CN115867013A - Porous carbon-based composite electromagnetic shielding material with high-communication network structure and preparation method thereof - Google Patents
Porous carbon-based composite electromagnetic shielding material with high-communication network structure and preparation method thereof Download PDFInfo
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Abstract
The invention relates to a porous carbon-based composite electromagnetic shielding material with a high-communication network structure and a preparation method thereof, belonging to the technical field of electromagnetic shielding. The composite electromagnetic shielding material is prepared from a porous carbon matrix and Co 3 O 4 Composite electromagnetic shielding material consisting of composite reinforcement of nano particles and CNTs, and Co 3 O 4 The nano particles and the CNTs are uniformly dispersed on a three-dimensional network structure of the porous carbon; soaking the hydrophilic porous carbon into a cobalt source solution containing CNTs, adding a NaOH aqueous solution, and subsequently growing in situ on a three-dimensional network structure of the porous carbon through solvothermal reaction to form Co 3 O 4 Nanoparticles, simultaneous CNTs with produced Co 3 O 4 And winding the nano particles with each other to prepare the composite electromagnetic shielding material. The invention introduces Co into the porous carbon at the same time 3 O 4 The nano particles and the CNTs can obviously improve the electromagnetic shielding performance of the porous carbon to ensure that the porous carbon meets the commercial standard requirement, and the preparation process is simple and easy to operateThe preparation method is easy for large-scale production and has good application prospect in the field of electromagnetic shielding materials.
Description
Technical Field
The invention relates to a porous carbon-based composite electromagnetic shielding material with a high-communication network structure and a preparation method thereof, belonging to the technical field of electromagnetic shielding.
Background
With the continuous development of social economy, information technology also enters an era of rapid development, and from the 1G era of mobile communication to the 5G era of information revolution nowadays, various integrated and intelligent electronic and electric equipment gradually burst into the fields of communication, traffic, medical appliances, household appliances and the like. Since the discovery of electromagnetic waves, great convenience is brought to the life of people, and meanwhile, a large amount of electromagnetic radiation is brought to cause electromagnetic pollution (EMI). Electromagnetic pollution can cause great threat to the environment and human body, and along with the gradual upgrade of electronic equipment, the requirements on sensitivity and precision are higher and higher, and the electromagnetic pollution is more sensitive to electromagnetic interference signals. Shielding is one of the most effective methods for resisting electromagnetic interference, excellent conductive performance and a perfect conductive network structure are the prerequisite conditions for obtaining high shielding efficiency of the electromagnetic shielding composite material, and effective multiple interface reflection absorption and the characteristics of the material are important factors for realizing high performance and controllable shielding performance of the electromagnetic shielding composite material. Therefore, the development of novel electromagnetic shielding materials with light weight, high efficiency, flexibility, corrosion resistance and low cost has become an important development direction in the field of electromagnetic shielding materials.
The high-communication network structure porous carbon is a novel porous carbon with a three-dimensional structure, belongs to a non-graphitizable carbon material, can keep high flexibility after high-temperature treatment, has certain strength, has the advantages of low density, high strength, good conductivity, corrosion resistance, easiness in processing and forming and the like, and is considered to be one of ideal candidate materials of next-generation electromagnetic shielding materials. However, the electromagnetic shielding performance of the porous carbon itself is general, and has a certain gap from the performance requirement of the electromagnetic shielding material. The method for preparing the porous carbon composite material by compounding the appropriate second-phase material with the porous carbon is a main means for improving the electromagnetic shielding performance of the porous carbon.
The most important advantages of metal and alloy materials are that the high conductivity of the material shows good electromagnetic wave attenuation capability, and the material is usually compounded with porous carbon in the form of a coating, but the metal has high density, low corrosion resistance, complex manufacturing process, high cost and poor wear resistance of the metal coating. The transition metal oxide has wide application prospect in the field of electromagnetic shielding because of the characteristics of high magnetic conductivity, low cost, good biocompatibility, high saturation magnetization and the like. Because the factors determining the electromagnetic shielding performance of the material are dielectric loss and magnetic loss, and the dielectric constant of the porous carbon is not high, most of the magnetic materials such as iron oxide and cobalt oxide which are independently adopted at present are used as reinforcements. The electromagnetic shielding performance of the porous carbon-based putrefaction composite material cannot reach the commercial standard, and the electromagnetic shielding performance of the porous carbon-based putrefaction composite material needs to be further improved to meet the commercial application requirements.
