CN114804070A - Preparation method of carbon nano hemispherical particles - Google Patents

Abstract

The invention discloses a preparation method of carbon nano hemispherical particles, which comprises the following steps: adding organic silicon into an ethanol solution, and stirring to uniformly disperse the organic silicon to obtain a solution A; preparing an alkaline water solution, and then adding the alkaline water solution into the solution A to obtain a solution B; heating and stirring the solution B for hydrolysis reaction to obtain a solution C; adding resorcinol and formaldehyde into the solution C to perform phenolic condensation reaction to obtain mixed reaction liquid; centrifugally washing and drying the mixed reaction liquid to obtain a solid, and then grinding the solid to obtain an intermediate product D; calcining at high temperature to completely carbonize the surface coating layer of the intermediate product D to obtain an intermediate product E; placing the intermediate product E in etching liquid, stirring and etching, performing suction filtration, and washing to be neutral to obtain an intermediate product F; and drying the intermediate product F, and grinding to obtain the product carbon nano hemispherical particles. The carbon nano-hemispherical particles are uniformly distributed, have regular shapes, have vacuum structures and particle size range of 300-350 nanometers, and are good catalyst carrier materials.

Description

A kind of preparation method of carbon nano hemisphere particle

technical field

The invention relates to the field of catalyst preparation, in particular to a particle method of a carbon nano hemisphere material.

Background technique

With the burning of fossil fuels and the increasing energy demand in the world, the environmental crisis and energy crisis force us to look for new energy sources to replace traditional non-renewable energy sources. One of the effective ways to solve this problem is electrocatalysis. Whether it is the application of new batteries, or the development of new energy sources to reduce carbon emissions, such as water electrolysis and CO ₂ electroreduction, all rely on high-efficiency temperature electrocatalysts. The catalyst carrier is an important part of the supported catalyst. A good catalyst carrier not only supports the catalyst, but also greatly improves the performance of the catalyst itself. For electrocatalysis, the optimization of the support can greatly improve the stability of the catalyst, and can also significantly improve the performance of the catalyst by changing the structure and morphology, improving the mass transfer efficiency, and improving the intrinsic activity. Therefore, the preparation of suitable electrocatalytic supports is crucial.

At present, common electrocatalytic carbon supports include carbon fiber cloth, carbon fiber paper, etc., which have a simple structure and cannot expose more active sites to the catalyst. However, catalyst supports such as foamed nickel and foamed cobalt will inevitably react when loaded, which brings difficulties to the study of the final catalytic mechanism. It is also difficult for other catalyst supports, such as silicon-based supports, to achieve both electrical conductivity and high loading. Therefore, it is of great practical significance to provide an electrocatalyst support that can not only maintain good stability and conductivity, but also improve the catalyst performance by exposing more active sites and improving mass transfer.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a preparation method of carbon nano hemispherical particles; the carbon nano hemispherical powder particles synthesized by the preparation method have uniform distribution, uniform size, neat appearance, vacuum structure, and a particle size range of 300-350 nanometers; The carbon nano-hemisphere has a larger specific surface area while ensuring good electrical conductivity, so that the supported catalyst exposes more active sites, and at the same time, the presence of mesopores promotes mass transfer, which is a good catalyst carrier material.

In order to solve the above-mentioned first technical problem, the present invention adopts the following technical scheme:

A preparation method of carbon nano hemispherical particles, comprising the following steps:

1) adding the organosilicon to the ethanol solution and stirring to make it evenly dispersed to obtain solution A;

2) configure aqueous alkali solution, then add it to solution A to obtain solution B;

3) heating and stirring solution B to carry out hydrolysis reaction, after the solution is transformed into milky white, solution C is obtained; adding resorcinol and formaldehyde to solution C to carry out phenolic condensation reaction, stirring makes the phenolic condensation product evenly coated in solution C to form On the silicon sphere template, the mixed reaction solution was obtained;

4) the mixed reaction solution is centrifugally washed, and the solid obtained after the centrifugal washing is dried in a vacuum drying oven to obtain a reddish-brown or light-brown solid, and then the reddish-brown or light-brown solid is ground to obtain intermediate product D;

5) Under the condition of inert atmosphere, high temperature calcination is adopted in the tube furnace to completely carbonize the surface coating of the intermediate product D to obtain the carbonized intermediate product E;

6) taking out the intermediate product E, placing it in the etching solution with stirring and etching, performing suction filtration and washing to neutrality after the etching to obtain the intermediate product F;

7) After drying the intermediate product F in a vacuum drying oven, grinding to obtain carbon nano hemispherical particles of the product of the present invention.

