阅读说明：本技术 一种核壳异质结构磁性纳米线及其制备方法与应用 (Magnetic nanowire with core-shell heterostructure and preparation method and application thereof ) 是由 杨平安 屈正微 李锐 黄宇轩 黄鑫 寿梦杰 吴德成 周志浩 于 2021-07-14 设计创作，主要内容包括：本发明公开的是一种核壳异质结构磁性纳米线及其制备方法与应用,属于纳米线材料技术领域。核壳异质结构磁性纳米线中以铁纳米线为核、银为壳,采用磁场辅助诱导液相还原法,结合层-岛生长模式制备,具有优良的导电性、抗氧化性耐腐蚀性和吸波性能。核壳异质结构磁性纳米线中铁磁性纳米线中Fe和Ag的摩尔比为1:0.3-1.1,最小反射损耗达到-58.69dB,小于等于-10dB反射率的有效吸收带宽5.78-13.10GHz。本发明具有条件温和、设备简单、重复性好、周期短、可规模化生产等优点,在微波吸收、电催化、柔性透明导电薄膜、表面增强拉曼光谱等方面有广泛的应用前景。(The invention discloses a magnetic nanowire with a core-shell heterostructure, and a preparation method and application thereof, and belongs to the technical field of nanowire materials. The magnetic nano-wire with the nuclear-shell heterostructure is prepared by taking the iron nano-wire as a core and silver as a shell and adopting a magnetic field assisted induced liquid phase reduction method and a bonding layer-island growth mode, and has excellent conductivity, oxidation resistance, corrosion resistance and wave absorption performance. The molar ratio of Fe to Ag in the ferromagnetic nanowires in the core-shell heterostructure magnetic nanowires is 1:0.3-1.1, the minimum reflection loss reaches-58.69 dB, and the effective absorption bandwidth is 5.78-13.10GHz less than or equal to-10 dB reflectivity. The method has the advantages of mild conditions, simple equipment, good repeatability, short period, large-scale production and the like, and has wide application prospects in the aspects of microwave absorption, electrocatalysis, flexible transparent conductive films, surface enhanced Raman spectroscopy and the like.)

1. A magnetic nanowire with a core-shell heterostructure is characterized in that a ferromagnetic nanowire is used as a core and silver is used as a shell in the magnetic nanowire with the core-shell heterostructure; wherein the molar ratio of Fe to Ag in the ferromagnetic nanowires is 1: 0.3-1.1; the magnetic nanowire with the core-shell heterostructure has the diameter of 80-140nm, the length of 5-30um and the length-diameter ratio of 35-375.

2. The preparation method of the core-shell heterostructure magnetic nanowire of claim 1, wherein the method is a liquid phase reduction method bonding layer-island growth mode, and specifically comprises the following steps:

adding ferromagnetic nanowires into deionized water, ultrasonically dispersing the ferromagnetic nanowires uniformly, adding a dispersing agent into an aqueous solution of the ferromagnetic nanowires for dispersing, applying a parallel magnetic field, continuously adding a silver nitrate solution with the concentration of 5.4-23.1mmol/L, stirring to uniformly mix, adding a reducing agent solution with the concentration of 1.6-2.4mol/L, reacting for 20-35min, standing for 5-10min, centrifuging, cleaning, and collecting by using a neodymium iron boron magnet to obtain the magnetic nanowires with the core-shell heterostructure.

3. The method according to claim 2, wherein in the aqueous solution of ferromagnetic nanowires, the concentration of ferromagnetic nanowires is 18 to 21mmol/L, and the concentration of dispersant is 2 to 5 g/L; the volume mass ratio of the ferromagnetic nanowire aqueous solution to the dispersant to the reducing agent is 1:2-5:1, and the volume mass ratio of L to the dispersant to the reducing agent is L to g to L.

4. The method according to claim 3, wherein the dispersant comprises any one or more of polyvinylpyrrolidone, glycerol, edetate, sodium aminotriacetate, sodium pyrophosphate, sodium ethylene diamine tetra methylene phosphate, potassium pyrophosphate, diethylenetriamine pentacarboxylate or ammonium chloride.

5. The method according to claim 3, wherein the reducing agent in the reducing agent solution is any one or more of hydrazine hydrate, hydrazine sulfate, formaldehyde or dimethyl ammonia borane.

