A phenolic resin-based mesoporous carbon and its preparation method

Abstract

This invention relates to the field of molecular sieve materials, and particularly to a phenolic resin-based mesoporous carbon and its preparation method. By weight, the raw materials include 100 parts phenolic resin, 5-30 parts surfactant, 10-35 parts paraffin, and 5-50 parts acid. The phenolic resin is obtained by addition and condensation reactions of phenol and formaldehyde under alkaline conditions at a temperature of 75-90°C. The preparation method of the phenolic resin-based mesoporous carbon provided by this invention is simple and easy to operate. By using phenol and formaldehyde to synthesize a phenolic resin of a certain molecular weight as a precursor, the pore structure and pore size of the obtained phenolic resin-based mesoporous carbon material are controllable, achieving a uniform nanoscale microporous structure and a high specific surface area, which is beneficial for improving material performance.

Description

Technical Field

[0001] This invention relates to the field of molecular sieve materials, and in particular to a phenolic resin-based mesoporous carbon and its preparation method. Background Technology

[0002] Mesoporous carbon materials refer to porous carbon materials with pore sizes ranging from 2 to 50 nm. They possess advantages such as high specific surface area and porosity, adjustable pore size within a certain range, diverse mesopore shapes, and high thermal stability. Furthermore, they are simple to synthesize, easy to handle, and non-physiologically toxic. Due to their excellent properties, they have enormous application value in fields such as fuel cells, molecular sieves, adsorption, catalysis, and electrochemistry. In recent years, mesoporous materials science has become one of the hottest research areas internationally, intersecting with chemistry, physics, materials science, and biology, and has become a significant milestone in the development of materials science.

[0003] Currently, the main methods for synthesizing mesoporous carbon include soft-templating, hard-templating, and self-templating or template-free methods. Among these, the soft-templating method involves the self-assembly of a carbon precursor and a surfactant through interactions such as hydrogen bonding, followed by polymerization, carbonization, and template removal steps to finally obtain the mesoporous carbon material. However, because the organic-organic self-assembly process often requires a high precursor / template ratio to obtain a mesoscopically ordered composite liquid crystal phase structure, the prepared mesoporous carbon material has a relatively thick wall. Furthermore, the polymer framework shrinks significantly during carbonization, which is detrimental to the preservation of the microporous structure. Therefore, the mesoporous carbon material obtained by this method typically has a low specific surface area and a wide pore size distribution. Summary of the Invention

[0004] To address the shortcomings of existing mesoporous carbon materials, such as low specific surface area and wide pore size distribution, this invention provides a phenolic resin-based mesoporous carbon and its preparation method.

[0005] This invention provides a phenolic resin-based mesoporous carbon, which, by weight, comprises 100 parts of phenolic resin, 5-30 parts of surfactant, 10-35 parts of paraffin, and 5-50 parts of acid; wherein the phenolic resin is obtained by addition and condensation reaction of phenol and formaldehyde under alkaline conditions.

[0006] Furthermore, the specific method for preparing the phenolic resin is as follows: phenol and formaldehyde are added to a reaction vessel, an alkaline solution is added to adjust the pH of the system to 8-10, the reaction temperature is adjusted to 75-90℃, and the reaction is carried out for 3-10 hours.

[0007] Furthermore, the molar ratio of phenol to formaldehyde is 1:(1.4-2).

[0008] Furthermore, the phenolic resin has a molecular weight of 500-1000 and a viscosity of 5000-25000 mPa·s.

[0009] Furthermore, the surfactant is one of Tween, hydrogenated castor oil polyoxyethylene ether, and fatty alcohol polyoxyethylene ether.

[0010] Furthermore, the acid is at least one of p-toluenesulfonic acid, methanesulfonic acid, and phenolsulfonic acid.

[0011] The present invention also provides a method for preparing the above-mentioned phenolic resin-based mesoporous carbon, comprising the following steps:

[0012] S1. Stir and mix the phenolic resin, surfactant, paraffin and acid, and cure at 50-80℃ for 20-60 min to obtain cured phenolic resin.

[0013] S2. The cured phenolic resin is placed in a furnace and pre-carbonized at 300-450°C with a heating rate of 1-5°C / min under nitrogen protection. Then, it is carbonized at 800-900°C with a heating rate of 3-8°C / min to obtain the phenolic resin-based mesoporous carbon.

[0014] Furthermore, the pre-carbonization time is 2-10 hours, and the carbonization time is 2-10 hours.

[0015] Compared with the prior art, the method for preparing phenolic resin-based mesoporous carbon provided by the present invention is simple and easy to operate. By synthesizing a phenolic resin of a certain molecular weight from phenol and formaldehyde as a precursor, the pore structure and pore size of the obtained phenolic resin-based mesoporous carbon material are controllable, achieving a uniform nanoscale microporous structure and a high specific surface area, which is beneficial to improving the material performance. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] This invention provides a phenolic resin-based mesoporous carbon, which, by weight, comprises 100 parts of phenolic resin, 5-30 parts of surfactant, 10-35 parts of paraffin, and 5-50 parts of acid.

