Preparation method for obtaining graded porous carbon based on in-situ mesoporous generation technology
By introducing mesoporous structures during the synthesis of zeolite templates, hierarchical porous carbon was prepared using chemical vapor deposition, which solved the problem of mass transfer difficulties in ZTC materials. This enabled the orderly replication and complementary advantages of mesopores and micropores, resulting in a three-dimensional interconnected hierarchical pore structure.
Patent Information
- Application Number
- CN202511863920.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-11
- Publication Date
- 2026-02-10
AI Technical Summary
Existing ZTC materials face difficulties in mass transfer during liquid-phase or macromolecular applications. Current post-processing methods introduce mesopores but destroy the original microporous structure, failing to achieve the complementary advantages of micropores and mesopores.
By introducing mesoporous structures during the synthesis of zeolite templates, hierarchical porous carbon is prepared using chemical vapor deposition, avoiding the destruction of the carbon skeleton by post-processing and achieving the orderly replication of mesopores and micropores.
A three-dimensional interconnected hierarchical pore structure was fabricated, maintaining a high specific surface area and regular pores, thus solving the mass transfer bottleneck problem. The process is simple and easy to scale up.
Smart Images
Figure FT_1 
Figure FT_2 
Figure FT_3
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the field of porous carbon materials, and particularly relates to a preparation method of hierarchical porous carbon. The method is characterized in that: a zeolite template is subjected to a pre-pore treatment in a synthesis process, and then a method for synthesizing carbon material with hierarchical pore structure through CVD genetic synthesis is used. BACKGROUND
[0002] Zeolite-templated carbon (ZTC) is a new type of porous carbon material prepared by using microporous zeolite molecular sieve as a hard template, filling a carbon source precursor, carbonizing, and removing the template. Because it perfectly replicates the highly ordered microporous system of the zeolite template, ZTC exhibits extremely high specific surface area (usually > 3000 m 2 / g), regular pore structure, and narrow pore size distribution, which makes it have great application potential in the fields of adsorption, energy storage, catalysis, and the like. However, the pore structure of ZTC is almost completely dominated by micropores (pore size < 2 nm). This inherent structural characteristic leads to serious mass transfer limitations: in applications involving liquid phases or macromolecules, reactants and products are difficult to diffuse quickly; in electrochemical applications, the transmission resistance of electrolyte ions in the dense microporous network is extremely great. This makes it difficult for the material advantages of ZTC to be fully utilized in practical application scenarios with high power density or high mass transfer rate, and its performance potential is covered up by the huge diffusion resistance.
[0003] Although ZTC materials are widely used in various applications, among carbon materials, except for graphite and diamond, most of the others are random, complex-structure low-crystalline solids. Compared with crystalline materials, the lack of structural information hinders people's basic understanding of their behavior and performance in many applications. In order to overcome this problem, people have made great efforts to draw accurate real structure models on various carbon materials, and these real models play an extremely important role in solving unsolved problems and developing the chemical properties of carbon materials. In 2017, in order to understand the three-dimensional framework of zeolite-templated carbon in detail, researchers such as Hirotomo Nishihara constructed a real structure model of zeolite-templated carbon by computer simulation, and compared the simulated physical properties with experimental data (Carbon, 129 (2018) 854-862). The proposed structure model provides a unique x-ray diffraction pattern for ZTC: the disordered building units composed of curved and non-stacked graphene fragments are connected along the ordered zeolite nanochannels, forming long-range structural order derived from the (111) and (220) planes of zeolite.
[0004] To overcome the mass transfer bottleneck of ZTC, researchers have explored various post-processing methods to introduce mesopores, mainly physical activation methods (such as steam and CO2 activation) and chemical activation methods (such as KOH and ZnCl2 activation). However, these "post-modification" strategies all have inherent limitations: physical activation methods can introduce pores, but their pore size distribution is wide and the process is difficult to control precisely, and they are prone to carbon skeleton collapse and specific surface area loss due to excessive etching (Carbon, 46 (2008) 1718–1726); chemical activation methods have strong pore-forming ability, but are accompanied by serious equipment corrosion and environmental pollution problems, and their violent chemical reactions can also destroy the original regular microporous structure of ZTC (J. Hazard Mater. 161 (2009) 1384–1390). In essence, existing technologies are all secondary modifications based on the already established microporous ZTC. The contradiction lies in the fact that while introducing mesopores to improve mass transfer, it inevitably destroys the original highly ordered microporous framework and ultra-high specific surface area of ZTC, making it impossible to achieve the complementary advantages of micropores and mesopores.