6. The use of the core-shell heterostructure magnetic nanowires of claim 1 for microwave absorption, shielding, electrocatalysis, automotive exhaust purification, flexible transparent conductive films, very large scale integrated circuits, and surface enhanced raman spectroscopy.

7. The application of claim 6, wherein the application is the application of core-shell heterostructure magnetic nanowires in the preparation of microwave-absorbing coaxial rings.

8. The use according to claim 7, wherein the coaxial rings are made of core-shell heterostructure magnetic nanowires and paraffin wax in a mass ratio of 1: 4.

Technical Field

The invention relates to the technical field of nanowire materials, in particular to a magnetic nanowire with a core-shell heterostructure and a preparation method and application thereof.

Background

A ferromagnetic nanowire is a stack of nanomaterials in which nanoscale iron atoms are grown in a stack in a certain direction. The nanometer level size and the unique structure enable the ferromagnetic nanowires to show unique physical effects which many bulk phase materials do not have, mainly including small size effect, surface interface effect, quantum size effect and the like. In the existing preparation method of the nanowire, a vapor deposition method, a template synthesis method, an in-situ reduction method and the like are adopted. The existing preparation method relates to the synthesis of ferromagnetic nanowires with stable appearance and uniform structure. The price of iron is low, and meanwhile, the monodisperse ferromagnetic nanowire has good electric conduction, heat conduction and mechanical properties and outstanding electromagnetic properties. However, the ferromagnetic nanowire metal material has very active chemical properties and is easily oxidized under natural conditions, so that the original electromagnetic absorption performance of the material is damaged. Chinese patent document (CN201810949570.3) discloses a preparation method of a bimetal cobalt-based core-shell material, which adopts an in-situ metal replacement method to prepare a composite bimetal cobalt-based shell material taking Co as a core and Ag or Cu as a shell. The preparation of the material has the defects of high-temperature energy consumption, strict requirements on equipment, harsh conditions, poor microwave absorption performance, easy oxidation and the like, so that the development of a simple composite material with excellent wave-absorbing performance becomes a new direction for research of researchers.

In order to overcome the problems of the method, the magnetic nano-wire material with the core-shell heterostructure is prepared by adopting a magnetic field assisted induction liquid phase reduction method, and the structure of the magnetic nano-wire with the core-shell heterostructure can be regulated and controlled by parameters such as reaction time, molar ratio of ferromagnetic nano-wire to metal silver salt and the like. The preparation process of the method is simple and easy to implement, the used raw materials are all cheap common raw materials, and the preparation cost is low. The prepared magnetic nanowire with the core-shell heterostructure has excellent oxidation resistance, corrosion resistance and wave absorbing performance, and has wide application prospect in the fields of microwave absorption and shielding, electrocatalysis, automobile exhaust purification, flexible transparent conductive films, ultra-large scale integrated circuits, surface enhanced Raman spectroscopy and the like.

Disclosure of Invention

In view of the above, an object of the present invention is to provide a method for preparing a core-shell heterostructure magnetic nanowire; the second purpose of the invention is to provide a magnetic nanowire with a core-shell heterostructure; the invention also aims to provide application of the core-shell heterostructure magnetic nanowire in preparation of coaxial ring microwave absorption.

In order to achieve the purpose, the invention provides the following technical scheme:

1. a magnetic nanowire with a core-shell heterostructure is characterized in that a ferromagnetic nanowire is used as a core, and silver is used as a shell; wherein the molar ratio of Fe to Ag in the ferromagnetic nanowires is 1: 0.3-1.1; the diameter of the magnetic nanowire with the core-shell heterostructure is 80-140nm, the length of the magnetic nanowire is 5-30um, and the length-diameter ratio of the magnetic nanowire is 35-375.

2. The preparation method of the magnetic nanowire with the core-shell heterostructure is a liquid phase reduction method bonding layer-island growth mode and specifically comprises the following steps:

adding ferromagnetic nanowires into deionized water, ultrasonically dispersing the ferromagnetic nanowires uniformly, adding a dispersing agent into an aqueous solution of the ferromagnetic nanowires for dispersing, applying a parallel magnetic field, continuously adding 6-22mmol/L silver nitrate solution, stirring to uniformly mix, adding 1.6-2.4mol/L reducing agent, reacting for 20-35min, standing for 5-10min, centrifuging, cleaning, and collecting by using a neodymium iron boron magnet to obtain the magnetic nanowires with the core-shell heterostructure.

