Hollow ferroferric oxide nanoparticles as well as preparation method and application thereof
By preparing hollow iron tetraoxide nanoparticles and mixing them with polypyrrole to form microwave absorbing materials, the shortcomings of existing materials in microwave absorption performance, stability and density are solved, and excellent microwave absorption performance and stability are achieved, which is suitable for industrial production and applications.
Patent Information
- Application Number
- CN202510153182.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-12
- Publication Date
- 2025-06-10
AI Technical Summary
The existing microwave absorbing materials have shortcomings in microwave absorption performance, chemical stability and density, and are difficult to meet the needs of practical applications.
Hollow iron tetraoxide nanoparticles, which have an open hollow spherical structure and microporous structure, are prepared by solvothermal reaction and calcination steps, and are mixed with polypyrrole to form a microwave absorbing material.
It achieves excellent microwave absorption performance, improves the chemical stability and lightweight properties of the material, and has a simple preparation method and low production cost, making it suitable for large-scale industrial production and application.
Smart Images
Figure CN120117660A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of electromagnetic protection materials, and particularly relates to a hollow iron oxide (Fe₃O₄) nanoparticle, a preparation method thereof, and an application thereof. Background Art
[0002] With the rapid development of the electronics and communication industries, the problem of electromagnetic wave radiation has attracted increasing attention. Electromagnetic wave radiation not only affects the precise operation of high-precision equipment, but also poses potential hazards to human health. Microwave absorption materials can absorb electromagnetic waves and are an effective means to solve electromagnetic wave radiation. However, existing microwave absorption materials generally have problems such as poor microwave absorption performance, poor chemical stability, and high density, making it difficult to fully meet the requirements of practical applications.
[0003] Therefore, it is of great significance to develop a microwave absorption material with excellent microwave absorption performance, good stability, and light weight. Summary of the Invention
[0004] The purpose of the present invention is to provide a hollow iron oxide (Fe₃O₄) nanoparticle, a preparation method thereof, and an application thereof.
[0005] The technical solution adopted by the present invention is as follows:
[0006] A hollow iron oxide (Fe₃O₄) nanoparticle has an open hollow spherical structure, with a particle size of 400 nm to 1000 nm and the diameter of the internal cavity being 200 nm to 500 nm; the hollow iron oxide (Fe₃O₄) nanoparticle contains micropores with a diameter of 10 nm to 60 nm.
[0007] A preparation method of a hollow iron oxide (Fe₃O₄) nanoparticle as described above includes the following steps:
[0008] 1) Dispersing an iron salt, sodium acetate, polyethylene glycol, and polystyrene microspheres in ethylene glycol for a solvothermal reaction to obtain magnetic nanoparticles;
[0009] 2) Washing the magnetic nanoparticles with tetrahydrofuran multiple times or calcining them in a protective atmosphere to obtain the hollow iron oxide (Fe₃O₄) nanoparticles.
[0010] Preferably, a preparation method of a hollow iron oxide (Fe₃O₄) nanoparticle as described above includes the following steps:
[0011] 1) Dispersing an iron salt, sodium acetate, polyethylene glycol, and polystyrene microspheres in ethylene glycol for a solvothermal reaction, then performing cyclic washing of the product with ethanol and water, and then performing magnetic separation of the product with a magnet to obtain magnetic nanoparticles;
[0012] 2) Wash the magnetic nanoparticles with tetrahydrofuran multiple times, then cyclically wash the product with ethanol and water, and then magnetically separate the product with a magnet. Alternatively, calcine the magnetic nanoparticles in a protective atmosphere to obtain hollow iron oxide nanoparticles.
[0013] Preferably, the mass ratio of the iron salt, sodium acetate, polyethylene glycol, and polystyrene microspheres in step 1) is 1:1-2:0.2-0.7:0.02-0.04.
[0014] Preferably, the iron salt in step 1) is at least one of ferric chloride, ferric sulfate, and ferric nitrate.
[0015] Preferably, the number average molecular weight of the polyethylene glycol in step 1) is 1800 g / mol-2200 g / mol.
