Preparation method of nano porous carbon coated magnetic nanoparticle compound
阅读说明：本技术 一种纳米多孔碳包覆磁性纳米粒子复合物的制备方法 (Preparation method of nano porous carbon coated magnetic nanoparticle compound ) 是由 陈平 朱晓宇 邱红芳 于 2021-08-09 设计创作，主要内容包括：本发明提供一种纳米多孔碳包覆磁性纳米粒子复合物的制备方法,属于复合材料技术领域。首先,合成石墨相氮化碳,将其与镁粉混合后高温碳化,产物经盐酸洗涤得到纳米多孔碳；其次,将铁、钴、镍的金属盐溶于甲醇并加入纳米多孔碳混合烘干；最后,将混合物高温煅烧,得到纳米多孔碳包覆纳米粒子复合吸波材料。本发明利用两步法纳米多孔碳包覆磁性纳米粒子复合吸波材料,展现了良好的电磁波吸收能力；制备方法操作简单,产物具有良好的电磁参数以及电磁波吸收能力。(The invention provides a preparation method of a nano porous carbon coated magnetic nanoparticle compound, belonging to the technical field of composite materials. Firstly, synthesizing graphite-phase carbon nitride, mixing the graphite-phase carbon nitride with magnesium powder, then carbonizing at high temperature, and washing a product with hydrochloric acid to obtain nano porous carbon; secondly, dissolving metal salts of iron, cobalt and nickel in methanol, adding nano porous carbon, mixing and drying; and finally, calcining the mixture at high temperature to obtain the nano porous carbon coated nano particle composite wave-absorbing material. According to the invention, the magnetic nanoparticle composite wave-absorbing material is coated by the nano porous carbon by a two-step method, so that good electromagnetic wave absorption capability is shown; the preparation method is simple to operate, and the product has good electromagnetic parameters and electromagnetic wave absorption capacity.)
1. A preparation method of a nano porous carbon coated magnetic nanoparticle compound is characterized by comprising the following steps:
1) by calcining melamine C at high temperature3N6H6Preparation of g-C3N4As intermediate 1; uniformly mixing the intermediate 1 and magnesium powder, and then calcining at high temperature, wherein the calcining temperature is 700-900 ℃, and the calcining time is 1-3 h; washing the obtained product with hydrochloric acid, washing the product with deionized water to be neutral, filtering and drying to obtain nano porous carbon, namely an intermediate 2; the g to C3N4The mass ratio of the magnesium to the magnesium is 1: 0.5-3.5;
2) dissolving metal salt in methanol to prepare a solution, adding the intermediate 2 nano porous carbon, magnetically stirring, and drying the mixed solution to obtain a metal salt loaded nano porous carbon composite, namely an intermediate 3; the mass ratio of C in the intermediate 3 to the metal salt is controlled to be 1: 0.2 to 2;
3) and placing the intermediate 3 powder in a tubular furnace, and performing high-temperature calcination in an inert atmosphere at the calcination temperature of 300-700 ℃ for 1-4h to obtain the nano porous carbon coated magnetic nanoparticle compound.
2. The method for preparing the nanoporous carbon-coated magnetic nanoparticle composite according to claim 1, wherein the step 1) is used for preparing g-C3N4The process comprises the following steps: the melamine is placed in a tubular furnace and calcined in air at high temperature, wherein the calcination temperature is 480-650 ℃, and the optimal temperature is 550 ℃.
3. The method for preparing the nanoporous carbon-coated magnetic nanoparticle composite according to claim 1, wherein the calcination temperature in the step 1) is preferably 750 ℃ and the calcination time is preferably 2 h.
4. The method for preparing the nanoporous carbon-coated magnetic nanoparticle composite according to claim 1, wherein the mass ratio of the nanoporous carbon and the metal salt in the step 2) is preferably 3: 1.
5. the method according to claim 1, wherein the metal salt comprises one of ferric acetylacetonate, ferrous acetylacetonate, nickel acetylacetonate, cobalt nitrate, ferric nitrate, nickel nitrate, ferric acetate, cobalt acetate, nickel acetate, ferric chloride, nickel chloride, cobalt chloride, and combinations thereof.