As a further improvement of the technical solution, in step 1), the organosilicon is selected from one or more of propyl orthosilicate, tetrapropoxysilane, and tetraethyl orthosilicate.

Preferably, in step 1), the amount of the organosilicon is 3-12mL; the amount of anhydrous ethanol is 70-150mL.

As a further improvement of the technical solution, in step 2), the alkali is selected from concentrated ammonia, sodium hydroxide or lysine.

Preferably, in step 2), the concentration of the alkaline aqueous solution is 25-30 wt %, and the dosage is 2-10 mL.

As a further improvement of the technical solution, in step 3), the temperature of the heating and stirring is 25-40° C.; and it is sealed during the reaction.

Preferably, in step 3), the heating and stirring are performed using a water bath; the heating and stirring time is 10-40 minutes.

Preferably, in step 3), the formaldehyde comes from 18wt% formaldehyde solution, which contains 5-8wt% methanol stabilizer, and the amount of the formaldehyde solution is 0.56-1.4mL; the amount of the resorcinol is 0.4 mL -1g.

Preferably, in step 3), the reaction time of the phenolic condensation reaction is 3-24h.

As a further improvement of the technical solution, in step 4), the centrifugal washing refers to ultrasonic washing and centrifugal separation with deionized water and absolute ethanol successively, until the last time the liquid is anhydrous and clear after centrifugation. The rotation speed of the centrifugation is 1000-6000 rpm.

Preferably, in step 4), the vacuum degree in the vacuum drying box is 0.08-0.12MPa.

As a further improvement of the technical solution, in step 5), the inert atmosphere is nitrogen or helium.

Preferably, in step 5), the temperature of the high-temperature calcination is 700-900° C., the heating gradient is 1-10K/min, and the time is 1-2h.

As a further improvement of the technical solution, in step 6), the etching solution is selected from sodium hydroxide solution or hydrofluoric acid solution.

Preferably, in step 6), when the etching solution is a sodium hydroxide solution, its concentration is 3-5M.

Preferably, in step 6), the temperature of the stirring etching is 78-82° C. and the time is 8-24 h.

As a further improvement of the technical solution, in step 7), the vacuum degree in the vacuum drying box is 0.08-0.12MPa.

Preferably, in step 7), the temperature in the vacuum drying box is 40-70°C, and the drying time is 12-24h.

Any range recited herein includes the endpoints and any number between the endpoints and any sub-ranges formed by the endpoints or any number between the endpoints.

Unless otherwise specified, each raw material in the present invention can be obtained through commercial purchase, and the equipment used in the present invention can be performed with conventional equipment in the field or with reference to the prior art in the field.

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

In the present invention, a new type of carbon nano hemispherical particle is synthesized by using a template removal method, which is used as an electrocatalyst carrier. The general synthesis idea is to synthesize silica template by alkaline hydrolysis of organosilicon, and use phenolic reaction to coat the organic layer on it. Then, the organic layer is carbonized by high temperature calcination, and then the silicon dioxide template is etched away, and finally a regular and uniform carbon nano hemisphere is formed. The synthesis effect can be well controlled by changing the conditions during the synthesis. Precisely adjusting the conditions makes the carbon nanospheres collapse and collapse from the middle, which can further increase the loading area of the catalyst. The synthesized carbon nano-hemispherical powder has uniform particle distribution, uniform size, neat morphology and vacuum structure, and the particle size range is 300-350 nanometers. At the same time, the surface of the sphere is covered with mesopores, which can not only provide a high specific surface area for the catalyst, but also have good mass transfer capacity. This method is convenient and simple, and provides a good carrier choice for the study of electrocatalysts.

Description of drawings

The specific embodiments of the present invention will be described in further detail below in conjunction with the accompanying drawings.

Fig. 1 is the BJH pore size distribution curve of the sample obtained in Example 1;

Fig. 2 is the transmission electron microscope picture of the sample obtained in Example 1;

Fig. 3 is the XRD spectrum of the sample obtained in Example 1;

Fig. 4 is the transmission electron microscope picture of the prepared sample of Comparative Example 1;

Fig. 5 is the scanning electron microscope picture of the prepared sample of Comparative Example 2;

Fig. 6 is the transmission electron microscope spectrogram of the prepared sample of Comparative Example 2;

Fig. 7 is the scanning electron microscope spectrogram of the prepared sample of Comparative Example 3;

FIG. 8 is a transmission electron microscope spectrum of the sample prepared in Comparative Example 5. FIG.

