WO2022174427A1

WO2022174427A1 - Uniform nitrogen-doped graphene with interspersed distribution of 15n and 14n, preparation method, and application

Info

Publication number: WO2022174427A1
Application number: PCT/CN2021/077106
Authority: WO
Inventors: 黄木华; 罗贤升; 邓汉林; 彭山青; 张志豪; 刘向向; 郗淑萌
Original assignee: 北京理工大学
Priority date: 2021-02-18
Filing date: 2021-02-20
Publication date: 2022-08-25
Also published as: CN113045721B; CN113045721A

Abstract

The present invention provides a uniform nitrogen-doped graphene with interspersed distribution of ¹⁵N and ¹⁴N, a preparation method, and an application. In the preparation method, cheap and easily available ¹⁵N-labeled sodium nitrite or potassium nitrite is used as raw materials to form a reaction by means of a highly efficient diazonium salt to carry out triple coupling with 1,3,5-triaminobenzene, so that ¹⁵N selectively labels hexaaminobenzene hydrochloride at 2-, 4-, and 6-positions; and then on the basis of an efficient and mild polycondensation reaction between -C=O and -NH₂, efficient synthesis of uniform nitrogen-doped graphene with interspersed distribution of ¹⁵N and ¹⁴N is achieved. In this way, the method has the advantages such as simple operation, high feasibility, and high economic efficiency. In addition, by means of the method, a uniform nitrogen-doped graphene material with interspersed distribution of ¹⁵N and ¹⁴N is synthesized for the first time, and the labeled nitrogen-doped graphene material provides a large number of detectable signals by virtue of the regular and uniform distribution of ¹⁵N atoms inside the structure, thus providing a good platform for subsequent studies of the chemical structure and intrinsic physical and chemical properties of porous graphene nitride materials.

Description

15N and Uniform nitrogen-doped graphene with 14N interspersed distribution and preparation method and application

This application claims the priority of the Chinese patent application filed on February 18, 2021, with the application number of 2021101878935 and the invention titled "Uniform nitrogen-doped graphene with interspersed distribution of 15N and 14N and its preparation method and application", The entire contents of which are incorporated herein by reference.

technical field

The invention relates to the field of chemical materials, and mainly relates to a uniform nitrogen-doped graphene with interspersed distribution of ¹⁵ N and ¹⁴ N, and a preparation method and application thereof.

Background technique

Stable isotope labeling technology plays an important role in the fields of chemistry, materials, life and environmental sciences. Based on the difference in properties between stable isotope-labeled and non-labeled substances, people can use different analytical instruments such as mass spectrometry and nuclear magnetic resonance to obtain information such as the quantity and position changes of substances or elements. Problems such as transition provide a convenient and powerful tool. At the same time, isotope labeling technology also provides new methods and ideas for the study of major scientific issues such as the design and development of new materials, biological metabolism laws, and soil changes. Since Harold Urey's discovery of deuterium, the stable isotope of hydrogen, in 1934, and his subsequent Nobel Prize, a large number of reagents, compounds and applications containing deuterium labels have emerged. Since the 1980s, the production of other stable isotopes such as ¹³ C, ¹⁵ N, ¹⁸ O, and ³⁴ S has also grown rapidly. At present, stable isotope-labeled reagents such as heavy water, ¹³ CO ₂ and ¹⁵ N-labeled amino acids, isotope-labeled nucleotides, proteins and polymer materials have been widely used in scientific research.

As the most representative two-dimensional material, graphene has attracted extensive attention in many scientific and technological fields due to its excellent electrical, thermal and physicochemical properties. Graphene has a highly regular structure, smooth surface, stable chemical properties, and low reactivity, but it lacks tunability. There is a strong π-π stacking effect and van der Waals force between layers, which is prone to agglomeration, poor solvent dispersion, and many short circuits. The plate limits its subsequent application and needs to be improved by functional modification, among which the introduction of heteroatoms is the most effective modification method. Nitrogen is the most preferred dopant element. The size of nitrogen atom is the closest to carbon atom and has five outermost electrons. It is easy to integrate into the conjugated skeleton of graphene in the form of sp ² hybridization, showing high compatibility and stability. Scientists have synthesized graphene nitride materials with specific ratios, such as C ₂ N, C ₃ N, and C ₄ N, through a bottom-up strategy.

However, as a new class of nitrogen-doped graphene materials, its structure consists of only two elements, C and N, and it does not melt or dissolve, which makes its synthesis mechanism, chemical structure characterization and performance research very challenging. If a stable isotope labeling method can be developed to prepare selectively labeled graphene nitride materials, it will be of great theoretical significance. However, so far, there is no isotope-labeled nitrogen-doped graphene material that can be used for the study of physicochemical properties.

Therefore, a new type of nitrogen-doped graphene material is needed in the art to solve the problems existing in the existing nitrogen-doped graphene materials such as difficulty in structural characterization and high difficulty in research on physical and chemical properties.

SUMMARY OF THE INVENTION

In order to solve the above problems, the present invention provides a uniform nitrogen-doped graphene with interspersed distribution of ¹⁵ N and ¹⁴ N, and a preparation method and application thereof. The details are as follows:

In a first aspect, the present invention provides a uniform nitrogen-doped graphene interspersed with ¹⁵ N and ¹⁴ N, wherein the uniform nitrogen-doped graphene interspersed with ¹⁵ N and ¹⁴ N is distributed with ¹⁵ N and ¹⁴ N interspersed. The hexaaminobenzene hydrochloride is reactant, prepared by polycondensation reaction;

The repeating structural unit in the uniform nitrogen-doped graphene structure interspersed with ¹⁵ N and ¹⁴ N is the structure shown in the following structural formula I, and the structure of the hexaaminobenzene hydrochloride interspersed with ¹⁵ N and ¹⁴ N It is the structure shown by the following structural formula II:

Among them, ¹⁵ N and ¹⁴ N are uniformly interspersed and distributed in structural formula I.

In a second aspect, the present invention provides a method for preparing uniform nitrogen-doped graphene with interspersed distribution of ¹⁵ N and ¹⁴ N, the method comprising:

Step 1, using ¹⁵ N-labeled sodium nitrite or potassium nitrite, substituted aniline shown in structural formula III and 1,3,5-triaminobenzene hydrochloride shown in structural formula IV as reaction raw materials, successively through coupling reaction , the reduction reaction prepares the ¹⁵ N-labeled hexaaminobenzenetrihydrochloride represented by the structural formula II;

In step 2, using the ¹⁵ N-labeled hexaaminobenzenetrihydrochloride and cyclohexanone as reaction raw materials, polycondensation reaction, purification, and activation treatment are carried out in sequence to obtain the ¹⁵ N and ¹⁴ N interspersed distributions shown in structural formula I. Homogeneous nitrogen-doped graphene.

In a third aspect, the present invention provides an application of uniform nitrogen-doped graphene interspersed with ¹⁵ N and ¹⁴ N, the application comprising: doping the uniform nitrogen-doped graphene interspersed with ¹⁵ N and ¹⁴ N described in the first aspect Heterographene is applied to the preparation of graphene materials or modified graphene materials; or

Applying the uniform nitrogen-doped graphene with ¹⁵ N and ¹⁴ N interspersed and distributed as described in the first aspect above to the characterization or detection of physical and chemical properties of graphene materials or modified graphene materials; or

Applying the uniform nitrogen-doped graphene with the interspersed distribution ^of15N ^and14N described in the first aspect above to the precise chemical structure characterization of the uniform nitrogen-doped graphene porous material; or

The uniform nitrogen-doped graphene with the interspersed distribution of ¹⁵ N and ¹⁴ N described in the first aspect above is applied to the study of intrinsic physical and chemical properties, wherein the study of the properties includes: any one of optics, acoustics, electrical conductivity, and thermal conductivity species; or

Applying the uniform nitrogen-doped graphene with interspersed distribution of ¹⁵ N and ¹⁴ N described in the first aspect above to gas adsorption separation and research on its mechanism; or

The uniform nitrogen-doped graphene with interspersed distribution of ¹⁵ N and ¹⁴ N described in the first aspect above is applied to the study of single-atom catalysis mechanism.

