Nitrogen atom-doped mesoporous nanospheres and a method for preparing the same

Abstract

The application relates to a nitrogen atom doped mesoporous nanosphere and a preparation method thereof, and belongs to the technical field of new nanomaterials. A kind of surfactant is used as co-template agent, and nanomicelles are constructed through the synergistic effect between the two kinds of surfactants; melamine and aromatic amine-acid are used as main raw materials, and a fatty aldehyde is introduced to form a Schiff base intermediate between the fatty aldehyde and the aromatic amine-acid; after the melamine is added to the Schiff base intermediate, the melamine is crosslinked into a melamine-based oligomer; the nanomicelles and the oligomer are synergistically co-assembled to form a composite polymer nanosphere; after separation and washing treatment, a nitrogen atom doped mesoporous polymer nanosphere is obtained; and after high-temperature pyrolysis treatment in an inert atmosphere, a nitrogen atom doped mesoporous carbon nanosphere is obtained. The method has the advantages of low cost, simple operation, controllable process, mild process conditions, realization of the construction of the mesoporous structure of the target product, facilitation of large-scale commercial production and application, and promotion of the practical application process of the nitrogen atom doped mesoporous nanosphere.

Description

Technical Field

[0001] This invention belongs to the field of nanomaterials technology, specifically relating to a nitrogen-doped mesoporous polymer nanosphere, a mesoporous carbon nanosphere, and a method for preparing the same. Background Technology

[0002] Nitrogen-doped mesoporous carbon materials have great application potential in popular fields such as adsorption and separation, drug release, and energy storage and conversion. In particular, the spherical morphology and small particle size can shorten the mass transfer path, reduce the viscosity effect, and enhance the application performance of the materials.

[0003] Currently, significant efforts have been invested in the in-situ synthesis of nitrogen-doped mesoporous carbon materials. Conventional soft-templating and hard-templating methods produce nitrogen-doped mesoporous carbon materials with relatively small pore sizes (<3 nm), which limits their application range and performance to some extent. Furthermore, the precursors commonly used in soft-templating methods are often aminophenol, dopamine, and copolymers of nitrogen-rich organic monomers with phenol (1,3-benzenediol), inevitably facing problems such as low nitrogen content, high cost, and complex operation. Therefore, from the perspective of materials synthesis, actively promoting low-cost, simple, and efficient synthesis strategies to achieve the preparation of nitrogen-doped mesoporous carbon materials with high nitrogen content and large pore sizes remains of great significance and challenge.

[0004] Melamine, rich in nitrogen and inexpensive, has long been a research focus in nitrogen-doped mesoporous carbon materials. Existing reports on the synthesis of melamine-based large-sized mesoporous carbon materials often employ hard template methods using SiO2 spheres of varying sizes, requiring complex SiO2 sphere removal processes. Soft template methods typically use hydroxymethylated melamine as a precursor and high-molecular-weight block copolymers (PS-b-PEO / PS-b-PAA) as template agents, achieving controllable preparation of large-sized mesoporous nitrogen-doped carbon materials with uniform and tunable pore sizes by adjusting the PS segment length. However, the related block copolymer template preparation processes are complex, cumbersome, and costly. Furthermore, the corresponding nitrogen-doped mesoporous carbon materials usually exist in the form of films or irregular micron-sized particles, and the relatively long diffusion paths limit the material's mass transfer capabilities to some extent. Therefore, designing and synthesizing melamine-based nitrogen-doped mesoporous carbon nanospheres at the nanoscale can expose more surface active sites, enhancing the material's application performance. Summary of the Invention

[0005] The present invention aims to provide an efficient and economical method for preparing nitrogen-doped mesoporous nanospheres, thereby solving the problems of harsh conditions, high costs and complex operations in the existing technology.

[0006] To achieve the above objectives, this invention provides a method for preparing nitrogen-doped mesoporous nanospheres. The method uses a dual-surfactant mixture of anionic and nonionic surfactants as co-templating agents to construct nanomicelles through the synergistic effect between the two surfactants. Melamine and aromatic amine-acids are used as main raw materials. After introducing aliphatic aldehydes, they form a Schiff base intermediate with the aromatic amine-acid. Melamine then adds to this Schiff base intermediate, crosslinking it to form melamine-based oligomers. The nanomicelles and oligomers synergistically co-assemble to form composite polymer nanospheres. After separation, washing, drying, and calcination under an inert atmosphere, nitrogen-doped mesoporous nanospheres are obtained.

[0007] The preparation method specifically includes the following steps:

[0008] S1. Under conditions of 0–30°C, one of the anionic surfactant and the nonionic surfactant is dissolved in water and stirred vigorously for at least 3 hours or ultrasonically assisted stirring for at least 30 minutes to form a composite surfactant solution; the mass ratio of the nonionic surfactant to the anionic surfactant is not less than 3.

[0009] S2. The composite surfactant solution obtained in S1 is added to the precursor solution to obtain a mixed solution. The mixed solution is stirred for at least 1 hour to form a stable micelle system. The concentration of melamine in the mixed solution is between 0.1 mM and 30 mM, with the most preferred concentration being 20 mM. The molar ratio of aromatic amine-acid to melamine is 1:(5-8). The concentration of anionic surfactant in the mixed solution is between 0.1 mM and 3.0 mM, with the most preferred concentration being 0.3 mM.

[0010] S3. Add fatty aldehyde to the system of S2 and obtain an emulsion suspension under stirring; wherein the amount of fatty aldehyde is 1 equivalent or more of melamine;

[0011] S4. The emulsion suspension was separated, washed, and dried, and then calcined under an inert atmosphere to obtain nitrogen-doped mesoporous nanospheres.

[0012] The anionic surfactant is one of sodium oleate, sodium stearate, sodium laurate, sodium dodecyl sulfonate, and sodium dodecylbenzene sulfonate; the nonionic surfactant is one of F127 and P123.

[0013] Fatty aldehydes are one of formaldehyde, acetaldehyde, glyoxal, glutaraldehyde, and adipaldehyde.

[0014] The aromatic amine-acid is one of 3,5-diaminobenzoic acid, 2,3-diaminobenzoic acid, 3,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, 2,4-diaminobenzenesulfonic acid, 2,5-diaminobenzenesulfonic acid, 2-aminobenzenesulfonic acid, 3-aminobenzenesulfonic acid, and 4-aminobenzenesulfonic acid.

[0015] A method for preparing nitrogen-doped mesoporous carbon nanospheres, wherein the calcination temperature is 300℃~1000℃; the heating rate of the heating program is 1℃ / min or 2℃ / min, and the calcination time is 30~180min.

[0016] A nitrogen-doped mesoporous nanosphere was prepared using the method described above.

[0017] The nitrogen-doped mesoporous nanospheres have a particle size of 50 nm to 1 m and a specific surface area of ​​300 to 600 m². 2 / g, total pore volume is 0.6–2.5 cm³ 3 / g; mesopore volume is 0.40~2.0cm³ 3 / g, with mesopore diameters of 5–40 nm.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] 1. The method described in this invention adopts a novel synthetic route. Under mild conditions, the reaction can be terminated as needed in just 5 to 180 minutes, and the operation and process are simple. It avoids the harsh and lengthy preparation conditions in the preparation of traditional melamine resin-based nitrogen-doped mesoporous materials and melamine-based nitrogen-doped mesoporous materials.

[0020] 2. Compared with the hard template method commonly used in the preparation of nitrogen-doped mesoporous materials and melamine-based nitrogen-doped mesoporous materials, the method of the present invention has the advantages of simple operation, environmental friendliness and process controllability.

[0021] 3. Compared with the single surfactant (templating agent) soft template method commonly used in the preparation of nitrogen-doped mesoporous materials, the method of the present invention can significantly reduce the amount of expensive nonionic surfactants such as F127 and P123 used, reduce raw material costs, and improve economic efficiency.

[0022] 4. Compared with nitrogen-doped mesoporous materials prepared by conventional soft and hard template methods, the method of the present invention has a large pore size and a small particle size, which improves the mass transfer capacity and application performance of the material. Compared with the raw materials such as dopamine commonly used to prepare relatively large-pore mesoporous materials, the raw materials used in the method of the present invention are low in cost, economically efficient, and conducive to large-scale production. Attached Figure Description

[0023] Figure 1 This is a SEM image of nitrogen-doped mesoporous polymer nanospheres prepared by the method of this invention.

[0024] Figure 2 This is a TEM image of nitrogen-doped mesoporous polymer nanospheres prepared by the method of this invention.

[0025] Figure 3 This is a TEM image of nitrogen-doped nanospheres prepared by the method of the present invention without the use of a template agent.

[0026] Figure 4 This is a TEM image of nitrogen-doped polymer nanospheres prepared by the method of the present invention using sodium oleate alone.

[0027] Figure 5 This is a TEM image of nitrogen-doped polymer nanospheres prepared by the method of the present invention using P123 alone.

