CN112897505B - A kind of preparation method of mesoporous carbon material - Google Patents

Abstract

The present invention relates to a preparation method of mesoporous carbon material. It includes the following steps: (1) preparation of a phenolic resin precursor solution; (2) blending of the precursor and a template agent; (3) curing; (4) carbonization; (5) post-treatment. After mixing and curing the phenolic resin precursor and the template agent in a certain proportion, it is placed in an inert gas atmosphere to program the temperature to remove the template agent and carbonize the phenolic resin. The carbonized product is pulverized, washed, removed, filtered and dried. , to obtain mesoporous carbon materials. The template agent used in the invention has wide sources, is cheap and easy to obtain, the preparation method is simple, and the prepared mesoporous carbon has the advantages of controllable pore size, uniform pore channel, stable structure, etc.

Description

A kind of preparation method of mesoporous carbon material

technical field

The invention belongs to the field of carbon materials, and relates to a preparation method of a mesoporous carbon material.

Background technique

In recent years, there has been a great deal of interest in the study of carbon nanomaterials and their application in industry. Carbon nanomaterials have excellent performance in optical properties, hardness, corrosion resistance, heat resistance, chemical resistance properties, radiation resistance properties, electrical insulation properties, electrical conductivity, surface and interface properties, etc. Secondary batteries, supercapacitors, sensors, catalyst carriers and other fields have a wide range of applications.

Porous carbon material is a carbon material with various pore structures. According to the regulations of the International Federation of Pure Applied Chemistry: pores with a diameter below 0.8nm are called submicropores, those between 0.8-2nm are called micropores, those between 2-50nm are called mesopores, and those greater than 50nm are called mesopores. for large holes. Therefore, according to the size of the pore size, porous materials can be divided into microporous materials, mesoporous materials, and macroporous materials. Methods for preparing mesoporous carbon materials include organogel carbonization, catalytic gasification and template methods. However, organogel carbonization and catalytic gasification are rarely used in the synthesis of mesoporous carbon materials because they cannot precisely control the pore structure, size, and pore size distribution. The template method has been widely used in the preparation of mesoporous carbon materials in recent years because it can precisely control the pore size and distribution, and can synthesize mesoporous carbon materials with regular pore structure.

Template method is divided into hard template method and soft template method. The hard template method refers to using a pre-prepared mesoporous silicon molecular sieve with a specific pore structure as a template, first filling the carbon precursor into the pores of the molecular sieve, and then removing the silicon template with sodium hydroxide or hydrofluoric acid to obtain Mesoporous carbon materials; the soft template method refers to the direct use of surfactants as structure-directing agents, which are combined with carbon precursors through the action of hydrogen bonds. , the carbon precursor becomes the skeleton of the pores after carbonization. Although the template method has the advantages of precisely controlling the pore size and pore distribution, it also has certain disadvantages. In the preparation of mesoporous carbon materials, the hard template method often needs to synthesize a hard template first, and then remove the template by etching. This method consumes a lot of hard templates and costs extremely high. In addition, the hard template method often has high requirements on carbon materials, such as better compatibility between the precursor and the hard template, and a mutually supporting structure between the pores to avoid the dislocation of the carbon material structure after the template is washed away. Compared with the hard template method, the soft template method does not require the participation of the silicon source and the removal of the silicon template, which avoids the cumbersome steps and waste of resources, but the soft template method generally requires an expensive block copolymer as a soft template. , the amount of template agent is high and the phase distribution required for mesoporous materials can be formed only under certain circumstances, which requires high preparation process. Therefore, it is very important to explore methods for facile preparation and accurate synthesis of mesoporous carbon materials.

As the most abundant natural renewable resource on earth, cellulose is the most widely distributed biopolymer in nature. Nanocellulose is a kind of nano-scale cellulose obtained by mechanical action or hydrolysis of natural cellulose, mainly including cellulose nanocrystals and cellulose nanofibers. Nanocellulose generally has a high aspect ratio, and its diameter distribution is generally 3-50 nm, which is in line with the diameter range of mesopores. In addition, the thermal degradation temperature of nanocellulose is generally lower than that of carbon materials, so it is very convenient to synthesize mesoporous carbon materials using nanocellulose as a template.

SUMMARY OF THE INVENTION

Aiming at the defects of the above-mentioned prior art, the present invention provides a method for preparing mesoporous carbon materials by using nanocellulose as a template. size and distribution, providing a new and facile method for the preparation of mesoporous carbon materials.

