Controllable preparation and application of metal single atom / nanocluster co-doped chopped carbon fibers by microwave carbon thermal shock

Abstract

The present invention relates to the technical field of functional carbon fiber composite materials, specifically a microwave carbon thermal shock controllable preparation and application of metal single atom / nanoclusters co-doped chopped carbon fibers, wherein the chopped carbon fibers are dispersed in a cellulose solution and subjected to microwave surface pretreatment, and then blended with a metal salt. The oxygen-containing functional groups on the surface of the pretreated chopped carbon fibers are utilized to effectively anchor metal salt ions, and the blended system is placed in a microwave oven for carbon thermal shock, causing defects to be generated on the surface of the inert carbon fibers while the metal ions are reduced to metal single atoms / nanoclusters. The present invention adopts a green, environmentally friendly and convenient microwave carbon thermal shock process, which can achieve the introduction of defects on the surface of the inert carbon fibers and simultaneous metal reduction doping within a few minutes, effectively solving the problems of inevitable side reactions and the single electromagnetic wave loss mechanism of the carbon fibers in traditional preparation methods.

Description

Technical Field

[0001] The present invention relates to the technical field of functional carbon fiber composite materials, in particular to a microwave carbon thermal shock controllable preparation and application of metal single atom / nano cluster co-doped chopped carbon fibers. Background Art

[0002] Carbon fiber, a fibrous material composed of carbon atoms bonded together by strong chemical bonds, offers numerous advantages, including lightweight, high strength, excellent mechanical properties and toughness, and environmental friendliness. It holds enormous potential for application in aerospace, automotive, and other fields. Furthermore, carbon fiber exhibits excellent dielectric properties, leading researchers to combine it with functional nanoparticles to achieve diverse functions and applications. For example, composite materials formed with ferrites and transition metal nanoparticles have demonstrated significant advantages in areas such as electromagnetic shielding and electromagnetic wave absorption.

[0003] Currently, a variety of methods have been developed for preparing composite materials of metal nanoparticles and chopped carbon fibers, including hydrothermal methods, high-temperature pyrolysis methods, chemical vapor deposition methods, and microwave carbon thermal reduction methods. Among them, microwave carbon thermal reduction can significantly improve surface roughness and increase the specific surface area of ​​the fiber. It can also form functional groups on the carbon fiber surface, enhancing surface activity and wettability, enabling simultaneous fiber surface treatment and metal particle reduction modification, a simple, efficient, and environmentally friendly process. Furthermore, microwave carbon thermal reduction has a short reaction time (within minutes) and effectively suppresses the occurrence of various side reactions. Simply by varying the amount of metal salt precursor, scale-controlled metal single atoms and their clusters can be rapidly obtained, easily meeting the needs of industrial production. However, the preparation of controllable metal atom-doped chopped fiber absorbers using microwave carbon thermal reduction methods is currently rare.

[0004] Introducing metal single atoms and their nanoclusters on the surface of carbon fiber can break the symmetrical carbon hexagonal ring structure, form dipoles, enhance the dielectric polarization effect, and then synergistically improve the absorption performance of the composite material with the intrinsic dielectric effect of carbon fiber. Therefore, it has broad application prospects in the fields of electromagnetic shielding and electromagnetic wave absorption. Summary of the Invention

[0005] In order to solve the problems in the traditional metal atom-doped chopped fiber preparation process where the inertness of the fiber hinders the surface loading of metal particles, and there are inevitable side reactions in the synthesis process, which limit the practical application of the prepared composite materials, the present invention provides a microwave carbon thermal shock controllable preparation and application of metal single atom / nanocluster co-doped chopped carbon fibers.

