Monodisperse cyclodextrin-derived carbon nanospheres and preparation method thereof
By controlling the ratio of cyclodextrin, surfactant, and electrolyte through hydrothermal carbonization, monodisperse cyclodextrin-derived carbon nanospheres were prepared, solving the problems of high energy consumption and agglomeration in existing methods. This achieved the preparation of low-cost, highly monodisperse carbon nanospheres, broadening their application in the field of electrochemistry.
Patent Information
- Application Number
- CN202511670892.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-14
- Publication Date
- 2026-01-16
AI Technical Summary
Existing methods for preparing carbon nanospheres involve high temperature and high energy consumption, complex equipment, and high cost. Furthermore, it is difficult to obtain products with good monodispersity, which affects their performance in fields such as electrode materials and catalyst supports.
Monodisperse cyclodextrin-derived carbon nanospheres were prepared by hydrothermal carbonization, controlling the ratio of cyclodextrin, surfactant, and water, and combining electrolyte and nitrogen dopant. The nucleation and growth of the carbon nanospheres were controlled by utilizing the guiding and steric stabilizing effects of the surfactant.
Carbon nanospheres with uniform size and good monodispersity were successfully prepared. The process is simple and the conditions are mild, making it suitable for large-scale production. Furthermore, the electronic structure of the material can be adjusted by nitrogen doping, thus broadening its application range.
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Figure CN121342003A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the technical field of materials, and particularly relates to a monodisperse cyclodextrin-derived carbon nanosphere and a preparation method thereof. BACKGROUND
[0002] As an important carbon nanomaterial, carbon nanospheres have great application potential in the fields of energy storage (such as lithium ion batteries and supercapacitors), adsorption separation, catalytic carriers and biomedicine due to their large specific surface area, good chemical stability, excellent electrical conductivity and controllable structure.
[0003] At present, common methods for preparing carbon nanospheres include chemical vapor deposition, arc method and template method. However, these methods usually have some limitations, for example: the chemical vapor deposition and arc method often require high-temperature and high-energy consumption reaction conditions, and the equipment is complex and the cost is high; although the template method can accurately control the size, the subsequent template removal step is cumbersome, which may damage the structure of the spheres and cause environmental burden.
[0004] In addition, the carbon nanospheres prepared by the above methods are prone to agglomeration, and it is difficult to obtain monodisperse (i.e. uniform size and non-agglomeration) products. Monodispersity is crucial for the performance of carbon nanospheres in practical applications, for example, when used as electrode materials, monodisperse spheres are beneficial to the formation of a uniform conductive network, improving performance; when used as catalyst carriers, monodispersity helps to uniformly distribute active sites.
[0005] Therefore, it is a technical problem to be solved in the field to develop a method for preparing monodisperse carbon nanospheres in batches with simple process, mild conditions and low cost.
[0006] Therefore, the present application is proposed. SUMMARY
[0007] The present application aims to provide a monodisperse cyclodextrin-derived carbon nanosphere and a preparation method thereof to solve the above problems.
[0008] To achieve the above purpose, the present application adopts the following technical solutions: A preparation method of a monodisperse cyclodextrin-derived carbon nanosphere, comprising: mixing cyclodextrin, a surfactant and water, and performing a hydrothermal carbonization reaction; After the hydrothermal carbonization reaction is completed, the mixture is cooled, centrifuged, and an electrolyte is added during the centrifugation process, and then the solid product is washed, collected and dried to obtain the monodisperse cyclodextrin-derived carbon nanosphere.
[0009] Preferably, the preparation method of the monodisperse cyclodextrin-derived carbon nanosphere satisfies one or more of the following conditions: (1) the cyclodextrin includes any one or more of a-cyclodextrin, b-cyclodextrin, g-cyclodextrin; (2) the surfactant includes one or more of polyelectrolyte, non-ionic surfactant.
[0010] Preferably, the surfactant includes one or more of polyether F127, polyether P123, sodium polyacrylate, cetyltrimethylammonium chloride (CTAC), polydiallyldimethylammonium chloride (PDDA).
