Cloud-shaped pomelo peel biomass derived carbon broadband absorbing material and preparation method thereof

Abstract

The invention discloses a cloud-shaped pomelo peel biomass derived carbon broadband absorbing material which has an absorption wave range of-40 dB to-60 dB and a wide absorption bandwidth of 6-8 GHz. The invention also discloses a preparation method of the broadband absorbing material. The preparation method comprises the following steps: firstly, selecting waste shaddock peel and preparing cloud-shaped biomass derived carbon through heat treatment; then cobalt nitrate hexahydrate and zinc nitrate hexahydrate are mixed according to a certain mass ratio, hydrothermal treatment is carried out, Co / ZnO is promoted to grow on the surface of biomass-derived carbon in situ, and the biomass-carbon-based microwave absorbing material with broadband absorption bandwidth and excellent impedance matching characteristics is prepared. The method provides a new technical path for the development of the biomass carbon composite microwave absorbing material. The preparation process is simple, environment-friendly and low in cost, has good repeatability and consistency, and is suitable for large-scale production.

Description

Technical Field

[0001] The invention belongs to the technical field of composite material preparation methods, and in particular relates to a cloud-shaped grapefruit peel biomass-derived carbon broadband absorption material, and also relates to a preparation method of the broadband absorption material. Background Art

[0002] With the widespread use of radio communication equipment, electromagnetic wave pollution harms human health and interferes with precision electronic equipment. To address this problem, electromagnetic wave absorbing materials with high absorption capacity, wide absorption bandwidth, thin matching thickness and low cost have become an ideal choice.

[0003] Electromagnetic shielding and absorbing materials, as key materials for protecting humans and precision equipment, not only occupy an important strategic position in the military field, but also have attracted widespread attention in the civilian field.

[0004] Among them, biomass-derived carbon-based composites have gradually become a research hotspot in the field of microwave absorption due to their advantages of being renewable, low-cost, environmentally friendly, and easy to produce. However, the high complex dielectric constant and low complex magnetic permeability of biomass-derived carbon-based composites make their impedance matching poor, affecting their absorption performance, which is still a problem that needs to be solved urgently. Summary of the invention

[0005] The first object of the present invention is to provide a cloud-shaped grapefruit peel biomass-derived carbon broadband absorption material, which solves the problem that the high complex dielectric constant and low complex magnetic permeability of existing biomass-derived carbon-based composite materials lead to poor impedance matching and affect the absorption performance.

[0006] The second object of the present invention is to provide a method for preparing the above broadband absorbing material.

[0007] The first technical solution adopted by the present invention is: cloud-shaped grapefruit peel biomass-derived carbon broadband absorption material, the absorption wave range of the broadband absorption material is -40dB to -60dB, the absorption bandwidth is 6-8 GHz, and the structure is a cloud-shaped lamellar structure.

[0008] The second technical solution adopted by the present invention is: a method for preparing a cloud-shaped grapefruit peel biomass-derived carbon broadband absorption material, which is specifically implemented in the following steps: Step 1: Take the white part of the grapefruit peel, cut it into pieces, wash it, and dry it for later use; Step 2, heat-treating the dried grapefruit peel pieces dried in step 1 to obtain cloud-shaped grapefruit peel biomass-derived carbon powder; Step 3, dissolving cobalt nitrate hexahydrate and zinc nitrate hexahydrate in a certain mass ratio in ethylene glycol and sodium acetate to prepare a mixed aqueous solution 1, that is, obtaining a Co / ZnO mixed aqueous solution; Step 4: adding the cloud-shaped grapefruit peel biomass-derived carbon powder obtained in step 2 to the Co / ZnO mixed aqueous solution in step 3, and obtaining a mixed solution 2 after ultrasonic treatment.

[0009] Step 5: After heating the mixed solution 2 of step 4 for a certain period of time, cooling it to room temperature, finally obtaining a cloud-shaped grapefruit peel biomass-derived carbon broadband absorption material.