[0006] The present invention is achieved through the following technical solutions: A microwave carbon thermal shock controllable preparation of metal single atom / nano cluster co-doped chopped carbon fibers comprises the following steps:

[0007] (1) preparing a cellulose solution, then dispersing the chopped carbon fiber powder in the cellulose solution, and ultrasonically dispersing the powder to obtain a chopped carbon fiber dispersion;

[0008] (2) placing the chopped carbon fiber dispersion in a microwave oven for microwave pretreatment to obtain a surface pretreated chopped carbon fiber dispersion;

[0009] (3) preparing a metal salt aqueous solution, and then adding it to the surface pretreated chopped carbon fiber dispersion prepared in step (2), ultrasonically treating it, and utilizing the defects generated by the surface pretreatment of the chopped carbon fibers and the anchoring effect of the active groups of cellulose on the metal ions to uniformly load the metal ions on the surface of the chopped carbon fibers, thereby obtaining a metal salt / chopped carbon fiber mixed system;

[0010] (4) The mixed system obtained in step (3) is placed in a microwave oven for microwave reaction. During this process, the π electron cloud conjugated system of the chopped carbon fiber produces multiple interactions with the microwave field, forming an arc plasma in a limited space, completing the rapid establishment of the local thermal environment of the carbon fiber and causing its surface to be etched by active oxygen-containing functional groups to form surface defects. At the same time, the reduction and doping of metal ions are completed synchronously to obtain metal single atom / nanocluster co-doped chopped carbon fiber.

[0011] As a further improvement of the preparation technology solution of the present invention, the cellulose is selected from any one of methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose, or a mixture of several of them.

[0012] As a further improvement of the preparation technology solution of the present invention, in step (1), the ultrasonic power is 200-400 W, and the ultrasonic dispersion time is 10-20 min.

[0013] As a further improvement of the preparation technology solution of the present invention, in step (1), the mass ratio of the chopped carbon fibers to the cellulose in the chopped carbon fiber dispersion is 2:1.

[0014] As a further improvement of the preparation technology solution of the present invention, in step (1), the concentration of the cellulose solution is 0.5-1.5 wt%.

[0015] As a further improvement of the preparation technology solution of the present invention, in step (2), the power of the microwave surface pretreatment is 500~700 W, and the pretreatment time is 2~4 min.

[0016] As a further improvement of the preparation technology scheme of the present invention, in step (3), the metal salt is a mixture of one or more metal salts of transition metals iron, cobalt, and nickel in any proportion, and the concentration of the metal salt aqueous solution is 0.05~0.1mmol / L; the metal salt aqueous solution is added to the surface pretreated chopped carbon fiber dispersion prepared in step (2) according to a mass ratio of chopped carbon fiber: metal ion of 500~1000:20~40.

[0017] As a further improvement of the preparation technology solution of the present invention, in step (3), the ultrasonic power is 200~400 W, and the ultrasonic time is 10~20 min.

[0018] As a further improvement of the preparation technology solution of the present invention, in step (4), the power of the microwave reaction is 500-700 W, and the reaction time is 3-7 min.

[0019] The present invention also provides the use of the metal single atom / nanocluster co-doped chopped carbon fiber prepared by controllable microwave carbon thermal shock in electromagnetic shielding and electromagnetic wave absorption.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) The present invention avoids the use of multiple types of chemical reducing agents required in conventional preparation processes. Therefore, the preparation process is more environmentally friendly and the product is purer, effectively solving the problems of significantly increased costs and pollution of the production environment.

[0022] (2) The present invention realizes the simultaneous creation of defects on the surface of inert carbon fibers and reduction doping of metals. The process is simple and easy to operate, effectively saving manpower and material resources. Therefore, it is easy to carry out large-scale industrial production.

[0023] (3) The present invention can form atomic-scale electromagnetic energy conversion sites on the surface of carbon fiber, thereby improving the electromagnetic wave absorption performance of carbon fiber, thereby effectively solving the problem of the single wave absorption mechanism of carbon fiber.

[0024] (4) The present invention utilizes the inherent electrical conductivity of carbon fibers and microwave energy to achieve localized rapid heating. The reaction is rapid, requiring only 2 to 6 minutes from the formation of carbon fiber surface defects to the reduction and doping of metal atoms. This effectively resolves the side reaction problems that are unavoidable in traditional preparation methods. Furthermore, by simply controlling the ratio of the metal salt precursor to the chopped carbon fibers, the scale of the metal atom dopant can be effectively controlled. This effectively regulates the ratio of metal single atoms to nanoclusters and the scale of the nanoclusters, thereby effectively controlling the performance of the prepared carbon fiber composite material. Therefore, the application potential is enormous.

