CN115942728B - Spindle-shaped Co@C-Mxene electromagnetic shielding material and preparation method thereof - Google Patents
Spindle-shaped Co@C-Mxene electromagnetic shielding material and preparation method thereof Download PDFInfo
- Publication number
- CN115942728B CN115942728B CN202211422614.XA CN202211422614A CN115942728B CN 115942728 B CN115942728 B CN 115942728B CN 202211422614 A CN202211422614 A CN 202211422614A CN 115942728 B CN115942728 B CN 115942728B
- Authority
- CN
- China
- Prior art keywords
- mxene
- electromagnetic shielding
- composite material
- shielding material
- spindle
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A30/00—Adapting or protecting infrastructure or their operation
Landscapes
- Inorganic Compounds Of Heavy Metals (AREA)
- Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Abstract
The application provides a spindle-shaped Co@C-MXene electromagnetic shielding material and a preparation method thereof, and relates to the field of electromagnetic shielding material preparation, wherein the method comprises the following steps: preparing a Co@C composite material by taking ZIF67 as a precursor; ultrasonically dispersing the Co@C pretreated by the oxidized dodecyl dimethylamine into deionized water to obtain Co@C suspension; after that, the Co@C suspension is dripped into Ti 3 C 2 T x Stirring in an MXene aqueous solution for 1-2 h in an ice bath to obtain Co@C-MXene composite material suspension; and freeze-drying the Co@C-MXene composite material suspension to obtain the Co@C-MXene electromagnetic shielding material. The Co@C-MXene electromagnetic shielding material prepared by the method has electromagnetic shielding performance higher than 40dB and up to 120dB in a 5-8.5GHz microwave frequency band.
Description
Technical Field
The application belongs to the technical field of electromagnetic shielding material preparation, and particularly relates to a spindle-shaped Co@C-Mxene electromagnetic shielding material and a preparation method thereof.
Background
With the development of modern radio technology and the popularization of electronic equipment, electromagnetic radiation is increasingly serious, and the normal operation of electronic elements is interfered, so that the electronic equipment is failed, and meanwhile, potential harm is caused to human health. Development of high-performance electromagnetic shielding materials is an effective way to prevent electromagnetic pollution. The traditional electromagnetic shielding materials mostly use metal materials such as copper, aluminum and the like, have large specific gravity and poor corrosion resistance, and limit the application of the electromagnetic shielding materials in the fields of movable equipment and the like. Therefore, development of lightweight electromagnetic shielding materials is being pursued. In recent years, development of two-dimensional nano materials such as graphene, MXene, black phosphorus and the like has promoted development of electromagnetic protection technology.
However, the preparation process of the MXene-based composite electromagnetic shielding material is generally complicated, the electromagnetic shielding mechanism of the sample is single, and the performance is required to be further improved. Meanwhile, the MXene material is easy to self-stack and oxidize and degrade, and further development of the MXene material is severely restricted. Therefore, there is an urgent need to develop a general method for preparing an electromagnetic shielding material based on high-efficiency MXene to obtain an electromagnetic shielding material that is lightweight, high-efficiency, and stable.
Disclosure of Invention
In order to solve the technical problems, the application provides a spindle-shaped Co@C-Mxene electromagnetic shielding material and a preparation method thereof, wherein Co@C is used as an insert, and self stacking of-Mxene can be avoided.
The application discloses a preparation method of a spindle-shaped Co@C-Mxene electromagnetic shielding material. The method comprises the following steps:
step S1, preparing a Co@C composite material by taking ZIF67 as a precursor and adopting a thermal shock method;
s2, ultrasonically dispersing the Co@C composite material pretreated by the oxidized dodecyl dimethylamine in deionized water to obtain the composite material with the concentration of 2-3 mg.ml -1 Co@c suspension of (c);
step S3, dripping a certain volume of the Co@C suspension liquid into a solution with the concentration of 1-2 mg.ml -1 Ti of (2) 3 C 2 T x Stirring in an MXene aqueous solution for 1-2 h in an ice bath to obtain Co@C-MXene composite material suspension;
and S4, freeze-drying the Co@C-MXene composite material suspension in the step S3 to obtain the Co@C-MXene electromagnetic shielding material.
According to the method of the first aspect of the present application, in the step S1, the heat shock method is specifically performed as follows:
two leads are led out from the positive electrode and the negative electrode of the direct current power supply by using the direct current power supply as an energy supply power supply and are respectively connected with two carbon cloths aligned up and down to form a loop, then the ZIF67 is arranged between the two carbon cloths, and thermal shock treatment is carried out on the ZIF67 under the inert gas atmosphere to obtain a Co@C composite material;
the thermal shock treatment is carried out according to the processes of 1-5 s of power-on, 2-5 s of power-off and 1-5 s of power-on; the output temperature of the thermal shock is 800-900 ℃.
According to the method of the first aspect of the present application, in the step S2, the preprocessing is specifically as follows:
dispersing 20mg of the Co@C composite material in 30ml of a solution with the concentration of 8-20 mg.ml -1 Is soaked in the aqueous solution of the dodecyl dimethylamine oxide for 2 to 3 hours and is centrifugally treated for standby.
According to the method of the first aspect of the application, in said step S3, the volume of said co@c suspension is between 5 and 10ml.
According to the method of the first aspect of the present application, in the step S3, the Ti is 3 C 2 T x The volume of the MXene aqueous solution is 50-55 ml.
According to the method of the first aspect of the present application, the step S4 includes:
s41, freezing the Co@C-MXene composite material suspension by utilizing liquid nitrogen to obtain a solid Co@C-MXene composite material;
step S42, freeze-drying the solid Co@C-MXene composite material in the step S41 for 20-24 hours by using a freeze dryer, and sublimating liquid molecules to obtain a Co@C-MXene electromagnetic shielding material;
wherein the temperature of the freeze drying is lower than-70 ℃ and the pressure is less than 0.001Pa.
