CN115650286A - rGO/MXene/TiO 2 /Fe 2 Preparation method of C multi-stage heterostructure porous microsphere wave-absorbing material - Google Patents
rGO/MXene/TiO 2 /Fe 2 Preparation method of C multi-stage heterostructure porous microsphere wave-absorbing material Download PDFInfo
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Abstract
The invention relates to rGO/MXene/TiO 2 /Fe 2 A preparation method of a C multi-stage heterostructure porous microsphere wave-absorbing material. The method takes MXene, graphene Oxide (GO) and water dispersion as mother solution, adopts a spray-freeze drying technology to induce self-assembly of a two-dimensional material to obtain GO/MXene porous microspheres, and then combines the GO/MXene porous microspheres and the MXene porous microspheresThe microwave irradiation method promotes the oxidation-reduction reaction between GO and MXene, and simultaneously initiates the decomposition of ferrocene on the surface of the porous microsphere skeleton to form Fe 2 C nano particles to finally obtain rGO/MXene/TiO 2 /Fe 2 C, multi-stage heterostructure porous microspheres. Wherein the zero-dimensional (0D) TiO 2 And magnetic Fe 2 The C nano-particles are loaded on the surface of a porous skeleton formed by two-dimensional (2D) reduced graphene oxide (rGO) and MXene, and finally the porous microsphere containing a large amount of 2D/0D multilevel heterostructure is formed. The structure enhances interface polarization and multiple scattering, and is beneficial to improving the electromagnetic wave absorption capacity. The multi-level heterostructure porous microsphere prepared by the method has good electromagnetic wave absorption performance and has wide application potential in the fields of electromagnetic stealth, safety protection and the like.
Description
Technical Field
The invention relates to rGO/MXene/TiO 2 /Fe 2 A preparation method of a C-stage heterostructure porous microsphere wave-absorbing material belongs to the field of functional materials.
Background
With the popularization of digital equipment and the development of radar detection technology, microwave absorbing materials play more and more important roles in the aspects of electronic reliability, medical care and national defense safety, and development of high-performance wave absorbing materials with thin thickness, low density, wide bandwidth and strong absorption also becomes a research focus.
Two-dimensional materials such as graphene and MXene have excellent electrical conductivity, thermal conductivity and high specific surface area and are widely applied to the field of wave-absorbing materials. However, graphene and MXene alone have relatively limited absorption of electromagnetic waves due to the single loss mechanism of graphene and impedance mismatch due to the higher conductivity of MXene.
In addition, the two-dimensional material is assembled into three-dimensional structures such as aerogel, the reflection and scattering paths of microwave can be prolonged, a new interface is generated, impedance matching is adjusted, and the microwave absorption effect is improved. Therefore, the graphene and MXene are combined to be assembled into a three-dimensional structure, the defect of electromagnetic energy attenuation of a single material is overcome, the impedance matching of the single material and the MXene is improved, and the method is a way for developing novel wave-absorbing materials.
Considering the synergistic effect of dielectric loss and magnetic loss in electromagnetic absorption, introducing magnetic nanoparticles is an effective method for improving the wave absorption performance of materials, and CN 110283570A discloses a method for preparing a FeCo/MXene composite wave-absorbing material by a solvothermal method, however, a reaction kettle needs to be heated to a high temperature and kept for a long reaction time, and the reaction conditions are complex; CN 113371765A discloses a preparation method of an electromagnetic wave-absorbing material based on a NiFe layered double-metal oxide modified MXene, however, the reaction period is long, roasting is required under the protection of inert gas, and the reaction conditions are not easy to control. Optimizing electromagnetic compounding through rational structural and compositional regulation remains a challenge.
Disclosure of Invention
The invention aims to provide a rGO/MXene/TiO preparation aiming at the defects of the prior art 2 /Fe 2 A preparation method of a C multi-stage heterostructure porous microsphere wave-absorbing material. After spray freeze drying, the invention quickly synthesizes the rGO/MXene/TiO with excellent performance in a microwave-assisted and high-efficiency manner 2 /Fe 2 C, a multi-stage heterostructure porous microsphere wave-absorbing material. Compared with CN113213455A, the method is improved from a two-dimensional stacking structure on the basis of CN113213455A, magnetic particles are loaded on a three-dimensional porous framework, and high porosity is more advantageous in the aspect of constructing a continuous conductive network.
