Coal tar-based nitrogen-sulfur co-doped porous carbon material and preparation method thereof

Abstract

The invention belongs to the technical field of carbon materials, and relates to a coal tar-based nitrogen-sulfur co-doped porous carbon material and a preparation method thereof.The coal tar-based nitrogen-sulfur co-doped porous carbon material is prepared from waste coal tar as a carbon source, animal hair as a carbon source, a nitrogen source and a sulfur source, shrimp and crab shells as a nitrogen source and a template agent and strong base as an activating agent through hydrothermal carbonization and high-temperature activation. The carbon material with high specific surface area and adjustable pore structure is obtained, and contains a certain amount of heteroatom nitrogen and sulfur. The shrimp and crab shell particles are used as a template agent to provide internal initial pores; in the hydrothermal pre-carbonization process, a high-temperature alkali solution can quickly dissolve hair to form polypeptide substances, so that the polypeptide substances in a pyrolysis product are uniformly mixed with tar, alkali, crustacean particles and the like, and uniform co-doping of nitrogen and sulfur is facilitated. The problems of low carbon production rate, serious graphitization, low porosity, difficulty in directional regulation and control of a pore structure and low content of heteroatoms in tar in the prior art are solved, and the specific surface area of the porous carbon material is increased.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon materials, and relates to a coal-tar-based nitrogen and sulfur co-doped porous carbon material and a preparation method thereof. Background Art

[0002] In the context of energy transformation and sustainable development, porous carbon materials have attracted much attention due to their unique properties in the fields of energy storage, adsorption separation, catalysis, etc. As an important carbon source, coal tar has rich resources, low cost and diverse chemical structures, making it an ideal raw material for preparing porous carbon materials. However, there are still a series of technical challenges in the current methods for preparing carbon materials from coal tar, such as high graphitization degree, insufficient activation degree, and difficult pore structure regulation, which restrict its wide application in various fields. Therefore, seeking an efficient and controllable activation method to improve the performance of coal-tar-based porous carbon materials has become an urgent need in current research.

[0003] As a by-product of coal chemical industry, the post-treatment process of coal tar is complex and causes relatively large environmental pollution; the high-value utilization of coal tar can be realized by using it to prepare carbon materials. However, the direct pyrolysis carbon of coal tar has a high graphitization degree, and magnesia and other substances are often used as sacrificial template agents to catalyze carbonization and generate pores, with high costs and low specific surface areas. For example, the existing patent CN201710020477.X proposes a coal-tar-based porous carbon obtained by first adding an ionic liquid to coal tar to completely dissolve the coal tar in the ionic liquid and then sequentially adding a ground and pulverized activator, with a specific surface area of 1900 m 2 / g. In a 6M KOH electrolyte, its specific capacitance reaches 314 F / g. Patent CN201710899204.7 provides a preparation method for biomass-tar-derived carbon quantum dots, including the following steps: (1) placing molecular sieves and biomass tar with a mass ratio greater than or equal to 2 in a reaction vessel and heating to 300°C - 800°C for catalytic reaction; (2) cooling the molecular sieves after the catalytic reaction, and then mixing the cooled molecular sieves with a polar solvent for ultrasonic treatment; (3) filtering, evaporating and drying the mixture after ultrasonic treatment to obtain carbon quantum dots; Patent CN201811102408.4 discloses a preparation method for a biomass-tar-based high-specific-surface-area porous carbon for physical adsorption of carbon dioxide. Using biomass tar as a carbon source, porous calcium oxide formed after calcining eggshells as a template, and potassium hydroxide as an activator, a porous carbon with a high specific surface area, a relatively high pore volume, especially a high proportion of micropores is prepared. This porous carbon, as a CO2 solid adsorbent, has high physical absorption and stability, providing a new method for solving the problem of difficult resource utilization of existing biomass tar.

[0004] In summary, there are some problems in the existing methods for preparing carbon materials from coal tar. For example, due to the strong fluidity and high hydrogen content of tar, graphitization is likely to occur; tar is easily evaporated into gaseous volatile components at high temperatures, resulting in a low carbon yield; there is a lack of pore-forming driving force during the carbonization process of tar, leading to insufficient porosity. Using templating agents such as MgO for pore formation has a high cost and a low specific surface area. Summary of the Invention

[0005] In view of the problems existing in the prior art, the present invention provides a method for preparing a coal-tar-based nitrogen and sulfur co-doped porous carbon material, which solves the problems of low carbon yield, serious graphitization, low porosity, difficulty in directional regulation of pore structure, and low heteroatom content in tar in the prior art, and improves the specific surface area of the porous carbon material.