[0005] Faced with the above problems, there is an urgent need for a novel strategy that can solve the mass transfer problem of ZTC at its source. The core idea of this invention is to advance the construction of the mesoporous structure to the template stage. By performing pre-mesoporization engineering on the zeolite template, and then utilizing the inherent "structural inheritance" characteristics in ZTC synthesis, the hierarchical porous structure is copied from the template to the final carbon material. Summary of the Invention
[0006] This invention proposes a method for preparing hierarchical porous carbon by in-situ generation of mesopores. The method is characterized by using a soft template agent to perform in-situ modification during template synthesis to form mesoporous channels, thereby obtaining a hierarchical porous zeolite template. Using the hierarchical porous zeolite template as a sacrificial template, a carbon source is introduced via chemical vapor deposition. After carbonization and template removal, a hierarchical porous carbon material is obtained.
[0007] The preparation method uses in-situ mesoporous molecular sieves (MEY) as templates and acetylene as a carbon source to synthesize hierarchical porous carbon. The MEY sample is placed in a CVD horizontal furnace, and the temperature is raised to 500 °C at a rate of 5 °C / min. Acetylene gas is then introduced into the furnace and held at this temperature for 270 min. The temperature is further increased to 850 °C and held for 2 h. Subsequently, the MEY framework is dissolved using a mixed acid of 0.3 M HF / 0.15 M HCl to obtain the final product.
[0008] The specific steps are as follows:
[0009] Step 1: First, dissolve 1 g NaOH in 16 g H2O, and slowly add 5 g colloidal silica under vigorous stirring, naming the mixture sol-A. Simultaneously, dissolve 1.14 g NaOH in 6 g H2O, and then add 0.52 g Al(OH)3. Name this mixture sol-B. After stirring sol-A and sol-B for 15 min, slowly add sol-B dropwise to sol-A, and stir in an ice bath (0-4 °C) for 1 h. Then add 1 g organosilane (DOAC) and stir for 2 h, then transfer to an oven for aging for 24 h. The aged gels are then subjected to hydrothermal treatment at 50 °C and 100 °C for 24 h, respectively. The resulting solids are washed with distilled water, dried, and then heated to 550 °C and held for 6 h to obtain hierarchical porous molecular sieves.
[0010] Step 2: Using hierarchical porous molecular sieves as templates and acetylene as a carbon precursor, 1 g of hierarchical porous molecular sieve was dissolved in 50 mL of 0.5 M CaCl2 solution and stirred under reflux at 80 °C for 3 h. The solution was then washed with distilled water and dried overnight. This process was repeated twice. The ion-exchanged hierarchical porous molecular sieve was placed in a crucible and pushed into a CVD horizontal furnace. A protective gas, N2, was introduced at a flow rate of 100 sccm. After purging the air from the tube, the temperature was raised to 500 °C at a rate of 5 °C / min, and then a mixture of acetylene (30 sccm) and nitrogen (70 sccm) was introduced for 270 min to perform the carbon deposition process. After precipitation, the acetylene was turned off, and heating was continued at 5 °C / min for 2 h to 850 °C to solidify the carbon structure. Finally, the mixture was allowed to cool naturally to room temperature.
[0011] Step 3: Dissolve the template mixed with carbon in 1 L of a mixed acid solution of 0.3M HF / 0.15M HCl, stir for 3 h, filter after etching, wash several times with distilled water during filtration to ensure that the mixed solution is completely removed, and dry in a vacuum oven at 60-70 ℃ for 12 h to finally obtain the product.
[0012] The beneficial effects of this invention are as follows: It employs a template prefabrication-structure inheritance strategy. By pre-constructing hierarchical channels in an inorganic template and perfectly replicating them in the carbon material during CVD, precise design and control of the ZTC pore structure are achieved from the source. The resulting carbon material perfectly inherits the regular microporous system of the zeolite template while replicating the pre-designed mesoporous network, forming a three-dimensional interconnected hierarchical pore structure. This method avoids post-processing damage to the carbon framework, is simple in process, has mild conditions, good reproducibility, and is easy to scale up for production, providing a universal solution to the mass transfer bottleneck problem of porous carbon materials. Attached Figure Description
[0013] The present invention will be further described below with reference to the accompanying drawings and embodiments.