[0011] Preferably, the preparation method of the monodisperse cyclodextrin-derived carbon nanospheres meets one or more of the following conditions: (1) the temperature of the hydrothermal carbonization reaction is 180-250℃, and the time is 1-24h; (2) the rotation speed of the centrifugal separation is 6000-15000rpm, preferably 8000-12000rpm; (3) the mass ratio of the cyclodextrin, surfactant and water is (0.015~0.5):(0.0001~0.05):1.
[0012] Preferably, a nitrogen dopant is added to the reaction system before the hydrothermal carbonization reaction.
[0013] Preferably, the nitrogen dopant is a compound containing an amino functional group; Preferably, the nitrogen dopant includes one or more of urea, melamine, dicyandiamide, thiourea.
[0014] Preferably, the mass ratio of the dopant to cyclodextrin is (0~0.2):1.
[0015] Preferably, the electrolyte is an alkaline aqueous solution; Preferably, the alkaline electrolyte is an aqueous solution of one or more of sodium hydroxide, potassium hydroxide or ammonia.
[0016] The electrolyte is an alkaline aqueous solution, which is used to neutralize the surface charge of the colloidal particles to achieve their destabilization and coagulation.
[0017] Preferably, the washing includes: Repeated washing with anhydrous ethanol and deionized water until the supernatant is clear.
[0018] The application also provides a monodisperse cyclodextrin-derived carbon nanosphere prepared by the preparation method of the monodisperse cyclodextrin-derived carbon nanosphere.
[0019] The application has the following advantages: The monodisperse cyclodextrin-derived carbon nanosphere and the preparation method thereof provided by the application have the following advantages: 1. Good monodispersity: the present application successfully prepares carbon nanospheres with uniform size and good monodispersity by precisely regulating the ratio of raw materials cyclodextrin, surfactant and water, and effectively controlling the nucleation and growth of carbon nanospheres in the hydrothermal process by the guidance and space stabilization of surfactant, overcoming the defect of easy agglomeration of products in traditional methods.
[0020] 2. Simple process and mild conditions: the present application takes hydrothermal carbonization as the core technology, and the reaction is carried out in liquid phase, which is significantly lower in temperature than chemical vapor deposition method, etc., and has low equipment requirements, small energy consumption, simple operation and environmental friendliness, and is very suitable for large-scale production.
[0021] 3. Functional modification: by introducing nitrogen dopant in the reaction system, uniform doping of nitrogen element can be realized at the same time of forming carbon nanospheres, so as to adjust the electronic structure and surface chemical properties of the material, and broaden its application in the field of electrochemistry, etc.
[0022] 4. Wide application prospect: the monodisperse carbon nanospheres prepared by the present application have the advantages of regular structure, adjustable specific surface area and controllable surface properties, and have important application value in high-performance supercapacitor electrode materials, lithium ion battery negative electrode materials, high-efficiency adsorbents and noble metal catalyst carriers, etc. BRIEF DESCRIPTION OF DRAWINGS
[0023] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the description of the specific embodiments or the prior art. Obviously, the drawings described below are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of these drawings.
[0024] Figure 1 is a scanning electron microscope photograph of the monodisperse cyclodextrin-derived carbon nanospheres prepared in Example 1; Figure 2 is a graph of the average particle size distribution of the monodisperse cyclodextrin-derived carbon nanospheres prepared in Example 1; Figure 3 is a graph of the XPS test results of the monodisperse cyclodextrin-derived carbon nanospheres prepared in Example 4; Figure 4 is a scanning electron microscope photograph of the carbon nanospheres prepared in Comparative Example 1; Figure 5 is a scanning electron microscope photograph of the carbon nanospheres prepared in Comparative Example 2. DETAILED DESCRIPTION
[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and 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.
