CN116409780B

CN116409780B - Heteroatom doped hollow carbon nanosphere suitable for various hollow structures and preparation method thereof

Info

Publication number: CN116409780B
Application number: CN202310352815.5A
Authority: CN
Inventors: 吕荣文; 宋财城
Original assignee: Dalian University of Technology
Current assignee: Dalian University of Technology
Priority date: 2023-04-04
Filing date: 2023-04-04
Publication date: 2024-03-26
Anticipated expiration: 2043-04-04
Also published as: CN116409780A

Abstract

The invention discloses a preparation method of a heteroatom doped hollow carbon nanosphere, which comprises the following steps: the method comprises the steps of (1) taking melamine as a raw material, taking an anionic surfactant as a template agent, taking aromatic amine-acid as a pH regulator to keep the system acidic, and taking amino groups of the melamine in the system as organic counter ions to form an 'anionic-cationic surfactant' and a self-adaptive vesicle template between the organic counter ions and the template agent; introducing a template auxiliary agent to convert the self-adaptive vesicle template into a multi-shell vesicle; introducing fatty aldehyde and aromatic amine-acid to form a Schiff base intermediate, adding melamine to Schiff base imine bonds, performing cross-linking polymerization to obtain polymer nanospheres, and carbonizing to obtain hollow carbon nanospheres. The method has the advantages of simple operation, rapid reaction, mild condition, capability of realizing the preparation of the heteroatom doped hollow carbon nanospheres in various forms including a core-shell structure, a single-shell structure and a multi-shell structure by simple regulation and control, and wide practical application prospect.

Description

Heteroatom doped hollow carbon nanosphere suitable for various hollow structures and preparation method thereof

Technical Field

The invention belongs to the technical field of new nano materials, and particularly relates to a preparation method of a heteroatom doped hollow carbon nanosphere suitable for various hollow structural forms.

Background

Hollow micro/nanostructured materials with internal cavities have attracted extensive attention and research interest in chemistry and materials science. This research hot trend has greatly driven the rapid development of hollow nanomaterial composition sources (including silicon, silica, metals, metal oxides, polymers, carbon, etc.) and hollow building forms (including single shell, multiple shell, core shell, etc.). The hollow carbon nanospheres are widely applied to the fields of catalysis, biomedicine, environmental treatment, energy storage and the like due to the characteristics of low density, high stability, excellent conductivity, controllable porosity, surface functionalization, high surface area-volume ratio, internal and external environment isolation, controlled release and the like caused by the synergistic effect among special internal hollow structures.

Typical methods for preparing the hollow carbon nanospheres at present are a soft/hard template method, a limited space pyrolysis method, a template-free methodSystem derivatization methods, and the like. However, the studies based on the above-described method are mainly of a single-shell hollow structure, and only one of a plurality of hollow structural forms can be prepared. The preparation of the multi-shell hollow structure carbon nanospheres with complex structures can only be obtained by adopting a layer by layer coating/shell by shell means based on the methods. The method is limited by the properties of the carbon precursor, and the complicated operation means greatly limit the practical application prospect of the multi-shell hollow carbon sphere. In addition, the existing multi-shell hollow carbon nanospheres are mainly in a simple ball-in-ball structure form, and the multi-shell structure form of a ball-in-column structure with anisotropy and a self-supporting structure is not reported at present.

Research shows that the heteroatom doping can change the electron donor-acceptor property of carbon and change the local electron cloud density of carbon, so that the chemical property of the material is improved, for example, the adsorption capacity of the material to greenhouse gas acid gas carbon dioxide and the electrochemical property of the material can be effectively improved by introducing nitrogen and sulfur atoms into the carbon material. The doping of the heteroatoms can be classified as in-situ doping and post-treatment doping from the introduction timing of the heteroatoms. Melamine is an ideal nitrogen source feed material due to its rich nitrogen content (66.7%) and low cost. At present, melamine is used as a nitrogen source, raw materials rich in hydroxyl groups such as aromatic phenol (phenol, resorcinol, phloroglucinol), glucose, starch and the like are used as carbon sources, and the corresponding target carbon sphere material is prepared by regulating acid-base catalysis to carry out hydrothermal (70-180 ℃) copolymerization, namely in-situ doping. There are also nitrogen-doped carbon materials obtained by mixing melamine with a carbon source at high temperature (500-800 ℃) and performing a post-treatment. However, the above-mentioned problems of unavoidable severe reaction conditions, complicated operation procedures, low material utilization, etc. of the preparation route have prevented the industrial-scale mass-production application thereof.

Disclosure of Invention

The invention aims to provide a preparation method of a heteroatom doped hollow carbon nanosphere suitable for various hollow structural forms, which aims to solve the problems that the prior art is difficult to prepare a multi-shell structure of a sphere center column with anisotropy and a self-supporting structure at low temperature, and the prior art has strict and complex reaction conditions and flow and low material utilization rate, so that industrial mass production is difficult to realize.

In order to achieve the above object, the present invention provides a method for preparing a heteroatom doped hollow carbon nanosphere, comprising the steps of: the method comprises the steps of (1) keeping a system acidic by taking aromatic amine-acid as a pH regulator, taking melamine as a raw material, taking an anionic surfactant as a template agent, enabling amino groups of the melamine to be protonated and to interact with the anionic surfactant as organic counter ions to form an anionic-cationic surfactant, and constructing and forming a self-adaptive vesicle template; introducing fatty aldehyde to form a Schiff base intermediate, adding melamine to an imine bond of the Schiff base intermediate, and performing cross-linking polymerization to obtain a polymer nanosphere; and carbonizing to obtain the hollow carbon nanospheres.

Preferably, the anionic surfactant is one of sodium bis (2-ethylhexyl) sulfosuccinate, straight-chain dioctyl sodium sulfosuccinate and sodium dodecyl benzene sulfonate; when the core-shell hollow carbon spheres are prepared, the concentration is more than 0 and less than 1mmol/L; when the multi-shell structure is prepared, the concentration is more than 0 and less than the critical micelle concentration.

Preferably, the method for constructing the adaptive vesicle template comprises the following steps:

s1, dissolving the template agent in water at the temperature of 0-30 ℃, adding a template auxiliary agent, and stirring until a uniform emulsion system is formed;

s2, completely dissolving melamine and aromatic amine-acid in water at the temperature of 0-30 ℃;

and S3, adding the emulsion system formed in the step S1 into the step S2 to obtain the emulsion.

Preferably, the template auxiliary agent is one of 1,3, 5-trimethylbenzene, 1,3, 5-triethylbenzene and 1,3, 5-triisopropylbenzene; the template auxiliary agent dosage is 0.5-5 times of the template agent mass.

Preferably, the fatty aldehyde is one of formaldehyde, acetaldehyde, glyoxal, glutaraldehyde and glyoxal; the amount of fatty aldehyde is 1 equivalent or more of melamine.

Preferably, the carbonization condition is that the carbonization temperature is 400-1000 ℃ and the carbonization time is 30-180min under the inert gas atmosphere; the inert gas comprises nitrogen and argon.

Preferably, the aromatic amine-acid is one of meta-acid, 2, 5-diaminobenzenesulfonic acid, 2-aminobenzenesulfonic acid, 3-aminobenzenesulfonic acid, 4-aminobenzenesulfonic acid, 2, 3-diaminobenzoic acid, 3, 5-diaminobenzoic acid, 3, 4-diaminobenzoic acid, 2, 5-diaminobenzoic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid; the aromatic amine-acid amount is 5% -50% of the melamine molar amount.

Preferably, the polymer nanospheres are subjected to solid-liquid separation and then are subjected to drying treatment; the solid-liquid separation method comprises suction filtration and centrifugation; the drying method comprises freeze drying, room temperature drying or heat drying.

The invention provides a heteroatom doped hollow carbon nanosphere prepared by the preparation method of the heteroatom doped hollow carbon nanosphere.