[0010] The second technical solution adopted by the present invention is also characterized in that: Preferably, in step 1, the white part of the grapefruit peel is taken and cut into small pieces of 1×2 cm, then immersed in deionized water and ultrasonically cleaned at room temperature to remove impurities and dust.

[0011] Preferably, in step 1, the clean small pieces of grapefruit peel are placed in an oven, the temperature is set to 50-70° C., the holding time is 10-14 hours, and the pieces are dried for later use.

[0012] Preferably, in step 1, the dried grapefruit peel pieces are placed in a tubular furnace under an argon atmosphere for 1-3 hours at a temperature of 600-800° C. to obtain cloud-shaped grapefruit peel biomass-derived carbon powder.

[0013] Preferably, in step 3, the mass ratio of cobalt nitrate hexahydrate to zinc nitrate hexahydrate is 0.3-1.5:1, the volume ratio of ethylene glycol to sodium acetate is 14 mL:1 g, and the volume ratio of ethylene glycol to zinc nitrate hexahydrate is 233 mL:1 g.

[0014] Preferably, in step 3, the mixture is transferred to a 50 mL high temperature resistant reactor for reaction at a temperature of 140-200° C. for a reaction time of 10-14 hours.

[0015] Preferably, the ultrasonic treatment in step 4 is performed for 50-70 minutes.

[0016] The beneficial effects of the present invention are: The present invention provides a cloud-shaped grapefruit peel biomass-derived carbon broadband absorbing material and a preparation method thereof, which has the advantage of being more convenient and easy to operate compared to traditional technologies, and the operation steps are concise and easy to control. The method can accurately control the morphology and structure of the material, successfully prepare a cloud-shaped composite absorbing material, which not only significantly expands the effective absorption bandwidth of the absorbing material, but also optimizes the impedance matching performance. The preparation process adopted is stable and reliable, with a high degree of controllability, ensuring that the prepared absorbing material has excellent repeatability and consistency, meeting the needs of large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a scanning electron microscope image of the cloud-shaped grapefruit peel biomass-derived carbon broadband absorption material of the present invention; Figure 2 This is a scanning electron microscope image of the Co / ZnO particle rivets obtained in Example 3 in the cloud-shaped grapefruit peel biomass-derived carbon absorption material; Figure 3 This is a scanning electron microscope image of the Co / ZnO particle rivets obtained in Example 6 in the cloud-shaped grapefruit peel biomass-derived carbon absorption material; Figure 4 3 is an absorption bandwidth efficiency diagram of samples at different mass ratios of cobalt nitrate hexahydrate and zinc nitrate hexahydrate in the embodiment. DETAILED DESCRIPTION

[0018] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings.

[0019] The present invention provides a cloud-shaped grapefruit peel biomass-derived carbon broadband absorption material, the broadband absorption material has an absorption wave range of -40dB to -60dB, an absorption bandwidth of 6-8 GHz, and a cloud-shaped sheet structure, such as Figure 1 As shown, the present invention adopts a carbonization and hydrothermal combination process, which can make Co / ZnO particles grow in situ on the cloud-shaped grapefruit peel biomass-derived carbon sheet. The design of the cloud-shaped structure can effectively extend the propagation path of electromagnetic waves and obtain a broadband absorption bandwidth.

[0020] The Co / ZnO / grapefruit peel biomass-derived carbon absorbing material prepared by the present invention comprises Co / ZnO particles loaded on cloud-shaped grapefruit peel biomass-derived carbon sheets (the product after carbonization of grapefruit peel is grapefruit peel biomass-derived carbon with a cloud-shaped morphology), wherein the cloud-shaped and heterogeneous interfaces between the particles are conducive to promoting the dissipation of electromagnetic waves inside the material, thereby obtaining excellent absorption bandwidth performance of 7.1 GHz and satisfactory microwave absorption performance of -55 dB.

[0021] The microwave absorption performance and absorption bandwidth of the Co / ZnO / grapefruit peel biomass-derived carbon absorbing material prepared by the present invention are mainly derived from the dielectric loss capacity of the grapefruit peel biomass carbon itself and the magnetic loss capacity brought by the Co / ZnO particles riveted on the biomass carbon sheet. By adjusting the proportion of the components, the absorption performance can be flexibly adjusted, so that the material can obtain good impedance matching and improve the dissipation capacity of electromagnetic waves.