[0026] Example 1 This embodiment provides a method for preparing monodisperse cyclodextrin-derived carbon nanospheres, including the following steps: 1) Mix β-cyclodextrin, polydimethylammonium chloride, and deionized water in a mass ratio of 0.08:0.003:1 at 60°C with magnetic stirring to form a uniform and transparent solution.
[0027] 2) Transfer the above solution to a 100ml stainless steel hydrothermal reactor lined with polytetrafluoroethylene. The volume of the solution is about 60% of the reactor volume. Place the reactor in an oven and react at 200°C for 12 hours.
[0028] 3) After the reaction is complete, allow it to cool naturally to room temperature. Open the reaction vessel and transfer the resulting black suspension to a centrifuge tube. During centrifugation, add 3 mol / L NaOH aqueous solution dropwise until obvious flocculation is observed.
[0029] 4) Centrifuge at 9000 rpm for 10 minutes, discard the supernatant, and collect the precipitate. Wash the precipitate three times each with anhydrous ethanol and deionized water, alternating between the two, until the supernatant becomes clear.
[0030] 5) The washed solid product was placed in a vacuum drying oven at 80°C and dried for 12 hours to obtain monodisperse cyclodextrin-derived carbon nanosphere powder.
[0031] The cyclodextrin-derived carbon nanospheres prepared in this embodiment have an average particle size of approximately 62.0 nm, as shown in the scanning electron microscope (SEM) image. Figure 1 As shown, the particle size distribution is as follows: Figure 2 As shown, the spherical morphology is good, it has good monodispersity, and the yield is as high as 44.8%.
[0032] Example 2 This embodiment provides a method for preparing monodisperse cyclodextrin-derived carbon nanospheres, including the following steps: 1) Mix β-cyclodextrin, polydimethylammonium chloride, polyether F127, and deionized water in a mass ratio of 0.08:0.003:0.004:1 with magnetic stirring at 60°C to form a uniform and transparent solution.
[0033] 2) Transfer the above solution to a 100ml stainless steel hydrothermal reactor lined with polytetrafluoroethylene. The volume of the solution is about 60% of the reactor volume. Place the reactor in an oven and react at 200°C for 12 hours.
[0034] 3) After the reaction is complete, allow it to cool naturally to room temperature. Open the reaction vessel and transfer the resulting black suspension to a centrifuge tube. During centrifugation, add 25% ammonia solution dropwise until obvious flocculation is observed.
[0035] 4) Centrifuge at 9000 rpm for 10 minutes, discard the supernatant, and collect the precipitate. Wash the precipitate three times each with anhydrous ethanol and deionized water, alternating between the two, until the supernatant becomes clear.
[0036] 5) The washed solid product was placed in a vacuum drying oven at 80°C and dried for 12 hours to obtain monodisperse cyclodextrin-derived carbon nanosphere powder.
[0037] The cyclodextrin-derived carbon nanospheres prepared in this embodiment have an average particle size of about 61.0 nm, good spherical morphology and monodispersity, and the yield decreased to 40.2%.
[0038] Example 3 This embodiment provides a method for preparing monodisperse cyclodextrin-derived carbon nanospheres, including the following steps: 1) Mix β-cyclodextrin, polydimethylammonium chloride, polyether F127, and deionized water in a mass ratio of 0.08:0.003:0.008:1 with magnetic stirring at 60°C to form a uniform and transparent solution.
[0039] 2) Transfer the above solution to a 100ml stainless steel hydrothermal reactor lined with polytetrafluoroethylene. The volume of the solution is about 60% of the reactor volume. Place the reactor in an oven and react at 200°C for 12 hours.
[0040] 3) After the reaction is complete, allow it to cool naturally to room temperature. Open the reaction vessel and transfer the resulting black suspension to a centrifuge tube. During centrifugation, add 3 mol / L NaOH aqueous solution dropwise until obvious flocculation is observed.
[0041] 4) Centrifuge at 9000 rpm for 10 minutes, discard the supernatant, and collect the precipitate. Wash the precipitate three times each with anhydrous ethanol and deionized water, alternating between the two, until the supernatant becomes clear.