Disclosure of Invention
Aiming at the defects of the existing porous carbon-based composite electromagnetic shielding material, the invention provides a porous carbon-based composite electromagnetic shielding material with a high-communication network structure and a preparation method thereof 3 O 4 The nano particles and the CNTs can obviously improve the electromagnetic shielding performance so that the electromagnetic shielding performance reaches the commercial standard; in the preparation process, the porous carbon is subjected to hydrophilic treatment and the auxiliary effect of the CNTs (carbon nanotubes) can be utilized to ensure that Co can be subjected to hydrophilic treatment 3 O 4 The nano particles grow in situ on the porous carbon network structure, and can inhibit the continuous growth of the nano particles, so that Co is finally grown 3 O 4 The nano particles and the CNTs are mutually wound and uniformly dispersed.
The purpose of the invention is realized by the following technical scheme.
A porous carbon-based composite electromagnetic shielding material with high communication network structure is composed of a porous carbon matrix and Co 3 O 4 A composite electromagnetic shielding material consisting of nano particles and composite reinforcements of CNTs, and Co 3 O 4 The nano particles and the CNTs are uniformly dispersed on a three-dimensional network structure of the porous carbon.
Further, co 3 O 4 The nano particles and the CNTs are formed by in-situ growth of a cobalt source solution containing the CNTs on a three-dimensional network structure of the porous carbon 3 O 4 Nanoparticles, and Co produced 3 O 4 The nano particles and the CNTs are mutually wound so as to realize the uniform distribution of the nano particles and the CNTs on the porous carbon three-dimensional network structure;
wherein the cobalt source solution containing CNTs is prepared from Co (NO) 3 ) 2 ·6H 2 O, CNTs and ethanol.
Further, co (NO) 3 ) 2 ·6H 2 The concentration of O is 0.1-0.3 mol/L, the concentration of CNTs is 0.1-0.5 mg/mL, and the volume ratio of the cobalt source solution containing CNTs to the porous carbon is (6-3): 1.
A preparation method of a porous carbon-based composite electromagnetic shielding material with a high-communication network structure comprises the following steps:
(1) Carrying out hydrophilic treatment on the porous carbon;
(2) Soaking the hydrophilic porous carbon into a cobalt source solution containing CNTs, adding a NaOH aqueous solution, and uniformly mixing to form a reaction solution;
(3) Transferring the reaction solution into a reaction kettle for solvothermal reaction, and enabling the cobalt source to grow in situ on the three-dimensional network structure of the porous carbon to form Co 3 O 4 Nanoparticles, simultaneous CNTs with produced Co 3 O 4 The nanoparticles intertwine with each other, thereby realizing Co 3 O 4 The nano particles and the CNTs are uniformly distributed on the porous carbon three-dimensional network structure;
(4) After the solvothermal reaction is finished, collecting a reaction product, washing and drying to obtain Co 3 O 4 The invention relates to a nanoparticle/CNTs/porous carbon composite material, in particular to a porous carbon-based composite electromagnetic shielding material with a high communication network structure.
The porous carbon in the step (1) is preferably prepared by carbonizing melamine foam;
wherein, the carbonization process conditions are as follows: under the protection atmosphere of nitrogen or inert gas, firstly heating to 350-450 ℃ and preserving heat for 1-2 h, then continuing heating to 700-1000 ℃ and preserving heat for 1-2 h, and then cooling, wherein the heating rate and the cooling rate are both 5-15 ℃/min.