[0016] Preferably, the particle size of the polystyrene microspheres in step 1) is 200 nm-500 nm.
[0017] Preferably, the solvothermal reaction in step 1) is carried out at a temperature of 150 °C-250 °C for a reaction time of 10 h-14 h.
[0018] Preferably, the calcination in step 2) is carried out at a temperature of 350 °C-450 °C for a calcination time of 2 h-5 h.
[0019] A microwave absorption material, the composition of which includes polypyrrole and the above-mentioned hollow iron oxide nanoparticles.
[0020] Preferably, the mass ratio of the polypyrrole and the hollow iron oxide nanoparticles is 1:1-2.
[0021] Preferably, the number average molecular weight of the polypyrrole is 1500 g / mol-2000 g / mol.
[0022] A preparation method of the microwave absorption material as described above includes the following steps: Mix the polypyrrole and the hollow iron oxide nanoparticles to obtain the microwave absorption material.
[0023] The beneficial effects of the present invention are as follows: The hollow iron oxide nanoparticles of the present invention can achieve the coupling effect of interfacial polarization and resistance loss to enhance dielectric loss, have excellent microwave absorption performance, and have good stability, light weight, simple preparation method, and low production cost. The microwave absorption material prepared by dispersing it in polypyrrole has excellent electromagnetic shielding effect and is suitable for large-scale industrial production and application. Description of the Drawings
[0024] Figure 1 It is the SEM diagram of the hollow iron oxide nanoparticles in the examples.
[0025] Figure 2 It is the particle size distribution diagram of the hollow iron oxide nanoparticles in the examples.
[0026] Figure 3 It is the XRD diagram of the hollow iron oxide nanoparticles in the examples.
[0027] Figure 4 It is the nitrogen adsorption-desorption isotherm curve of the hollow iron oxide nanoparticles in the examples.
[0028] Figure 5 It is the hysteresis loop of the hollow iron oxide nanoparticles in the examples.
[0029] Figure 6 It is the XPS diagram of the microwave absorbing material in the examples.
[0030] Figure 7 It is the infrared spectrum diagram of the microwave absorbing material in the examples.
[0031] Figure 8 It is the 3D reflection loss diagram and 2D mapping diagram of the microwave absorbing material in the examples.
[0032] Figure 9 It is the reflection loss and electromagnetic shielding diagram of the microwave absorbing material in the examples.
[0033] Figure 10 It is the test result diagram of the real part, imaginary part and dielectric loss factor of the relative complex permittivity of the microwave absorbing material in the examples.
[0034] Figure 11 It is the test result diagram of the relative complex permeability of the microwave absorbing material in the examples.
[0035] Figure 12 It is the reflection loss diagram of the microwave absorbing material with different mass ratios of polypyrrole and hollow iron oxide nanoparticles. Detailed implementation mode
[0036] The present invention will be further explained and illustrated below in conjunction with specific examples.
[0037] Example:
[0038] A kind of hollow iron oxide nanoparticles, and its preparation method is as follows:
[0039] 1) 1.89 g of ferric chloride hexahydrate, 2.52 g of sodium acetate, 0.875 g of PEG-2000, and 2 mL of a polystyrene microsphere dispersion with a concentration of 25 g / L (particle size 200 nm to 500 nm) were added to 35 mL of ethylene glycol, stirred overnight, then transferred to a high-pressure reactor and reacted at 200 °C for 12 h. The product was then washed cyclically with ethanol and water, and magnetically separated using a magnet to obtain magnetic nanoparticles;
[0040] 2) The magnetic nanoparticles were washed multiple times with tetrahydrofuran, then washed cyclically with ethanol and water, and magnetically separated using a magnet to obtain hollow iron oxide nanoparticles (denoted as H-Fe 3 O 4 ).
[0041] A microwave absorption material, the preparation method thereof is as follows:
[0042] Polypyrrole (number average molecular weight 1700 g / mol; PPY) and the above-mentioned hollow iron oxide nanoparticles were stirred and mixed evenly according to a mass ratio of 1:1 to obtain a microwave absorption material (denoted as H-Fe 3 O 4 +PPY).