[0042] 5) The washed solid product was placed in a vacuum drying oven at 80°C and dried for 12 hours to obtain monodisperse cyclodextrin-derived carbon nanosphere powder.
[0043] The cyclodextrin-derived carbon nanospheres prepared in this embodiment have an average particle size of about 60.1 nm, good spherical morphology and monodispersity, and the yield decreased to 38.9%.
[0044] Example 4 This embodiment provides a method for preparing nitrogen-doped monodisperse cyclodextrin-derived carbon nanospheres, including the following steps: 1) Mix β-cyclodextrin, polydimethylammonium chloride, melamine, and deionized water in a mass ratio of 0.08:0.003:0.0017:1 with magnetic stirring at 60°C to form a uniform and transparent solution.
[0045] 2) Transfer the above solution to a 100ml stainless steel hydrothermal reactor lined with polytetrafluoroethylene. The volume of the solution is about 60% of the reactor volume. Place the reactor in an oven and react at 200°C for 12 hours.
[0046] 3) After the reaction is complete, allow it to cool naturally to room temperature. Open the reaction vessel and transfer the resulting black suspension to a centrifuge tube. During centrifugation, add 3 mol / L NaOH aqueous solution dropwise until obvious flocculation is observed.
[0047] 4) Centrifuge at 9000 rpm for 10 minutes, discard the supernatant, and collect the precipitate. Wash the precipitate three times each with anhydrous ethanol and deionized water, alternating between the two, until the supernatant becomes clear.
[0048] 5) The washed solid product was placed in a vacuum drying oven at 80°C and dried for 12 hours to obtain monodisperse cyclodextrin-derived carbon nanosphere powder.
[0049] The cyclodextrin-derived carbon nanospheres prepared in this embodiment have an average particle size of approximately 78 nm, exhibiting good spherical morphology and monodispersity, and a high yield of 50.6%. X-ray photoelectron spectroscopy (XPS) analysis of the sample from Example 4 revealed a nitrogen content of 7.46%, confirming the introduction of nitrogen. Figure 3 The figure shows the fine spectral fitting curves for nitrogen, revealing that nitrogen exists primarily in the forms of pyridine nitrogen, pyrrole nitrogen, and graphitic nitrogen. These nitrogen species, especially pyridine nitrogen and graphitic nitrogen, can donate lone pairs of electrons to the π-system of the carbon matrix, significantly enhancing the electronic conductivity of carbon materials and providing abundant surface active sites.
[0050] Comparative Example 1 This comparative example provides a method for preparing carbon nanospheres, including the following steps: 1) Mix β-cyclodextrin, polydimethylammonium chloride, and deionized water in a mass ratio of 0.08:0.0008:1 at 60°C with magnetic stirring to form a uniform and transparent solution.
[0051] 2) Transfer the above solution to a 100ml stainless steel hydrothermal reactor lined with polytetrafluoroethylene. The volume of the solution is about 60% of the reactor volume. Place the reactor in an oven and react at 200°C for 12 hours.
[0052] 3) After the reaction is complete, allow it to cool naturally to room temperature. Open the reaction vessel, transfer the resulting black suspension to a centrifuge tube, centrifuge at 9000 rpm for 10 minutes, discard the supernatant, and collect the precipitate. Wash the precipitate three times each with anhydrous ethanol and deionized water, alternating between the two, until the supernatant becomes clear.
[0053] 4) Place the washed solid product in an 80℃ vacuum drying oven and dry for 12 hours to obtain cyclodextrin-derived carbon nanosphere powder.
[0054] The difference between this comparative example and Example 1 is that a small amount of PDDA was added. The scanning electron microscope (SEM) image of the product obtained in Comparative Example 1 is shown below. Figure 4 As shown, the resulting product is a heavily aggregated carbon nanosphere, which cannot form a monodisperse nanosphere structure. This indicates that surfactants are crucial for the formation of monodisperse carbon nanospheres.
