阅读说明：本技术 一种具有窄薄尺寸的磁性石墨烯的制备方法 (Preparation method of magnetic graphene with narrow and thin size ) 是由 王志江 陈诚 李双军 于 2021-08-16 设计创作，主要内容包括：一种具有窄薄尺寸的磁性石墨烯的制备方法,它涉及一种磁性石墨烯的制备方法。本发明要解决现有磁性石墨烯工艺复杂、成本高、磁性粒子结合不好、尺寸大,并且很难产业化的问题。制备方法：一、制备氧化石墨烯前驱体；二、制备干燥的粉末；三、制备还原氧化石墨烯前驱体；四、制备负载磁性粒子的磁性石墨烯粉体；五、热处理。本发明用于具有窄薄尺寸的磁性石墨烯的制备。(A preparation method of magnetic graphene with narrow and thin dimensions relates to a preparation method of magnetic graphene. The invention aims to solve the problems that the existing magnetic graphene is complex in process, high in cost, poor in magnetic particle combination, large in size and difficult to industrialize. The preparation method comprises the following steps: firstly, preparing a graphene oxide precursor; secondly, preparing dry powder; thirdly, preparing a reduced graphene oxide precursor; fourthly, preparing magnetic graphene powder loaded with magnetic particles; and fifthly, heat treatment. The preparation method is used for preparing the magnetic graphene with narrow and thin size.)

1. A preparation method of magnetic graphene with narrow and thin dimension is characterized by comprising the following steps:

suspending a carbon-based raw material in an oxidant solution at the temperature of 20-100 ℃, soaking for 12-48 h, washing and drying to obtain a graphene oxide precursor;

dispersing a graphene oxide precursor in deionized water to obtain a graphene oxide precursor solution, and freeze-drying the graphene oxide precursor solution for 12-48 h at the temperature of-50-20 ℃ to obtain dried powder;

thirdly, placing the dried powder into a reducing agent solution at the temperature of 20-100 ℃, soaking for 12-48 h, washing and drying to obtain a reduced graphene oxide precursor;

adding the reduced graphene oxide precursor into an aqueous solution of a metal salt, adjusting the pH to 9-11, stirring and dispersing for 1-12 h under the conditions of inert gas and temperature of 80-280 ℃, adjusting the pH to 6-8, cooling and washing to obtain magnetic graphene powder loaded with magnetic particles;

the aqueous solution of the metal salt is an aqueous solution of ferric salt, an aqueous solution of cobalt salt or an aqueous solution of nickel salt;

fifthly, drying the magnetic graphene powder loaded with the magnetic particles for 12-48 h at the temperature of 60-80 ℃, and then carrying out heat treatment for 1-2 h at the temperature of 400-800 ℃ in an argon atmosphere to obtain the magnetic graphene with narrow and thin size.

2. The method according to claim 1, wherein the carbon-based material in the step one is single-walled carbon nanotube, multi-walled carbon nanotube or Y-shaped carbon nanotube.

3. The method according to claim 1, wherein the oxidant solution in the first step is one or a mixture of two of 5-10% by weight of hydrogen peroxide solution, 5-20% by weight of potassium permanganate solution, 70-98% by weight of concentrated sulfuric acid, or 35-38% by weight of concentrated nitric acid solution.

4. The method according to claim 1, wherein the reducing agent solution in step three is a hydrazine hydrate solution with a mass percentage of 20% to 80%, a formaldehyde solution with a mass percentage of 30% to 60%, or a sodium borohydride solution with a mass percentage of 1% to 10%.

5. The method according to claim 1, wherein the inert gas in step four is nitrogen or argon.

6. The method according to claim 1, wherein the aqueous solution of the metal salt in the fourth step is 5 to 10% by mass.

7. The method for preparing magnetic graphene with narrow and thin dimensions according to claim 1, wherein the iron salt in step four is one or a mixture of two of ferrous chloride, ferric acetylacetonate, ferrous nitrate and ferric nitrate; the cobalt salt in the fourth step is one or a mixture of two of cobalt chloride and cobalt nitrate; the nickel salt in the fourth step is one or a mixture of two of nickel chloride and nickel nitrate hexahydrate.

