Porous carbon material and preparation method thereof

Abstract

The embodiment of the invention relates to a porous carbon material and a preparation method thereof. The preparation method comprises the following steps: adding a resin carbon source and a mixed carbon source into absolute ethyl alcohol, and uniformly stirring to form a first solution; dissolving an auxiliary additive in water to form a solution, and adding absolute ethyl alcohol into the solution to obtain a uniformly dispersed second solution; adding the second solution into the first solution, uniformly stirring, grinding and mixing to obtain a first mixed solution; adding soluble metal salt into the first mixed solution, stirring, mixing and dipping to form a second mixed solution; the second mixed solution is dried in a spray drying mode, and a spherical powdery substance formed by mixing metal salt and carbon is obtained; and sintering the spherical powdery substance in a rotary furnace in an inert atmosphere to form the porous carbon material.

Description

Technical Field

[0001] The present invention relates to the technical field of material preparation, and particularly to a porous carbon material and a preparation method thereof. Background Art

[0002] Porous carbon is a carbon material with a porous structure and is widely used in fields such as catalysis, adsorption, electrochemistry, and energy. The performance of porous carbon is closely related to factors such as its pore structure, specific surface area, pore volume, pore size distribution, and surface functional groups. Therefore, developing simple, efficient, and environmentally friendly preparation methods for porous carbon, as well as regulating the structure and performance of porous carbon, is an important direction in the research of porous carbon.

[0003] In many applications, composite materials of resin-based porous carbon loaded with metal nanoparticles have a wide range of uses, including catalysis, electrochemistry, adsorption, etc. However, traditional methods for preparing such composite materials often have high costs and some technical challenges. Currently, the main way to prepare resin porous carbon is simple heat treatment. However, the resulting porous carbon material has a relatively low specific surface area, which limits its performance and application value in some applications. First, for many applications, the control of the porous structure is crucial, but traditional methods are difficult to control the pore structure. Second, for the distribution and stability of metal nanoparticles, traditional preparation methods cannot provide ideal results. Third, different applications have quite different requirements for material performance, and traditional methods usually have difficulty meeting diverse needs.

[0004] Therefore, it is necessary to find new and more effective preparation methods to overcome the limitations of traditional methods and ensure that the resulting materials can better meet the requirements of different applications. Summary of the Invention

[0005] The object of the present invention is to provide a porous carbon material and a preparation method thereof to solve the problems of high cost, difficult structure control, uneven loading, etc. in traditional methods, and to provide an economical, efficient, and highly controllable solution for preparing resin-based porous carbon loaded with metal nanoparticles.

[0006] To this end, in a first aspect, an embodiment of the present invention provides a preparation method of a porous carbon material, and the preparation method includes:

[0007] Adding a resin carbon source and a mixed carbon source to absolute ethanol, stirring evenly to form a first solution;

[0008] Dissolving an auxiliary additive in water first to form a solution, and then adding absolute ethanol to the solution to obtain a second solution with uniform dispersion;

[0009] Adding the second solution to the first solution, stirring evenly, and performing grinding and mixing to obtain a first mixed solution;

[0010] Add a soluble metal salt to the first mixed solution and stir and mix it for impregnation to form a second mixed solution;

[0011] Dry the second mixed solution by spray drying to obtain a spherical powdery substance of a metal salt and carbon mixture;

[0012] Place the spherical powdery substance in a rotary furnace for sintering under an inert atmosphere to form the porous carbon material.

[0013] Preferably, in the first solution, the mass ratio of the resin carbon source to the mixed carbon source is 3:1 to 5:1, and the total mass ratio of the resin carbon source and the mixed carbon source to the mass of absolute ethanol is 1:3 to 1:6.

[0014] Preferably, the resin carbon source includes one or more of phenolic resin, epoxy resin, melamine resin, or acrylic resin; the mixed carbon source includes glucose or sucrose; by adding the resin carbon source, the structural stability of the porous carbon material is improved; by adding the mixed carbon source, the porosity and specific surface area of the obtained porous carbon material are improved.