[0028] Figure 6 These are TEM images of nitrogen-doped mesoporous polymer nanospheres prepared by the method of this invention under different mass ratios of SO / P123.

[0029] Figure 7 These are TEM images of nitrogen-doped mesoporous polymer nanospheres prepared by the method of this invention under different composite surfactant conditions.

[0030] Figure 8 These are TEM images of nitrogen-doped mesoporous polymer nanospheres prepared by the method of this invention under different amounts of 3,5-diaminobenzoic acid.

[0031] Figure 9 This is a TEM image of nitrogen-doped mesoporous polymer nanospheres prepared by the method of this invention after being magnified 50 times.

[0032] Figure 10 This is a TEM image of heteroatom-doped mesoporous polymer nanospheres prepared by the method of the present invention, in which 2,3-diaminobenzoic acid is involved in the reaction.

[0033] Figure 11 This is a TEM image of heteroatom-doped mesoporous polymer nanospheres prepared by the method of the present invention, in which 3,4-diaminobenzoic acid is involved in the reaction.

[0034] Figure 12 This is a TEM image of nitrogen-doped mesoporous polymer nanospheres prepared by the method of the present invention, in which 2-aminobenzoic acid participates in the reaction.

[0035] Figure 13 This is a TEM image of nitrogen-doped mesoporous polymer nanospheres prepared by the method of the present invention, in which 3-aminobenzoic acid participates in the reaction.

[0036] Figure 14 This is a TEM image of nitrogen-doped mesoporous polymer nanospheres prepared by the method of the present invention, in which 4-aminobenzoic acid participates in the reaction.

[0037] Figure 15 This is a TEM image of nitrogen-doped mesoporous polymer nanospheres prepared by the method of the present invention in the presence of 2,4-diaminobenzenesulfonic acid.

[0038] Figure 16 This is a TEM image of nitrogen-doped mesoporous polymer nanospheres prepared by the method of the present invention, which involves the reaction of 2,5-diaminobenzenesulfonic acid.

[0039] Figure 17 This is a TEM image of nitrogen-doped mesoporous polymer nanospheres prepared by the method of the present invention, in which 2-aminobenzenesulfonic acid is involved in the reaction.

[0040] Figure 18 This is a TEM image of nitrogen-doped mesoporous polymer nanospheres prepared by the method of the present invention, in which 3-aminobenzenesulfonic acid is involved in the reaction.

[0041] Figure 19 This is a TEM image of nitrogen-doped mesoporous polymer nanospheres prepared by the method of the present invention, which involves the reaction of 4-aminobenzenesulfonic acid.

[0042] Figure 20 This is a TEM image of nitrogen-doped mesoporous polymer nanospheres prepared by the method of the present invention using acetaldehyde in a reaction.

[0043] Figure 21 This is a TEM image of nitrogen-doped mesoporous polymer nanospheres prepared by glyoxal reaction according to the method of this invention.

[0044] Figure 22 This is a TEM image of nitrogen-doped mesoporous polymer nanospheres prepared by the method of the present invention, involving glutaraldehyde in the reaction.

[0045] Figure 23 This is a TEM image of nitrogen-doped mesoporous polymer nanospheres prepared by the method of the present invention, involving the reaction of adipaldehyde.

[0046] Figure 24 This is a TGA image of nitrogen-doped mesoporous polymer nanospheres prepared by the method of this invention.

[0047] Figure 25 This is a SEM image of nitrogen-doped mesoporous carbon nanospheres prepared by the method of this invention.

[0048] Figure 26 This is a TEM image of nitrogen-doped mesoporous carbon nanospheres prepared by the method of this invention.

[0049] Figure 27This is a physical structural characterization of the nitrogen-doped mesoporous carbon nanospheres prepared by the method of this invention.

[0050] Figure 28 XPS characterization of nitrogen-doped mesoporous carbon nanospheres prepared by the method of this invention.

[0051] Figure 29 These are the XRD and Raman spectra of nitrogen-doped mesoporous carbon nanospheres prepared by the method of this invention.

[0052] Figure 30 This is a graph showing the carbon dioxide adsorption performance of nitrogen-doped mesoporous carbon nanospheres prepared by the method of this invention.

[0053] Figure 31 This is a performance diagram of a supercapacitor made from nitrogen-doped mesoporous carbon nanospheres prepared by the method of this invention.

[0054] Figure 32 This is a performance diagram of nitrogen-doped mesoporous carbon nanospheres prepared by the method of this invention as a negative electrode for lithium-ion batteries. Detailed Implementation

[0055] The present invention will be further described below with reference to specific embodiments, but this does not limit the present invention in any way.

[0056] Unless otherwise specified, the instruments, reagents, and materials used in the following embodiments are all conventional instruments, reagents, and materials already available in the prior art and can be obtained through legitimate commercial channels. Unless otherwise specified, the experimental methods and detection methods used in the following embodiments are all conventional experimental methods and detection methods already available in the prior art.

[0057] This invention provides nitrogen-doped mesoporous nanospheres and their preparation method, comprising the following steps: constructing nanomicelles under mild conditions (0–30°C) using the synergistic effect of composite surfactants; using melamine and aromatic amine-acids as main raw materials, and combining anionic surfactants such as sodium oleate and nonionic surfactants such as P123 as dual template agents to construct nanomicelles. In the system, aliphatic aldehydes preferentially form Schiff base intermediates with the used aromatic amine-acids, followed by melamine addition to the Schiff base and crosslinking to form melamine-based oligomers; the melamine-based oligomers and nanomicelles interact based on Coulomb forces and hydrogen bonds, and co-assemble into composite polymer nanospheres; after separation, washing, and other treatments, nitrogen-doped mesoporous polymer nanospheres are obtained; the above mesoporous polymer nanospheres are carbonized under an inert atmosphere to obtain nitrogen-doped mesoporous carbon nanospheres with high specific surface area, high porosity, high nitrogen atom doping, and small particle size.

[0058] Specifically, the steps include:

[0059] (1) Under the conditions of 0 to 30°C, anionic surfactant and nonionic surfactant are dissolved in water at a certain mass / molar ratio for later use. The anionic surfactant is one of sodium oleate, sodium stearate, sodium laurate, sodium dodecyl sulfonate, and sodium dodecylbenzene sulfonate; the nonionic surfactant is one of F127 and P123.

[0060] (2) Melamine and aromatic amine-acid are completely dissolved in water at 0-30℃ to form a precursor solution;

[0061] (3) Introduce the solution prepared in step (1) into the precursor solution in step (2) and stabilize it for at least 1 hour with stirring to form a stable system;

[0062] (4) Add fatty aldehyde to the system in step (3) and react at a stirring rate of 0-1500 rpm for more than 5 min to obtain an emulsion suspension; the amount of fatty aldehyde is 1 equivalent or more of melamine; the fatty aldehyde is one of formaldehyde, acetaldehyde, glyoxal, glutaraldehyde, and adipaldehyde.

[0063] (5) The suspension obtained in step (4) is subjected to solid-liquid separation and washing; the resulting solid is dried to obtain nitrogen-doped mesoporous polymer nanospheres.

[0064] (6) The product obtained in step (5) is subjected to high-temperature pyrolysis treatment, i.e. carbonization treatment, under an inert atmosphere to obtain nitrogen atom-doped mesoporous carbon nanospheres.

[0065] The optimal temperature for step (1) is 30°C, and the mixing time of the anionic surfactant and the nonionic surfactant is not less than 3 hours (stirring and mixing). At the same time, the system should be stable and free of foam formation.

[0066] The optimal temperature for step (2) is 30°C, and ultrasonic equipment can be used as an aid to accelerate dissolution.

[0067] The stirring rate involved in step (3) needs to be selected according to the scale of the reaction.

[0068] The reaction time in step (4) can be selected according to the requirements; the yield of the sample varies under different reaction times, and the optimal reaction time is 2h.

[0069] The drying process in step (5) can be room temperature drying, oven drying, or freeze drying.

[0070] The aromatic amine-acid is one of 3,5-diaminobenzoic acid, 2,3-diaminobenzoic acid, 3,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, 2,4-diaminobenzenesulfonic acid, 2,5-diaminobenzenesulfonic acid, 2-aminobenzenesulfonic acid, 3-aminobenzenesulfonic acid, and 4-aminobenzenesulfonic acid.

[0071] In step (6), the carbonization temperature can be used to control the specific surface area, porosity, conductivity and nitrogen content of the target product. The carbonization temperature range is 300℃~1000℃, and the heating rate of the carbonization process is 1℃ / min or 2℃ / min.