The technical scheme adopted by the invention is as follows:
the invention firstly provides rGO/MXene/TiO 2 /Fe 2 The preparation method of the C-stage heterostructure porous microsphere wave-absorbing material comprises the following steps:
(1) Preparation of the dispersion: mixing Graphene Oxide (GO) and few-layer Ti 3 C 2 T x Dispersing the MXene suspension into deionized water, and uniformly stirring to obtain a water dispersion of the two-dimensional material;
(2) Preparing GO/MXene porous microspheres: loading the dispersion liquid into an atomizer, atomizing the dispersion liquid into a container filled with liquid nitrogen, collecting frozen droplets, and performing freeze drying treatment to obtain GO/MXene porous microspheres;
(3)rGO/MXene/TiO 2 /Fe 2 c, preparation of the porous microsphere with the multilevel heterostructure: grinding and mixing the porous microspheres and metallocene; adding carbon fiber into the mixture, and reacting in a microwave reactor at a fixed power in an argon atmosphere to finally obtain rGO/MXene/TiO 2 /Fe 2 C, multi-stage heterostructure porous microspheres.
In a preferred embodiment of the present invention, in the step (1), the graphene oxide is synthesized by a Brodie method, a Staudenmaier method, or a Hummers method.
As a preferable embodiment of the present invention, in the step (1), the small-layer Ti 3 C 2 T x MXene suspension adopts LiF-HCl system to etch Ti 3 C 2 T x MAX phase method preparation, including the following steps: adding LiF into a hydrochloric acid solution with the concentration of 9-10 mol/L to ensure that the concentration of LiF is 60-100 mg/mL, and uniformly stirring; adding Ti 3 C 2 T x And enabling the mass ratio of MAX phase to LiF to be 1: (2-4); reacting for 40-48h at the temperature of 40-50 ℃ and the stirring speed of 300-600 rpm; centrifugally washing the product after the reaction at 3000-4000 rpm for 1-2 min, and circularly operating until the pH value of the supernatant is more than or equal to 6; collecting the precipitate, ultrasonically stripping in ice-water bath under inert atmosphere for 40-60 min, centrifuging the ultrasonic product at 3000-4000 rpm for 20-35min, and collecting the supernatant to obtain Ti 3 C 2 T x MXene suspension.
As a preferred embodiment of the present invention, said MAX phase comprises Ti 3 AlC 2 、Ti 3 SiC 2 、Ti 2 AlC、Ti 2 SnC、 Ti 2 SC、Ti 2 AlN、V 2 AlC、Ti 3 AlCN、Nb 2 AlC、Nb 2 SnC、Ta 2 Any one or the combination of more than two of AlC, and the corresponding MXene two-dimensional material comprises Ti 3 C 2 T x 、Ti 2 CT x 、Ti 2 NT x 、V 2 CT x 、Ti 3 CNT x 、 Nb 2 CT x 、Ta 2 CT x Any one or a combination of two or more of them.
As a preferable scheme of the invention, in the step (1), the total concentration of the aqueous dispersion of the two-dimensional material is 2-6 mg/mL, GO and few Ti layers 3 C 2 T x The solute mass ratio of MXene is 1: (0.3 to 3); the stirring speed is 300-600rpm, and the stirring time is 1-3h.
In the preferred embodiment of the present invention, in the step (2), the operation power of the air pump of the atomizer is 8W to 25W, and the flow rate of the atomized liquid ejected from the dispersion is 10mL/min to 30mL/min.
As a preferable scheme of the invention, in the mixture in the step (3), the mass ratio of the microspheres is 40-50%, and the mass ratio of the metallocene is 50-60%; the type of the carbon fiber is any one of T300, T700 and T800, and the adding amount of the carbon fiber is 13-16% of the mass of the mixture.
As a preferable scheme of the invention, in the step (3), the fixed power of the microwave reaction is 700-1000W, and the reaction time is 70-120 s; the metallocene is ferrocene or a derivative thereof; the ferrocene derivatives are one or more of ferrocene formaldehyde, 1,1 '-diene bis (pinacol) borate, 1,1' -bis (diphenylphosphino) ferrocene, and nickel metallocene, cobalt metallocene and derivatives thereof.