Detailed ways

In order to illustrate the present invention more clearly, the present invention will be further described below with reference to the preferred embodiments. Those skilled in the art should understand that the content specifically described below is illustrative rather than restrictive, and should not limit the protection scope of the present invention.

As an aspect of the present invention, a preparation method of carbon nano hemispherical particles of the present invention comprises the following steps:

1) adding the organosilicon to the ethanol solution and stirring to make it evenly dispersed to obtain solution A;

2) configure aqueous alkali solution, then add it to solution A to obtain solution B;

3) heating and stirring solution B to carry out hydrolysis reaction, after the solution is transformed into milky white, solution C is obtained; adding resorcinol and formaldehyde to solution C to carry out phenolic condensation reaction, stirring makes the phenolic condensation product evenly coated in solution C to form On the silicon sphere template, the mixed reaction solution was obtained;

4) the mixed reaction solution is centrifugally washed, and the solid obtained after the centrifugal washing is dried in a vacuum drying oven to obtain a reddish-brown or light-brown solid, and then the reddish-brown or light-brown solid is ground to obtain intermediate product D;

5) Under the condition of inert atmosphere, high temperature calcination is adopted in the tube furnace to completely carbonize the surface coating of the intermediate product D to obtain the carbonized intermediate product E;

6) taking out the intermediate product E, placing it in the etching solution with stirring and etching, performing suction filtration and washing to neutrality after the etching to obtain the intermediate product F;

7) After drying the intermediate product F in a vacuum drying oven, grinding to obtain carbon nano hemispherical particles of the product of the present invention.

As a further improvement of the technical solution, in step 1), the organosilicon is selected from one or more of propyl orthosilicate, tetrapropoxysilane, and tetraethyl orthosilicate. Preferably, the organosilicon is propyl orthosilicate, and using tetraethyl orthosilicate as the silicon source is more conducive to regulation, and increasing the amount of tetraethyl orthosilicate will accelerate the crystallization of silicon dioxide, and the carbon nano hemispheres formed finally The inner diameter is increased.

Preferably, in step 1), the amount of the organosilicon is 3-12mL; the amount of anhydrous ethanol is 70-150mL.

As a further improvement of the technical solution, in step 2), the alkali is selected from concentrated ammonia, sodium hydroxide or lysine.

Preferably, in step 2), the concentration of the alkaline aqueous solution is 25-30 wt %, and the dosage is 2-10 mL.

As a further improvement of the technical solution, in step 3), the temperature of the heating and stirring is 25-40° C.; and sealing is performed during the reaction; sealing is helpful to prevent organic silicon from volatilizing.

Preferably, in step 3), the heating and stirring are performed in a water bath, so that the synthesis process is more controllable; the heating and stirring time is 10-40 minutes. The heating and stirring time will affect the degree of hydrolysis and crystallization of silicic acid, thereby affecting the particle size of the silicon sphere template and subsequent carbon spheres.

Preferably, in step 3), the formaldehyde comes from 18wt% formaldehyde solution, which contains 5-8wt% methanol stabilizer, and the amount of the formaldehyde solution is 0.56-1.4mL; the amount of the resorcinol is 0.4 mL -1g. After adding resorcinol and formaldehyde successively, the color of the solution changed from clear and transparent at first to milky white and then slowly changed to reddish brown and finally to dark brown, so that the condensation reaction was completely and well regulated. The amount of diphenol used can adjust the thickness of the finally formed carbon layer.

Preferably, in step 3), the reaction time of the phenolic condensation reaction is 3-24h.

As a further improvement of the technical solution, in step 4), the centrifugal washing refers to ultrasonic washing and centrifugal separation with deionized water and absolute ethanol successively, until the last time the liquid is anhydrous and clear after centrifugation.

Preferably, in step 4), the vacuum degree in the vacuum drying box is 0.08-0.12MPa.

In some embodiments, in step 5), the inert atmosphere is nitrogen or helium.

In certain embodiments, in step 5), the temperature of the high-temperature calcination is 700-900° C., the heating gradient is 1-10K/min, and the time is 1-2h.

In some embodiments, in step 6), the etching solution is selected from sodium hydroxide solution or hydrofluoric acid solution.

In some embodiments, in step 6), when the etching solution is a sodium hydroxide solution, its concentration is 3-5M.

In some embodiments, in step 6), the temperature of the stirring etching is 78-82° C., and the time is 8-24 h.