8. The method for preparing magnetic graphene with narrow and thin dimensions according to claim 1, wherein in the fourth step, the temperature is raised to 80 ℃ to 280 ℃ under the condition of inert gas and temperature raising rate of 2 ℃/min to 3 ℃/min, and then the mixture is stirred and dispersed for 1h to 12h under the condition of inert gas and temperature of 80 ℃ to 280 ℃.

9. The method for preparing magnetic graphene with narrow and thin dimension according to claim 1, wherein the mass ratio of the carbon-based raw material to the oxidant solution in the step one is 1 (10-100); the mass ratio of the graphene oxide precursor to the deionized water in the second step is 1 (10-100); the mass ratio of the dried powder to the reducing agent solution in the third step is 1 (20-100); the mass ratio of the reduced graphene oxide precursor to the aqueous solution of the metal salt in the fourth step is 1 (10-500).

10. The method according to claim 1, wherein the washing agent used in the washing in the step one is one or two of deionized water, ethanol and ethyl acetate; the detergent used for washing in the third step is one or two of deionized water and ethanol; and the detergent used for washing in the fourth step is one or two of deionized water and ethanol.

Technical Field

The invention relates to a preparation method of magnetic graphene.

Background

The graphene is used as the thinnest carbon material, has the characteristics of light weight, large specific surface area, high conductivity, abundant surface defects and the like, and is sp-based²The hybridized and connected carbon atoms are tightly packed into a single-layer two-dimensional honeycomb-shaped lattice structure, and the structure can be used for basic industry, biomedicine, drug delivery, advanced energy sources,The method has important application prospect in the aspects of micro-nano processing and the like. In order to prepare a better graphene-based material, graphene and magnetic nanoparticles are combined and assembled into magnetic graphene, so that the original physical and chemical excellent properties of the graphene are retained, and the material is endowed with magnetism, so that the material can be applied to the fields of electromagnetic shielding, adsorption, sewage treatment, medicines, biosensors and the like. However, the existing magnetic graphene has the disadvantages of complex process, high cost, poor magnetic particle combination, large size and difficult industrialization.

Disclosure of Invention

The invention provides a preparation method of magnetic graphene with a narrow and thin size, and aims to solve the problems that the existing magnetic graphene is complex in process, high in cost, poor in magnetic particle combination, large in size and difficult to industrialize.

A preparation method of magnetic graphene with narrow and thin dimension comprises the following steps:

suspending a carbon-based raw material in an oxidant solution at the temperature of 20-100 ℃, soaking for 12-48 h, washing and drying to obtain a graphene oxide precursor;

dispersing a graphene oxide precursor in deionized water to obtain a graphene oxide precursor solution, and freeze-drying the graphene oxide precursor solution for 12-48 h at the temperature of-50-20 ℃ to obtain dried powder;

thirdly, placing the dried powder into a reducing agent solution at the temperature of 20-100 ℃, soaking for 12-48 h, washing and drying to obtain a reduced graphene oxide precursor;

adding the reduced graphene oxide precursor into an aqueous solution of a metal salt, adjusting the pH to 9-11, stirring and dispersing for 1-12 h under the conditions of inert gas and temperature of 80-280 ℃, adjusting the pH to 6-8, cooling and washing to obtain magnetic graphene powder loaded with magnetic particles;

the aqueous solution of the metal salt is an aqueous solution of ferric salt, an aqueous solution of cobalt salt or an aqueous solution of nickel salt;

fifthly, drying the magnetic graphene powder loaded with the magnetic particles for 12-48 h at the temperature of 60-80 ℃, and then carrying out heat treatment for 1-2 h at the temperature of 400-800 ℃ in an argon atmosphere to obtain the magnetic graphene with narrow and thin size.