According to the method of the first aspect of the application, the ZIF67 is prepared as follows:
0.1 to 0.3g of Co (NO) 3 ) 2 ·6H 2 O is fully dissolved in 30-50 ml of methanol to be used as solution A; fully dissolving 1-3 g of 2-methylimidazole in 30-50 ml of methanol to obtain a solution B; then, the solution B is added into the solution A rapidly, stirred for 24 hours at room temperature and then centrifugally dried to obtain the ZIF67.
According to the method of the first aspect of the application, the inert gas is argon.
The application also discloses a spindle-shaped Co@C-MXene electromagnetic shielding material prepared by the preparation method; the electromagnetic shielding performance of the spindle-shaped Co@C-MXene electromagnetic shielding material in the 5-8.5GHz microwave frequency band is higher than 40dB.
In summary, the scheme provided by the application has the following technical effects:
the application creatively introduces the magnetic material and the dielectric material Co@C into the MXene two-dimensional material, thereby effectively improving the electromagnetic shielding performance of the composite material. According to the application, co@C is soaked in a dodecyl dimethylamine solution with a certain concentration, and the surface of Co@C is adsorbed by the pretreated surface of Co@C which is a two-dimensional material with a larger specific surface area, so that the surface of Co@C has positive electricity. On the basis, the pretreated Co@C is dispersed in an MXene aqueous solution at a low temperature, and the surface of the MXene material is electronegative, so that the pretreated Co@C is easy to combine with the Co@C through electrostatic adsorption. In addition, the MXene material has larger specific surface area and surface vacancies, so that the MXene material has stronger surface adsorptivity, and the effective adsorption of Co@C on MXene can be realized.
In addition, after the Co@C-MXene composite material suspension is subjected to freeze drying treatment, the two ends of Co@C particles are sharper, the spindle shape is more obvious, and electrons with higher density can be excited to incident electromagnetic waves, so that the Co@C-MXene electromagnetic shielding material has stronger shielding effect on the electromagnetic waves. The Co@C-MXene electromagnetic shielding material prepared by the method has the electromagnetic shielding performance higher than 40dB and up to 120dB in the 5-8.5GHz microwave frequency band, and has the characteristics of light weight and good stability.
In addition, the Co@C-MXene electromagnetic shielding material prepared by the freeze-drying method is reliable in repeatability, can realize batch production of the material, and is suitable for industrial production.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present application, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of a method for preparing a spindle-shaped Co@C-MXene electromagnetic shielding material according to an embodiment of the application;
FIG. 2 (a) is a transmission electron micrograph of ZIF-67;
FIG. 2 (b) is a transmission electron micrograph of Co@C;
FIG. 2 (c) is a transmission electron micrograph of the Co@C-MXene electromagnetic shielding material prepared in the specific example 1 according to the present application;
FIG. 3 is an X-ray photoelectron spectrum of a Co@C-MXene electromagnetic shielding material according to specific embodiment 1 of the present application;
FIG. 4 shows the results of electromagnetic shielding performance tests at the microwave frequency range of 5.5-8.5GHz for Co@C, MXene and Co@C-MXene electromagnetic shielding materials according to specific embodiment 1 of the application.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present application more apparent, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application, and it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments of the present application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
The application discloses a preparation method of a spindle-shaped Co@C-MXene electromagnetic shielding material. FIG. 1 is a flow chart of a method for preparing a spindle-shaped Co@C-MXene electromagnetic shielding material according to an embodiment of the application. As shown in fig. 1, the method includes:
and S1, preparing the Co@C composite material by taking ZIF67 as a precursor and adopting a thermal shock method.
Step S2, compounding Co@C pretreated by oxidized dodecyl dimethylamineThe material is dispersed in deionized water by ultrasonic to obtain the material with the concentration of 2-3 mg.ml -1 Co@c suspension of (c).
Step S3, dripping a certain volume of the Co@C suspension liquid into a solution with the concentration of 1-2 mg.ml -1 Ti of (2) 3 C 2 T x And (3) stirring in an MXene aqueous solution for 1-2 h in an ice bath to obtain a Co@C-MXene composite material suspension.
And S4, freeze-drying the Co@C-MXene composite material suspension in the step S2 to obtain the Co@C-MXene electromagnetic shielding material.
The electromagnetic shielding principle of the Co@C-MXene electromagnetic shielding material prepared by the application is that MXene reflects and scatters electromagnetic waves and Co@C absorbs the electromagnetic waves. The MXene can enhance the reflection and scattering of Co@C-MXene on electromagnetic waves and prevent the electromagnetic waves from penetrating through the material; the Co@C can absorb the reflected and scattered electromagnetic waves, so that the electromagnetic shielding performance of the Co@C-MXene composite material is further improved.
According to the application, co@C is soaked in a dodecyl dimethylamine solution with a certain concentration, and as C is a two-dimensional material with a larger specific surface area, the surface of Co@C is subjected to pretreatment of the dodecyl dimethylamine to adsorb the dodecyl dimethylamine oxide, so that the surface of Co@C is combined with oxygen-containing groups (such as O, OH). On the basis, the pretreated Co@C is dispersed in an MXene aqueous solution at a low temperature, and the surface of the MXene material is electronegative, so that the pretreated Co@C is easy to combine with the Co@C through electrostatic adsorption. In addition, the MXene material has larger specific surface area and surface vacancies, so that the MXene material has stronger surface adsorptivity, and the effective adsorption of Co@C on MXene can be realized.
In the step S1, a ZIF67 is used as a precursor to prepare the Co@C composite material by adopting a thermal shock method.