The invention provides a uniform nitrogen-doped graphene with interspersed distribution of ¹⁵ N and ¹⁴ N, and a preparation method and application thereof. The method includes: step 1, using sodium nitrite or potassium nitrite labeled with ¹⁵ N, substituted aniline represented by structural formula II and 1,3,5-triaminobenzene hydrochloride represented by structural formula I as reaction raw materials, and sequentially The 15N-labeled hexaaminobenzenetrihydrochloride represented by structural formula V is prepared by coupling reaction and reduction reaction; in step 2, the ^15N -labeled hexaaminobenzenetrihydrochloride and cyclohexanone are used as reaction raw materials , performing polycondensation reaction, purification, and activation treatment in sequence to obtain uniform nitrogen-doped graphene with interspersed distribution of ¹⁵ N and ¹⁴ N shown in structural formula I. From inexpensive and readily available ¹⁵ N-labeled sodium or potassium nitrite as starting materials, ¹⁵ N and ¹⁴ N were achieved by triple coupling with 1,3,5-triaminobenzene through a highly efficient diazonium salt formation reaction Interspersed distribution of 2,4,6-position of hexaaminobenzene hydrochloride; based on the efficient and mild polycondensation reaction of -C=O and _-NH2 , to achieve uniform nitrogen-doped graphene with ¹⁵ N and ¹⁴ interspersed distribution. Efficient synthesis. Therefore, this method has the advantages of simple operation, strong feasibility, cost-effectiveness, etc. At the same time, through this method, uniform nitrogen-doped graphene with interspersed distribution of ¹⁵ N and ¹⁴ N was synthesized for the first time, and the labeled nitrogen-doped graphene was synthesized for the first time. The material provides a large number of detectable signals by virtue of the periodic and uniform distribution of ¹⁵ N atoms inside the structure, which provides a good platform for the subsequent study of the chemical structure and intrinsic physical and chemical properties of porous graphene nitride materials. The preparation method provided by the present invention at least also includes the following advantages:

1, the raw materials used in the present invention, such as aromatic amines such as aniline, hexanaphthene and tin dichloride, are basic chemical products, are cheap and easy to obtain, and the cost is lower, and the ¹⁵ N substitution material adopts sodium nitrite. Or potassium nitrite, which is also the easiest to obtain of its kind. Therefore, the method provided by the present invention has the advantage of economical and easy availability of reaction raw materials.

2. In the preparation method of the present invention, the products obtained after each reaction is completed are easy to separate and purify, and the yield is high, and can be synthesized in large quantities; at the same time, aromatic amines such as aniline can be recovered and reused as by-products of subsequent reduction reactions. , in line with the principle of atomic economy. Therefore, the method provided by the present invention has the advantages of cost-effectiveness, high product availability, and the like.

3. According to the preparation method provided by the present invention, hexaaminobenzene hydrochloride with uniform and interspersed distribution of ¹⁵ N and ¹⁴ N and subsequent ¹⁵ N and ¹⁴ N are obtained by the fixed-point diazonium salt coupling reaction of 1,3,5-triaminobenzene The uniform nitrogen-doped graphene with N interspersed distribution has the advantages of simple operation in each step, high yield, fast reaction rate, easy separation and collection of intermediate and final products, etc., which is conducive to structural identification and development of new properties.

4. In the whole reaction process of the preparation method of the present invention, there is no high-pressure reaction, the synthesis conditions are simpler and more feasible, no strong corrosive acids such as nitric acid and sulfuric acid are needed, the raw materials, intermediate products and the residues after the reaction are harmless, and the whole synthesis High process safety and low additional emissions.

To sum up, the present invention can successfully prepare ¹⁵ N-labeled sodium nitrite or potassium nitrite and 1,3,5- ^{triaminobenzene} as starting materials through coupling reaction and reduction reaction. The hexaaminobenzene with N and ¹⁴ N interspersed distribution is then subjected to a dehydration polycondensation reaction with cyclohexanone to obtain uniform nitrogen-doped graphene with ¹⁵ N and ¹⁴ N interspersed distribution. The preparation method is simple and feasible, and the intermediate and final products have high efficiency and are easy to separate and purify, which provides a solid foundation for subsequent research on similar nitrogen-doped materials.

The above description is only an overview of the technical solutions of the present invention, in order to be able to understand the technical means of the present invention more clearly, it can be implemented according to the content of the description, and in order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand , the following specific embodiments of the present invention are given.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative efforts.

1 shows a method flow chart of a method for preparing a uniform nitrogen-doped graphene with ¹⁵ N and ¹⁴ N interspersed distribution in an embodiment of the present invention;

Fig. 2 shows the solution hydrogen NMR spectrum of ¹⁵ N-labeled 2,4,6-trisazophenyl-1,3,5-triaminobenzene of Example 1 of the present invention;

Fig. 3 shows the solution carbon nuclear magnetic resonance spectrum of ¹⁵ N-labeled 2,4,6-trisazophenyl-1,3,5-triaminobenzene of Example 1 of the present invention;

Fig. 4 shows the solution NMR spectrum of ¹⁵ N-labeled 2,4,6-trisazophenyl-1,3,5-triaminobenzene of Example 1 of the present invention;

Fig. 5 shows the solid carbon nuclear magnetic resonance spectrum of ¹⁵ N-labeled 2,4,6-trisazophenyl-1,3,5-triaminobenzene of Example 1 of the present invention;

Fig. 6 shows the solid nuclear magnetic resonance nitrogen spectrum of ¹⁵ N-labeled 2,4,6-trisazophenyl-1,3,5-triaminobenzene of Example 1 of the present invention;

Fig. 7 shows the high-resolution mass spectrum of ¹⁵ N-labeled 2,4,6-trisazophenyl-1,3,5-triaminobenzene of Example 1 of the present invention;

Fig. 8 shows the Fourier transform infrared spectrum of ¹⁵ N-labeled 2,4,6-trisazophenyl-1,3,5-triaminobenzene of Example 1 of the present invention;

Fig. 9 shows the solution hydrogen nuclear magnetic resonance spectrum of ¹⁵ N-labeled hexaaminobenzene hydrochloride of Example 1 of the present invention;

Fig. 10 shows the solid carbon nuclear magnetic resonance spectrum of ¹⁵ N-labeled hexaaminobenzene hydrochloride of Example 1 of the present invention;

Fig. 11 shows the solid nuclear magnetic resonance nitrogen spectrum of ¹⁵ N-labeled hexaaminobenzene hydrochloride of Example 1 of the present invention;

Figure 12 shows the high-resolution mass spectrogram of ¹⁵ N-labeled hexaaminobenzene hydrochloride of Example 1 of the present invention;

Figure 13 shows the Fourier transform infrared spectrogram of the ¹⁵ N-labeled hexaaminobenzene hydrochloride of Example 1 of the present invention;

Figure 14 shows the solid carbon nuclear magnetic resonance spectrum of the nitrogen-doped graphene material with uniformly interspersed and distributed ¹⁵ N and ¹⁴ N of Example 1 of the present invention;

15 shows the solid-state nuclear magnetic resonance nitrogen spectrum of the nitrogen-doped graphene material with ¹⁵ N and ¹⁴ N uniformly interspersed and distributed according to Example 1 of the present invention;

Fig. 16 shows the Fourier transform infrared spectrum of the nitrogen-doped graphene material with ¹⁵ N and ¹⁴ N uniformly interspersed and distributed according to Example 1 of the present invention;

Fig. 17 shows the Raman spectrum diagram of the nitrogen-doped graphene material with ¹⁵ N and ¹⁴ N uniformly interspersed and distributed according to Example 1 of the present invention;

Fig. 18 shows the powder X-ray diffraction pattern of the nitrogen-doped graphene material with ¹⁵ N and ¹⁴ N uniformly interspersed and distributed according to Example 1 of the present invention;

FIG. 19 shows the X-ray photoelectron spectrum of the nitrogen-doped graphene material with uniformly interspersed and distributed ¹⁵ N and ¹⁴ N of Example 1;

Fig. 20 shows the scanning electron microscope image of the nitrogen-doped graphene material with ¹⁵ N and ¹⁴ N uniformly interspersed and distributed according to Example 1 of the present invention;

Fig. 21 shows the transmission electron microscope image of the nitrogen-doped graphene material with ¹⁵ N and ¹⁴ N uniformly interspersed and distributed according to Example 1 of the present invention;

Fig. 22 shows the solid carbon nuclear magnetic resonance spectrum of the nitrogen-doped graphene material with ¹⁵ N and ¹⁴ N uniformly interspersed and distributed according to Example 2 of the present invention;

Fig. 23 shows the Fourier transform infrared spectrum of the nitrogen-doped graphene material with ¹⁵ N and ¹⁴ N uniformly interspersed and distributed according to Example 2 of the present invention;

Figure 24 shows the scanning electron microscope image of the nitrogen-doped graphene material with ¹⁵ N and ¹⁴ N uniformly interspersed and distributed according to Example 2 of the present invention;

Fig. 25 shows the solid carbon nuclear magnetic resonance spectrum of the nitrogen-doped graphene material with uniformly interspersed ¹⁵ N and ¹⁴ N of Example 3 of the present invention;

FIG. 26 shows the Fourier transform infrared spectrum of the nitrogen-doped graphene material with ¹⁵ N and ¹⁴ N uniformly interspersed and distributed according to Example 3 of the present invention;

27 shows a scanning electron microscope image of the nitrogen-doped graphene material with uniformly interspersed and distributed ¹⁵ N and ¹⁴ N of Example 3 of the present invention;

Figure 28 shows the solid carbon nuclear magnetic resonance spectrum of the nitrogen-doped graphene material with uniformly interspersed and distributed ¹⁵ N and ¹⁴ N of Example 4 of the present invention;

Figure 29 shows the Fourier transform infrared spectrogram of the nitrogen-doped graphene material with ¹⁵ N and ¹⁴ N uniformly interspersed and distributed according to Example 4 of the present invention;