6. The method for preparing the nanoporous carbon-coated magnetic nanoparticle composite according to claim 1, wherein the calcination temperature in the step 3) is preferably 500 ℃ and the calcination time is preferably 2 h.
Technical Field
The invention belongs to the technical field of composite materials, and relates to a preparation method of a nano porous carbon coated magnetic nanoparticle composite wave-absorbing material.
Background
Nowadays, with the rapid development of electronic communication technology, the dependence of human life on various electronic products is increasingly strengthened, great convenience is brought to daily life of people, and serious electromagnetic pollution is brought. The long-term exposure to excessive electromagnetic radiation can cause irreversible damage to the immune system, nervous system and the like of the human body, and seriously threatens the physical and psychological health of human beings. In addition, in the fields of naval vessel manufacturing, electromagnetic stealth of warplanes and the like, the preparation of efficient electromagnetic wave absorbing materials is also a hot problem of research.
The carbon material has low cost and good conductivity, but the high conductivity causes the carbon material with single component to have poor impedance matching performance and can not fully absorb electromagnetic waves. Therefore, the composite wave-absorbing material prepared from the novel magnetic particles and the carbon material gradually becomes the mainstream direction. As the nano porous carbon coated magnetic particle composite wave absorption material with a special structure, the magnetic particles with good impedance matching performance are introduced, so that electromagnetic waves can enter the material, the reflection of the electromagnetic waves is reduced, the magnetic loss of the material is increased, and good electromagnetic absorption is realized.
Therefore, the invention designs and synthesizes the nano porous carbon coated magnetic nanoparticle composite for electromagnetic wave absorption.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a simple and feasible method for preparing a nano porous carbon coated magnetic nanoparticle compound.
In order to achieve the purpose, the invention adopts the technical scheme that:
a preparation method of a nano porous carbon coated magnetic nanoparticle compound is characterized in that g-C is reduced by magnesium powder3N4And finally, calcining the intermediate 3 at high temperature to obtain the nano porous carbon coated magnetic nanoparticles. The method specifically comprises the following steps:
1) by calcining melamine (C) at high temperature3N6H6) Preparation of g-C3N4As intermediate 1; and uniformly mixing the intermediate 1 and magnesium powder, calcining at high temperature, washing the obtained product with hydrochloric acid, washing the product with deionized water to be neutral, filtering and drying to obtain the nanoporous carbon, namely the intermediate 2. The g to C3N4The mass ratio of the magnesium to the magnesium is 1: 0.5-3.5, the calcination temperature is 700-Is 1-3 h.
2) Dissolving metal salt in methanol to prepare a solution, adding the intermediate 2 nano porous carbon, magnetically stirring for 30min, and drying the mixed solution to obtain the nano porous carbon composite loaded with the metal salt, namely the intermediate 3. The mass ratio of C in the intermediate 3 to the metal salt is controlled to be 1: 0.2-2.
3) And placing the intermediate 3 powder in a tubular furnace, and performing high-temperature calcination in an inert atmosphere at the calcination temperature of 300-700 ℃ for 1-4h to obtain the nano porous carbon coated magnetic nanoparticle compound.
Further, said step 1) preparing g-C3N4The process comprises the following steps: placing melamine in a tubular furnace, and calcining at high temperature in air, wherein the calcining temperature is 480-650 ℃, and the optimal temperature is 550 ℃; the calcination time is 1-5h, and the optimal time is 3 h.
Further, the calcination temperature in the step 1) is preferably 750 ℃, and the calcination time is preferably 2 h.
Further, the mass ratio of the nanoporous carbon to the metal salt in the step 2) is preferably 3: 1.
further, the metal salt includes one of ferric acetylacetonate, ferrous acetylacetonate, nickel acetylacetonate, cobalt nitrate, ferric nitrate, nickel nitrate, ferric acetate, cobalt acetate, nickel acetate, ferric chloride, nickel chloride, cobalt chloride and combinations thereof.
Further, the calcining temperature in the step 3) is preferably 500 ℃, and the calcining time is preferably 2 hours.