[0018] The phenolic resin is obtained by addition and condensation reaction of phenol and formaldehyde under alkaline conditions and at a temperature of 75-90°C.

[0019] The present invention also provides a method for preparing the above-mentioned phenolic resin-based mesoporous carbon, comprising the following steps:

[0020] S1. Stir and mix the phenolic resin, surfactant, paraffin and acid, and cure at 50-80℃ for 20-60 min to obtain cured phenolic resin.

[0021] S2. The cured phenolic resin is placed in a furnace and pre-carbonized for 2-10 hours at a heating rate of 1-5℃ / min to 300-450℃ under nitrogen protection. Then, it is carbonized for 2-10 hours at a heating rate of 3-8℃ / min to 800-900℃ to obtain the phenolic resin-based mesoporous carbon.

[0022] The present invention provides the following raw material composition for embodiments and comparative examples, as shown in Table 1:

[0023] Table 1

[0024] Example 1 Example 2 Example 3 Comparative Example 1 Phenolic resin 100 100 100 100 surfactants 20 5 30 20 paraffin 18 10 35 0 acid 35 5 50 35

[0025] The present invention provides the following preparation methods for embodiments and comparative examples:

[0026] Example 1

[0027] (1) Preparation of phenolic resin:

[0028] Phenol and formaldehyde were added to a reaction vessel in a molar ratio, sodium hydroxide solution was added to adjust the pH of the system to 8, the reaction temperature was adjusted to 75℃, and the reaction was carried out for 10 hours to obtain a phenolic resin with a molecular weight of 1000 and a viscosity of 20000 mPa·s.

[0029] (2) Preparation of phenolic resin-based mesoporous carbon

[0030] S1. Mix 100 parts of the phenolic resin obtained in step (1), 20 parts of Tween, 18 parts of paraffin and 35 parts of p-toluenesulfonic acid, and cure at 50°C for 60 minutes to obtain cured phenolic resin.

[0031] S2. The cured phenolic resin is placed in a tube furnace and pre-carbonized for 6 hours at a heating rate of 1℃ / min to 300℃ under nitrogen protection. Then, the temperature is increased to 800℃ at a heating rate of 3℃ / min for carbonization for 8 hours to obtain the phenolic resin-based mesoporous carbon.

[0032] Example 2

[0033] (1) Preparation of phenolic resin:

[0034] Phenol and formaldehyde were added to a reaction vessel in a molar ratio, sodium hydroxide solution was added to adjust the pH of the system to 10, the reaction temperature was adjusted to 80℃, and the reaction was carried out for 5 hours to obtain a phenolic resin with a molecular weight of 600 and a viscosity of 18000 mPa·s.

[0035] (2) Preparation of phenolic resin-based mesoporous carbon

[0036] S1. Mix 100 parts of the phenolic resin obtained in step (1), 5 parts of hydrogenated castor oil polyoxyethylene ether, 10 parts of paraffin and 5 parts of phenol sulfonic acid, and cure at 70°C for 40 min to obtain cured phenolic resin.

[0037] S2. The cured phenolic resin is placed in a tube furnace and pre-carbonized for 2 hours at a heating rate of 3°C / min to 380°C under nitrogen protection. Then, the temperature is increased to 850°C at a heating rate of 6°C / min for carbonization for 10 hours to obtain the phenolic resin-based mesoporous carbon.

[0038] Example 3

[0039] (1) Preparation of phenolic resin:

[0040] Phenol and formaldehyde were added to a reaction vessel in a molar ratio, potassium hydroxide solution was added to adjust the pH of the system to 9, the reaction temperature was adjusted to 90℃, and the reaction was carried out for 3 hours to obtain a phenolic resin with a molecular weight of 500 and a viscosity of 15000 mPa·s.

[0041] (2) Preparation of phenolic resin-based mesoporous carbon

[0042] S1. Mix 100 parts of the phenolic resin obtained in step (1), 30 parts of hydrogenated castor oil polyoxyethylene ether, 35 parts of paraffin and 50 parts of phenol sulfonic acid, and cure at 80°C for 20 minutes to obtain cured phenolic resin.

[0043] S2. The cured phenolic resin is placed in a tube furnace and pre-carbonized for 10 hours at a heating rate of 5°C / min to 450°C under nitrogen protection. Then, the temperature is increased to 900°C at a heating rate of 8°C / min for carbonization for 2 hours to obtain the phenolic resin-based mesoporous carbon.

[0044] Comparative Example 1

[0045] Unlike Example 1, no paraffin was added, but the other raw materials and processes were the same as in Example 1.

[0046] Comparative Example 2

[0047] Unlike Example 1, the phenolic resin obtained in step (1) was replaced by an equal mass of commercially available phenolic resin.