Compared with the prior art, the invention has the beneficial effects that:

1. the method adopts a brand new synthetic route, and under the mild condition of 0-30 ℃, the milky precipitate is generated only by 10s reaction, and the reaction can be stopped as required within 5-360 min; avoiding the relatively harsh (70-180 ℃) and lengthy preparation conditions used by the traditional melamine resin, melamine-phenolic resin and other preparation processes of hollow structures of the same type; greatly reduces the dependence on high quality reaction equipment and reduces the mass production cost.

2. Compared with the conventional soft template method, the method disclosed by the invention has the advantages that the template is formed spontaneously, the template agent is low in use amount and low in cost; compared with a hard template method or a pseudo template-free method which are more used for traditional hollow materials, the method is simple to operate, avoids the problems of difficult template removal and the like, greatly reduces chemical reagents used in the template removal process, reduces the preparation cost, and is environment-friendly.

3. The method can control the structure of the target product by regulating and controlling the reaction parameters under the same system, has more flexibility compared with the traditional single-structure production process, and is suitable for large-scale production.

4. The method of the invention rarely realizes one-step preparation of the multi-shell hollow carbon nanospheres doped with hetero atoms. Compared with the traditional hard template method or layer-by-layer coating process route adopted by the multi-shell hollow carbon sphere, the method is simpler, can be prepared in situ only by one step, greatly simplifies the operation flow of the process, and promotes the practical application process of the multi-shell hollow carbon sphere.

5. The shape of the sphere center column of the multi-shell hollow carbon nanospheres doped with the hetero atoms is different in different shooting angles, which is not reported in all related processes at present, and meanwhile, the sphere center column is rarely prepared directly by adopting a soft template method in all multi-shell hollow carbon nanospheres, and the sphere center column can still keep stable after being amplified and synthesized in a 10-time scale. This clearly reduces the practical application threshold of the multi-shell hollow material, and is beneficial to mass production.

Drawings

FIG. 1 is a TEM image of heteroatom doped hollow carbon nanospheres prepared according to the invention at different AOT amounts at 30 ℃;

FIG. 2 is a TEM image of heteroatom-doped hollow carbon nanospheres prepared according to the invention at different stirring rates at 30 ℃;

FIG. 3 is a TEM image of heteroatom doped biopolymer spheres prepared according to the present invention at various reaction times at 30 ℃;

FIG. 4 is a TEM image of heteroatom doped hollow carbon nanospheres prepared according to the invention at 30℃with different TMB amounts;

FIG. 5 is a TEM image of the present invention for preparing heteroatom doped hollow carbon nanospheres by adding 1,3, 5-triethylbenzene at 30deg.C;

FIG. 6 is a TEM image of heteroatom doped hollow carbon nanospheres prepared according to the invention at 30℃with different formaldehyde levels;

FIG. 7 is a TEM image of heteroatom-doped hollow carbon nanospheres prepared with different melamine amounts at 30deg.C according to the present invention;

FIG. 8 is a TEM image of heteroatom-doped hollow carbon nanospheres prepared according to the invention at 30℃with different amounts of isophthalic acid;

FIG. 9 is an SEM image of the heteroatom-doped hollow carbon nanospheres prepared in accordance with the invention at 30deg.C;

FIG. 10 is a TEM image of heteroatom-doped hollow carbon nanospheres prepared according to the invention at different reaction temperatures;

FIG. 11 is a multi-angle transmission electron microscope of the heteroatom doped multi-shell hollow carbon sphere of the present invention;

FIG. 12 is a HRTEM diagram of a heteroatom-doped multi-shell hollow carbon nanosphere of the present invention;

FIG. 13 is an elemental distribution of a heteroatom-doped multi-shell hollow carbon sphere of the present invention;

FIG. 14 is a TEM image of a hollow carbon nanosphere of the present invention at 10 Xmagnification;

FIG. 15 is a TEM image of the reaction of 2, 5-diaminobenzenesulfonic acid in the present invention to produce carbon hollow carbon nanospheres;

FIG. 16 is a TEM image of the preparation of carbon hollow carbon nanospheres by the participation of 2-aminobenzenesulfonic acid in the reaction of the present invention;

FIG. 17 is a TEM image of the preparation of carbon hollow carbon nanospheres according to the invention by participation of 3-aminobenzenesulfonic acid in the reaction;

FIG. 18 is a TEM image of the preparation of carbon hollow carbon nanospheres according to the invention by the participation of 4-aminobenzenesulfonic acid in the reaction;

FIG. 19 is a TEM image of the reaction of 2, 3-diaminobenzoic acid of the present invention to produce carbon hollow carbon nanospheres;

FIG. 20 is a TEM image of the reaction of 3, 5-diaminobenzoic acid according to the invention to produce carbon hollow carbon nanospheres;

FIG. 21 is a TEM image of the reaction of 2-aminobenzoic acid of the present invention to produce carbon hollow carbon nanospheres;

FIG. 22 is a TEM image of the reaction of 3-aminobenzoic acid of the present invention to produce carbon hollow carbon nanospheres;

FIG. 23 is a TEM image of the preparation of hollow carbon nanospheres according to the invention by the participation of 4-aminobenzoic acid;

FIG. 24 is a TEM image of the preparation of hollow carbon nanospheres by the acetaldehyde participation reaction of the present invention;

FIG. 25 is a TEM image of glyoxal-reacted to prepare hollow carbon nanospheres according to the present invention;

FIG. 26 is a TEM image of glutaraldehyde participating in the reaction of the present invention to prepare hollow carbon nanospheres;

FIG. 27 is a TEM image of the present invention with glyoxal participating in the reaction to produce hollow carbon nanospheres;

FIG. 28 is a TEM image of the sodium dioctyl sulfosuccinate (straight chain) of the present invention produced in a reaction to produce a nano-hollow carbon;

FIG. 29 is a TEM image of the sodium dodecyl benzene sulfonate of the present invention participating in the reaction to prepare hollow carbon nanospheres;

FIG. 30 is an X-ray energy spectrum analysis chart of the hollow carbon nanospheres with the heteroatom-doped core-shell structures of the invention;

FIG. 31 is an X-ray energy spectrum analysis chart of the heteroatom doped multi-shell structure hollow carbon nanospheres of the present invention;

FIG. 32 is a graph showing the nitrogen adsorption and desorption curves and pore size distribution of the heteroatom-doped core-shell carbon nanospheres of the present invention;

FIG. 33 is a graph showing the nitrogen adsorption and desorption curves and pore size distribution of the heteroatom-doped single shell hollow carbon nanospheres of the present invention;

FIG. 34 is a graph showing the nitrogen adsorption and desorption curves and pore size distribution of the heteroatom-doped multi-shell hollow carbon nanospheres of the present invention;

FIG. 35 is a thermogravimetric analysis of an atom doped hollow carbon nanosphere of the present invention;

FIG. 36 is a physical diagram showing the state of an emulsion of the present invention after a template agent and an adjuvant are mixed at 30 ℃;

FIG. 37 is a physical view showing a state after the melamine and the surfactant are mixed;

FIG. 38 is a schematic representation of the present invention in a state after mixing the surfactant with the meta-acid;

FIG. 39 is a physical diagram of the system state of the invention after the template and the precursor are mixed at 30 ℃;

FIG. 40 is a schematic diagram showing the state of the system after completion of the reaction at 30 ℃.

Detailed Description

The invention is further illustrated below in connection with specific examples, but is not limited in any way.

The instruments, reagents, materials, etc. used in the examples described below are conventional instruments, reagents, materials, etc. known in the art, and are commercially available. The experimental methods, detection methods, and the like in the examples described below are conventional experimental methods, detection methods, and the like that are known in the prior art unless otherwise specified.

The invention provides a preparation method of heteroatom doped hollow carbon nanospheres in various simple, efficient and economic hollow structural forms, which comprises the following steps: at 0-30 ℃, melamine is taken as a main raw material, an anionic surfactant is taken as a template agent, the melamine is acidic through an aromatic amine-acid regulation system, the amino group of the melamine in the state is protonated and is used as an organic counter ion to interact with the surfactant based on coulomb force, so that an 'anionic-cationic surfactant' is constructed, an adaptive vesicle template (namely, an adaptive template) is spontaneously formed, and a conventional vesicle can be converted into a multi-shell vesicle by introducing a template auxiliary agent; after fatty aldehyde is introduced, a Schiff base intermediate is preferentially formed between the fatty aldehyde and aromatic amine-acid in the system, and after addition polymerization is carried out on Schiff base imine bonds by melamine, polymer nanospheres are obtained, and hollow carbon nanospheres are obtained after carbonization.