[0015] Preferably, the auxiliary additive includes one or more of polyvinylpyrrolidone PVP, urea, or polyethylene glycol;

[0016] The mass ratio of the auxiliary additive to the total mass of the resin carbon source and the mixed carbon source is 1:8 to 1:2.

[0017] Preferably, in the second solution, the mass ratio of water to absolute ethanol is 1:1.

[0018] Preferably, the grinding and mixing are carried out in a sand mill, the main machine speed of the sand mill is 1000 - 1300 revolutions per minute, the separation speed is 1400 - 1700 revolutions per minute, and the grinding time is 1 - 5 h.

[0019] Preferably, the soluble metal salt includes one or several of soluble copper salt, soluble aluminum salt, soluble cobalt salt, soluble nickel salt, soluble iron salt, and soluble manganese salt;

[0020] The impregnation time is 3 - 24 h.

[0021] Preferably, the sintering specifically includes: heating at a heating rate of 2 - 10 °C / min to 300 - 600 °C, then holding for 3 - 10 h to volatilize the auxiliary additive to form pores; then heating at a heating rate of 2 - 10 °C / min to a high temperature of 900 - 1200 °C, and holding for 3 - 10 h, so that the metal salt decomposed by heat is reduced to metal nanoparticles by carbon at high temperature and loaded into the pores.

[0022] In a second aspect, an embodiment of the present invention provides a porous carbon material prepared by the preparation method described in the first aspect above.

[0023] Preferably, metal nanoparticles are loaded in the pores of the porous carbon material.

[0024] The preparation method provided by the embodiment of the present invention can achieve precise control of the porous structure by introducing a suitable auxiliary additive and controlling the addition amount, so that the final porous carbon material has a tunable pore structure and is suitable for the needs of different application fields. By reducing metal salts to metal nanoparticles and loading them on the porous carbon structure during the high-temperature reduction process, an effective method for achieving uniform distribution and high stability of metal nanoparticles is provided. The present invention provides an economical, efficient and controllable solution for preparing resin porous carbon and loading metal nanoparticles. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a flowchart of the preparation method of the porous carbon material provided by the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The technical solutions of the present invention will be further described in detail below with reference to the drawings and embodiments.

[0027] An embodiment of the present invention provides a porous carbon material, and the main steps of its preparation method are as Figure 1 shown, including:

[0028] Step 110: Add the resin carbon source and the mixed carbon source to absolute ethanol, stir evenly to form a first solution;

[0029] In the first solution, the mass ratio of the resin carbon source to the mixed carbon source is 3:1 to 5:1, and the mass ratio of the total mass of the resin carbon source and the mixed carbon source to the mass of absolute ethanol is 1:3 to 1:6.

[0030] The resin carbon source may include one or more of phenolic resin, epoxy resin, melamine resin or acrylic resin; the mixed carbon source may include glucose or sucrose.

[0031] By adding the resin carbon source, the structural stability of the porous carbon material is improved, and by adding the mixed carbon source, the porosity and specific surface area of the obtained porous carbon material are improved. At the same time, further, because the mixed carbon source selected by the present invention has a low cost and is easy to obtain, adding a certain amount of the mixed carbon source can also reduce the cost.

[0032] Step 120: First dissolve the auxiliary additive in water to form a solution, and then add absolute ethanol equal to the amount of water to the solution to obtain a uniformly dispersed second solution;

[0033] The auxiliary additives include one or more of polyvinylpyrrolidone (PVP), urea, and polyethylene glycol; the mass ratio of the auxiliary additive to the total mass of the resin carbon source and the mixed carbon source is 1:8 to 1:2. By changing the addition amount of the auxiliary additive, the morphology of the finally obtained porous carbon can be controlled and changed to obtain porous carbon with different porosities, so as to meet different needs. Through this method, the preparation of porous carbon with different morphology requirements can be simply and effectively realized.

[0034] Preferably, in the second solution, the mass ratio of water to absolute ethanol is 1:1.