In a preferred embodiment of the present invention, the grinding and mixing in step (3) is performed by using a planetary centrifugal mixer at a rotation speed of 800 to 1200r/min for a mixing time of 100 to 200s.
The invention also discloses the rGO/MXene/TiO prepared by the method 2 /Fe 2 C, multi-stage heterostructure porous microspheres. It is prepared from rGO, MXene and TiO 2 And magnetic Fe 2 C nano particles, wherein magnetic metal nano particles are loaded on the surfaces of rGO and MXene. The rGO/MXene/TiO prepared by the invention 2 /Fe 2 The minimum reflection loss value of the C multilevel heterostructure porous microsphere can reach-67.4 dB in the frequency range of 2-18 GHz.
Compared with the prior art, the invention has the beneficial effects that:
1) According to the invention, the porous microspheres are prepared by adopting a spray-freeze drying method, and the GO and MXene two-dimensional materials are subjected to the extrusion action of frozen ice crystals, so that the induced assembly is carried out to form a large-surface-area porous two-dimensional material skeleton structure, a conductive network and multiple scattering loss are favorably formed, and the loss of electromagnetic wave energy is promoted.
2) After spray freeze drying, the invention quickly synthesizes the rGO/MXene/TiO with excellent performance in a microwave-assisted and high-efficiency manner 2 /Fe 2 C, a multi-stage heterostructure porous microsphere wave-absorbing material; the microwave radiation realizes the redox reaction between the graphene oxide and MXene and Fe 2 The C nano particle growth synergistic effect effectively inhibits the aggregation of the magnetic nano particles and the agglomeration of the two-dimensional material, and the method is finishedThe method obtains the unique porous microspheres containing the dielectric-magnetic material interface, the micro/nano cross-scale structure and the 2D/0D multilevel heterostructure, remarkably enriches the electromagnetic loss form, improves the impedance matching and is beneficial to enhancing the microwave absorption.
3) The preparation method provided by the invention has mild process conditions, and is beneficial to batch preparation of the microwave absorbing material with light weight, wide bandwidth and high absorption strength.
Drawings
FIG. 1 shows MXene/GO porous microspheres and rGO/MXene/TiO in example 1 of the present invention 2 /Fe 2 And C, scanning electron microscope photos of the multi-stage heterostructure porous microspheres.
FIG. 2 shows MXene/GO porous microspheres and rGO/MXene/TiO in example 1 of the present invention 2 /Fe 2 And (3) a transmission electron microscope photo of the C multilevel heterostructure porous microsphere.
FIG. 3 shows rGO/MXene/TiO 2 obtained in example 1 of the present invention 2 /Fe 2 XRD pattern of C multilevel heterostructure porous microspheres.
FIG. 4 shows rGO/MXene/TiO polymers from example 2 of the invention 2 /Fe 2 And (3) a graph of the electromagnetic parameter of the C multi-stage heterostructure porous microsphere wave-absorbing material along with the change of frequency.
FIG. 5 shows the rGO/MXene/TiO mixtures of the invention obtained in example 1 2 /Fe 2 And C, a reflection loss chart of the multi-stage heterostructure porous microsphere wave-absorbing material.
FIG. 6 shows rGO/MXene/TiO 2 obtained in example 2 of the present invention 2 /Fe 2 And C, a reflection loss chart of the multi-stage heterostructure porous microsphere wave-absorbing material.
FIG. 7 shows rGO/MXene/TiO 2 obtained in example 3 of the present invention 2 /Fe 2 And C, a reflection loss chart of the multi-stage heterostructure porous microsphere wave-absorbing material.
