Hollow silicon dioxide and preparation method thereof
By using a template agent and catalyst to self-assemble a spherical template and calcining it at high temperature to form hollow silica, the problems of complexity and high precision requirements of traditional synthesis processes are solved, achieving the effects of simplified synthesis and improved quality.
Patent Information
- Application Number
- CN202510653303.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-21
- Publication Date
- 2026-02-10
AI Technical Summary
Traditional hollow silica synthesis processes are complex, lengthy, and require high precision, which limits the stability of product quality.
A spherical template is self-assembled using a mixture of template agent and catalyst. Silica is formed on the surface of the spherical template through a silicon source hydrolysis reaction. The template is then removed by calcination at high temperature to form hollow silica.
It simplifies the synthesis process, improves the ease of operation and the quality stability of the product, and provides new synthesis mechanisms and performance regulation ideas.
Smart Images
Figure CN121493995A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of silicon dioxide synthesis technology, specifically relating to hollow silicon dioxide and its preparation method. Background Technology
[0002] Hollow silica is a type of silica-based material with a hollow structure, and it has wide applications in medicine, catalysis, environment, and new energy. Currently, the synthesis of traditional hollow silica relies on hard template methods (polystyrene, iron oxide, etc.) and soft template methods (microemulsion method, sol-gel method, etc.). The hard template method requires the pre-preparation of a mechanically strong template as a precursor attachment growth point, but this method involves a complex and lengthy template synthesis process. Soft template methods require precise control of microemulsion formation and the addition of soft template agents, and the soft template is thermodynamically unstable, making operation more difficult. Therefore, current hollow silica preparation processes generally face challenges such as complex processes and long workflows. Furthermore, the synthesis process demands extremely high precision in controlling operational details and reagent ratios, which directly affects the quality and performance of the final product.
[0003] Therefore, there is an urgent need for hollow silica and its preparation method to alleviate or solve the above problems. A simple and effective method for synthesizing hollow silica is required. Summary of the Invention
[0004] To address the technical problems of complex and lengthy preparation processes and extremely high operational precision requirements in the aforementioned commonly used techniques, which lead to limited quality stability of the products, this invention provides a method for preparing hollow silica, comprising:
[0005] A mixture containing a template agent and a catalyst is obtained, wherein the template agent self-assembles and precipitates spherical templates under the action of the catalyst; wherein the template agent includes cationic triphenylmethane organic compounds, and the cationic triphenylmethane organic compounds include Basic Blue 7;
[0006] A silicon source is added to the mixture, and the silicon source undergoes a hydrolysis reaction to form silicon dioxide on the surface of the spherical template. After the hydrolysis reaction is complete, the solid and liquid are separated, and the solid phase is collected to obtain a hollow silicon dioxide precursor.
[0007] The hollow silica precursor was calcined to obtain hollow silica.
[0008] Furthermore, the catalyst includes one or more of ammonia, sodium hydroxide, and sodium carbonate.
[0009] Furthermore, in the mixture, the concentration of the template agent is 0.007-0.015 mol / L; and in the mixture, the concentration of the catalyst is 0.3-0.9 mol / L.
[0010] Furthermore, the preparation of the mixture includes the following steps: mixing the template agent with deionized water and the catalyst in sequence, and stirring at a temperature of 40-80°C to obtain the mixture; the stirring time is 15-60 min.
[0011] Furthermore, the molar ratio of the silicon source to the catalyst is 1:5 to 1:10.
[0012] Furthermore, the silicon source includes fluorosilicic acid; the fluorosilicic acid is added to the mixture in the form of a fluorosilicic acid solution, the concentration of the fluorosilicic acid solution being 0.15-0.5 mol / L; in the mixture system of the silicon source and the mixture, the concentration of the silicon source is 0.03-0.1 mol / L; the addition rate of the fluorosilicic acid solution is 0.3-3 ml / min.
[0013] Furthermore, the hydrolysis reaction is carried out at a temperature of 40-85°C; the hydrolysis reaction lasts for 3-9 hours; and the hydrolysis reaction is carried out under stirring conditions.
[0014] Furthermore, the calcination temperature is 500-700℃, and the calcination time is 0.5-6h.
[0015] This invention provides a hollow silica, prepared by any of the hollow silica preparation methods described above.
[0016] Furthermore, the hollow silica structure is hollow, with a cavity diameter of 100-200 nm and a wall thickness of 10-15 nm.