The technical scheme adopted in the present invention is as follows:

A method for preparing a mesoporous carbon material, comprising the following steps:

(1) preparation of phenolic resin precursor solution: mix phenol, formaldehyde solution and alkaline solution, raise the temperature to reaction temperature, react for a period of time, and then drop to room temperature to obtain phenolic resin precursor solution;

(2) Blending the precursor and the templating agent: blending the phenolic resin precursor solution obtained in step (1) with the templating agent, and ultrasonically treating it for a period of time;

(3) curing: the mixture obtained in step (2) is heated to the curing temperature, and cured for a period of time;

(4) carbonization: the solidified product obtained in step (3) is carbonized for a period of time by temperature-programmed heating under an inert gas atmosphere;

(5) post-treatment: pulverize the carbonized product obtained in step (4), clean, remove impurities, filter and dry to obtain mesoporous carbon material;

In the described step (1), the alkali solution is at least one of sodium hydroxide solution, potassium hydroxide solution, and ammonia; in the described phenol, formaldehyde solution and alkali solution, the mol ratio of phenol: formaldehyde: alkali is 1:0.5 ~3: 0.1 to 0.5; the reaction temperature is 50 to 100°C; the reaction time is 0.5 to 4 hours;

In the step (2), the templating agent is at least one of cellulose nanocrystals and cellulose nanofibers; the mass ratio of the phenolic resin precursor solution and the templating agent is 1:0.05-2, and the ultrasonic The time is 5 to 60 minutes;

In the step (3), the curing temperature is 120-180° C.; the reaction time is 5-60 minutes;

In the step (4), the inert gas is at least one of nitrogen gas and argon gas; the temperature program is to heat up to 300 to 400 ° C at a rate of 1 to 10 ° C/min, keep the temperature for 0.5 to 2 hours, and continue to use The temperature is raised to 600-900°C at a rate of 1-10°C/min, kept for 0.5-4 hours, and then naturally lowered to room temperature.

The significant advantages of the present invention are:

Compared with other preparation methods of mesoporous carbon materials, the operation method is simple and feasible, and the production cost is low, and the prepared mesoporous carbon material has controllable pore size and pore channels. Uniform and stable structure.

Detailed ways

The invention will be described in further detail below with reference to the examples, but the embodiments of the present invention are not limited thereto.

Example 1

(1) Preparation of phenolic resin precursor solution: 9.4 grams of phenol, 16.2 grams of formaldehyde solution and 2.8 grams of 20% potassium hydroxide solution were weighed and mixed, and heated in a constant temperature water bath at 70°C. The reaction time was 1 hour. to room temperature to obtain a phenolic resin precursor solution.

(2) Blending the precursor and the template agent: Weigh 4.75 g of the phenolic resin obtained in step (1) and 0.25 g of cellulose nanocrystals, mix, and ultrasonicate for 5 minutes.

(3) Curing: The product obtained in step (2) is heated to 150° C. and cured for 1 hour.

(4) carbonization: the solidified product obtained in step (3) is temperature-programmed and carbonized for a period of time under the atmosphere of nitrogen, and the temperature-programmed temperature is 3°C/min to be warmed to 300°C, maintained for 1 hour, and continued to heat up at 2°C/min to 700°C, incubated for 2 hours, and then cooled to room temperature naturally.

(5) Post-treatment: pulverizing, washing, removing impurities, filtering and drying the carbonized product obtained in step (4) to obtain a mesoporous carbon material.

Example 2

(1) Preparation of phenolic resin precursor solution: 9.4 grams of phenol, 11.9 grams of formaldehyde solution and 2.8 grams of 20% potassium hydroxide solution were weighed and mixed, heated in a constant temperature water bath at 70°C, the reaction time was 1 hour, and the reaction time was 1 hour. to room temperature to obtain a phenolic resin precursor solution.

(2) Blending the precursor and the template agent: Weigh 4.5 g of the phenolic resin obtained in step (1) and 0.5 g of cellulose nanocrystals, mix, and ultrasonicate for 15 minutes.

(3) Curing: The product obtained in step (2) is heated to 160° C. and cured for 1 hour.

(4) carbonization: the solidified product obtained in step (3) is temperature-programmed and carbonized for a period of time under the atmosphere of nitrogen, and the temperature-programmed temperature is 3°C/min to be warmed to 350°C, maintained for 1 hour, and continued to heat up at 2°C/min to 750°C, incubated for 2 hours, and then naturally cooled to room temperature.

(5) Post-treatment: pulverizing, washing, removing impurities, filtering and drying the carbonized product obtained in step (4) to obtain a mesoporous carbon material.

Example 3

(1) Preparation of phenolic resin precursor solution: Weigh 9.4 grams of phenol, 17.8 grams of formaldehyde solution and 2.8 grams of 20% potassium hydroxide solution, mix them, and heat them in a constant temperature water bath at 80°C. The reaction time is 0.5 hours. to room temperature to obtain a phenolic resin precursor solution.

(2) Blending the precursor and the template agent: Weigh 4 grams of the phenolic resin obtained in step (1) and 1 gram of cellulose nanocrystals and mix, and sonicate for 30 minutes.