FIG. 8 shows rGO/MXene/TiO prepared by comparative example of the present invention 2 /Fe 2 And C, a reflection loss chart of the multi-stage heterostructure porous microsphere wave-absorbing material.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
1) Preparing graphene oxide by using a Hummers method:
adding 2g of expanded graphite into a beaker filled with 100mL of concentrated sulfuric acid at room temperature, slowly adding 15g of potassium permanganate under an ice bath condition, transferring the mixture into a water bath at 50 ℃ for magnetic stirring reaction for 2 hours, after the reaction is finished, transferring the beaker into an ice water bath, adding 120mL of deionized water for dilution, and dropwise adding 10 mass percent of H 2 O 2 And (3) until no bubbles are generated, washing the supernatant with deionized water after standing, centrifuging the supernatant with the deionized water until the pH =7, and centrifuging and concentrating the supernatant for 1h at the rotating speed of 10000rpm to obtain Graphene Oxide (GO) for later use.
2) Etching Ti by using LiF-HCl system 3 AlC 2 MAX phase preparation of few-layer Ti 3 C 2 T x MXene suspension:
adding 3.2g of LiF into 40mL of hydrochloric acid solution with the concentration of 9mol/L, and uniformly stirring; 2g of Ti was added 3 AlC 2 (ii) a Reacting for 48 hours at the temperature of 40 ℃ and the stirring speed of 500 rpm; centrifuging and washing the product after the reaction is finished for 1min at 3500rpm, and circularly operating until the pH value of the supernatant is more than or equal to 6; collecting the precipitate, ultrasonically stripping in ice-water bath under inert atmosphere for 50min, centrifuging the ultrasonic product at 3000-4000 rpm for 30min, and collecting the supernatant to obtain Ti with less layer 3 C 2 T x MXene suspension.
3) According to the mass 2 of GO and MXnen solutes: 1 into deionized water, and stirring the two-dimensional material aqueous dispersion at a stirring speed of 500rpm for 1h, wherein the total concentration of the graphene oxide and the few-layer Mxene dispersion is 3 mg/mL.
4) The dispersion was charged into an atomizer whose air pump operation power was set to 20W and the flow rate of the atomized liquid ejected from the dispersion was 10mL/min, and the ejected droplets were collected in a container filled with liquid nitrogen. And collecting the frozen droplets, and freeze-drying the droplets for 48 hours in an environment at the temperature of-80 ℃ to obtain the GO/MXene porous microspheres.
5) The metallocene selected was ferrocene. Mixing 500mg of composite porous microspheres and 500mg of ferrocene in a planetary centrifugal mixer, transferring the mixture to a screw bottle, adding 140mg of carbon fiber, and reacting in a microwave reactor at 900W for 60S to obtain rGO/MXene/TiO 2 /Fe 2 C, multi-stage heterostructure porous microspheres.
Example GO/MXene porous microspheres and rGO/MXene/TiO 2 /Fe 2 A scanning electron micrograph of the C multi-stage heterostructure porous microsphere is shown in figure 1, and it can be seen from the figure that two-dimensional materials form a basic framework of the microsphere, a porous structure two-dimensional material nanosheet obtained after freeze drying is curled on the surface of the microsphere to form a fold, and magnetic nanoparticles are uniformly loaded on the surface of the two-dimensional material after microwave reaction by combining with a transmission electron micrograph 2, and in addition, GO is reduced and MXene is partially oxidized into TiO according to an X-ray diffraction diagram 2 And confirmed Fe 2 And C is present.
The rGO/MXene/TiO of the above example 2 /Fe 2 The C multi-stage heterostructure porous microsphere wave-absorbing material is mixed with paraffin according to the ratio of 5:95 mass ratio (i.e., 5wt% absorbent content) were uniformly mixed and pressed in a mold to prepare a standard coaxial ring sample (3.0 mm in inner diameter, 7.04mm in outer diameter, 2.0mm in thickness). Using a vector network analyser (ROHDE)&SCHWARZ ZNB 20) respectively test the electromagnetic parameters of the samples within 2-18GHz, and the test results are shown in figure 3, and the rGO/MXene/TiO can be known 2 /Fe 2 The C multilevel heterostructure porous microsphere has remarkable dielectric polarization loss characteristic in a frequency band of 2-18GHz and magnetic loss capacity.
According to the transmission line theory, based on the tested electromagnetic parameters, rGO/MXene/TiO with different thicknesses are obtained 2 /Fe 2 The wave-absorbing performance of the C multi-stage heterostructure porous microsphere wave-absorbing material is shown in figure 5, when the loading amount is 5wt% and the matching thickness is 3.5mm, the minimum reflection loss value of the composite wave-absorbing material is-54.3dB<The maximum effective absorption band of-10 dB is 5.68GHz (12.03-17.71 GH).
