Preparation method and application of triazine-pyrazine-based nitrogen-rich nitrogen-doped porous carbon material

Abstract

The present invention discloses a preparation method and application of a triazine-pyrazine-based nitrogen-rich nitrogen-doped porous carbon material, and relates to the field of porous materials. The present invention uses melamine as a cross-linking center and pyrazine monomers as cross-linking arms to construct a porous organic polymer with a high nitrogen content. The triazine-pyrazine-based nitrogen-rich nitrogen-doped porous carbon material is prepared by washing, purification, drying, activation and carbonization. Due to the presence of highly developed microporous structure and stable nitrogen-rich units, the material has considerable specific surface area, high thermal stability, high chemical stability, high nitrogen content, high CO2 adsorption capacity, high CO2 / N2 selectivity, high carbonization yield, and reusability. It has broad application prospects in the fields of CO2 adsorption and membrane separation.

Description

Technical Field

[0001] The present invention belongs to the field of porous carbon materials, and in particular relates to a preparation method of a triazine-pyrazine-based nitrogen-rich and nitrogen-doped porous carbon material and an application thereof. Background Art

[0002] Currently, large-scale CO2 emissions cause the greenhouse effect, leading to climate change and frequent natural disasters. However, CO2 is also an important carbon resource, and can be used to synthesize organic compounds. Therefore, achieving efficient CO2 capture and separation is one of the most pressing issues facing sustainable development.

[0003] Among various CO2 capture methods, solid adsorption is a CO2 capture method with application potential. The development and selection of high-efficiency solid adsorbents are key, and they need to have superior properties such as large adsorption capacity, high selectivity and reusability at room temperature and pressure. Porous carbon has attracted widespread attention due to its low price, good hydrothermal stability and rich pore structure. The two key factors affecting its capture performance are its microscopic pore structure and nitrogen atom doping. The nitrogen atoms in nitrogen-doped porous carbon produce polar interactions with CO2 molecules, which can increase the adsorption capacity and selectivity of CO2. Based on this, it is necessary to develop porous carbon materials with rich microporous structures and nitrogen atom doping to improve the adsorption capacity, selectivity and repeatability of CO2.

[0004] To date, there are many preparations of nitrogen-doped porous carbon, but the nitrogen content and CO2 adsorption capacity of these nitrogen-doped porous carbon materials are not high enough, the pore size adjustment is not systematic enough, the reaction time is long, and the stability, yield and purity are still low. Usually, the synthesis of nitrogen-doped porous carbon requires a high temperature (150-180°C) and a long preparation cycle (72h), resulting in high preparation costs. Therefore, it is particularly important to systematically study the pore structure, nitrogen content and yield, and purification control methods of porous carbon, and to develop a nitrogen-doped porous carbon material with a simple preparation method, low cost, wide raw material source, high nitrogen content and CO2 capture capacity without affecting the comprehensive performance of the porous carbon material. Summary of the Invention

[0005] In response to the above problems, the present invention uses a new pore structure adjustment method, which mainly improves the yield and purity of the product by adjusting the type of solvent and catalyst; the pore structure, pore size, and nitrogen content of the porous carbon are regulated by adjusting the length, steric hindrance, and type of amine of the cross-linking agent. The longer the cross-linking agent length, the larger the pore size. Compared with primary amines and secondary amines as cross-linking agents, pyrazine is more stable and has a higher yield. The pore size, specific surface area, nitrogen content and performance of nitrogen-doped porous carbon can also be regulated by adjusting the type of activator and the carbonization temperature. The present invention may further guide the synthesis of porous carbon and improve its performance. In order to achieve the above purpose and achieve the above effect, the present invention provides a method for preparing a triazine-pyrazine-based nitrogen-rich nitrogen-doped porous carbon material, comprising the following steps:

[0006] Melamine, pyrazine monomer and solvent are mixed, and a catalyst is added to carry out a cross-linking reaction under a N2 atmosphere. After purification and drying, a porous organic polymer with a high nitrogen content is obtained. After activation and carbonization treatment, a triazine-pyrazine-based nitrogen-rich nitrogen-doped porous carbon material is obtained.

[0007] Preferably, the molar ratio of melamine, pyrazine monomer and catalyst is 1:1.5-2:1.5-2, and the pyrazine monomer is in excess to ensure that the melamine reacts fully.