Preferably, in the ferromagnetic nanowire aqueous solution, the concentration of the ferromagnetic nanowires is 18-21mmol/L, and the solubility of the dispersing agent is 2-5 g/L; the volume mass ratio of the ferromagnetic nanowire aqueous solution to the dispersant to the reducing agent is 1:2-5:1, and the volume mass ratio of L to the dispersant to the reducing agent is L to g to L.

Preferably, the dispersing agent comprises one or more of polyvinylpyrrolidone, glycerol, ethylene diamine tetraacetic acid salt, sodium aminotriacetate, sodium pyrophosphate, ethylene diamine tetramethylene sodium phosphate, potassium pyrophosphate, diethylenetriamine pentacarboxylate or ammonium chloride.

Preferably, the reducing agent is any one or more of hydrazine hydrate, hydrazine sulfate, formaldehyde or dimethyl ammonia borane.

3. The magnetic nanowire with the core-shell heterostructure is applied to microwave absorption and shielding, electrocatalysis, automobile exhaust purification, flexible transparent conductive films, ultra-large scale integrated circuits and surface enhanced Raman spectroscopy.

Preferably, the application is the application of the magnetic nanowire with the core-shell heterostructure in the preparation of coaxial ring microwave absorption.

Preferably, the coaxial ring is made of core-shell heterostructure magnetic nanowires with a mass ratio of 1:4 and paraffin.

The invention has the beneficial effects that: the invention provides a magnetic nanowire with a core-shell heterostructure and a preparation method and application thereof, wherein the reaction mechanism is that silver ions form silver anchors on the surface of the ferromagnetic nanowire through displacement reaction, and then a large amount of silver is precipitated in reduction reaction and gathered around the ferromagnetic nanowire to form a shell layer, which is a layer-island growth mode. The method has the advantages of normal temperature and pressure reaction, controllable process, cheap and common raw materials and low preparation cost. Due to the defects of easy oxidation and the like of the ferromagnetic nanowires, the oxidation resistance and the corrosion resistance of the ferromagnetic nanowires can be improved after the magnetic nanowires with the core-shell heterostructure are used. Meanwhile, the silver is coated on the surface of the ferromagnetic nanowire to form a core-shell heterostructure, the electromagnetic wave absorbing effect of the ferromagnetic nanowire is improved, the effective bandwidth of the single ferromagnetic nanowire with the reflectivity of less than or equal to-10 dB is lower than 4GHz, the minimum reflection loss is less than-20 dB, the effective bandwidth range of the ferromagnetic nanowire with the reflectivity of less than or equal to-10 dB is 5.78-13.10GHz, and the minimum reflection loss is-58.69 dB. In addition, the magnetic nanowire with the core-shell heterostructure has excellent conductivity, has the characteristics of wide frequency band and high absorption efficiency, has excellent comprehensive wave absorption performance, and has wide application prospect in the fields of flexible sensors, microwave absorption, surface enhanced Raman spectroscopy, electromagnetic shielding, aerospace and the like.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the means of the instrumentalities and combinations particularly pointed out hereinafter.

Drawings

For the purposes of promoting a better understanding of the objects, aspects and advantages of the invention, reference will now be made to the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a flow chart of the preparation of core-shell heterostructure magnetic nanowires in example 1;

FIG. 2 is XRD patterns of core-shell heterostructure magnetic nanowires of examples 1-3 and ferromagnetic nanowires of example 1;

FIG. 3 is an SEM image of core-shell heterostructure magnetic nanowires of example 1;

FIG. 4 is an SEM image of core-shell heterostructure magnetic nanowires of example 2;

FIG. 5 is an SEM image of core-shell heterostructure magnetic nanowires of example 3;

FIG. 6 is a TEM image of core-shell heterostructure magnetic nanowires in example 1;

FIG. 7 is a TEM image of core-shell heterostructure magnetic nanowires in example 2;

FIG. 8 is a TEM image of core-shell heterostructure magnetic nanowires in example 3;

FIG. 9 is a three-dimensional plot of the reflection loss of core-shell heterostructure magnetic nanowires in example 1;

FIG. 10 is a 2D contour plot of the reflection loss of core-shell heterostructure magnetic nanowires of example 1;

FIG. 11 is a three-dimensional plot of the reflection loss of core-shell heterostructure magnetic nanowires in example 2;

figure 12 2D contour plot of the reflection loss of core-shell heterostructure magnetic nanowires in example 2;

figure 13 three-dimensional plot of the reflection loss of core-shell heterostructure magnetic nanowires in example 3;

figure 14 2D contour plot of the reflection loss of core-shell heterostructure magnetic nanowires in example 3.

