阅读说明：本技术 一种MXene/GO杂化气凝胶微球吸波剂及其制备方法 (MXene/GO hybrid aerogel microsphere wave absorbing agent and preparation method thereof ) 是由 周祚万 李颖 孟凡彬 梅园 王华高 于 2019-09-29 设计创作，主要内容包括：一种MXene/GO杂化气凝胶微球吸波剂及其制备方法,属于MXene材料技术领域。MXene/GO杂化气凝胶微球吸波剂是由氧化石墨烯和Ti<Sub>3</Sub>C<Sub>2</Sub>T<Sub>x</Sub> MXene形成的具有微观杂化片层结构的多孔微球,杂化片层结构包括面-面堆叠的氧化石墨烯和Ti<Sub>3</Sub>C<Sub>2</Sub>T<Sub>x</Sub> MXene纳米片。此MXene/GO杂化气凝胶微球吸波剂具有较好的吸波性能,能够应用于吸波领域。一种MXene/GO杂化气凝胶微球吸波剂的制备方法通过静电纺丝能够得到冷冻的两种分散液组装后的液滴,Ti<Sub>3</Sub>C<Sub>2</Sub>T<Sub>x</Sub> MXene与氧化石墨烯被快速生长的冰晶挤压到晶界处形成三维网络,干燥使冰晶升华得到具有多孔结构的微球。(The MXene/GO hybrid aerogel microsphere wave absorbing agent is a porous microsphere with a microscopic hybrid lamellar structure formed by graphene oxide and Ti 3 C 2 T x MXene, the hybrid lamellar structure comprises graphene oxide stacked in a surface-surface mode and Ti 3 C 2 T x MXene nanosheets, the MXene/GO hybrid aerogel microsphere wave absorbing agent has good wave absorbing performance and can be applied to the field of wave absorption.)

1. An MXene/GO hybrid aerogel microsphere wave absorbing agent, which is characterized in that the MXene/GO hybrid aerogel microsphere wave absorbing agent is a porous microsphere with a microscopic hybrid lamellar structure formed by graphene oxide and Ti ₃ C ₂ T _x MXene, and the hybrid lamellar structure comprises surface-to-surface stacked graphene oxide and Ti ₃ C ₂ T _x MXene nanosheets.

2. The MXene/GO hybrid aerogel microsphere wave absorbing agent according to claim 1, wherein the mass fraction of Ti ₃ C ₂ T _x MXene in the MXene/GO hybrid aerogel microsphere wave absorbing agent is 5-95%;

Optionally, the mass fraction of Ti ₃ C ₂ T _x MXene in the MXene/GO hybrid aerogel microsphere wave absorbing agent is 25-35%.

3. The MXene/GO hybrid aerogel microsphere wave absorbing agent according to claim 1, wherein the diameter of the microsphere is 100-500 μm, the thickness of the graphene oxide lamella is 1-3 nm, and the thickness of the Ti ₃ C ₂ T _x MXene lamella is 1-2 nm.

4. The preparation method of the MXene/GO hybrid aerogel microsphere wave absorbing agent according to any one of claims 1 to 3, wherein the preparation method of the MXene/GO hybrid aerogel microsphere wave absorbing agent comprises the steps of sequentially subjecting a mixed solution to electrostatic spinning and freezing treatment to obtain a frozen liquid droplet sample, and drying the liquid droplet sample to obtain MXene/GO hybrid aerogel microspheres;

the mixed solution is obtained by mixing graphene oxide nanosheet dispersion liquid and MXene nanosheet dispersion liquid.

5. The preparation method of the MXene/GO hybrid aerogel microsphere wave absorbing agent according to claim 4, wherein the concentration of the graphene oxide nanosheet dispersion is 4-15 mg/mL, and the concentration of the MXene nanosheet dispersion is 4-6 mg/mL.

6. the preparation method of the MXene/GO hybrid aerogel microsphere wave absorbing agent according to claim 4, wherein an oxygen-free environment is maintained during the preparation of the mixed solution by mixing the graphene oxide nanosheet dispersion and the MXene nanosheet dispersion.