[0043] Performance test:
[0044] 1) The scanning electron microscope (SEM) images of the hollow iron oxide nanoparticles in this example are as shown in Figure 1 (a and b are SEM images at different magnifications), and the particle size distribution diagram is as shown in Figure 2 .
[0045] From Figure 1 and Figure 2 it can be seen that: the hollow iron oxide nanoparticles have an open hollow spherical structure, the particle size is concentrated in the range of 400 nm to 1000 nm, and the diameter of the internal cavity is concentrated in the range of 200 nm to 500 nm.
[0046] 2) The X-ray diffraction (XRD) pattern of the hollow iron oxide nanoparticles in this example is as shown in Figure 3 .
[0047] From Figure 3 it can be seen that: the phase composition of the hollow iron oxide nanoparticles is iron oxide.
[0048] 3) The nitrogen adsorption-desorption isotherm curve of the hollow iron oxide nanoparticles in this example is as shown in Figure 4 .
[0049] From Figure 4It can be known that the hollow iron oxide nanoparticles contain micropores with a diameter of 15 nm to 55 nm.
[0050] 4) The magnetic properties of the hollow iron oxide nanoparticles in this example were tested using a vibrating sample magnetometer, and the obtained hysteresis loop is as Figure 5 shown.
[0051] From Figure 5 it can be known that the hollow iron oxide nanoparticles have the characteristics of a weak soft magnetic material.
[0052] 5) The X-ray photoelectron spectroscopy (XPS) diagram of the microwave absorption material in this example is as Figure 6 shown.
[0053] From Figure 6 it can be known that the composition elements of the microwave absorption material are elements such as carbon, nitrogen, oxygen, and iron.
[0054] 6) The infrared spectrum diagram of the microwave absorption material in this example is as Figure 7 shown.
[0055] From Figure 7 it can be known that the microwave absorption material contains the high molecular polymer polypyrrole.
[0056] 7) The complex dielectric parameters and complex magnetic permeability of the microwave absorption material in this example were tested using an Agilent N5242A PNA-X vector network analyzer. The testing process: The microwave absorption material and paraffin were ground and mixed evenly according to a mass ratio of 1:0.25 (the mass percentages of PPY, H-Fe 3 O 4 and paraffin are 40%, 40%, and 20% in sequence), then injected into a mold and pressed into a circular ring sample (outer diameter is 6.99 mm, inner diameter is 2.99 mm), and then the electromagnetic parameters in the frequency range of 2 GHz to 18 GHz were tested by the coaxial probe method. The obtained 3D reflection loss diagram and 2D mapping diagram are as Figure 8 (a is the 3D reflection loss diagram, b is the 2D mapping diagram) shown, and the reflection loss and electromagnetic shielding diagram are as Figure 9 (a is the reflection loss diagram, b is the electromagnetic shielding diagram) shown. The real part (ε r ′), imaginary part (ε r ″), and dielectric loss factor (tanδ e ) test results are as Figure 10 (a is ε r ′, b is ε r ″, c is tanδ e ) shown, and the relative complex magnetic permeability (μ r = μ r ′ - jμ r ″) test results are asFigure 11 as shown
[0057] It can be seen from Figure 8 that the distribution of the minimum reflection loss of the microwave absorption material under different thicknesses (1 mm to 5 mm) in the frequency range of 2 GHz to 18 GHz is obtained.
[0058] It can be seen from Figure 9 a in that when the thickness is 2 mm, the minimum reflection loss of the microwave absorption material is -41.041 dB ± 5 dB, and the effective absorption bandwidth (EBW(RL ≤ -10 dB)) is 3.44 GHz ± 0.5 GHz, and the effective absorption band covers the X band.
[0059] It can be seen from Figure 9 b in that the microwave absorption material does not have significant microwave shielding performance, only electromagnetic wave absorption performance.
[0060] It can be seen from Figure 10 that the dielectric loss is the main reason for the microwave absorption material to achieve electromagnetic wave absorption.
[0061] It can be seen from Figure 11 that the relative complex permeability obtained by the coaxial probe method test is a stable and reliable test result.