In some embodiments, the ZIF67 is prepared as follows:
0.1 to 0.3g of Co (NO) 3 ) 2 ·6H 2 O is fully dissolved in 30-50 ml of methanol to be used as solution A; fully dissolving 1-3 g of 2-methylimidazole in 30-50 ml of methanol to obtain a solution B; then, the solution B is added into the solution A rapidly, stirred for 24 hours at room temperature and then centrifugally dried to obtain the productZIF67。
The treatment process of the thermal shock method comprises the following steps:
and (3) taking a direct current power supply as an energy supply source, leading out two wires from the positive electrode and the negative electrode of the direct current power supply, respectively connecting the wires with two carbon cloths aligned vertically to form a loop, then placing the ZIF67 between the two carbon cloths, and performing thermal shock treatment on the ZIF67 in an inert gas atmosphere to obtain the Co@C composite material.
The thermal shock treatment is carried out according to the processes of 1-5 s of power-on, 2-5 s of power-off and 1-5 s of power-on; the output temperature of the thermal shock is 800-900 ℃.
The temperature of the thermal shock is not less than 800 ℃ and Co can be ensured 2+ Is completely reduced to simple substance Co. Meanwhile, the oxidation of the simple substance Co into CoO can be avoided under the inert gas atmosphere.
According to the application, the intermittent heating mode is innovatively adopted to perform thermal shock on the ZIF67 to prepare the Co@C, and compared with a thermal shock process of continuous heating, the intermittent heating can ensure a rapid heating-cooling process. In this process, co is maintained in the nanocrystalline state. If continuous heating is carried out without a cooling process, co nanocrystals can grow in clusters, and Co nanocrystals with the size of 50-80 nm cannot be obtained. Meanwhile, the intermittent heating mode is safer, and the continuous power-on work is easy to cause fire at high temperature.
Specifically, the energization time may be 1s, 2s, 3s, 4s, 5s. Preferably, the energizing time is 2 to 4s. Further preferably, the energization time is 3s.
Specifically, the output temperature of the thermal shock may be 800 ℃, 820 ℃, 840 ℃, 850 ℃, 860 ℃, 880 ℃, 900 ℃. Preferably, the output temperature of the thermal shock is 820-880 ℃. Further preferably, the output temperature of the thermal shock is 840 to 860 ℃.
In some embodiments, the inert gas is argon.
In step S2, the Co@C composite material pretreated by the oxidized dodecyl dimethylamine is dispersed in deionized water in an ultrasonic way to obtain the solution with the concentration of 2-3 mg.ml -1 Co@c suspension of (c).
According to the application, the Co@C composite material is pretreated by the dodecyl dimethylamine oxide, so that on one hand, the hanging chemical bond on the surface of the Co@C can be improved, the surface of Co@C particles is provided with positive electricity, and the Co@C can be combined with the MXene material forcefully and is not easy to fall off. On the other hand, co@C particles are prevented from agglomerating, so that the Co@C particles are kept in a nano state with high dispersity.
Specifically, the concentration of the Co@C composite material can be 2 mg.ml -1 、2.1mg·ml -1 、2.2mg·ml -1 、2.3mg·ml -1 、2.4mg·ml -1 、2.5mg·ml -1 、2.6mg·ml -1 、2.7mg·ml -1 、2.8mg·ml -1 、2.9mg·ml -1 、3.0mg·ml -1 . Preferably, the concentration of the Co@C composite material is 2.2-2.8mg.ml -1 . Further preferably, the concentration of the Co@C composite material is 2.4-2.6mg.ml -1 。
In some embodiments, the preprocessing is specifically as follows:
dispersing 20mg of the Co@C composite material in 30ml of a solution with the concentration of 8-20 mg.ml -1 Is soaked in the aqueous solution of the dodecyl dimethylamine oxide for 2 to 3 hours and is centrifugally treated for standby.
The shielding principle of Co@C for electromagnetic waves is absorption of incident electromagnetic waves. When the concentration of the dodecyl dimethylamine oxide is more than 20 mg.ml -1 When the Co@C particles are completely wrapped by the oxidized dodecyl dimethylamine, the conductivity of the Co@C is reduced, the absorption of the Co@C to electromagnetic waves is not facilitated, and the electromagnetic shielding capacity of the Co@C-MXene composite material is further reduced. Meanwhile, when the concentration of the dodecyldimethylamine oxide is less than 8 mg.ml -1 In this case, the Co@C surface dangling bonds are few and insufficient to be effectively bonded with MXene.
Specifically, the concentration of the dodecyldimethylamine oxide may be 8 mg.ml -1 、10mg·ml -1 、12mg·ml -1 、14mg·ml -1 、15mg·ml -1 、16mg·ml -1 、18mg·ml -1 、20mg·ml -1 . Preferably, the concentration of the dodecyl dimethylamine oxide is 12-16 mg.ml -1 . Further preferably, the concentration of the dodecyldimethylamine oxide is 14 to 15 mg.ml -1 。
Specifically, the soaking time can be 120min, 130min, 140min, 150min, 160min, 170min, 180min. Preferably, the soaking time is 130-170 min. Further preferably, the soaking time is 140 to 160 minutes.
In step S3, a certain volume of the Co@C suspension is dripped into the solution with the concentration of 1-2 mg.ml -1 Ti of (2) 3 C 2 T x And (3) stirring in an MXene aqueous solution for 1-2 h in an ice bath to obtain a Co@C-MXene composite material suspension.
Decomposition and oxidation of MXene can be avoided by stirring with an ice bath.