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It should be noted that the drawings provided in the following embodiments are only for illustrating the basic idea of the present invention in a schematic way, and the features in the following embodiments and examples may be combined with each other without conflict.

Example 1

The preparation method of the magnetic nanowire with the core-shell heterostructure is shown in figure 1, and comprises the following steps:

(1) adding ferromagnetic nanowires (FeNWs) into deionized water, preparing 100ml of ferromagnetic nanowire aqueous solution with the concentration of 20mmol/L, carrying out ultrasonic treatment for 10min, adding 0.3g of dispersant polyvinylpyrrolidone (PVP) to prevent agglomeration after uniformly dispersing the ferromagnetic nanowires;

(2) preparing 100ml of silver nitrate solution with the concentration of 20mmol/L, adding equivalent silver nitrate solution and ferromagnetic nanowire aqueous solution, and stirring for 10min to uniformly mix;

(3) adding a magnetic field device above the reaction tank, keeping the magnetic field device parallel to the upper part of the reaction container, then dropwise adding 100ml of hydrazine hydrate with the concentration of 2mol/L, and standing for reaction for 30 min.

(4) And (3) carrying out centrifugal treatment, cleaning with absolute ethyl alcohol, and collecting with a neodymium iron boron magnet to obtain the core-shell heterostructure magnetic nanowire.

Mixing the prepared magnetic nanowire with the core-shell heterostructure with paraffin according to the mass ratio of 1:4, wherein the ratio of the ferromagnetic nanowire in the magnetic nanowire with the shell heterostructure to the Fe and the Ag in the silver is 1:1, putting the mixture into a vacuum drying oven, stirring the mixture uniformly until the paraffin is melted, fully mixing the mixture with the paraffin, pouring the mixture into a cylindrical annular mold with the outer diameter of 7.0mm, the inner diameter of 3.04mm and the thickness of 3.0mm, pressing the sample, cooling the material, collecting the cooled material, and measuring the electromagnetic parameters of the material by using a coaxial method.

Example 2

The preparation method of the magnetic nanowire with the core-shell heterostructure specifically comprises the following steps:

(1) adding ferromagnetic nanowires (FeNWs) into deionized water, preparing 100ml of ferromagnetic nanowire aqueous solution with the concentration of 21mmol/L, carrying out ultrasonic treatment for 10min, uniformly dispersing the ferromagnetic nanowires, and adding 0.15g of glycerol, 0.15g of ethylene diamine tetraacetic acid salt and 0.2g of sodium nitrilotriacetate to prevent agglomeration;

(2) preparing 100ml of silver nitrate solution with the concentration of 23.1mmol/L, adding equivalent silver nitrate solution and ferromagnetic nanowire aqueous solution, and stirring for 10min to uniformly mix;

(3) adding a magnetic field device above the reaction tank, keeping the magnetic field device parallel to the upper part of the reaction container, then dropwise adding 100ml of hydrazine sulfate with the concentration of 2.4mol/L, and standing for reaction for 30 min.

(4) And (3) carrying out centrifugal treatment, cleaning with absolute ethyl alcohol, and collecting with a neodymium iron boron magnet to obtain the core-shell heterostructure magnetic nanowire.

Mixing the prepared magnetic nanowire with the core-shell heterostructure with paraffin according to the mass ratio of 1:4, wherein the ratio of the ferromagnetic nanowire in the magnetic nanowire with the silver to the Fe and the Ag in the magnetic nanowire with the core-shell heterostructure is 1:1.1, putting the mixture into a vacuum drying oven to melt the paraffin, stirring the mixture uniformly to fully mix the material with the paraffin, pouring the mixture into a cylindrical annular mold with the outer diameter of 7.0mm, the inner diameter of 3.04mm and the thickness of 3.0mm to press a sample, collecting the material after cooling, and measuring the electromagnetic parameters of the material by using a coaxial method.