[0014] Figure 1 This is the X-ray diffraction pattern of the hierarchical porous molecular sieve template prepared in Example 1;
[0015] Figure 2 This is the X-ray diffraction pattern of the hierarchical porous carbon prepared in Example 1;
[0016] Figure 3 These are transmission electron microscope images of the hierarchical porous molecular sieve template prepared in Example 1;
[0017] Figure 4 These are transmission electron microscope images of the hierarchical porous carbon prepared in Example 1;
[0018] Figure 5 These are scanning electron microscope images of the hierarchical porous molecular sieve template prepared in Example 1;
[0019] Figure 6 These are scanning electron microscope images of the hierarchical porous carbon prepared in Example 1;
[0020] Figure 7 These are the N2 adsorption-desorption curves and pore size distribution diagrams of the hierarchical porous molecular sieve template prepared in Example 1;
[0021] Figure 8 These are the N2 adsorption-desorption curves and pore size distribution diagrams of the hierarchical porous carbon prepared in Example 1;
[0022] Figure 9 This is a Raman image of the hierarchical porous carbon prepared in Example 1; Detailed Implementation
[0023] Example 1:
[0024] Step 1: First, dissolve 1 g of NaOH in 16 g of H2O, and slowly add 5 g of colloidal silica under vigorous stirring, naming the mixture sol-A. Simultaneously, dissolve 1.14 g of NaOH in 6 g of H2O, and then add 0.52 g of Al(OH)3. Name this mixture sol-B. After stirring sol-A and sol-B for 15 min, slowly add sol-B dropwise to sol-A, and stir in an ice bath (0-4 °C) for 1 h. Then add 1 g of organosilane (DOAC) and stir for 2 h, transferring to an oven for aging for 24 h. The aged gels are then subjected to hydrothermal treatment at 50 °C and 100 °C for 24 h, respectively. The resulting solids are washed with distilled water, dried, and then heated to 550 °C and held for 6 h to obtain a hierarchical porous molecular sieve.
[0025] Step 2: Using hierarchical porous molecular sieves as templates and acetylene as a carbon precursor, 1 g of hierarchical porous molecular sieve was dissolved in 50 mL of 0.5 M CaCl2 solution and stirred under reflux at 80 °C for 3 h. The solution was then washed with distilled water and dried overnight. This process was repeated twice. The ion-exchanged hierarchical porous molecular sieve was placed in a crucible and pushed into a CVD horizontal furnace. A protective gas, N2, was introduced at a flow rate of 100 sccm. After purging the air from the tube, the temperature was raised to 500 °C at a rate of 5 °C / min, and then a mixture of acetylene (30 sccm) and nitrogen (70 sccm) was introduced for 270 min to perform the carbon deposition process. After precipitation, the acetylene was turned off, and heating was continued at 5 °C / min to 850 °C for 2 h to solidify the carbon structure. Finally, the mixture was allowed to cool naturally to room temperature.
[0026] Step 3: Dissolve the template mixed with carbon in 1 L of a mixed acid solution of 0.3M HF / 0.15M HCl, stir for 3 h, filter after etching, wash several times with distilled water during the filtration process to ensure that the mixed solution is completely removed, and dry in a vacuum oven at 60-70 °C for 12 h to finally obtain the product.
[0027] Example 2:
[0028] Step 1: First, dissolve 1 g NaOH in 16 g H2O, and slowly add 5 g colloidal silica under vigorous stirring, naming the mixture sol-A. Simultaneously, dissolve 1.14 g NaOH in 6 g H2O, and then add 0.52 g Al(OH)3. Name this mixture sol-B. After stirring sol-A and sol-B for 15 min, slowly add sol-B dropwise to sol-A, stir in an ice bath (0-4 °C) for 1 h, and then transfer to an oven for aging for 24 h. The aged gels are then subjected to hydrothermal treatment at 50 °C and 100 °C for 24 h, respectively. The resulting solids are washed with distilled water, dried, and then heated to 550 °C and held for 6 h to obtain a hierarchical porous molecular sieve.