30 shows a scanning electron microscope image of the nitrogen-doped graphene material with uniformly interspersed and distributed ¹⁵ N and ¹⁴ N of Example 4 of the present invention;

Figure 31 shows the solid carbon nuclear magnetic resonance spectrum of the nitrogen-doped graphene material with 15N and 14N uniformly interspersed and distributed according to Example 5 of the present invention;

Figure 32 shows the Fourier transform infrared spectrogram of the nitrogen-doped graphene material with ¹⁵ N and ¹⁴ N uniformly interspersed and distributed according to Example 5 of the present invention;

Fig. 33 shows the scanning electron microscope image of the nitrogen-doped graphene material with ¹⁵ N and ¹⁴ N uniformly interspersed and distributed according to Example 5 of the present invention;

Fig. 34 shows the transmission electron microscope image of the nitrogen-doped graphene material with ¹⁵ N and ¹⁴ N uniformly interspersed and distributed according to Example 5 of the present invention;

Fig. 35 shows the thermogravimetric analysis diagram of the nitrogen-doped graphene material with ¹⁵ N and ¹⁴ N uniformly interspersed and distributed according to Example 7 of the present invention;

Figure 36 shows the Fourier transform infrared spectrum comparison diagram of ¹⁵ N-labeled and unlabeled 2,4,6-trisazophenyl-1,3,5-triaminobenzene of Example 8 of the present invention;

Figure 37 shows a high-resolution mass spectrometry comparison chart of ¹⁵ N-labeled and unlabeled 2,4,6-trisazophenyl-1,3,5-triaminobenzene of Example 8 of the present invention;

Fig. 38 shows the comparison diagram of solid NMR nitrogen spectra of ¹⁵ N-labeled and unlabeled 2,4,6-trisazophenyl-1,3,5-triaminobenzene of Example 8 of the present invention;

Figure 39 shows the Fourier transform infrared spectrum comparison diagram of ¹⁵ N-labeled and non-labeled hexaaminobenzene of Example 8 of the present invention;

Figure 40 shows the high-resolution mass spectrometry comparison diagram of ¹⁵ N-labeled and unlabeled hexaaminobenzene of Example 8 of the present invention;

Figure 41 shows the solid-state nuclear magnetic resonance nitrogen spectrum comparison diagram of ¹⁵ N-labeled and unlabeled hexaaminobenzene of Example 8 of the present invention;

Fig. 42 shows the Fourier infrared spectrum comparison diagram of the nitrogen-doped graphene material with uniformly interspersed and distributed ¹⁵ N and ¹⁴ N of Example 8 of the present invention and the non-labeled material;

Figure 43 shows a comparison diagram of solid-state nuclear magnetic resonance nitrogen spectra of the nitrogen-doped graphene material with uniformly interspersed and distributed ¹⁵ N and ¹⁴ N of Example 8 of the present invention and a non-labeled material;

FIG. 44 shows a graph of the pore size distribution calculated by NLDFT of the nitrogen-doped graphene material with ¹⁵ N and ¹⁴ N uniformly interspersed and distributed according to Example 9 of the present invention.

specific embodiment

The following examples are provided for a better understanding of the present invention, and are not limited to the best embodiments, and do not limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by combining with the features of other prior art shall fall within the protection scope of the present invention.

If the specific experimental steps or conditions are not indicated in the examples, it can be carried out according to the operations or conditions of the conventional experimental steps described in the prior art in the field. The reagents and other instruments used without the manufacturer's indication are all conventional reagent products that can be purchased in the market.

In order to solve the problems in existing nitrogen-doped graphene materials such as difficulty in structural characterization and high difficulty in researching physical and chemical properties, the technical idea proposed by the inventor of the present invention is: interspersed with ¹⁵ N in the graphene structure to obtain a large number of ¹⁵ The N-labeled graphene nitride material, then based on the combination of stable isotope labeling with the porous properties possessed in the structure of the C ₂ N material, facilitates the synthesis mechanism, chemical structure characterization and performance studies. Based on this technical concept, the specific implementation content of the present invention is as follows:

In a first aspect, an embodiment of the present invention provides a uniform nitrogen-doped graphene interspersed with ¹⁵ N and ¹⁴ N, and the uniform nitrogen-doped graphene interspersed with ¹⁵ N and ¹⁴ N is interspersed with ¹⁵ N and ¹⁴ N. The distributed hexaaminobenzene hydrochloride is a reactant, prepared by a polycondensation reaction;

The repeating structural unit in the uniform nitrogen-doped graphene structure interspersed with ¹⁵ N and ¹⁴ N is the structure shown in the following structural formula I, and the structure of hexaaminobenzene hydrochloride interspersed with ¹⁵ N and ¹⁴ N is the following The structure shown in structural formula II:

Wherein, ¹⁵ N and ¹⁴ N are evenly interspersed and distributed in structural formula I; R in the structural formula III, structural formula V and structural formula VI are the same, and the R=H, CH ₃ , NO ₂ , OCH ₃ , COOH, SO ₃ H, Any one of COC ₆ H ₅ , C(CH ₃ ) ₃ ; in the structural formula III, X=any one of Cl, Br, BF ₄ , and PF ₆ .

It can be seen from the repeating structural unit that ¹⁵ N and ¹⁴ N are evenly interspersed and distributed in structural formula I, and the content of ¹⁵ N is relatively high, which is characterized by easy detection and tracking.

In the embodiment of the present invention, uniform nitrogen-doped graphene with interspersed distribution of ¹⁵ N and ¹⁴ N was synthesized for the first time, and the nitrogen-doped graphene material after ¹⁵ N labeling, by virtue of the periodic uniform distribution of ¹⁵ N atoms inside the structure, provided A large number of detectable signals provide a good platform for the subsequent study of the chemical structure and intrinsic physical and chemical properties of porous graphene nitride materials. At the same time, the uniform nitrogen-doped graphene with interspersed distribution of ¹⁵ N and ¹⁴ N provided in this embodiment, based on a large number of ¹⁵ N markings, can also be applied to the precise chemical structure characterization of uniform nitrogen-doped graphene porous materials, optical, acoustic , electrical conductivity, thermal conductivity and other intrinsic physical and chemical properties research, gas adsorption separation and its mechanism research, single-atom catalysis mechanism research and other fields.

In a second aspect, an embodiment of the present invention provides a method for preparing uniform nitrogen-doped graphene with interspersed distribution of ¹⁵ N and ¹⁴ N. As shown in FIG. 1 , the preparation method includes:

Step 1 (S101), using sodium nitrite or potassium nitrite labeled with ¹⁵ N, substituted aniline shown in structural formula III and 1,3,5-triaminobenzene hydrochloride shown in structural formula IV as reaction raw materials, successively passing through The coupling reaction and the reduction reaction are used to prepare the ¹⁵ N-labeled hexaaminobenzenetrihydrochloride represented by the structural formula II.

During specific implementation, the specific operations of step 1 include: step 1-1, adopting a one-pot method, firstly using ¹⁵ N-labeled sodium nitrite or potassium nitrite and substituted aniline shown in structure III as raw materials, through diazotization reaction The ¹⁵ N-labeled diazonium salt shown in structural formula V is prepared, and then the ¹⁵ N-labeled diazonium salt and the 1,3,5-triaminobenzene hydrochloride shown in structural formula IV are used as raw materials to prepare by coupling reaction. to obtain ¹⁵ N-labeled 2,4,6-trisazophenyl-1,3,5-triaminobenzene represented by structural formula VI; in step 1-2, use the ¹⁵ N-labeled 2,4,6- Trisazophenyl-1,3,5-triaminobenzene is used as a reactant, and the ¹⁵ N-labeled hexaaminobenzenetrihydrochloride represented by the structural formula II is prepared by reduction reaction.

In this implementation step, in step 1-1, when the diazotization reaction is performed, the molar ratio of ¹⁵ N-labeled sodium nitrite or potassium nitrite to the substituted aniline is 1-1.1:1; the diazotization reaction The temperature is -5～5℃, and the reaction time is 10～30min. In the step 1-1, when the coupling reaction is performed, the molar ratio of ¹⁵ N-labeled diazonium salt to 1,3,5-triaminobenzene hydrochloride is 3-4:1; The reaction conditions are alkaline conditions, and the alkaline reagents to be added to construct the alkaline conditions include any one of sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate; the reaction temperature of the coupling reaction is -5 to 25° C., The reaction time is 15-120 min; the second solvent used in the coupling reaction includes at least one of methanol, ethanol, acetone, ethyl acetate, chloroform, tetrahydrofuran, N,N'-dimethylacetamide and deionized water.