Preferably, the porous carbon is subjected to hydrophilic treatment by using a nitric acid solution, and the specific operation is as follows: putting the porous carbon into a nitric acid solution with the concentration of 2-3 mol/L, heating to 100-130 ℃, preserving heat for 1-3 h, taking out the porous carbon, cleaning and drying to finish the hydrophilic treatment of the porous carbon.
In the step (2), the cobalt source solution containing CNTs is prepared from Co (NO) 3 ) 2 ·6H 2 Prepared from O, CNTs and ethanol, co (NO) 3 ) 2 ·6H 2 The concentration of O is preferably 0.1 to 0.3mol/L, and the concentration of CNTs is preferably 0.1 to 0.5mg/mL. Accordingly, the volume ratio of the cobalt source solution containing CNTs to the porous carbon after hydrophilic treatment is preferably (6-3): 1, the volume ratio of the cobalt source solution containing CNTs to the NaOH aqueous solution is (12-13).
In the step (3), the temperature of the solvothermal reaction is 160-200 ℃ and the time is 8-18 h.
Has the beneficial effects that:
(1) The invention selects highly conductive CNTs and transition metal oxide Co 3 O 4 The magnetic nano particles are used as a composite reinforcement material, the flexible porous carbon is used as a matrix, and the electromagnetic shielding performance of the porous carbon-based composite material is effectively enhanced by improving the dielectric loss and the magnetic loss of the composite material, so that the flexible light electromagnetic shielding composite material with excellent electromagnetic shielding performance is obtained.
(2) In the solvothermal process, the porous carbon adsorbs more Co by utilizing the stronger adsorption force of the porous carbon 2+ These Co 2+ Become Co generated subsequently 3 O 4 The crystal nucleus of (1) is grown continuously to generate Co in situ 3 O 4 Nanoparticles, and the addition of CNTs suppresses Co 3 O 4 The continuous growth of nano-particles and the effective inhibition of Co with smaller particle size 3 O 4 Agglomeration of nanoparticles to achieve Co 3 O 4 The nanoparticles are uniformly attached to the network structure of the porous carbon.
(3) The porous carbon has light weight, large volume and strong hydrophobicity, and is used for ensuring subsequent Co 3 O 4 The nanoparticles can be well attached to grow, and need to be fed intoHydrophilic treatment is carried out, so that the reaction solution can be fully soaked. If the degree of hydrophilicity is insufficient, the porous carbon floats on the reaction solution and Co cannot be produced 3 O 4 The nano-particle/CNTs/porous carbon composite material can cause the three-dimensional structure of the porous carbon to be corroded and the structural integrity of the porous carbon to be damaged if the nano-particle/CNTs/porous carbon composite material is excessively hydrophilic.
(4) Because the porosity of the porous carbon is very high, the porous carbon is mixed with a reaction solution with a certain concentration for reaction according to a proper volume ratio, if the volume ratio is too large, the infiltration is incomplete, and if the volume ratio is too small, the introduction of a NaOH solution can greatly influence the subsequent Co 3 O 4 Reducing Co by nano-particle generation 3 O 4 The nano particles/CNTs/porous carbon composite material has electromagnetic shielding performance.
(5) The method has simple process, easy operation and easy large-scale production, and the prepared composite material has electromagnetic shielding performance meeting the commercial standard requirement and has good application prospect in the field of electromagnetic shielding materials.
Drawings
FIG. 1 shows Co prepared in example 1 3 O 4 nanoparticle/CNTs/porous carbon composite and Co prepared in example 2 3 O 4 X-ray diffraction (XRD) spectrum comparison diagram of the nano-particle/CNTs/porous carbon composite material.
Fig. 2 is a Scanning Electron Microscope (SEM) image of the porous carbon prepared in example 1.
Fig. 3 is an enlarged view of a portion of the labeled area in fig. 2.
FIG. 4 is Co prepared in example 1 3 O 4 Scanning electron microscope images of nanoparticle/CNTs/porous carbon composites.
Fig. 5 is an enlarged view of a portion of the labeled area in fig. 4.