Wherein, the template auxiliary agent is embedded into the hydrophobic section of the template agent; adding aromatic amine-acid to adjust the reaction system to be acidic, constructing a final template, namely a vesicle template (self-adaptive template) through ionic interaction between the protonated amino groups of the melamine and the template agent, enabling the aromatic amine-acid to act with fatty aldehyde as a reaction initiator to generate Schiff base, adding the amino-rich melamine to Schiff base imine bonds, quickly forming a heteroatom doped polymer nanosphere in a short time, and directly carbonizing to obtain the heteroatom doped hollow carbon nanosphere. The method can be used for efficiently and massively preparing hollow carbon nanospheres with uniform heteroatom doping and stable structure, and can obtain various hollow structure carbon nanospheres by simply changing reaction parameters.

Further, the method comprises the following steps:

(1) Dissolving surfactant in water at 0-30deg.C;

(2) Adding a template auxiliary agent into the system (1), and forming a light gray/light white uniform emulsion system by an ultrasonic instrument or intense stirring for more than 6 hours;

(3) Completely dissolving melamine and aromatic amine-acid in water at 0-30deg.C;

(4) Adding the emulsion formed in the step (2) into the step (3) and stabilizing the emulsion for at least one hour at the stirring speed of 0-1000rpm to form a light blue/light gray/light milky stable system;

(5) Adding fatty aldehyde into the system in the step (4), and reacting for a certain time at a stirring speed of 0-1000rpm to obtain a corresponding polymer;

(6) Carrying out solid-liquid separation on the polymer obtained in the step (5), and then drying the product;

(7) Then carrying out high-temperature carbonization treatment in an inert gas atmosphere to obtain the heteroatom doped hollow carbon nanospheres; the inert gas comprises nitrogen and argon.

Wherein the template agent is one of sodium bis (2-ethylhexyl) sulfosuccinate (AOT), dioctyl sodium sulfosuccinate or Sodium Dodecyl Benzene Sulfonate (SDBS), and the template auxiliary agent is one of 1,3, 5-trimethylbenzene, 1,3, 5-triethylbenzene and 1,3, 5-triisopropylbenzene; the fatty aldehyde is one of formaldehyde, acetaldehyde, glyoxal, glutaraldehyde and glyoxal.

Wherein, the most preferred temperature in the step (1) is 30 ℃, the stable system is ensured, no foam is formed, meanwhile, the use amount of the surfactant is selected according to the structure of the target product, so as to prepare the core-shell hollow carbon sphere, the use concentration of the core-shell hollow carbon sphere is not more than 1mmol/L, the use concentration of the multi-shell structure is not more than the critical micelle concentration of the multi-shell structure, namely, the use concentration of the multi-shell structure is not more than 2.5mmol/L when the reaction temperature is 30 ℃.

Wherein the most preferred temperature in step (2) is 20℃and the template aid should be added rapidly below the liquid surface. The amount of the template auxiliary agent is regulated and controlled according to the structure of the target product, and the mass ratio or the mole ratio of the amount of the surfactant adopted in the step (1) is generally convenient to operate, and the use amount of the template auxiliary agent is 0.5-5 times of the mass of the surfactant by taking 1,3, 5-trimethylbenzene as an example.

Wherein the most preferred temperature of step (3) is 30 ℃, wherein the aromatic amine-acid is one of isophthalic acid (2, 4-diaminobenzenesulfonic acid), 2, 5-diaminobenzenesulfonic acid, 2-aminobenzenesulfonic acid, 3-aminobenzenesulfonic acid, 4-aminobenzenesulfonic acid, 2, 3-diaminobenzoic acid, 3, 5-diaminobenzoic acid (3, 5-diaminobenzoic acid), 3, 4-diaminobenzoic acid, 2, 5-diaminobenzoic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, and the amount used is 5% -50% of the amount of melamine material.

Wherein, the stirring speed involved in the step (4) can be regulated and controlled according to the requirement on the structure of the target product, and the most preferable rotating speed is 0-500rpm.

Wherein, the fatty aldehyde in the step (5) is introduced into the reaction system in a mode of fast transferring to, and the using amount of the fatty aldehyde is 1 equivalent or more of the using amount of melamine. The stirring rate of the reaction is regulated according to the structure of the target product, and the most preferable stirring rate is consistent with the stirring rate in the step (4).

Wherein, after the fatty aldehyde is added in the step (5), the reaction time is 1-360min, and most preferably 180min;

wherein, in the step (6), the solid-liquid separation of the product can adopt suction filtration, centrifugation and other effective means. If the particle size is selective, further sieving can be performed by varying the centrifugation rate and fixing the pore size of the filter membrane.

In the above technical solution, the drying temperature of the product in step (6) may be freeze drying, room temperature drying, and heat drying (room temperature-100 ℃).

Wherein the carbonization temperature in the step (7) can be selected to be 400-1000 ℃ or above, and the heteroatom content in the carbonized product can be changed by the carbonization temperature. Further preferably, the carbonization temperature is 500-800 ℃.

In the method, melamine is used as a main raw material, aromatic amine-acid is used as a Schiff base initiator and the regulation system is acidic, in this state, amino groups of the melamine are protonated, and form a 'anionic-cationic surfactant' through coulomb force interaction with a surfactant, and spontaneously form vesicles, and a template auxiliary agent is introduced to promote the conversion of single-layer vesicles into multi-layer vesicles (self-adaptive templates). After fatty aldehyde is introduced, a Schiff base intermediate is formed by the fatty aldehyde and aromatic amine-acid, then melamine is used for adding Schiff base imine bonds, polymer nanospheres are obtained after further crosslinking polymerization, and the target heteroatom doped hollow carbon nanospheres are obtained after carbonization and pyrolysis. By changing experimental parameters such as the usage amount of the surfactant, the usage amount of the template auxiliary agent, the reaction temperature, the stirring rate of the reaction, the usage amount of the basic raw materials, the reaction time, the carbonization temperature and the like, the heteroatom-doped hollow carbon nanospheres with various hollow structural forms, such as the heteroatom-doped single-shell hollow carbon nanospheres, the heteroatom-doped core-shell hollow carbon nanospheres, the heteroatom-doped multi-shell hollow carbon nanospheres and the like, can be realized. The prepared material has the advantages of controllable particle size, uniform heteroatom distribution, adjustable content, stable structure and good dispersibility.

The particle size of the heteroatom doped hollow carbon nanospheres prepared by the invention is between 100nm and 1 mu m, and the particle size is controllable. The content of elemental nitrogen is 5% -50%, the content of sulfur is 0.1% -8% and the content is adjustable; the comparison area of the disclosed heteroatom doped hollow carbon nanospheres is 300-800m ² Per gram, pore volume of 0.5-1.0cm ³ And/g. The material has abundant micropores and abundant mesopores, wherein the pore diameter of the micropores is between 0.5 and 2nm, and the pore diameter of the mesopores is between 2 and 25 nm.

Another aspect of the invention is that: the heteroatom doped hollow carbon nanospheres in various hollow forms including a core-shell hollow structure, a single-shell hollow structure, a multi-shell hollow structure and a large core-shell hollow structure can be realized by changing the usage amount of the template auxiliary agent in the synthesis strategy.

Example 1

At room temperature, 0.01-0.1g of AOT is taken at intervals of 0.01g and is completely dissolved in 10mL of water to be marked as solution A; 0.252g (2 mmol) of melamine and 0.113g (0.6 mmol) of isophthalic acid are dissolved in 90mL of water at 30℃and are designated as solution B. Transfer solution A completely to solution B and hold at 30℃and 300rpm stirring rate for at least 1h, then add 3mL of formaldehyde solution and continue the reaction under the above conditions, begin to appear clear white turbidity after 30s and stop the reaction after 180 min. And (3) centrifuging, washing, drying and carbonizing the obtained milky turbid liquid, and then carrying out transmission electron microscope characterization, wherein a-h are the influences on the morphology of the heteroatom-doped hollow carbon nanospheres when 0.02-0.09g of AOT is taken, respectively, as shown in a figure 1. The results show that different amounts of AOT have influence on the hollow structure of the product, and the product structure is changed into a single-shell hollow and multi-shell structure from a core-shell structure with the increase of the use amount of the AOT.