[0006] The present invention is realized through the following technical solutions: A method for preparing a coal-tar-based nitrogen and sulfur co-doped porous carbon material, comprising: Using coal tar as the carbon source, animal hair as the carbon source, nitrogen source, and sulfur source, crustacean substances as the nitrogen source and templating agent, and strong base as the activator. After hydrothermal carbonization and high-temperature activation treatment, a coal-tar-based nitrogen and sulfur co-doped porous carbon material is obtained. Preferably, the mass ratio between the crustacean substance, animal hair, coal tar, and strong base is 1.5 - 2.5:0.5 - 1.5:1.5 - 2.5:4 - 7.

[0007] Preferably, the specific process of the hydrothermal carbonization and high-temperature activation treatment is as follows: Mix the crustacean substance, animal hair, coal tar, and strong base in a reaction vessel for hydrothermal reaction. Heat it to 150 - 300 °C in a closed environment, keep it for 1 - 5 h, and then cool it to room temperature. Stir and evaporate the obtained slurry to a solid state at 50 - 70 °C; Heat the evaporated solid to 700 - 900 °C in an inert atmosphere and keep it for 1 - 4 h, then cool it to room temperature and wash it successively with hydrochloric acid solution and deionized water. After drying, a coal-tar-based nitrogen and sulfur co-doped porous carbon material is obtained.

[0008] Preferably, the inert gas is nitrogen or argon.

[0009] Preferably, the concentration of the hydrochloric acid solution is 1 - 3 mol / L.

[0010] Preferably, the strong base uses at least one of KOH, LiOH, and NaOH.

[0011] Preferably, when using the crustacean substance, it needs to be dried, ground, and sieved to obtain crustacean particles smaller than 400 mesh.

[0012] Preferably, the crustacean material is the shell of shrimp and crab crustaceans.

[0013] Preferably, the total specific surface area of the coal-tar-based nitrogen and sulfur co-doped porous carbon material reaches 2983 m 2 / g, the micropore specific surface area reaches 2123 m 2 / g, and the mesopore specific surface area reaches 860 m 2 / g.

[0014] A coal-tar-based nitrogen and sulfur co-doped porous carbon material is prepared based on the preparation method of the coal-tar-based nitrogen and sulfur co-doped porous carbon material described above.

[0015] Compared with the prior art, the present invention has the following beneficial technical effects: The present invention provides a coal-tar-based nitrogen and sulfur co-doped porous carbon material and a preparation method thereof. Using waste coal tar as a carbon source, animal hair as a carbon source, nitrogen source and sulfur source, shrimp and crab crustaceans as a nitrogen source and template agent, and strong alkali as an activator, through hydrothermal carbonization and high-temperature activation, a carbon material with a high specific surface area and adjustable pore structure is obtained, and contains a certain amount of heteroatoms nitrogen and sulfur. The shrimp and crab crustacean particles as a template agent provide the initial pores inside, and the size of the initial pores inside the carbon material can be adjusted by controlling its particle size, and the content of the pores can be adjusted by controlling its dosage; during the hydrothermal pre-carbonization process, the high-temperature alkali solution can quickly dissolve the hair to form polypeptide substances, realizing the uniform mixing of polypeptide substances, tar, alkali, crustacean particles, etc. in the pyrolysis products, which is helpful for the uniform co-doping of nitrogen and sulfur. During the high-temperature activation process, the uniformly distributed KOH inside can further activate and etch the carbon structure and generate a large number of micropores; and a part of the calcium carbonate in the crustacean particles decomposes to produce CO2, which is beneficial to the formation of accessible pores, realizing the high-value utilization of solid waste. Aiming at the problem of low carbon production rate, the present invention promotes the condensation of tar through hydrothermal pre-carbonization in a sealed environment, improving the carbon production rate; at the same time, the calcium substance in the shrimp and crab crustaceans can also catalyze the condensation of tar, synergistically improving the carbon production rate. Aiming at the problems of serious graphitization, low porosity, and difficulty in directional regulation of pore structure, the pores of the initial carbon material are adjusted by controlling the particle size and dosage of the shrimp and crab crustacean particle template agent; coupling with the activation of uniformly distributed strong alkali, the porosity of the carbon material is further improved. Aiming at the problems of low heteroatom content in tar, etc., through the dissolution and mixing of hair in high-temperature alkali solution (hydrothermal environment), the uniform co-doping of nitrogen and sulfur is realized. Finally, a nitrogen and sulfur co-doped porous carbon with a high specific surface area is obtained, which has excellent electrochemical properties. Description of the Drawings

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can be obtained based on these drawings.

