Resin-based carbon material microspheres, preparation method therefor, and use thereof

Abstract

Resin-based carbon material microspheres, a preparation method therefor, and the use thereof, belonging to the field of carbon materials. The preparation method comprises the following steps: (1) mixing an alcohol-soluble phenolic resin with ethanol and water to obtain a resin dispersion liquid, the volume fraction of ethanol in the resin dispersion liquid being 30-80%, and the concentration of the resin dispersion liquid being 0.01-0.10 g / ml; (2) freeze-drying the resin dispersion liquid to obtain resin microspheres; and (3) carbonizing the resin microspheres in a protective atmosphere to obtain the carbon material microspheres. The preparation process involves a simple route and low raw material cost and thus facilitates mass production. The prepared carbon material microspheres are at the nanoscale and have a specific surface area up to 659.06 m2 / g and a pore volume reaching 0.2787 cm3 / g, and thus can be used as an adsorption carrier, a drug delivery carrier, an energy storage carrier or a catalytic carrier, etc.

Description

A resin-based carbon material microsphere, its preparation method and application Technical Field

[0001] This invention belongs to the fields of carbon materials, electrochemistry, and medicine, and specifically relates to a method for preparing resin-based carbon material microspheres and their applications. Background Technology

[0002] In recent years, carbon microspheres have shown promising applications in adsorption, catalysis, drug delivery, and energy storage due to their advantages such as high specific surface area, thermal stability, low density, and unique electronic properties. Among these, the preparation of carbon microspheres using resin as a precursor has attracted widespread attention due to the advantages of stable and inexpensive raw materials and the high residual carbon content of some resins. Existing technologies for preparing phenolic resin microspheres mainly involve hydrothermal and emulsion methods. The hydrothermal method involves polymerizing phenolic resin under high temperature and pressure to form nanospheres or microspheres, followed by carbonization steps to obtain phenolic resin-based hard carbon microspheres. The emulsion method, on the other hand, obtains phenolic resin microspheres through the physical interaction between water and oil phases, followed by carbonization steps to obtain phenolic resin-based hard carbon microspheres. However, both the hydrothermal and emulsion methods result in complex preparation processes and long production cycles for hard carbon microspheres.

[0003] Invention patent CN 113321202 A discloses a method for preparing phenolic resin-based hard carbon microspheres. First, phenolic resin oligomers are prepared using phenol and aldehyde monomers under catalytic conditions. Then, these oligomers are mixed with water to prepare a phenolic resin emulsion. Phenolic resin microspheres are obtained by spray drying, and carbon material microspheres are obtained after pre-oxidation and carbonization treatment. This invention starts with the preparation of phenolic resin oligomers, resulting in a relatively long process. Strict control of the solid content in the phenolic resin emulsion is necessary to avoid clogging of the feed pipe.

[0004] Invention patent CN 115535998 A discloses a structurally tunable phenolic resin-based spherical hard carbon anode material for sodium-ion batteries and its preparation method. The method involves stirring phenolic resin, water, and a catalyst at a constant temperature for 6-12 hours to obtain a crosslinked product, followed by washing, drying at 80°C for 24 hours, and carbonization to obtain the phenolic resin-based spherical hard carbon material. This invention is time-consuming and energy-intensive, making it unsuitable for large-scale industrial production.

[0005] Invention patent CN 115651143 A discloses a phenolic resin microsphere, a porous carbon material microsphere, and their preparation method and application. First, phenolic compounds, water, aldehyde compounds, alkaline catalysts and dispersion media are mixed and reacted to obtain phenolic resin microspheres. Then, the phenolic resin microspheres are carbonized to obtain carbon material microspheres. The preparation of phenolic resin microspheres involves the application of various chemical raw materials, and the operation is relatively complicated.

[0006] Summary of the Invention

[0007] To improve the preparation efficiency and reduce the cost of carbon microspheres, this invention provides a method for preparing resin-based carbon microspheres and its application. Using resin as the raw material, without the need for dispersants or other additives, a resin-ethanol solution is mixed with water at room temperature, stirred until homogeneous, and then freeze-dried. Following carbonization, carbon microspheres are obtained, significantly shortening the preparation process and reducing costs.

[0008] To achieve the above objectives, the technical solution of the present invention is as follows:

[0009] A method for preparing resin-based carbon material microspheres includes the following steps:

[0010] (1) The alcohol-soluble phenolic resin is mixed with ethanol and water to obtain a resin dispersion; the volume fraction of ethanol in the resin dispersion is 30% to 80%, and the concentration of the resin dispersion is 0.01 g / ml to 0.10 g / ml.

[0011] (2) The resin dispersion was freeze-dried to obtain resin microspheres;

[0012] (3) Carbonize the resin microspheres under a protective atmosphere to obtain carbon material microspheres.

[0013] Preferably, the volume fraction of ethanol in the resin dispersion is 40% to 70%, more preferably 50% to 60%.

[0014] Preferably, the concentration of the resin dispersion in step (1) is 0.01 g / ml to 0.05 g / ml.

[0015] Preferably, the alcohol-soluble phenolic resin has a carbon residue of not less than 30% under a nitrogen atmosphere at 800°C.

[0016] Preferably, the alcohol-soluble phenolic resin in step (1) is dissolved in anhydrous ethanol to obtain a resin-ethanol solution; then the resin-ethanol solution is mixed evenly with water or an aqueous ethanol solution to obtain a resin dispersion.

[0017] Preferably, the freeze-drying temperature in step (2) is below -20°C and the vacuum degree is below 0.5 mbar.

[0018] Preferably, the carbonization temperature in step (3) is above 800°C, the heating rate is 2 to 15°C / min, and the carbonization time is 30 to 180 min.

[0019] Preferably, the protective atmosphere for the carbonization process in step (3) is nitrogen or argon, the carbonization temperature is 900-1400℃, the holding time is 60-90 min, and the heating rate is 5-10℃ / min.

[0020] The resin-based carbon microspheres prepared by the above method are used as adsorption carriers, drug delivery carriers, energy storage carriers or catalytic carriers.

[0021] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0022] (1) This invention uses resin as raw material and does not require the addition of dispersants and other additives to successfully prepare carbon material microspheres. The process is simple, the time required is short, and it is easy to realize industrial promotion.

[0023] (2) The carbon material microspheres prepared by the present invention have good morphology, are regular spherical, and their diameters are mainly distributed in the range of 50-250nm, especially 100-200nm; in addition, the microspheres have high specific surface area.

[0024] (3) The raw materials required for this invention are cheap and easy to obtain, and there is basically no need to use other chemical raw materials, which greatly reduces the preparation cost. Attached Figure Description

[0025] Figure 1(a) and (b) show the morphology of the phenolic resin microspheres and carbon material microspheres prepared in Example 1, respectively.

[0026] Figure 2(a) and (b) show the morphology of the phenolic resin microspheres and carbon material microspheres prepared in Example 2, respectively.

[0027] Figures 3(a) and (b) show the morphology of the phenolic resin microspheres and carbon material microspheres obtained in Example 3, respectively.

[0028] Figures 4 and 5 are morphological images of the freeze-dried phenolic resins obtained in Comparative Example 1 and Comparative Example 2, respectively.

[0029] Figure 6 shows the diameter distribution of the phenolic resin microspheres obtained in Example 1.

[0030] Figure 7 is a diagram showing the specific surface area of ​​the phenolic resin microspheres obtained in Example 1. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto. For process parameters not specifically noted, conventional techniques can be referred to.

[0032] The alcohol-soluble phenolic resin was purchased from Sumitomo Corporation of Japan, model PR311, in powder form.