Example 2

At room temperature, 0.02g of AOT is taken and completely dissolved in 10mL of water, then 0.01g of TMB is added and vigorously stirred for more than 6 hours to form a uniform light white system, which is marked as solution A; 0.252g (2 mmol) of melamine and 0.113g (0.6 mmol) of isophthalic acid are dissolved in 90mL of water at 30℃and are designated as solution B. Transfer solution A completely to solution B and hold at 30℃and stirring speed of 0, 250, 500, 750, 1000rpm for at least 1h, then add 3mL of formaldehyde solution and continue the reaction under the above conditions, start to appear clear white turbidity after 30s and stop the reaction after 180 min. And (3) centrifuging, washing, drying and carbonizing the obtained milky turbid liquid, and then carrying out transmission electron microscope characterization, wherein a-e are the influences on the morphology of the heteroatom-doped hollow carbon nanospheres when the stirring speed is 0, 250, 500, 750 and 1000rpm respectively, as shown in figure 2. The results show that the product structure is basically consistent at the rotating speed of 0-500rpm, further explaining the spontaneity and stability of the process, and the structure is destroyed at the too high stirring speed, which is the result of the destruction of the template in the system by the shearing force of water flow caused by the high rotating speed.

Example 3

At room temperature, 0.02g of AOT is taken and completely dissolved in 10mL of water, then 0.01g of TMB is added and vigorously stirred for more than 6 hours to form a uniform light white system, which is marked as solution A; 0.252g (2 mmol) of melamine and 0.113g (0.6 mmol) of isophthalic acid are dissolved in 90mL of water at 30℃and are designated as solution B. Transfer solution A completely to solution B and hold at 30℃and 300rpm stirring rate for at least 1h, then add 3mL of formaldehyde solution and continue the reaction under the above conditions, begin to appear clear white turbidity after 30s, terminate the reaction after 5min, 30min, 60min, 90 min. And (3) centrifuging, washing, drying and carrying out transmission electron microscope characterization on the obtained milky turbid liquid, wherein a-d are the shapes of the heteroatom doped hollow carbon nanospheres with the reaction time of 5min, 30min, 60min and 90min respectively as shown in figure 3. The result shows that the corresponding multi-shell structure can be obtained after the reaction is carried out for 5min, but the multi-shell structure of the target product is clearer and more complete after the reaction is carried out for more than 30 min.

Example 4

At room temperature, 0.02g of AOT is taken and completely dissolved in 10mL of water, and then 0.01g, 0.02g, 0.04g, 0.06g, 0.08g and 0.1g of TMB are added and vigorously stirred for more than 6 hours to form a uniform light white system, which is marked as solution A; 0.252g (2 mmol) of melamine and 0.113g (0.6 mmol) of isophthalic acid are dissolved in 90mL of water at 30℃and are designated as solution B. Transfer solution A completely to solution B and hold at 30℃and 300rpm stirring rate for at least 1h, then add 3mL of formaldehyde solution and continue the reaction under the above conditions, begin to appear clear white turbidity after 30s and stop the reaction after 180 min. The milky turbid liquid is subjected to centrifugation, washing, drying and carbonization, and is subjected to transmission electron microscope characterization, as shown in fig. 4, wherein a-f are the effects of using 0.01g, 0.02g, 0.04g, 0.06g, 0.08g and 0.1g of TMB on heteroatom doped hollow carbon nanospheres. The results show that for the preparation of the multi-shell hollow structure, the using amount of TMB should not exceed 0.04g, and for the preparation of the large core-shell hollow structure, the using amount of TMB should be between 0.06g and 0.1 g.

Example 5

At room temperature, 0.02g of AOT is taken and completely dissolved in 10mL of water, then 0.01g of 1,3, 5-triethylbenzene is added and vigorously stirred for more than 6 hours to form a uniform light white system, which is marked as solution A; 0.252g (2 mmol) of melamine and 0.113g (0.6 mmol) of isophthalic acid are dissolved in 90mL of water at 30℃and are designated as solution B. Transfer solution A completely to solution B and hold at 30℃and 300rpm stirring rate for at least 1h, then add 3mL of formaldehyde solution and continue the reaction under the above conditions, begin to appear clear white turbidity after 30s and stop the reaction after 180 min. And centrifuging, washing, drying and carbonizing the obtained milky turbid liquid, and performing transmission electron microscope characterization. Fig. 5 is a heteroatom doped hollow carbon nanosphere prepared by substituting TMB with 1,3, 5-triethylbenzene. The result shows that when 1,3, 5-triethylbenzene is used as a template auxiliary agent, the heteroatom doped hollow carbon nanospheres with the single-layer hollow structure as the main component can be prepared

Example 6

At room temperature, 0.02g of AOT is taken and completely dissolved in 10mL of water, then 0.01g of TMB is added and vigorously stirred for more than 6 hours to form a uniform light white system, which is marked as solution A; 0.252g (2 mmol) of melamine and 0.113g (0.6 mmol) of isophthalic acid are dissolved in 90mL of water at 30℃and are designated as solution B. Transfer solution A completely to solution B and hold at 30℃and 300rpm stirring rate for at least 1h, then add 0.25mL, 0.5mL, 0.75mL, 1.5mL, 2.25mL, 3mL formaldehyde solution and continue the reaction under the above conditions, begin to appear clear white turbidity after 30s, and terminate the reaction after 180 min. And (3) centrifuging, washing, drying and carbonizing the obtained milky turbid liquid, and then carrying out transmission electron microscope characterization, wherein a-f respectively represent the influence of formaldehyde with the dosage of 0.25mL, 0.5mL, 0.75mL, 1.5mL, 2.25mL and 3mL on the heteroatom-doped hollow carbon nanospheres as shown in figure 6. The result shows that the number of the shells of the prepared multi-shell hollow carbon nanospheres is small, and the number of the layers is increased when the formaldehyde amount is relatively large.

Example 7

At room temperature, 0.02g of AOT is taken and completely dissolved in 10mL of water, then 0.01g of TMB is added and vigorously stirred for more than 6 hours to form a uniform light white system, which is marked as solution A; 0.126g, 0.63g of melamine and 0.113g (0.6 mmol) of an isophthalic acid were dissolved in 90mL of water at 30℃and designated as solution B. Transfer solution A completely to solution B and hold at 30℃and 300rpm stirring rate for at least 1h, then add 3mL of formaldehyde solution and continue the reaction under the above conditions, begin to appear clear white turbidity after 30s and stop the reaction after 180 min. The milky turbid liquid is subjected to centrifugation, washing, drying and carbonization, and is subjected to transmission electron microscope characterization, as shown in fig. 7, wherein a-b represent the influence of melamine with the dosage of 0.126g and 0.63g on the heteroatom doped hollow carbon nanospheres. The result shows that the shell thickness of the product can be controlled by controlling the usage amount of melamine.

Example 8

At room temperature, 0.02g of AOT is taken and completely dissolved in 10mL of water, then 0.01g of TMB is added and vigorously stirred for more than 6 hours to form a uniform light white system, which is marked as solution A; 0.252g (2 mmol) of melamine and 0.0376g, 0.0752g, 0.15g, 0.188g of an isophthalic acid are dissolved in 90mL of water at 30℃and designated as solution B. Transfer solution A completely to solution B and hold at 30℃and 300rpm stirring rate for at least 1h, then add 3mL of formaldehyde solution and continue the reaction under the above conditions, begin to appear clear white turbidity after 30s and stop the reaction after 180 min. The obtained milky turbid liquid is subjected to centrifugation, washing, drying and carbonization, and is subjected to transmission electron microscope characterization, as shown in fig. 8, wherein a-d respectively represent the influence of different amounts of meta-acid on the heteroatom doped hollow carbon nanospheres. The result shows that when the amount of the meta-acid is 0.0376g and 0.0752g, the number of the shell layers of the prepared multi-shell hetero-atom doped hollow carbon nanospheres is more, and the thickness of the shell layers is small; when the amount of meta-acid increases, the number of shell layers decreases, the thickness of the shell layers increases, and even a single-layer hollow structure appears.