7. The preparation method of the MXene/GO hybrid aerogel microsphere wave absorbing agent according to claim 4, wherein the mixed solution is prepared by mixing the graphene oxide nanosheet dispersion and the MXene nanosheet dispersion in an ice bath.

8. The preparation method of the MXene/GO hybrid aerogel microsphere wave absorber according to claim 4, wherein the freezing process comprises receiving the droplet sample obtained by electrospinning with liquid nitrogen.

9. The method for preparing the MXene/GO hybrid aerogel microsphere wave absorber of claim 4, wherein the drying comprises vacuum freeze drying;

Optionally, the drying time is 20-28 h.

10. The preparation method of the MXene/GO hybrid aerogel microsphere wave absorber according to claim 4, wherein the voltage during electrostatic spinning is 45-55 kV.

Technical Field

The application relates to the technical field of MXene materials, in particular to an MXene/GO hybrid aerogel microsphere wave absorbing agent and a preparation method thereof.

Background

in recent years, two-dimensional transition metal carbide/carbonitride (MXene) has been studied in a great deal because of its abundant surface functional groups, high specific surface area, high mechanical strength and electrical conductivity, and has been widely used in super capacitors, batteries, catalysis, sensors, molecular sieves, and electromagnetic shielding.

Disclosure of Invention

The application provides an MXene/GO hybrid aerogel microsphere wave absorbing agent and a preparation method thereof, wherein the MXene/GO hybrid aerogel microsphere wave absorbing agent can be prepared by a simple method, and the MXene/GO hybrid aerogel microsphere wave absorbing agent has good wave absorbing performance.

the embodiment of the application is realized as follows:

In a first aspect, the present application example provides an MXene/GO hybrid aerogel microsphere wave absorber, which is a porous microsphere formed of graphene oxide and Ti ₃ C ₂ T _x MXene and having a microscopic hybrid lamellar structure, the hybrid lamellar structure including a face-to-face stack of graphene oxide and Ti ₃ C ₂ T _x MXene nanosheet.

In the technical scheme, the MXene/GO hybrid aerogel microsphere wave absorbing agent has good wave absorbing performance and can be applied to the field of wave absorption. In addition, as MXene and graphene oxide have high-activity surfaces and abundant cavity structures, the hybrid microsphere also has adsorption capacity on heavy metal ions (chromium, lead, nickel, copper, mercury, zinc, cadmium, manganese and the like) and organic pollutants (methylene blue, Congo red and the like), and can be used for wastewater purification. MXene and graphene oxide nanosheets have good conductivity, and abundant cavity structures and hybrid structures of the MXene and graphene oxide nanosheets are beneficial to charge transfer and storage, and the hybrid microspheres can be used in the fields of energy conversion and storage (batteries and super capacitors) and catalysis.

With reference to the first aspect, in a first possible example of the first aspect of the present application, the mass fraction of Ti ₃ C ₂ T _x MXene in the MXene/GO hybrid aerogel microsphere wave absorber is 5-95%.

Optionally, the mass fraction of Ti ₃ C ₂ T _x MXene in the MXene/GO hybrid aerogel microsphere wave absorbing agent is 25-35%.

In the example, the MXene/GO hybrid aerogel microsphere wave absorbing agent can be prepared when the mass fraction of Ti ₃ C ₂ T _x MXene in the MXene/GO hybrid aerogel wave absorbing agent is 5-95%, and the wave absorbing performance of the MXene/GO hybrid aerogel is better when the mass fraction of Ti ₃ C ₂ T _x MXene in the MXene/GO hybrid aerogel is 25-35%.

In a second possible example of the first aspect of the present application, in combination with the first aspect, the microspheres have a diameter of 100 to 500 μm, a thickness of a graphene oxide sheet is 1 to 3nm, and a thickness of a Ti ₃ C ₂ T _x MXene sheet is 1 to 2 nm.

in a second aspect, the application example provides a preparation method of an MXene/GO hybrid aerogel microsphere wave absorbing agent, which comprises the steps of sequentially carrying out electrostatic spinning and freezing treatment on a mixed solution to obtain a frozen liquid drop sample, and drying the liquid drop sample to obtain the MXene/GO hybrid aerogel microsphere.