Example 3

The preparation method of the magnetic nanowire with the core-shell heterostructure specifically comprises the following steps:

(1) adding ferromagnetic nanowires (FeNWs) into deionized water to prepare 100ml of ferromagnetic nanowire aqueous solution with the concentration of 18mmol/L, carrying out ultrasonic treatment for 10min to uniformly disperse the ferromagnetic nanowires, and adding 0.1g of sodium pyrophosphate and 0.1g of ethylene diamine tetramethylene sodium phosphate as dispersing agents to prevent agglomeration;

(2) preparing 100ml of silver nitrate solution with the concentration of 5.4mmol/L, adding equivalent silver nitrate solution and ferromagnetic nanowire aqueous solution, and stirring for 10min to uniformly mix;

(3) adding a magnetic field device above the reaction tank, keeping the magnetic field device parallel to the upper part of the reaction container, then dropwise adding 100ml of formaldehyde with the concentration of 1.6mol/L, and standing for reaction for 30 min.

(4) And (3) carrying out centrifugal treatment, cleaning with absolute ethyl alcohol, and collecting with a neodymium iron boron magnet to obtain the core-shell heterostructure magnetic nanowire.

Mixing the prepared magnetic nanowire with the core-shell heterostructure with paraffin according to the mass ratio of 1:4, wherein the ratio of the ferromagnetic nanowire in the magnetic nanowire with the silver to the Fe and the Ag in the magnetic nanowire with the core-shell heterostructure is 1:0.3, putting the mixture into a vacuum drying oven to melt the paraffin, stirring the mixture uniformly to fully mix the material with the paraffin, pouring the mixture into a cylindrical annular mold with the outer diameter of 7.0mm, the inner diameter of 3.04mm and the thickness of 3.0mm to press a sample, collecting the material after cooling, and measuring the electromagnetic parameters of the material by using a coaxial method.

Example 4

The preparation method of the magnetic nanowire with the core-shell heterostructure specifically comprises the following steps:

(1) adding ferromagnetic nanowires (FeNWs) into deionized water to prepare 100ml of ferromagnetic nanowire aqueous solution with the concentration of 19mmol/L, carrying out ultrasonic treatment for 10min to uniformly disperse the ferromagnetic nanowires, and adding 0.15g of potassium pyrophosphate, 0.15g of diethylenetriamine pentacarboxylate and 0.1g of ammonium chloride to prevent agglomeration;

(2) preparing 100ml of silver nitrate solution with the concentration of 14mmol/L, adding equivalent silver nitrate solution and ferromagnetic nanowire aqueous solution, and stirring for 10min to uniformly mix;

(3) adding a magnetic field device above the reaction tank, keeping the magnetic field device parallel to the upper part of the reaction vessel, then dropwise adding 100ml of 2.2mol/L dimethylaminoborane, and standing for reaction for 30 min.

(4) And (3) carrying out centrifugal treatment, cleaning with absolute ethyl alcohol, and collecting with a neodymium iron boron magnet to obtain the core-shell heterostructure magnetic nanowire.

FIG. 1 is a flow chart of the preparation of core-shell heterostructure magnetic nanowires in example 1.

Fig. 2 is XRD charts of the core-shell heterostructure magnetic nanowires of examples 1 to 3 and the ferromagnetic nanowires of example 1, and it can be seen from fig. 2 that diffraction peaks of the original ferromagnetic nanowires are located at about 38.1 °,44.3 °,64.4 °,77.5 ° and 81.5 ° with respect to (110), (200) and (211)) planes of body-centered cubic α -Fe. Meanwhile, peaks of diffraction at about 2 θ ═ 38.1 °,44.3 °,64.4 °,77.5 ° and 81.5 ° coincide with the (111), (200), (220), (311) and (222) crystal planes of face-centered cubic silver, indicating that the surface of the iron nanowire was successfully coated with silver particles.

Fig. 3 is an SEM image of the magnetic nanowire with core-shell heterostructure in example 1, and it can be seen from fig. 3 that the iron nanowire is coated with a shell, the number of silver shells is relatively large, and the distribution of the silver shell material is not uniform.

Fig. 4 is an SEM image of the magnetic nanowire with the core-shell heterostructure in example 2, and it can be seen from fig. 4 that the iron nanowire surface is coated with a layer of shell, the coating effect is better, the distribution is uniform, and a distinct linear structure can be seen.

Fig. 5 is an SEM image of the magnetic nanowire with the core-shell heterostructure in example 3, and it can be seen from fig. 5 that the iron nanowire surface is coated with a shell, the coating effect is worse than that of example 2, and the silver of the outer layer is not coated well on the iron nanowire surface.