[0017] Compared with the prior art, the present invention has at least the following advantages:
[0018] This invention provides a method for preparing hollow silica. In a template agent-catalyst mixed system, the template agent (such as cationic triphenylmethane organic compounds like Basic Blue 7) can self-assemble and precipitate spherical templates under the influence of the catalyst. The spherical templates belong to a positively charged quaternary ammonium salt structure. With the introduction of a silicon source, negatively charged silicon-containing ions (such as fluorosilicate SiF6) are introduced. 2- This invention utilizes electrostatic interactions to bind to spherical templates, subsequently hydrolyzing the template surface to form silica. Calcination is then used to remove the spherical template, leaving a shaped hollow silica structure. This invention is the first to utilize small molecules to automatically form hard template structures in situ in solution, specifically through the self-assembly process of quaternary ammonium salt templates such as Basic Blue 7. This method easily and efficiently overcomes the complex template synthesis problems associated with hard templates in the early stages, while also avoiding the thermodynamic instability issues of soft templates. It represents a novel synthetic method and provides a new approach for in-depth research into the formation mechanism and performance regulation of hollow silica. Attached Figure Description
[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.
[0020] Figure 1 This is a SEM image of the freeze-dried sample in Example 1 of this invention;
[0021] Figure 2 This is an SEM image of the calcined sample in Example 2 of this invention;
[0022] Figure 3 This is a TEM image of the calcined sample in Example 2 of this invention;
[0023] Figure 4 This is a SEM image of the calcined sample in Example 3 of this invention;
[0024] Figure 5 This is an SEM image of the calcined sample in Example 4 of this invention;
[0025] Figure 6 This is an SEM image of the calcined sample in Example 5 of this invention;
[0026] Figure 7 This is an SEM image of the calcined sample in Example 6 of this invention;
[0027] Figure 8 This is a SEM image of the calcined sample in Example 7 of this invention;
[0028] Figure 9 This is a SEM image of the calcined sample in Example 8 of this invention;
[0029] Figure 10 This is a SEM image of the calcined sample in Example 9 of this invention;
[0030] Figure 11 This is a TEM image of the calcined sample in Comparative Example 1 of this invention;
[0031] Figure 12 This is a SEM image of the calcined sample in Comparative Example 2 of this invention;
[0032] Figure 13 This is a SEM image of the calcined sample in Comparative Example 3 of this invention;
[0033] Figure 14This is a SEM image of the calcined sample in Comparative Example 4 of this invention;
[0034] Figure 15 This is a SEM image of the calcined sample in Comparative Example 5 of this invention;
[0035] Figure 16 This is a SEM image of the calcined sample in Comparative Example 6 of this invention. Detailed Implementation
[0036] 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 a part of the embodiments of the present invention, and not all of them. 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.
[0037] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.
[0038] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in the present invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention, as well as the prior art known to those skilled in the art and the description of the invention, may be implemented using any prior art methods, devices, and materials similar to or equivalent to the methods, devices, and materials in the embodiments of the present invention.
[0039] This invention provides a method for preparing hollow silica, comprising:
[0040] S1. Obtain a mixture containing a template agent and a catalyst, wherein the template agent self-assembles and precipitates a spherical template under the action of the catalyst.
[0041] In this invention, the template agent includes one or more cationic triphenylmethane organic compounds such as Basic Blue 7. For example, the template agent may be Basic Blue 7.
[0042] In this invention, the catalyst includes one or more of ammonia, sodium hydroxide, and sodium carbonate; in some embodiments of this invention, the catalyst may include ammonia.
[0043] In this invention, the preparation of the mixture includes the following steps: mixing the template agent sequentially with deionized water and the catalyst, and stirring at 100-600 rpm for 15-60 min (more specifically 20-60 min or 15-30 min) at a temperature of 40-70°C to obtain the mixture. In some embodiments, the mixture of template agent, deionized water, and catalyst can be stirred at a temperature of 50-70°C to ensure that the template remains stable in the aqueous solution; excessively high temperatures will cause the template to become unstable and decompose.
[0044] In some embodiments, the template agent can be dissolved in deionized water and then stirred for 5-10 minutes; then the catalyst can be dissolved in the mixture of the template agent and deionized water and stirred for 15-60 minutes (moreover, 20-60 minutes or 15-30 minutes); the temperature of the second stirring can be 40-70°C.
[0045] In some embodiments, the mixing order of the template agent, deionized water, and catalyst can be: first, the template agent is mixed with deionized water, and then ammonia water is added to the mixture of the template agent and deionized water.