[0072] The method described above in this invention uses melamine, aromatic amine-acid, and aliphatic aldehyde as basic raw materials. The aromatic amine-acid preferentially reacts with the introduced aliphatic aldehyde to form a Schiff base intermediate. Subsequently, melamine and the Schiff base intermediate undergo an addition reaction and crosslink to form melamine-based oligomers. Anionic and nonionic surfactants are used as co-templating agents, and the synergistic effect between the composite surfactants is utilized to construct nanomicelles. The melamine-based oligomers and nanomicelles interact based on Coulomb forces and hydrogen bonds, and synergistically co-assemble (self-assemble) into composite polymer nanospheres. After solid-liquid separation, washing, and drying, nitrogen-doped mesoporous polymer nanospheres are obtained. The obtained nitrogen-doped mesoporous polymer nanospheres are then carbonized under an inert atmosphere to obtain nitrogen-doped mesoporous carbon nanospheres with essentially unchanged morphology and structure. The prepared materials have consistent and stable morphology and structure, good monodispersity, uniform and high nitrogen atom distribution with adjustable content, and good reproducibility.

[0073] The nitrogen-doped mesoporous polymer nanospheres prepared by this invention have an adjustable particle size between 65 nm and 1 μm. The nitrogen content is adjustable between 5% and 50%. The nitrogen-doped mesoporous carbon nanospheres have a particle size between 50 nm and 1 μm and a specific surface area of ​​300–600 m². 2 / g, total pore volume is 0.6–2.5 cm³ 3 / g. Mesopore volume is 0.40–2.0 cm³. 3 / g, with mesoporous pore sizes ranging from 5 to 40 nm. Compared to the hard template method commonly used for preparing mesoporous materials, the soft template method designed in this invention, namely the dual-template synergistic assembly method, is simpler, more efficient, stable, and reliable, and can still maintain good morphology and structure after large-scale scale-up.

[0074] Example 1

[0075] 0.020 g (0.066 mmol) of sodium oleate (SO₄) and 0.060 g (0.010 mmol) of P123 were dissolved in 20 mL of deionized water and stirred vigorously for at least 3 h (or sonicated for 30 min). The resulting mixture is denoted as solution A. 0.504 g (4.000 mmol) of melamine and 0.091 g (0.600 mmol) of 3,5-diaminobenzoic acid were dissolved in 180 mL of deionized water at 30 °C. This mixture is denoted as solution B. Solution A was then completely transferred to solution B and stabilized at 30 °C and 500 rpm for 60 min. Under the same conditions, 4 mL of formaldehyde solution was added to initiate the polymerization reaction, and the reaction was continued for 2 h to obtain a purplish-gray turbid liquid. The obtained liquid was centrifuged at 10,000 rpm for 20 min and washed three times with water to obtain a purplish-gray solid. The obtained solid was dried in an oven at 65°C for 12 h to obtain nitrogen-doped mesoporous polymer nanospheres, and their morphology was characterized by scanning electron microscopy (SEM). Figure 1 The images show SEM images of the nitrogen-doped mesoporous polymer nanospheres. a and b are SEM images at different magnifications, and c is the particle size distribution of the sample after 100 random statistical analyses. The results show that the sample exhibits a typical spherical morphology with a rough surface and a particle size of less than 100 nm, with the average particle size mainly distributed around 65 nm.

[0076] Example 2

[0077] 0.020 g (0.066 mmol) of sodium oleate (SO₄) and 0.060 g (0.010 mmol) of P123 were dissolved in 20 mL of deionized water and stirred vigorously for at least 3 h (or sonicated for 30 min). The resulting mixture is denoted as solution A. 0.504 g (4.000 mmol) of melamine and 0.091 g (0.600 mmol) of 3,5-diaminobenzoic acid were dissolved in 180 mL of deionized water at 30 °C. This mixture is denoted as solution B. Solution A was then completely transferred to solution B and stabilized at 30 °C and 500 rpm for 60 min. Under the same conditions, 4 mL of formaldehyde solution was added to initiate the polymerization reaction, and the reaction was continued for 2 h to obtain a purplish-gray turbid liquid. The obtained liquid was centrifuged at 10,000 rpm for 20 min and washed three times with water to obtain a purplish-gray solid. The obtained solid was dried in an oven at 65°C for 12 h to obtain nitrogen-doped mesoporous polymer nanospheres, and their morphology and structure were characterized by transmission electron microscopy. Figure 2The images show TEM images of nitrogen-doped mesoporous polymer nanospheres, where a, b, and c are TEM images at different magnifications. The inset in a is the pore size distribution map, d is the STEM image, and e and f are the distribution images of elements C and N, respectively. The results show that the prepared samples exhibit rich mesoporous pore characteristics, with an average pore size of about 6-7 nm. Furthermore, the distribution densities of C and N elements in the mesoporous polymer nanospheres are basically the same, revealing the high nitrogen doping characteristics.

[0078] Example 3

[0079] 0.504 g (4.000 mmol) of melamine and 0.091 g (0.600 mmol) of 3,5-diaminobenzoic acid were dissolved in 180 mL of deionized water at 30 °C. Subsequently, 4 mL of formaldehyde solution was added to initiate the polymerization reaction, and the reaction was continued for 2 h with stirring at 500 rpm to obtain a purplish-gray turbid liquid. The obtained liquid was centrifuged at 10000 rpm for 20 min and washed three times with water to obtain a purplish-gray solid. The obtained solid was dried in an oven at 65 °C for 12 h to obtain nitrogen-doped polymer nanospheres, and their morphology and structure were characterized using transmission electron microscopy. Figure 3 The images are TEM images of nitrogen-doped polymer nanospheres. a and b are TEM images at different magnifications. The results show that no mesoporous structure exists in the prepared sample without the addition of surfactant, proving that surfactant is a template agent for the construction of mesoporous structure.

[0080] Example 4

[0081] 0.020 g (0.066 mmol) of sodium oleate was dissolved in 20 mL of deionized water, denoted as solution A. 0.504 g (4.000 mmol) of melamine and 0.091 g (0.600 mmol) of 3,5-diaminobenzoic acid were dissolved in 180 mL of deionized water at 30 °C, denoted as solution B. Solution A was then completely transferred to solution B and stabilized at 30 °C and 500 rpm for 60 min. Subsequently, while maintaining the above conditions, 4 mL of formaldehyde solution was added to initiate the polymerization reaction, and the reaction was continued for 2 h to obtain a purplish-gray turbid liquid. The obtained liquid was centrifuged at 10000 rpm for 20 min and washed three times with water to obtain a purplish-gray solid. The obtained solid was dried in an oven at 65 °C for 12 h to obtain nitrogen-doped mesoporous polymer nanospheres, and their morphology and structure were characterized using transmission electron microscopy. Figure 4 The images show TEM images of nitrogen-doped polymers. The samples are ellipsoidal, and some samples have hollow structures. The results indicate that there is an interaction between sodium oleate and the precursor oligomer, which can affect the morphology and structure of the samples.

[0082] Example 5

[0083] 0.040 g (0.007 mmol) of P123 was dissolved in 20 mL of deionized water, denoted as solution A. 0.504 g (4.000 mmol) of melamine and 0.091 g (0.600 mmol) of 3,5-diaminobenzoic acid were dissolved in 180 mL of deionized water at 30 °C, denoted as solution B. Solution A was then completely transferred to solution B and stabilized at 30 °C and 500 rpm for 60 min. Subsequently, while maintaining the above conditions, 4 mL of formaldehyde solution was added to initiate the polymerization reaction, and the reaction was continued for 2 h to obtain a purplish-gray turbid liquid. The obtained liquid was centrifuged at 10000 rpm for 20 min and washed three times with water to obtain a purplish-gray solid. The obtained solid was dried in an oven at 65 °C for 12 h to obtain nitrogen-doped mesoporous polymer nanospheres, and their morphology and structure were characterized using transmission electron microscopy. Figure 5 The images show TEM images of nitrogen-doped polymer nanomaterials. Images a and b are TEM images at different magnifications. The results indicate that P123 interacts with the precursor oligomer and affects the mesoporous structure of the sample; combined with Examples 2-5 ( Figure 2-5 It can be seen that the combined use of anionic surfactant sodium oleate and nonionic surfactant P123 serves as a template for constructing mesoporous structures.