Example 2
1) Preparing graphene oxide by using a Hummers method:
adding 2g of expanded graphite into a beaker filled with 100mL of concentrated sulfuric acid at room temperature, slowly adding 15g of potassium permanganate under an ice bath condition, transferring the mixture into a water bath at 50 ℃ for magnetic stirring reaction for 2 hours, after the reaction is finished, transferring the beaker into an ice water bath, adding 120mL of deionized water for dilution, and dropwise adding 10 mass percent of H 2 O 2 And (3) until no bubbles are generated, washing the supernatant with deionized water after standing, centrifuging the supernatant with the deionized water until the pH =7, and centrifuging and concentrating the supernatant for 1h at the rotating speed of 10000rpm to obtain Graphene Oxide (GO) for later use.
2) Etching Ti by using LiF-HCl system 3 AlC 2 Preparation of few-layer Ti from MAX phase 3 C 2 T x MXene suspension:
adding 3.2g of LiF into 40mL of hydrochloric acid solution with the concentration of 9mol/L, and uniformly stirring; 2g of Ti were added 3 AlC 2 (ii) a Reacting for 48 hours at the temperature of 40 ℃ and the stirring speed of 500 rpm; centrifuging and washing the product after the reaction is finished at 3500rpm for 1min, and circularly operating until the pH value of the supernatant is more than or equal to 6; collecting the precipitate, ultrasonically stripping in ice-water bath under inert atmosphere for 50min, centrifuging the ultrasonic product at 3000-4000 rpm for 30min, and collecting the supernatant to obtain Ti with less layer 3 C 2 T x MXene suspension.
3) According to the mass 1 of GO and MXnen solutes: 1, dispersing the graphene oxide and the few-layer Mxene dispersion liquid into deionized water, enabling the total concentration of the two-dimensional material water dispersion liquid to be 3mg/mL, and stirring for 1h at a stirring speed of 500 rpm.
4) The dispersion was charged into an atomizer whose air pump operation power was set to 20W and the flow rate of the atomized liquid ejected from the dispersion was 10mL/min, and the ejected droplets were collected in a container filled with liquid nitrogen. And collecting the frozen small droplets, and freeze-drying for 48 hours in an environment at-80 ℃ to obtain GO/MXene porous microspheres.
5) The metallocene selected was ferrocene. 500mg of graphene oxide and 500mg of ferrocene are mixed in a planetary centrifugal mixer, transferred to a screw bottle, added with 140mg of carbon fiber and reacted in a microwave reactor at 900W for 60STo obtain rGO/MXene/TiO 2 /Fe 2 C, multi-stage heterostructure porous microspheres.
The rGO/MXene/TiO of the above example 2 /Fe 2 The C multi-stage heterostructure porous microsphere wave-absorbing material is mixed with paraffin according to the ratio of 5:95 mass ratio (i.e., 5wt% absorbent content) were uniformly mixed and pressed in a mold to prepare a standard coaxial ring sample (3.0 mm in inner diameter, 7.04mm in outer diameter, 2.0mm in thickness). Using a vector network analyser (ROHDE)&SCHWARZ ZNB 20) respectively test the electromagnetic parameters of the samples within 2-18GHz, as can be seen from the curves of FIG. 4 mu' and mu ″, fe 2 The introduction of C further leads to magnetic losses in the samples and, in addition, the abundance of defects in the microspheres and the strong polarization produced by the heterostructure of the packing units lead to relaxation peaks on the epsilon' and epsilon "curves for all samples. According to the transmission line theory, based on the tested electromagnetic parameters, rGO/MXene/TiO with different thicknesses are obtained 2 /Fe 2 The wave absorbing performance of the C multi-stage heterostructure porous microsphere wave absorbing material is shown in figure 6, when the loading is 5wt% and the matching thickness is 2.0mm, the minimum reflection loss value of the composite wave absorbing material is-67.4 dB<The maximum effective absorption band of-10 dB is 5.47GHz (11.94-17.41 GHz).