Specifically, the Ti is 3 C 2 T x The concentration of MXene may be 1 mg.ml -1 、1.1mg·ml -1 、1.2mg·ml -1 、1.3mg·ml -1 、1.4mg·ml -1 、1.5mg·ml -1 、1.6mg·ml -1 、1.7mg·ml -1 、1.8mg·ml -1 、1.9mg·ml -1 、2.0mg·ml -1 . Preferably, the Ti is 3 C 2 T x The concentration of MXene is 1.2-1.8 mg.ml -1 . Further preferably, the Ti 3 C 2 T x The concentration of MXene is 1.4-1.6mg.ml -1 。
Specifically, the ice bath stirring time can be 60min, 70min, 80min, 90min, 95min, 100min, 110min, 120min. Preferably, the stirring time of the ice bath is 80-110 min. Further preferably, the ice bath stirring time is 90-100 min.
In some embodiments, the volume of the Co@C suspension is from 5 to 10ml.
In particular, the volume of the Co@C suspension may be 5ml, 6ml, 7ml, 8ml, 9ml, 10ml. Preferably, the volume of the Co@C suspension is 7-8.ml.
In some embodiments, the Ti is 3 C 2 T x The volume of the MXene aqueous solution is 50-55 ml.
And S4, freeze-drying the Co@C-MXene composite material suspension in the step S3 to obtain the Co@C-MXene electromagnetic shielding material.
Compared with other drying means, the freeze drying can better retain the two-dimensional structure of the whole Co@C-MXene composite material. Meanwhile, the Co@C-MXene composite material can be prevented from being oxidized due to exposure under the condition of little water and air.
In some embodiments, the step S4 includes:
and S41, freezing the Co@C-MXene composite material suspension by utilizing liquid nitrogen to obtain a solid Co@C-MXene composite material.
And S42, freeze-drying the solid Co@C-MXene composite material in the step S41 for 20-24 hours by using a freeze dryer, and sublimating liquid molecules to obtain the Co@C-MXene electromagnetic shielding material.
Wherein the temperature of the freeze drying is lower than-70 ℃ and the pressure is less than 0.001Pa.
Specifically, the time of freeze-drying may be 20h, 21h, 22h, 23h, 24h. Preferably, the freeze-drying time is 22 hours.
The second aspect of the application discloses a spindle-shaped Co@C-MXene electromagnetic shielding material. The electromagnetic shielding performance of the spindle-shaped Co@C-MXene electromagnetic shielding material in the 5-8.5GHz microwave frequency band is higher than 40dB.
Example 1
Preparation of Co@C-MXene electromagnetic shielding material
(1) 0.2g of Co (NO 3 ) 2 .6H 2 O was sufficiently dissolved in 40ml of methanol as solution A; 2g of 2-methylimidazole was sufficiently dissolved in 40ml of methanol as a solution B; then, the solution B was added to the solution A rapidly, stirred at room temperature for 24 hours, and dried by centrifugation to obtain ZIF67.
(2) Two leads are led out from the positive electrode and the negative electrode of the direct current power supply by using the direct current power supply as an energy supply, and are respectively connected with two carbon cloths aligned up and down to form a loop, and then ZIF67 is arranged between the two carbon cloths, and thermal shock treatment is carried out on the ZIF67 under the argon atmosphere to obtain a Co@C composite material;
wherein, the thermal shock treatment is carried out according to the processes of 3s of electrifying, 3s of de-electrifying and 3s of electrifying; the output temperature of the thermal shock was 850 ℃.
(3) Ultrasonic dispersing 20mg Co@C composite material in 30ml of a solution with the concentration of 14 mg.ml -1 Is soaked in the aqueous solution of the dodecyl dimethylamine oxide for 2.5 hours and is centrifugally treated for standby. Ultrasonically dispersing the Co@C composite material pretreated by the oxidized dodecyl dimethylamine in deionized water to obtain the composite material with the concentration of 2.5 mg.ml -1 Co@c suspension of (c). Dropping 8ml of Co@C suspension into 50ml of the solution with the concentration of 1-2 mg.ml -1 Ti of (2) 3 C 2 T x And (3) stirring the mixture in an MXene aqueous solution for 1.5h in an ice bath to obtain a Co@C-MXene composite material suspension.
(4) And (3) freezing the Co@C-MXene composite material suspension obtained in the step by utilizing liquid nitrogen to obtain a solid Co@C-MXene composite material. And then, freeze-drying the solid Co@C-MXene composite material for 22 hours by using a freeze dryer to obtain the Co@C-MXene electromagnetic shielding material.
Wherein the temperature of the freeze drying is lower than-70 ℃ and the pressure is less than 0.001Pa.
FIG. 2 (a) is a transmission electron micrograph of ZIF-67, showing that ZIF-67 has a regular polyhedral shape before thermal shock. Fig. 2 (b) is a transmission electron micrograph of co@c, and it can be seen that co@c particles formed by thermal decomposition of ZIF67 are spindle-shaped with two tips, and Co nanocrystals are embedded in the C film, with the Co nanocrystal particles being about 50-80 nm. FIG. 2 (c) is a transmission electron micrograph of the Co@C-MXene electromagnetic shielding material prepared in the specific example 1 according to the present application. As can be seen from fig. 2 (c), the spindle-shaped co@c and the MXene substrate are well combined, and after the freeze drying treatment, the two ends of the co@c particles are sharper, the spindle shape is more obvious, which is helpful for exciting electrons with higher density to the incident electromagnetic wave, so that the co@c-MXene electromagnetic shielding material has stronger shielding effect to the electromagnetic wave.
FIG. 3 is an X-ray photoelectron spectrum of a Co@C-MXene electromagnetic shielding material according to embodiment 1 of the present application. Fig. 3 further demonstrates the presence of element Co, C, ti, O, F. Wherein Co element is derived from Co@C, ti, O and F are derived from MXene, and C is derived from Co@C and MXene.