FIG. 6 is Co prepared in example 1 3 O 4 Electromagnetic shielding performance curve diagram of nano-particle/CNTs/porous carbon composite material and porous carbon.
FIG. 7 shows Co prepared in comparative example 1 3 O 4 SEM images of different regions of the nanoparticle/porous carbon composite at different magnifications; wherein, the left pictureThe lower-magnification SEM image and the higher-magnification SEM image are shown on the right.
FIG. 8 shows Co prepared in comparative example 2 3 O 4 SEM images of different regions of the nanoparticle/porous carbon composite at different magnifications; wherein, the left image is a low-power SEM image, and the right image is a high-power SEM image.
Detailed Description
The present invention is further illustrated by the following detailed description, wherein the processes are conventional unless otherwise specified, and the starting materials are commercially available from a public source without further specification.
Example 1
(1) Firstly, respectively carrying out ultrasonic cleaning on melamine foam by using deionized water and absolute ethyl alcohol for 30min, then placing the melamine foam in an oven at 60 ℃ for drying for 12h, and transferring the melamine foam to a reactor filled with N 2 Carbonizing in the tubular furnace, heating to 400 ℃ at the heating rate of 5 ℃/min, preserving heat for 1h, then continuously heating to 1000 ℃ at the heating rate of 5 ℃/min, preserving heat for 1h, and cooling at the cooling rate of 5 ℃/min to prepare porous carbon;
(2) Adding 72mL of deionized water into 9mL of nitric acid with the mass fraction of 68%, and uniformly mixing to form a nitric acid solution with the concentration of 2.5 mol/L; immersing the porous carbon prepared in the step (1) into the nitric acid solution prepared in the step (2), transferring the solution into a polytetrafluoroethylene inner container, placing the inner container into a reaction kettle, heating the reaction kettle in an oven to 120 ℃, preserving heat for 1h, taking out the porous carbon, repeatedly cleaning the porous carbon by deionized water to be neutral, and then placing the porous carbon in an oven at 60 ℃ for drying for 12h to finish hydrophilic treatment of the porous carbon;
(3) 1.1646g of Co (NO) 3 ) 2 ·6H 2 Mixing O, 37mL of absolute ethyl alcohol and 8mg of CNTs, and ultrasonically oscillating for 1h to obtain a cobalt source solution uniformly containing the CNTs; soaking the hydrophilic-treated porous carbon obtained in the step (2) into a cobalt source solution containing CNTs, wherein the volume ratio of the hydrophilic-treated porous carbon to the cobalt source solution containing CNTs is 1;
(4) Transferring the reaction solution prepared in the step (3) into a polytetrafluoroethylene inner container, placing the polytetrafluoroethylene inner container into a reaction kettle, and carrying out solvothermal reaction in a vacuum drying oven at the reaction temperature of 180 ℃ for 12 hours;
(5) After the solvothermal reaction is finished, collecting a reaction product, repeatedly cleaning the reaction product by using ethanol, and then drying the reaction product in a 60 ℃ drying oven for 12 hours to obtain the porous carbon-based composite electromagnetic shielding material with the high-communication network structure, which is abbreviated as Co 3 O 4 nanoparticle/CNTs/porous carbon composites.
Phase analysis is carried out on the composite material prepared in the step (5), and as can be seen from an XRD spectrogram in figure 1, the composite material contains Co 3 O 4 。
The morphology of the porous carbon prepared in the step (1) is characterized, and as can be seen by combining fig. 2 and fig. 3, the cellular structure of the porous carbon is complete, the ligament structure connecting the cells is clear, and the porosity is high.
The morphology of the composite material prepared in step (5) is characterized, and as can be seen from FIGS. 4 and 5, co 3 O 4 The nano particles have no obvious agglomeration phenomenon and successfully grow on the surface of the porous carbon ligament, and simultaneously the CNTs and the Co have the same structure 3 O 4 The nano particles are mutually wound and uniformly dispersed.