In certain embodiments, in step 7), the vacuum degree in the vacuum drying box is 0.08-0.12 MPa.

In some embodiments, in step 7), the temperature in the vacuum drying box is 40-70° C., and the drying time is 12-24 h.

In the present invention, a new type of carbon nano hemisphere is synthesized by using the template removal method for electrocatalyst carrier. The synthesis effect can be well controlled by changing the conditions during the synthesis. Precisely adjusting the conditions makes the carbon nanospheres collapse and collapse from the middle, which can further increase the loading area of the catalyst. The synthesized carbon nano-hemispherical powder has uniform particle distribution, uniform size, neat morphology and vacuum structure, and the particle size range is 300-350 nanometers. At the same time, the surface of the sphere is covered with mesopores, which can not only provide a high specific surface area for the catalyst, but also have good mass transfer capacity. This method is convenient and feasible, and provides a good carrier choice for the study of electrocatalysts.

Example 1

A preparation method of carbon nano-hemisphere material, comprising the following steps:

1) Weigh 70mL of absolute ethanol into the beaker with a measuring cylinder, use a pipette to pipette 3.5mL of tetraethyl orthosilicate into the ethanol solution and put it into the magnetic element to stir until it is completely dispersed and keep stirring for later use;

2) Weigh 3mL of 28wt% concentrated ammonia solution and add it to 10mL of deionized water for ultrasonication until uniform dispersion;

3) The ammonia solution was added to the ethanol solution of tetraethyl orthosilicate, the mixed solution was heated in a water bath and maintained at 40°C and magnetically stirred, and stirred for 20 minutes until the solution was about to turn milky white. When stirring, pay attention to sealing the beaker with parafilm to prevent the volatilization of toxic tetraethyl orthosilicate. The addition of ammonia water and heating and stirring make tetraethyl orthosilicate hydrolyze, and the time of heating and stirring will affect the particle size of the finally formed silica template, which is adjusted according to pH value and silicon source content;

4) Use an electronic balance to weigh 0.8g of resorcinol, use a pipette to measure 1.2mL of formaldehyde solution, add it to the mixed solution for phenolic condensation reaction, and stir for 24h to make it evenly coated on the silicon sphere template; After quinone and formaldehyde, the color of the solution changed from clear and transparent at first to milky white and then slowly to reddish brown and finally to dark brown, indicating that the phenolic condensation of silica was coated on silica after nucleation and crystallization of silica;

5) Transfer the mixed solution to a centrifuge tube and centrifuge at 8000 rpm. After centrifugation and stratification, pour off the upper layer of red transparent liquid, add deionized water for ultrasonication to disperse, and centrifuge again to wash off residual ammonia, etc.; continue to pour out the upper layer liquid and add no Water ethanol, after ultrasonic dispersion, centrifugal washing to remove residual phenol, aldehyde, etc., repeat centrifugal washing with absolute ethanol until the upper liquid is transparent and colorless;

6) Dry the bottom solid after centrifugation in a vacuum drying oven at 70℃ for 12h. The vacuum degree in the oven should be kept below 0.08-0.12MPa, and it will appear reddish-brown or light-brown solid after drying. Use a mortar and pestle to grind it into a uniform brown powder for uniform carbonization;

7) Transfer the powder to the porcelain boat and put it into the tube furnace. The tube furnace is first filled with inert gas for 1-2 hours. If the internal oxygen is not discharged, it may cause carbon oxidation and volatilization. Then, the temperature was raised to 900 degrees Celsius at 5K/min, and calcined at high temperature for 2 hours to completely carbonize the coating layer on the surface of the material, and then cooled to room temperature and taken out for use;

8) Take 30.93g of sodium hydroxide and place it in a beaker, add 250mL of deionized water, and put in a magnet, stir magnetically until it is completely dissolved, and prepare a 3mol/L NaOH solution;

9) Take out the carbonized powder and place it in a NaOH solution for heating and stirring at 80°C. When heating and stirring, pay attention to sealing the beaker with a sealing film, and stir for 24 hours until it is completely etched;

10) Suction filtration of the etched mixed solution. When the suction filtration is completed, continue to add deionized water to carry out suction filtration and washing for several times until it is neutral, and the residual sodium hydroxide is washed away;

11) Dry the sample after suction filtration at 40° C. for 24 hours in a vacuum drying oven, and grind it with a mortar to obtain carbon nano-hemispherical particles.