[0048] Comparative Example 3

[0049] Unlike Example 1, step S2 does not involve pre-carbonization. Instead, the cured phenolic resin is heated to 800°C for 14 hours under nitrogen protection at a heating rate of 3°C / min. The remaining raw materials and processes are the same as in Example 1.

[0050] Comparative Example 4

[0051] Unlike Example 1, in step S2, the tubular furnace is heated to 500°C at a heating rate of 1°C / min for pre-carbonization for 6 hours, while the remaining raw materials and processes are the same as in Example 1.

[0052] Comparative Example 5

[0053] Unlike Example 1, the phenolic resin obtained in step (1) has a molecular weight of 1200, while the other raw materials and processes are the same as in Example 1.

[0054] The specific surface area of ​​the phenolic resin-based mesoporous carbon prepared in the examples and comparative examples was tested using the BET method, and the pore volume and average pore diameter were tested using the BJH method. The test results are shown in Table 2.

[0055] Table 2

[0056] <![CDATA[Specific surface area m 2 / g]]> pore volume (ml / g) Average pore size (nm) Example 1 2599.69 1.76 2.68 Example 2 2374.35 1.58 2.46 Example 3 2716.51 1.82 2.68 Comparative Example 1 2045.31 1.03 2.02 Comparative Example 2 2475.54 1.69 2.61 Comparative Example 3 1840.0 1.03 3.56 Comparative Example 4 2503.12 1.68 2.56 Comparative Example 5 2305.21 2.30 5.26

[0057] As can be seen from Table 2, the phenolic resin-based mesoporous carbon provided in the embodiments of the present invention has a high specific surface area (2300 m²). 2 The material exhibits a high pore size (≥1.58 ml / g) and a large pore volume, and electron microscopy reveals uniform pore size and interpore spacing. The preparation method provided by this invention allows for controlling the pore size of the material to 2-3 nm, resulting in highly active material suitable for wide application.

[0058] The comparison results between Comparative Example 1 and Example 1 show that without the addition of paraffin, the pore volume and pore size of the mesoporous carbon material are reduced, resulting in a significant decrease in the specific surface area of ​​the material. This indicates that the addition of paraffin helps to form pores inside the phenolic resin and increases the specific surface area of ​​the mesoporous carbon material.

[0059] The comparison results of Comparative Examples 2 and 5 and Example 1 show that the present invention uses phenol and formaldehyde in a specific molar ratio to prepare a phenolic resin with a certain molecular weight and viscosity as a carbon source. Compared with commercially available phenolic resins, it has higher reactivity, which helps to control the pore structure and pore size. The resulting mesoporous carbon material has a higher specific surface area.

[0060] The comparison results of Comparative Examples 3 and 4 and Example 1 show that pre-carbonization at a specific temperature followed by carbonization helps to control the pore structure and pore size, and improve the pore volume and specific surface area of ​​the material.

[0061] The specific parameters or some commonly used reagents or raw materials in the above embodiments are specific or preferred embodiments under the concept of the present invention, and are not intended to limit it; those skilled in the art can make adaptive adjustments within the concept and protection scope of the present invention. Furthermore, unless otherwise specified, the above raw materials are all commercially available or prepared by conventional methods.

[0062] In addition, unless otherwise specified, the raw materials used may be commercially available products in the field or prepared by conventional methods in the field.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a phenolic resin-based mesoporous carbon, characterized by: The method comprises the following steps: S1, stirring and mixing phenolic resin, surfactant, paraffin and acid, curing at 50-80℃ for 20-60min to obtain cured phenolic resin; S2, placing the cured phenolic resin in a furnace, pre-carbonizing at 300-450℃ with a temperature rising rate of 1-5℃ / min under the protection of nitrogen, and then carbonizing at 800-900℃ with a temperature rising rate of 3-8℃ / min to obtain the phenolic resin-based mesoporous carbon; The raw materials include phenolic resin 100 parts, surfactant 5-30 parts, paraffin 10-35 parts and acid 5-50 parts by weight; The preparation method of the phenolic resin comprises the following steps: putting phenol and formaldehyde into a reaction container, adding an alkaline solution to adjust the pH value of the system to 8-10, adjusting the reaction temperature to 75-90℃, and reacting for 3-10h; The molar ratio of the phenol and formaldehyde is 1:(1.4-2); The molecular weight of the phenolic resin is 500-1000, and the viscosity is 5000-25000mPa·s.

2. The method for preparing a phenolic resin-based mesoporous carbon according to claim 1, characterized by: The pre-carbonization time is 2-10h, and the carbonization time is 2-10h.

3. The method for preparing phenolic resin-based mesoporous carbon according to claim 1, characterized in that: The surfactant is one of Tween, hydrogenated castor oil polyoxyethylene ether and fatty alcohol polyoxyethylene ether.

4. The method for preparing phenolic resin-based mesoporous carbon according to claim 1, characterized in that: The acid is at least one of p-toluenesulfonic acid, methylsulfonic acid and phenol sulfonic acid.