Electromagnetic shielding performance tests are respectively carried out on the composite material prepared in the step (5) and the porous carbon prepared in the step (1), and the test result of figure 6 shows that the total shielding effectiveness of the composite material can reach 27dB at most in a wave band of 8.2-12.4 GHz, so that the composite material meets the commercial standard requirement (the total shielding effectiveness is required to be not lower than 20 dB), and is obviously superior to the shielding performance of the porous carbon.
Example 2
(1) Firstly, respectively carrying out ultrasonic cleaning on melamine foam by using deionized water and absolute ethyl alcohol for 30min, then placing the melamine foam in an oven at 60 ℃ for drying for 12h, and transferring the melamine foam to a reactor filled with N 2 Carbonizing in the tubular furnace, heating to 400 ℃ at the heating rate of 5 ℃/min, preserving heat for 1h, then continuously heating to 1000 ℃ at the heating rate of 5 ℃/min, preserving heat for 1h, and cooling at the cooling rate of 5 ℃/min to prepare porous carbon;
(2) Adding 144mL of deionized water into 18mL of nitric acid with the mass fraction of 68%, and uniformly mixing to form a nitric acid solution with the concentration of 2.5 mol/L; immersing the porous carbon prepared in the step (1) into the nitric acid solution prepared in the step (2), transferring the solution into a polytetrafluoroethylene inner container, placing the inner container into a reaction kettle, heating the reaction kettle in an oven to 100 ℃, preserving heat for 1h, taking out the porous carbon, repeatedly cleaning the porous carbon by deionized water to be neutral, and then placing the porous carbon in an oven at 60 ℃ for drying for 12h to finish hydrophilic treatment of the porous carbon;
(3) Mixing 3.4938g of Co (NO) 3 ) 2 ·6H 2 Mixing O, 111mL of absolute ethanol and 12mg of CNTs, and ultrasonically oscillating for 1h to obtain a cobalt source solution uniformly containing the CNTs; soaking the porous carbon subjected to hydrophilic treatment in the step (2) into a cobalt source solution containing CNTs, wherein the volume ratio of the porous carbon to the cobalt source solution containing CNTs is 1;
(4) Transferring the reaction solution prepared in the step (3) into a polytetrafluoroethylene inner container, placing the polytetrafluoroethylene inner container into a reaction kettle, and carrying out solvothermal reaction in a vacuum drying oven at the reaction temperature of 180 ℃ for 12 hours;
(5) After the solvothermal reaction is finished, collecting reaction products, repeatedly cleaning the reaction products by using ethanol, and then drying the reaction products in a 60 ℃ oven for 12 hours to obtain the porous carbon-based composite electromagnetic shielding material with the high-communication network structure, which is abbreviated as Co 3 O 4 nanoparticle/CNTs/porous carbon composites.
Phase analysis is carried out on the composite material prepared in the step (5), and as can be seen from an XRD spectrogram in figure 1, the composite material contains Co 3 O 4 。
Performing morphology characterization on the composite material prepared in the step (5), and obtaining Co according to the characterization result 3 O 4 The nano particles have no obvious agglomeration phenomenon and successfully grow on the surface of the porous carbon ligament, and simultaneously the CNTs and the Co have the same structure 3 O 4 The nano particles are mutually wound and uniformly dispersed.
And (4) performing an electromagnetic shielding performance test on the composite material prepared in the step (5), wherein the maximum total shielding effectiveness can reach 23dB when the composite material is tested in a wave band of 8.2-12.4 GHz, and the requirement of commercial standard is met.