Example 3
1) Preparing graphene oxide by using a Hummers method:
adding 2g of expanded graphite into a beaker filled with 100mL of concentrated sulfuric acid at room temperature, then slowly adding 15g of potassium permanganate under the ice bath condition, transferring the mixture into a water bath at 50 ℃ for magnetic stirring reaction for 2 hours, after the reaction is finished, transferring the beaker into an ice water bath, adding 120mL of deionized water for dilution, and dropwise adding H with the mass fraction of 10% 2 O 2 And (3) until no bubbles are generated, washing the supernatant with deionized water after standing, and carrying out centrifugal concentration for 1h at the rotating speed of 10000rpm to obtain Graphene Oxide (GO) for later use.
2) Etching Ti by using LiF-HCl system 3 AlC 2 MAX phase preparation of few-layer Ti 3 C 2 T x MXene suspension:
adding 3.2g of LiF into 40mL of hydrochloric acid solution with the concentration of 9mol/L, and uniformly stirring; 2g of Ti were added 3 AlC 2 (ii) a At 40 ℃ ofReacting for 48 hours at the temperature and the stirring speed of 500 rpm; centrifuging and washing the product after the reaction is finished for 1min at 3500rpm, and circularly operating until the pH value of the supernatant is more than or equal to 6; collecting the precipitate, ultrasonically stripping in ice-water bath under inert atmosphere for 50min, centrifuging the ultrasonic product at 3000-4000 rpm for 30min, and collecting the supernatant to obtain Ti with less layer 3 C 2 T x MXene suspension.
3) According to the mass 1 of GO and MXene solutes: 3, dispersing the graphene oxide and the few-layer MXene dispersion liquid into deionized water at a stirring speed of 500rpm for 1h so that the total concentration of the two-dimensional material aqueous dispersion liquid is 3 mg/mL.
4) The dispersion was charged into an atomizer whose air pump operation power was set to 20W and the flow rate of the atomized liquid ejected from the dispersion was 10mL/min, and the ejected droplets were collected in a container filled with liquid nitrogen. And collecting the frozen droplets, and freeze-drying the droplets for 48 hours in an environment at the temperature of-80 ℃ to obtain the GO/MXene porous microspheres.
5) The metallocene selected was ferrocene. Mixing 500mg of graphene oxide and 500mg of ferrocene in a planetary centrifugal mixer, transferring the mixture to a screw bottle, adding 140mg of carbon fiber, and reacting in a microwave reactor at 900W for 60S to obtain rGO/MXene/TiO 2 /Fe 2 C, multi-stage heterostructure porous microspheres.
The rGO/MXene/TiO of the above example 2 /Fe 2 The C multi-stage heterostructure porous microsphere wave-absorbing material is mixed with paraffin according to the ratio of 5:95 mass ratio (i.e., 5wt% absorbent content) were uniformly mixed and pressed in a mold to prepare a standard coaxial ring sample (3.0 mm in inner diameter, 7.04mm in outer diameter, 2.0mm in thickness). Using a vector network analyser (ROHDE)&SCHWARZ ZNB 20) tested electromagnetic parameters of the samples within 2-18GHz, respectively. According to the transmission line theory, based on the tested electromagnetic parameters, rGO/MXene/TiO with different thicknesses are obtained 2 /Fe 2 The wave absorbing performance of the C multi-stage heterostructure porous microsphere wave absorbing material is shown in figure 7, when the loading is 5wt% and the matching thickness is 2mm, the minimum reflection loss value of the composite wave absorbing material is-35.1dB, RL is adopted<The maximum effective absorption band of-10 dB is 4.19GHz (12.04-16.23 GHz).
Comparative example 1
1) Preparing graphene oxide by using a Hummers method:
adding 2g of expanded graphite into a beaker filled with 100mL of concentrated sulfuric acid at room temperature, slowly adding 15g of potassium permanganate under an ice bath condition, transferring the mixture into a water bath at 50 ℃ for magnetic stirring reaction for 2 hours, after the reaction is finished, transferring the beaker into an ice water bath, adding 120mL of deionized water for dilution, and dropwise adding 10 mass percent of H 2 O 2 And (3) until no bubbles are generated, washing the supernatant with deionized water after standing, centrifuging the supernatant with the deionized water until the pH =7, and centrifuging and concentrating the supernatant for 1h at the rotating speed of 10000rpm to obtain Graphene Oxide (GO) for later use.