[0035] In this step, the auxiliary additive is first dissolved in water to form a solution and then absolute ethanol is added. This is mainly because some of the selected auxiliary additives can be directly dissolved in ethanol, while some are insoluble in ethanol. However, since the main carbon source, the resin carbon source, is soluble in ethanol but insoluble in water, therefore, the water-soluble auxiliary additive is first uniformly dispersed in water and then ethanol is added, so as to achieve miscibility with the first solution in step 110.

[0036] Step 130, add the second solution to the first solution, stir evenly, and perform grinding and mixing to obtain a first mixed solution;

[0037] The grinding and mixing is carried out in a sand mill. The main machine speed of the sand mill is 1000 - 1300 revolutions per minute, the separation speed is 1400 - 1700 revolutions per minute, and the grinding time is 1 - 5 hours.

[0038] Step 140, add a soluble metal salt to the first mixed solution and perform stirring and mixing, impregnation, to form a second mixed solution;

[0039] The soluble metal salt includes one or several of soluble copper salts, soluble aluminum salts, soluble cobalt salts, soluble nickel salts, soluble iron salts, and soluble manganese salts; the impregnation time is 3 - 24 hours.

[0040] Step 150, dry the second mixed solution by spray drying to obtain a spherical powdery substance mixed with metal salt and carbon;

[0041] The specific conditions for spray drying are: set the inlet air temperature to 145°C - 185°C, the outlet air temperature to 60°C - 100°C, and the frequency of the atomizer to 200 Hz.

[0042] Step 160, place the spherical powdery substance in a rotary furnace for sintering under an inert atmosphere to form a porous carbon material.

[0043] The inert atmosphere is preferably a nitrogen or argon atmosphere.

[0044] The sintering specifically includes: heating at a heating rate of 2 - 10 °C / min to 300 - 600 °C, then holding for 3 - 10 h to volatilize the auxiliary additive to form pores; then heating at a heating rate of 2 - 10 °C / min to a high temperature of 900 - 1200 °C and holding for 3 - 10 h, so that the metal salt decomposed by heat is reduced to metal nanoparticles by carbon at high temperature and loaded into the pores.

[0045] The preparation method provided by the invention embodiment can achieve precise control of the porous structure by introducing a suitable auxiliary additive and controlling the addition amount, so that the final porous carbon material has a tunable pore structure and is suitable for the needs of different application fields. By reducing metal salts to metal nanoparticles during the high-temperature reduction process and loading them on the porous carbon structure, an effective method for achieving uniform distribution and high stability of metal nanoparticles is provided. The present invention provides an economical, efficient and controllable solution for preparing resin porous carbon and loading metal nanoparticles. Using the preparation method of the present invention reduces the demand for expensive raw materials, reduces the energy consumption in the production process, and helps to achieve an economical and environmentally friendly preparation process.

[0046] The resin porous carbon prepared by the present invention can be used in multiple application fields, including but not limited to catalysis, electrochemistry, adsorption, etc. Its performance can be customized by adjusting the specific resin carbon source, mixed carbon source, addition amount of auxiliary additive and preparation conditions, etc. to meet the needs of different fields and applications.

[0047] In order to more clearly illustrate the purpose and advantages of the present invention, the present invention will be further described below in conjunction with embodiments. In addition, the embodiments described in the present invention are only partial embodiments. All other embodiments obtained by those skilled in the art without creative work based on the embodiments described in the present invention fall within the protection scope of the present invention. In addition, it should be understood that these embodiments are only used for more detailed description and should not be construed as limiting the present invention in any form, that is, it is not intended to limit the protection scope of the present invention.

[0048] Example 1

[0049] In this example, a porous carbon material was prepared. The specific method is as follows:

[0050] S1: Add 30 kg of phenolic resin and 10 kg of glucose to 160 kg of absolute ethanol and stir evenly.

[0051] S2: Dissolve 5 kg of PVP in 10 kg of deionized water, then add 10 kg of ethanol for mixing, and stir with a disperser at 1000 revolutions per minute for 1 hour.

[0052] S3: Add the solution prepared in S2 to the solution prepared in S1. After stirring evenly, use a sand mill to grind and mix thoroughly. The grinding conditions are: the main machine speed is 1200 revolutions per minute, the separation speed is 1700 revolutions per minute, and grind for 1 hour.