[0084] Example 6

[0085] The amount of sodium oleate (SO) used was fixed at 0.020 g (0.066 mmol). The mass ratio of sodium oleate to P123 was adjusted to 2 / 1, 1 / 1, 1 / 3, 1 / 4, and 1 / 5, respectively. Both were dissolved in 20 mL of deionized water and stirred vigorously for at least 3 h (or sonicated for 30 min). The resulting mixed liquid was denoted as solution A. 0.504 g (4.000 mmol) of melamine and 0.091 g (0.600 mmol) of 3,5-diaminobenzoic acid were dissolved in 180 mL of deionized water at 30 °C. This was denoted as solution B. Subsequently, solution A was completely transferred to solution B and stabilized at 30 °C and a stirring rate of 500 rpm for 60 min. Then, keeping the above conditions unchanged, 4 mL of formaldehyde solution was added to initiate the polymerization reaction, and the reaction was continued for 2 h to obtain a purplish-gray turbid liquid. The obtained liquid was centrifuged at 10,000 rpm for 20 min and washed three times with water to obtain a purplish-gray solid. The obtained solid was dried in an oven at 65 °C for 12 h to obtain a series of nitrogen-doped mesoporous polymer nanospheres, and their morphology and structure were characterized by transmission electron microscopy. Figure 6TEM images of nitrogen-doped mesoporous polymer nanospheres prepared under different SO / P123 mass ratios are shown. In the images, a represents SO / P123 ratio of 2 / 1, b represents SO / P123 ratio of 1 / 1, c represents SO / P123 ratio of 1 / 2, d represents SO / P123 ratio of 1 / 3, e represents SO / P123 ratio of 1 / 4, and f represents SO / P123 ratio of 1 / 5. The results indicate that the SO / P123 ratio affects the mesoporous structure of the samples, and the SO / P123 ratio should not be less than 3.

[0086] Example 7

[0087] Keeping the molar amounts of anionic and nonionic surfactants constant at 0.066 mmol and 0.010 mmol respectively, the types of composite surfactants were adjusted to sodium oleate-F127, sodium laurate (SL)-P123, sodium stearate (SS)-P123, sodium dodecyl sulfonate (SLS)-P123, and sodium dodecylbenzene sulfonate (SDBS)-F127, respectively, and dissolved in 20 mL of deionized water. The mixture was stirred vigorously for at least 3 h (or sonicated for 30 min), and the resulting mixed liquid was denoted as solution A. 0.504 g (4.000 mmol) of melamine and 0.091 g (0.600 mmol) of 3,5-diaminobenzoic acid were dissolved in 180 mL of deionized water at 30 °C, and this solution was denoted as solution B. Subsequently, solution A was completely transferred to solution B and stabilized at 30°C and 500 rpm for 60 min. Then, maintaining the above conditions, 4 mL of formaldehyde solution was added to initiate the polymerization reaction, and the reaction was continued for 2 h to obtain a purplish-gray turbid liquid. The obtained liquid was centrifuged at 10000 rpm for 20 min and washed three times with water to obtain a purplish-gray solid. The obtained solid was dried in an oven at 65°C for 12 h to obtain nitrogen-doped mesoporous polymer nanospheres, and their morphology and structure were characterized using transmission electron microscopy. Figure 7 The images show TEM images of nitrogen-doped mesoporous polymer nanospheres, where a is SO-F127, b is SL-P123, c and d are SS-P123, e is SLS-P123, and f is SDBS-P123. The results show that nonionic surfactants affect both the mesoporous structure and morphology of the target product; fatty acid salt surfactants are more favorable for the designed mesoporous structure.

[0088] Example 8

[0089] 0.020 g (0.066 mmol) of sodium oleate (SO4) and 0.060 g (0.010 mmol) of P123 were dissolved in 20 mL of deionized water and stirred vigorously for at least 3 h (or sonicated for 30 min). The resulting mixture was denoted as solution A. 0.504 g (4.000 mmol) of melamine was dissolved in 180 mL of deionized water with 0.6 mmol, 1.0 mmol, 1.4 mmol, 1.8 mmol, 2.2 mmol, and 2.6 mmol of 3,5-diaminobenzoic acid, respectively, at 30 °C. This mixture was denoted as solution B. Solution A was then completely transferred to solution B and stabilized at 30 °C and 500 rpm for 60 min. Under the same conditions, 4 mL of formaldehyde solution was added to initiate the polymerization reaction, and the reaction was continued for 2 h to obtain a purplish-gray turbid liquid. The obtained liquid was centrifuged at 10,000 rpm for 20 min and washed three times with water to obtain a purplish-gray solid. The obtained solid was dried in an oven at 65 °C for 12 h to obtain nitrogen-doped mesoporous polymer nanospheres, and their morphology and structure were characterized by transmission electron microscopy. Figure 8 TEM images of nitrogen-doped mesoporous polymer nanospheres prepared under different amounts of 3,5-diaminobenzoic acid. Images a, b, c, e, f, and g show TEM images of nitrogen-doped mesoporous polymer nanospheres prepared with 0.6 mmol, 1.0 mmol, 1.4 mmol, 1.8 mmol, 2.2 mmol, and 2.6 mmol of 3,5-diaminobenzoic acid, respectively. With increasing amounts of 3,5-diaminobenzoic acid, the prepared mesoporous polymers gradually changed from spherical to irregular shapes, and the particle size of the samples gradually increased, but the mesoporous structure of the samples did not change significantly.

[0090] Example 9

[0091] 1.000 g (3.300 mmol) of sodium oleate (SO4) and 3.000 g (0.500 mmol) of P123 were dissolved in 1000 mL of deionized water and stirred vigorously for at least 3 h (or sonicated for 30 min). The resulting mixture is denoted as solution A. 25.200 g (200.000 mmol) of melamine and 4.550 g (30.000 mmol) of 3,5-diaminobenzoic acid were dissolved in 9000 mL of deionized water at 30 °C. This mixture is denoted as solution B. Solution A was then completely transferred to solution B and stabilized at 30 °C and 500 rpm for 60 min. Under the same conditions, 200 mL of formaldehyde solution was added to initiate the polymerization reaction, and the reaction was continued for 2 h to obtain a purplish-gray turbid liquid. The obtained liquid was centrifuged at 10000 rpm for 20 min and washed three times with water to obtain a purplish-gray solid. The obtained solid was dried in an oven at 65°C for 12 h to obtain nitrogen-doped mesoporous polymer nanospheres, and their morphology and structure were characterized by transmission electron microscopy. Figure 9 The image shows a TEM image of the prepared sample magnified 50 times. The image shows that the sample retains a rich mesoporous structure after magnification 50 times, indicating that the method of the invention has the potential for large-scale production and utilization.

[0092] Example 10

[0093] 0.020 g (0.066 mmol) of sodium oleate (SO₄) and 0.060 g (0.010 mmol) of P123 were dissolved in 20 mL of deionized water and stirred vigorously for at least 3 h (or sonicated for 30 min). The resulting mixture was denoted as solution A. 0.504 g (4.000 mmol) of melamine and 0.091 g (0.600 mmol) of 2,3-diaminobenzoic acid were dissolved in 180 mL of deionized water at 30 °C. This mixture was denoted as solution B. Solution A was then completely transferred to solution B and stabilized at 30 °C and 500 rpm for 60 min. Under the same conditions, 4 mL of formaldehyde solution was added to initiate the polymerization reaction, and the reaction was continued for 2 h to obtain a purplish-gray turbid liquid. The obtained liquid was centrifuged at 10000 rpm for 20 min and washed three times with water to obtain a purplish-gray solid. The obtained solid was dried in an oven at 65°C for 12 h to obtain nitrogen-doped mesoporous polymer nanospheres, and their morphology and structure were characterized by transmission electron microscopy.

[0094] Example 11

[0095] 0.020 g (0.066 mmol) of sodium oleate (SO4) and 0.060 g (0.010 mmol) of P123 were dissolved in 20 mL of deionized water and stirred vigorously for at least 3 h (or sonicated for 30 min). The resulting mixture is denoted as solution A. 0.504 g (4.000 mmol) of melamine and 0.091 g (0.600 mmol) of 3,4-diaminobenzoic acid were dissolved in 180 mL of deionized water at 30 °C. This mixture is denoted as solution B. Solution A was then completely transferred to solution B and stabilized at 30 °C and 500 rpm for 60 min. Under the same conditions, 4 mL of formaldehyde solution was added to initiate the polymerization reaction, and the reaction was continued for 2 h to obtain a purplish-gray turbid liquid. The obtained liquid was centrifuged at 10,000 rpm for 20 min and washed three times with water to obtain a purplish-gray solid. The obtained solid was dried in an oven at 65°C for 12 h to obtain nitrogen-doped mesoporous polymer nanospheres, and their morphology and structure were characterized by transmission electron microscopy.

[0096] Example 12

[0097] 0.020 g (0.066 mmol) of sodium oleate (SO4) and 0.060 g (0.010 mmol) of P123 were dissolved in 20 mL of deionized water and stirred vigorously for at least 3 h (or sonicated for 30 min). The resulting mixture is denoted as solution A. 0.504 g (4.000 mmol) of melamine and 0.082 g (0.600 mmol) of 2-diaminobenzoic acid were dissolved in 180 mL of deionized water at 30 °C. This mixture is denoted as solution B. Solution A was then completely transferred to solution B and stabilized at 30 °C and 500 rpm for 60 min. Under the same conditions, 4 mL of formaldehyde solution was added to initiate the polymerization reaction, and the reaction was continued for 2 h to obtain a purplish-gray turbid liquid. The obtained liquid was centrifuged at 10000 rpm for 20 min and washed three times with water to obtain a purplish-gray solid. The obtained solid was dried in an oven at 65°C for 12 h to obtain nitrogen-doped mesoporous polymer nanospheres, and their morphology and structure were characterized by transmission electron microscopy.