[0029] Step 2: Using the obtained molecular sieve as a template and acetylene as a carbon precursor, 1 g of the obtained molecular sieve was dissolved in 50 mL of 0.5 M CaCl2 solution and stirred under reflux at 80 °C for 3 h. The solution was then washed with distilled water and dried overnight. This process was repeated twice. The ion-exchanged molecular sieve was placed in a crucible and pushed into a CVD horizontal furnace. A protective gas, N2, was introduced at a flow rate of 100 sccm. After purging the air from the tube, the temperature was raised to 500 °C at a rate of 5 °C / min, and then a mixture of acetylene (30 sccm) and nitrogen (70 sccm) was introduced for 270 min to carry out the carbon deposition process. After precipitation, the acetylene was turned off, and heating was continued at 5 °C / min to 850 °C for 2 h to solidify the carbon structure. Finally, the mixture was allowed to cool naturally to room temperature.
[0030] Step 3: Dissolve the template mixed with carbon in 1 L of a mixed acid solution of 0.3M HF / 0.15M HCl, stir for 3 h, filter after etching, wash several times with distilled water during the filtration process to ensure that the mixed solution is completely removed, and dry in a vacuum oven at 60-70 °C for 12 h to finally obtain the product.
[0031] Example 3:
[0032] Step 1: First, dissolve 1 g NaOH in 16 g H2O, and slowly add 5 g colloidal silica under vigorous stirring, naming the mixture sol-A. Simultaneously, dissolve 1.14 g NaOH in 6 g H2O, and then add 0.52 g Al(OH)3. Name this mixture sol-B. After stirring sol-A and sol-B for 15 min, slowly add sol-B dropwise to sol-A, and stir in an ice bath (0-4 °C) for 1 h. Then add 1 g organosilane (DOAC) and stir for 2 h, transferring to an oven for aging for 24 h. The aged gels are then subjected to hydrothermal treatment at 50 °C and 100 °C for 24 h, respectively. The resulting solids are washed with distilled water, dried, and then heated to 550 °C and held for 6 h to obtain a hierarchical porous molecular sieve.
[0033] Step 2: Using hierarchical porous molecular sieves as templates and acetylene as a carbon precursor, 1 g of hierarchical porous molecular sieve was dissolved in 50 mL of 0.5 M CaCl2 solution and stirred under reflux at 80°C for 3 h. The solution was then washed with distilled water and dried overnight. This process was repeated twice. The ion-exchanged hierarchical porous molecular sieve was placed in a crucible and pushed into a CVD horizontal furnace. A protective gas, N2, was introduced at a flow rate of 100 sccm. After purging the air from the tube, the temperature was raised to 400 °C at a rate of 5 °C / min, and then a mixture of acetylene (30 sccm) and nitrogen (70 sccm) was introduced for 270 min to carry out the carbon deposition process. After precipitation, the acetylene was turned off, and heating was continued at 5 °C / min to 850 °C for 2 h to solidify the carbon structure. Finally, the mixture was allowed to cool naturally to room temperature.
[0034] Step 3: Dissolve the template mixed with carbon in 1 L of a mixed acid solution of 0.3M HF / 0.15M HCl, stir for 3 h, filter after etching, wash several times with distilled water during the filtration process to ensure that the mixed solution is completely removed, and dry in a vacuum oven at 60-70 °C for 12 h to finally obtain the product.
[0035] Example 4:
[0036] Step 1: First, dissolve 1 g NaOH in 16 g H2O, and slowly add 5 g colloidal silica under vigorous stirring, naming the mixture sol-A. Simultaneously, dissolve 1.14 g NaOH in 6 g H2O, and then add 0.52 g Al(OH)3. Name this mixture sol-B. After stirring sol-A and sol-B for 15 min, slowly add sol-B dropwise to sol-A, and stir in an ice bath (0-4 °C) for 1 h. Then add 1 g organosilane (DOAC) and stir for 2 h, then transfer to an oven for aging for 24 h. The aged gels are then subjected to hydrothermal treatment at 50 °C and 100 °C for 24 h, respectively. The resulting solids are washed with distilled water, dried, and then heated to 550 °C and held for 6 h to obtain hierarchical porous molecular sieves.