[0053] S4: Add 1 kg of anhydrous copper sulfate to the above-mentioned ground mixed solution. The mass ratio of copper ions to the total carbon source is about 1:100. Stir and mix, and impregnate for 12 hours.

[0054] S5: Dry the mixed solution by spray drying to obtain a spherical powdery substance of metal salt and carbon mixture. The spray drying conditions are: the inlet air temperature is 165 °C, the outlet air temperature is 85 °C, and the atomizer frequency is 200 Hz.

[0055] S6: Under a nitrogen inert atmosphere, place the spherical powdery substance of metal salt and carbon mixture in a rotary furnace for sintering. The sintering conditions are: heat up to 800 °C at a heating rate of 3 °C / min, hold for 6 hours, and naturally cool to room temperature to obtain the porous carbon material required in this example.

[0056] Example 2

[0057] A porous carbon material was prepared in this example. The specific method is as follows:

[0058] S1: Add 30 kg of phenolic resin and 10 kg of glucose to 160 kg of anhydrous ethanol and stir evenly.

[0059] S2: Dissolve 10 kg of PVP in 10 kg of deionized water, then add 10 kg of ethanol for mixing, and stir with a disperser at 1000 revolutions per minute for 1 hour.

[0060] S3: Add the solution prepared in S2 to the solution prepared in S1. After stirring evenly, use a sand mill to grind and mix thoroughly. The grinding conditions are: the main machine speed is 1200 revolutions per minute, the separation speed is 1700 revolutions per minute, and grind for 1 hour.

[0061] S4: Add 1 kg of anhydrous copper sulfate to the above-mentioned ground mixed solution. The mass ratio of copper ions to the total carbon source is about 1:100. Stir and mix, and impregnate for 12 hours.

[0062] S5: Dry the mixed solution by spray drying to obtain a spherical powdery substance of metal salt and carbon mixture. The spray drying conditions are: the inlet air temperature is 165 °C, the outlet air temperature is 85 °C, and the atomizer frequency is 200 Hz.

[0063] S6: In a nitrogen inert atmosphere, the spherical powdery substance of the metal salt and carbon mixture is placed in a rotary furnace for sintering. Sintering conditions: heating up to 800 °C at a heating rate of 3 °C / min, holding for 6 hours, and naturally cooling to room temperature to obtain the porous carbon material required for this example.

[0064] Example 3

[0065] In this example, a porous carbon material was prepared. The specific method is as follows:

[0066] S1: Add 30 kg of phenolic resin and 10 kg of glucose to 160 kg of absolute ethanol and stir evenly.

[0067] S2: Dissolve 5 kg of polyethylene glycol in 10 kg of deionized water, then add 10 kg of ethanol for mixing, and stir with a disperser at 1000 revolutions per minute for 1 hour.

[0068] S3: Add the solution prepared in S2 to the solution prepared in S1, stir evenly, and then use a sand mill to grind and mix thoroughly. The grinding conditions are: the main machine speed is 1200 revolutions per minute, the separation speed is 1700 revolutions per minute, and grind for 1 hour.

[0069] S4: Add 1 kg of anhydrous copper sulfate to the above-ground mixed solution. The mass ratio of copper ions to the total carbon source is about 1:100, stir and mix, and impregnate for 12 hours.

[0070] S5: Dry the mixed solution by spray drying to obtain a spherical powdery substance of the metal salt and carbon mixture. The spray drying conditions are: the inlet air temperature is 165 °C, the outlet air temperature is 85 °C, and the atomizer frequency is 200 Hz.

[0071] S6: In a nitrogen inert atmosphere, the spherical powdery substance of the metal salt and carbon mixture is placed in a rotary furnace for sintering. Sintering conditions: heating up to 800 °C at a heating rate of 3 °C / min, holding for 6 hours, and naturally cooling to room temperature to obtain the porous carbon material required for this example.

[0072] Example 4

[0073] In this example, a porous carbon material was prepared. The specific method is as follows:

[0074] S1: Add 30 kg of phenolic resin and 10 kg of glucose to 160 kg of absolute ethanol and stir evenly.