Comparative example 1
(1) Firstly, the melamine foam is respectively ultrasonically cleaned by deionized water and absolute ethyl alcohol,cleaning for 30min, drying in 60 deg.C oven for 12 hr, and transferring to N-filled container 2 Carbonizing in the tubular furnace, heating to 400 ℃ at the heating rate of 5 ℃/min, preserving heat for 1h, then continuously heating to 1000 ℃ at the heating rate of 5 ℃/min, preserving heat for 1h, and cooling at the cooling rate of 5 ℃/min to prepare porous carbon;
(2) Adding 72mL of deionized water into 9mL of nitric acid with the mass fraction of 68%, and uniformly mixing to form a nitric acid solution with the concentration of 2.5 mol/L; immersing the porous carbon prepared in the step (1) into the nitric acid solution prepared in the step (2), transferring the solution into a polytetrafluoroethylene inner container, placing the inner container into a reaction kettle, heating the reaction kettle in an oven to 120 ℃, preserving heat for 1h, taking out the porous carbon, repeatedly cleaning the porous carbon by deionized water to be neutral, and then placing the porous carbon in an oven at 60 ℃ for drying for 12h to finish hydrophilic treatment of the porous carbon;
(3) 1.1646g of Co (NO) 3 ) 2 ·6H 2 Mixing O with 37mL of absolute ethyl alcohol, and carrying out ultrasonic oscillation for 1h to obtain a uniform cobalt source solution; immersing the porous carbon subjected to hydrophilic treatment in the step (2) into a cobalt source solution, wherein the volume ratio of the porous carbon to the cobalt source solution is 1;
(4) Transferring the reaction solution prepared in the step (3) into a polytetrafluoroethylene inner container, placing the polytetrafluoroethylene inner container into a reaction kettle, and carrying out solvothermal reaction in a vacuum drying oven at the reaction temperature of 180 ℃ for 12 hours;
(5) After the solvothermal reaction is finished, collecting reaction products, repeatedly cleaning the reaction products by using ethanol, and then drying the reaction products in a 60 ℃ oven for 12 hours to obtain the porous carbon-based composite electromagnetic shielding material with the high-communication network structure, which is abbreviated as Co 3 O 4 A nanoparticle/porous carbon composite.
The morphology of the composite material prepared in step (5) is characterized, and as can be seen from FIG. 7, co grows in situ on the porous carbon without adding CNTs 3 O 4 The nano particles are connected with each other to form a continuous coating layer which is uniformly coated on the porous carbon network structure, and not independent Co 3 O 4 The nano particles are uniformly dispersed on the porous carbon network structure.
And (4) performing an electromagnetic shielding performance test on the composite material prepared in the step (5), wherein the total shielding effectiveness can be up to 19dB at a wave band of 8.2-12.4 GHz, and the commercial standard requirement is not met.
Comparative example 2
(1) Firstly, respectively carrying out ultrasonic cleaning on melamine foam by using deionized water and absolute ethyl alcohol for 30min, then placing the melamine foam in an oven at 60 ℃ for drying for 12h, and transferring the melamine foam to a reactor filled with N 2 Carbonizing in the tubular furnace, heating to 400 ℃ at the heating rate of 5 ℃/min, preserving heat for 1h, then continuously heating to 1000 ℃ at the heating rate of 5 ℃/min, preserving heat for 1h, and cooling at the cooling rate of 5 ℃/min to prepare porous carbon;
(2) 1.1646g of Co (NO) 3 ) 2 ·6H 2 Mixing O with 37mL of absolute ethyl alcohol, and carrying out ultrasonic oscillation for 1h to obtain a uniform cobalt source solution; immersing the porous carbon prepared in the step (1) into a cobalt source solution, wherein the volume ratio of the porous carbon to the cobalt source solution is 1;
(3) Transferring the reaction solution prepared in the step (2) into a polytetrafluoroethylene inner container, placing the polytetrafluoroethylene inner container into a reaction kettle, and carrying out solvothermal reaction in a vacuum drying oven at the reaction temperature of 180 ℃ for 12 hours;
(4) After the solvothermal reaction is finished, collecting reaction products, repeatedly cleaning the reaction products by using ethanol, and then drying the reaction products in a 60 ℃ oven for 12 hours to obtain the porous carbon-based composite electromagnetic shielding material with the high-communication network structure, which is abbreviated as Co 3 O 4 Nanoparticle/porous carbon composites.