[0017] Figure 1 SEM image of the target porous carbon material sample of Example 1; Figure 2 EDS spectra of Example 1, where (a), (b), (c), and (d) are the EDS spectra of the C, N, O, and S elements of the target porous carbon material sample, respectively; Figure 3 Nitrogen adsorption - desorption isotherm of the target porous carbon material sample of Example 1. Detailed implementation manners

[0018] The following further elaborates on the present invention in detail with specific embodiments, which is an explanation rather than a limitation of the present invention.

[0019] To enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0020] The present invention aims to improve the pore structure, specific surface area, and electrochemical performance of coal - tar - based porous carbon materials. By introducing alkaline activators and templating agents, it is expected to achieve a higher degree of pore structure regulation during the activation process and increase the specific surface area of the material; by introducing animal hair, in - situ co - doping of nitrogen and sulfur can be achieved, thereby further optimizing its electrochemical performance. This invention provides a new solution for the efficient preparation of coal - tar - based porous carbon materials.

[0021] Example 1 (1) Take the shells of shrimps and crabs, dry them in a forced - air drying oven at 120 °C for 4 h, then grind them using a planetary ball mill and pass through a 400 - mesh standard sieve to obtain shell particles with a particle size less than 400 mesh. Collect human hair, cut it into pieces about 2 cm in length, wash it with deionized water, and dry it for later use.

[0022] (2) Stir and mix the shell particles, cut animal hair, coal tar, and KOH evenly in a mass ratio of 2:1:2:5, and finally add deionized water to completely submerge the mixture.

[0023] (2) Heat the above mixture in a hydrothermal reactor under high pressure and seal it. Heat it up to 200 °C at a rate of 5 °C / min, keep it for 2 h, and then cool it to room temperature. Stir and evaporate the obtained slurry at 60 °C until it becomes a solid state.

[0024] (3) Place the evaporated solid in a muffle furnace, heat it to 800 °C under a nitrogen atmosphere and keep it for 2 h, and then cool it to room temperature to obtain the activated product; Immerse the activated product in a 2 mol / L hydrochloric acid solution, perform ultrasonic treatment (power 200 W) for 20 min, and then filter it. Repeat this process 3 times until the pH is neutral.

[0025] Wash it ultrasonically with deionized water 3 times, filter it, and place it in a vacuum drying oven to dry at 60 °C for 12 h to obtain the final product, the target porous carbon material.

[0026] Detection, analysis and characterization: Figure 1 It is the SEM image of the target porous carbon material sample in Example 1. It can be seen from this figure that the sample shows the characteristics of hierarchical pores; Figure 2 For Example 1, (a), (b), (c), and (d) are the EDS spectra of C, N, O, and S elements of the target porous carbon material sample respectively; it can be seen from this figure that N and S are evenly distributed on the surface of the carbon material. The EDS statistical results show that the N doping amount reaches 5.2 at%, and the S doping amount reaches 1.3 at%. Figure 3 It is the nitrogen adsorption - desorption isotherm of the target porous carbon material sample in Example 1. It can be seen from the figure that the sample has a rich microporous and mesoporous structure. The analysis results show that its total specific surface area reaches 2983 m 2 / g, the microporous specific surface area reaches 2123 m 2 / g, and the mesoporous specific surface area reaches 860 m 2 / g.

[0027] The shrimp and crab shell particles act as a template agent to provide the initial pores inside. The size of the initial pores inside the carbon material can be adjusted by controlling their particle size, and the pore content can be adjusted by controlling their dosage. During the hydrothermal pre - carbonization process, the high - temperature alkaline solution can quickly dissolve the hair to form polypeptide substances, realizing the uniform mixing of polypeptide substances with tar, alkali, shell particles, etc. in the pyrolysis products, which is helpful for the uniform co - doping of nitrogen and sulfur. During the high - temperature activation process, the uniformly distributed KOH inside can further activate and etch the carbon structure and generate a large number of micropores; and part of the calcium carbonate in the shell particles decomposes to produce CO2, which is beneficial to the formation of accessible pores, realizing the high - value utilization of solid waste.