The mixed solution is obtained by mixing graphene oxide nanosheet dispersion liquid and MXene nanosheet dispersion liquid.

in the technical scheme, the liquid drop formed by assembling the frozen graphene oxide nanosheet dispersion liquid and the MXene nanosheet dispersion liquid can be obtained through electrostatic spinning, at the moment, Ti ₃ C ₂ T _x MXene and graphene oxide are extruded to a crystal boundary by rapidly growing ice crystals to form a three-dimensional network, and the ice crystals are dried to sublimate to obtain the microsphere with the porous structure.

The preparation method is simple and convenient, and the prepared MXene/GO hybrid aerogel microsphere wave absorbing agent has good stability and wave absorbing performance.

in combination with the second aspect, in a first possible example of the second aspect of the present application, the concentration of the graphene oxide nanosheet dispersion is 4-15 mg/mL, and the concentration of the MXene nanosheet dispersion is 4-6 mg/mL.

in the above example, the graphene oxide nanosheet dispersion and MXene nanosheet dispersion at the above concentrations were used to advantage in ejecting the sample as droplets during electrospinning, and too low and too high concentrations were not used to advantage in ejecting the sample as droplets during electrospinning.

In combination with the second aspect, in a second possible example of the second aspect of the present application, an oxygen-free environment is maintained during the preparation of the mixed solution by mixing the graphene oxide nanosheet dispersion and the MXene nanosheet dispersion.

In the above example, the graphene oxide nanosheets are easily oxidized at normal temperature, so that the mixed solution prepared in an oxygen-free environment can prevent oxygen in the air from deoxidizing the Ti ₃ C ₂ T _x MXene nanosheets, and the prepared MXene/GO hybrid aerogel microsphere wave absorber is guaranteed to have good and controllable performance.

In a third possible example of the second aspect of the present application in combination with the second aspect, the above-described graphene oxide nanosheet dispersion and MXene nanosheet dispersion are mixed in an ice bath to produce a mixed solution.

In the above example, the Ti ₃ C ₂ T _x MXene nanosheets are easily oxidized at normal temperature, but the Ti ₃ C ₂ T _x MXene nanosheets are not easily oxidized by air in a low-temperature environment, so that the Ti ₃ C ₂ T _x MXene nanosheets in the mixed liquid can be effectively prevented from being denatured, and the performance of the prepared MXene/GO hybrid aerogel microsphere wave absorbing agent is influenced.

In a fourth possible example of the second aspect of the present application in combination with the second aspect, the freezing process comprises receiving the above-mentioned droplet sample obtained by electrospinning with liquid nitrogen.

In the above example, liquid nitrogen can be snap frozen to fix the microspheres, and the rapid growth of ice crystals fixes the nanosheets in the microspheres at the grain boundaries.

In a fifth possible example of the second aspect of the present application in combination with the second aspect, the drying comprises vacuum freeze drying.

optionally, the drying time is 20-28 h.

In the above example, vacuum freeze drying can ensure that nanosheets in the microspheres are fixed at the grain boundaries, and after drying and water removal, microspheres with a microscopic hybrid lamellar structure formed by stacking graphene oxide and Ti ₃ C ₂ T _x MXene can be obtained.

In a sixth possible example of the second aspect of the present application in combination with the second aspect, the voltage at the time of electrospinning is 45 to 55 kV.

in the above example, the voltage of the electrospinning just enabled the sample of electrospun needles to aggregate into droplets.

drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.