[0025] (5) During the preparation process, the active groups of cellulose effectively anchored the metal ions and participated in the microwave carbon reduction process, forming an effective conductive network in the system, further promoting the uniform response of the system to microwave energy. The cellulose almost completely decomposed or participated in the reaction in the high-temperature environment. Therefore, there was no cellulose residue in the obtained metal single atom / nanocluster co-doped chopped carbon fibers. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0028] Figure 1 XRD spectra of Fe-doped chopped carbon fibers and pure chopped carbon fibers prepared in Example 1, Comparative Example 1 and Comparative Example 2.

[0029] Figure 2 The electrical conductivity of the Fe-doped chopped carbon fibers and pure chopped carbon fibers prepared in Example 1, Comparative Example 1 and Comparative Example 2 is shown.

[0030] Figure 3 Electromagnetic wave reflection loss (RL) of Fe-doped chopped carbon fibers and pure chopped carbon fibers prepared in Example 1, Comparative Example 1 and Comparative Example 2.

[0031] Figure 4 The RL is the Fe-doped chopped carbon fiber prepared in Examples 1 to 3 and Comparative Examples 3 to 5. DETAILED DESCRIPTION

[0032] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the solutions of the present invention will be further described below. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein can be combined with each other.

[0033] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present invention, rather than all the embodiments.

[0034] The present invention provides a specific embodiment of the controllable preparation of metal single atom / nanocluster co-doped chopped carbon fibers by microwave carbon thermal shock, comprising the following steps:

[0035] (1) preparing a cellulose solution, then dispersing the chopped carbon fiber powder in the cellulose solution, and ultrasonically dispersing the powder to obtain a chopped carbon fiber dispersion;

[0036] (2) placing the chopped carbon fiber dispersion in a microwave oven for microwave pretreatment to obtain a surface pretreated chopped carbon fiber dispersion;

[0037] (3) preparing a metal salt aqueous solution, and then adding it to the surface pretreated chopped carbon fiber dispersion prepared in step (2), ultrasonically treating it, and utilizing the defects generated by the surface pretreatment of the chopped carbon fibers and the anchoring effect of the active groups of cellulose on the metal ions to uniformly load the metal ions on the surface of the chopped carbon fibers, thereby obtaining a metal salt / chopped carbon fiber mixed system;

[0038] (4) The mixed system obtained in step (3) is placed in a microwave oven for microwave reaction. During this process, the π electron cloud conjugated system of the chopped carbon fiber produces multiple interactions with the microwave field, forming an arc plasma in a limited space, completing the rapid establishment of the local thermal environment of the carbon fiber and causing its surface to be etched by active oxygen-containing functional groups to form surface defects. At the same time, the reduction and doping of metal ions are completed synchronously to obtain metal single atom / nanocluster co-doped chopped carbon fiber.

[0039] In one embodiment provided by the present invention, the cellulose is selected from any one of methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose, or a mixture of several of them.

[0040] In another embodiment provided by the present invention, in step (1), the ultrasonic power is 200-400 W, and the ultrasonic dispersion time is 10-20 min.

[0041] In one embodiment provided by the present invention, in step (1), the mass ratio of the chopped carbon fibers to the cellulose in the chopped carbon fiber dispersion is 2:1.

[0042] In another embodiment provided by the present invention, in step (1), the concentration of the cellulose solution is 0.5-1.5 wt%.

[0043] In one embodiment provided by the present invention, in step (2), the power of the microwave surface pretreatment is 500~700 W, and the pretreatment time is 2~4 min.

[0044] In another embodiment provided by the present invention, in step (3), the metal salt is a mixture of one or more metal salts of transition metals iron, cobalt, and nickel in any proportion, and the concentration of the metal salt aqueous solution is 0.05~0.1 mmol / L; the metal salt aqueous solution is added to the surface pretreated chopped carbon fiber dispersion prepared in step (2) according to a mass ratio of chopped carbon fiber: metal ion of 500~1000:20~40.

[0045] In one embodiment provided by the present invention, in step (3), the ultrasonic power is 200-400 W, and the ultrasonic time is 10-20 min.

[0046] In another embodiment provided by the present invention, in step (4), the power of the microwave reaction is 500-700 W, and the reaction time is 3-7 min.

[0047] In the present invention, the metal single atom / nanocluster co-doped chopped carbon fiber prepared by microwave carbon thermal shock control is used in electromagnetic shielding and electromagnetic wave absorption.