[0008] Preferably, the pyrazine monomer is a mixture of one or more of 2,6-dichloropyrazine, 5,8-dibromobenzopyrazine, 2-chloromethyl-3-chloropyrazine, 3,5-dichloropyrazine-2-carbonitrile, and 2-bromo-3,5-dichloropyrazine.

[0009] Compared with toxic compounds such as phenol, pyrazine monomer is non-toxic and more environmentally friendly. It also has a symmetrical nitrogen group and a relatively stable structure. During the carbonization process, it is more stable than primary amines and secondary amines and is not easy to gasify. While the high nitrogen retention capacity ensures that the pore structure of the porous carbon is not seriously damaged at high temperatures, the carbonization yield is high.

[0010] Preferably, the solvent is a mixture of one or more of dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), tetrahydrofuran (THF), and anhydrous ethanol.

[0011] Preferably, the catalyst is anhydrous AlCl3, NaOH or sodium carbonate.

[0012] Preferably, the cross-linking reaction time is 6-12 hours and the reaction temperature is 80-120°C.

[0013] Preferably, the specific purification steps are as follows: washing out the unreacted raw materials and DMSO in the product with dichloromethane and anhydrous methanol in sequence, removing the anhydrous methanol in the product with dichloromethane, and then soaking in THF for 2 hours to remove the remaining unreacted melamine.

[0014] Furthermore, the specific steps of the activation and carbonization treatment are as follows:

[0015] A porous organic polymer with a high nitrogen content was mixed with an activator, ground for 0.5-2 hours, and then dried at 80°C in a vacuum oven for 12 hours. Under a nitrogen atmosphere, the temperature was raised to 600-800°C at a rate of 2-5°C / min and maintained for 2 hours. After cooling to room temperature, the product was washed with 5 mol / L HCl and water until the filtrate had a pH of 7 and dried at 80°C for 24 hours to obtain triazine-pyrazine-based nitrogen-rich porous carbon.

[0016] Preferably, the mass ratio of the porous organic polymer with high nitrogen content to the activator is 1:0.5-3.

[0017] Preferably, the activator is a mixture of one or more of NaCl, KCl, Na2CO3, NaOH, KOH, zinc chloride, ferric chloride, potassium carbonate, acetic acid, wood ash, and H3PO4.

[0018] The beneficial effects of the present invention are:

[0019] (1) The present invention selects melamine as the cross-linking center and pyrazine monomer as the cross-linking arm to synthesize a porous organic polymer with a high nitrogen content. The nitrogen atom not only becomes the builder of the main skeleton, but also the content of the introduced N atoms is controllable and the distribution is more uniform. At the same time, the structures of melamine and pyrazine monomers are relatively stable. During the activation and carbonization treatment process, the nitrogen structure is not easy to gasify, and the retention amount of structural N (such as pyridinic nitrogen, pyrrolic nitrogen and graphitic nitrogen) is high, which helps to improve the CO2 adsorption capacity, CO2 / N2 selectivity and carbonization yield.

[0020] (2) The process of the present invention is simple, the reaction conditions are mild, the time is short, the yield is high, and the structural design is strong. The length of the cross-linking agent and the steric hindrance can be adjusted according to the use requirements to control the pore size. The specific surface area, pore structure and nitrogen content of the prepared porous carbon can also be effectively regulated by controlling the type, amount and activation temperature of the activator used in the system.

[0021] (3) The nitrogen-doped porous carbon material prepared by the present invention not only has a considerable specific surface area (up to 2122m 2 / g), high thermal and chemical stability, high nitrogen content, and a microporous structure. It also exhibits high CO2 / N2 selectivity (up to 38.7 at 15% CO2 / N2) and is recyclable. It can be used as an alternative filler to Pebax membranes to improve their gas separation performance. A Pebax mixed matrix membrane containing 3 wt% POP-1-KOH-600 exhibits a CO2 permeability of 491 barrers and a CO2 / N2 selectivity of 62 (0.4 MPa, 25°C). This high-nitrogen-content, nitrogen-doped porous carbon material holds broad application prospects in areas such as CO2 adsorption and membrane separation. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings described herein are used to provide further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments and descriptions of the present invention are used to explain the present invention and do not constitute improper limitations on the present invention.