[0022] The present invention also provides a method for preparing the broadband absorption material, which specifically comprises the following steps: The cloud-shaped grapefruit peel biomass-derived carbon-based absorber prepared by heat treatment and hydrothermal method has a wide absorption bandwidth (6-8 GHz) and excellent wave absorption performance (-40 dB to -60 dB).

[0023] Step 1, preparing grapefruit peel biomass-derived carbon; Take the white part of the grapefruit peel, cut it into small pieces of 1*2 cm, and then soak it in deionized water and ultrasonically wash it at room temperature to remove impurities and dust. Then, place the cleaned grapefruit peel small pieces in an oven, set the temperature to 50-70°C, keep it dry for 10-14 hours, and wait until it is completely dry. Then, put the dried small pieces into a tube furnace for heat treatment, heat to 600-800°C in an argon atmosphere, and keep it warm for 1-3 hours to obtain cloud-shaped grapefruit peel biomass-derived carbon powder, marked as C.

[0024] In step 1, the volume of deionized water is 1000 mL, the drying temperature of the grapefruit peel pieces is set at 50-70° C., the drying time is 10-14 hours, and the heat treatment is carried out under an argon atmosphere at a temperature range of 600-800° C. for a holding time of 1-3 hours.

[0025] Step 2, preparing a Co / ZnO mixed aqueous solution; Dissolve cobalt nitrate hexahydrate and zinc nitrate hexahydrate in ethylene glycol and sodium acetate in a certain mass ratio to prepare a mixed aqueous solution 1, and stir magnetically at room temperature for 20-40 minutes to obtain a uniform solution; In step 2, the mass ratio of cobalt nitrate hexahydrate to zinc nitrate hexahydrate is 0.3-1.5:1, the volume ratio of ethylene glycol to sodium acetate is 14 mL:1 g, and the volume ratio of ethylene glycol to zinc nitrate hexahydrate is 233 mL:1 g.

[0026] Step 3, preparing cloud-shaped Co / ZnO / C granular biomass-derived carbon absorption material; The cloud-shaped grapefruit peel biomass-derived carbon powder obtained in step 1 is added to the Co / ZnO mixed aqueous solution in step 2 in a certain proportion, and ultrasonically treated for 50-70 minutes to obtain a mixed solution 2. Then, the mixed solution is transferred to a 50 mL high temperature resistant reactor, the reaction temperature is set to 140-200°C, and the reaction time is 10-14 hours. After the reaction is completed and cooled to room temperature, a Co / ZnO / C particle-derived carbon material is finally obtained, that is, Co / ZnO particles are riveted in a cloud-shaped grapefruit peel biomass-derived carbon broadband absorption material; In step 3, the mixture is transferred to a 50 mL high temperature resistant reactor, the reaction temperature is set to 140-200° C., and the reaction time is 10-14 hours.

[0027] The composition of the present invention is further described below by way of examples and drawings.

[0028] Example 1 The white part of the grapefruit peel was taken and cut into small pieces of 1×2 cm, which were then soaked in 1000 mL of deionized water and ultrasonically cleaned twice at room temperature for 10 minutes each time to remove impurities and dust. After cleaning, the grapefruit peel small pieces were placed in an oven with a set temperature of 60°C for 12 hours to dry and obtain clean white small pieces. Then, the dried grapefruit peel small pieces were placed in a vacuum tube furnace and heat treated under an argon atmosphere. The heating rate was set to 2-5°C / min, the temperature was raised to 700°C, and the temperature was maintained for 2 hours to obtain cloud-like grapefruit peel biomass-derived carbon.

[0029] Cobalt nitrate hexahydrate and zinc nitrate were dissolved in 70 mL of ethylene glycol and 5 g of sodium acetate solution at a mass ratio of 1:1, and the volume ratio of ethylene glycol to sodium acetate was 14 mL:1 g, to prepare a mixed aqueous solution 1. The solution was magnetically stirred at room temperature for 30 minutes to obtain a uniform Co / ZnO mixed aqueous solution 1.