[0075] S2: Dissolve 5 kg of PVP in 10 kg of deionized water, then add 10 kg of ethanol for mixing, and stir with a disperser at 1000 revolutions per minute for 1 hour.

[0076] S3: Add the solution prepared in S2 to the solution prepared in S1. After stirring evenly, use a sand mill to grind and mix thoroughly. The grinding conditions are as follows: the main machine speed is 1200 revolutions per minute, the separation speed is 1700 revolutions per minute, and grind for 1 hour.

[0077] S4: Add 2 kg of anhydrous copper sulfate to the above-mentioned ground mixed solution. The mass ratio of copper ions to the total mass of the carbon source is about 1:50. Stir and mix, and impregnate for 12 hours.

[0078] S5: Dry the mixed solution by spray drying to obtain a spherical powdery substance of metal salt and carbon mixture. The spray drying conditions are: the inlet air temperature is 165 °C, the outlet air temperature is 85 °C, and the atomizer frequency is 200 Hz.

[0079] S6: Under a nitrogen inert atmosphere, place the spherical powdery substance of metal salt and carbon mixture in a rotary furnace for sintering. The sintering conditions are: heat up to 800 °C at a heating rate of 3 °C / min, hold for 6 hours, and naturally cool to room temperature to obtain the porous carbon material required in this example.

[0080] The present invention also provides two comparative examples for technical comparison with the above-mentioned examples.

[0081] Comparative Example 1

[0082] In this comparative example, porous carbon is directly prepared by spraying phenolic resin material. The steps include:

[0083] S1: Add 30 kg of phenolic resin to 120 kg of absolute ethanol and stir evenly.

[0084] S2: Dry the solution by spray drying. The spray conditions are: the inlet air temperature is 165 °C, the outlet air temperature is 85 °C, and the atomizer frequency is 200 Hz to obtain spherical phenolic resin powder.

[0085] S3: Under a nitrogen inert atmosphere, place the powdery substance in a rotary furnace for sintering. The sintering conditions are: heat up to 800 °C at a heating rate of 3 °C / min, hold for 6 hours, and naturally cool to room temperature to obtain the comparative porous carbon.

[0086] Comparative Example 2

[0087] In this comparative example, porous carbon is prepared by adding metal salt without adding auxiliary additives. The steps include:

[0088] S1: Add 30 kg of phenolic resin and 10 kg of glucose to 160 kg of absolute ethanol and stir evenly.

[0089] S2: Add 1 kg of anhydrous copper sulfate to the solution. The mass ratio of copper ions to the carbon source is 1:100. Stir and mix, and impregnate for 12 h;

[0090] S3: Dry the mixed solution by spray drying to obtain a spherical powdery substance of metal salt and carbon. The spray conditions are as follows: the inlet air temperature is 165 °C, the outlet air temperature is 85 °C, and the atomizer frequency is 200 Hz.

[0091] S6: Place the powdery substance in a rotary furnace for sintering under an inert atmosphere. The sintering conditions are as follows: heat up to 800 °C at a heating rate of 3 °C / min, hold for 6 hours, and then cool naturally to room temperature to obtain porous carbon loaded with metal salt.

[0092] Perform specific surface area test analysis and energy dispersive X-ray spectroscopy (EDS) elemental analysis on the obtained materials. The results are shown in Table 1 and Table 2 respectively as follows.

[0093] Table 1 shows the specific surface area and pore size of the materials in Examples 1-4.

[0094] Number <![CDATA[Specific surface area m 2 / g]]> Aperture nm Example 1 965.23 2.51 Example 2 1297.64 5.84 Example 3 1102.33 3.39 Example 4 976.41 2.27 Comparative Example 318.95 1.36

[0095] As can be seen from Table 1, the addition of the auxiliary additive helps to form pores. In Examples 1 and 2, due to different addition amounts of PVP, materials with different specific surface areas and pore sizes are obtained. After the addition amount of PVP is doubled, the specific surface area increases and the pore size also expands. The addition of the auxiliary additive mainly affects the pore structure of the material, and then affects the properties of the specific surface area and pore size.