In this implementation step, in steps 1-2, using ¹⁵ N-labeled 2,4,6-trisazophenyl-1,3,5-triaminobenzene as a reactant, the compound of structural formula II is obtained by reduction reaction. The specific operation steps may include: dissolving the reducing agent in concentrated hydrochloric acid to obtain a concentrated hydrochloric acid solution containing the reducing agent; ^{dissolving the 15} ^N -labeled 2,4,6-trihydrochloride Azophenyl-1,3,5-triaminobenzene is dispersed in a third solvent to obtain a reaction system; the reaction system is added to a concentrated hydrochloric acid solution, and a reduction reaction is carried out to obtain the ¹⁵ N-labeled hexaamino group shown in structural formula II Benzene trihydrochloride.

During specific implementation, the reducing agent is tin dichloride; the molar ratio of tin dichloride and ¹⁵ N-labeled 2,4,6-trisazophenyl-1,3,5-triaminobenzene is 7～21: 1; the reaction temperature of the reduction reaction is 85-95° C., and the reaction time is 0.5-3 h; the third solvent includes at least one of tetrahydrofuran, ethyl acetate, chloroform, acetone and methanol.

Step 2 (S102), using ¹⁵ N-labeled hexaaminobenzenetrihydrochloride and cyclohexanone shown in structural formula V as reaction raw materials, and sequentially performing polycondensation reaction, purification, and activation treatment to obtain ¹⁵ N shown in structural formula I and ¹⁴ N interspersed distribution of uniform nitrogen-doped graphene.

In this implementation step, cyclohexanone octahydrate is selected as cyclohexanone; ¹⁵ N-labeled hexaaminobenzenetrihydrochloride and cyclohexanone octahydrate are subjected to a polycondensation reaction under the action of an acidic reagent. Wherein, the acidic reagent includes any one of glacial acetic acid, sulfuric acid and trifluoromethanesulfonic acid; the first solvent used in the polycondensation reaction includes at least methanol, ethanol, acetone, ethyl acetate, chloroform, tetrahydrofuran, acetonitrile and deionized water One; the reaction temperature of the polycondensation reaction is 120-140 DEG C, and the reaction time is 4-6h.

In this implementation step, the molar ratio of cyclohexanone octahydrate to ¹⁵ N-labeled hexaaminobenzenetrihydrochloride is 1-1.1:1.

In this implementation step, the activation treatment is thermal activation treatment, the treatment temperature of the thermal activation treatment is 300-700° C., and the treatment time is 2-4 hours.

In the embodiment of the present invention, the general synthetic route of the uniform nitrogen-doped graphene with the interspersed distribution of ¹⁵ N and ¹⁴ N shown in structural formula I is as follows:

Wherein, R in structural formula II, structural formula III and structural formula IV is the same, and the R= any one of H, CH ₃ , NO ₂ , OCH ₃ , COOH, SO ₃ H, COC ₆ H ₅ , and C(CH ₃ ) ₃ ; In structural formula III, X=any one of Cl, Br, BF ₄ , and PF ₆ .

The embodiment of the present invention provides a novel isotope-labeled synthesis method (that is, a method for preparing uniform nitrogen-doped graphene with ¹⁵ N and ¹⁴ N interspersed distribution), which is labeled with 1,3,5-triaminobenzene and ¹⁵ N Sodium nitrite or potassium nitrite is used as the starting material, and the ¹⁵ N-labeled hexaaminobenzene hydrochloride is prepared through two steps of a diazonium salt coupling reaction and a reduction reaction of an azo compound. There are many choices of aromatic amines, in addition to the most common aniline diazonium salts, diazonium salts with substituted groups on the benzene ring (such as methyl, methoxy, tert-butyl, nitro, acetyl, acetamide) group, sulfonic acid group, carboxyl group, etc.) can also be used in the coupling reaction. The 1,3,5-triaminobenzene solution is dropped into the diazonium salt solution, and the coupling reaction occurs rapidly. The coupling reaction can be carried out at low temperature or normal temperature. The reaction time is extremely fast, and the separation and post-processing are easy. The azo bond can be cut into amino groups by moderately active reducing agents (tin dichloride, sodium thiosulfate, etc.). reducing agent. The dehydration reaction of ¹⁵ N-labeled hexaaminobenzene hydrochloride and cyclohexanone was catalyzed by glacial acetic acid to prepare uniform nitrogen-doped graphene with interspersed distribution of ¹⁵ N and ¹⁴ N.

In the actual operation process, the moderately active reducing agent may also be a reducing agent commonly used in the prior art, such as H ₂ -Raney Ni, H ₂ -Pd/C, Fe/HCl, Zn/HCl and the like. Among them, when catalytic hydrogenation is carried out, acidification should be carried out immediately after catalytic hydrogenation.

In this embodiment, when the reduction system is H ₂ -Raney Ni or H ₂ -Pd/C, in the specific operation process, a sufficient amount of hydrogen may be sufficient, which is not particularly limited. The addition amount of the catalyst ( ^Raney Ni or Pd/C) can also be added according to actual needs. The mass ratio of 5-triaminobenzene is 0.05～0.2:1;

When the reduction system is Fe/HCl or Zn/HCl, the addition amount of iron powder or zinc powder can also be added according to actual needs. In this embodiment, iron powder or zinc powder and ¹⁵ N labeled 2,4,6 -The molar ratio of trisazo-p-acetophenyl-1,3,5-triaminobenzene can be 6-18:1, and the dosage of concentrated hydrochloric acid can be 4-8ml.

The uniform nitrogen-doped graphene with ¹⁵ N and ¹⁴ N interspersed distribution prepared by the embodiment of the present invention provides a large number of detectable signals by virtue of the ¹⁵ N atoms with periodic uniform distribution inside, which solves the problem that the structure of C ₂ N materials is difficult to characterize of inadequacies.

In order for those skilled in the art to better understand the present invention, the following describes the preparation method of uniform nitrogen-doped graphene with interspersed distribution of ¹⁵ N and ¹⁴ N provided by the present invention through a plurality of specific embodiments.

Example 1

Step 1: Synthesis of ¹⁵ N-labeled 2,4,6-trisazophenyl-1,3,5-triaminobenzene

¹⁵ N-labeled sodium nitrite (Na ¹⁵ NO ₂ , 220.2 mg, 3.1 mmol, 3.1 eq) was dissolved in 30 ml of deionized water, placed in an ice bath for pre-cooling for 10 min; concentrated hydrochloric acid (3.2 ml) was mixed with deionized water (100ml) mixed uniformly, placed in ice-water mixture for pre-cooling, dropwise added aniline (0.27ml, 1mmol, 1eq), mixed uniformly by magnetic stirring, then slowly added 30ml Na ¹⁵ NO ₂ aqueous solution, and reacted under magnetic stirring After 30 min, add saturated sodium carbonate solution to adjust the pH value to neutral or weakly alkaline.

After the reaction, 1,3,5-triaminobenzene hydrochloride (232.7 mg, 1 mmol, 1 eq) and sodium carbonate (320 mg, 3 mmol, 3 eq) were dissolved in 30 ml of deionized water. Then, the 1,3,5-triaminobenzene aqueous solution was slowly dropped into the aqueous solution of diazobenzene hydrochloride under magnetic stirring, and the dropwise addition was completed and stirred for 30 min. After the reaction, the orange flocculent precipitate was obtained by filtration, washed with water and dried to obtain ¹⁵ N-labeled

compound

2,4,6-trisazophenyl-1,3,5-triaminobenzene (300.0 mg, 68.4%) .

Referring to Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7 and Fig. 8, the intermediate product ¹⁵ N-labeled 2,4,6-triazophenyl-1,3 in Example 1 of the present invention is shown , Solution H NMR spectrum, solution C NMR spectrum, solution N NMR spectrum, solid C NMR spectrum, solid N NMR spectrum, high resolution mass spectrum and Fourier transform of 5-triaminobenzene Infrared spectra.

^1H -NMR (400MHz, DMSO-D6) δ(ppm): 9.59(s, NH, 6H), 7.89(d, J=7.6Hz, Ar-H, 6H), 7.52(t , J=7.6Hz, Ar-H, 6H), 7.36 (t, J=7.2Hz, Ar-H, 3H).

Solution carbon nuclear magnetic resonance spectrum Figure ¹³ C-NMR (101 MHz, DMSO-D6): δ (ppm): 152.62, 129.12, 127.96, 121.18, 113.40.

Solution ¹⁵ N-NMR (40.5 MHz, DMSO-D6): δ (ppm): 88.81 (CH ₃ NO ₂ : 0 ppm).

Solid-state carbon nuclear magnetic resonance spectrum Figure ¹³ C-NMR (101 MHz, CP/MAS): δ (ppm): 151.17, 145.73, 139.96, 126.72, 125.43, 112.46.

Solid-state nuclear magnetic resonance nitrogen spectrum ¹⁵ N-NMR (40.5 MHz, CP/MAS): δ (ppm): 140.72 (glycine: ppm).

High-resolution mass spectrum MS (ESI): m/z 439.19126 (M+H ⁺ , required 439.19037).

FT-IR (ATR, cm ^-1 ): 3503(w), 3432(w), 3384(w), 3183(w), 1571(s), 1521(m), 1479(m), 1454 (m), 1344(s), 1304(m), 1199(w), 1114(m), 1070(w), 1020(w), 911(m), 760(s), 687(m), 591 (m), 520 (m).