FIG. 4 shows the results of electromagnetic shielding performance tests at the microwave frequency range of 5.5-8.5GHz for Co@C, MXene and Co@C-MXene electromagnetic shielding materials according to specific embodiment 1 of the application. As can be seen from FIG. 4, the electromagnetic shielding effectiveness of Co/C@MXene at 5.5-8GHz is significantly improved, up to 120dB, compared to single Co/C nanocrystalline particles and MXene films.
Example 2
Preparation of Co@C-MXene electromagnetic shielding material
(1) 0.3g of Co (NO 3 ) 2 .6H 2 O was sufficiently dissolved in 50ml of methanol as solution A; 3g of 2-methylimidazole was sufficiently dissolved in 50ml of methanol as a solution B; then, the solution B was added to the solution A rapidly, stirred at room temperature for 24 hours, and dried by centrifugation to obtain ZIF67.
(2) Two leads are led out from the positive electrode and the negative electrode of the direct current power supply by using the direct current power supply as an energy supply, and are respectively connected with two carbon cloths aligned up and down to form a loop, and then ZIF67 is arranged between the two carbon cloths, and thermal shock treatment is carried out on the ZIF67 under the argon atmosphere to obtain a Co@C composite material;
wherein, the thermal shock treatment is carried out according to the processes of 5s of power-on, 4s of power-off and 5s of power-on; the output temperature of the thermal shock was 800 ℃.
(3) Ultrasonic dispersing 20mg Co@C composite material in 30ml of 20 mg.ml concentration -1 Is soaked in the aqueous solution of the dodecyl dimethylamine oxide for 2 hours and is centrifugally treated for standby. Ultrasonically dispersing the Co@C composite material pretreated by the oxidized dodecyl dimethylamine in deionized water to obtain the composite material with the concentration of 3 mg.ml -1 Co@c suspension of (c). 10ml of Co@C suspension was dropped into 50ml of a concentration of 2 mg.ml -1 Ti of (2) 3 C 2 T x And (3) stirring the mixture in an MXene aqueous solution for 2 hours in an ice bath to obtain a Co@C-MXene composite material suspension.
(4) And (3) freezing the Co@C-MXene composite material suspension obtained in the step by utilizing liquid nitrogen to obtain a solid Co@C-MXene composite material. And then, freeze-drying the solid Co@C-MXene composite material for 24 hours by using a freeze dryer to obtain the Co@C-MXene electromagnetic shielding material.
Wherein the temperature of the freeze drying is lower than-70 ℃ and the pressure is less than 0.001Pa.
Example 3
Preparation of Co@C-MXene electromagnetic shielding material
(1) 0.1g of Co (NO 3 ) 2 .6H 2 O was sufficiently dissolved in 30ml of methanol as solution A; 1g of 2-methylimidazole was sufficiently dissolved in 30ml of methanol as a solution B; then, the solution B was added to the solution A rapidly, stirred at room temperature for 24 hours, and dried by centrifugation to obtain ZIF67.
(2) Two leads are led out from the positive electrode and the negative electrode of the direct current power supply by using the direct current power supply as an energy supply, and are respectively connected with two carbon cloths aligned up and down to form a loop, and then ZIF67 is arranged between the two carbon cloths, and thermal shock treatment is carried out on the ZIF67 under the argon atmosphere to obtain a Co@C composite material;
wherein, the thermal shock treatment is carried out according to the processes of 2s for electrifying, 2s for de-electrifying and 2s for electrifying; the output temperature of the thermal shock was 880 ℃.
(3) Ultrasonic dispersing 20mg Co@C composite material in 30ml of a solution with the concentration of 8 mg.ml -1 Is soaked in the aqueous solution of the dodecyl dimethylamine oxide for 3 hours and is centrifugally treated for standby. Ultrasonically dispersing the Co@C composite material pretreated by the oxidized dodecyl dimethylamine in deionized water to obtain the composite material with the concentration of 2 mg.ml -1 Co@c suspension of (c). 10ml of Co@C suspension was dropped into 55ml of a concentration of 1 mg.ml -1 Ti of (2) 3 C 2 T x And (3) stirring the mixture in an MXene aqueous solution for 1h in an ice bath to obtain a Co@C-MXene composite material suspension.
(4) And (3) freezing the Co@C-MXene composite material suspension obtained in the step by utilizing liquid nitrogen to obtain a solid Co@C-MXene composite material. And then, freeze-drying the solid Co@C-MXene composite material for 20 hours by using a freeze dryer to obtain the Co@C-MXene electromagnetic shielding material.
Wherein the temperature of the freeze drying is lower than-70 ℃ and the pressure is less than 0.001Pa.
Example 4
Preparation of Co@C-MXene electromagnetic shielding material
(1) 0.15g of Co (NO 3 ) 2 .6H 2 O was sufficiently dissolved in 35ml of methanol as solution A; 1.5g of 2-methylimidazole was sufficiently dissolved in 35ml of methanol as a solution B; then, the solution B was added to the solution A rapidly, stirred at room temperature for 24 hours, and dried by centrifugation to obtain ZIF67.
(2) Two leads are led out from the positive electrode and the negative electrode of the direct current power supply by using the direct current power supply as an energy supply, and are respectively connected with two carbon cloths aligned up and down to form a loop, and then ZIF67 is arranged between the two carbon cloths, and thermal shock treatment is carried out on the ZIF67 under the argon atmosphere to obtain a Co@C composite material;
wherein, the thermal shock treatment is carried out according to the processes of 1s of power-on, 2s of power-off and 1s of power-on; the output temperature of the thermal shock was 900 ℃.