[0028] Example 2 (1) Take the shrimp and crab shell, dry it in a forced-air drying oven at 120 °C for 4 h, then grind it using a planetary ball mill and pass through a 400-mesh standard sieve to obtain shell particles with a particle size less than 400 mesh. Collect human hair, cut it into pieces about 2 cm in length, wash it with deionized water and then dry it for later use.

[0029] (2) Stir and mix the shell particles, cut animal hair, coal tar, and LiOH evenly in a mass ratio of 2:1:2:5, and finally add deionized water until the mixture is completely submerged.

[0030] (2) Heat the above mixture in a hydrothermal reaction kettle under high pressure and seal it, heat it up to 200 °C at a rate of 5 °C / min, hold for 2 h and then cool to room temperature. Stir and evaporate the obtained slurry to a solid state at 60 °C.

[0031] (3) Place the evaporated solid in a muffle furnace, heat it to 800 °C in a nitrogen atmosphere and hold for 2 h, then cool to room temperature to obtain the activated product; Immerse the activated product in a 2 mol / L hydrochloric acid solution, perform ultrasonic treatment (power 200 W) for 20 min and then filter, repeat 3 times until the pH is neutral.

[0032] Ultrasonically clean it 3 times with deionized water, filter and then place it in a vacuum drying oven to dry at 60 °C for 12 h to obtain the final product, the target porous carbon material.

[0033] Example 3 (1) Take the shrimp and crab shell, dry it in a forced-air drying oven at 120 °C for 4 h, then grind it using a planetary ball mill and pass through a 400-mesh standard sieve to obtain shell particles with a particle size less than 400 mesh. Collect human hair, cut it into pieces about 2 cm in length, wash it with deionized water and then dry it for later use.

[0034] (2) Stir and mix the shell particles, cut animal hair, coal tar, and NaOH evenly in a mass ratio of 2:1:2:5, and finally add deionized water until the mixture is completely submerged.

[0035] (2) Heat the above mixture in a hydrothermal reaction kettle under high pressure and seal it, heat it up to 200 °C at a rate of 5 °C / min, hold for 2 h and then cool to room temperature. Stir and evaporate the obtained slurry to a solid state at 60 °C.

[0036] (3) Place the evaporated solid in a muffle furnace, heat it to 800 °C in a nitrogen atmosphere and hold for 2 h, then cool to room temperature to obtain the activated product; Immerse the activated product in a 2 mol / L hydrochloric acid solution, perform ultrasonic treatment (power 200 W) for 20 min and then filter, repeat 3 times until the pH is neutral.

[0037] The product was ultrasonically cleaned three times with deionized water, filtered by suction, and then dried in a vacuum drying oven at 60 °C for 12 h to obtain the final target porous carbon material.

[0038] Example 4 (1)Take the shrimp and crab shell, dry it in a forced air drying oven at 120 °C for 4 h, then grind it using a planetary ball mill and pass through a 400-mesh standard sieve to obtain shell particles with a particle size less than 400 mesh. Collect human hair, cut it into pieces about 2 cm in length, wash it with deionized water, and dry it for later use.

[0039] (2)Stir and mix the shell particles, cut animal hair, coal tar, and KOH evenly in a mass ratio of 1.5:0.5:1.5:4, and finally add deionized water until the mixture is completely submerged.

[0040] (2)Heat the above mixture in a hydrothermal reaction kettle under high pressure and seal, heat it to 300 °C at a rate of 5 °C / min, keep it for 3 h, and then cool it to room temperature. Stir and evaporate the obtained slurry to a solid state at 60 °C.

[0041] (3)Place the evaporated solid in a muffle furnace, heat it to 900 °C in a nitrogen atmosphere and keep it for 1 h, then cool it to room temperature to obtain the activated product; Immerse the activated product in a 3 mol / L hydrochloric acid solution, ultrasonically treat it (power 200 W) for 20 min, then filter by suction, and repeat 3 times until the pH is neutral.

[0042] Example 5 (1)Take the shrimp and crab shell, dry it in a forced air drying oven at 120 °C for 4 h, then grind it using a planetary ball mill and pass through a 400-mesh standard sieve to obtain shell particles with a particle size less than 400 mesh. Collect human hair, cut it into pieces about 2 cm in length, wash it with deionized water, and dry it for later use.