Step 2: Synthesis of ¹⁵ N-labeled hexaaminobenzene hydrochloride

Tin dichloride (1.9g, 10mmol, 10eq) was completely dissolved in concentrated hydrochloric acid (5ml), and then ^15N -labeled 2,4,6-triazophenyl-1,3,5-triaminobenzene ( 450.2 mg, 1 mmol, 1 eq) were dispersed in ethyl acetate (20 ml). The ethyl acetate solution was added dropwise to the concentrated hydrochloric acid solution of SnCl ₂ stirred on a magnetic stirrer, heated under reflux at 95 °C for 2 h to ensure complete reaction, a pale pink precipitate appeared in the system, and the liquid color changed from orange-red to close to in pale yellow. After suction filtration, the solid was washed with 20 ml of ethyl acetate and methanol, respectively, and dried to obtain ¹⁵ N-labeled hexaaminobenzenetrihydrochloride as a powdery solid (200.3 mg, yield 71.4%).

Referring to Fig. 9, Fig. 10, Fig. 11, Fig. 12 and Fig. 13, the solution H NMR spectra and solid C NMR spectra of the intermediate product ¹⁵ N-labeled hexaaminobenzene trihydrochloride in Example 1 of the present invention are shown , solid-state nuclear magnetic resonance nitrogen spectrum, high-resolution mass spectrum and Fourier transform infrared spectrum.

¹ H-NMR (400MHz, DMSO-d6)δ(ppm): 6.00～10.00(s, NH _, 12H).

Solid-state carbon nuclear magnetic resonance spectrum Figure ¹³ C-NMR (101 MHz, CP/MAS): δ (ppm): 132.39, 90.56.

Solid-state nuclear magnetic resonance nitrogen spectrum Figure ¹⁵ N-NMR (40.5 MHz, CP/MAS): δ (ppm): 52.30, 45.13 (glycine: ppm).

High resolution mass spectrum MS (ESI): m/z 172.11054 (M-3HCl+H ⁺ , required: 172.11072).

FT-IR (ATR, cm ^-1 ): 3353(m), 3223(m), 2892(s), 2607(m), 1667(w), 1624(m), 1529(s), 1490 (s), 1199(w), 1105(w), 742(w), 687(w).

Step 3: Facile Synthesis of Uniform Nitrogen-Doped Graphene Interspersed with ^15N and ^14N

Dissolve or disperse ¹⁵ N-labeled hexaaminobenzenetrihydrochloride (280mg, 1mmol, 1eq) and cyclohexanehexanone octahydrate (320mg, 1mmol, 1eq) in ethanol (5ml)/glacial acetic acid (5ml) and mix In the liquid, heated to reflux at 120 ℃ for 4 hours, black precipitate appeared in the system, some solids adhered to the wall of the container, and the color of the liquid changed from gray to dark brown. After the reaction, it was cooled to room temperature, and the solid was washed with ethanol and water after filtration, and freeze-dried at -40° C. to finally obtain a black graphite-like solid (278.5 mg).

14 , 15 , 16 , 17 , 18 , 19 , 20 and 21 show the uniform nitrogen-doped graphene material with interspersed distribution of intermediate products ¹⁵ N and ¹⁴ N in Example 1 of the present invention. Solid carbon NMR spectrum, solid NMR nitrogen spectrum, Fourier transform infrared spectrum, Raman spectrum, powder X-ray diffraction, X-ray photoelectron spectrum, scanning electron microscope and transmission electron microscope.

Solid-state carbon nuclear magnetic resonance spectrum Figure ¹³ C-NMR (101 MHz, CP/MAS): δ (ppm): 128.45.

Solid-state nuclear magnetic resonance nitrogen spectrum ¹⁵ N-NMR (40.5 MHz, CP/MAS): δ (ppm): 153.50 (glycine: 32 ppm). .

FT-IR (ATR, cm ^-1 ): 3179(m), 2989(m), 1619(s), 1500(s), 1370(s), 1276(s), 1066(s).

Elemental analysis (%): C, 58.09; H, 1.88; N, 28.33.

Example 2

Step 1: Synthesis of ¹⁵ N-labeled hexaaminobenzene hydrochloride

Step 1 of the present embodiment is similar to the preparation method of

steps

1 and 2 of Example 1, with the following differences:

R=CH ₃ in the substituted aniline used, when carrying out the diazotization reaction, the molar ratio of ¹⁵ N-labeled potassium nitrite and the substituted aniline is 1:1, the reaction temperature of the diazotization reaction is -5°C, and the reaction time is for 10min; when the coupling reaction is carried out, the molar ratio of ¹⁵ N-labeled diazonium salt and 1,3,5-triaminobenzene hydrochloride is 3:1; the alkaline reagent added to construct the alkaline condition is hydroxide sodium, the reaction temperature of the coupling reaction is -5°C, and the reaction time is 15 min; the second solvent used in the coupling reaction is methanol.

The molar ratio of tin dichloride to ¹⁵ N-labeled 2,4,6-triazo-p-tolyl-1,3,5-triaminobenzene was 7:1; the reaction temperature was 85°C, and the reaction time was 0.5h ; The third solvent used is tetrahydrofuran.

The powdered solid of ¹⁵ N-labeled hexaaminobenzene hydrochloride obtained in this implementation step was 205.6 mg, and the yield was 73.3%. The solution hydrogen nuclear magnetic resonance spectrum, solid carbon nuclear magnetic resonance spectrum, solid nitrogen nuclear magnetic resonance spectrum, high-resolution mass spectrum and Fourier transform infrared spectrum of the ¹⁵ N-labeled hexaaminobenzene hydrochloride prepared in the implementation steps of the present invention , which are respectively the same as those in FIG. 9 , FIG. 10 , FIG. 11 , FIG. 12 and FIG. 13 , and are not repeated in this implementation step.

Step 2: Facile Synthesis of Uniform Nitrogen-Doped Graphene Interspersed with ^15N and ^14N

Step 2 of the present embodiment is similar to the preparation method of step 3 of Example 1, with the following differences:

The acidic reagent is glacial acetic acid, the first solvent used in the polycondensation reaction is methanol, the reaction temperature of the polycondensation reaction is 130 ° C, and the reaction time is ⁵ h; The molar ratio is 1:1.

The uniform nitrogen-doped graphene with interspersed distribution of ¹⁵ N and ¹⁴ N obtained in this implementation step is 275.6 mg. The solid carbon nuclear magnetic resonance spectrum, solid nuclear magnetic ^resonance nitrogen spectrum, ^Fourier infrared spectrum, Raman spectrum, powder X The ray diffraction pattern, X-ray photoelectron spectrum pattern, scanning electron microscope pattern and transmission electron microscope pattern are the same as those of Fig. 14, Fig. 15, Fig. 16, Fig. 17, Fig. 18, Fig. 19, Fig. 20 and Fig. 21 respectively. The steps are not repeated.

In this implementation step, the operation of thermal activation treatment is as follows:

500 mg of the prepared uniform nitrogen-doped graphene interspersed with ¹⁵ N and ¹⁴ N was ground into powder and heated at 400 °C for 2 h in an argon atmosphere. After completion of the reaction, the reaction was cooled to room temperature, and finally a black graphite-like solid (286.7 mg) was obtained.

Referring to FIG. 22 , FIG. 23 and FIG. 24 show the solid-state carbon NMR spectrum, Fourier transform infrared spectrum and scanning of uniform nitrogen-doped graphene with ¹⁵ N and ¹⁴ N interspersed distribution prepared in Example 2 of the present invention Electron microscope image.

Solid-state carbon nuclear magnetic resonance spectrum Figure ¹³ C-NMR (101 MHz, CP/MAS): δ (ppm): 139.75.

FT-IR (ATR, cm ^-1 ): 3175(w), 2222(w), 1613(s), 1493(s), 1366(s), 1229(s).

Elemental analysis (%): C, 53.44; H, 1.86; N, 34.52.

Example 3

Step 1: Synthesis of ¹⁵ N-labeled hexaaminobenzene hydrochloride

Step 1 of the present embodiment is similar to the preparation method of

steps

1 and 2 of Example 1, with the following differences:

R=NO ₂ in the substituted aniline used, when carrying out the diazotization reaction, the molar ratio of ¹⁵ N-labeled sodium nitrite to the substituted aniline is 1.1:1, the reaction temperature of the diazotization reaction is -5°C, and the reaction time is for 20min; when the coupling reaction is carried out, the molar ratio of ¹⁵ N-labeled diazonium salt and 1,3,5-triaminobenzene hydrochloride is 3.5:1; the alkaline reagent added to construct basic conditions is hydroxide Potassium, the reaction temperature of the coupling reaction is 15°C, and the reaction time is 60 min; the second solvent used in the coupling reaction is acetone.

The molar ratio of tin dichloride to ¹⁵ N-labeled 2,4,6-triazo-p-nitrophenyl-1,3,5-triaminobenzene was 15:1; the reaction temperature was 90°C, and the reaction time was 1 h; the third solvent used was chloroform.