[0096] Table 2 shows the test data of the metal element content in the materials of Example 1 and Comparative Example 2.

[0097] Number Carbon element content (proportion) Copper element content (proportion) Example 1 99.8％ 0.2％ Comparative Example 2 99.1％ 0.8％

[0098] As can be seen from Table 2, comparing Example 1 and Comparative Example 2, the addition of the auxiliary additive increases the loading amount of the metal salt. On the one hand, the use of the auxiliary additive can increase the specific surface area of the material and improve the available surface area for metal loading. This may help to increase the deposition surface of the metal salt and improve the metal loading amount. On the other hand, the use of the auxiliary additive can regulate the pore structure of the material to form more or larger pores, thus providing more metal nucleation sites for metal deposition. This helps to increase the dispersion and loading amount of the metal.

[0099] In addition, the auxiliary additive can also provide a template effect, promoting the deposition of the metal salt at specific positions, helping to form an ordered structure, and thus improving the metal loading efficiency.

[0100] The specific embodiments described above further elaborate on the object, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only the specific embodiments of the present invention and is not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation method of a porous carbon material, characterized in that, the preparation method includes: Adding a resin carbon source and a mixed carbon source into absolute ethanol, stirring evenly to form a first solution; Dissolving an auxiliary additive in water first to form a solution, and then adding absolute ethanol to the solution to obtain a second solution with uniform dispersion; Adding the second solution to the first solution, stirring evenly, and performing grinding and mixing to obtain a first mixed solution; Adding a soluble metal salt to the first mixed solution, stirring and mixing, and impregnating to form a second mixed solution; Drying the second mixed solution by spray drying to obtain a spherical powdery substance of a metal salt and carbon mixture; Under an inert atmosphere, placing the spherical powdery substance in a rotary furnace for sintering to form the porous carbon material.

2. The preparation method according to claim 1, characterized in that, In the first solution, the mass ratio of the resin carbon source to the mixed carbon source is 3:1 to 5:1, and the ratio of the total mass of the resin carbon source and the mixed carbon source to the mass of absolute ethanol is 1:3 to 1:

6.

3. The preparation method according to claim 1, characterized in that, The resin carbon source includes: one or more of phenolic resin, epoxy resin, melamine resin or acrylic resin; the mixed carbon source includes: glucose or sucrose; by adding the resin carbon source, the structural stability of the porous carbon material is improved; by adding the mixed carbon source, the porosity and specific surface area of the obtained porous carbon material are improved.

4. The preparation method according to claim 1, characterized in that, The auxiliary additive includes: one or more of polyvinylpyrrolidone PVP, urea, polyethylene glycol; The mass ratio of the auxiliary additive to the total mass of the resin carbon source and the mixed carbon source is 1:8 to 1:

2.

5. The preparation method according to claim 1, characterized in that, In the second solution, the mass ratio of water to absolute ethanol is 1:

1.

6. The preparation method according to claim 1, characterized in that, The grinding and mixing is carried out in a sand mill, the main machine speed of the sand mill is 1000 - 1300 revolutions per minute, the separation speed is 1400 - 1700 revolutions per minute, and the grinding time is 1 - 5 hours.

7. The preparation method according to claim 1, characterized in that, The soluble metal salt includes one or several of soluble copper salt, soluble aluminum salt, soluble cobalt salt, soluble nickel salt, soluble iron salt and soluble manganese salt; The impregnation time is 3 - 24 hours.

8. The preparation method according to claim 1, characterized in that, The sintering specifically includes: heating at a heating rate of 2 - 10 °C / min to 300 - 600 °C, and then holding for 3 - 10 hours to volatilize the auxiliary additive to form pores; then heating at a heating rate of 2 - 10 °C / min to a high temperature of 900 - 1200 °C, and holding for 3 - 10 hours, so that the metal salt decomposed by heat is reduced to metal nanoparticles by carbon at high temperature and loaded into the pores.

9. A porous carbon material prepared by the preparation method according to any one of claims 1 - 8 above.

10. The porous carbon material according to claim 9 above, characterized in that, metal nanoparticles are loaded in the pores of the porous carbon material.

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