The invention has the beneficial effects that:

the invention provides a preparation method of magnetic graphene with narrow and thin dimensions, which is applied to the application fields of wave absorption, environment, flexible matrix materials and the like. The preparation method comprises the steps of taking carbon-based raw materials (carbon nanotubes and multi-walled carbon nanotubes) as carbon sources, preparing graphene by an oxidation-reduction method, then loading magnetic particles to prepare a magnetic graphene material, and controlling a preparation process to obtain the magnetic graphene with small width, excellent transverse-longitudinal ratio and stable and uniform appearance. The chemical analysis result proves that the magnetic graphene is successfully prepared, and the magnetic particles are well combined with the graphene substrate.

The concrete effects are as follows:

1. the operation is simple, the requirement on equipment is low, and large-scale industrial production can be realized;

2. the obtained product has high purity, and the narrow and thin magnetic graphene with the width of 100-200 nm and high transverse-longitudinal ratio can be obtained according to raw materials and process regulation;

3. according to different valence states, types and proportions of iron, cobalt or nickel salts, the size and the type of magnetic particles loaded on the surface of the magnetic graphene can be regulated, and the magnetic particles and the graphene have stronger interaction and are better combined.

4. The prepared magnetic graphene has good electromagnetic shielding performance, and the minimum absorption loss value in the range of 2 GHz-18 GHz can reach-66 dB, namely 99% of electromagnetic waves can be absorbed.

The invention provides a preparation method of magnetic graphene with narrow and thin dimensions.

Drawings

Fig. 1 is an X-ray diffraction pattern of magnetic graphene with narrow and thin dimensions prepared in example one, wherein 1 is graphene, and 2 is ferroferric oxide;

fig. 2 is a transmission electron micrograph, (a) is a TEM image of a reduced graphene oxide precursor prepared in example one step three, (b) is a TEM image of magnetic graphene with a narrow thin dimension prepared in example one, (c) is a HRTEM image of magnetic graphene with a narrow thin dimension prepared in example one;

fig. 3 is a raman spectrum of magnetic graphene with a narrow and thin dimension prepared in example one;

fig. 4 is a hysteresis loop diagram of magnetic graphene with narrow and thin dimensions prepared in the first embodiment;

fig. 5 is a block diagram of electromagnetic wave absorption energy of a wave absorber with different thicknesses tested by a coaxial method after uniformly mixing narrow and thin magnetic graphene prepared in the first embodiment with a paraffin matrix, where 1 is the wave absorption performance of the wave absorber with a thickness of 5.0mm, 2 is the wave absorption performance of the wave absorber with a thickness of 4.5mm, 3 is the wave absorption performance of the wave absorber with a thickness of 4.0mm, 4 is the wave absorption performance of the wave absorber with a thickness of 3.5mm, 5 is the wave absorption performance of the wave absorber with a thickness of 3.0mm, 6 is the wave absorption performance of the wave absorber with a thickness of 2.5mm, 7 is the wave absorption performance of the wave absorber with a thickness of 2.0mm, and 8 is the wave absorption performance of the wave absorber with a thickness of 2.25 mm.

Detailed Description

The first embodiment is as follows: the preparation method of the magnetic graphene with the narrow and thin dimension is carried out according to the following steps:

suspending a carbon-based raw material in an oxidant solution at the temperature of 20-100 ℃, soaking for 12-48 h, washing and drying to obtain a graphene oxide precursor;

dispersing a graphene oxide precursor in deionized water to obtain a graphene oxide precursor solution, and freeze-drying the graphene oxide precursor solution for 12-48 h at the temperature of-50-20 ℃ to obtain dried powder;

thirdly, placing the dried powder into a reducing agent solution at the temperature of 20-100 ℃, soaking for 12-48 h, washing and drying to obtain a reduced graphene oxide precursor;

adding the reduced graphene oxide precursor into an aqueous solution of a metal salt, adjusting the pH to 9-11, stirring and dispersing for 1-12 h under the conditions of inert gas and temperature of 80-280 ℃, adjusting the pH to 6-8, cooling and washing to obtain magnetic graphene powder loaded with magnetic particles;

the aqueous solution of the metal salt is an aqueous solution of ferric salt, an aqueous solution of cobalt salt or an aqueous solution of nickel salt;

fifthly, drying the magnetic graphene powder loaded with the magnetic particles for 12-48 h at the temperature of 60-80 ℃, and then carrying out heat treatment for 1-2 h at the temperature of 400-800 ℃ in an argon atmosphere to obtain the magnetic graphene with narrow and thin size.