FIG. 1 is a flow chart of preparation of MXene/GO hybrid aerogel microsphere wave absorbers provided in the examples of the present application;

fig. 2 is an atomic force microscope image of MXene and graphene oxide prepared in example 1 of the present application;

Fig. 3 is a scanning electron microscope image of the MXene/GO hybrid aerogel microsphere wave absorber prepared in example 2, the GO aerogel prepared in comparative example 1, and the MXene aerogel prepared in comparative example 2;

FIG. 4 is a transmission electron microscope image of MXene/GO hybrid aerogel microsphere wave absorbing agent prepared in example 3, GO aerogel prepared in comparative example 1, and MXene aerogel prepared in comparative example 2;

FIG. 5 shows a selected region for element distribution and content analysis of the MXene/GO hybrid aerogel microsphere wave absorber prepared in example 3 of the present application;

FIG. 6 is a diagram of element ratios in element distribution and content analysis of an MXene/GO hybrid aerogel microsphere wave absorber prepared in example 3 of the present application;

FIG. 7 is an X-ray diffraction spectrum of MXene/GO hybrid aerogel microsphere wave absorbing agent prepared in examples 1-9, GO aerogel prepared in comparative example 1, and MXene aerogel prepared in comparative example 2;

FIG. 8 is a graph showing the relationship between the MXene content X _M and the X-ray diffraction angle of an MXene/GO hybrid aerogel microsphere wave absorbing agent prepared in examples 1 to 9 of the application;

FIG. 9 is an X-ray diffraction pattern of an MXene/GO hybrid aerogel microsphere wave absorber of example 2 herein;

FIG. 10 is an X-ray diffraction pattern of an MXene/GO hybrid aerogel microsphere absorber of example 1 herein;

FIG. 11 is an X-ray diffraction pattern of an MXene/GO hybrid aerogel microsphere absorber of example 9 herein;

FIG. 12 is a structural evolution machine diagram of an embodiment of the present application;

FIG. 13 is an X-ray photoelectron spectroscopy analysis chart of MXene/GO hybrid aerogel microsphere wave absorbing agent prepared in example 1, GO aerogel prepared in comparative example 1 and MXene aerogel prepared in comparative example 2;

FIG. 14 is a high resolution spectrum of X-ray photoelectron spectroscopy analysis C1s of MXene/GO hybrid aerogel microsphere wave absorbers prepared in example 1, GO aerogel prepared in comparative example 1, and MXene aerogel prepared in comparative example 2 of the present application;

Fig. 15 is a raman spectrum of an MXene/GO hybrid aerogel microsphere wave absorber prepared in example 1, a GO aerogel prepared in comparative example 1, and an MXene aerogel prepared in comparative example 2 of the present application;

FIG. 16 is a partial enlarged view of the Raman spectra of MXene/GO hybrid aerogel microsphere wave absorbing agent prepared in example 1 and MXene aerogel prepared in comparative example 2;

FIG. 17 is a graph of the real part of the complex dielectric constant of MXene/GO hybrid aerogel microsphere wave absorbers prepared in examples 1, 4, 7 and 9, GO aerogel prepared in comparative example 1 and MXene aerogel prepared in comparative example 2;

FIG. 18 is a graph of the imaginary components of the complex dielectric constants of MXene/GO hybrid aerogel microsphere wave absorbers prepared in examples 1, 4, 7 and 9, GO aerogel prepared in comparative example 1 and MXene aerogel prepared in comparative example 2;

FIG. 19 is a Cole-Cole curve of MXene/GO hybrid aerogel microsphere wave absorbers made in examples 1, 4, 7, 9, comparative example 1, and comparative example 2 of the present application;

fig. 20 is a graph of loss factors for MXene/GO hybrid aerogel microsphere wave absorbers made in examples 1, 4, 7, 9, comparative example 1, and comparative example 2 of the present application;

fig. 21 is a graph of dielectric loss factor for the MXene/GO hybrid aerogel microsphere wave absorbers prepared in examples 1, 4, 7, and 9, the GO aerogel prepared in comparative example 1, and the MXene aerogel prepared in comparative example 2 of the present application;

FIG. 22 is a partially enlarged Cole-Cole curve of an MXene/GO hybrid aerogel microsphere wave absorber prepared in example 1 of the present application;

FIG. 23 is a delta diagram of MXene/GO hybrid aerogel microsphere wave absorbers prepared in examples 1, 4, 7 and 9, GO aerogel prepared in comparative example 1 and MXene aerogel prepared in comparative example 2 when the thickness is 0.5-5 mm;

FIG. 24 is a reflection loss graph of MXene/GO hybrid aerogel microsphere wave absorbing agent prepared in examples 1, 4, 7 and 9, GO aerogel prepared in comparative example 1 and MXene aerogel prepared in comparative example 2 when the thickness is 0.5-5 mm.

