M@SiO2 Hollow Composite Microspheres Driven by Molecular Assembly, Preparation Method Thereof and Application Thereof

Abstract

The present invention discloses a molecular-driven assembled M@SiO2 hollow composite microsphere, its preparation method and application. By using metal acetylacetonate salts to diffuse into the hollow structure as the core, anionic surfactants as templates, and tetraethyl orthosilicate as the silicon source, hydrolysis and condensation reactions occur in a double-solvent solution. After removing the template agent, monodisperse hollow mesoporous silica microspheres with controllable sizes are obtained, which have advantages such as a monodisperse structure and controllable sizes. The present invention uses acetylacetonate salts as metal sources to prepare mesoporous hollow silica microsphere catalysts with high stability, high dispersion, and adjustable cavity sizes. Further, through post-treatment with chlorosulfonic acid, functional modification of the surface and internal pores of the silica microspheres is achieved, and it has application prospects in the field of catalytic oxidation.

Description

Technical Field

[0001] The present invention relates to a molecular-driven assembled M@SiO2 hollow composite microsphere, a preparation method thereof, and an application in the field of catalytic oxidation. Background Art

[0002] Mesoporous hollow silica microsphere materials have shown great application potential in the fields of catalysis, separation, adsorption, and controlled drug release due to their high specific surface area, high melting point, high stability, non-toxicity, etc., and thus have received extensive attention.

[0003] Currently, the template method is the most commonly used method for preparing inorganic hollow microspheres. The size and dispersibility of the template material determine the size and dimensions of the cavity of the hollow silica microsphere, and the entire synthesis operation method is relatively simple. The template method is divided into the hard template method and the soft template method. Among them, the most commonly used hard template materials are polystyrene (PS) microspheres, silicon spheres, inorganic salts, etc. Although the process is simple, there are still many deficiencies: (1) It is easy to damage the shell structure and introduce impurities when removing the template, and it will also cause deformation or collapse of the hollow microsphere; (2) It is difficult to balance and control the hydrolysis and polycondensation reaction of the silicon source on the template surface; (3) It is difficult to control the integrity and uniformity of the silica layer coating on the template surface, and strict reaction conditions need to be controlled. Based on the above problems, the soft template method has been developed. Commonly used soft template agents include microemulsions, micelles, vesicles, and bubbles, etc. For hollow mesoporous silica microspheres of different sizes, there are significant differences in performance in applications such as catalysis, separation, and controlled drug release. In addition, the controllability of the size of the hollow silica microsphere material can flexibly achieve the controllability of performance in practical applications and expand the scope of application and performance of the material.

[0004] In view of this, the present invention uses metal acetylacetonate as the metal source and tetraethyl orthosilicate as the silicon source, and prepares size-controllable M@SiO2 hollow composite microspheres by driving molecular assembly by controlling the concentration of the raw material solution, and applies them in catalytic oxidation reactions. Summary of the Invention

[0005] The purpose of the present invention is to provide a molecular-driven assembled M@SiO2 hollow composite microsphere, a preparation method thereof, and an application. The present invention can obtain M@SiO2 hollow composite microspheres with a monodisperse structure and controllable size, and examples of its application in catalytic oxidation reactions are given.

[0006] The technical solution of the present invention is as follows:

[0007] A preparation method of a molecular-driven assembled M@SiO2 hollow composite microsphere, comprising:

[0008] Dissolve the metal acetylacetonate in an organic solvent, then add a hydrochloric acid solution of an anionic surfactant, tetraethyl orthosilicate, and a co-structure directing agent, and react at 50-130 °C for 15-30 h. After that, cool to room temperature, centrifuge, wash, and vacuum dry to obtain solid microspheres; disperse the obtained solid microspheres in an ethanolamine-ethanol solution, reflux at 80-100 °C for 10-20 h, then cool to room temperature, centrifuge, wash, and vacuum dry to obtain M@SiO2 hollow composite microspheres;

[0009] Among them,

[0010] The metal element in the metal acetylacetonate is one or two of Fe, Co, and Ni;

[0011] The organic solvent is selected from one of ethanol, methanol, and N,N-dimethylformamide;