The principle is as follows: in the embodiment, reduced graphene oxide is prepared by stripping carbon nanotube-based raw materials by using a redox method, oxygen-containing functional groups are introduced to the surface of the carbon nanotube-based raw materials under the action of an oxidant, so that the van der waals force in the structure is weakened, the interaction force between the carbon nanotube-based raw materials and water molecules is enhanced, the carbon nanotube is unfolded and cracked, the stripping of graphene is realized, the oxygen-containing functional groups on the surface are removed by using a chemical reduction method, and finally, magnetic particles are loaded on the surface of the reduced graphene oxide material by using a solution coprecipitation method, so that the well-combined magnetic graphene material is obtained. Graphene is stripped through selection of carbon nanotube raw materials, and graphene precursors based on the transverse-longitudinal ratio of the raw materials are stripped from carbon nanotubes with different shapes under the action of oxidation reduction.

The beneficial effects of the embodiment are as follows:

the embodiment provides a preparation method of magnetic graphene with narrow and thin size, and the preparation method is applied to the application fields of wave absorption, environment, flexible base materials and the like. The preparation method comprises the steps of taking carbon-based raw materials (carbon nanotubes and multi-walled carbon nanotubes) as carbon sources, preparing graphene by an oxidation-reduction method, then loading magnetic particles to prepare a magnetic graphene material, and controlling a preparation process to obtain the magnetic graphene with small width, excellent transverse-longitudinal ratio and stable and uniform appearance. The chemical analysis result proves that the magnetic graphene is successfully prepared, and the magnetic particles are well combined with the graphene substrate.

The concrete effects are as follows:

1. the operation is simple, the requirement on equipment is low, and large-scale industrial production can be realized;

2. the obtained product has high purity, and the narrow and thin magnetic graphene with the width of 100-200 nm and high transverse-longitudinal ratio can be obtained according to raw materials and process regulation;

3. according to different valence states, types and proportions of iron, cobalt or nickel salts, the size and the type of magnetic particles loaded on the surface of the magnetic graphene can be regulated, and the magnetic particles and the graphene have stronger interaction and are better combined.

4. The prepared magnetic graphene has good electromagnetic shielding performance, and the minimum absorption loss value in the range of 2 GHz-18 GHz can reach-66 dB, namely 99% of electromagnetic waves can be absorbed.

The second embodiment is as follows: the first difference between the present embodiment and the specific embodiment is: the carbon-based raw material in the step one is a single-walled carbon nanotube, a multi-walled carbon nanotube or a Y-shaped carbon nanotube. The rest is the same as the first embodiment.

The third concrete implementation mode: this embodiment is different from the first or second embodiment in that: the oxidant solution in the first step is one or a mixture of two of 5-10% by mass of hydrogen peroxide solution, 5-20% by mass of potassium permanganate solution, 70-98% by mass of concentrated sulfuric acid or 35-38% by mass of concentrated nitric acid solution. The other is the same as in the first or second embodiment.

The fourth concrete implementation mode: the difference between this embodiment mode and one of the first to third embodiment modes is: the reducing agent solution in the third step is 20-80% of hydrazine hydrate solution, 30-60% of formaldehyde solution or 1-10% of sodium borohydride solution. The other is the same as in the first or second embodiment.

The fifth concrete implementation mode: the difference between this embodiment and one of the first to fourth embodiments is: and fourthly, the inert gas is nitrogen or argon. The rest is the same as the first to fourth embodiments.

The sixth specific implementation mode: the difference between this embodiment and one of the first to fifth embodiments is: the mass percentage of the aqueous solution of the metal salt in the step four is 5-10%. The rest is the same as the first to fifth embodiments.

The seventh embodiment: the difference between this embodiment and one of the first to sixth embodiments is: the ferric salt in the fourth step is one or a mixture of two of ferrous chloride, ferric acetylacetonate, ferrous nitrate and ferric nitrate; the cobalt salt in the fourth step is one or a mixture of two of cobalt chloride and cobalt nitrate; the nickel salt in the fourth step is one or a mixture of two of nickel chloride and nickel nitrate hexahydrate. The others are the same as the first to sixth embodiments.