The powdered solid of ¹⁵ N-labeled hexaaminobenzene hydrochloride obtained in this implementation step was 170.7 mg, and the yield was 60.9%. The solution hydrogen nuclear magnetic resonance spectrum, solid carbon nuclear magnetic resonance spectrum, solid nitrogen nuclear magnetic resonance spectrum, high-resolution mass spectrum and Fourier transform infrared spectrum of the ¹⁵ N-labeled hexaaminobenzene hydrochloride prepared in the implementation steps of the present invention , which are respectively the same as those in FIG. 9 , FIG. 10 , FIG. 11 , FIG. 12 and FIG. 13 , and are not repeated in this implementation step.

Step 2 of this embodiment is similar to the preparation method of step 3 of Example 1, except that the acid reagent is sulfuric acid, the first solvent used in the polycondensation reaction is acetone, the reaction temperature of the polycondensation reaction is 120° C., and the reaction time is 4h; the molar ratio of cyclohexanone octahydrate to 15N-labeled hexaaminobenzenetrihydrochloride is 1.1:1.

The uniform nitrogen-doped graphene with interspersed distribution of ¹⁵ N and ¹⁴ N obtained in this implementation step is 283.7 mg. The solid carbon nuclear magnetic resonance spectrum, solid nuclear magnetic ^resonance nitrogen spectrum, ^Fourier infrared spectrum, Raman spectrum, powder X The ray diffraction pattern, X-ray photoelectron spectrum pattern, scanning electron microscope pattern and transmission electron microscope pattern are the same as those of Fig. 14, Fig. 15, Fig. 16, Fig. 17, Fig. 18, Fig. 19, Fig. 20 and Fig. 21 respectively. The steps are not repeated.

500 mg of uniform nitrogen-doped graphene interspersed with ¹⁵ N and ¹⁴ N was ground into powder and heated at 500 °C for 2 h in an argon atmosphere. After completion of the reaction, the reaction was cooled to room temperature, and finally a black graphite-like solid (292.4 mg) was obtained.

Referring to FIG. 25 , FIG. 26 and FIG. 27 show the solid-state carbon NMR spectrum and Fourier transform infrared spectrum of uniform nitrogen-doped graphene with ¹⁵ N and ¹⁴ N interspersed distribution of the intermediate product ¹⁵ N in Example 3 of the present invention Figure, Raman spectrum, powder X-ray diffraction and X-ray photoelectron spectroscopy.

Solid-state carbon nuclear magnetic resonance spectrum Figure ¹³ C-NMR (101 MHz, CP/MAS): δ (ppm): 133.80, 124.06.

FT-IR (ATR, cm ^-1 ): 2988(w), 2209(w), 1488(s), 1227(s).

Elemental analysis (%): C, 58.19; H, 1.85; N, 32.56.

Example 4

Step 1: Synthesis of ¹⁵ N-labeled hexaaminobenzene hydrochloride

Step 1 of this example is similar to the preparation method of

steps

1 and 2 of Example 1, the difference is: in the substituted aniline used, R=COCH ₃ , when carrying out the diazotization reaction, ¹⁵ N-labeled sodium nitrite The molar ratio to substituted aniline is 1.1:1, the reaction temperature of the diazotization reaction is 5°C, and the reaction time is 30min; when the coupling reaction is carried out, the ¹⁵ N-labeled diazonium salt and 1,3,5-triamino The molar ratio of benzene hydrochloride was 4:1; the basic reagent added to construct basic conditions was potassium carbonate, the reaction temperature of the coupling reaction was 25°C, and the reaction time was 120 min.

The molar ratio of tin dichloride to ¹⁵ N-labeled 2,4,6-triazo-p-acetophenyl-1,3,5-triaminobenzene was 21:1; the reaction temperature was 95°C, and the reaction time was 3h ; The third solvent used is methanol.

The powdered solid of ¹⁵ N-labeled hexaaminobenzene hydrochloride obtained in this implementation step was 203.8 mg, and the yield was 72.7%. The solution hydrogen nuclear magnetic resonance spectrum, solid carbon nuclear magnetic resonance spectrum, solid nitrogen nuclear magnetic resonance spectrum, high-resolution mass spectrum and Fourier transform infrared spectrum of the ¹⁵ N-labeled hexaaminobenzene hydrochloride prepared in the implementation steps of the present invention , which are respectively the same as those in FIG. 9 , FIG. 10 , FIG. 11 , FIG. 12 and FIG. 13 , and are not repeated in this implementation step.

Step 2: Facile Synthesis of Nitrogen-Doped Graphene Materials with Uniform Interleaving of ^15N and ^14N

Step 3 of this embodiment is similar to the preparation method of step 3 of Example 1, except that the acid reagent is sulfuric acid, the first solvent used in the polycondensation reaction is acetonitrile, the reaction temperature of the polycondensation reaction is 140° C., and the reaction time is 6h.

The uniform nitrogen-doped graphene with interspersed distribution of ¹⁵ N and ¹⁴ N obtained in this implementation step is 276.4 mg. The solid carbon nuclear magnetic resonance spectrum, solid nuclear magnetic ^resonance nitrogen spectrum, ^Fourier infrared spectrum, Raman spectrum, powder X The ray diffraction pattern, X-ray photoelectron spectrum pattern, scanning electron microscope pattern and transmission electron microscope pattern are the same as those of Fig. 14, Fig. 15, Fig. 16, Fig. 17, Fig. 18, Fig. 19, Fig. 20 and Fig. 21 respectively. The steps are not repeated.

500 mg of uniform nitrogen-doped graphene interspersed with ¹⁵ N and ¹⁴ N was ground into powder and heated at 600 °C for 2 h in an argon atmosphere. After the reaction was completed, the reaction was cooled to room temperature, and finally a black graphite-like solid (283.1 mg) was obtained.

Referring to FIG. 28 , FIG. 29 and FIG. 30 show the solid-state carbon NMR spectrum, Fourier transform infrared spectrum and scanning of uniform nitrogen-doped graphene with ¹⁵ N and ¹⁴ N interspersed distribution of the intermediate product of Example 4 of the present invention Electron microscope image.

Solid-state carbon nuclear magnetic resonance spectrum Figure ¹³ C-NMR (101 MHz, CP/MAS): δ (ppm): 138.82, 130.48.

FT-IR (ATR, cm ^-1 ): 3171(w), 2218(w), 1472(s), 1235(s).

Elemental analysis (%): C, 49.36; H, 1.35; N, 32.61.

Example 5

The

steps

1 and 2 of the present embodiment are similar to the preparation methods of the

steps

1 and 2 of the embodiment 1, and the differences are:

In step 2, the reduction system is H ₂ -Pd/C. Among them, hydrogen is sufficient; the mass ratio of Pd/C catalyst to ¹⁵ N-labeled 2,4,6-triazo-p-acetophenyl-1,3,5-triaminobenzene is 0.1:1. The specific use method of the reduction system in the operation process in this embodiment is as follows.

Take ¹⁵ N-labeled 2,4,6-triazo-p-acetophenyl-1,3,5-triaminobenzene (0.5g, 1mmol, 1eq) and dissolve it in ethyl acetate (30ml) to obtain a solution, in Pd/ In the presence of catalyst C (0.1g), carry out high-pressure hydrogenation reaction, after airtight, carry out three cycles of nitrogen filling and degassing to eliminate the influence of system air as much as possible, introduce hydrogen (within 0.4MPa), and use magnetic stirrer or mechanical stirrer to continue stirring, The reaction temperature in the kettle was controlled within 50°C. Control the introduction of hydrogen at a certain time interval to observe the pressure indicator to judge the progress of the reaction. When the pressure indication no longer changes significantly after 20 minutes of stopping the introduction of hydrogen, it is regarded as the end point of the reaction. After discharging part of the hydrogen, carry out three cycles of nitrogen filling and degassing again, and open the kettle to filter to obtain a hexaaminobenzene solution. Excess concentrated hydrochloric acid (10 ml) was slowly added to the solution, and after precipitation, filtration, washing and drying were performed to obtain the target product.

The powdered solid of ¹⁵ N-labeled hexaaminobenzene hydrochloride obtained in this implementation step was 203.8 mg, and the yield was 72.7%. The solution hydrogen nuclear magnetic resonance spectrum, solid carbon nuclear magnetic resonance spectrum, solid nitrogen nuclear magnetic resonance spectrum, high-resolution mass spectrum and Fourier transform infrared spectrum of the ¹⁵ N-labeled hexaaminobenzene hydrochloride prepared in the implementation steps of the present invention , which are respectively the same as those in FIG. 9 , FIG. 10 , FIG. 11 , FIG. 12 and FIG. 13 , and are not repeated in this implementation step. .

Step 3: Preparation of uniform nitrogen-doped graphene with interspersed distribution of ¹⁵ N and ¹⁴ N.