The morphology of the composite material prepared in step (4) is characterized, and it can be seen from FIG. 8 that Co generated by the solvothermal reaction is generated subsequently when the porous carbon is not subjected to the hydrophilic treatment 3 O 4 The nano particles can not be effectively attached to the network structure of the porous carbon, and Co loaded on the network structure of the porous carbon at the moment 3 O 4 The amount of nanoparticles is very small and Co produced 3 O 4 Is irregular shaped nano-particles (such as flakes, needles, irregular spheres, etc.).
Comparative example 3
(1) Firstly, respectively carrying out ultrasonic cleaning on melamine foam by using deionized water and absolute ethyl alcohol for 30min, then placing the melamine foam in an oven at 60 ℃ for drying for 12h, and transferring the melamine foam to a reactor filled with N 2 Carbonizing in the tubular furnace, heating to 400 ℃ at the heating rate of 5 ℃/min, preserving heat for 1h, then continuously heating to 1000 ℃ at the heating rate of 5 ℃/min, preserving heat for 1h, and cooling at the cooling rate of 5 ℃/min to prepare porous carbon;
(2) Adding 72mL of deionized water into 9mL of nitric acid with the mass fraction of 68%, and uniformly mixing to form a nitric acid solution with the concentration of 2.5 mol/L; immersing the porous carbon prepared in the step (1) into the nitric acid solution prepared in the step (2), transferring the solution into a polytetrafluoroethylene inner container, placing the inner container into a reaction kettle, heating the reaction kettle in an oven to 120 ℃, preserving heat for 1h, taking out the porous carbon, repeatedly cleaning the porous carbon by deionized water to be neutral, and then placing the porous carbon in an oven at 60 ℃ for drying for 12h to finish hydrophilic treatment of the porous carbon;
(3) 1.1646g of Co (NO) 3 ) 2 ·6H 2 Mixing O with 37mL of absolute ethyl alcohol, and carrying out ultrasonic oscillation for 1h to obtain a uniform cobalt source solution; immersing the porous carbon subjected to hydrophilic treatment in the step (2) into a cobalt source solution, wherein the volume ratio of the porous carbon to the cobalt source solution is 1, simultaneously adding 3mL of NaOH aqueous solution with the concentration of 0.2mol/L, and then carrying out ultrasonic treatment for 30min to obtain a reaction solution;
(4) Transferring the reaction solution prepared in the step (3) into a polytetrafluoroethylene inner container, placing the polytetrafluoroethylene inner container into a reaction kettle, and carrying out solvothermal reaction in a vacuum drying oven at the reaction temperature of 180 ℃ for 12 hours;
(5) After the solvothermal reaction is finished, collecting reaction products, repeatedly cleaning the reaction products by using ethanol, and then drying the reaction products in a 60 ℃ oven for 12 hours to obtain the porous carbon-based composite electromagnetic shielding material with the high-communication network structure, which is abbreviated as Co 3 O 4 Nanoparticle/porous carbon composites.
And (5) performing morphology characterization on the composite material prepared in the step (5), wherein according to characterization results, the wetting is incomplete when the volume ratio of the hydrophilic porous carbon to the cobalt source solution is too large, so that Co generated by the solvothermal reaction subsequently is caused 3 O 4 The nano particles can only be localized on the network structure of the porous carbonPartial loading, and uniform loading on the porous carbon network structure cannot be achieved.
In summary, the above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (9)
1. The utility model provides a high UNICOM network structure porous carbon base composite electromagnetic shield material which characterized in that: is prepared from porous carbon matrix and Co 3 O 4 Composite electromagnetic shielding material consisting of composite reinforcement of nano particles and CNTs, and Co 3 O 4 The nano particles and the CNTs are uniformly dispersed on a three-dimensional network structure of the porous carbon.
2. The high-communication network structure porous carbon-based composite electromagnetic shielding material according to claim 1, characterized in that: co 3 O 4 The nano particles and the CNTs are formed by in-situ growth of a cobalt source solution containing the CNTs on a three-dimensional network structure of the porous carbon 3 O 4 Nanoparticles, and Co produced 3 O 4 The nano particles and the CNTs are mutually wound so as to realize the uniform distribution of the nano particles and the CNTs on the porous carbon three-dimensional network structure;
wherein the cobalt source solution containing CNTs is prepared from Co (NO) 3 ) 2 ·6H 2 O, CNTs and ethanol.