[0012] The concentration of the solution obtained by dissolving the metal acetylacetonate in the organic solvent is 0.02-0.2 mol / L;

[0013] The anionic surfactant is selected from sodium N-lauroylsarcosinate or sodium dodecyl hydrogen sulfate; the anionic surfactant not only acts as a template but also promotes the formation of metal nanoclusters inside SiO2;

[0014] The hydrochloric acid solution of the anionic surfactant is prepared by dissolving the anionic surfactant in dilute hydrochloric acid (0.01 mol / L) (with strong stirring for 1-2 h), and the concentration of the anionic surfactant is 20-50 mmol / L;

[0015] The co-structure directing agent is 3-aminopropyltriethoxysilane;

[0016] The molar ratio of the metal acetylacetonate, anionic surfactant, tetraethyl orthosilicate, and co-structure directing agent is 2-20:4-20:100:5-10;

[0017] In the ethanolamine-ethanol solution, the concentration of ethanolamine is 0.001-0.005 mol / L;

[0018] The concentration of the solid microspheres in the ethanolamine-ethanol solution is 5-10 g / L;

[0019] Washing can be carried out with one or more of ethanol, methanol, and N,N-dimethylformamide, and the temperature of vacuum drying is 80 °C.

[0020] Furthermore, the M@SiO2 hollow composite microspheres prepared by the above method can be functionally modified, and the specific modification method is as follows:

[0021] Disperse M@SiO2 hollow composite microspheres in dichloromethane, and while ultrasonically treating at room temperature, dropwise add a dichloromethane solution of chlorosulfonic acid. React for 20 - 60 min, then centrifuge, wash, and vacuum dry to obtain functionalized M@SiO2 hollow composite microspheres;

[0022] The concentration of M@SiO2 hollow composite microspheres in dichloromethane is 20 - 50 g / L;

[0023] The concentration of the dichloromethane solution of chlorosulfonic acid is 0.001 - 0.005 mol / L;

[0024] The feeding ratio of chlorosulfonic acid to M@SiO2 hollow composite microspheres is 0.01 - 0.05:1, mmol / g;

[0025] The washing is carried out with dichloromethane, and the temperature of vacuum drying is 80 °C.

[0026] Through the post-treatment with chlorosulfonic acid, not only can sulfonic acid groups be further grafted onto the microsphere surface, but also the silica surface can be treated by chemical etching to expose the metal nanoparticles inside the microspheres. The exposure of metal nanoparticles is significantly improved, which can provide more reaction sites, thus accelerating the progress of the catalytic reaction. Through this strategy, the overall performance of the catalyst can be effectively enhanced.

[0027] The present invention relates to M@SiO2 hollow composite microspheres and functionalized M@SiO2 hollow composite microspheres prepared by the above preparation method.

[0028] The M@SiO2 hollow composite microspheres or functionalized M@SiO2 hollow composite microspheres of the present invention have good catalytic oxidation performance and stability, and can be used as heterogeneous catalysts in the field of catalytic oxidation, specifically for example: for catalyzing the photocatalytic degradation of H2O2 of reactive dyes.

[0029] The present invention has the following advantages:

[0030] 1. The controllability of size can be achieved, and hollow silica nanosphere materials with a size of 100 - 1200 nm can be obtained, and appropriate materials and their synthesis methods can be selected according to application requirements.

[0031] 2. The functional modification of the surface and internal pores of the hollow core-shell microspheres can be realized. The single-metal or multi-metal M@SiO2 hollow composite microsphere catalyst modified by sulfonic acid functionalization effectively broadens the application range of the catalyst. Description of the Drawings

[0032] Figure 1 : TEM electron micrograph of the mesoporous hollow Fe@SiO2 microspheres prepared in Example 2 of the present invention.

[0033] Figure 2: STEM and EDS diagrams of the mesoporous hollow Fe@SiO2 microspheres prepared in Example 2 of the present invention.

[0034] Figure 3 : TEM electron micrograph of the outer shell pores of the Fe@SiO2-SO3H microspheres prepared in Example 19 of the present invention.