[0037] Step 2: Using hierarchical porous molecular sieves as templates and acetylene as a carbon precursor, 1 g of hierarchical porous molecular sieve was dissolved in 50 mL of 0.5 M CaCl2 solution and stirred under reflux at 80 °C for 3 h. The solution was then washed with distilled water and dried overnight. This process was repeated twice. The ion-exchanged hierarchical porous molecular sieve was placed in a crucible and pushed into a CVD horizontal furnace. A protective gas, N2, was introduced at a flow rate of 100 sccm. After purging the air from the tube, the temperature was raised to 500 °C at a rate of 5 °C / min, and then a mixture of acetylene (20 sccm) and nitrogen (80 sccm) was introduced for 270 min to perform the carbon deposition process. After precipitation, the acetylene was turned off, and heating was continued at 5 °C / min for 2 h to 850 °C to solidify the carbon structure. Finally, the mixture was allowed to cool naturally to room temperature.
[0038] Step 3: Dissolve the template mixed with carbon in 1 L of a mixed acid solution of 0.3M HF / 0.15M HCl, stir for 3 h, filter after etching, wash several times with distilled water during the filtration process to ensure that the mixed solution is completely removed, and dry in a vacuum oven at 60-70 °C for 12 h to finally obtain the product.
[0039] The above description is merely a preferred embodiment of the present invention and should not be construed as limiting the scope of protection of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall fall within the scope of the technical solution of the present invention.
Claims
1. A method for preparing hierarchical porous carbon based on in-situ mesoporous generation technology, characterized in that... A soft template agent was used to modify the template in situ during the template synthesis process to form mesoporous channels, thus obtaining a hierarchical porous zeolite template. Using the hierarchical porous zeolite template as a sacrificial template, a carbon source is introduced by chemical vapor deposition. After carbonization and template removal, a hierarchical porous carbon material is obtained. The method for preparing hierarchical porous carbon is characterized by comprising the following specific steps: Step 1: First, dissolve 1 g NaOH in 16 g H2O, and slowly add 5 g colloidal silica under vigorous stirring, naming the mixture sol-A; simultaneously, dissolve 1.14 g NaOH in 6 g H2O, and then add 0.52 g Al(OH)3, naming the mixture sol-B; after stirring sol-A and sol-B for 15 min, slowly add sol-B dropwise to sol-A, and stir in an ice bath (0-4 °C) for 1 h; then add 1 g organosilane (DOAC) and stir for 2 h, and transfer to an oven for aging for 24 h; the aged gel is subjected to hydrothermal treatment at 50 °C and 100 °C for 24 h respectively; the resulting solid is washed with distilled water, dried, and then heated to 550 °C and held for 6 h to obtain a hierarchical porous molecular sieve; Step 2: Using hierarchical porous molecular sieve as a template and acetylene as a carbon precursor, 1 g of hierarchical porous molecular sieve was dissolved in 50 mL of 0.5 M CaCl2 solution, stirred and refluxed at 80 °C for 3 h, washed with distilled water and dried overnight. This process was repeated twice. The ion-exchanged hierarchical porous molecular sieve was placed in a crucible and pushed into a CVD horizontal furnace; protective gas N2 was introduced at a flow rate of 100 sccm; after purging the air in the tube, the temperature was raised to 500 °C at a rate of 5 °C / min, and then a mixture of acetylene (30 sccm) and nitrogen (70 sccm) was introduced for 270 min to carry out the carbon deposition process; after precipitation, the acetylene was turned off, and the temperature was continued to be raised to 850 °C at a rate of 5 °C / min and held for 2 h to solidify the carbon structure; finally, it was allowed to cool naturally to room temperature. Step 3: Dissolve the template mixed with carbon in 1 L of a mixed acid solution of 0.3M HF / 0.15M HCl, stir for 3 h, filter after etching, wash several times with distilled water during the filtration process to ensure that the mixed solution is completely removed, and dry in a vacuum oven at 60-70 ℃ for 12 h to finally obtain the product.
2. The preparation method according to claim 1, characterized in that, In step one, the soft template agent is a dimethyloctadecyl[3-trimethoxysilylpropyl]ammonium chloride solution.
3. The preparation method according to claim 1, characterized in that, In step two, the heating rate is 5 °C / min, and the reaction temperature is 400-500 °C.
4. The preparation method according to claim 1, characterized in that, In step two, the volume fraction of acetylene gas is 20-30%.