[0098] Example 13

[0099] 0.020 g (0.066 mmol) of sodium oleate (SO₄) and 0.060 g (0.010 mmol) of P123 were dissolved in 20 mL of deionized water and stirred vigorously for at least 3 h (or sonicated for 30 min). The resulting mixture is denoted as solution A. 0.504 g (4.000 mmol) of melamine and 0.082 g (0.600 mmol) of 3-aminobenzoic acid were dissolved in 180 mL of deionized water at 30 °C. This mixture is denoted as solution B. Solution A was then completely transferred to solution B and stabilized at 30 °C and 500 rpm for 60 min. Under the same conditions, 4 mL of formaldehyde solution was added to initiate the polymerization reaction, and the reaction was continued for 2 h to obtain a purplish-gray turbid liquid. The obtained liquid was centrifuged at 10000 rpm for 20 min and washed three times with water to obtain a purplish-gray solid. The obtained solid was dried in an oven at 65°C for 12 h to obtain nitrogen-doped mesoporous polymer nanospheres, and their morphology and structure were characterized by transmission electron microscopy.

[0100] Example 14

[0101] 0.020 g (0.066 mmol) of sodium oleate (SO₄) and 0.060 g (0.010 mmol) of P123 were dissolved in 20 mL of deionized water and stirred vigorously for at least 3 h (or sonicated for 30 min). The resulting mixture is denoted as solution A. 0.504 g (4.000 mmol) of melamine and 0.082 g (0.600 mmol) of 4-aminobenzoic acid were dissolved in 180 mL of deionized water at 30 °C. This mixture is denoted as solution B. Solution A was then completely transferred to solution B and stabilized at 30 °C and 500 rpm for 60 min. Under the same conditions, 4 mL of formaldehyde solution was added to initiate the polymerization reaction, and the reaction was continued for 2 h to obtain a purplish-gray turbid liquid. The obtained liquid was centrifuged at 10000 rpm for 20 min and washed three times with water to obtain a purplish-gray solid. The obtained solid was dried in an oven at 65°C for 12 h to obtain nitrogen-doped mesoporous polymer nanospheres, and their morphology and structure were characterized by transmission electron microscopy.

[0102] Example 15

[0103] 0.020 g (0.066 mmol) of sodium oleate (SO4) and 0.060 g (0.010 mmol) of P123 were dissolved in 20 mL of deionized water and stirred vigorously for at least 3 h (or sonicated for 30 min). The resulting mixture is denoted as solution A. 0.504 g (4.000 mmol) of melamine and 0.113 g (0.600 mmol) of 2,4-diaminobenzoic acid were dissolved in 180 mL of deionized water at 30 °C. This mixture is denoted as solution B. Solution A was then completely transferred to solution B and stabilized at 30 °C and 500 rpm for 60 min. Under the same conditions, 4 mL of formaldehyde solution was added to initiate the polymerization reaction, and the reaction was continued for 2 h to obtain a purplish-gray turbid liquid. The obtained liquid was centrifuged at 10000 rpm for 20 min and washed three times with water to obtain a purplish-gray solid. The obtained solid was dried in an oven at 65°C for 12 h to obtain nitrogen-doped mesoporous polymer nanospheres, and their morphology and structure were characterized by transmission electron microscopy.

[0104] Example 16

[0105] 0.020 g (0.066 mmol) of sodium oleate (SO4) and 0.060 g (0.010 mmol) of P123 were dissolved in 20 mL of deionized water and stirred vigorously for at least 3 h (or sonicated for 30 min). The resulting mixture is denoted as solution A. 0.504 g (4.000 mmol) of melamine and 0.113 g (0.600 mmol) of 2,5-diaminobenzoic acid were dissolved in 180 mL of deionized water at 30 °C. This mixture is denoted as solution B. Solution A was then completely transferred to solution B and stabilized at 30 °C and 500 rpm for 60 min. Under the same conditions, 4 mL of formaldehyde solution was added to initiate the polymerization reaction, and the reaction was continued for 2 h to obtain a purplish-gray turbid liquid. The obtained liquid was centrifuged at 10000 rpm for 20 min and washed three times with water to obtain a purplish-gray solid. The obtained solid was dried in an oven at 65°C for 12 h to obtain nitrogen-doped mesoporous polymer nanospheres, and their morphology and structure were characterized by transmission electron microscopy.

[0106] Example 17

[0107] 0.020 g (0.066 mmol) of sodium oleate (SO4) and 0.060 g (0.010 mmol) of P123 were dissolved in 20 mL of deionized water and stirred vigorously for at least 3 h (or sonicated for 30 min). The resulting mixture is denoted as solution A. 0.504 g (4.000 mmol) of melamine and 0.104 g (0.600 mmol) of 2-aminobenzoic acid were dissolved in 180 mL of deionized water at 30 °C. This mixture is denoted as solution B. Solution A was then completely transferred to solution B and stabilized at 30 °C and 500 rpm for 60 min. Under the same conditions, 4 mL of formaldehyde solution was added to initiate the polymerization reaction, and the reaction was continued for 2 h to obtain a purplish-gray turbid liquid. The obtained liquid was centrifuged at 10000 rpm for 20 min and washed three times with water to obtain a purplish-gray solid. The obtained solid was dried in an oven at 65°C for 12 h to obtain nitrogen-doped mesoporous polymer nanospheres, and their morphology and structure were characterized by transmission electron microscopy.

[0108] Example 18

[0109] 0.020 g (0.066 mmol) of sodium oleate (SO₄) and 0.060 g (0.010 mmol) of P123 were dissolved in 20 mL of deionized water and stirred vigorously for at least 3 h (or sonicated for 30 min). The resulting mixture is denoted as solution A. 0.504 g (4.000 mmol) of melamine and 0.104 g (0.600 mmol) of 3-aminobenzoic acid were dissolved in 180 mL of deionized water at 30 °C. This mixture is denoted as solution B. Solution A was then completely transferred to solution B and stabilized at 30 °C and 500 rpm for 60 min. Under the same conditions, 4 mL of formaldehyde solution was added to initiate the polymerization reaction, and the reaction was continued for 2 h to obtain a purplish-gray turbid liquid. The obtained liquid was centrifuged at 10000 rpm for 20 min and washed three times with water to obtain a purplish-gray solid. The obtained solid was dried in an oven at 65°C for 12 h to obtain nitrogen-doped mesoporous polymer nanospheres, and their morphology and structure were characterized by transmission electron microscopy.

[0110] Example 19

[0111] 0.020 g (0.066 mmol) of sodium oleate (SO4) and 0.060 g (0.010 mmol) of P123 were dissolved in 20 mL of deionized water and stirred vigorously for at least 3 h (or sonicated for 30 min). The resulting mixture is denoted as solution A. 0.504 g (4.000 mmol) of melamine and 0.104 g (0.600 mmol) of 4-aminobenzoic acid were dissolved in 180 mL of deionized water at 30 °C. This mixture is denoted as solution B. Solution A was then completely transferred to solution B and stabilized at 30 °C and 500 rpm for 60 min. Under the same conditions, 4 mL of formaldehyde solution was added to initiate the polymerization reaction, and the reaction was continued for 2 h to obtain a purplish-gray turbid liquid. The obtained liquid was centrifuged at 10000 rpm for 20 min and washed three times with water to obtain a purplish-gray solid. The obtained solid was dried in an oven at 65°C for 12 h to obtain nitrogen-doped mesoporous polymer nanospheres, and their morphology and structure were characterized by transmission electron microscopy.

[0112] Example 20

[0113] 0.020 g (0.066 mmol) of sodium oleate (SO4) and 0.060 g (0.010 mmol) of P123 were dissolved in 20 mL of deionized water and stirred vigorously for at least 3 h (or sonicated for 30 min). The resulting mixture is denoted as solution A. 0.504 g (4.000 mmol) of melamine and 0.091 g (0.600 mmol) of 3,5-diaminobenzoic acid were dissolved in 180 mL of deionized water at 30 °C. This mixture is denoted as solution B. Solution A was then completely transferred to solution B and stabilized at 30 °C and 500 rpm for 60 min. Under the same conditions, 4 mL of acetaldehyde solution was added to initiate the polymerization reaction, and the reaction was continued for 2 h to obtain a purplish-gray turbid liquid. The obtained liquid was centrifuged at 10,000 rpm for 20 min and washed three times with water to obtain a purplish-gray solid. The obtained solid was dried in an oven at 65°C for 12 h to obtain nitrogen-doped mesoporous polymer nanospheres, and their morphology and structure were characterized by transmission electron microscopy.