[0048] The specific embodiments of the present invention are described in detail below.

[0049] The performance testing method adopted in the present invention is as follows:

[0050] X-ray diffraction (XRD) was performed using an X-ray diffractometer 2700BX (Haoyuan, China).

[0051] Resistivity: A uniform mixture of 20 wt% sample and 80 wt% paraffin was prepared into a 7.00 mm diameter disc and tested using a four-probe resistivity tester RTS-9 (Four Probes Tech, China).

[0052] Absorption Performance: A coaxial ring with an inner diameter of 3.04 mm and an outer diameter of 7.00 mm was formed from a uniform mixture of 20 wt% sample and 80 wt% paraffin wax. The dielectric constant and permeability of the ring were measured from 2 to 18 GHz using the coaxial reflection / transmission method using a vector network analyzer 3672C (Ceyear, China). Transmission line theory was used to calculate the frequency variation curve (RL-f) of the electromagnetic wave absorption performance in the range of 2 to 18 GHz.

[0053] The specific embodiments of the present invention are described in detail below. Example 1:

[0054] A microwave carbon thermal shock controllable preparation of Fe single atom / nanocluster co-doped chopped carbon fibers comprises the following steps:

[0055] (1) Prepare a 0.5 wt% hydroxyethyl cellulose (HEC) solution, disperse the chopped carbon fiber in the solution at a mass ratio of chopped carbon fiber:HEC = 2:1, and ultrasonicate at 400 W for 10 min to obtain a chopped carbon fiber / HEC dispersion.

[0056] (2) The chopped carbon fiber / HEC dispersion was placed in a microwave oven and surface pretreated at a power of 600 W. After 3 minutes, a surface pretreated chopped carbon fiber / HEC dispersion was obtained.

[0057] (3) Add 40 mg of Fe2(SO4)3 into 1 L of deionized water and dissolve it to obtain a 0.1 mmol / L Fe salt solution. 3+ =1000:40 mass ratio and added it to the surface pretreated chopped carbon fiber / HEC dispersion prepared in step (2), and ultrasonicated at 400 W for 10 min. The defects generated after the surface pretreatment of the chopped carbon fiber and the anchoring effect of the active groups of HEC on Fe ions were utilized to uniformly load the Fe ions on the surface of the chopped carbon fiber to obtain an Fe salt / chopped carbon fiber mixed system.

[0058] (4) The mixed system obtained in step (3) is placed in a microwave oven and subjected to microwave reaction at a power of 700 W for 5 min. During this process, the π electron cloud conjugated system of the chopped carbon fiber produces multiple interactions with the microwave field, forming an arc plasma in a limited space, thereby achieving the rapid establishment of a local thermal environment of the chopped carbon fiber and etching its surface with active oxygen-containing functional groups to form surface defects. At the same time, the Fe ions are simultaneously reduced to Fe single atoms and nanoclusters and co-doped with the chopped carbon fiber to obtain Fe single atom / nanocluster co-doped chopped carbon fiber.

[0059] Comparative Example 1:

[0060] The preparation of Fe single-atom doped chopped carbon fibers by microwave carbon thermal shock is exactly the same as that in Example 1, except that the concentration of the ferric sulfate solution in step (3) is 0.01 mmol / L.

[0061] Comparative Example 2:

[0062] A microwave carbon thermal shock preparation of Fe nanoclusters doped short carbon fibers is exactly the same as that in Example 1, except that the concentration of the ferric sulfate solution in step (3) is 1 mmol / L.

[0063] Example 2:

[0064] The method is exactly the same as Example 1, except that the concentration of the HEC solution in step (1) is 1 wt %, thereby obtaining Fe single atom / nanocluster co-doped chopped carbon fibers.

[0065] Example 3:

[0066] The same method as Example 1 was used, except that the microwave reaction time in step (4) was 7 min, to obtain Fe single atom / nanocluster co-doped chopped carbon fibers.

[0067] Comparative Example 3:

[0068] The same as Example 1, except that the surface pretreatment process in step (2) is omitted.

[0069] Comparative Example 4:

[0070] The same as Example 1, except that the microwave power of the surface pretreatment process in step (2) is 400W.