(3) 20mg of Co@C composite material is ultrasonically dispersed in 30ml of a solution with the concentration of 12 mg.ml -1 Is soaked in the aqueous solution of the dodecyl dimethylamine oxide for 130min and is centrifugally treated for standby. Ultrasonically dispersing the Co@C composite material pretreated by the oxidized dodecyl dimethylamine in deionized water to obtain the solution with the concentration of 2.2 mg.ml -1 Co@c suspension of (c). 7ml of Co@C suspension was dropped into 50ml of a concentration of 1.2 mg.ml -1 Ti of (2) 3 C 2 T x And (3) in the MXene aqueous solution, stirring for 80min in an ice bath to obtain Co@C-MXene composite material suspension.
(4) And (3) freezing the Co@C-MXene composite material suspension obtained in the step by utilizing liquid nitrogen to obtain a solid Co@C-MXene composite material. And then, freeze-drying the solid Co@C-MXene composite material for 21 hours by using a freeze dryer to obtain the Co@C-MXene electromagnetic shielding material.
Wherein the temperature of the freeze drying is lower than-70 ℃ and the pressure is less than 0.001Pa.
Example 5
Preparation of Co@C-MXene electromagnetic shielding material
(1) 0.25g of Co (NO 3 ) 2 .6H 2 O was sufficiently dissolved in 45ml of methanol as solution A; 2.5g of 2-methylimidazole was sufficiently dissolved in 45mlMethanol as solution B; then, the solution B was added to the solution A rapidly, stirred at room temperature for 24 hours, and dried by centrifugation to obtain ZIF67.
(2) Two leads are led out from the positive electrode and the negative electrode of the direct current power supply by using the direct current power supply as an energy supply, and are respectively connected with two carbon cloths aligned up and down to form a loop, and then ZIF67 is arranged between the two carbon cloths, and thermal shock treatment is carried out on the ZIF67 under the argon atmosphere to obtain a Co@C composite material;
wherein, the thermal shock treatment is carried out according to the processes of 4s of power on, 5s of power off and 4s of power on; the output temperature of the thermal shock was 820 ℃.
(3) 20mg of Co@C composite material is ultrasonically dispersed in 30ml of a solution with the concentration of 16 mg.ml -1 Is soaked in the aqueous solution of the dodecyl dimethylamine oxide for 160min, and is centrifugally treated for standby. Ultrasonically dispersing the Co@C composite material pretreated by the oxidized dodecyl dimethylamine in deionized water to obtain the solution with the concentration of 2.8 mg.ml -1 Co@c suspension of (c). 6ml of Co@C suspension was dropped into 53ml of a concentration of 1.8 mg.multidot.ml -1 Ti of (2) 3 C 2 T x And (3) stirring the mixture in an MXene aqueous solution in an ice bath for 110min to obtain a Co@C-MXene composite material suspension.
(4) And (3) freezing the Co@C-MXene composite material suspension obtained in the step by utilizing liquid nitrogen to obtain a solid Co@C-MXene composite material. And then, freeze-drying the solid Co@C-MXene composite material for 23 hours by using a freeze dryer to obtain the Co@C-MXene electromagnetic shielding material.
Wherein the temperature of the freeze drying is lower than-70 ℃ and the pressure is less than 0.001Pa.
In summary, the scheme provided by the application has the following technical effects:
the application creatively introduces the magnetic material and the dielectric material Co@C into the MXene two-dimensional material, thereby effectively improving the electromagnetic shielding performance of the composite material. According to the application, co@C is soaked in a dodecyl dimethylamine solution with a certain concentration, and the surface of Co@C is adsorbed by the pretreated surface of Co@C which is a two-dimensional material with a larger specific surface area, so that the surface of Co@C has positive electricity. On the basis, the pretreated Co@C is dispersed in an MXene aqueous solution at a low temperature, and the surface of the MXene material is electronegative, so that the pretreated Co@C is easy to combine with the Co@C through electrostatic adsorption. In addition, the MXene material has larger specific surface area and surface vacancies, so that the MXene material has stronger surface adsorptivity, and the effective adsorption of Co@C on MXene can be realized.
In addition, after the Co@C-MXene composite material suspension is subjected to freeze drying treatment, the two ends of Co@C particles are sharper, the spindle shape is more obvious, and electrons with higher density can be excited to incident electromagnetic waves, so that the Co@C-MXene electromagnetic shielding material has stronger shielding effect on the electromagnetic waves. The Co@C-MXene electromagnetic shielding material prepared by the method has the electromagnetic shielding performance higher than 40dB and up to 120dB in the 5-8.5GHz microwave frequency band, and has the characteristics of light weight and good stability.
In addition, the Co@C-MXene electromagnetic shielding material prepared by the freeze-drying method is reliable in repeatability, can realize batch production of the material, and is suitable for industrial production.
Note that the technical features of the above embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be regarded as the scope of the description. The foregoing examples illustrate only a few embodiments of the application, which are described in detail and are not to be construed as limiting the scope of the application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of protection of the present application is to be determined by the appended claims.
Claims (7)
1. A method for preparing a spindle-shaped co@c-MXene electromagnetic shielding material, comprising the steps of:
step S1, preparing a Co@C composite material by taking ZIF67 as a precursor and adopting a thermal shock method;
s2, ultrasonically dispersing the Co@C composite material pretreated by the oxidized dodecyl dimethylamine in deionized water to obtain the solution with the concentration of 2-3 mg . ml -1 Co@c suspension of (c);
step S3, dripping the Co@C suspension liquid with the volume of 5-10 ml into the solution with the concentration of 1-2 mg . ml -1 Ti of (2) 3 C 2 T x Stirring in an MXene aqueous solution for 1-2 h in an ice bath to obtain Co@C-MXene composite material suspension;
step S4, freeze-drying the Co@C-MXene composite material suspension in the step S3 to obtain a Co@C-MXene electromagnetic shielding material;
the preparation process of the ZIF67 comprises the following steps:
0.1 to 0.3g of Co (NO) 3 ) 2. 6H 2 O is fully dissolved in 30-50 ml of methanol to be used as solution A; fully dissolving 1-3 g of 2-methylimidazole in 30-50 ml of methanol to obtain a solution B; then, the solution B is added into the solution A rapidly, stirred for 24 hours at room temperature and then centrifugally dried to obtain the ZIF67.