The invention has the beneficial effects that:
in the preparation process, the invention utilizes magnesium and g-C3N4Calcining, and washing a product with hydrochloric acid to obtain nano porous carbon; the porous channel of the nanoporous carbon is used for adsorbing metal salt in the methanol solution of the metal salt, and finally the metal salt is reduced into magnetic particles through high temperature, so that the obtained product is the composite of the nanoporous carbon coated magnetic nanoparticles.
Scanning electron microscopy, Raman spectroscopy and X-ray diffraction show that the nano-porous carbon-coated magnetic nanoparticles prepared by the method are consistent in structure with expectations. The early test of the network vector analyzer and the later simulation of matlab can well prove that the network vector analyzer has good wave absorbing performance, and the feasibility of the method is demonstrated. The prepared nano porous carbon-coated magnetic nanoparticles have good impedance matching and attenuation properties, and can sufficiently attenuate electromagnetic waves.
Drawings
FIG. 1 is C @ Fe3O4-1 scanning electron micrograph of composite wave-absorbing material:
FIG. 2 is C @ Fe3O4-1 raman spectrum of composite wave-absorbing material:
FIG. 3 is C @ Fe3O4-1X-ray diffraction spectrum Raman spectrum of the composite wave-absorbing material:
FIG. 4 is C @ Fe3O4-1 reflection loss curve of the composite wave-absorbing material.
Detailed Description
The present invention is further illustrated by the following specific examples.
Example 1 nanoporous carbon coated magnetic Fe3O4Composite wave-absorbing particle C @ Fe3O4-1 preparation method:
preparing nanoporous carbon C-1:
8.0g of melamine was calcined in a tube furnace at 550 ℃ for 3h in an air atmosphere. 2.0g g-C3N4And uniformly mixing with 4.0g of magnesium powder, calcining for 2 hours at 750 ℃ in an argon atmosphere, washing the product to be neutral by using hydrochloric acid and deionized water, filtering and drying to obtain the product, namely the nanoporous carbon C-1.
(di) C @ Fe (acc)3-1 preparation:
3.0g of the nanoporous carbon obtained above was added to a solution of 1.0g of Fe (acc)3Stirring with 40ml of methanol solution magnetically for 30min, and drying the obtained mixed solution to obtain powder C @ Fe (acc)3-1。
(III) C @ Fe3O4-1 preparation:
mixing C @ Fe (acc)3-1, placing the mixture in a tube furnace, calcining the mixture for 2 hours at 500 ℃ in an argon atmosphere to obtain the nano porous carbon coatingMagnetic Fe3O4Composite wave-absorbing particle C @ Fe3O4-1。
(IV) the detection results are as follows:
FIG. 1 is C @ Fe3O4-1 scanning electron micrograph. As can be seen from the figure, a large number of particles are present on the surface of the porous carbon;
FIG. 2 is C @ Fe3O4-1 Raman spectrum. As can be seen from the figure, the final product C @ Fe of the D peak and the G peak of the graphite carbon obviously exists3O4-1 contains graphitic carbon;
FIG. 3 is C @ Fe3O4X-ray diffraction Pattern of-1, 26.10The diffraction peak at (A) is that of graphitic carbon, 46.60And 53.80Is Fe3O4The diffraction peak of (1). Description of C @ Fe3O4The composition of-1 is graphitic carbon with Fe3O4。
FIG. 4 is C @ Fe3O4-1, wherein the composite wave-absorbing material C @ Fe can be seen in the figure3O4-1 at a frequency of 7.37GHz the reflection loss is at least-73.93 dB, the effective absorption bandwidth is 5.44GHz, and the thickness is 1.9 mm.
Example 2 nanoporous carbon coated magnetic Fe3O4Composite wave-absorbing particle C @ Fe3O4-2 preparation method:
preparing nanoporous carbon C-2:
8.0g of melamine was calcined in a tube furnace at 480 ℃ for 1h in an air atmosphere. 2.0g g-C3N4And uniformly mixing with 1.0g of magnesium powder, calcining for 3 hours at 800 ℃ in an argon atmosphere, washing the product to be neutral by using hydrochloric acid and deionized water, filtering and drying to obtain the product, namely the nanoporous carbon C-2.