(3) Curing: The product obtained in step (2) was heated to 170° C. and cured for 1 hour.

(4) carbonization: the solidified product obtained in step (3) is temperature-programmed and carbonized for a period of time under the atmosphere of nitrogen, and the temperature-programmed temperature is 5°C/min to be warmed to 400°C, maintained for 1.5 hours, and continued to heat up at 5°C/min to 800°C, incubated for 2 hours, and then cooled to room temperature naturally.

(5) Post-treatment: pulverizing, washing, removing impurities, filtering and drying the carbonized product obtained in step (4) to obtain a mesoporous carbon material.

Example 4

(1) Preparation of phenolic resin precursor solution: 9.4 grams of phenol, 16.2 grams of formaldehyde solution and 14 grams of 20% sodium hydroxide solution were weighed and mixed, and heated in a constant temperature water bath at 70°C. The reaction time was 1 hour. to room temperature to obtain a phenolic resin precursor solution.

(2) Blending the precursor and the template agent: Weigh 4.75 g of the phenolic resin and 0.25 g of the cellulose nanofibers obtained in step (1) and mix, and sonicate for 40 minutes.

(3) Curing: The product obtained in step (2) is heated to 150° C. and cured for 1 hour.

(4) carbonization: the solidified product obtained in step (3) is temperature-programmed and carbonized for a period of time under the atmosphere of nitrogen, and the temperature-programmed temperature is 3°C/min to be warmed to 350°C, maintained for 1 hour, and continued to heat up at 2°C/min to 700°C, incubated for 2 hours, and then cooled to room temperature naturally.

(5) Post-treatment: pulverizing, washing, removing impurities, filtering and drying the carbonized product obtained in step (4) to obtain a mesoporous carbon material.

Example 5

(1) Preparation of phenolic resin precursor solution: Weigh 9.4 grams of phenol, 16.2 grams of formaldehyde solution and 2.8 grams of ammonia solution and mix, heat in a constant temperature water bath at 70°C, and the reaction time is 1 hour, and it is lowered to room temperature to obtain phenolic Resin precursor solution.

(2) Blending of precursor and template agent: 4 grams of phenolic resin and 1 gram of cellulose nanofibers obtained in step (1) were weighed and mixed, and sonicated for 60 minutes.

(3) Curing: The product obtained in step (2) is heated to 150° C. and cured for 1 hour.

(4) carbonization: the solidified product obtained in step (3) is temperature-programmed and carbonized for a period of time under the atmosphere of nitrogen, and the temperature-programmed temperature is 3°C/min to be warmed to 350°C, maintained for 1 hour, and continued to heat up at 2°C/min to 700°C, incubated for 2 hours, and then cooled to room temperature naturally.

(5) Post-treatment: pulverizing, washing, removing impurities, filtering and drying the carbonized product obtained in step (4) to obtain a mesoporous carbon material.

Claims (1)

1. a preparation method of mesoporous carbon material, is characterized in that, comprises the following steps: (1) preparation of phenolic resin precursor solution: mix phenol, formaldehyde solution and alkaline solution, raise the temperature to reaction temperature, react for a period of time, and then drop to room temperature to obtain phenolic resin precursor solution; (2) Blending the precursor and the templating agent: blending the phenolic resin precursor solution obtained in step (1) with the templating agent, and ultrasonically treating it for a period of time; (3) curing: the mixture obtained in step (2) is heated to the curing temperature, and cured for a period of time; (4) carbonization: the solidified product obtained in step (3) is carbonized for a period of time by temperature-programmed heating under an inert gas atmosphere; (5) post-treatment: pulverize the carbonized product obtained in step (4), clean, remove impurities, filter and dry to obtain mesoporous carbon material; In the described step (1), the alkali solution is at least one of sodium hydroxide solution, potassium hydroxide solution, and ammonia; in the described phenol, formaldehyde solution and alkali solution, the mol ratio of phenol: formaldehyde: alkali is 1:0.5 ~3: 0.1 to 0.5; the reaction temperature is 50 to 100°C; the reaction time is 0.5 to 4 hours; In the step (2), the templating agent is at least one of cellulose nanocrystals and cellulose nanofibers; the mass ratio of the phenolic resin precursor solution and the templating agent is 1:0.05-0.25, and the ultrasonic The time is 5 to 60 minutes; In the step (3), the curing temperature is 120-180° C.; the reaction time is 5-60 minutes; In the step (4), the inert gas is at least one of nitrogen gas and argon gas; the temperature program is to heat up to 300 to 400 ° C at a rate of 1 to 10 ° C/min, keep the temperature for 0.5 to 2 hours, and continue to use The temperature is raised to 600-900°C at a rate of 1-10°C/min, kept for 0.5-4 hours, and then naturally lowered to room temperature.