Detailed Description

Embodiments of the present application will be described in detail below with reference to examples, but those skilled in the art will appreciate that the following examples are only illustrative of the present application and should not be construed as limiting the scope of the present application. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

the following specific description is provided for an MXene/GO hybrid aerogel microsphere wave absorbing agent and a preparation method thereof in the embodiments of the present application:

The application provides an MXene/GO hybrid aerogel microsphere wave absorbing agent, and the MXene/GO hybrid aerogel microsphere wave absorbing agent is a porous microsphere with a microscopic hybrid lamellar structure, which is formed by mutually stacking Graphene Oxide (GO) and Ti ₃ C ₂ T _x MXene.

the MXene/GO hybrid aerogel microsphere wave absorbing agent has good wave absorbing performance and can be applied to the field of wave absorption.

MXene is a two-dimensional transition metal carbide/carbonitride, in the examples herein, two-dimensional transition metal carbides are used, and the MXene surface has abundant surface functional groups, i.e., T is functional group in Ti ₃ C ₂ T _x.

The present application does not limit the kind of functional groups in Ti ₃ C ₂ T _x, where T may be O, OH, F.

the diameter of the microsphere is 100-500 mu m, the thickness of a graphene oxide lamella in the microsphere is 1-3 mm, the diameter is 10 ¹ mu m, and the thickness of a Ti ₃ C ₂ T _x MXene lamella in the microsphere is 1-2 nm.

The graphene oxide and Ti ₃ C ₂ T _x MXene are contained in the microsphere under an ideal state, and when the mass fraction of the Ti ₃ C ₂ T _x MXene in the microsphere is 5-95%, the MXene/GO hybrid aerogel microsphere wave absorbing agent can be prepared.

Optionally, the mass fraction of Ti ₃ C ₂ T _x MXene in the microsphere is 25-35%;

Optionally, the mass fraction of Ti ₃ C ₂ T _x MXene in the microsphere is 28-32%.

When the mass fraction of Ti ₃ C ₂ T _x MXene in the microspheres is 25-35%, the wave absorbing performance of the MXene/GO hybrid aerogel microsphere wave absorbing agent is good.

The application also provides a preparation method of the MXene/GO hybrid aerogel microsphere wave absorbing agent, which comprises the steps of sequentially carrying out electrostatic spinning and freezing treatment on the mixed solution to obtain a frozen liquid drop sample, and drying the liquid drop sample to obtain the MXene/GO hybrid aerogel microsphere.

The mixed solution is obtained by mixing graphene oxide nanosheet dispersion liquid and MXene nanosheet dispersion liquid.

Fig. 1 is a flow chart of a preparation method of an MXene/GO hybrid aerogel microsphere wave absorbing agent, as shown in fig. 1, a Ti ₃ C ₂ T _x MXene surface is a hydrophilic surface and can be sufficiently dissolved in water, when a graphene oxide solution with the same property is dripped, a Ti ₃ C ₂ T _x MXene nanosheet can be well compatible and assembled with a GO nanosheet under appropriate stirring, an assembled droplet is obtained through electrostatic spinning, the droplet is frozen and shaped by liquid nitrogen immediately, a hybrid nanosheet layer consisting of the Ti ₃ C ₂ T _x MXene and GO is extruded to a grain boundary by rapidly growing ice crystals to form a three-dimensional network, and the MXene/GO hybrid aerogel microsphere can be obtained through freeze drying.

The source of the graphene oxide nanosheet dispersion and the Ti ₃ C ₂ T _x MXene nanosheet dispersion are not limited in the embodiments of the present application and can be purchased directly or prepared by themselves.