[0043] (2)Stir and mix the shell particles, cut animal hair, coal tar, and KOH evenly in a mass ratio of 2.5:1.5:2.5:7, and finally add deionized water until the mixture is completely submerged.

[0044] (2)Heat the above mixture in a hydrothermal reaction kettle under high pressure and seal, heat it to 150 °C at a rate of 3 °C / min, keep it for 5 h, and then cool it to room temperature. Stir and evaporate the obtained slurry to a solid state at 60 °C.

[0045] (3)Place the evaporated solid in a muffle furnace, heat it to 700 °C in a nitrogen atmosphere and keep it for 3 h, then cool it to room temperature to obtain the activated product; Immerse the activated product in a 1 mol / L hydrochloric acid solution, ultrasonically treat it (power 200 W) for 20 min, then filter by suction, and repeat 3 times until the pH is neutral.

[0046] Example 6 (1) Take the shrimp and crab carapace shells, dry them in a forced-air drying oven at 120 °C for 4 h, then grind them using a planetary ball mill and pass through a 400-mesh standard sieve to obtain carapace particles with a particle size smaller than 400 mesh. Collect human hair, cut it into pieces about 2 cm in length, wash it with deionized water, and then dry it for later use.

[0047] (2) Stir and mix the carapace particles, cut animal hair, coal tar, and KOH evenly according to the mass ratio of 2:0.5:1.5:6, and finally add deionized water until the mixture is completely submerged.

[0048] (2) Heat the above mixture in a hydrothermal reaction kettle under high pressure and seal, heat it to 250 °C at a rate of 3 °C / min, keep it for 5 h, and then cool it to room temperature. Stir and evaporate the obtained slurry to a solid state at 60 °C.

[0049] (3) Place the evaporated solid in a muffle furnace, heat it to 850 °C in a nitrogen atmosphere and keep it for 3 h, and then cool it to room temperature to obtain the activated product; Immerse the activated product in a 1 mol / L hydrochloric acid solution, perform ultrasonic treatment (power 200 W) for 20 min, then filter by suction, and repeat 3 times until the pH is neutral.

[0050] Example 7 (1) Take the shrimp and crab carapace shells, dry them in a forced-air drying oven at 120 °C for 4 h, then grind them using a planetary ball mill and pass through a 400-mesh standard sieve to obtain carapace particles with a particle size smaller than 400 mesh. Collect human hair, cut it into pieces about 2 cm in length, wash it with deionized water, and then dry it for later use.

[0051] (2) Stir and mix the carapace particles, cut animal hair, coal tar, and NaOH evenly according to the mass ratio of 2:1:1.5:5, and finally add deionized water until the mixture is completely submerged.

[0052] (2) Heat the above mixture in a hydrothermal reaction kettle under high pressure and seal, heat it to 250 °C at a rate of 3 °C / min, keep it for 5 h, and then cool it to room temperature. Stir and evaporate the obtained slurry to a solid state at 70 °C.

[0053] (3) Place the evaporated solid in a muffle furnace, heat it to 850 °C in a nitrogen atmosphere and keep it for 3 h, and then cool it to room temperature to obtain the activated product; Immerse the activated product in a 1.5 mol / L hydrochloric acid solution, perform ultrasonic treatment (power 200 W) for 20 min, then filter by suction, and repeat 3 times until the pH is neutral.

[0054] Further, to address the problem of low carbon production rate, the present invention promotes the condensation of tar through hydrothermal pre-carbonization in a sealed environment, thereby increasing the carbon production rate; at the same time, the calcium substances in the shrimp and crab carapace can also catalyze the condensation of tar, synergistically increasing the carbon production rate.

[0055] Furthermore, aiming at the problems of severe graphitization, low porosity, and difficult directional regulation of pore structure, the pores of the initial carbon material are adjusted by regulating the particle size and dosage of the shrimp and crab shell particle template agent; coupling with the activation of uniformly distributed strong base further increases the porosity of the carbon material.

[0056] Furthermore, aiming at problems such as low heteroatom content in tar, the uniform co-doping of nitrogen and sulfur is achieved through the dissolution and blending of hair in high-temperature alkaline solution (hydrothermal environment). Finally, highly specific surface area porous carbon co-doped with nitrogen and sulfur is obtained, which has excellent electrochemical performance.

[0057] It should be noted that the terms "comprising" and "having" in the description, claims and above-mentioned drawings of the present invention, and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0058] In the present invention, if there is no special indication, all the embodiments and preferred implementation methods mentioned herein can be combined with each other to form new technical solutions.