The specific implementation mode is eight: the present embodiment differs from one of the first to seventh embodiments in that: in the fourth step, the temperature is raised to 80-280 ℃ under the conditions of inert gas and temperature raising rate of 2-3 ℃/min, and then the mixture is stirred and dispersed for 1-12 h under the conditions of inert gas and temperature of 80-280 ℃. The rest is the same as the first to seventh embodiments.

The specific implementation method nine: the present embodiment differs from the first to eighth embodiments in that: the mass ratio of the carbon-based raw material to the oxidant solution in the first step is 1 (10-100); the mass ratio of the graphene oxide precursor to the deionized water in the second step is 1 (10-100); the mass ratio of the dried powder to the reducing agent solution in the third step is 1 (20-100); the mass ratio of the reduced graphene oxide precursor to the aqueous solution of the metal salt in the fourth step is 1 (10-500). The other points are the same as those in the first to eighth embodiments.

The detailed implementation mode is ten: the present embodiment differs from one of the first to ninth embodiments in that: the detergent used for washing in the step one is one or two of deionized water, ethanol and ethyl acetate; the detergent used for washing in the third step is one or two of deionized water and ethanol; and the detergent used for washing in the fourth step is one or two of deionized water and ethanol. The other points are the same as those in the first to ninth embodiments.

The following examples were used to demonstrate the beneficial effects of the present invention:

the first embodiment is as follows:

a preparation method of magnetic graphene with narrow and thin dimension comprises the following steps:

suspending a carbon-based raw material in an oxidant solution at the temperature of 20 ℃, soaking for 24 hours, washing and drying to obtain a graphene oxide precursor;

dispersing the graphene oxide precursor in deionized water to obtain a graphene oxide precursor solution, and freeze-drying the graphene oxide precursor solution for 48 hours at the temperature of-48 ℃ to obtain dried powder;

thirdly, placing the dried powder in a reducing agent solution at the temperature of 90 ℃, soaking for 24 hours, washing and drying to obtain a reduced graphene oxide precursor;

adding the reduced graphene oxide precursor into an aqueous solution of metal salt, adjusting the pH to 10, stirring and dispersing for 1h under the conditions of inert gas and the temperature of 280 ℃, adjusting the pH to 7, cooling and washing to obtain magnetic graphene powder loaded with magnetic particles;

the aqueous solution of the metal salt is an aqueous solution of iron salt;

fifthly, drying the magnetic graphene powder loaded with the magnetic particles for 12 hours at the temperature of 80 ℃, and then carrying out heat treatment for 2 hours at the temperature of 500 ℃ in an argon atmosphere to obtain the magnetic graphene with narrow and thin size.

The carbon-based raw material in the step one is a multi-wall carbon nano tube.

The oxidant solution in the step one is a mixture of 10% by mass of hydrogen peroxide solution and 5% by mass of potassium permanganate solution, and the volume ratio of the 10% by mass of hydrogen peroxide solution to the 5% by mass of potassium permanganate solution is 10: 1.

The reducing agent solution in the third step is 80% hydrazine hydrate solution by mass percent.

And fourthly, the inert gas is argon.

The mass percentage of the aqueous solution of the metal salt described in the fourth step is 5%.

The ferric salt in the fourth step is ferric acetylacetonate.

In the fourth step, the temperature is raised to 280 ℃ under the conditions of inert gas and the heating rate of 3 ℃/min, and then the mixture is stirred and dispersed for 1h under the conditions of inert gas and the temperature of 280 ℃.

The mass ratio of the carbon-based raw material to the oxidant solution in the step one is 1: 100; the mass ratio of the graphene oxide precursor to the deionized water in the step two is 1: 100; the mass ratio of the dried powder to the reducing agent solution in the third step is 1: 100; the mass ratio of the reduced graphene oxide precursor to the aqueous solution of the metal salt in the fourth step is 1: 20;

the washing agent used in the step one is ethyl acetate and ethanol;

the detergent used for washing in the third step is deionized water and ethanol;

the detergents used for washing in the fourth step are deionized water and ethanol.