[0062] 8) The complex permittivity and complex permeability of hollow Fe₃O₄ nanoparticles with different ratios are measured by using an Agilent N5242A PNA-X vector network analyzer in the United States. The test process: The hollow Fe₃O₄ nanoparticles and paraffin are ground and mixed evenly according to the mass ratio of 1:0.2 to 0.8, and then injected into a mold and pressed into a circular ring sample (outer diameter is 6.99 mm, inner diameter is 2.99 mm). Then, the electromagnetic parameters in the frequency range of 2 GHz to 18 GHz are measured by the coaxial probe method, and the obtained reflection loss diagram is as Figure 12 shown
[0063] It can be seen from Figure 12 that
[0064] a) As the ratio of hollow Fe₃O₄ nanoparticles increases, the hollow Fe₃O₄ nanoparticles show certain microwave absorption performance. However, when only using hollow Fe₃O₄ nanoparticles (without using polypyrrole), the ratio of hollow Fe₃O₄ nanoparticles is greater than 80% to have significant microwave absorption performance. At this time, the ratio of hollow Fe₃O₄ nanoparticles is too large, and the pressed circular ring sample is loose in texture and easy to break, and does not have practical application value;
[0065] b) Composite the hollow Fe₃O₄ nanoparticles and polypyrrole. When the proportion of the hollow Fe₃O₄ nanoparticles reaches 40%, excellent microwave absorption performance is exhibited. At this time, the pressed ring sample is dense in texture, high in mechanical strength, and has broad application prospects.
[0066] The above embodiments are the preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.
Claims
1. A hollow ferroferric oxide nanoparticle, characterized in that: The nanoparticles have an open hollow spherical structure, a particle size of 400nm to 1000nm, and an inner cavity diameter of 200nm to 500nm; the hollow ferroferric oxide nanoparticles contain micropores with a diameter of 10nm to 60nm.
2. A method for preparing hollow ferroferric oxide nanoparticles according to claim 1, characterized in that: The following steps are involved: 1) dispersing iron salt, sodium acetate, polyethylene glycol and polystyrene microspheres in ethylene glycol for solvothermal reaction to obtain magnetic nanoparticles; 2) The magnetic nanoparticles are washed with tetrahydrofuran for multiple times or calcined in a protective atmosphere to obtain hollow ferrosoferric oxide nanoparticles.
3. The method for preparing hollow ferroferric oxide nanoparticles according to claim 2, characterized in that: In step 1), the mass ratio of the iron salt, sodium acetate, polyethylene glycol and polystyrene microspheres is 1:1-2:0.2-0.7:0.02-0.
04.
4. The method for preparing hollow ferroferric oxide nanoparticles according to claim 2 or 3, characterized in that: The iron salt in step 1) is at least one of ferric chloride, ferric sulfate and ferric nitrate; the number average molecular weight of the polyethylene glycol in step 1) is 1800 g / mol to 2200 g / mol.
5. The method for preparing hollow ferroferric oxide nanoparticles according to claim 2 or 3, characterized in that: Step 1) The particle size of the polystyrene microspheres is 200nm to 500nm.
6. The method for preparing hollow ferroferric oxide nanoparticles according to claim 2 or 3, characterized in that: Step 1) The solvent thermal reaction is carried out at a temperature of 150° C. to 250° C., and the reaction time is 10 h to 14 h.
7. A microwave absorbing material, characterized in that: The composition comprises polypyrrole and the hollow ferroferric oxide nanoparticles according to claim 1.
8. The microwave absorbing material according to claim 7, characterized in that: The mass ratio of the polypyrrole to the hollow ferroferric oxide nanoparticles is 1:1-2.
9. The microwave absorbing material according to claim 7 or 8, characterized in that: The number average molecular weight of the polypyrrole is 1500 g / mol to 2000 g / mol.
10. A method for preparing a microwave absorbing material according to any one of claims 7 to 9, characterized in that: The following steps are involved: The microwave absorbing material is obtained by mixing polypyrrole and hollow ferroferric oxide nanoparticles.