Example 9

At room temperature, 0.02g of AOT is taken and completely dissolved in 10mL of water, then 0.01g of TMB is added or TMB is not added, and the mixture is vigorously stirred for more than 6 hours to form a uniform light white system, and the uniform light white system is marked as solution A; 0.252g (2 mmol) of melamine and 0.113g (0.6 mmol) of isophthalic acid are dissolved in 90mL of water at 30℃and are designated as solution B. Transfer solution A completely to solution B and hold at 30℃and 300rpm stirring rate for at least 1h, then add 3mL of formaldehyde solution and continue the reaction under the above conditions, begin to appear clear white turbidity after 30s and stop the reaction after 180 min. And centrifuging, washing, drying and carbonizing the obtained milky turbid liquid, and carrying out SEM (scanning electron microscope) electron microscope characterization. Fig. 9 shows the morphology of the heteroatom-doped hollow carbon nanospheres, a and b being different magnifications, showing that the prepared material is typically spherical in morphology.

Example 10

At room temperature, 0.02g of AOT is taken and completely dissolved in 10mL of water, then 0.01g of TMB is added and vigorously stirred for more than 6 hours to form a uniform light white system, which is marked as solution A; 0. 0.252g (2 mmol) of melamine and 0.113g (0.6 mmol) of isophthalic acid are dissolved in 90mL of water at 15℃and are designated as solution B. Transfer solution A completely to solution B and hold at 0, 15℃and 300rpm stirring rate for at least 1h, then add 3mL of formaldehyde solution and continue the reaction under the above conditions, begin to appear visibly white turbidity after 30s and stop the reaction after 180 min. And centrifuging, washing, drying and carbonizing the obtained milky turbid liquid, and performing transmission electron microscope characterization. In FIG. 10, a and b are TEM images of heteroatom-doped hollow carbon nanospheres prepared at 0℃and 15℃respectively. The results show that the temperature has a decisive influence on the structure of the target product, which is caused by the different behaviors of the surfactant at different temperatures.

Example 11

The heteroatom doped multi-shell hollow carbon sphere prepared by the invention is in an unconventional sphere-in-sphere shape, but is similar to a sphere-in-column structure. The ball-in-ball form is that the images are all the same and are shot from all angles through a transmission electron microscope; when the multi-shell hollow carbon sphere in the form of the 'sphere center column' prepared by the invention is shot by a transmission electron microscope, the shot patterns are different when the sphere is at different angles, as shown in fig. 11a, and the circular rose-like shape, the oval shape or the oblate shape are shown in the figure. When the multi-shell hollow carbon sphere is photographed in a perfect circle form, the form shown in fig. 11b and 11c is presented, and if the multi-shell hollow carbon sphere is photographed at other angles, the form is presented as shown in fig. 11d. For easy understanding, the structure is imagined to be similar to onion in overall form and internal structure, and is similar to onion-shaped heteroatom doped multi-shell hollow carbon nanospheres.

Example 12

At room temperature, 0.02g of AOT is taken and completely dissolved in 10mL of water, then 0.01g of TMB is added and vigorously stirred for more than 6 hours, and the mixture is marked as solution A; 0.252g (2 mmol) of melamine and 0.113g (0.6 mmol) of isophthalic acid are dissolved in 90mL of water at 30℃and are designated as solution B. Transfer solution A completely to solution B and hold at 30℃and 300rpm stirring rate for at least 1h, then add 3mL of solution A and continue the reaction under the above conditions, begin to appear clear white turbidity after 30s and stop the reaction after 180 min. And (3) centrifuging, washing, drying and carbonizing the obtained milky turbid liquid, and then carrying out high-resolution transmission electron microscopy and element distribution energy spectrum characterization on the sample, wherein the high-resolution transmission electron microscopy and element distribution energy spectrum characterization are shown in figures 12 and 13. Fig. 12 shows that the multi-shell hollow carbon nanospheres doped with hetero atoms have rich pore structures, and fig. 13 shows that C, N, O, S and other elements are uniformly distributed in the material, thus showing excellent hetero atom doping characteristics.

Example 13

At room temperature, 0.2g of AOT is taken and completely dissolved in 100mL of water, then 0.1g of TMB is added and vigorously stirred for more than 6 hours, and the mixture is marked as solution A; 2.52g (20 mmol) of melamine and 1.13g (6 mmol) of isophthalic acid are dissolved in 900mL of water at 30℃and are designated as solution B. Transfer solution A completely to solution B and hold at 30℃and 300rpm stirring rate for at least 1h, then add 30mL of formaldehyde solution and continue the reaction under the above conditions, begin to appear clear white turbidity after 30s and stop the reaction after 180 min. And centrifuging, washing, drying and carbonizing the obtained milky turbid liquid, and then carrying out transmission electron microscope characterization. Fig. 14 is a TEM image of a heteroatom-doped hollow carbon nanosphere synthesized with a 10-fold magnification of the feed, and it can be seen that the morphology remains stable after the 10-fold scale-up.

Example 14

At room temperature, 0.02g of AOT is taken and completely dissolved in 10mL of water, then 0.01g of TMB is added and vigorously stirred for more than 6 hours to form a uniform light white system, which is marked as solution A; 0.252g (2 mmol) of melamine and 0.113g (0.6 mmol) of 2, 5-diaminobenzenesulfonic acid were dissolved in 90mL of water at 30℃and denoted as solution B. Transfer solution A completely to solution B and hold at 30℃and 300rpm stirring rate for at least 1h, then add 3mL of formaldehyde solution and continue the reaction under the above conditions, begin to appear clear white turbidity after 30s and stop the reaction after 180 min. And centrifuging, washing, drying and carbonizing the obtained milky turbid liquid, and performing transmission electron microscope characterization. Fig. 15 is a TEM image of the preparation of carbon hollow carbon nanospheres with the substitution of meta-acid with 2, 5-diaminobenzenesulfonic acid.

Example 15

At room temperature, 0.02g of AOT is taken and completely dissolved in 10mL of water, then 0.01g of TMB is added and vigorously stirred for more than 6 hours to form a uniform light white system, which is marked as solution A; 0.252g (2 mmol) of melamine and 0.104g (0.6 mmol) of 2-aminobenzenesulfonic acid were dissolved in 90mL of water at 30℃and designated as solution B. Transfer solution A completely to solution B and hold at 30℃and 300rpm stirring rate for at least 1h, then add 3mL of formaldehyde solution and continue the reaction under the above conditions, begin to appear clear white turbidity after 30s and stop the reaction after 180 min. And centrifuging, washing, drying and carbonizing the obtained milky turbid liquid, and performing transmission electron microscope characterization. Fig. 16 is a TEM image of the preparation of carbon hollow carbon nanospheres with the substitution of meta-acid with 2-aminobenzenesulfonic acid.

Example 16

At room temperature, 0.02g of AOT is taken and completely dissolved in 10mL of water, then 0.01g of TMB is added and vigorously stirred for more than 6 hours to form a uniform light white system, which is marked as solution A; 0.252g (2 mmol) of melamine and 0.104g (0.6 mmol) of 3-aminobenzenesulfonic acid were dissolved in 90mL of water at 30℃and designated as solution B. Transfer solution A completely to solution B and hold at 30℃and 300rpm stirring rate for at least 1h, then add 3mL of formaldehyde solution and continue the reaction under the above conditions, begin to appear clear white turbidity after 30s and stop the reaction after 180 min. And centrifuging, washing, drying and carbonizing the obtained milky turbid liquid, and performing transmission electron microscope characterization. Fig. 17 is a TEM image of the preparation of carbon hollow carbon nanospheres with the substitution of meta-acid with 3-aminobenzenesulfonic acid.