[0046] In this invention, the concentration of the template agent in the mixture is 0.007-0.015 mol / L (further 0.010-0.015 mol / L), and the concentration of the catalyst in the mixture is 0.3-0.9 mol / L (further 0.4-0.7 mol / L); the volume of the mixture is 200 ml. This invention controls the concentration of the template agent in the mixture to be 0.007-0.015 mol / L, ensuring that the template agent concentration is appropriate. Too low a concentration would result in an excess of Si, forming free silica nanoparticles, while too high a concentration might result in insufficient Si concentration, preventing the formation of a stable and complete silica structure.
[0047] S2. Add the silicon source to the mixture, and the silicon source undergoes a hydrolysis reaction to form silicon dioxide on the surface of the spherical template; after the hydrolysis reaction is completed, the solid and liquid are separated, and the solid phase is collected to obtain a hollow silicon dioxide precursor.
[0048] In this invention, the silicon source may include a fluorosilicic acid solution with a concentration of 0.15-0.5 mol / L. In some embodiments, the preparation of the fluorosilicic acid solution may include the steps of adding fluorosilicic acid to deionized water to form a fluorosilicic acid solution with a concentration of 0.15-0.5 mol / L, wherein the volume of the fluorosilicic acid solution may be 50 ml, and the addition rate of the fluorosilicic acid may be 0.3-3 ml / min; in some embodiments, in the mixture system of the silicon source and the mixed solution, the concentration of the silicon source is 0.03-0.1 mol / L.
[0049] In this invention, the molar ratio of silicon source to catalyst can be 1:5 to 1:10; in some embodiments, the molar ratio of silicon source to catalyst can be 1:8 to 1:10.
[0050] In this invention, the temperature of the hydrolysis reaction is 40-85°C, further 40-80°C, further 60-80°C; the duration of the hydrolysis reaction is 3-9 hours, further 3-8 hours or 7-9 hours; and the hydrolysis reaction is carried out under stirring conditions.
[0051] In this invention, the silicon source can be added to the mixture at a rate of 0.3-3 ml / min, and the mixture can be stirred at a stirring rate of 100-600 rpm for 3-9 h (more specifically, 3-8 h or 7-9 h) under the temperature conditions of the hydrolysis reaction.
[0052] In this invention, the prepared hollow silica precursor can be dried, and the drying method can be freeze drying or oven drying at a constant temperature.
[0053] S3. The hollow silica precursor is calcined to obtain hollow silica.
[0054] In this invention, the calcination temperature can be 500-700℃, and the calcination time can be 0.5-6h (more specifically 0.5-2h); in some embodiments of this invention, the calcination temperature can be 500-650℃.
[0055] In step S1 of the present invention, when the template agent includes one or more cationic triphenylmethane organic compounds such as Basic Blue 7, a spherical template with a positively charged surface will be precipitated after the template agent is added to the catalyst.
[0056] In step S2 of the present invention, when the silicon source is a fluorosilicic acid solution, the negatively charged fluorosilicate ions (SiF6) 2- It combines with a spherical template and hydrolyzes on the surface of the spherical template to form silicon dioxide.
[0057] In step S3 of the present invention, the high-temperature calcination process removes the residual template agent precipitated inside the silicon dioxide, forming a hollow structure in the silicon dioxide to obtain hollow silicon dioxide.
[0058] This invention provides a hollow silica, prepared by any of the hollow silica preparation methods described above.
[0059] To facilitate a further understanding of the present invention by those skilled in the art, the following examples are provided:
[0060] Example 1
[0061] Dissolve 1.28 g of Basic Blue 7 in 190 ml of deionized water and stir for 5 min. After stirring, add 10 ml of ammonia to obtain a mixture with a concentration of Basic Blue 7 of 0.012 mol / L and ammonia concentration of 0.67 mol / L. Stir the mixture at 50 °C for 20 min to obtain a reddish-brown precipitate. Filter the reddish-brown precipitate and freeze-dry it to obtain a solid powder.
[0062] Figure 1 This is a SEM image of the sample after freeze-drying in Example 1. From... Figure 1 It can be observed that the precipitate formed by Basic Blue 7 in ammonia water is spherical particles.
[0063] Example 2
[0064] Dissolve 1.28 g of Basic Blue 7 in 190 ml of deionized water and stir for 5 min. After stirring, add 10 ml of ammonia and stir again at 50 °C for 20 min to obtain a mixture. The concentration of Basic Blue 7 in the mixture is 0.012 mol / L, and the concentration of ammonia is 0.67 mol / L. Add 50 ml of a fluorosilicic acid solution with a molar concentration of approximately 0.32 mol / L to the mixture at a rate of 1 ml / min. The concentration of fluorosilicic acid in the mixture is 0.064 mol / L. After the addition is complete, raise the temperature to 80 °C and stir at 400 rpm for 8 h.
[0065] After the reaction was completed, the solid and liquid phases were separated and the solid phase was collected to obtain a hollow silica precursor. The hollow silica precursor was dried at 80℃ for 12 hours. The dried hollow silica precursor was then calcined in a muffle furnace at 600℃ for 1 hour at a heating rate of 10℃ / h to obtain hollow silica.
[0066] Figure 2 and Figure 3 The images shown are SEM and TEM images of the hollow silica obtained after calcination in Example 2. From... Figure 2 It can be observed that the prepared silica is silica with a spherical and hollow structure, through... Figure 3 The TEM image reveals that the structure is a uniform hollow structure.
[0067] The hollow silica structure prepared in Example 2 has a hollow structure with an average cavity diameter of 105.5 nm and an average wall thickness of approximately 13.6 nm.
[0068] Example 3
[0069] Dissolve 1.28 g of Basic Blue 7 in 193.5 ml of deionized water and stir for 5 min. After stirring, add 6.5 ml of ammonia and stir for 20 min at 50 °C to obtain a mixture with a concentration of Basic Blue 7 of 0.012 mol / L and ammonia concentration of 0.43 mol / L. Add 50 ml of a fluorosilicic acid solution with a molar concentration of approximately 0.21 mol / L to the mixture at a rate of 1 ml / min. The concentration of fluorosilicic acid in the mixture is 0.042 mol / L. After the addition is complete, heat to 80 °C and stir at 400 rpm for 8 h.
[0070] After the reaction was completed, the solid and liquid phases were separated and the solid phase was collected to obtain a hollow silica precursor. The hollow silica precursor was dried at 80℃ for 12 hours. The dried solid was then calcined in a muffle furnace at 600℃ for 1 hour at a heating rate of 10℃ / h to obtain hollow silica.
[0071] Figure 4 This is a SEM image of the silica sample after calcination in Example 3. Figure 4 It can be observed that the obtained silicon dioxide is silicon dioxide with a spherical and hollow structure.
[0072] Example 4
[0073] Dissolve 1.28 g of Basic Blue 7 in 190 ml of deionized water and stir for 5 min. After stirring, add 13 ml of ammonia and stir again at 50 °C for 20 min to obtain a mixture. The concentration of Basic Blue 7 in the mixture is 0.012 mol / L, and the concentration of ammonia is 0.87 mol / L. Add 50 ml of a fluorosilicic acid solution with a molar concentration of approximately 0.42 mol / L to the mixture at a rate of 1 ml / min. The concentration of fluorosilicic acid in the mixture is 0.083 mol / L. After the addition is complete, raise the temperature to 80 °C and stir at 400 rpm for 8 h.
[0074] After the reaction was completed, the solid and liquid phases were separated and the solid phase was collected to obtain a hollow silica precursor. The hollow silica precursor was dried at 80℃ for 12 hours. The dried solid was then calcined in a muffle furnace at 600℃ for 1 hour at a heating rate of 10℃ / h to obtain hollow silica.
[0075] Figure 5 This is a SEM image of the silica sample after calcination in Example 4, from... Figure 5 It can be observed that the obtained silicon dioxide is silicon dioxide with a spherical and hollow structure.
[0076] Example 5
[0077] Compared to Example 2, all other conditions remain the same in this example, except for the adjustment of the temperature of the second stirring: the temperature of the second stirring is changed to 60°C.
[0078] Figure 6 This is a SEM image of the silica sample after calcination in Example 5, from... Figure 6 It can be observed that the obtained silicon dioxide is silicon dioxide with a spherical and hollow structure.
[0079] Example 6
[0080] Compared to Example 2, all other conditions remain unchanged in this example, except for the adjustment of the temperature of the second stirring: the temperature of the second stirring is changed to 70°C.
[0081] Figure 7 This is a SEM image of the silica sample after calcination in Example 6, from... Figure 7 It can be observed that the obtained silicon dioxide is silicon dioxide with a spherical and hollow structure.
[0082] Example 7
[0083] Compared to Example 2, all other conditions remain unchanged in this example, except that the concentration of Basic Blue 7 in the mixture is adjusted to 0.0094 mol / L.
[0084] Figure 8 This is a SEM image of the silica sample after calcination in Example 7, from... Figure 8 It can be found that the reaction at a concentration of 0.0094 mol / L Basic Blue 7 yields silica with a relatively intact hollow structure.
[0085] Example 8
[0086] Compared to Example 2, all other conditions remain the same in this example, except that ammonia is replaced with sodium hydroxide:
[0087] Dissolve 1.28 g of Basic Blue 7 in 190 ml of deionized water and stir for 5 min. After stirring, add sodium hydroxide solution and stir for 20 min at 50 °C to obtain a mixture with a concentration of Basic Blue 7 of 0.012 mol / L and a sodium hydroxide concentration of 0.67 mol / L. Add 50 ml of fluorosilicic acid solution with a molar concentration of approximately 0.32 mol / L to the mixture at a rate of 1 ml / min. The concentration of fluorosilicic acid in the mixture is 0.064 mol / L. After the addition is complete, raise the temperature to 80 °C and stir at 400 rpm for 8 h.
[0088] After the reaction was completed, the solid and liquid phases were separated and the solid phase was collected to obtain a hollow silica precursor. The hollow silica precursor was dried at 80℃ for 12 hours. The dried hollow silica precursor was then calcined in a muffle furnace at 600℃ for 1 hour at a heating rate of 10℃ / h to obtain hollow silica.
[0089] Figure 9 This is a SEM image of the silica sample after calcination in Example 8, from... Figure 9 It can be seen that hollow silica structures can also be obtained through sodium hydroxide catalysis, but the overall structure is not spherical, the structure is not uniform, and there are silica nanoparticles on the surface of the hollow structure.
[0090] Example 9
[0091] Compared to Example 2, all other conditions remain the same in this example, except that ammonia is replaced with sodium carbonate:
[0092] Dissolve 1.28 g of Basic Blue 7 in 190 ml of deionized water and stir for 5 min. After stirring, add sodium carbonate solution and stir again at 50 °C for 20 min to obtain a mixture. The concentration of Basic Blue 7 in the mixture is 0.012 mol / L, and the concentration of sodium carbonate in the mixture is 0.67 mol / L. Add 50 ml of fluorosilicic acid solution with a molar concentration of approximately 0.32 mol / L to the mixture at a rate of 1 ml / min. The concentration of fluorosilicic acid in the mixture is 0.064 mol / L. After the addition is complete, raise the temperature to 80 °C and stir at 400 rpm for 8 h.
[0093] After the reaction was completed, the solid and liquid phases were separated and the solid phase was collected to obtain a hollow silica precursor. The hollow silica precursor was dried at 80℃ for 12 hours. The dried hollow silica precursor was then calcined in a muffle furnace at 600℃ for 1 hour at a heating rate of 10℃ / h to obtain hollow silica.
[0094] Figure 10 This is a SEM image of the silica sample after calcination in Example 9, from... Figure 10 It can be seen that hollow silica structures can also be obtained through sodium carbonate catalysis, but the overall structure is not spherical, the structure is not uniform, and there are silica nanoparticles on the surface of the hollow structure.
[0095] Comparative Example 1
[0096] Compared to Example 2, all other conditions remained unchanged in this comparative example, except that the concentration of Basic Blue 7 in the mixture was adjusted to 0.0031 mol / L.
[0097] Figure 11 This is a SEM image of the silica sample after calcination in Comparative Example 1.Figure 11 It can be observed that the reaction at a concentration of 0.0031 mol / L Basic Blue 7 does not yield silica with a complete hollow structure, and at this point, it mainly consists of nanoparticles, indicating that the concentration of Basic Blue 7 is too low.
[0098] Comparative Example 2
[0099] Compared to Example 2, all other conditions in this comparative example remain unchanged, except for the temperature of the second stirring: the temperature of the second stirring is changed to 80°C.
[0100] Figure 12 This is a SEM image of the silica sample after calcination in Comparative Example 2. Figure 12 It can be observed that silicon dioxide with a complete hollow structure cannot be obtained at a reaction temperature of 80℃, indicating that the second stirring temperature cannot be too high.
[0101] Comparative Example 3
[0102] Compared to Example 2, all other conditions remained unchanged in this comparative example, except that the concentration of Basic Blue 7 in the mixture was adjusted to 0.0063 mol / L.
[0103] Figure 13 This is a SEM image of the silica sample after calcination in Comparative Example 3. Figure 13 It can be observed that the reaction at a concentration of 0.0063 mol / L Basic Blue 7 does not yield silica with a complete hollow structure, and at this point, it mainly consists of nanoparticles, indicating that the concentration of Basic Blue 7 is too low.
[0104] Comparative Example 4
[0105] Compared to Example 2, all other conditions remain the same in this example, except for the type of template agent: Basic Blue 7 is changed to Crystal Violet, which has a similar structure, while maintaining the same concentration.
[0106] Figure 14 This is a SEM image of the calcined silica sample from the comparative example. Figure 14 It can be observed that using crystal violet as a template cannot form silicon dioxide with a hollow structure.
[0107] Comparative Example 5
[0108] Compared to Example 2, all other conditions remained unchanged in this comparative example, except for the type of template agent: Basic Blue 7 was changed to Malachite Green, which has a similar structure, while maintaining the same concentration.
[0109] Figure 15 This is a SEM image of the calcined silica sample from the comparative example. Figure 15 It can be observed that malachite green cannot form silica with a hollow structure.
[0110] Comparative Example 6
[0111] Compared to Example 2, all other conditions remained unchanged in this comparative example, except for the type of template agent: Basic Blue 7 was replaced with Victoria Blue B, which has a similar structure, while the concentration remained the same.
[0112] Figure 16 This is a SEM image of the calcined silica sample from the comparative example. Figure 16 It can be observed that malachite green cannot form silica with a hollow structure.
[0113] The above technical solutions of the present invention are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made under the technical concept of the present invention using the contents of the present invention specification and drawings, or direct / indirect applications in other related technical fields, are included in the patent protection scope of the present invention.
Claims
1. A method for preparing hollow silica, characterized in that, include: A mixture containing a template agent and a catalyst is obtained, wherein the template agent self-assembles and precipitates spherical templates under the action of the catalyst; wherein the template agent includes cationic triphenylmethane organic compounds, and the cationic triphenylmethane organic compounds include Basic Blue 7; A silicon source is added to the mixture, and the silicon source undergoes a hydrolysis reaction to form silicon dioxide on the surface of the spherical template. After the hydrolysis reaction is complete, the solid and liquid are separated, and the solid phase is collected to obtain a hollow silicon dioxide precursor. The hollow silica precursor was calcined to obtain hollow silica.
2. The method for preparing hollow silica according to claim 1, characterized in that, The catalyst includes one or more of ammonia, sodium hydroxide, and sodium carbonate.
3. The method for preparing hollow silica according to claim 1, characterized in that, In the mixture, the concentration of the template agent is 0.007-0.015 mol / L; in the mixture, the concentration of the catalyst is 0.3-0.9 mol / L.
4. The method for preparing hollow silica according to claim 1, characterized in that, The preparation of the mixture includes the following steps: mixing the template agent with deionized water and the catalyst in sequence, and stirring at a temperature of 40-80°C to obtain the mixture; the stirring time is 15-60 min.
5. The method for preparing hollow silica according to claim 1, characterized in that, The molar ratio of the silicon source to the catalyst is 1:5 to 1:
10.
6. The method for preparing hollow silica according to claim 1, characterized in that, The silicon source includes fluorosilicic acid; the fluorosilicic acid is added to the mixture in the form of a fluorosilicic acid solution, the concentration of the fluorosilicic acid solution being 0.15-0.5 mol / L; in the mixture of the silicon source and the mixture, the concentration of the silicon source is 0.03-0.1 mol / L; the addition rate of the fluorosilicic acid solution is 0.3-3 ml / min.
7. The method for preparing hollow silica according to claim 6, characterized in that, The hydrolysis reaction is carried out at a temperature of 40-85℃; the hydrolysis reaction lasts for 3-9 hours; and the hydrolysis reaction is carried out under stirring conditions.
8. The method for preparing hollow silica according to claim 1, characterized in that, The calcination temperature is 500-700℃, and the calcination time is 0.5-6h.
9. A hollow silicon dioxide, characterized in that, It is prepared by the method for preparing hollow silica according to any one of claims 1 to 8.
10. The hollow silicon dioxide according to claim 9, characterized in that, The hollow silica structure is hollow, with a cavity diameter of 100-200 nm and a wall thickness of 10-15 nm.