Figure 1 shows the BJH pore size distribution curve of the product prepared in Example 1. It can be seen that the surface of the carbon hemispherical particles is distributed with micropores and mesopores, and has good mass transfer ability. BET test also shows that it has a large The specific surface area (550-700m ² /g).

Figure 2 shows the transmission electron microscope image of the product obtained in Example 1. After low-power transmission microscope detection, the carbon nano-hemisphere material obtained in this example has a uniform size, about 300-350 nanometers, and has a regular and stable structure.

Figure 3 shows the XRD spectrum of the sample prepared in Example 1. According to the figure, the material is amorphous carbon, indicating that the silicon template has been basically removed; it indicates that the carrier will not affect the performance due to silicon, etc., and can provide The large surface area and excellent mass transfer capacity make it an excellent carrier for electrocatalysts; thus, the applicability of this method is demonstrated.

Example 2

Example 1 was repeated except that propyl orthosilicate (TPOS) was used in step 1).

Example 3

Example 1 was repeated, except that in step 2) sodium hydroxide or lysine was used to adjust the pH.

Example 4

Example 1 was repeated, except that HF was used for etching in step 8). Dissolve 5 mL of hydrofluoric acid in 25 mL of deionized water and prepare the solution in a plastic centrifuge tube. Add 0.5 g of carbonized powder to the prepared solution and add a magnet for magnetic stirring. It should be noted that the centrifuge tube is sealed and placed in the fume hood during stirring, and no heating is required.

Comparative Example 1

Example 1 was repeated, except that the resorcinol in step 4) was changed to 0.4 g, and the formaldehyde solution was changed to 0.56 mL.

As shown in Figure 4, the low-power transmission microscope test shows that the carbon spherical catalyst support obtained by this method undergoes irregular collapse because the outer carbon layer is too thin, and finally it is difficult to support the hemispherical morphology structure.

Comparative Example 2

Example 1 was repeated, and the difference was only in that step 4) the consumption of resorcinol was increased to 1.6 g, and the consumption of formaldehyde solution was 2.4 mL.

It can be seen from the SEM test in Fig. 5 that a good spherical shape is present at this time. Through transmission electron microscopy, as shown in Figure 6, regular and uniform carbon nanospheres were formed, which can also be considered as hollow carbon nanospheres electrocatalyst carriers with excellent morphology and structure. However, at this time, the thickness of the carbon layer is relatively thick, about 50 nm, which limits the catalyst loading to a certain extent.

Comparative Example 3

The comparative example 1 was repeated, except that in step 4), after stirring for 3 h, it was left to stand for centrifugal washing.

It can be seen from the SEM test in Fig. 7 that due to the short stirring time, it is difficult for the organic layer formed by phenolic aldehyde to be uniformly coated. It shows that the optimization of Comparative Example 2 cannot be achieved by reducing the stirring time, and the preferred method is to reduce the amount of phenol and aldehyde.

After testing, the obtained Ag nanoparticles showed different Ag distribution and content when different samples were taken for testing.

Comparative Example 4

Example 1 was repeated, the only difference was that in step 6), the calcination temperature was changed to 70° C., kept for 1 h, and then waited for natural cooling.

The powder calcined under this condition often appears dark green. It can be inferred that the carbon spheres under this condition have not been fully carbonized, which brings uncontrollable variables to the catalyst loading in the later stage.

Comparative Example 5

Example 1 was repeated, except that, in step 10), the concentration of the NaOH solution was reduced or the heating and stirring were stopped.

Detected by the low-power transmission microscope in FIG. 8 , the obtained nanoparticles are solid spherical. It can be inferred that the silicon dioxide template inside the carbon spheres under these conditions is not completely etched, the carbon spheres cannot be broken to form a hemispherical shape, and the presence of silicon also greatly affects the performance of the carbon spheres.

Comparative Example 6

Steps 1-5 in Example 1 were repeated, except that, in step 4), without adding resorcinol and formaldehyde solution, the solution was directly stirred for 24h and then centrifuged and washed.

During stirring for 24h, the solution turned milky white and did not change color, indicating that the process of the solution slowly changing from milky white to reddish brown and finally to dark brown was indeed a process of phenolic condensation coating. The solution was centrifuged, washed and dried to obtain a white powder product. After testing, the final product was pure silica particles, indicating that the carbon layer could not be formed without phenolic condensation coating.