2) Etching Ti by using LiF-HCl system 3 AlC 2 MAX phase preparation of few-layer Ti 3 C 2 T x MXene suspension:
adding 3.2g of LiF into 40mL of hydrochloric acid solution with the concentration of 9mol/L, and uniformly stirring; 2g of Ti were added 3 AlC 2 (ii) a Reacting for 48 hours at the temperature of 40 ℃ and the stirring speed of 500 rpm; centrifuging and washing the product after the reaction is finished for 1min at 3500rpm, and circularly operating until the pH value of the supernatant is more than or equal to 6; collecting the precipitate, ultrasonically stripping in ice-water bath under inert atmosphere for 50min, centrifuging the ultrasonic product at 3000-4000 rpm for 30min, and collecting the supernatant to obtain Ti with less layer 3 C 2 T x MXene suspension.
3) According to the mass 1 of GO and MXnen solutes: 1 into deionized water, and stirring the two-dimensional material aqueous dispersion at a stirring speed of 500rpm for 1h, wherein the total concentration of the graphene oxide and the few-layer Mxene dispersion is 3 mg/mL.
4) The dispersion was charged into an atomizer whose air pump operation power was set to 20W and the flow rate of the atomized liquid ejected from the dispersion was 10mL/min, and the ejected droplets were collected in a container filled with liquid nitrogen. And collecting the frozen droplets, and freeze-drying the droplets for 48 hours in an environment at the temperature of-80 ℃ to obtain the GO/MXene porous microspheres.
Respectively mixing the GO/MXene porous microspheres of the above embodiment with paraffin according to the ratio of 5:95 mass ratio (i.e. 5wt% of absorbent content), pressing in a mold to obtain a standard coaxial ring sample (inner diameter of 3.0mm, outer diameter of 7.04mm, thickness of 2 mm)0 mm). Using a vector network analyser (ROHDE)&SCHWARZ ZNB 20) respectively testing the electromagnetic parameters of a sample within 2-18GHz, according to a transmission line theory, obtaining the wave absorbing performance of the GO/MXene porous microsphere wave absorbing material with different thicknesses based on the tested electromagnetic parameters as shown in figure 8, wherein when the loading amount is 10wt% and the matching thickness is 5.0mm, the minimum reflection loss value of the composite wave absorbing material is only-5.04 dB, and no effective absorption frequency band exists. Shows that the rGO/MXene/TiO is obtained by microwave reaction 2 /Fe 2 The electromagnetic wave absorption capacity of the C multi-stage heterostructure porous microsphere is far higher than that of the GO/MXene porous microsphere wave-absorbing material in the comparative example.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.
Claims (10)
1. rGO/MXene/TiO 2 /Fe 2 The preparation method of the C-stage heterostructure porous microsphere wave-absorbing material is characterized by comprising the following steps:
(1) Preparation of the dispersion: mixing Graphene Oxide (GO) and few-layer Ti 3 C 2 T x Dispersing the MXene suspension into deionized water, and uniformly stirring to obtain a water dispersion of the two-dimensional material;
(2) Preparing GO/MXene porous microspheres: loading the dispersion liquid into an atomizer, atomizing the dispersion liquid into a container filled with liquid nitrogen, collecting frozen droplets, and performing freeze drying treatment to obtain GO/MXene porous microspheres;
(3)rGO/MXene/TiO 2 /Fe 2 c, preparation of the porous microsphere with the multilevel heterostructure: grinding and mixing the porous microspheres and metallocene; adding carbon fiber into the mixture, and reacting in a microwave reactor at a fixed power in an argon atmosphere to finally obtain rGO/MXene/TiO 2 /Fe 2 C multilevel heterojunctionAnd (3) forming porous microspheres.
2. The rGO/MXene/TiO of claim 1 2 /Fe 2 The preparation method of the C-stage heterostructure porous microsphere wave-absorbing material is characterized in that in the step (1), the graphene oxide is synthesized by a Brodie method, a Staudenmaier method or a Hummers method.