Example 17

At room temperature, 0.02g of AOT is taken and completely dissolved in 10mL of water, then 0.01g of TMB is added and vigorously stirred for more than 6 hours to form a uniform light white system, which is marked as solution A; 0.252g (2 mmol) of melamine and 0.104g (0.6 mmol) of 4-aminobenzenesulfonic acid were dissolved in 90mL of water at 30℃and designated as solution B. Transfer solution A completely to solution B and hold at 30℃and 300rpm stirring rate for at least 1h, then add 3mL of formaldehyde solution and continue the reaction under the above conditions, begin to appear clear white turbidity after 30s and stop the reaction after 180 min. And centrifuging, washing, drying and carbonizing the obtained milky turbid liquid, and performing transmission electron microscope characterization. Fig. 18 is a TEM image of the preparation of carbon hollow carbon nanospheres with the replacement of meta-acid with 3-aminobenzenesulfonic acid.

Example 18

At room temperature, 0.02g of AOT is taken and completely dissolved in 10mL of water, then 0.01g of TMB is added and vigorously stirred for more than 6 hours to form a uniform light white system, which is marked as solution A; 0.252g (2 mmol) of melamine and 0.09g (0.6 mmol) of 2, 3-diaminobenzoic acid were dissolved in 90mL of water at 30℃and designated as solution B. Transfer solution A completely to solution B and hold at 30℃and 300rpm stirring rate for at least 1h, then add 3mL of formaldehyde solution and continue the reaction under the above conditions, begin to appear clear white turbidity after 30s and stop the reaction after 180 min. And centrifuging, washing, drying and carbonizing the obtained milky turbid liquid, and performing transmission electron microscope characterization. Fig. 19 is a TEM image of the preparation of carbon hollow carbon nanospheres with the substitution of meta-acid with 2, 3-diaminobenzoic acid.

Example 19

At room temperature, 0.02g of AOT is taken and completely dissolved in 10mL of water, then 0.01g of TMB is added and vigorously stirred for more than 6 hours to form a uniform light white system, which is marked as solution A; 0.252g (2 mmol) of melamine and 0.09g (0.6 mmol) of 3, 5-diaminobenzoic acid (3, 5-diaminobenzoic acid) were dissolved in 90mL of water at 30℃and designated as solution B. Transfer solution A completely to solution B and hold at 30℃and 300rpm stirring rate for at least 1h, then add 3mL of formaldehyde solution and continue the reaction under the above conditions, begin to appear clear white turbidity after 30s and stop the reaction after 180 min. And centrifuging, washing, drying and carbonizing the obtained milky turbid liquid, and performing transmission electron microscope characterization. FIG. 20 is a TEM image of the preparation of carbon hollow carbon nanospheres with the substitution of meta-acid with 3, 5-diaminobenzoic acid.

Example 20

At room temperature, 0.02g of AOT is taken and completely dissolved in 10mL of water, then 0.01g of TMB is added and vigorously stirred for more than 6 hours to form a uniform light white system, and the uniform light white system is marked as solution A; 0.252g (2 mmol) of melamine and 0.082g (0.6 mmol) of 2-aminobenzoic acid were dissolved in 90mL of water at 30℃and designated as solution B. Transfer solution A completely to solution B and hold at 30℃and 300rpm stirring rate for at least 1h, then add 3mL of formaldehyde solution and continue the reaction under the above conditions, begin to appear clear white turbidity after 30s and stop the reaction after 180 min. And centrifuging, washing, drying and carbonizing the obtained milky turbid liquid, and performing transmission electron microscope characterization. Fig. 21 is a TEM image of the preparation of carbon hollow carbon nanospheres with the substitution of meta-acid with 2-aminobenzoic acid.

Example 21

At room temperature, 0.02g of AOT is taken and completely dissolved in 10mL of water, then 0.01g of TMB is added and vigorously stirred for more than 6 hours to form a uniform light white system, which is marked as solution A; 0.252g (2 mmol) of melamine and 0.082g (0.6 mmol) of 3-aminobenzoic acid were dissolved in 90mL of water at 30℃and designated as solution B. Transfer solution A completely to solution B and hold at 30℃and 300rpm stirring rate for at least 1h, then add 3mL of formaldehyde solution and continue the reaction under the above conditions, begin to appear clear white turbidity after 30s and stop the reaction after 180 min. And centrifuging, washing, drying and carbonizing the obtained milky turbid liquid, and performing transmission electron microscope characterization. Fig. 22 is a TEM image of the preparation of carbon hollow carbon nanospheres with the replacement of meta-acid with 3-aminobenzoic acid.

Example 22

At room temperature, 0.02g of AOT is taken and completely dissolved in 10mL of water, then 0.01g of TMB is added and vigorously stirred for more than 6 hours to form a uniform light white system, which is marked as solution A; 0.252g (2 mmol) of melamine and 0.082g (0.6 mmol) of 4-aminobenzoic acid were dissolved in 90mL of water at 30℃and designated as solution B. Transfer solution A completely to solution B and hold at 30℃and 300rpm stirring rate for at least 1h, then add 3mL of formaldehyde solution and continue the reaction under the above conditions, begin to appear clear white turbidity after 30s and stop the reaction after 180 min. And centrifuging, washing, drying and carbonizing the obtained milky turbid liquid, and performing transmission electron microscope characterization. Fig. 23 is a TEM image of hollow carbon nanospheres prepared by replacing meta-acid with 4-aminobenzoic acid.

Example 23

At room temperature, 0.02g of AOT is taken and completely dissolved in 10mL of water, then 0.01g of TMB is added and vigorously stirred for more than 6 hours to form a uniform light white system, which is marked as solution A; 0.252g (2 mmol) of melamine and 0.113g (0.6 mmol) of isophthalic acid are dissolved in 90mL of water at 30℃and are designated as solution B. Transfer solution A completely to solution B and hold at 30℃and 300rpm stirring rate for at least 1h, then add 3mL of acetaldehyde solution and continue the reaction under the above conditions, begin to appear clear white turbidity after 30s and stop the reaction after 180 min. And centrifuging, washing, drying and carbonizing the obtained milky turbid liquid, and performing transmission electron microscope characterization. Fig. 24 is a TEM image of hollow carbon nanospheres prepared with acetaldehyde as the fatty aldehyde.

Example 24

At room temperature, 0.02g of AOT is taken and completely dissolved in 10mL of water, then 0.01g of TMB is added and vigorously stirred for more than 6 hours to form a uniform light white system, which is marked as solution A; 0.252g (2 mmol) of melamine and 0.113g (0.6 mmol) of isophthalic acid are dissolved in 90mL of water at 30℃and are designated as solution B. Transfer solution A completely to solution B and hold at 30℃and 300rpm stirring rate for at least 1h, then add 1.5mL glyoxal solution and continue the reaction under the above conditions, begin to appear visibly white turbidity after 30s and stop the reaction after 180 min. And centrifuging, washing, drying and carbonizing the obtained milky turbid liquid, and performing transmission electron microscope characterization. Fig. 25 is a TEM image of hollow carbon nanospheres prepared with glyoxal as the fatty aldehyde.

Example 25

At room temperature, 0.02g of AOT is taken and completely dissolved in 10mL of water, then 0.01g of TMB is added and vigorously stirred for more than 6 hours to form a uniform light white system, which is marked as solution A; 0.252g (2 mmol) of melamine and 0.113g (0.6 mmol) of isophthalic acid are dissolved in 90mL of water at 30℃and are designated as solution B. Transfer solution A completely to solution B and hold at 30℃and 300rpm stirring rate for at least 1h, then add 1.5mL glutaraldehyde solution and continue the reaction under the above conditions, begin to appear visibly white turbidity after 30s and stop the reaction after 180 min. And centrifuging, washing, drying and carbonizing the obtained milky turbid liquid, and performing transmission electron microscope characterization. Fig. 26 is a TEM image of hollow carbon nanospheres prepared with glutaraldehyde as the fatty aldehyde.