[0030] Take 1.0 g of the cloud-shaped grapefruit peel biomass-derived carbon powder prepared in step 1 and add it to the Co / ZnO mixed aqueous solution 1 prepared in step 2. The mixed solution was ultrasonically treated at room temperature for 60 minutes to obtain a mixed solution 2. Subsequently, the mixture was transferred to a 50 mL high temperature resistant reactor, and the reaction temperature was set to 140 ° C for 10 hours. After the reaction was completed, it was naturally cooled to room temperature, and the precipitate was collected to finally obtain a Co / ZnO / C derived carbon material, that is, Co / ZnO particles riveted in a cloud-shaped grapefruit peel biomass-derived carbon broadband absorption material.

[0031] Example 2 The white part of the grapefruit peel was taken and cut into small pieces of 1×2 cm, which were then soaked in 1000 mL of deionized water and ultrasonically cleaned twice at room temperature for 10 minutes each time to remove impurities and dust. After cleaning, the grapefruit peel small pieces were placed in an oven with a set temperature of 50°C for 10 hours to dry and obtain clean white small pieces. Then, the dried grapefruit peel small pieces were placed in a vacuum tube furnace and heat treated under an argon atmosphere. The heating rate was set to 2-5°C / min, the temperature was raised to 600°C, and the temperature was maintained for 1 hour to obtain cloud-like grapefruit peel biomass-derived carbon.

[0032] Cobalt nitrate hexahydrate and zinc nitrate were dissolved in 70 mL of ethylene glycol and 5 g of sodium acetate solution at a mass ratio of 1:1, and the volume ratio of ethylene glycol to sodium acetate was 14 mL:1 g, to prepare a mixed aqueous solution 1. The solution was magnetically stirred at room temperature for 30 minutes to obtain a uniform Co / ZnO mixed aqueous solution 1.

[0033] Take 1.0 g of the cloud-shaped grapefruit peel biomass-derived carbon powder prepared in step 1 and add it to the Co / ZnO mixed aqueous solution 1 prepared in step 2. The mixed solution was ultrasonically treated at room temperature for 50 minutes to obtain a mixed solution 2. Subsequently, the mixture was transferred to a 50 mL high temperature resistant reactor, and the reaction temperature was set to 160 ° C for 12 hours. After the reaction was completed, it was naturally cooled to room temperature, and the precipitate was collected to finally obtain a Co / ZnO / C derived carbon material, that is, Co / ZnO particles riveted in a cloud-shaped grapefruit peel biomass-derived carbon broadband absorption material.

[0034] Example 3 The white part of the grapefruit peel was taken and cut into small pieces of 1×2 cm, which were then soaked in 1000 mL of deionized water and ultrasonically cleaned twice at room temperature for 10 minutes each time to remove impurities and dust. After cleaning, the grapefruit peel small pieces were placed in an oven with a set temperature of 70°C for 14 hours to dry and obtain clean white small pieces. Then, the dried grapefruit peel small pieces were placed in a vacuum tube furnace and heat treated under an argon atmosphere. The heating rate was set to 2-5°C / min, the temperature was raised to 800°C, and the temperature was maintained for 3 hours to obtain cloud-like grapefruit peel biomass-derived carbon.

[0035] Cobalt nitrate hexahydrate and zinc nitrate were dissolved in 70 mL of ethylene glycol and 5 g of sodium acetate solution at a mass ratio of 1:1, and the volume ratio of ethylene glycol to sodium acetate was 14 mL:1 g, to prepare a mixed aqueous solution 1. The solution was magnetically stirred at room temperature for 30 minutes to obtain a uniform Co / ZnO mixed aqueous solution 1.