[0071] Comparative Example 5:

[0072] The same as Example 1, except that the microwave treatment time of the surface pretreatment process in step (2) is 6 min.

[0073] Figure 1 The XRD spectra of Fe-doped chopped carbon fibers and pure chopped carbon fibers prepared in Example 1, Comparative Example 1, and Comparative Example 2 are shown. According to the PDF card, the two characteristic peaks at 25.1° and 43.3° correspond to the (002) and (100) crystal planes of carbon, respectively. In addition to the diffraction peak of carbon, no Fe crystal phase diffraction peaks were detected in Example 1, Comparative Example 1, and Comparative Example 2, indicating that the Fe species in these materials all have small sizes (less than 2 nm), which is below the detectable range of conventional XRD. Example 1 obtained Fe single atom / nanocluster co-doped chopped carbon fibers, which also had the best performance. In Comparative Example 1, a low amount of iron salt was added to obtain metal single atom-doped chopped carbon fibers. In Comparative Example 2, the amount of Fe salt added reached 1 mmol / L, and the high amount of iron salt added resulted in the formation of a complex with nanoclusters (CAs) as doping units on the surface of the chopped carbon fibers. Therefore, it is shown that by precisely controlling the amount of iron salt added (i.e., the mass ratio of iron salt to chopped carbon fibers), the controllable preparation of chopped carbon fibers doped with metal atoms of different sizes can be successfully achieved. Furthermore, during the material preparation process, the active groups of HEC effectively anchored metal ions, participated in the microwave carbon reduction process, and formed an effective conductive network in the system, further promoting the uniform and rapid response of the system to microwave energy. However, the XRD analysis of the sample showed no characteristic peak indicating HEC (~18.97°), indicating that the HEC completely decomposed or participated in the reaction in the high-temperature environment. Therefore, there is no HEC residue in the obtained Fe-doped chopped carbon fibers.

[0074] Depend on Figure 2It can be seen that compared with pure chopped carbon fibers, the electrical conductivity of the metal-doped chopped carbon fiber composite materials prepared in Example 1, Comparative Example 1 and Comparative Example 2 is significantly reduced. This is attributed to the surface defects formed by etching of the carbon fiber surface by active oxygen-containing functional groups during the microwave reaction, the point defects on the carbon fiber surface caused by Fe doping, and the redistribution of surface charge. These are not only beneficial to the improvement of the polarization loss electromagnetic wave performance, but also can effectively solve the problem of poor interface impedance matching performance caused by the high electrical conductivity of carbon fibers.

[0075] Depend on Figure 3 It can be seen that the maximum effective absorption bandwidth of the Fe single atom / nanocluster co-doped chopped carbon fibers prepared in Example 1 reaches 6.36 GHz, which is significantly improved compared with the 4.64 GHz of the Fe single atom-doped chopped carbon fibers prepared in Comparative Example 1 with the same filling amount and the 4.52 GHz of the Fe nanocluster-doped chopped carbon fibers prepared in Comparative Example 2. At the same time, the Fe single atom / nanocluster co-doped chopped carbon fibers prepared in Example 1 achieved a minimum reflection loss of -51.46 dB, which is also significantly better than that of Comparative Examples 1 and 2. The reason is that: Fe single atoms and Fe nanoclusters, as multi-scale dipoles, form more diverse dipole polarization relaxation paths inside the material, which significantly enhances the polarization loss electromagnetic wave capability. Therefore, the absorption performance of the Fe single atom / nanocluster co-doped chopped carbon fibers is significantly improved. This is due to the improvement of the traditional preparation process of the present invention, which not only effectively improves the inertness of the carbon fiber surface, but also realizes the fine control of the metal atom doping scale, thereby effectively solving the problem of the single electromagnetic wave loss mechanism of the carbon fiber.

[0076] Depend on Figure 4 As can be seen, Examples 1, 2, and 3 achieved minimum reflection losses of -51.46 dB, -45.67 dB, and -46.01 dB, respectively, within the 2-18 GHz range, significantly outperforming Comparative Examples 3, 4, and 5. Furthermore, Example 1 achieved a maximum effective absorption bandwidth of 6.36 GHz, surpassing Comparative Examples 3 (3.40 GHz), 4 (3.20 GHz), and 5 (5.14 GHz). This demonstrates the importance of surface pretreatment in obtaining excellent-performance Fe single-atom / nanocluster co-doped chopped carbon fibers using the present method.