Example 26

At room temperature, 0.02g of AOT is taken and completely dissolved in 10mL of water, then 0.01g of TMB is added and vigorously stirred for more than 6 hours to form a uniform light white system, which is marked as solution A; 0.252g (2 mmol) of melamine and 0.113g (0.6 mmol) of isophthalic acid are dissolved in 90mL of water at 30℃and are designated as solution B. Transfer solution A completely to solution B and hold at 30℃and 300rpm stirring rate for at least 1h, then add 1.5mL of glyoxal solution and continue the reaction under the above conditions, begin to appear visibly white turbidity after 30s and stop the reaction after 180 min. And centrifuging, washing, drying and carbonizing the obtained milky turbid liquid, and performing transmission electron microscope characterization. Fig. 27 is a TEM image of hollow carbon nanospheres prepared with glyoxal as the fatty aldehyde.

Example 27

At room temperature, 0.5mL of dioctyl sodium sulfosuccinate (straight-chain) solution is taken and completely dissolved in 10mL of water, then 0.02g of TMB is added and vigorously stirred for more than 6 hours to form a uniform light white system, which is marked as solution A; 0.252g (2 mmol) of melamine and 0.113g (0.6 mmol) of isophthalic acid are dissolved in 90mL of water at 30℃and are designated as solution B. Transfer solution A completely to solution B and hold at 30℃and 300rpm stirring rate for at least 1h, then add 3mL of formaldehyde solution and continue the reaction under the above conditions, begin to appear clear white turbidity after 30s and stop the reaction after 180 min. And (3) centrifuging, washing, drying and carbonizing the obtained milky turbid liquid at 800 ℃ and then carrying out transmission electron microscope characterization. Fig. 28 is a TEM image of hollow carbon nanoparticles prepared with dioctyl sodium sulfosuccinate (straight chain) as a surfactant.

Example 28

At room temperature, 0.04g of SDBS is taken and completely dissolved in 10mL of water, then 0.02g of TMB is added and vigorously stirred for more than 6 hours to form a uniform light white system, and the uniform light white system is marked as solution A; 0.252g (2 mmol) of melamine and 0.150g (0.6 mmol) of isophthalic acid are dissolved in 90mL of water at 30℃and are designated as solution B. Transfer solution A completely to solution B and hold at 30℃and 300rpm stirring rate for at least 1h, then add 1.5mL of glyoxal solution and continue the reaction under the above conditions, begin to appear visibly white turbidity after 30s and stop the reaction after 180 min. And (3) centrifuging, washing, drying and carbonizing the obtained milky turbid liquid at 800 ℃ and then carrying out transmission electron microscope characterization. Fig. 29 is a TEM image of hollow carbon nanoparticles prepared with SDBS as a surfactant.

Example 29

At room temperature, 0.02g of AOT was taken and dissolved completely in 10mL of water, designated solution A; 0.252g (2 mmol) of melamine and 0.113g (0.6 mmol) of isophthalic acid are dissolved in 90mL of water at 30℃and are designated as solution B. Transfer solution A completely to solution B and hold at 30℃and 0rpm stirring rate for at least 1h, then add 3mL of formaldehyde solution and continue the reaction under the above conditions, begin to appear clear white turbidity after 30s and stop the reaction after 180 min. And (3) centrifuging, washing, drying and carbonizing the obtained milky turbid liquid, and then carrying out X-ray photoelectron spectroscopy characterization. FIG. 30 is an X-ray spectrum analysis chart of the hollow carbon nanospheres with the heteroatom-doped core-shell structures prepared by the invention. As a result, the heteroatom doped hollow carbon nanospheres with the core-shell structure have excellent heteroatom doping characteristics.

Example 30

At room temperature, 0.02g of AOT is taken and completely dissolved in 10mL of water, then 0.01g of TMB is added and vigorously stirred for more than 6 hours to form a uniform light white system, which is marked as solution A; 0.252g (2 mmol) of melamine and 0.113g (0.6 mmol) of isophthalic acid are dissolved in 90mL of water at 30℃and are designated as solution B. Transfer solution A completely to solution B and hold at 30℃and 0rpm stirring rate for at least 1h, then add 3mL of formaldehyde solution and continue the reaction under the above conditions, begin to appear clear white turbidity after 30s and stop the reaction after 180 min. And (3) centrifuging, washing, drying and carbonizing the obtained milky turbid liquid, and then carrying out X-ray photoelectron spectroscopy characterization. FIG. 31 is an X-ray spectrum analysis chart of the hollow carbon nanospheres of the heteroatom doped multi-shell structure of the present invention. The result further proves that the heteroatom doped multi-shell structure hollow carbon nanospheres have excellent heteroatom doping characteristics.

Example 31

At room temperature, 0.02g of AOT was taken and dissolved completely in 10mL of water, designated solution A; 0.252g (2 mmol) of melamine and 0.113g (0.6 mmol) of isophthalic acid are dissolved in 90mL of water at 30℃and are designated as solution B. Transfer solution A completely to solution B and hold at 30℃and 300rpm stirring rate for at least 1h, then add 3mL of solution A and continue the reaction under the above conditions, begin to appear clear white turbidity after 30s and stop the reaction after 180 min. And (3) centrifuging, washing, drying and carbonizing the obtained milky turbid liquid, taking more than 100mg of sample, degassing for 6 hours at 200 ℃, and then carrying out nitrogen adsorption and desorption experiments at-196 ℃ to obtain corresponding nitrogen adsorption and desorption isotherms and BJ H pore diameter distribution diagrams. FIG. 32 is a graph showing the nitrogen adsorption-desorption curves and pore size distribution of the heteroatom-doped core-shell carbon nanospheres prepared in accordance with the present invention. From the graph a, the medium pressure section in the nitrogen adsorption-desorption curve of the prepared material has obvious hysteresis, which indicates that the material has a mesoporous structure. From figure b it can be seen that there are plentiful mesopores of different sizes in the material.

Example 32

At room temperature, 0.02g of AOT is taken and fully dissolved in 10mL of water, and then 0.01g of 1,3, 5-triethylbenzene is added and vigorously stirred for more than 6 hours to obtain a solution A; 0.252g (2 mmol) of melamine and 0.113g (0.6 mmol) of isophthalic acid are dissolved in 90mL of water at 30℃and are designated as solution B. Transfer solution A completely to solution B and hold at 30℃and 300rpm stirring rate for at least 1h, then add 3mL of solution A and continue the reaction under the above conditions, begin to appear clear white turbidity after 30s and stop the reaction after 180 min. And (3) centrifuging, washing, drying and carbonizing the obtained milky turbid liquid, taking more than 100mg of sample, degassing for 6 hours at 200 ℃, and then carrying out nitrogen adsorption and desorption experiments at-196 ℃ to obtain corresponding nitrogen adsorption and desorption isotherms and BJ H pore diameter distribution diagrams. FIG. 33 is a graph showing the nitrogen adsorption and desorption curves and pore size distribution of the heteroatom-doped single-shell hollow carbon nanospheres prepared in accordance with the present invention. From the graph a, the medium pressure section in the nitrogen adsorption-desorption curve of the prepared material has obvious hysteresis, which indicates that the material has a mesoporous structure. From figure b it can be seen that there are plentiful mesopores of different sizes in the material.

Example 33

At room temperature, 0.02g of AOT is taken and completely dissolved in 10mL of water, then 0.01g of TMB is added and vigorously stirred for more than 6 hours, and the mixture is recorded as solution A; 0.252g (2 mmol) of melamine and 0.113g (0.6 mmol) of isophthalic acid are dissolved in 90mL of water at 30℃and are designated as solution B. Transfer solution A completely to solution B and hold at 30℃and 300rpm stirring rate for at least 1h, then add 3mL of solution A and continue the reaction under the above conditions, begin to appear clear white turbidity after 30s and stop the reaction after 180 min. And (3) centrifuging, washing, drying and carbonizing the obtained milky turbid liquid, taking more than 100mg of sample, degassing for 6 hours at 200 ℃, and then carrying out nitrogen adsorption and desorption experiments at-196 ℃ to obtain corresponding nitrogen adsorption and desorption isotherms and BJ H pore diameter distribution diagrams. FIG. 34 is a graph showing the nitrogen adsorption and desorption curves and pore size distribution of the heteroatom-doped multi-shell hollow carbon nanospheres prepared in accordance with the present invention. From the graph a, the medium pressure section in the nitrogen adsorption-desorption curve of the prepared material has obvious hysteresis, which indicates that the material has a mesoporous structure. From figure b it can be seen that there are plentiful mesopores of different sizes in the material.