Step 3 of this embodiment is similar to the preparation method of step 3 of embodiment 1, and the difference is the operation of thermal activation treatment, as follows:

500 mg of uniform nitrogen-doped graphene interspersed with ¹⁵ N and ¹⁴ N was ground into powder and heated at 700 °C for 2 h in an argon atmosphere. After completion of the reaction, the reaction was cooled to room temperature, and finally a black graphite-like solid (291.4 mg) was obtained.

Referring to Fig. 31, Fig. 32, Fig. 33 and Fig. 34, the solid-state carbon NMR spectrum and Fourier transform infrared spectrum of uniform nitrogen-doped graphene with interspersed distribution of intermediate products ¹⁵ N and ¹⁴ N in Example 5 of the present invention are shown , Scanning Electron Microscopy and Transmission Electron Microscopy.

Solid-state carbon nuclear magnetic resonance spectrum Figure ¹³ C-NMR (101 MHz, CP/MAS): δ (ppm): 133.75, 110.11.

FT-IR (ATR, cm ^-1 ): 2210(w), 1495(s), 1219(s).

Elemental analysis (%): C, 58.78; H, 1.14; N, 35.69.

Example 6

Step 1, step 2 and step 3 of this embodiment are similar to the preparation method of step 1, step 2 and step 3 of embodiment 1, and the differences are:

In step 2, Fe/HCl is selected as the reduction system. Wherein, the molar ratio of iron powder and ¹⁵ N-labeled 2,4,6-triazo-p-acetophenyl-1,3,5-triaminobenzene is 6:1; the amount of concentrated hydrochloric acid is 4ml. It should be noted that, regarding the specific use method of the reduction system in the operation process in this embodiment, conventional operations may be adopted.

The ^solid -state carbon NMR spectrum, Fourier transform infrared spectrum, ^Raman spectrum, ^powder X-ray diffractogram and The X-ray photoelectron spectrograms are respectively the same as those in FIG. 14 , FIG. 16 , FIG. 17 , FIG. 18 and FIG. 19 , and will not be repeated in this implementation step.

It should be noted that the steps and methods in the various embodiments of the present application are not limited to the corresponding embodiments, and the operation details and precautions of the various embodiments are corresponding to each other. The value range of each substance and the value range of each parameter are only the preferred solutions of the present invention, and the present invention does not limit the value range, and any value range applicable to the present invention is feasible.

In a third aspect, the present invention provides an application of uniform nitrogen-doped graphene with ¹⁵ N and ¹⁴ N interspersed distribution, the application may be: ¹⁵ N and ¹⁴ N interspersed and distributed uniform nitrogen-doped graphene prepared in the second aspect above Heterographene is used in the preparation of graphene materials or modified graphene materials, characterization or detection of physical and chemical properties of graphene materials or modified graphene materials, precise chemical structure characterization of uniform nitrogen-doped graphene porous materials, intrinsic physical properties Research on chemical properties, gas adsorption separation and its mechanism research, and single-atom catalysis mechanism research and other related fields.

In order for those skilled in the art to better understand the present invention, the application of the uniform nitrogen-doped graphene material provided by the present invention with interspersed distribution of ¹⁵ N and ¹⁴ N provided by the present invention will be illustrated by a plurality of specific embodiments.

Example 7: Thermal stability of uniform nitrogen-doped graphene material with ¹⁵ N and ¹⁴ N interspersed distribution:

In the embodiment of the present invention, the uniform nitrogen-doped graphene material with ¹⁵ N and ¹⁴ N interspersed and distributed prepared in the above embodiment 2 has good thermal stability, which is beneficial to the popularization and application of the material. In the embodiment of the present invention, the synthesized uniform nitrogen-doped graphene material with interspersed distribution of ¹⁵ N and ¹⁴ N and thermally activated products at different temperatures are characterized.

Thermogravimetric Analysis (TGA) refers to a thermal analysis technique that measures the relationship between the mass of the sample to be tested and the temperature change at a programmed temperature. It is used to study the thermal stability and composition of the material, and the thermal Thermal performance information resulting from changes. Thermal stability performance reflects whether the material can maintain stable properties under heating.

Referring to FIG. 35 , a thermogravimetric analysis diagram of the nitrogen-doped graphene material in which the intermediate products ¹⁵ N and ¹⁴ N of Example 7 of the present invention are uniformly interspersed and distributed is shown.

The uniform nitrogen-doped graphene porous material with ¹⁵ N and ¹⁴ N interspersed distribution begins to decrease in quality when the temperature is higher than 200 °C, and shows a multi-stage degradation phenomenon. First, the degradation in the first stage at 200°C-280°C was obvious and the mass loss was about 15%, and the loss rate reached the highest at 218°C. The degradation rate of the second stage at 280°C-360°C is slow, and the mass loss is about 10%, and the loss rate is higher at 334°C. These two stages are due to the deep polycondensation of the oligomers, resulting in the residual hydrogen and oxygen atoms leaving the system in the form of water. The degradation after 400 °C in the third stage is caused by the loss of C and N atoms, and the degradation rate is slow. To sum up, the nitrogen-doped graphene material with ¹⁵ N and ¹⁴ N evenly interspersed and distributed can ensure sufficient polycondensation above 400 °C, so the thermal activation temperature should be set above 400 °C. The thermally activated nitrogen-doped graphene material has good thermal stability, which is conducive to the popularization and application of the material in harsh environments such as high temperature.

Example 8: Comparative characterization of uniform nitrogen-doped graphene material with ¹⁵ N and ¹⁴ N interspersed distribution and non-labeled material:

In the embodiment of the present invention, the uniform nitrogen-doped graphene with interspersed distribution ^of15N ^and14N prepared in the above Example 2, with a large number of stably ^labeled15N isotopes, it is found by comparison that nuclear magnetic resonance spectroscopy is effective ^for15N labeled materials The identification of the characterization is much higher than that of non-labeled materials.

Referring to Figure 36, Figure 37 and Figure 38, the Fourier analysis of N-labeled and non-labeled 2,4,6-trisazophenyl-1,3,5-triaminobenzene of the intermediate product ¹⁵ of Example 7 of the present invention is shown Leaf infrared spectrum comparison chart, high-resolution mass spectrometry comparison chart, and solid-state nuclear magnetic resonance nitrogen spectrum comparison chart; with reference to Figure 39, Figure 40 and Figure 41, it shows the ¹⁵ N-labeled and non-labeled hexaaminobenzene of the intermediate product of Example 8 of the present invention. Fourier infrared spectrum comparison chart, high-resolution mass spectrometry comparison chart, and solid-state nuclear magnetic resonance nitrogen spectrum comparison chart; with reference to FIG. 42 and FIG. 43 , the uniform nitrogen doping with interspersed distribution of ¹⁵ N and ¹⁴ N in the intermediate product of Example 8 of the present invention is shown Comparison of Fourier transform infrared spectra and solid-state NMR spectra of graphene materials and non-labeled materials.

By comparing the infrared spectra of the labeled and unlabeled precursor small molecules and nitrogen-doped graphene materials, we found that the spectral shapes of the labeled and unlabeled products are basically the same, indicating that the labeled and unlabeled substances have no obvious functional group structure. It can be deduced that the introduction of ¹⁵ N isotope has no adverse effect on the reactivity.

The introduction of ¹⁵ N can be visualized by high-resolution mass spectrometry and solid-state NMR spectroscopy. We compared the high-resolution mass spectra of ¹⁵ N-labeled and unlabeled 2,4,6-trisazophenyl-1,3,5-triaminobenzene and hexaaminobenzene and found that their molecular ion peaks represent the mass-to-charge ratios The difference is 3, which is in line with the reaction expectation, confirming that the ¹⁵ N atom is indeed inserted into the vacant site of the

reactant

1,3,5-triaminobenzene. Since nuclear magnetic resonance spectroscopy has extremely high sensitivity for the detection of ¹⁵ N isotope, but basically has no detection activity for the ¹⁴ N isotope, comparing the ¹⁵ N-labeled and unlabeled 2,4,6-triazophenyl-1,3,5 -The effect of solid-state NMR nitrogen spectrum of triaminobenzene, hexaaminobenzene and nitrogen-doped graphene materials is more prominent. Under the same conditions, characteristic peaks appeared quickly in the NMR spectra of the three labeled samples, and perfect spectra were obtained after 128 scans (the test time was about 1h), but the unlabeled samples were scanned tens of thousands of times (the test time was about 1d). ), still no characteristic peaks appear. It can be seen that the introduction of ¹⁵ N provides a lot of convenience for NMR characterization.

In summary, the characterization and detection activity of uniform nitrogen-doped graphene with ^15N and ^14N interspersed distribution is much higher than that of non-labeled nitrogen-doped graphene materials. It is expected to use advanced nuclear magnetic technology to observe ^15N isotope atoms and other guests in the future. The binding of molecules provides intuitive and visible experimental evidence.