[0023] Figure 1 is the reaction formula of POP-1, POP-2 and POP-3 prepared in Example 3 and Examples 8-9;

[0024] Figure 2 is a SEM image of POP-1 prepared in Example 3;

[0025] Figure 3 is a SEM image of POP-1-KOH-800 prepared in Example 5;

[0026] Figure 4 is a TEM image of POP-1 prepared in Example 3;

[0027] Figure 5 is a TEM image of POP-1-KOH-800 prepared in Example 5;

[0028] Figure 6 The N2 isotherm adsorption curve and CO2 adsorption curve of the triazine-pyrazine-based nitrogen-rich nitrogen-doped porous carbon prepared in Example 3-9;

[0029] Figure 7 The dynamic penetration curve (a) and cyclic regeneration experiment (b) of the triazine-pyrazine-based nitrogen-rich nitrogen-doped porous carbon prepared in Example 3 are shown. DETAILED DESCRIPTION

[0030] The present invention is further described below with reference to the following examples, comparative examples, and accompanying drawings to enable those skilled in the art to implement the invention with reference to the description. The experimental methods described in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials are commercially available unless otherwise specified.

[0031] Example 1

[0032] Melamine (3.87 g, 30 mmol), 2,6-dichloropyrazine (6.70 g, 45 mmol), and anhydrous DMSO (120 mL) were sequentially added to a 250 mL three-necked flask. NaOH (1.89 g) was added under a nitrogen atmosphere and the mixture was allowed to react at 120°C for 12 hours. After cooling to room temperature, the mixture was washed with dichloromethane and then anhydrous methanol, soaked in tetrahydrofuran for 2 hours, and dried at 80°C for 24 hours to obtain a yellow porous organic polymer, designated POP-1, with a yield of 84%.

[0033] Example 2

[0034] Melamine (3.87 g, 30 mmol), 2,6-dichloropyrazine (6.70 g, 45 mmol), and anhydrous DMF (120 mL) were sequentially added to a 250 mL three-necked flask. AlCl₃ (6.00 g) was added under a nitrogen atmosphere and reacted at 120°C for 6 h. After cooling to room temperature, the mixture was washed with dichloromethane and anhydrous methanol, soaked in tetrahydrofuran for 2 h, and dried at 80°C for 24 h to obtain a yellow porous organic polymer, designated POP-1-2, with a yield of 88%.

[0035] Example 3

[0036] (1) Melamine (3.87 g, 30 mmol), 2,6-dichloropyrazine (6.70 g, 45 mmol), and anhydrous DMSO (120 mL) were added sequentially to a 250 mL three-necked flask. Anhydrous AlCl (6.00 g, 45 mmol) was added under a nitrogen atmosphere and reacted at 120°C for 12 h. The mixture was cooled to room temperature, washed with dichloromethane and anhydrous methanol, soaked in tetrahydrofuran for 2 h, and dried at 80°C for 24 h to obtain a yellow, high-nitrogen-content porous organic polymer, designated POP-1, with a yield of 95%.

[0037] (2) POP-1 and KOH were mixed in a mass ratio of 1:2, ground for 0.5 h, and then dried in vacuum at 80°C for 12 h. Under a nitrogen atmosphere, the temperature was raised to 600°C at a rate of 5°C / min and maintained for 2 h. After cooling to room temperature, the mixture was washed with 5 mol / L HCl and water until the pH of the filtrate reached 7. The mixture was then dried in vacuum at 80°C for 24 h to obtain triazine-pyrazine-rich nitrogen-doped porous carbon, designated POP-1-KOH-600, with a yield of 82%.

[0038] Example 4

[0039] (1) Same as Example 3;

[0040] (2) POP-1 and KOH were mixed in a mass ratio of 1:2, ground for 0.5 h, and then dried in vacuum at 80°C for 12 h. Under a nitrogen atmosphere, the temperature was raised to 700°C at a rate of 5°C / min and maintained for 2 h. After cooling to room temperature, the mixture was washed with 5 mol / L HCl and water until the pH of the filtrate reached 7. The mixture was then dried in vacuum at 80°C for 24 h to obtain triazine-pyrazine-rich nitrogen-doped porous carbon, designated POP-1-KOH-700, with a yield of 70%.

[0041] Example 5

[0042] (1) Same as Example 3;

[0043] (2) POP-1 and KOH were mixed in a mass ratio of 1:2, ground for 0.5 h, and then dried in vacuum at 80°C for 12 h. Under a nitrogen atmosphere, the temperature was raised to 800°C at a rate of 5°C / min and maintained for 2 h. After cooling to room temperature, the mixture was washed with 5 mol / L HCl and deionized water until the pH of the filtrate reached 7. The mixture was then dried in vacuum at 80°C for 24 h to obtain triazine-pyrazine-rich nitrogen-doped porous carbon, designated POP-1-KOH-800, with a yield of 57%.