Fig. 1 is an X-ray diffraction pattern of magnetic graphene with narrow and thin dimensions prepared in example one, wherein 1 is graphene, and 2 is ferroferric oxide; according to the figure, the loaded particles obtained by analysis in the XRD spectrum are ferroferric oxide, the particle size of the ferroferric oxide particles can be calculated to be about 20nm by comparing with a standard card, the graphite peak and the magnetic particle peak are detected, and no impurity peak exists, so that the successful preparation of the magnetic graphene material can be proved.

Fig. 2 is a transmission electron micrograph, (a) is a TEM image of a reduced graphene oxide precursor prepared in example one step three, (b) is a TEM image of magnetic graphene with a narrow thin dimension prepared in example one, (c) is a HRTEM image of magnetic graphene with a narrow thin dimension prepared in example one; as can be seen, the width of the magnetic graphene is about 200nm, the aspect ratio is high, and the magnetic graphene has a narrow and thin dimension; the particle size of the magnetic particles is about 15-25 nm, the distribution is good, and the magnetic particles are consistent with the analysis structure shown in the figure 1; under high resolution, the characteristic lattice fringes of ferroferric oxide with the lattice spacing of 0.252nm on the surface of the magnetic graphene can be clearly seen, which indicates that the magnetic particles are well combined.

Fig. 3 is a raman spectrum of magnetic graphene with a narrow and thin dimension prepared in example one; according to the figure, three characteristic peaks appear in the Raman spectrum of the magnetic graphene, the D peak represents a disordered vibration peak of graphite, the G peak is a characteristic peak of the graphene, the 2D peak represents an interlayer stacking mode of carbon atoms, the thickness of the graphene material is determined, and the weaker 2D peak indicates that the multilayer magnetic graphene material is successfully prepared.

Fig. 4 is a hysteresis loop diagram of magnetic graphene with narrow and thin dimensions prepared in the first embodiment; as can be seen from the figure, the prepared magnetic graphene has superparamagnetism, and the magnetic material has good load and good magnetism.

Fig. 5 is a block diagram of electromagnetic wave absorption energy of a wave absorber with different thicknesses tested by a coaxial method after uniformly mixing magnetic graphene with a narrow and thin size and a paraffin wax matrix prepared in the first embodiment, where 1 is the wave absorption performance of the wave absorber with a thickness of 5.0mm, 2 is the wave absorption performance of the wave absorber with a thickness of 4.5mm, 3 is the wave absorption performance of the wave absorber with a thickness of 4.0mm, 4 is the wave absorption performance of the wave absorber with a thickness of 3.5mm, 5 is the wave absorption performance of the wave absorber with a thickness of 3.0mm, 6 is the wave absorption performance of the wave absorber with a thickness of 2.5mm, 7 is the wave absorption performance of the wave absorber with a thickness of 2.0mm, and 8 is the wave absorption performance of the wave absorber with a thickness of 2.25 mm; wherein the mass ratio of the magnetic graphene with narrow and thin dimensions to the paraffin is 1: 1; as can be seen from the figure, in the range of 2 GHz-18 GHz, when the optimal thickness of the wave absorber is 2.25mm, the minimum absorption loss value can reach-66 dB, namely 99% of electromagnetic waves can be absorbed, and the electromagnetic shielding effect can be achieved. The excellent performance is that the prepared magnetic graphene has excellent narrow and thin size and multilayer structure and well-combined magnetic particles, the magnetic graphene has multiple wave absorption mechanisms of magnetic hysteresis loss and dielectric loss, the narrow and thin size magnetic graphene with excellent transverse-longitudinal ratio forms a network structure, the magnetic graphene and the multilayer material are stacked and laminated together to enhance the dissipation capacity of the magnetic graphene to electromagnetic waves, the magnetic hysteresis loss mechanism is introduced into the load of the magnetic particles, and the magnetic graphene material has extremely high application prospect in the preparation of wave absorbers used in the electromagnetic shielding field due to the excellent structures and performances.