Example 34

Taking melamine, meta-acid, formaldehyde and AOT/TMB as examples, the carbonization procedure of the obtained polymer is 1 ℃/min, the temperature is raised from 100 ℃ to 150 ℃ to 350 ℃ and kept for 120min to 180min, then the temperature is raised to the target temperature (500, 600, 700, 800, 1000 ℃ and the like) at 3 ℃/min and kept for 120min to 180min, and then the temperature is naturally lowered to the room temperature; the carbonization temperatures not specifically indicated in the above examples were all 800℃and the carbonization procedure was established according to the results of thermogravimetric analysis of the heteroatom-doped biopolymer material of FIG. 35. In particular, the thermogravimetric analysis curve of the polymer can be divided into three sections, a relatively slow weight loss before 300 ℃, a fast weight loss between 300 and 400 ℃ and a further weight loss above 400 ℃. Thus, 350 ℃ is taken as the critical temperature for slow temperature rise to keep the unstable species in the polymer sufficiently decomposed.

Example 35

At room temperature, 0.02g of AOT was taken and dissolved completely in 10mL of water, followed by vigorous stirring with 0.01g of TMB for more than 6 hours to form a uniform pale white system, and a digital photograph was taken. FIG. 36 is a physical diagram showing the state of an emulsion after the template agent and the auxiliary agent are mixed at 30 ℃.

Example 36

At room temperature, 0.02g of AOT is taken and completely dissolved in 10mL of water, then 0.01g of TMB is added and vigorously stirred for more than 6 hours to form a uniform light white system, which is marked as solution A; 0.252g (2 mmol) of melamine was dissolved in 90mL of water at 30℃and noted as solution B. After transferring solution A completely to solution B and maintaining at 30℃and 300rpm stirring rate for at least 1 hour, taking digital photographs, as shown in FIG. 37, it was found that the system remained clear and transparent after mixing solution A with solution B. Further validation illustrates the effect of aromatic amine-acids on the construction of adaptive templates.

Example 37

At room temperature, 0.02g of AOT is taken and completely dissolved in 10mL of water, then 0.01g of TMB is added and vigorously stirred for more than 6 hours to form a uniform light white system, which is marked as solution A; 0.113g (0.6 mmol) of the isophthalic acid was dissolved in 90mL of water at 30℃and designated as solution B. After transferring solution A completely to solution B and maintaining at 30℃and 300rpm stirring rate for at least 1 hour, taking digital photographs, it was found that the entire system remained clear and transparent after mixing solution A with solution B, as shown in FIG. 38. The result shows that the construction of the self-adaptive template in the system is formed by protonating the amino group of melamine under the condition that the system is regulated to be in an acidic state based on aromatic amine-acid.

Example 38

At room temperature, 0.02g of AOT is taken and completely dissolved in 10mL of water, and then 0.01g, 0.02g, 0.04g and 0.06g of TMB are added and vigorously stirred for more than 6 hours to form a uniform light white system, which is marked as solution A; 0.252g (2 mmol) of melamine and 0.113g (0.6 mmol) of isophthalic acid are dissolved in 90mL of water at 30℃and are designated as solution B. The liquid A was completely transferred to the liquid B and maintained at 30℃and 300rpm stirring rate for 1 hour, and a digital photograph was taken of the system, and as shown in FIG. 39, it was found that the system instantaneously turned pale white during the transfer of the liquid A to the liquid B, and the system tended to stabilize and become completely pale milky white system with the complete transfer of A and the change in the holding time, indicating the formation of the novel surfactant and the formation of the template.

Example 39

At room temperature, 0.02g of AOT is taken and completely dissolved in 10mL of water, then 0.01g of TMB is added and vigorously stirred for more than 6 hours to form a uniform light white system, which is marked as solution A; 0.252g (2 mmol) of melamine and 0.113g (0.6 mmol) of isophthalic acid are dissolved in 90mL of water at 30℃and are designated as solution B. The solution A was completely transferred to the solution B and maintained at 30℃and a stirring rate of 300rpm for at least 1 hour, followed by addition of 3mL of formaldehyde solution and continued reaction under the above conditions, starting to appear clear white turbidity after 30 seconds, and ending the reaction after 180 minutes, and the obtained white emulsion was subjected to digital photograph taking as shown in FIG. 40.

Many possible variations and modifications of the disclosed technology can be made by anyone skilled in the art without departing from the scope of the technology, or the technology can be modified to be equivalent. Therefore, any simple modification, equivalent variation and modification of the above embodiments according to the technical substance of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. The preparation method of the heteroatom doped hollow carbon nanospheres is characterized by comprising the following steps of: the method comprises the steps of (1) keeping a system acidic by taking aromatic amine-acid as a pH regulator, taking melamine as a raw material, taking an anionic surfactant as a template agent, enabling amino groups of the melamine to be protonated and to interact with the anionic surfactant as organic counter ions to form an anionic-cationic surfactant, and constructing and forming a self-adaptive vesicle template; introducing fatty aldehyde to form a Schiff base intermediate, adding melamine to an imine bond of the Schiff base intermediate, and performing cross-linking polymerization to obtain a polymer nanosphere; carbonizing to obtain hollow carbon nanospheres;

The anionic surfactant is one of sodium bis (2-ethylhexyl) sulfosuccinate, straight-chain dioctyl sodium sulfosuccinate and sodium dodecyl benzene sulfonate; when the core-shell hollow carbon spheres are prepared, the concentration is more than 0 and less than 1 mmol/L; when the multi-shell structure is prepared, the concentration is more than 0 and less than the critical micelle concentration;

the method for constructing the adaptive vesicle template comprises the following steps:

2. The method for preparing the heteroatom doped hollow carbon nanospheres according to claim 1, wherein the template auxiliary agent is one of 1,3, 5-trimethylbenzene, 1,3, 5-triethylbenzene and 1,3, 5-triisopropylbenzene; the template auxiliary agent dosage is 0.5-5 times of the template agent mass.

3. The method for preparing the heteroatom doped hollow carbon nanospheres according to claim 1, wherein the fatty aldehyde is one of formaldehyde, acetaldehyde, glyoxal, glutaraldehyde and glyoxal; the fatty aldehyde amount is more than 1 equivalent of melamine.

4. The method for preparing the heteroatom doped hollow carbon nanospheres according to claim 1, wherein the carbonization condition is that the carbonization temperature is 400-1000 ℃ and the carbonization time is 30-180 min under the inert gas atmosphere.

5. The method of preparing heteroatom doped hollow carbon nanospheres according to claim 4, wherein the inert gas comprises nitrogen or argon.

6. The method for preparing the heteroatom doped hollow carbon nanospheres according to claim 1, wherein the aromatic amine-acid is one of meta acid, 2, 5-diaminobenzenesulfonic acid, 2-aminobenzenesulfonic acid, 3-aminobenzenesulfonic acid, 4-aminobenzenesulfonic acid, 2, 3-diaminobenzoic acid, 3, 5-diaminobenzoic acid, 3, 4-diaminobenzoic acid, 2, 5-diaminobenzoic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid; the aromatic amine-acid amount is 5% -50% of the melamine molar amount.

7. The method for preparing the heteroatom doped hollow carbon nanospheres according to claim 1, wherein the polymer nanospheres are subjected to solid-liquid separation and then are subjected to drying treatment; the solid-liquid separation method comprises suction filtration and centrifugation; the drying method comprises freeze drying, room temperature drying or heat drying.

8. A heteroatom-doped hollow carbon nanosphere prepared by the method of preparing a heteroatom-doped hollow carbon nanosphere of any one of claims 1-7.