[0044] Example 6

[0045] (1) Same as Example 3;

[0046] (2) POP-1 and ZnCl2 were mixed in a mass ratio of 1:2, ground for 0.5 h, and then dried in vacuum at 80°C for 12 h. Under a nitrogen atmosphere, the temperature was raised to 700°C at a rate of 5°C / min and maintained for 2 h. After cooling to room temperature, the mixture was washed with 5 mol / L HCl and deionized water until the pH of the filtrate reached 7. The mixture was then dried in vacuum at 80°C for 24 h to obtain triazine-pyrazine-rich nitrogen-doped porous carbon, designated POP-1-ZnCl2-700, with a yield of 71%.

[0047] Example 7

[0048] (1) Same as Example 3;

[0049] (2) POP-1 and FeCl3 were mixed in a mass ratio of 1:2, ground for 0.5 h, and then dried in vacuum at 80°C for 12 h. Under a nitrogen atmosphere, the temperature was raised to 700°C at a rate of 5°C / min and maintained for 2 h. After cooling to room temperature, the mixture was washed with 5 mol / L HCl and deionized water until the pH of the filtrate reached 7. The mixture was then dried in vacuum at 80°C for 24 h to obtain triazine-pyrazine-rich nitrogen-doped porous carbon, designated POP-1-FeCl3-700, with a yield of 73%.

[0050] Example 8

[0051] (1) Melamine (3.87 g, 30 mmol), 2-chloromethyl-3-chloropyrazine (7.33 g, 45 mmol), and anhydrous DMSO (120 mL) were sequentially added to a 250 mL three-necked flask. Anhydrous AlCl (6.54 g, 45 mmol) was added under a nitrogen atmosphere and reacted at 120°C for 12 h. The mixture was cooled to room temperature, washed with methanol, dichloromethane, and tetrahydrofuran, and dried at 80°C for 24 h to obtain a porous organic polymer with a high nitrogen content, designated as POP-2, with a yield of 87%.

[0052] (2) POP-2 and KOH were mixed in a mass ratio of 1:2, ground for 0.5 h, and then dried in vacuum at 80°C for 12 h. Under a nitrogen atmosphere, the temperature was raised to 700°C at a rate of 5°C / min and maintained for 2 h. After cooling to room temperature, the mixture was washed with 5 mol / L HCl and water until the pH of the filtrate reached 7. The mixture was then dried in vacuum at 80°C for 24 h to obtain triazine-pyrazine-rich nitrogen-doped porous carbon, designated POP-2-KOH-700, with a yield of 68%.

[0053] Example 9

[0054] (1) Melamine (3.87 g, 30 mmol), 5,8-dibromobenzopyrazine (12.95 g, 45 mmol), and anhydrous DMSO (120 mL) were sequentially added to a 250 mL three-necked flask. Anhydrous AlCl (11.59 g, 45 mmol) was added under a nitrogen atmosphere and reacted at 120°C for 12 h. The mixture was cooled to room temperature, washed with methanol, dichloromethane, and tetrahydrofuran, and dried at 80°C for 24 h to obtain a porous organic polymer with a high nitrogen content, designated as POP-3, with a yield of 92%.

[0055] (2) POP-3 and KOH were mixed in a mass ratio of 1:2, ground for 0.5 h, and then dried in vacuum at 80°C for 12 h. Under a nitrogen atmosphere, the temperature was raised to 700°C at a rate of 5°C / min and maintained for 2 h. After cooling to room temperature, the mixture was washed with 5 mol / L HCl and deionized water until the pH of the filtrate reached 7. The mixture was then dried in vacuum at 80°C for 24 h to obtain triazine-pyrazine-rich nitrogen-doped porous carbon, designated POP-3-KOH-700, with a yield of 67%.

[0056] Example 10

[0057] (1) Under N2 atmosphere, melamine (0.30 g, 2.40 mmol), formamide (0.16 g, 3.60 mmol), and anhydrous DMSO (15 mL) were added sequentially to a 25 mL three-necked flask equipped with a stirring paddle and a condenser and reacted at 180°C for 72 h. Afterwards, the mixture was washed with methanol, dichloromethane, N,N-dimethylformamide, and tetrahydrofuran to obtain a white solid. The solid was then extracted with THF for 24 h, filtered, and dried in vacuo at 120°C for 12 h to obtain a porous organic polymer, designated POP-4, with a yield of 82%.