2. The method for preparing a spindle-shaped co@c-MXene electromagnetic shielding material according to claim 1, characterized in that in the step S1, the thermal shock method is specifically performed as follows:
two leads are led out from the positive electrode and the negative electrode of the direct current power supply by using the direct current power supply as an energy supply power supply and are respectively connected with two carbon cloths aligned up and down to form a loop, then the ZIF67 is arranged between the two carbon cloths, and thermal shock treatment is carried out on the ZIF67 under the inert gas atmosphere to obtain a Co@C composite material;
the thermal shock treatment is carried out according to the processes of 1-5 s of power-on, 2-5 s of power-off and 1-5 s of power-on; the output temperature of the thermal shock is 800-900 ℃.
3. The method for preparing a spindle-shaped co@c-MXene electromagnetic shielding material according to claim 1, characterized in that in said step S2, the pretreatment process is specifically as follows:
dispersing 20mg of the Co@C composite material in 30ml of a solution with the concentration of 8-20mg . ml -1 Is soaked in the aqueous solution of the dodecyl dimethylamine oxide for 2 to 3 hours and is centrifugally treated for standby.
4. The method for producing a spindle-shaped Co@C-MXene electromagnetic shielding material according to claim 1, wherein in said step S3, said Ti 3 C 2 T x The volume of the MXene aqueous solution is 50-55 ml.
5. The method for preparing a spindle-shaped co@c-MXene electromagnetic shielding material according to claim 1, characterized in that the step S4 comprises:
s41, freezing the Co@C-MXene composite material suspension by utilizing liquid nitrogen to obtain a solid Co@C-MXene composite material;
step S42, freeze-drying the solid Co@C-MXene composite material in the step S41 for 20-24 hours by using a freeze dryer, and sublimating liquid molecules to obtain a Co@C-MXene electromagnetic shielding material;
wherein the temperature of the freeze drying is lower than-70 ℃ and the pressure is less than 0.001Pa.
6. The method for producing a spindle-shaped co@c-MXene electromagnetic shielding material according to claim 2, characterized in that the inert gas is argon.
7. A spindle-shaped co@c-MXene electromagnetic shielding material prepared by the method for preparing a spindle-shaped co@c-MXene electromagnetic shielding material according to any one of claims 1 to 6, characterized in that the electromagnetic shielding performance of the spindle-shaped co@c-MXene electromagnetic shielding material in a microwave frequency band of 5 to 8.5GHz is higher than 40dB.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211422614.XA CN115942728B (en) | 2022-11-15 | 2022-11-15 | Spindle-shaped Co@C-Mxene electromagnetic shielding material and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211422614.XA CN115942728B (en) | 2022-11-15 | 2022-11-15 | Spindle-shaped Co@C-Mxene electromagnetic shielding material and preparation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115942728A CN115942728A (en) | 2023-04-07 |
| CN115942728B true CN115942728B (en) | 2023-08-29 |
Family
ID=86699928
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211422614.XA Active CN115942728B (en) | 2022-11-15 | 2022-11-15 | Spindle-shaped Co@C-Mxene electromagnetic shielding material and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115942728B (en) |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106565964A (en) * | 2016-11-04 | 2017-04-19 | 石家庄学院 | Preparation method of metal polyphenol vesicle material with micrometer/nanometer multilayer composite structure |
| CN108975462A (en) * | 2018-08-23 | 2018-12-11 | 中南大学 | A kind of ferrite modification MXene laminar gas diffusion electrode and the preparation method and application thereof |
| KR102085753B1 (en) * | 2018-11-23 | 2020-03-06 | 원광대학교 산학협력단 | Carbon fiber composite comprising unwoven carbon fabric coated with MAXene and oxidized carbon nanotube, method for manufacturing the same and use thereof |
| CN111757657A (en) * | 2019-03-27 | 2020-10-09 | 天津大学 | Two-dimensional graphene-coated copper composite material with core-shell structure and preparation method and application thereof |
| CN114039051A (en) * | 2021-11-01 | 2022-02-11 | 新纶新能源材料(常州)有限公司 | MXene/SnO with three-dimensional structure2/C negative electrode composite material and preparation method thereof |
| WO2022032743A1 (en) * | 2020-08-12 | 2022-02-17 | 五邑大学 | Cote2/mxene composite material and preparation method therefor |
| CN114405526A (en) * | 2021-12-29 | 2022-04-29 | 天津工业大学 | Preparation and application of two-dimensional MXene nanosheet modified porous Au @ Ag @ Pd core-shell structure photocatalyst |
| CN114561805A (en) * | 2022-01-25 | 2022-05-31 | 中国人民解放军国防科技大学 | Flexible electromagnetic shielding material and preparation method thereof |
| CN114614272A (en) * | 2022-03-08 | 2022-06-10 | 福建工程学院 | MXene/Co/C composite wave-absorbing material derived from MOF and preparation method thereof |
| CN115000366A (en) * | 2022-05-19 | 2022-09-02 | 同济大学 | Flexible self-supporting lithium-sulfur battery positive electrode film with core-shell structure and preparation method |
-
2022
- 2022-11-15 CN CN202211422614.XA patent/CN115942728B/en active Active