[0055] Comparative Example 2 This comparative example provides a method for preparing carbon nanospheres, including the following steps: 1) Mix β-cyclodextrin, polydimethylammonium chloride, melamine, and deionized water in a mass ratio of 0.08:0.003:0.02:1 with magnetic stirring at 60°C to form a uniform and transparent solution.
[0056] 2) Transfer the above solution to a 100ml stainless steel hydrothermal reactor lined with polytetrafluoroethylene. The volume of the solution is about 60% of the reactor volume. Place the reactor in an oven and react at 200°C for 12 hours.
[0057] 3) After the reaction is complete, allow it to cool naturally to room temperature. Open the reaction vessel and transfer the resulting black suspension to a centrifuge tube. During centrifugation, add 3 mol / L NaOH aqueous solution dropwise until obvious flocculation is observed.
[0058] 4) Centrifuge at 9000 rpm for 10 minutes, discard the supernatant, and collect the precipitate. Wash the precipitate three times each with anhydrous ethanol and deionized water, alternating between the two, until the supernatant becomes clear.
[0059] 5) Place the washed solid product in an 80℃ vacuum drying oven and dry for 12 hours to obtain cyclodextrin-derived carbon nanosphere powder.
[0060] The difference between this comparative example and Example 4 is that a large amount of melamine was added. The scanning electron microscope (SEM) image of the product obtained in Comparative Example 2 is shown below. Figure 5 As shown, the obtained product is severely agglomerated and cannot form a monodisperse nanosphere structure. This indicates that the excessive increase in the amount of dopant and the excessive degree of cross-linking of the material lead to poor sphericity and dispersibility of carbon nanospheres.
[0061] Comparative Example 3 This comparative example provides a method for preparing carbon nanospheres, including the following steps: 1) Mix β-cyclodextrin, polydimethylammonium chloride, polyether F127, and deionized water in a mass ratio of 0.08:0.003:0.004:1 with magnetic stirring at 60°C to form a uniform and transparent solution.
[0062] 2) Transfer the above solution to a 100ml stainless steel hydrothermal reactor lined with polytetrafluoroethylene. The volume of the solution is about 60% of the reactor volume. Place the reactor in an oven and react at 200°C for 12 hours.
[0063] 3) After the reaction is complete, allow it to cool naturally to room temperature. Open the reaction vessel, transfer the resulting black suspension to a centrifuge tube, centrifuge at 9000 rpm for 10 minutes, discard the supernatant, and collect the precipitate. Wash the precipitate three times each with anhydrous ethanol and deionized water, alternating between the two, until the supernatant becomes clear.
[0064] 4) Place the washed solid product in an 80℃ vacuum drying oven and dry for 12 hours to obtain cyclodextrin-derived carbon nanosphere powder.
[0065] The difference between this comparative example and Example 2 is that no electrolyte was added during the separation process. The result was that it was almost impossible to obtain a solid product by centrifugation. This is because the generated carbon nanosphere colloids have extremely small particle sizes and surface charges. These two factors combined give the colloidal system high kinetic and electrostatic stability, making effective sedimentation difficult to achieve by centrifugation.
[0066] Comparative Example 4 This comparative example provides a method for preparing carbon nanospheres, including the following steps: 1) Mix β-cyclodextrin, polydimethylammonium chloride, and deionized water in a mass ratio of 0.08:0.003:1 at 60°C with magnetic stirring to form a uniform and transparent solution.
[0067] 2) Transfer the above solution to a 100ml stainless steel hydrothermal reactor lined with polytetrafluoroethylene. The volume of the solution is about 60% of the reactor volume. Place the reactor in an oven and react at 170°C for 12 hours.
[0068] 3) After the reaction is complete, allow it to cool naturally to room temperature. Open the reaction vessel and transfer the resulting black suspension to a centrifuge tube. During centrifugation, add approximately 9 ml of a 25% ammonia solution dropwise. No obvious sedimentation was observed.