[0114] Example 21

[0115] 0.020 g (0.066 mmol) of sodium oleate (SO₄) and 0.060 g (0.010 mmol) of P123 were dissolved in 20 mL of deionized water and stirred vigorously for at least 3 h (or sonicated for 30 min). The resulting mixture was denoted as solution A. 0.504 g (4.000 mmol) of melamine and 0.091 g (0.600 mmol) of 3,5-diaminobenzoic acid were dissolved in 180 mL of deionized water at 30 °C. This mixture was denoted as solution B. Solution A was then completely transferred to solution B and stabilized at 30 °C and 500 rpm for 60 min. Under the same conditions, 4 mL of glyoxal solution was added to initiate the polymerization reaction, and the reaction was continued for 2 h to obtain a purplish-gray turbid liquid. The obtained liquid was centrifuged at 10,000 rpm for 20 min and washed three times with water to obtain a purplish-gray solid. The obtained solid was dried in an oven at 65°C for 12 h to obtain nitrogen-doped mesoporous polymer nanospheres, and their morphology and structure were characterized by transmission electron microscopy.

[0116] Example 22

[0117] 0.020 g (0.066 mmol) of sodium oleate (SO4) and 0.060 g (0.010 mmol) of P123 were dissolved in 20 mL of deionized water and stirred vigorously for at least 3 h (or sonicated for 30 min). The resulting mixture was denoted as solution A. 0.504 g (4.000 mmol) of melamine and 0.091 g (0.600 mmol) of 3,5-diaminobenzoic acid were dissolved in 180 mL of deionized water at 30 °C. This mixture was denoted as solution B. Solution A was then completely transferred to solution B and stabilized at 30 °C and 500 rpm for 60 min. Under the same conditions, 4 mL of glutaraldehyde solution was added to initiate the polymerization reaction, and the reaction was continued for 2 h to obtain a purplish-gray turbid liquid. The obtained liquid was centrifuged at 10000 rpm for 20 min and washed three times with water to obtain a purplish-gray solid. The obtained solid was dried in an oven at 65°C for 12 h to obtain nitrogen-doped mesoporous polymer nanospheres, and their morphology and structure were characterized by transmission electron microscopy.

[0118] Example 23

[0119] 0.020 g (0.066 mmol) of sodium oleate (SO₄) and 0.060 g (0.010 mmol) of P123 were dissolved in 20 mL of deionized water and stirred vigorously for at least 3 h (or sonicated for 30 min). The resulting mixture was denoted as solution A. 0.504 g (4.000 mmol) of melamine and 0.091 g (0.600 mmol) of 3,5-diaminobenzoic acid were dissolved in 180 mL of deionized water at 30 °C. This mixture was denoted as solution B. Solution A was then completely transferred to solution B and stabilized at 30 °C and 500 rpm for 60 min. Under the same conditions, 4 mL of hexamethylenetetramine solution was added to initiate the polymerization reaction, and the reaction was continued for 2 h to obtain a purplish-gray turbid liquid. The obtained liquid was centrifuged at 10,000 rpm for 20 min and washed three times with water to obtain a purplish-gray solid. The obtained solid was dried in an oven at 65°C for 12 h to obtain nitrogen-doped mesoporous polymer nanospheres, and their morphology and structure were characterized by transmission electron microscopy.

[0120] Example 24

[0121] 0.020 g (0.066 mmol) of sodium oleate (SO₄) and 0.060 g (0.010 mmol) of P123 were dissolved in 20 mL of deionized water and stirred vigorously for at least 3 h (or sonicated for 30 min). The resulting mixture is denoted as solution A. 0.504 g (4.000 mmol) of melamine and 0.091 g (0.600 mmol) of 3,5-diaminobenzoic acid were dissolved in 180 mL of deionized water at 30 °C. This mixture is denoted as solution B. Solution A was then completely transferred to solution B and stabilized at 30 °C and 500 rpm for 60 min. Under the same conditions, 4 mL of formaldehyde solution was added to initiate the polymerization reaction, and the reaction was continued for 2 h to obtain a purplish-gray turbid liquid. The obtained liquid was centrifuged at 10,000 rpm for 20 min and washed three times with water to obtain a purplish-gray solid. The obtained solid was dried in an oven at 65°C for 12 h to obtain nitrogen-doped mesoporous polymer nanospheres. The weight loss curves of the above samples were tested under a nitrogen atmosphere at a heating rate of 10°C / min within a temperature range of room temperature to 800°C. Figure 24 The image shows the weight loss curve (TGA) of nitrogen-doped mesoporous polymer nanospheres. Figure 24The blue curve (NMePS) represents the weight loss curve of the prepared nitrogen-doped mesoporous polymer nanospheres, while the red curve represents the weight loss curve of the nitrogen-doped polymer nanospheres prepared without the use of surfactant (without SO-P123). The results show that the weight loss rate of the mesoporous polymer nanospheres is faster than that of the non-porous polymer, which is attributed to the improved mass and heat transfer capabilities of the sample due to the mesoporous structure.

[0122] Example 25

[0123] 0.020 g (0.066 mmol) of sodium oleate (SO₄) and 0.060 g (0.010 mmol) of P123 were dissolved in 20 mL of deionized water and stirred vigorously for at least 3 h (or sonicated for 30 min). The resulting mixture is denoted as solution A. 0.504 g (4.000 mmol) of melamine and 0.091 g (0.600 mmol) of 3,5-diaminobenzoic acid were dissolved in 180 mL of deionized water at 30 °C. This mixture is denoted as solution B. Solution A was then completely transferred to solution B and stabilized at 30 °C and 500 rpm for 60 min. Under the same conditions, 4 mL of formaldehyde solution was added to initiate the polymerization reaction, and the reaction was continued for 2 h to obtain a purplish-gray turbid liquid. The obtained liquid was centrifuged at 10,000 rpm for 20 min and washed three times with water to obtain a purplish-gray solid. The obtained solid was dried in an oven at 65°C for 12 h to obtain nitrogen-doped mesoporous polymer nanospheres. Subsequently, the obtained solid polymer was ground into a solid powder using a mortar and pestle and uniformly spread in a long crucible. The crucible filled with the sample was transferred to a tube furnace, and the temperature of the tube furnace was raised to 100°C at a heating rate of 10°C / min under a nitrogen atmosphere. Then, the temperature was raised to 350°C at a heating rate of 1°C / min and pyrolyzed at this temperature for 2 h to remove unstable substances and residual template. Next, the temperature was raised to 700°C after a heating time of 2 h and further carbonized at this temperature for 2 h. After natural cooling to room temperature, the black carbon powder, i.e., nitrogen-doped mesoporous carbon nanospheres, was collected and its morphology was characterized using scanning electron microscopy. Figure 25 SEM images and particle size distribution of the prepared nitrogen-doped mesoporous carbon nanospheres are shown; a and b are SEM images at different magnifications, and c is the particle size distribution of the sample after 100 random statistical analyses. The results show that after carbonization and pyrolysis, the sample still maintains a good spherical morphology, and the particle size of the sample decreases due to the shrinkage of the polymer network skeleton during the pyrolysis process.

[0124] Example 26

[0125] 0.020 g (0.066 mmol) of sodium oleate (SO₄) and 0.060 g (0.010 mmol) of P123 were dissolved in 20 mL of deionized water and stirred vigorously for at least 3 h (or sonicated for 30 min). The resulting mixture is denoted as solution A. 0.504 g (4.000 mmol) of melamine and 0.091 g (0.600 mmol) of 3,5-diaminobenzoic acid were dissolved in 180 mL of deionized water at 30 °C. This mixture is denoted as solution B. Solution A was then completely transferred to solution B and stabilized at 30 °C and 500 rpm for 60 min. Under the same conditions, 4 mL of formaldehyde solution was added to initiate the polymerization reaction, and the reaction was continued for 2 h to obtain a purplish-gray turbid liquid. The obtained liquid was centrifuged at 10,000 rpm for 20 min and washed three times with water to obtain a purplish-gray solid. The obtained solid was dried in an oven at 65°C for 12 h to obtain nitrogen-doped mesoporous polymer nanospheres. Subsequently, the obtained solid polymer was ground into a powder using a mortar and pestle and uniformly spread in a long crucible. The crucible filled with the sample was transferred to a tube furnace, and the temperature of the tube furnace was increased to 100°C at a heating rate of 10°C / min under a nitrogen atmosphere. Then, the temperature was increased to 350°C at a heating rate of 1°C / min and pyrolyzed at this temperature for 2 h to remove unstable substances and residual template. Next, the temperature was increased to 700°C after a 2 h heating period and further carbonized at this temperature for 2 h. After natural cooling to room temperature, the black carbon powder, i.e., the nitrogen-doped mesoporous carbon nanospheres, was collected, and their structure was characterized using transmission electron microscopy. Figure 26 The images show TEM images and elemental distribution images of nitrogen-doped mesoporous carbon nanospheres. a, b, and c are TEM images of the sample at different magnifications, d is the STEM image of the sample, and e and f are the C and N elemental distribution images. The results show that the sample has abundant mesoporous structure and the N atom distribution density is similar to that of carbon atom, exhibiting excellent nitrogen atom doping characteristics.