The preparation method of the graphene oxide nanosheet dispersion liquid comprises the following steps:

1.5g of large-scale graphite is slowly added into a mixed solution of concentrated sulfuric acid and concentrated phosphoric acid (180mL +20mL), stirred in an ice bath, and then 9g of potassium permanganate is slowly added in batches, wherein the temperature is controlled not to exceed 40 ℃ in the whole process. After the potassium permanganate is added, the system is heated to 60 ℃ and stirred for 12 hours. The resulting dark green solution was then slowly poured into ice water and stirred dropwise with hydrogen peroxide until the solution turned bright yellow. Adding 5% HCl solution, performing suction filtration and washing for 5 times, then performing centrifugal washing by using deionized water until the pH value is about 7, and removing the lower black precipitate to obtain the graphene oxide nanosheet dispersion liquid with the concentration of 4-15 mg/mL.

the preparation method of the Ti ₃ C ₂ T _x MXene nanosheet dispersion liquid comprises the following steps:

Slowly dissolving 1.6g of lithium fluoride in 20mL of 9M hydrochloric acid, stirring for 5min, slowly adding 1g of Ti ₃ C ₂ T _x (10 min for use), stirring for 24h at room temperature, washing with deionized water, centrifuging at the centrifugal speed of 3500rpm for 5min each time, centrifuging for 6-8 times approximately to enable the pH of the solution to be higher than 6, collecting the precipitate, dissolving the precipitate in 100mL of water, performing ultrasonic treatment at 200W for 3h under the protection of argon gas, finally centrifuging at 3500rpm for 1h, and collecting the supernatant to obtain the Ti ₃ C ₂ T _x MXene nanosheet dispersion liquid with the concentration of 4-6 mg/mL.

Respectively preparing or purchasing a graphene oxide nanosheet dispersion liquid and a Ti ₃ C ₂ T _x MXene nanosheet dispersion liquid, slowly dripping the graphene oxide nanosheet dispersion liquid into the Ti ₃ C ₂ T _x MXene nanosheet dispersion liquid to prepare a mixed liquid, and adding ultrapure water to adjust the concentration of the mixed liquid when necessary.

The mass ratio of the Ti ₃ C ₂ T _x MXene nanosheets to the sum of the mass of the graphene oxide nanosheets and the mass of the Ti ₃ C ₂ T _x MXene nanosheets in the prepared mixed solution is 5: 100-95: 100, so that the mass fraction of the Ti ₃ C ₂ T _x MXene in the prepared MXene/GO hybrid aerogel microsphere wave absorbing agent is 5-95%.

It should be noted that in the process of mixing the graphene oxide nanosheet dispersion liquid and the Ti ₃ C ₂ T _x MXene nanosheet dispersion liquid, in order to prevent the graphene oxide nanosheets from being oxidized, the mixing is generally performed in an oxygen-free environment or in an ice bath, the graphene oxide nanosheets are not easily oxidized in a low-temperature environment, and the graphene oxide nanosheet dispersion liquid can be ensured not to be denatured during mixing, so that the performance of the prepared MXene/GO hybrid aerogel microsphere wave absorbing agent is ensured.

Injecting the prepared mixed solution into an injector, and starting electrostatic spinning, wherein the voltage of the electrostatic spinning is 45-55 kV, and the voltage of the electrostatic spinning just enables a sample of a needle of the electrostatic spinning to be gathered into a droplet shape;

optionally, the voltage of electrostatic spinning is 48-52 kV;

Optionally, the voltage of electrospinning is 50 kV.

In order to ensure that a liquid drop sample prepared by electrostatic spinning can be frozen quickly, a receiving device of the electrostatic spinning is immersed in liquid nitrogen, the liquid nitrogen can directly receive the liquid drop sample obtained by the electrostatic spinning, the liquid drop sample is frozen quickly to fix the microspheric shape, and the nanosheets in the microspheres are fixed at the grain boundary.

Transferring the liquid drop sample frozen in the liquid nitrogen into a vacuum freeze dryer for real freeze drying, wherein the drying time is 20-28 h, and obtaining the MXene/GO hybrid aerogel microsphere wave absorbing agent after drying.

The MXene/GO hybrid aerogel microsphere wave absorber and the preparation method thereof of the present application are further described in detail with reference to the following examples.