[0036] Take 1.0 g of the cloud-shaped grapefruit peel biomass-derived carbon powder prepared in step 1 and add it to the Co / ZnO mixed aqueous solution 1 prepared in step 2. The mixed solution was subjected to ultrasonic treatment at room temperature for 70 minutes to obtain a mixed solution 2. Subsequently, the mixture was transferred to a 50 mL high-temperature resistant reactor, and the reaction temperature was set to 180°C for 12 hours. After the reaction was completed, it was naturally cooled to room temperature, and the precipitate was collected to finally obtain a Co / ZnO / C-derived carbon material, that is, Co / ZnO particles riveted in a cloud-shaped grapefruit peel biomass-derived carbon broadband absorption material. According to Figure 1 It can be seen that it can be clearly observed that the composite absorbent prepared with a mass ratio of cobalt nitrate hexahydrate to zinc nitrate hexahydrate of 1:1 in Example 3 has the best morphology, and the grapefruit peel biomass-derived carbon presents a typical cloud-like multilayer structure stacked on each other, and the Co / ZnO particles are uniformly riveted in the cloud-like grapefruit peel biomass-derived carbon sheet.

[0037] The scanning electron microscope image of the Co / ZnO particle rivets obtained in Example 3 on the cloud-shaped grapefruit peel biomass-derived carbon absorber is as follows Figure 2It can be observed that the uniform distribution of Co / ZnO particles on the biomass-derived carbon sheets forms a heterogeneous interface, which enhances the dissipation of electromagnetic wave energy.

[0038] Example 4 The white part of the grapefruit peel was taken and cut into small pieces of 1×2 cm, which were then soaked in 1000 mL of deionized water and ultrasonically cleaned twice at room temperature for 10 minutes each time to remove impurities and dust. After cleaning, the grapefruit peel small pieces were placed in an oven with a set temperature of 60°C for drying to obtain clean white small pieces. Then, the dried grapefruit peel small pieces were placed in a vacuum tube furnace and heat treated under an argon atmosphere. The heating rate was set to 2-5°C / min, the temperature was raised to 700°C, and the temperature was maintained for 2 hours to obtain cloud-like grapefruit peel biomass-derived carbon.

[0039] Cobalt nitrate hexahydrate and zinc nitrate were dissolved in 70 mL of ethylene glycol and 5 g of sodium acetate solution at a mass ratio of 1:1, and the volume ratio of ethylene glycol to sodium acetate was 14 mL:1 g, to prepare a mixed aqueous solution 1. The solution was magnetically stirred at room temperature for 30 minutes to obtain a uniform Co / ZnO mixed aqueous solution 1.

[0040] Take 1.0 g of the cloud-shaped grapefruit peel biomass-derived carbon powder prepared in step 1 and add it to the Co / ZnO mixed aqueous solution 1 prepared in step 2. The mixed solution was placed at room temperature for ultrasonic treatment for 60 minutes to obtain a mixed solution 2. Subsequently, the mixture was transferred to a 50 mL high temperature resistant reactor, the reaction temperature was set to 200 ° C, and maintained for 14 hours. After the reaction was completed, it was naturally cooled to room temperature, and the precipitate was collected to finally obtain a Co / ZnO / C derived carbon material, that is, Co / ZnO particles riveted in a cloud-shaped grapefruit peel biomass-derived carbon broadband absorption material.

[0041] Example 5 The white part of the grapefruit peel was taken and cut into small pieces of 1×2 cm, which were then soaked in 1000 mL of deionized water and ultrasonically cleaned twice at room temperature for 10 minutes each time to remove impurities and dust. After cleaning, the grapefruit peel small pieces were placed in an oven with a set temperature of 60°C for drying to obtain clean white small pieces. Then, the dried grapefruit peel small pieces were placed in a vacuum tube furnace and heat treated under an argon atmosphere. The heating rate was set to 2-5°C / min, the temperature was raised to 700°C, and the temperature was maintained for 2 hours to obtain cloud-like grapefruit peel biomass-derived carbon.