[0126] Example 27

[0127] 0.020 g (0.066 mmol) of sodium oleate (SO₄) and 0.060 g (0.010 mmol) of P123 were dissolved in 20 mL of deionized water and stirred vigorously for at least 3 h (or sonicated for 30 min). The resulting mixture is denoted as solution A. 0.504 g (4.000 mmol) of melamine and 0.091 g (0.600 mmol) of 3,5-diaminobenzoic acid were dissolved in 180 mL of deionized water at 30 °C. This mixture is denoted as solution B. Solution A was then completely transferred to solution B and stabilized at 30 °C and 500 rpm for 60 min. Under the same conditions, 4 mL of formaldehyde solution was added to initiate the polymerization reaction, and the reaction was continued for 2 h to obtain a purplish-gray turbid liquid. The obtained liquid was centrifuged at 10,000 rpm for 20 min and washed three times with water to obtain a purplish-gray solid. The obtained solid was dried in an oven at 65°C for 12 hours to obtain nitrogen-doped mesoporous polymer nanospheres. Subsequently, the obtained solid polymer was ground into a powder using a mortar and pestle and uniformly spread in a long crucible. The crucible filled with the sample was transferred to a tube furnace, and the temperature of the tube furnace was increased to 100°C at a heating rate of 10°C / min under a nitrogen atmosphere. Then, the temperature was increased to 350°C at a heating rate of 1°C / min and pyrolyzed at this temperature for 2 hours to remove unstable substances and residual template. Next, the temperature was increased to 700°C after a 2-hour heating period and further carbonized at this temperature for 2 hours. After natural cooling to room temperature, the black carbon powder, i.e., the nitrogen-doped mesoporous carbon nanospheres, was collected and characterized using a physical adsorption analyzer to obtain nitrogen adsorption-desorption curves and pore size distribution. Figure 27 The physical structure of the samples is characterized as follows: a and b are the nitrogen adsorption-desorption isotherms and BJH pore size distribution of the nitrogen-doped mesoporous carbon nanospheres, respectively; c and d are the nitrogen adsorption-desorption isotherms and BJH pore size distribution of the nitrogen-doped carbon nanospheres. The results further indicate that the prepared samples exhibit typical mesoporous structure characteristics with pore sizes concentrated around 5.5 nm.

[0128] Example 28

[0129] 0.020 g (0.066 mmol) of sodium oleate (SO₄) and 0.060 g (0.010 mmol) of P123 were dissolved in 20 mL of deionized water and stirred vigorously for at least 3 h (or sonicated for 30 min). The resulting mixture is denoted as solution A. 0.504 g (4.000 mmol) of melamine and 0.091 g (0.600 mmol) of 3,5-diaminobenzoic acid were dissolved in 180 mL of deionized water at 30 °C. This mixture is denoted as solution B. Solution A was then completely transferred to solution B and stabilized at 30 °C and 500 rpm for 60 min. Under the same conditions, 4 mL of formaldehyde solution was added to initiate the polymerization reaction, and the reaction was continued for 2 h to obtain a purplish-gray turbid liquid. The obtained liquid was centrifuged at 10,000 rpm for 20 min and washed three times with water to obtain a purplish-gray solid. The obtained solid was dried in an oven at 65°C for 12 h to obtain nitrogen-doped mesoporous polymer nanospheres. Subsequently, the obtained solid polymer was ground into a powder using a mortar and pestle and uniformly spread in a long crucible. The crucible filled with the sample was transferred to a tube furnace, and the temperature of the tube furnace was raised to 100°C at a heating rate of 10°C / min under a nitrogen atmosphere. Then, the temperature was raised to 350°C at a heating rate of 1°C / min and pyrolyzed at this temperature for 2 h to remove unstable substances and residual template. Next, the temperature was raised to 700°C after a 2 h heating period and further carbonized at this temperature for 2 h. After natural cooling to room temperature, the black carbon powder, i.e., the nitrogen-doped mesoporous carbon nanospheres, was collected, and its composition was characterized using X-ray photoelectron spectroscopy (XPS). Figure 28 The images show the XPS spectra of nitrogen-doped mesoporous carbon nanospheres. a, b, and c are the full XPS spectrum, C 1s high-resolution spectrum, and N 1s high-resolution spectrum, respectively. The results indicate that the prepared samples have excellent nitrogen-doping characteristics and are rich in nitrogen species.

[0130] Example 29

[0131] 0.020 g (0.066 mmol) of sodium oleate (SO₄) and 0.060 g (0.010 mmol) of P123 were dissolved in 20 mL of deionized water and stirred vigorously for at least 3 h (or sonicated for 30 min). The resulting mixture is denoted as solution A. 0.504 g (4.000 mmol) of melamine and 0.091 g (0.600 mmol) of 3,5-diaminobenzoic acid were dissolved in 180 mL of deionized water at 30 °C. This mixture is denoted as solution B. Solution A was then completely transferred to solution B and stabilized at 30 °C and 500 rpm for 60 min. Under the same conditions, 4 mL of formaldehyde solution was added to initiate the polymerization reaction, and the reaction was continued for 2 h to obtain a purplish-gray turbid liquid. The obtained liquid was centrifuged at 10,000 rpm for 20 min and washed three times with water to obtain a purplish-gray solid. The obtained solid was dried in an oven at 65°C for 12 h to obtain nitrogen-doped mesoporous polymer nanospheres. Subsequently, the obtained solid polymer was ground into a powder using a mortar and pestle and uniformly spread in a long crucible. The crucible filled with the sample was transferred to a tube furnace, and the temperature of the tube furnace was raised to 100°C at a heating rate of 10°C / min under a nitrogen atmosphere. Then, the temperature was raised to 350°C at a heating rate of 1°C / min and pyrolyzed at this temperature for 2 h to remove unstable substances and residual template. Next, the temperature was raised to 700°C after a 2 h heating time and further carbonized at this temperature for 2 h. After natural cooling to room temperature, the black carbon powder, i.e., the nitrogen-doped mesoporous carbon nanospheres, was collected and characterized using X-ray diffraction (XRD) and Raman spectroscopy. Figure 29 The XRD and Raman spectra of the prepared nitrogen-doped mesoporous carbon nanospheres are shown. The results indicate that the prepared samples exhibit typical amorphous carbon characteristics.

[0132] Example 30

[0133] 0.020 g (0.066 mmol) of sodium oleate (SO₄) and 0.060 g (0.010 mmol) of P123 were dissolved in 20 mL of deionized water and stirred vigorously for at least 3 h (or sonicated for 30 min). The resulting mixture is denoted as solution A. 0.504 g (4.000 mmol) of melamine and 0.091 g (0.600 mmol) of 3,5-diaminobenzoic acid were dissolved in 180 mL of deionized water at 30 °C. This mixture is denoted as solution B. Solution A was then completely transferred to solution B and stabilized at 30 °C and 500 rpm for 60 min. Under the same conditions, 4 mL of formaldehyde solution was added to initiate the polymerization reaction, and the reaction was continued for 2 h to obtain a purplish-gray turbid liquid. The obtained liquid was centrifuged at 10,000 rpm for 20 min and washed three times with water to obtain a purplish-gray solid. The obtained solid was dried in an oven at 65°C for 12 hours to obtain nitrogen-doped mesoporous polymer nanospheres. Subsequently, the obtained solid polymer was ground into a powder using a mortar and pestle and uniformly spread in a long crucible. The crucible filled with the sample was transferred to a tube furnace, and the temperature of the tube furnace was raised to 100°C at a heating rate of 10°C / min under a nitrogen atmosphere. Then, the temperature was raised to 350°C at a heating rate of 1°C / min and pyrolyzed at this temperature for 2 hours to remove unstable substances and residual template. Next, the temperature was raised to 700°C after a 2-hour heating period and further carbonized at this temperature for 2 hours. After natural cooling to room temperature, the black carbon powder, i.e., the nitrogen-doped mesoporous carbon nanospheres, was collected, and their adsorption capacity for carbon dioxide was tested. Figure 30 The adsorption capacity of nitrogen-doped mesoporous carbon materials for carbon dioxide is shown in figures a and b, respectively, at 25 °C and 0 °C. The results show that the prepared material exhibits CO2 adsorption capacities of 2.14 mmol / g and 3.11 mmol / g at atmospheric pressure and 25 °C and 0 °C, respectively. Under the same test conditions, the adsorption capacities for N2 are 0.4 mmol / g and 0.56 mmol / g, respectively, with a greater adsorption capacity for CO2.