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106565964A (en) * | 2016-11-04 | 2017-04-19 | 石家庄学院 | Preparation method of metal polyphenol vesicle material with micrometer/nanometer multilayer composite structure |
| CN108975462A (en) * | 2018-08-23 | 2018-12-11 | 中南大学 | A kind of ferrite modification MXene laminar gas diffusion electrode and the preparation method and application thereof |
| KR102085753B1 (en) * | 2018-11-23 | 2020-03-06 | 원광대학교 산학협력단 | Carbon fiber composite comprising unwoven carbon fabric coated with MAXene and oxidized carbon nanotube, method for manufacturing the same and use thereof |
| CN111757657A (en) * | 2019-03-27 | 2020-10-09 | 天津大学 | Two-dimensional graphene-coated copper composite material with core-shell structure and preparation method and application thereof |
| WO2022032743A1 (en) * | 2020-08-12 | 2022-02-17 | 五邑大学 | Cote2/mxene composite material and preparation method therefor |
| CN114039051A (en) * | 2021-11-01 | 2022-02-11 | 新纶新能源材料(常州)有限公司 | MXene/SnO with three-dimensional structure2/C negative electrode composite material and preparation method thereof |
| CN114405526A (en) * | 2021-12-29 | 2022-04-29 | 天津工业大学 | Preparation and application of two-dimensional MXene nanosheet modified porous Au @ Ag @ Pd core-shell structure photocatalyst |
| CN114561805A (en) * | 2022-01-25 | 2022-05-31 | 中国人民解放军国防科技大学 | Flexible electromagnetic shielding material and preparation method thereof |
| CN114614272A (en) * | 2022-03-08 | 2022-06-10 | 福建工程学院 | MXene/Co/C composite wave-absorbing material derived from MOF and preparation method thereof |
| CN115000366A (en) * | 2022-05-19 | 2022-09-02 | 同济大学 | Flexible self-supporting lithium-sulfur battery positive electrode film with core-shell structure and preparation method |
Non-Patent Citations (1)
| Title |
|---|
| 陶瓷表面化学镀Ni-P合金工艺的研究;李丽波;李东平;张书华;赵春山;李佳;杨照地;李晓霞;谢菁琛;国绍文;;电镀与环保(第03期);全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN115942728A (en) | 2023-04-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Vaez et al. | Synthesis, characterization and photocatalytic activity of ZSM-5/ZnO nanocomposite modified by Ag nanoparticles for methyl orange degradation | |
| Wei et al. | Composite ZIF-8 with CQDs for boosting visible-light-driven photocatalytic removal of NO | |
| Zhang et al. | Photocatalytic degradation of rhodamine B by using a nanocomposite of cuprous oxide, three-dimensional reduced graphene oxide, and nanochitosan prepared via one-pot synthesis | |
| CN113877575B (en) | Novel perovskite composite photocatalyst and application thereof | |
| CN112521617B (en) | Polyacid-based metal organic framework material for adsorbing antibiotics and preparation method and application thereof | |
| CN102350335A (en) | Method for preparing nanometer titanium dioxide/graphene composite hydrogel at room temperature | |
| Liu et al. | Synthesis of a novel magnetic SnNb2O6/CoFe-LDH 2D/2D heterostructure for the degradation of organic pollutants under visible light irradiation | |
| CN109503858B (en) | Magnetic sandwich structure metal organic framework material and preparation method thereof | |
| CN106986316A (en) | A kind of vanadium nitride material and its preparation method and application | |
| CN113181949B (en) | Co-Fe alloy/N-S co-doped carbon nano composite material and preparation method and application thereof | |
| CN112973753B (en) | Preparation method and application of Z-type heterojunction aerogel type photocatalytic material | |
| Chen et al. | Self-assembling TiO2 on aminated graphene based on adsorption and catalysis to treat organic dyes | |
| Navgire et al. | β-Cyclodextrin supported MoO 3–CeO 2 nanocomposite material as an efficient heterogeneous catalyst for degradation of phenol | |
| Qu et al. | Novel pn type polyimide aerogels/BiOBr heterojunction for visible light activated high efficient photocatalytic degradation of organic contaminants | |
| CN113262808A (en) | Water-soluble graphite-phase carbon nitride nanosheet catalyst for efficiently removing formaldehyde at room temperature and preparation method thereof | |
| Wu et al. | A low-cost cementite (Fe 3 C) nanocrystal@ N-doped graphitic carbon electrocatalyst for efficient oxygen reduction | |
| Wang et al. | Synergistic enhancement of the visible-light photocatalytic activity of hierarchical 3D BiOClxBr1-x/graphene oxide heterojunctions for formaldehyde degradation at room temperature | |
| Zhu et al. | Ternary Fe 3 O 4@ PANI@ Au nanocomposites as a magnetic catalyst for degradation of organic dyes | |
| CN114522709B (en) | Three-dimensional porous graphite phase carbon nitride/bismuth oxyiodide/silver nanoparticle composite photocatalyst and preparation method and application thereof | |
| CN115942728B (en) | Spindle-shaped Co@C-Mxene electromagnetic shielding material and preparation method thereof | |
| Grishchenko et al. | Electromagnetic interference shielding of carbon fibers oxidatively brominated in the liquid-phase | |
| CN112642461B (en) | Modified cuprous ferrite catalyst rich in oxygen vacancies and preparation method and application thereof | |
| CN112871209A (en) | High-efficiency photocatalytic hydrogen production catalytic system and preparation method thereof | |
| Martynov et al. | New hybrid materials based on nanostructured aluminum oxyhydroxide and terbium (III) bis (tetra-15-crown-5-phthalocyaninate) | |
| CN112642459A (en) | Advanced oxidation catalyst and preparation method and application thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |