFe2O4 / C composite microwave absorbing material prepared in Example 2 has an absorption intensity of -28.7dB at 15.2GHz and an optimal matching thickness of 2.0mm.

[0063] Through append Figure 8 As can be seen, the CoFe2O4 / C composite material prepared in Example 3 exhibits excellent electromagnetic absorption performance. Below -10dB, it achieves an effective absorption of 90% of electromagnetic waves, corresponding to the effective absorption band. This indicates effective absorption capability within the 9.0-16.3GHz range, with an effective absorption frequency band of 7.3GHz. Furthermore, when the sample coating thickness is 2.0mm, the material exhibits the best absorption performance at 13.8GHz, reaching -27.4dB. The CoFe2O4 / C composite material is a lightweight and highly efficient novel electromagnetic absorbing material that can be widely applied in various aspects of the field of electromagnetic wave absorbing materials, thereby effectively reducing the impact of electromagnetic waves on production and daily life.

[0064] Through append Figure 9 It can be seen that when the thickness is 2.0 mm and the frequency is 12.2 GHz, the optimal reflection loss of the CoFe2O4 / graphene composite material prepared in Example 4 can reach -24.0 dB.

[0065] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing a bimetallic oxide / carbon composite material, characterized in that, The preparation method includes the following steps: S1. Mix N,N-dimethylformamide liquid, methanol and deionized water evenly to obtain solution A; The volume ratio of the N,N-dimethylformamide liquid, methanol, and deionized water is 10:(1-5):(0.5-2). S2. Mix the carbon source, chloride salt, ferrous chloride tetrahydrate, 2,5-dihydroxyterephthalic acid and deionized water evenly to obtain solution B; The carbon source is glucose, citric acid, or graphene; the chloride salt is cobalt chloride hexahydrate or nickel chloride hexahydrate; the ratio of the carbon source, chloride salt, ferrous chloride tetrahydrate, 2,5-dihydroxyterephthalic acid, and deionized water is (1-10) g: (3-9) g: (4-12) g: (2-8) g: 1 L; S3. Mix solution A obtained in S1 and solution B obtained in S2, stir evenly, and then heat to react to obtain the product; after centrifuging the product, wash it with methanol and then dry it to obtain bimetallic organic framework / carbon powder. The volume ratio of solution A to solution B is 6:1; the stirring time is 20-40 min, and the stirring speed is 400-600 rpm; the heating reaction temperature is 115-185℃, and the heating time is 20-32 h. The centrifugation speed is 3000-5000 r / min; the washing with methanol is performed 3-6 times; the drying temperature is 60-80℃ and the time is 8-12 h. S4. The bimetallic organic framework / carbon powder obtained in S3 is calcined at high temperature to obtain a bimetallic oxide / carbon composite material. The heating rate of the high-temperature calcination is 5℃ / min, the temperature is 500-800℃, and the time is 1-3h.

2. An application of the bimetallic oxide / carbon composite material prepared by the preparation method as described in claim 1, characterized in that, The bimetallic oxide / carbon composite material is used as an electromagnetic wave absorbing material.

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