[0042] Cobalt nitrate hexahydrate and zinc nitrate were dissolved in 70 mL of ethylene glycol and 5 g of sodium acetate solution at a mass ratio of 0.3:1, and the volume ratio of ethylene glycol to sodium acetate was 14 mL:1 g, to prepare a mixed aqueous solution 1. The solution was magnetically stirred at room temperature for 30 minutes to obtain a uniform Co / ZnO mixed aqueous solution 1.

[0043] Take 1.0 g of the cloud-shaped grapefruit peel biomass-derived carbon powder prepared in step 1 and add it to the Co / ZnO mixed aqueous solution 1 prepared in step 2. The mixed solution was placed at room temperature for ultrasonic treatment for 60 minutes to obtain a mixed solution 2. Subsequently, the mixture was transferred to a 50 mL high temperature resistant reactor, the reaction temperature was set to 180 ° C, and maintained for 12 hours. After the reaction was completed, it was naturally cooled to room temperature, and the precipitate was collected to finally obtain a Co / ZnO / C derived carbon material, that is, Co / ZnO particles riveted in a cloud-shaped grapefruit peel biomass-derived carbon broadband absorption material.

[0044] Example 6 The white part of the grapefruit peel was taken and cut into small pieces of 1×2 cm, which were then soaked in 1000 mL of deionized water and ultrasonically cleaned twice at room temperature for 10 minutes each time to remove impurities and dust. After cleaning, the grapefruit peel small pieces were placed in an oven with a set temperature of 60°C for drying to obtain clean white small pieces. Then, the dried grapefruit peel small pieces were placed in a vacuum tube furnace and heat treated under an argon atmosphere. The heating rate was set to 2-5°C / min, the temperature was raised to 700°C, and the temperature was maintained for 2 hours to obtain cloud-like grapefruit peel biomass-derived carbon.

[0045] Cobalt nitrate hexahydrate and zinc nitrate were dissolved in 70 mL of ethylene glycol and 5 g of sodium acetate solution at a mass ratio of 1.6:1, and the volume ratio of ethylene glycol to sodium acetate was 14 mL:1 g, to prepare a mixed aqueous solution 1. The solution was magnetically stirred at room temperature for 30 minutes to obtain a uniform Co / ZnO mixed aqueous solution 1.

[0046] Take 1.0 g of the cloud-shaped grapefruit peel biomass-derived carbon powder prepared in step 1 and add it to the Co / ZnO mixed aqueous solution 1 prepared in step 2. The mixed solution was placed at room temperature for ultrasonic treatment for 60 minutes to obtain a mixed solution 2. Subsequently, the mixture was transferred to a 50 mL high temperature resistant reactor, the reaction temperature was set to 180 ° C, and maintained for 12 hours. After the reaction was completed, it was naturally cooled to room temperature, and the precipitate was collected to finally obtain a Co / ZnO / C derived carbon material, that is, Co / ZnO particles riveted in a cloud-shaped grapefruit peel biomass-derived carbon broadband absorption material.

[0047] The scanning electron microscope image of the Co / ZnO particle rivets obtained in Example 6 on the cloud-shaped grapefruit peel biomass derived carbon absorbent material is as follows: Figure 3 shown.

[0048] In Examples 1 to 4 of the present invention, composite absorbent materials were prepared using different experimental environments under the condition that the mass ratio of cobalt nitrate hexahydrate to zinc nitrate hexahydrate was 1:1. Through comparative experiments, the experimental conditions shown in Example 3 were preferably obtained. In Examples 5 and 6, composite absorbent materials were prepared using mixtures of cobalt nitrate hexahydrate to zinc nitrate hexahydrate in different mass ratios, 0.3:1 and 1.6:1, respectively, under the same experimental environment. The experimental results show that by adjusting the mass ratio of the mixture of cobalt nitrate hexahydrate to zinc nitrate hexahydrate, the impedance matching and attenuation constant of the composite absorbent material can be effectively regulated, thereby adjusting its absorption bandwidth and absorption performance.