[0077] The above description is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Although detailed descriptions have been made with reference to the aforementioned embodiments, those skilled in the art should understand that they may still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents; and such modifications or replacements do not deviate from the essence of the corresponding technical solutions within the scope of the technical solutions of the embodiments, and they should all be included in the scope of protection of the claims.

Claims

1. A microwave carbon thermal shock controllable preparation of metal single atom / nanocluster co-doped chopped carbon fibers, characterized in that: The following steps are involved: (1) preparing a cellulose solution, then dispersing the chopped carbon fiber powder in the cellulose solution, and ultrasonically dispersing the powder to obtain a chopped carbon fiber dispersion; (2) placing the chopped carbon fiber dispersion in a microwave oven for microwave pretreatment to obtain a surface pretreated chopped carbon fiber dispersion; (3) preparing a metal salt aqueous solution, and then adding it to the surface pretreated chopped carbon fiber dispersion prepared in step (2), ultrasonically treating it, and utilizing the defects generated by the surface pretreatment of the chopped carbon fibers and the anchoring effect of the active groups of cellulose on the metal ions to uniformly load the metal ions on the surface of the chopped carbon fibers, thereby obtaining a metal salt / chopped carbon fiber mixed system; in step (3), the metal salt is a mixture of one or more metal salts of transition metals such as iron, cobalt, and nickel in any proportion, and the concentration of the metal salt aqueous solution is 0.05-0.1 mmol / L; adding the metal salt aqueous solution to the surface pretreated chopped carbon fiber dispersion prepared in step (2) according to a mass ratio of chopped carbon fibers to metal ions of 500-1000:20-40; (4) The mixed system obtained in step (3) is placed in a microwave oven for microwave reaction. During this process, the π electron cloud conjugated system of the chopped carbon fiber produces multiple interactions with the microwave field, forming an arc plasma in a limited space, completing the rapid establishment of the local thermal environment of the carbon fiber and causing its surface to be etched by active oxygen-containing functional groups to form surface defects. At the same time, the reduction and doping of metal ions are completed synchronously to obtain metal single atom / nanocluster co-doped chopped carbon fiber.

2. The microwave carbon thermal shock controllable preparation of metal single atom / nanocluster co-doped chopped carbon fibers according to claim 1, characterized in that: The cellulose is selected from any one of methyl cellulose, hydroxyethyl cellulose and hydroxypropyl cellulose or a mixture of several thereof.

3. The microwave carbon thermal shock controllable preparation of metal single atom / nanocluster co-doped chopped carbon fibers according to claim 1, characterized in that: In step (1), the ultrasonic power is 200-400 W, and the ultrasonic dispersion time is 10-20 min.

4. The microwave carbon thermal shock controllable preparation of metal single atom / nanocluster co-doped chopped carbon fibers according to claim 1, characterized in that: In step (1), the mass ratio of the chopped carbon fibers to the cellulose in the chopped carbon fiber dispersion is 2:

1.

5. The microwave carbon thermal shock controllable preparation of metal single atom / nanocluster co-doped chopped carbon fibers according to claim 1, characterized in that: In step (1), the concentration of the cellulose solution is 0.5-1.5 wt%.

6. The microwave carbon thermal shock controllable preparation of metal single atom / nanocluster co-doped chopped carbon fibers according to claim 1, characterized in that: In step (2), the power of the microwave surface pretreatment is 500-700 W, and the pretreatment time is 2-4 min.

7. The microwave carbon thermal shock controllable preparation of metal single atom / nanocluster co-doped chopped carbon fibers according to claim 1, characterized in that: In step (3), the ultrasonic power is 200-400 W, and the ultrasonic time is 10-20 min.

8. The microwave carbon thermal shock controllable preparation of metal single atom / nanocluster co-doped chopped carbon fibers according to claim 1, characterized in that: In step (4), the power of the microwave reaction is 500-700 W, and the reaction time is 3-7 min.

9. Application of the metal single atom / nanocluster co-doped chopped carbon fiber prepared by microwave carbon thermal shock control according to any one of claims 1 to 8 in electromagnetic shielding and electromagnetic wave absorption.

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