To sum up, the preparation method of a carbon nano hemisphere material of the present invention, the selection of template silicon source, the amount of phenolic condensation, the vacuum conditions, the etching conditions, the temperature and time during calcination and carbonization, etc., are coordinated and mutually compatible. Only when a complete technical solution is formed, the carbon nano-hemisphere material catalyst required by the present invention can be prepared.

Obviously, the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those of ordinary skill in the art, changes or modifications in other different forms can also be made on the basis of the above description. Not all implementations can be exhaustive here. Any obvious changes or changes derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims (9)

1. a preparation method of carbon nano hemispherical particle, is characterized in that, comprises the steps: 1) adding the organosilicon to the ethanol solution and stirring to make it evenly dispersed to obtain solution A; 2) configure aqueous alkali solution, then add it to solution A to obtain solution B; 3) heating and stirring solution B to carry out hydrolysis reaction, after the solution is transformed into milky white, solution C is obtained; adding resorcinol and formaldehyde to solution C to carry out phenolic condensation reaction, stirring makes the phenolic condensation product evenly coated in solution C to form On the silicon sphere template, the mixed reaction solution was obtained; 4) the mixed reaction solution is centrifugally washed, and the solid obtained after the centrifugal washing is dried in a vacuum drying oven to obtain a reddish-brown or light-brown solid, and then the reddish-brown or light-brown solid is ground to obtain intermediate product D; 5) Under the condition of inert atmosphere, high temperature calcination is adopted in the tube furnace to completely carbonize the surface coating of the intermediate product D to obtain the carbonized intermediate product E; 6) taking out the intermediate product E, placing it in the etching solution with stirring and etching, performing suction filtration and washing to neutrality after the etching to obtain the intermediate product F; 7) After drying the intermediate product F in a vacuum drying oven, grinding to obtain carbon nano hemispherical particles of the product of the present invention. 2. the preparation method of carbon nano hemispherical particles according to claim 1, is characterized in that: in step 1), described organosilicon is selected from propyl orthosilicate, tetrapropoxysilane, tetraethylorthosilicate one or more of; Preferably, in step 1), the amount of the organosilicon is 3-12mL; the amount of anhydrous ethanol is 70-150mL. 3. the preparation method of carbon nano hemisphere particle according to claim 1, is characterized in that: in step 2), described alkali is selected from concentrated ammonia water, sodium hydroxide or lysine; Preferably, in step 2), the concentration of the alkaline aqueous solution is 25-30 wt %, and the dosage is 2-10 mL. 4. The preparation method of carbon nano hemispherical particles according to claim 1, characterized in that: in step 3), the temperature of the heating and stirring is 25-40°C; and the reaction process is sealed; Preferably, in step 3), the heating and stirring are performed using a water bath; the heating and stirring time is 10-40 minutes; Preferably, in step 3), the formaldehyde comes from 18wt% formaldehyde solution, which contains 5-8wt% methanol stabilizer, and the amount of the formaldehyde solution is 0.56-1.4mL; the amount of the resorcinol is 0.4 mL -1g; Preferably, in step 3), the reaction time of the phenolic condensation reaction is 3-24h. 5. the preparation method of carbon nano hemispherical particles according to claim 1, is characterized in that: in step 4), described centrifugal washing refers to successively with deionized water and dehydrated alcohol ultrasonic washing and centrifugal separation, to after centrifugal The secondary liquid is anhydrous and clear and transparent; the rotational speed of the centrifugation is 1000-6000rpm; Preferably, in step 4), the vacuum degree in the vacuum drying box is 0.08-0.12MPa. 6. the preparation method of carbon nano hemispherical particles according to claim 1, is characterized in that: in step 5), described inert atmosphere is nitrogen or helium; Preferably, in step 5), the temperature of the high-temperature calcination is 700-900° C., the heating gradient is 1-10K/min, and the time is 1-2h. 7. the preparation method of carbon nano hemispherical particles according to claim 1, is characterized in that: in step 6), described etching solution is selected from sodium hydroxide solution or hydrofluoric acid solution; Preferably, in step 6), when the etching solution adopts sodium hydroxide solution, its concentration is 3-5M; Preferably, in step 6), the temperature of the stirring etching is 78-82° C. and the time is 8-24 h. 8 . The method for preparing carbon nano hemispherical particles according to claim 1 , wherein in step 7), the degree of vacuum in the vacuum drying box is 0.08-0.12 MPa. 9 . 9 . The method for preparing carbon nano hemispherical particles according to claim 1 , wherein in step 7), the temperature in the vacuum drying oven is 40-70° C., and the drying time is 12-24 h. 10 .

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