[0058] (2) 0.5 g of POP-4 and 1.0 g of ZnCl2 were thoroughly mixed and ground in a mortar, and the mixture was placed on a ceramic ark. Under a N2 atmosphere, the temperature was raised to 700°C at a rate of 5°C / min and kept constant for 2 h. After cooling to room temperature, the filtrate was washed with a 3 mol / L hydrochloric acid aqueous solution and deionized water until the pH of the filtrate was 7. The filtrate was dried under vacuum at 120°C for 24 h to obtain nitrogen-doped porous carbon, designated as POP-4-ZnCl2-700, with a yield of 63%. It is worth noting that when KOH is used as an activator, the product will produce salt, which is soluble in water and has an extremely low yield (12%).

[0059] Table 1: Carbonization process, BET data and nitrogen content corresponding to Examples 3-10

[0060]

[0061] a Total pore volume at relative pressure P / P0 = 0.99.

[0062] b Cumulative micropore volume with pore diameter less than 0.8 nm using the NLDFT model, in cm 3 / g.

[0063] c Specific surface area was calculated using the BET method.

[0064] d Pore diameter calculated using the BJH method.

[0065] eTest conditions are 25°C, 780 mm Hg.

[0066] The pore structure parameters and specific surface area of ​​each embodiment were obtained by N2 adsorption-desorption characterization test, as shown in Table 1 and Figure 6 As shown. The microporous structure plays a major role in the CO2 adsorption process. A higher pore volume helps improve the CO2 adsorption performance of porous carbon. The potential energy of gas-solid interaction between adjacent walls in the micropores overlaps with each other, which significantly enhances the CO2 adsorption capacity of the micropores. The specific surface area of ​​the nitrogen-doped porous carbon material of the present invention is as high as 2122m 2 / g, with a nitrogen content of up to 12.9%, effectively improving the CO2 adsorption performance. At 25°C and 780mmHg, the CO2 adsorption capacity is between 2.86-3.49mmol / g, and the CO2 / N2 selectivity reaches 37.8.

[0067] Depend on Figure 2 and Figure 3 It is known that the pore size and porosity of POP-1 before carbonization are small. After activation and carbonization, the porosity increases, the specific surface area increases, and the CO2 adsorption capacity increases. TEM results ( Figure 4 and Figure 5)It further shows that the porosity of POP-1 increases after activation and carbonization, presenting micropore characteristics. It can be seen from Table 1 that the specific surface area, total pore volume and micropore volume all decrease with the increase of temperature. POP-1-KOH-700 has the largest values, indicating that as the activation temperature increases, the activator etches the pore walls, widening the original pore structure and generating new pore structures. When the activation temperature is 800 °C, the specific surface area, total pore volume and micropore volume decrease. An excessively high activation temperature will cause some pores to volatilize. The average pore diameter of POP-1-KOH-800 is smaller, and the generated ultra-micropores are not volatilized and are well retained. The higher the carbonization temperature, the lower the yield, because the polymer is more fully carbonized at high temperatures, and its properties are mainly related to the specific surface area, pore structure, porosity and nitrogen content.

[0068] Examples 4 and 6-7 mainly studied the effects of activator types on the pore structure and properties of porous carbon. From Table 1 and Figure 6 it is known that the isotherm of POP-1 is classified as type I, indicating its microporous structure. At a relatively low relative pressure (P / P0 < 0.01), the N2 capacity increases rapidly, indicating that it is mainly a microporous structure. At medium relative pressure and under KOH activation, S BET and V total increase with the increase of carbonization temperature. At 700 °C, the S BET and V total of POP-1-KOH-700 are the highest (2050 m 2 / g and 1.13 cm 3 / g respectively). Higher temperatures may cause chemical etching on the carbon framework and generate additional large pore volumes. At the same time, different activators will produce different S BET and V total . The S BET and V total of POP-1-FeCl3-700 with FeCl3 as the activator are the lowest (976 m 2 / g and 0.82 cm 3 / g respectively), while the nitrogen content of POP-1-ZnCl2-700 with ZnCl2 as the activator is the highest (12.5%). Therefore, the activator improves the structural properties of POP-1 in the order of FeCl3 < ZnCl2 < KOH. At 25 °C, the CO2 adsorption capacity is 3.01 - 3.49 mmol / g, indicating that the porous structure and nitrogen content can be easily adjusted by controlling the carbonization temperature and activator. This adsorption capacity is at a relatively high level among porous carbon materials, and it is a carbon material with a relatively high specific surface area and nitrogen content.