[0049] According to the present invention, the maximum absorption bandwidth of the prepared Co / ZnO / C composite absorption material is 7.1 GHz, which is 121.9% higher than that of the pure grapefruit peel biomass carbon absorption material. Figure 4 As shown in the figure, when the mass ratio of cobalt nitrate hexahydrate to zinc nitrate hexahydrate is 1:1, the absorption bandwidth of the obtained composite absorber reaches 7.1 GHz, and the microwave absorption performance can reach -55 dB. It can be concluded that the prepared Co / ZnO / C composite absorber has a wide absorption bandwidth and excellent absorption performance.

[0050] In summary, the preparation method of the Co / ZnO particle rivets and cloud-shaped grapefruit peel biomass-derived carbon broadband absorption material provided by the present invention has the advantages of simple process, easy control and low cost; the prepared Co / ZnO / C composite absorption material not only has a broadband absorption bandwidth, but also has excellent wave absorbing performance, which meets the needs of practical applications.

Claims

1. Cloud-shaped grapefruit peel biomass-derived carbon broadband absorption material, characterized in that: The broadband absorption material has an absorption wave range of -40 dB to -60 dB, an absorption bandwidth of 6-8 GHz, and a cloud-like sheet structure.

2. The method for preparing the cloud-shaped grapefruit peel biomass-derived carbon broadband absorption material according to claim 1, characterized in that: Please follow the steps below to implement: Step 1: Take the white part of the grapefruit peel, cut it into pieces, wash it, and dry it for later use; Step 2, heat-treating the dried grapefruit peel pieces dried in step 1 to obtain cloud-shaped grapefruit peel biomass-derived carbon powder; Step 3, dissolving cobalt nitrate hexahydrate and zinc nitrate hexahydrate in a certain mass ratio in ethylene glycol and sodium acetate to prepare a mixed aqueous solution 1, that is, obtaining a Co / ZnO mixed aqueous solution; Step 4, adding the cloud-shaped grapefruit peel biomass-derived carbon powder obtained in step 2 to the Co / ZnO mixed aqueous solution in step 3, and obtaining a mixed solution 2 after ultrasonic treatment; Step 5: After heating the mixed solution 2 of step 4 for a certain period of time, cooling it to room temperature, finally obtaining a cloud-shaped grapefruit peel biomass-derived carbon broadband absorption material.

3. The method for preparing the cloud-shaped grapefruit peel biomass-derived carbon broadband absorption material according to claim 2, characterized in that: In step 1, the white part of the grapefruit peel is taken and cut into small pieces of 1×2 cm, then immersed in deionized water and ultrasonically cleaned at room temperature to remove impurities and dust.

4. The method for preparing the cloud-shaped grapefruit peel biomass-derived carbon broadband absorption material according to claim 2, characterized in that: In the step 1, a clean piece of grapefruit peel is placed in an oven, the temperature is set to 50-70° C., the holding time is 10-14 hours, and the dried piece is set aside.

5. The method for preparing the cloud-shaped grapefruit peel biomass-derived carbon broadband absorption material according to claim 2, characterized in that: In the step 1, the dried grapefruit peel pieces are placed in a tubular furnace under an argon atmosphere for 1-3 hours at a temperature of 600-800° C. to obtain cloud-shaped grapefruit peel biomass-derived carbon powder.

6. The method for preparing the cloud-shaped grapefruit peel biomass-derived carbon broadband absorption material according to claim 2, characterized in that: In the step 3, the mass ratio of cobalt nitrate hexahydrate to zinc nitrate hexahydrate is 0.3-1.5:1, the volume ratio of ethylene glycol to sodium acetate is 14 mL:1 g, and the volume ratio of ethylene glycol to zinc nitrate hexahydrate is 233 mL:1 g.

7. The method for preparing the cloud-shaped grapefruit peel biomass-derived carbon broadband absorption material according to claim 2, characterized in that: In step 3, the mixture is transferred to a 50 mL high temperature resistant reactor for reaction at a temperature of 140-200° C. for a reaction time of 10-14 hours.

8. The method for preparing the cloud-shaped grapefruit peel biomass-derived carbon broadband absorption material according to claim 2, characterized in that: In step 4, the ultrasonic treatment is performed for 50-70 minutes.

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