Fig. 6 is a TEM image of the magnetic nanowire with core-shell heterostructure in example 1, and it can be seen from fig. 6 that the silver shell coated on the surface of the iron nanowire has uneven thickness distribution and thicker silver shell, and the product is a monodispersed magnetic nanowire with core-shell heterostructure, and the diameter of the nanowire is 80-140 nm.

Fig. 7 is a TEM image of the magnetic nanowire with the core-shell heterostructure in example 2, and it can be seen from fig. 7 that the iron nanowire has a more significant effect of the silver shell coated on the surface than in example 1, and the product is a monodispersed magnetic nanowire with the core-shell heterostructure, and the diameter of the nanowire is 80-140 nm.

Fig. 8 is a TEM image of the magnetic nanowire with the core-shell heterostructure in example 3, and it can be seen from fig. 8 that the effect of the silver shell coated on the surface of the iron nanowire is poor compared with example 2, and the distribution of the outer silver shell is not uniform, thus the product is a monodisperse magnetic nanowire with the core-shell heterostructure, and the diameter of the nanowire is 80-140 nm.

FIG. 9 is a three-dimensional graph of the reflection loss of the core-shell heterostructure magnetic nanowires of example 1, from FIG. 9, it can be seen that the minimum reflection loss is-53.8 dB at 9.24 GHz.

Fig. 10 is a 2D contour plot of the reflection loss of the magnetic nanowire with core-shell heterostructure in example 1. as can be seen from fig. 10, the change of the minimum reflection loss with different thicknesses is better at the thickness of 2.6-3mm with the increase of the frequency.

FIG. 11 is a three-dimensional graph of the reflection loss of the core-shell heterostructure magnetic nanowires of example 2, from FIG. 11, it can be seen that the minimum reflection loss is-58.6 dB at 7.53 GHz.

Fig. 12 is a 2D contour diagram of the reflection loss of the magnetic nanowire with a core-shell heterostructure in example 2, and it can be seen from fig. 12 that the change of the minimum reflection loss with different thicknesses is better at the thickness of 2.9-3mm as the frequency is increased.

FIG. 13 is a three-dimensional graph of the reflection loss of the core-shell heterostructure magnetic nanowires of example 3, from FIG. 13, it can be seen that the minimum reflection loss is-69.6 dB at 7.02 GHz.

Fig. 14 is a 2D contour plot of the reflection loss of the core-shell heterostructure magnetic nanowires of example 3, and it can be seen from fig. 14 that the minimum reflection loss variation of different thicknesses is better at a thickness of 3-4mm as the frequency increases.

In summary, the invention provides a magnetic nanowire with a core-shell heterostructure, and a preparation method and application thereof, wherein the reaction mechanism is that silver ions form silver anchors on the surface of the ferromagnetic nanowire through a displacement reaction, and then a large amount of silver is precipitated in a reduction reaction and gathered around the ferromagnetic nanowire to form a shell layer, which is a layer-island growth mode. The method has the advantages of normal temperature and pressure reaction, controllable process, cheap and common raw materials and low preparation cost. Due to the defects of easy oxidation and the like of the ferromagnetic nanowires, the oxidation resistance and the corrosion resistance of the ferromagnetic nanowires can be improved after the magnetic nanowires with the core-shell heterostructure are used. Meanwhile, the silver is coated on the surface of the ferromagnetic nanowire to form a core-shell heterostructure, the electromagnetic wave absorbing effect of the ferromagnetic nanowire is improved, the effective bandwidth of the single ferromagnetic nanowire with the reflectivity of less than or equal to-10 dB is lower than 4GHz, the minimum reflection loss is less than-20 dB, the effective bandwidth range of the ferromagnetic nanowire with the reflectivity of less than or equal to-10 dB is 5.78-13.10GHz, and the minimum reflection loss is-58.69 dB. In addition, the magnetic nanowire with the core-shell heterostructure has excellent conductivity, has the characteristics of wide frequency band and high absorption efficiency, has excellent comprehensive wave absorption performance, and has wide application prospect in the fields of flexible sensors, microwave absorption, surface enhanced Raman spectroscopy, electromagnetic shielding, aerospace and the like.

Finally, the above embodiments are only intended to illustrate the technical solutions of the present invention and not to limit the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions, and all of them should be covered by the claims of the present invention.