3. The rGO/MXene/TiO of claim 1 2 /Fe 2 The preparation method of the C multi-stage heterostructure porous microsphere wave-absorbing material is characterized in that in the step (1), the few-layer Ti is adopted 3 C 2 T x Etching Ti in MXene suspension by using LiF-HCl system 3 C 2 T x MAX phase method preparation, including the following steps: adding LiF into a hydrochloric acid solution with the concentration of 9-10 mol/L to ensure that the concentration of LiF is 60-100 mg/mL, and uniformly stirring; adding Ti 3 C 2 T x And enabling the mass ratio of MAX phase to LiF to be 1: (2-4); reacting for 40-48h at the temperature of 40-50 ℃ and the stirring speed of 300-600 rpm; centrifugally washing the product after the reaction at 3000-4000 rpm for 1-2 min, and circularly operating until the pH value of the supernatant is more than or equal to 6; collecting the precipitate, ultrasonically stripping in ice-water bath under inert atmosphere for 40-60 min, centrifuging the ultrasonic product at 3000-4000 rpm for 20-35min, and collecting the supernatant to obtain Ti 3 C 2 T x MXene suspension.
4. The rGO/MXene/TiO of claim 3 2 /Fe 2 The preparation method of the C multi-stage heterostructure porous microsphere wave-absorbing material is characterized in that the MAX phase comprises Ti 3 AlC 2 、Ti 3 SiC 2 、Ti 2 AlC、Ti 2 SnC、Ti 2 SC、Ti 2 AlN、V 2 AlC、Ti 3 AlCN、Nb 2 AlC、Nb 2 SnC、Ta 2 Any one or the combination of more than two of AlC, and the corresponding MXene two-dimensional material comprises Ti 3 C 2 T x 、Ti 2 CT x 、Ti 2 NT x 、V 2 CT x 、Ti 3 CNT x 、Nb 2 CT x 、Ta 2 CT x Any one or a combination of two or more of them.
5. The rGO/MXene/TiO of claim 1 2 /Fe 2 The preparation method of the C multi-stage heterostructure porous microsphere wave-absorbing material is characterized in that in the step (1), the total concentration of the aqueous dispersion of the two-dimensional material is 2-6 mg/mL, GO and few layers of Ti 3 C 2 T x The solute mass ratio of MXene is 1: (0.3 to 3); the stirring speed is 300-600rpm, and the stirring time is 1-3h.
6. The rGO/MXene/TiO of claim 1 2 /Fe 2 The preparation method of the C multi-stage heterostructure porous microsphere wave-absorbing material is characterized in that in the step (2), the operation power of an air pump of an atomizer is 8W-25W, and the flow speed of atomized liquid sprayed by dispersion liquid is 10-30 mL/min.
7. The rGO/MXene/TiO of claim 1 2 /Fe 2 The preparation method of the C multi-stage heterostructure porous microsphere wave-absorbing material is characterized in that in the mixture in the step (3), the mass ratio of the microsphere is 40-50%, and the mass ratio of the metallocene is 50-60%; the type of the carbon fiber is any one of T300, T700 and T800, and the adding amount of the carbon fiber is 13-16% of the mass of the mixture.
8. The rGO/MXene/TiO of claim 1 2 /Fe 2 The preparation method of the C multi-stage heterostructure porous microsphere wave-absorbing material is characterized in that in the step (3), the fixed power of the microwave reaction is 700-1000W, and the reaction time is 70-120 s; the metallocene is ferrocene or a derivative thereof; the ferrocene derivatives are one or more of ferrocene formaldehyde, 1,1 '-diene bis (pinacol) borate, 1,1' -bis (diphenylphosphino) ferrocene, and nickel metallocene, cobalt metallocene and derivatives thereof.
9. The rGO/MXen of claim 1e/TiO 2 /Fe 2 The preparation method of the C multi-stage heterostructure porous microsphere wave-absorbing material is characterized in that a planetary centrifugal mixer is adopted for grinding and mixing in the step (3), the rotating speed is 800-1200 r/min, and the mixing time is 100-200 s.
10. An rGO/MXene/TiO prepared by the method of any one of claims 1 to 9 2 /Fe 2 C, a multi-stage heterostructure porous microsphere wave-absorbing material.
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