[0134] Example 31

[0135] 0.020 g (0.066 mmol) of sodium oleate (SO₄) and 0.060 g (0.010 mmol) of P123 were dissolved in 20 mL of deionized water and stirred vigorously for at least 3 h (or sonicated for 30 min). The resulting mixture is denoted as solution A. 0.504 g (4.000 mmol) of melamine and 0.091 g (0.600 mmol) of 3,5-diaminobenzoic acid were dissolved in 180 mL of deionized water at 30 °C. This mixture is denoted as solution B. Solution A was then completely transferred to solution B and stabilized at 30 °C and 500 rpm for 60 min. Under the same conditions, 4 mL of formaldehyde solution was added to initiate the polymerization reaction, and the reaction was continued for 2 h to obtain a purplish-gray turbid liquid. The obtained liquid was centrifuged at 10,000 rpm for 20 min and washed three times with water to obtain a purplish-gray solid. The obtained solid was dried in an oven at 65°C for 12 hours to obtain nitrogen-doped mesoporous polymer nanospheres. Subsequently, the obtained solid polymer was ground into a powder using a mortar and pestle and uniformly spread in a long crucible. The crucible filled with the sample was transferred to a tube furnace, and the temperature of the tube furnace was increased to 100°C at a heating rate of 10°C / min under a nitrogen atmosphere. Then, the temperature was increased to 350°C at a heating rate of 1°C / min and pyrolyzed at this temperature for 2 hours to remove unstable substances and residual template. Next, the temperature was increased to 700°C after a 2-hour heating period and further carbonized at this temperature for 2 hours. After natural cooling to room temperature, the black carbon powder, i.e., the nitrogen-doped mesoporous carbon nanospheres, was collected, and its electrochemical performance as an electrode material in a three-electrode system was tested. Figure 31 The electrochemical performance of nitrogen-doped mesoporous carbon nanospheres as electrode materials in a three-electrode system is shown. a, b, and c represent the CV curves, GCD curves, and specific capacitance at different current densities, respectively. The results show that the CV curves of NMeCS remain quasi-rectangular with a slight hump at different scan rates, even at a high scan rate of 200 mV / s, indicating excellent capacitance performance. Its main charge storage mechanism is electric double-layer capacitance (EDLC), with a small amount of pseudocapacitance, exhibiting excellent electrochemical reversibility. The GCD curves at different current densities all show nearly linear symmetrical triangles, further confirming its EDLC characteristics as an electrode material. At a current density of 0.2 A / g, the calculated specific capacitance as an electrode material is 249 F / g, and at a current density of 20 A / g, it still exhibits a specific capacitance of 144 F / g.

[0136] Example 32

[0137] 0.020 g (0.066 mmol) of sodium oleate (SO₄) and 0.060 g (0.010 mmol) of P123 were dissolved in 20 mL of deionized water and stirred vigorously for at least 3 h (or sonicated for 30 min). The resulting mixture is denoted as solution A. 0.504 g (4.000 mmol) of melamine and 0.091 g (0.600 mmol) of 3,5-diaminobenzoic acid were dissolved in 180 mL of deionized water at 30 °C. This mixture is denoted as solution B. Solution A was then completely transferred to solution B and stabilized at 30 °C and 500 rpm for 60 min. Under the same conditions, 4 mL of formaldehyde solution was added to initiate the polymerization reaction, and the reaction was continued for 2 h to obtain a purplish-gray turbid liquid. The obtained liquid was centrifuged at 10,000 rpm for 20 min and washed three times with water to obtain a purplish-gray solid. The obtained solid was dried in an oven at 65°C for 12 hours to obtain nitrogen-doped mesoporous polymer nanospheres. Subsequently, the obtained solid polymer was ground into a powder using a mortar and pestle and uniformly spread in a long crucible. The crucible filled with the sample was transferred to a tube furnace, and the temperature of the tube furnace was increased to 100°C at a heating rate of 10°C / min under a nitrogen atmosphere. Then, the temperature was increased to 350°C at a heating rate of 1°C / min and pyrolyzed at this temperature for 2 hours to remove unstable substances and residual template. Next, the temperature was increased to 700°C after a 2-hour heating period and further carbonized at this temperature for 2 hours. After natural cooling to room temperature, the black carbon powder, i.e., the nitrogen-doped mesoporous carbon nanospheres, was collected, and its electrochemical performance as a negative electrode material for lithium-ion batteries was tested. Figure 32 The electrochemical performance of nitrogen-doped mesoporous carbon nanospheres as a negative electrode material for lithium-ion batteries is shown in Figure a. a) is the galvanostatic charge-discharge curve, b) is the cycle performance curve, c) is the charge-discharge curve at different current densities, and d) is the rate performance curve. The results show that the initial charge-discharge capacity of this electrode is 471 mAh g⁻¹. -1 and 474mAh g -1 The coulomb efficiency is 100.8%. After 100 cycles, its capacity is 384 mAh g. -1 In addition, rate performance was tested at different current densities. The electrode performed at 100, 200, 400, 600, 800, and 1000 mAh g⁻¹. -1 At current density, its discharge capacity is 534 mAh g. -1 433mAh g -1 355mAh g -1 299mAh g -1 270mAh g -1 And 248mAh g -1 It exhibits excellent lithium storage performance.

[0138] For anyone skilled in the art, many possible variations and modifications can be made to the technical solutions of this invention, or equivalent embodiments can be modified based on the disclosed technical content, without departing from the scope of the technical solutions of this invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this invention without departing from the content of the technical solutions of this invention should still fall within the protection scope of the technical solutions of this invention.

Claims

1. A method for preparing nitrogen-doped mesoporous nanospheres, characterized in that: Using anionic and nonionic surfactants as co-templating agents, nanomicelles were constructed through the synergistic effect between the two surfactants. Melamine and aromatic amine-acids were used as the main raw materials. After the introduction of aliphatic aldehydes, they formed Schiff base intermediates with aromatic amine-acids. Melamine then added to the Schiff base intermediates to crosslink them into melamine-based oligomers. The nanomicelles and oligomers were synergistically co-assembled to form composite polymer nanospheres. After separation, washing, drying, and calcination under an inert atmosphere, nitrogen-doped mesoporous nanospheres were obtained. The preparation method specifically includes the following steps: S1. Under conditions of 0~30℃, dissolve one of the anionic surfactant and the nonionic surfactant in water and stir vigorously for at least 3 hours or with ultrasonic assistance for at least 30 minutes to form a composite surfactant solution; the mass ratio of the nonionic surfactant to the anionic surfactant is not less than 3. S2. The composite surfactant solution obtained in S1 is added to the precursor solution to obtain a mixed solution. The mixed solution is stirred for at least 1 h to form a stable micelle system. The concentration of melamine in the mixed solution is 0.1 mM to 30 mM, the molar ratio of aromatic amine-acid to melamine is 1:(5-8), and the concentration of anionic surfactant in the mixed solution is 0.1 mM to 3.0 mM. S3. Add fatty aldehyde to the system of S2 and obtain an emulsion suspension under stirring; wherein the amount of fatty aldehyde is 1 equivalent or more of melamine; S4. The emulsion suspension is separated, washed, and dried, and then calcined under an inert atmosphere to obtain nitrogen-doped mesoporous nanospheres.

2. The method for preparing nitrogen-doped mesoporous nanospheres according to claim 1, characterized in that: The anionic surfactant is one of sodium oleate, sodium stearate, sodium laurate, sodium dodecyl sulfonate, and sodium dodecylbenzene sulfonate; the nonionic surfactant is one of F127 and P123.

3. The method for preparing nitrogen-doped mesoporous nanospheres according to claim 1, characterized in that, Fatty aldehydes are one of formaldehyde, acetaldehyde, glyoxal, glutaraldehyde, and adipaldehyde.

4. The method for preparing nitrogen-doped mesoporous nanospheres according to claim 1, characterized in that, The aromatic amine-acid is one of 3,5-diaminobenzoic acid, 2,3-diaminobenzoic acid, 3,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, 2,4-diaminobenzenesulfonic acid, 2,5-diaminobenzenesulfonic acid, 2-aminobenzenesulfonic acid, 3-aminobenzenesulfonic acid, and 4-aminobenzenesulfonic acid.

5. The method for preparing nitrogen-doped mesoporous carbon nanospheres according to claim 1, characterized in that: The calcination temperature is 300℃~1000℃; the heating rate of the heating program is 1℃ / min or 2℃ / min, and the calcination time is 30~180 min.

6. A nitrogen-doped mesoporous nanosphere, characterized in that: It is prepared by any of the preparation methods described in claims 1-5.

7. A nitrogen-doped mesoporous nanosphere according to claim 6, characterized in that: The nitrogen-doped mesoporous nanospheres have a particle size of 50 nm to 1 mm and a specific surface area of ​​300 to 600 m². 2 / g, total pore volume is 0.6~2.5 cm³ 3 / g; mesopore volume is 0.40~2.0 cm³. 3 / g, with mesopore diameters of 5~40 nm.

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