[0033] Example 1

[0034] (1) Dissolve 22.13g of alcohol-soluble phenolic resin in anhydrous ethanol to a total volume of 200ml to obtain a phenolic resin-ethanol solution with a concentration of 11.1%;

[0035] (2) Mix 20 ml of water with 20 ml of anhydrous ethanol and shake well to obtain an ethanol-water solution;

[0036] (3) Take 10 ml of phenolic resin-ethanol solution and 40 ml of ethanol-water solution, mix and shake well to obtain a resin dispersion with an ethanol volume fraction of 60%.

[0037] (4) The resin dispersion was placed in a freeze dryer for freeze drying. The cold trap temperature was set to -53℃ and the vacuum degree was 0.37mba. After it was completely dried, it was taken out to obtain phenolic resin microspheres.

[0038] (5) The phenolic resin microspheres were carbonized in a N2 atmosphere, and the temperature was increased to 1400℃ at a heating rate of 10℃ / min and held for 60min to obtain carbon material microspheres.

[0039] Example 2

[0040] (1) Dissolve 22.13g of alcohol-soluble phenolic resin in anhydrous ethanol to a total volume of 200ml to obtain a phenolic resin-ethanol solution with a concentration of 11.1%;

[0041] (2) Mix 15 ml of water with 25 ml of anhydrous ethanol and shake well to obtain an ethanol-water solution;

[0042] (3) Take 10 ml of phenolic resin-ethanol solution and 40 ml of ethanol-water solution, mix and shake well to obtain a resin dispersion with an ethanol volume fraction of 70%.

[0043] (4) The resin dispersion was placed in a freeze dryer for freeze drying. The cold trap temperature was set to -53℃ and the vacuum degree was 0.37mba. After it was completely dried, it was taken out to obtain phenolic resin microspheres.

[0044] (5) The phenolic resin microspheres were carbonized in a N2 atmosphere, and the temperature was increased to 1400℃ at a heating rate of 10℃ / min and held for 60min to obtain carbon material microspheres.

[0045] Example 3

[0046] (1) Dissolve 18.97g of alcohol-soluble phenolic resin in anhydrous ethanol until the total volume is 200ml to obtain a phenolic resin-ethanol solution with a concentration of 9.5%.

[0047] (2) Mix 55 ml of water with 25 ml of phenolic resin-ethanol solution and shake well to obtain a resin dispersion with an ethanol volume fraction of 31.25%;

[0048] (3) The resin dispersion was placed in a freeze dryer for freeze drying. The cold trap temperature was set to -53℃ and the vacuum degree was 0.37mba. After it was completely dried, it was taken out to obtain phenolic resin microspheres.

[0049] (4) The phenolic resin microspheres were carbonized in a N2 atmosphere, heated to 1000℃ at a heating rate of 5℃ / min, and held for 90min to obtain carbon material microspheres.

[0050] Example 4

[0051] (1) Dissolve 18.97g of alcohol-soluble phenolic resin in anhydrous ethanol until the total volume is 200ml to obtain a phenolic resin-ethanol solution with a concentration of 9.5%.

[0052] (2) Mix 55 ml of water with 25 ml of phenolic resin-ethanol solution and shake well to obtain a resin dispersion with an ethanol volume fraction of 31.25%;

[0053] (3) The resin dispersion was placed in a freeze dryer for freeze drying. The cold trap temperature was set to -53℃ and the vacuum degree was 0.37mba. After it was completely dried, it was taken out to obtain phenolic resin microspheres.

[0054] (4) The phenolic resin microspheres were carbonized in a N2 atmosphere, and the temperature was increased to 900℃ at a heating rate of 10℃ / min and held for 60min to obtain carbon material microspheres.

[0055] Comparative Example 1

[0056] (1) Dissolve 18.97g of alcohol-soluble phenolic resin in anhydrous ethanol until the total volume is 200ml to obtain a phenolic resin-ethanol solution with a concentration of 9.5%.

[0057] (2) Mix 5 ml of water with 35 ml of anhydrous ethanol to obtain an ethanol-water solution;

[0058] (3) Mix 40 ml of ethanol-water solution with 10 ml of phenolic resin-ethanol solution to obtain a resin dispersion with an ethanol volume fraction of 90%.