[0069] Examples 4 and 8-10 primarily investigated the effects of crosslinker length, steric hindrance, and amine type on the pore structure, pore size, and performance of the porous carbon. Table 1 shows that the pore structure, pore size, and nitrogen content of the porous carbon can be manipulated by adjusting the crosslinker length, steric hindrance, and amine type. Longer crosslinker lengths increase pore size. Compared to primary and secondary amines, pyrazine is more stable and offers higher yields as a crosslinker.

[0070] In addition, the porous carbon prepared by the present invention can be used as an alternative filler for Pebax membrane to improve the gas separation performance of the membrane. The present invention mixes 0.002g POP-1-KOH-600 and 6.26g n-butanol by ultrasonication for 2h to obtain a uniform suspension, then adds 0.398g Pebax-2533 and vigorously stirs at 80°C until Pebax is completely dissolved. The suspension is then coated on a glass plate to form a membrane, and then placed at room temperature for 12h to allow the solvent to evaporate, dried at 80°C for 24h, and peeled off from the glass plate to form a mixed matrix membrane with a thickness of about 50μm. Its CO2 permeability reaches 491Barrer and CO2 / N2 selectivity reaches 62 (0.4MPa, 25°C), which is close to the 2019 Robeson upper limit.

[0071] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the description and implementation methods. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A method for preparing triazine-pyrazine-based nitrogen-rich nitrogen-doped porous carbon material, characterized by: The steps include: Melamine, pyrazine monomer and solvent are mixed, and a catalyst is added to carry out a cross-linking reaction under a nitrogen atmosphere. After purification and drying, a porous organic polymer with a high nitrogen content is obtained. After activation and carbonization treatment, a triazine-pyrazine-based nitrogen-rich nitrogen-doped porous carbon material is obtained. The molar ratio of melamine, pyrazine monomer and catalyst is 1:1.5-2:1.5-2; The reaction temperature of the cross-linking reaction is 80-120 o C, reaction time is 6-12 h; The specific purification steps are as follows: washing with dichloromethane and anhydrous methanol in sequence, and then soaking in tetrahydrofuran for 2 hours; The specific steps of the activation and carbonization treatment are as follows: The porous organic polymer with high nitrogen content was mixed with the activator in a mass ratio of 1:0.5-3, and after grinding for 0.5-2 h, 80 o C vacuum drying for 12 h, and then drying at 2-5 o C / min increased to 600-800 o C for 2 h, cooled to room temperature, washed with 5 mol / L HCl and water until the pH of the filtrate reached 7, and dried to obtain triazine-pyrazine-based nitrogen-rich nitrogen-doped porous carbon.

2. The method for preparing triazine-pyrazine-based nitrogen-rich and nitrogen-doped porous carbon materials according to claim 1, characterized in that: The pyrazine monomer is a mixture of one or more of 2,6-dichloropyrazine, 5,8-dibromobenzopyrazine, 2-chloromethyl-3-chloropyrazine, 3,5-dichloropyrazine-2-carbonitrile, and 2-bromo-3,5-dichloropyrazine.

3. The method for preparing triazine-pyrazine-based nitrogen-rich and nitrogen-doped porous carbon materials according to claim 1, characterized in that: The solvent is a mixture of one or more of dimethyl sulfoxide, N,N-dimethylformamide, tetrahydrofuran, and anhydrous ethanol.

4. The method for preparing triazine-pyrazine-based nitrogen-rich and nitrogen-doped porous carbon materials according to claim 1, characterized in that: The catalyst is anhydrous AlCl3, NaOH or sodium carbonate.

5. The method for preparing triazine-pyrazine-based nitrogen-rich and nitrogen-doped porous carbon materials according to claim 1, characterized in that: The activator is a mixture of one or more of NaCl, KCl, Na2CO3, NaOH, KOH, zinc chloride, ferric chloride, potassium carbonate, acetic acid, wood ash, and H3PO4.

6. A triazine-pyrazine-based nitrogen-rich nitrogen-doped porous carbon material prepared according to any one of claims 1 to 5, wherein the nitrogen-doped porous carbon material is used in the fields of CO2 adsorption and gas separation membranes.

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