[0059] In the present invention, if there is no special indication, all the technical features and preferred features mentioned herein can be combined with each other to form new technical solutions.

[0060] In the present invention, if there is no special indication, the percentage (%) or part refers to the weight percentage or weight part relative to the composition.

[0061] In the present invention, if there is no special indication, the various components or their preferred components involved can be combined with each other to form new technical solutions.

[0062] In the present invention, unless otherwise stated, the numerical range "a~b" represents the abbreviated representation of any real number combination between a and b, where a and b are both real numbers. For example, the numerical range "6~22" means that all real numbers between "6~22" have been fully listed herein, and "6~22" is only the abbreviated representation of these numerical combinations.

[0063] The "range" disclosed in the present invention can be in the form of one or more lower limits and one or more upper limits respectively.

[0064] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terms used in the description of the present invention herein are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0065] As described above, it is only the preferred embodiment of the present invention and does not impose any formal limitation on the present invention. Any ordinary technician in this industry can smoothly implement the present invention as shown in the accompanying drawings of the specification and as described above. However, any equivalent changes such as slight modifications, decorations, and evolutions made by those skilled in the art within the scope of the technical solution of the present invention by using the technical content disclosed above are equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications, and evolutions made to the above embodiments based on the essence of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A preparation method of a coal-tar-based nitrogen and sulfur co-doped porous carbon material, characterized in that, including, using coal tar as the carbon source, animal hair as the carbon source, nitrogen source and sulfur source, crustacean substances as the nitrogen source and template agent, and strong alkali as the activator, a nitrogen and sulfur co-doped porous carbon material based on coal tar is obtained after hydrothermal carbonization and high-temperature activation treatment.

2. The preparation method of a coal-tar-based nitrogen and sulfur co-doped porous carbon material according to claim 1, characterized in that, The mass ratio between the crustacean substances, animal hair, coal tar and strong alkali is 1.5 - 2.5: 0.5 - 1.5: 1.5 - 2.5: 4 - 7.

3. The preparation method of a coal-tar-based nitrogen-sulfur co-doped porous carbon material according to claim 1, characterized in that, The specific processes of the hydrothermal carbonization and high-temperature activation treatment are as follows: Mix the crustacean substances, animal hair, coal tar and strong alkali in the reactants in a hydrothermal reaction kettle, heat it to 150 - 300 °C in a closed environment, keep it for 1 - 5 h and then cool it to room temperature. The obtained slurry is stirred and evaporated to dryness at 50 - 70 °C until it becomes a solid state; Heat the dried solid to 700 - 900 °C in an inert atmosphere and keep it for 1 - 4 h, then cool it to room temperature and wash it successively with hydrochloric acid solution and deionized water. After drying, a nitrogen and sulfur co-doped porous carbon material based on coal tar is obtained.

4. The preparation method of a coal-tar-based nitrogen and sulfur co-doped porous carbon material according to claim 3, characterized in that, The inert gas is nitrogen or argon.

5. The preparation method of a coal-tar-based nitrogen and sulfur co-doped porous carbon material according to claim 3, characterized in that The concentration of the hydrochloric acid solution is 1 - 3 mol / L.

6. The preparation method of a coal-tar-based nitrogen and sulfur co-doped porous carbon material according to claim 1, characterized in that, The strong alkali uses at least one of KOH, LiOH and NaOH.

7. The preparation method of a coal-tar-based nitrogen-sulfur co-doped porous carbon material according to claim 1, characterized in that, When using the crustacean substances, they need to be dried, ground and sieved to obtain crust particles smaller than 400 mesh.

8. The preparation method of a coal-tar-based nitrogen and sulfur co-doped porous carbon material according to claim 1, characterized in that, The crustacean substances use the shells of shrimp and crab shells.

9. The preparation method of a coal-tar-based nitrogen and sulfur co-doped porous carbon material according to claim 1, characterized in that, The total specific surface area of the coal-tar-based nitrogen-sulfur co-doped porous carbon material reaches 2983 m 2 / g, the micropore specific surface area reaches 2123 m 2 / g, and the mesopore specific surface area reaches 860 m 2 / g.

10. A nitrogen and sulfur co-doped porous carbon material based on coal tar, prepared by the preparation method of a nitrogen and sulfur co-doped porous carbon material based on coal tar according to any one of claims 1 - 9.

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