[0069] 4) Centrifuge at 9000 rpm for 10 minutes, discard the supernatant, and collect the precipitate. Wash the precipitate three times each with anhydrous ethanol and deionized water, alternating between the two, until the supernatant becomes clear.
[0070] 5) The washed solid product was placed in a vacuum drying oven at 80°C and dried for 12 hours to obtain monodisperse cyclodextrin-derived carbon nanosphere powder.
[0071] The difference between this comparative example and Example 2 is that the reaction temperature is different, and the amount of solid product collected by centrifugation is significantly lower than that in Example 2, with a yield of only 5%.
[0072] Results Analysis: At the relatively low temperature of 170℃, the thermodynamic energy provided by the reaction system was insufficient to drive the precursor to fully complete the crucial steps of aromatization and cross-linking polycondensation, which form a three-dimensional stable carbonaceous framework. Therefore, the reaction system contained a large amount of intermediate products or oligomers that were not converted into insoluble solid carbon. These substances were removed from the supernatant during subsequent centrifugation, resulting in a significantly reduced yield of the final collected solids.
[0073] Please note that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. The above embodiments only illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.
Claims
1. A method for preparing monodisperse cyclodextrin derivative carbon nanospheres, characterized in that, Comprising: mixing cyclodextrin, surfactant and water, and carrying out hydrothermal carbonization reaction; after the hydrothermal carbonization reaction, cooling the mixture, centrifugal separation, adding electrolyte during the centrifugal separation, washing, collecting solid product, and drying to obtain the monodisperse cyclodextrin derivative carbon nanospheres.
2. The method for preparing monodisperse cyclodextrin-derived carbon nanospheres according to claim 1, characterized in that, One or more of the following conditions are met: (1) the cyclodextrin includes any one or more of α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin; (2) the surfactant includes one or more of polyelectrolyte and non-ionic surfactant.
3. The method for preparing monodisperse cyclodextrin-derived carbon nanospheres according to claim 2, characterized in that, The surfactant includes one or more of polyether F127, polyether P123, sodium polyacrylate, cetyltrimethylammonium chloride, and polydiallyldimethylammonium chloride.
4. The method for preparing monodisperse cyclodextrin-derived carbon nanospheres according to claim 1, characterized in that, One or more of the following conditions are met: (1) the temperature of the hydrothermal carbonization reaction is 180-250℃, and the time is 1-24h; (2) the centrifugal separation speed is 6000-15000rpm, preferably 8000-12000rpm; (3) the mass ratio of the cyclodextrin, surfactant, and water is (0.015~0.5) : (0.0001~0.05) :
1.
5. The method for preparing monodisperse cyclodextrin-derived carbon nanospheres according to claim 1, characterized in that, Before the hydrothermal carbonization reaction, a nitrogen dopant is added to the reaction system.
6. The method for preparing monodisperse cyclodextrin-derived carbon nanospheres according to claim 5, characterized in that, The nitrogen dopant is a compound containing an amino functional group; Preferably, the nitrogen dopant includes one or more of urea, melamine, dicyandiamide, and thiourea.
7. The method for preparing monodisperse cyclodextrin-derived carbon nanospheres according to claim 6, characterized in that, The mass ratio of the dopant to cyclodextrin is (0~0.2) :
1.
8. The method for preparing monodisperse cyclodextrin-derived carbon nanospheres according to claim 1, characterized in that, The electrolyte is an alkaline aqueous solution; Preferably, the alkaline electrolyte is an aqueous solution of one or more of sodium hydroxide, potassium hydroxide, or ammonia.
9. The method for preparing monodisperse cyclodextrin-derived carbon nanospheres according to any one of claims 1-8, characterized in that, The washing includes: repeated washing with anhydrous ethanol and deionized water until the supernatant is clear.
10. A monodisperse cyclodextrin derivative carbon nanosphere, characterized in that, The monodisperse cyclodextrin derivative carbon nanospheres are prepared using the preparation method of any one of claims 1-9.