3. The high-communication network structure porous carbon-based composite electromagnetic shielding material according to claim 2, characterized in that: co (NO) 3 ) 2 ·6H 2 The concentration of O is 0.1-0.3 mol/L, the concentration of CNTs is 0.1-0.5 mg/mL, and the volume ratio of the cobalt source solution containing CNTs to the porous carbon is (6-3): 1.
4. A preparation method of the porous carbon-based composite electromagnetic shielding material with the high communication network structure based on claim 1 or 2 is characterized in that: the method comprises the following steps:
(1) Carrying out hydrophilic treatment on the porous carbon;
(2) Soaking the hydrophilic porous carbon into a cobalt source solution containing CNTs, adding a NaOH aqueous solution, and uniformly mixing to form a reaction solution;
(3) Transferring the reaction solution into a reaction kettle for solvothermal reaction, and enabling the cobalt source to grow in situ on the three-dimensional network structure of the porous carbon to form Co 3 O 4 Nanoparticles, simultaneous CNTs with produced Co 3 O 4 The nanoparticles intertwine with each other, thereby realizing Co 3 O 4 The nano particles and the CNTs are uniformly distributed on the porous carbon three-dimensional network structure;
(4) After the solvothermal reaction is finished, collecting a reaction product, washing and drying to obtain Co 3 O 4 The nano-particle/CNTs/porous carbon composite material is the porous carbon-based composite electromagnetic shielding material with the high-communication network structure;
wherein, the cobalt source solution containing CNTs in the step (2) is prepared from Co (NO) 3 ) 2 ·6H 2 O, CNTs and ethanol.
5. The preparation method of the porous carbon-based composite electromagnetic shielding material with the high communication network structure according to claim 4, characterized in that: the porous carbon in the step (1) is prepared by carbonizing melamine foam;
wherein, the carbonization process conditions are as follows: under the protection atmosphere of nitrogen or inert gas, firstly heating to 350-450 ℃ and preserving heat for 1-2 h, then continuing heating to 700-1000 ℃ and preserving heat for 1-2 h, and then cooling, wherein the heating rate and the cooling rate are both 5-15 ℃/min.
6. The preparation method of the porous carbon-based composite electromagnetic shielding material with the high communication network structure according to claim 4, characterized in that: in the step (1), a nitric acid solution is adopted to carry out hydrophilic treatment on the porous carbon, and the specific operation is as follows: putting the porous carbon into a nitric acid solution with the concentration of 2-3 mol/L, heating to 100-130 ℃, preserving heat for 1-3 h, taking out the porous carbon, cleaning and drying to finish the hydrophilic treatment of the porous carbon.
7. The preparation method of the porous carbon-based composite electromagnetic shielding material with the high communication network structure according to claim 4, characterized in that: in the cobalt source solution containing CNTs in the step (2), co (NO) 3 ) 2 ·6H 2 The concentration of O is 0.1-0.3 mol/L, and the concentration of CNTs is 0.1-0.5 mg/mL.
8. The preparation method of the porous carbon-based composite electromagnetic shielding material with the high communication network structure according to claim 7, characterized in that: in the step (2), the volume ratio of the cobalt source solution containing CNTs to the porous carbon after hydrophilic treatment is (6-3) to 1, the volume ratio of the cobalt source solution containing CNTs to an NaOH aqueous solution is (12-13).
9. The preparation method of the porous carbon-based composite electromagnetic shielding material with the high communication network structure according to claim 4, characterized in that: in the step (3), the temperature of the solvothermal reaction is 160-200 ℃ and the time is 8-18 h.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN118019311A (en) * | 2024-01-26 | 2024-05-10 | 黑龙江工程学院 | Preparation method of electromagnetic shielding material with photo-electromagnetic performance |
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