Example 9: Characterization of porous properties of uniform nitrogen-doped graphene with interspersed distribution of ¹⁵ N and ¹⁴ N:

In the embodiment of the present invention, the uniform nitrogen-doped graphene with ¹⁵ N and ¹⁴ N interspersed and distributed prepared in the above Example 2, after being activated by heat treatment, has excellent properties such as high specific surface area and abundant pore structure, and has potential application prospects. The examples of the present invention are represented by uniform nitrogen-doped graphene with interspersed distribution of ¹⁵ N and ¹⁴ N after heat treatment at 700°C, the porous properties of such materials are characterized, and their main application directions are described.

The evaluation parameter of porous performance-specific surface area is usually measured by gas adsorption _- desorption isotherm method. The adsorption isotherms were obtained. After that, many important parameters such as BET specific surface area, pore volume and pore size distribution were calculated from the BET model.

Referring to FIG. 44 , the pore size distribution curve calculated by NLDFT of C ₂ N-700 prepared in Example 5 of the present invention is shown.

The specific surface area and pore volume values of the C ₂ N-700 prepared in Example 5 of the present invention are shown in the following table:

The uniform nitrogen-doped graphene with ^15N and ^14N interspersed distribution prepared by the present invention is prepared by a simple, efficient and environmentally friendly method. Large specific surface area, large total pore volume and relatively small average pore size will play an important role in metal ion complexation, organic pollutant adsorption, and gas storage and other fields related to the environment and energy.

Example 10: Characterization of adsorption performance of uniform nitrogen-doped graphene with interspersed distribution of ¹⁵ N and ¹⁴ N:

In the embodiment of the present invention, the uniform nitrogen-doped graphene with ¹⁵ N and ¹⁴ N interspersed and distributed prepared in the above embodiment 2 provides a large number of fixed sites due to the periodic distribution of nitrogen atoms in the interior, which can be combined with protic solvents, Substances such as metal ions and acid gases have potential binding capabilities. Based on the introduction of a large number of ¹⁵ N isotopes, the difficulty of material characterization and detection is reduced, and the combination of nitrogen-doped graphene materials and adsorbates can be visually displayed. The embodiments of the present invention are represented by uniform nitrogen-doped graphene with interspersed distribution of ¹⁵ N and ¹⁴ N. The adsorption properties of such materials for metal ions and CO ₂ gas are characterized, and their main application directions are described.

The method embodiments are described as a series of action combinations for the sake of simple description, but those skilled in the art should know that the present invention is not limited by the described action sequence, because according to the present invention, some steps Other sequences or concurrently may be used. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and components involved are not necessarily required by the present invention.

A kind of uniform nitrogen-doped graphene with interspersed distribution of ¹⁵ N and ¹⁴ N provided by the present invention and its preparation method and application have been introduced in detail above. In this paper, specific examples are used to illustrate the principle and implementation of the present invention. The description of the above embodiment is only used to help understand the method of the present invention and its core idea; meanwhile, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in specific embodiments and application scope, In conclusion, the contents of this specification should not be construed as limiting the present invention.

In the description provided herein, numerous specific details are set forth. It will be understood, however, that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that it can still be The technical solutions described in the foregoing embodiments are modified, or some technical features thereof are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

A uniform nitrogen-doped graphene with 15 N and 14 N interspersed and distributed, characterized in that the uniform nitrogen-doped graphene with 15 N and 14 N interspersed and distributed is hexaaminobenzene with 15 N and 14 N interspersed and distributed Hydrochloride is a reactant, prepared by polycondensation;

The repeating structural unit in the uniform nitrogen-doped graphene structure interspersed with 15 N and 14 N is the structure shown in the following structural formula I, and the structure of the hexaaminobenzene hydrochloride interspersed with 15 N and 14 N It is the structure shown by the following structural formula II:

Among them, 15 N and 14 N are uniformly interspersed and distributed in structural formula I.
A method for preparing uniform nitrogen-doped graphene with 15N and 14N interspersed distribution according to claim 1, characterized in that, the method comprises:

Step 1, using 15 N-labeled sodium nitrite or potassium nitrite, substituted aniline shown in structural formula III and 1,3,5-triaminobenzene hydrochloride shown in structural formula IV as reaction raw materials, successively through coupling reaction , the reduction reaction prepares the hexaaminobenzene trihydrochloride of the 15 N label;

Step 2, using the 15 N-labeled hexaaminobenzenetrihydrochloride and cyclohexanone as reaction raw materials, and performing polycondensation reaction, purification, and activation treatment in sequence to obtain the uniform nitrogen-doped 15 N and 14 N interspersed distribution. heterographene;

Wherein, in the structural formula III, R= any one of H, CH 3 , NO 2 , OCH 3 , COOH, SO 3 H, COC 6 H 5 , and C(CH 3 ) 3 .
The method according to claim 2, wherein the cyclohexanone is selected from cyclohexanone octahydrate; the cyclohexanone octahydrate and the 15 N-labeled hexaaminobenzene trihydrochloride are selected. The molar ratio of 1 to 1.1:1.
The method according to claim 3, wherein the polycondensation reaction is carried out under the action of an acidic reagent;

The acidic reagent includes any one of glacial acetic acid, sulfuric acid and trifluoromethanesulfonic acid; the first solvent used in the polycondensation reaction includes methanol, ethanol, acetone, ethyl acetate, chloroform, tetrahydrofuran, acetonitrile and deionized water at least one of;

The reaction temperature of the polycondensation reaction is 120-140° C., and the reaction time is 4-6 h.
The method according to claim 2, wherein the activation treatment is thermal activation treatment, the treatment temperature of the thermal activation treatment is 300-700°C, and the treatment time is 2-4 hours.
The method according to claim 2, wherein the specific operation of step 1 comprises:

Step 1-1, adopting a one-pot method, first using 15 N-labeled sodium nitrite or potassium nitrite and the substituted aniline as raw materials, and preparing the 15 N-labeled diazonium salt shown in structural formula V through a diazotization reaction , and then using the 15 N-labeled diazonium salt and the 1,3,5-triaminobenzene hydrochloride as raw materials, the 15 N-labeled 2,4,6 shown in structural formula VI is prepared through a coupling reaction - Trisazophenyl-1,3,5-triaminobenzene;

In step 1-2, using the 15 N-labeled 2,4,6-trisazophenyl-1,3,5-triaminobenzene as a reactant, the 15 N-labeled hexaaminobenzene is prepared by a reduction reaction Benzene trihydrochloride;

Wherein, R in the structural formula V and structural formula VI is the same as R in the structural formula III; in the structural formula V, X=any one of Cl, Br, BF 4 , and PF 6 .
The method according to claim 6, wherein, in the step 1-1, when the diazotization reaction is performed, the 15 N-labeled sodium nitrite or potassium nitrite and the substituted aniline are The molar ratio is 1～1.1:1;

The reaction temperature of the diazotization reaction is -5 to 5° C., and the reaction time is 10 to 30 minutes.
The method according to claim 6, wherein, in the step 1-1, when the coupling reaction is performed, the 15 N-labeled diazonium salt and the 1,3,5-triamino The molar ratio of benzene hydrochloride is 3～4:1;

The reaction conditions of the coupling reaction are alkaline conditions, and the alkaline reagents to be added to construct the alkaline conditions include any one of sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate;

The reaction temperature of the coupling reaction is -5～25°C, and the reaction time is 15～120min;

The second solvent used in the coupling reaction includes at least one of methanol, ethanol, acetone, ethyl acetate, chloroform, tetrahydrofuran, N,N'-dimethylacetamide and deionized water.
The method according to claim 6, characterized in that, in the step 1-2, the reducing agent used in the reduction reaction is a medium active reducing agent; the reaction temperature of the reduction reaction is 85-95 °C, and the reaction The time is 0.5-3h; the third solvent used in the reduction reaction includes at least one of tetrahydrofuran, ethyl acetate, chloroform, acetone and methanol;

Wherein, the moderately active reducing agent includes any one of SnCl 2 /concentrated HCl, H 2 -Raney Ni, H 2 -Pd/C, Fe/HCl, and Zn/HCl.
An application of uniform nitrogen-doped graphene interspersed with 15 N and 14 N, characterized in that the application comprises: applying the uniform nitrogen-doped graphene interspersed with 15 N and 14 N according to claim 1 Applied to the preparation of graphene materials or modified graphene materials; or

Applying the uniform nitrogen-doped graphene of 15 N and 14 N interspersed and distributed according to claim 1 to the characterization or detection of physical and chemical properties of graphene materials or modified graphene materials; or

Applying the uniform nitrogen-doped graphene with the interspersed distribution of 15 N and 14 N according to claim 1 to the precise chemical structure characterization of the uniform nitrogen-doped graphene porous material; or

The uniform nitrogen-doped graphene with 15 N and 14 N interspersed and distributed according to claim 1 is applied to the study of intrinsic physical and chemical properties, wherein the study of properties includes: any one of optics, acoustics, electrical conductivity, and thermal conductivity. species; or

Applying the uniform nitrogen-doped graphene with 15 N and 14 N interspersed and distributed as claimed in claim 1 to gas adsorption separation and research on its mechanism; or

The uniform nitrogen-doped graphene with interspersed distribution of 15 N and 14 N described in claim 1 was applied to the study of single-atom catalysis mechanism.