(di) C @ Fe (acc)3-2 preparation:
1.5g of the nanoporous carbon obtained above was added to a solution of 3.0g of Fe (acc)3Stirring with 40ml of methanol solution magnetically for 30min, and drying the obtained mixed solution to obtain powder C @ Fe (acc)3-2。
(III) C @ Fe3O4-2 preparation:
mixing C @ Fe (acc)3-2, calcining the mixture for 4 hours at 700 ℃ in a tubular furnace in an argon atmosphere to obtain the nano porous carbon coated magnetic Fe3O4Composite wave-absorbing particle C @ Fe3O4-2。
Example 3 nanoporous carbon coated magnetic Fe3O4Composite wave-absorbing particle C @ Fe3O4-3 preparation method:
preparing nanoporous carbon C-3:
8.0g of melamine was calcined in a tube furnace at 600 ℃ for 5h in an air atmosphere. 1.0g g-C3N4And uniformly mixing with 3.0g of magnesium powder, calcining for 1h at 700 ℃ in an argon atmosphere, washing the product to be neutral by using hydrochloric acid and deionized water, filtering and drying to obtain the product, namely the nanoporous carbon C-3.
(di) C @ Fe (acc)3-3 preparation:
2.0g of the nanoporous carbon obtained above was added to a solution of 1.0g of Fe (acc)3Stirring with 40ml of methanol solution magnetically for 30min, and drying the obtained mixed solution to obtain powder C @ Fe (acc)3-3。
(III) C @ Fe3O4-3 preparation:
mixing C @ Fe (acc)3-3, calcining the mixture for 1h at 400 ℃ in a tubular furnace in an argon atmosphere to obtain the nano porous carbon coated magnetic Fe3O4Composite wave-absorbing particle C @ Fe3O4-3。
Example 4 nanoporous carbon coated magnetic Fe3O4Composite wave-absorbing particle C @ Fe3O4-4 preparation method:
preparing nanoporous carbon C-4:
8.0g of melamine were calcined in a tube furnace at 650 ℃ for 4h in an air atmosphere. 1.0g g-C3N4And uniformly mixing with 3.5g of magnesium powder, calcining for 2h at 900 ℃ in an argon atmosphere, washing the product to be neutral by using hydrochloric acid and deionized water, filtering and drying to obtain the product, namely the nano porous carbon.
(di) C @ Fe (acc)3-4 preparation:
2.0g of the nanoporous carbon obtained above was added to a solution of 0.4g of Fe (acc)3Stirring with 40ml of methanol solution magnetically for 30min, and drying the obtained mixed solution to obtain powder C @ Fe (acc)3-4。
(III) C @ Fe3O4-4 preparation:
mixing C @ Fe (acc)3-4, placing the mixture in a tube furnace, calcining the mixture for 1.5 hours at 300 ℃ in an argon atmosphere to obtain the nano porous carbon coated magnetic Fe3O4Composite wave-absorbing particle C @ Fe3O4-4。
Example 5 nanoporous carbon coated magnetic Fe3O4Composite wave-absorbing particle C @ Fe3O4-5 preparation method:
preparing nanoporous carbon C-5:
8.0g of melamine was calcined in a tube furnace at 500 ℃ for 2h in an air atmosphere. 2.0g g-C3N4And uniformly mixing with 2.0g of magnesium powder, calcining for 2h at 850 ℃ in an argon atmosphere, washing the product to be neutral by using hydrochloric acid and deionized water, filtering and drying to obtain the product, namely the nanoporous carbon C-5.
(di) C @ Fe (acc)3-5 preparation:
2.0g of the nanoporous carbon obtained above was added to a solution of 2.5g of Fe (acc)3Stirring with 40ml of methanol solution magnetically for 30min, and drying the obtained mixed solution to obtain powder C @ Fe (acc)3-5。
(III) C @ Fe3O4-5 preparation:
mixing C @ Fe (acc)3-5, placing the mixture in a tube furnace, calcining the mixture for 3 hours at the temperature of 600 ℃ in the argon atmosphere to obtain the nano porous carbon coated magnetic Fe3O4Composite wave-absorbing particle C @ Fe3O4-5。
The above-mentioned embodiments only express the embodiments of the present invention, but not should be understood as the limitation of the scope of the invention patent, it should be noted that, for those skilled in the art, many variations and modifications can be made without departing from the concept of the present invention, and these all fall into the protection scope of the present invention.