[0059] (4) The resin dispersion was freeze-dried in a freeze dryer to obtain the dried phenolic resin.

[0060] (5) The dried phenolic resin was carbonized under N2 atmosphere, and the temperature was raised to 1000℃ at a heating rate of 5℃ / min and held for 90min to obtain carbonized resin.

[0061] Comparative Example 2

[0062] (1) Dissolve 22.13g of alcohol-soluble phenolic resin in anhydrous ethanol until the total volume is 200ml to obtain a phenolic resin-ethanol solution with a concentration of 11.1%.

[0063] (2) Mix 40 ml of water with 10 ml of phenolic resin-ethanol solution to obtain a resin dispersion with an ethanol volume fraction of 20%.

[0064] (3) The resin dispersion was freeze-dried in a freeze dryer to obtain the dried phenolic resin.

[0065] (4) The dried phenolic resin was carbonized under N2 atmosphere, and the temperature was raised to 1000℃ at a heating rate of 5℃ / min and held for 90min to obtain carbonized resin.

[0066] As shown in Figures 1-5, when the volume fraction of anhydrous ethanol in the resin dispersion is not within the range of 30% to 80%, the phenolic resin obtained by freeze-drying cannot exhibit spherical or near-spherical shapes, and resin-based carbon material microspheres cannot be obtained after carbonization treatment. Therefore, the ethanol content in the resin dispersion of this invention is crucial.

[0067] The specific surface area and pore volume of the carbon material microspheres prepared in each embodiment were measured by a specific surface area and pore size analyzer, as shown in Table 1.

[0068] Table 1

[0069] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing resin-based carbon material microspheres, characterized in that, Includes the following steps: (1) The alcohol-soluble phenolic resin is mixed with ethanol and water to obtain a resin dispersion; the volume fraction of ethanol in the resin dispersion is 30% to 80%, and the concentration of the resin dispersion is 0.01 g / ml to 0.10 g / ml. (2) The resin dispersion was freeze-dried to obtain resin microspheres; (3) Carbonize the resin microspheres under a protective atmosphere to obtain carbon material microspheres.

2. The preparation method according to claim 1, characterized in that, The volume fraction of ethanol in the resin dispersion in step (1) is 40% to 70%.

3. The preparation method according to claim 2, characterized in that, The concentration of the resin dispersion in step (1) is 0.01 g / ml to 0.05 g / ml; the volume fraction of ethanol in the resin dispersion is 50% to 60%.

4. The preparation method according to claim 3, characterized in that, The alcohol-soluble phenolic resin has a carbon residue of not less than 30% under a nitrogen atmosphere at 800°C.

5. The preparation method according to claim 1, 2, 3, or 4, characterized in that, The alcohol-soluble phenolic resin described in step (1) is dissolved in anhydrous ethanol to obtain a resin-ethanol solution; then the resin-ethanol solution is mixed evenly with water or an aqueous ethanol solution to obtain a resin dispersion.

6. The preparation method according to claim 1, 2, 3, or 4, characterized in that, The freeze-drying temperature in step (2) is below -20°C and the vacuum degree is below 0.5 mbar.

7. The preparation method according to claim 6, characterized in that, The carbonization process in step (3) is carried out at a temperature of 800°C or higher, with a heating rate of 2 to 15°C / min and a carbonization time of 30 to 180 min.

8. The preparation method according to claim 7, characterized in that, In step (3), the protective atmosphere for carbonization is nitrogen or argon, the carbonization temperature is 900-1400℃, the holding time is 60-90 min, and the heating rate is 5-10℃ / min.

9. Resin-based carbon material microspheres prepared by the method according to any one of claims 1 to 8.

10. The application of the resin-based carbon material microspheres of claim 9 as an adsorption carrier, drug delivery carrier, energy storage carrier, or catalytic carrier.

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