[0035] Figure 4 : SEM electron micrograph of the mesoporous hollow Co / Fe@SiO2 microspheres prepared in Example 5 of the present invention. Detailed implementation manners

[0036] The present invention will be further described below through specific examples, but the protection scope of the present invention is not limited thereto.

[0037] Example 1:

[0038] Dissolve iron acetylacetonate in ethanol to prepare a 100 mL metal-organic solution with a concentration of 0.01 mol / L, add 100 mL of 20 mmol / L N-lauroylsarcosine sodium-hydrochloric acid solution to form a mixed solution, then add 2.23 mL of tetraethyl orthosilicate and 0.234 mL of 3-aminopropyltriethoxysilane, react at 50 °C for 15 h. After the reaction is completed, centrifuge, wash, and dry in vacuum at 80 °C. Then disperse 0.5 g of the product in 100 mL of an ethanolamine-ethanol solution with a concentration of 0.001 mol / L, heat under reflux at 80 °C for 10 h, centrifuge, wash, and dry in vacuum to obtain a heterogeneous catalyst of hollow composite microspheres, denoted as: 0.01Fe@SiO2.

[0039] Example 2:

[0040] Dissolve iron acetylacetonate in ethanol to prepare a 100 mL metal-organic solution with a concentration of 0.1 mol / L, add 100 mL of 20 mmol / L N-lauroylsarcosine sodium-hydrochloric acid solution to form a mixed solution, then add 2.23 mL of tetraethyl orthosilicate and 0.234 mL of 3-aminopropyltriethoxysilane, react at 50 °C for 15 h. After the reaction is completed, centrifuge, wash, and dry in vacuum at 80 °C. Then disperse 0.5 g of the product in 100 mL of an ethanolamine-ethanol solution with a concentration of 0.001 mol / L, heat under reflux at 80 °C for 10 h, centrifuge, wash, and dry in vacuum to obtain a heterogeneous catalyst of hollow composite microspheres, denoted as: 0.1Fe@SiO2.

[0041] Example 3:

[0042] Dissolve iron acetylacetonate in ethanol to prepare a 100 mL metal-organic solution with a concentration of 0.2 mol / L. Add 100 mL of 20 mmol / L sodium N-lauroylsarcosinate-hydrochloric acid solution to form a mixed solution. Then add 2.23 mL of tetraethyl orthosilicate and 0.234 mL of 3-aminopropyltriethoxysilane, and react at 50 °C for 15 h. After the reaction is completed, centrifuge, wash, and dry in vacuum at 80 °C. Then disperse 0.5 g of the product in 100 mL of an ethanolamine-ethanol solution with a concentration of 0.001 mol / L, heat under reflux at 80 °C for 10 h, centrifuge, wash, and dry in vacuum to obtain a hollow composite microsphere heterogeneous catalyst, denoted as: 0.2Fe@SiO2.

[0043] Example 4:

[0044] Dissolve cobalt acetylacetonate in ethanol to prepare a 100 mL metal-organic solution with a concentration of 0.1 mol / L. Add 100 mL of 20 mmol / L sodium N-lauroylsarcosinate-hydrochloric acid solution to form a mixed solution. Then add 2.23 mL of tetraethyl orthosilicate and 0.234 mL of 3-aminopropyltriethoxysilane, and react at 50 °C for 15 h. After the reaction is completed, centrifuge, wash, and dry in vacuum at 80 °C. Then disperse 0.5 g of the product in 100 mL of an ethanolamine-ethanol solution with a concentration of 0.001 mol / L, heat under reflux at 80 °C for 10 h, centrifuge, wash, and dry in vacuum to obtain a hollow composite microsphere heterogeneous catalyst, denoted as: Co@SiO2.

[0045] Example 5:

[0046] Dissolve nickel acetylacetonate in ethanol to prepare a 100 mL metal-organic solution with a concentration of 0.1 mol / L. Add 100 mL of 20 mmol / L sodium N-lauroylsarcosinate-hydrochloric acid solution to form a mixed solution. Then add 2.23 mL of tetraethyl orthosilicate and 0.234 mL of 3-aminopropyltriethoxysilane, and react at 50 °C for 15 h. After the reaction is completed, centrifuge, wash, and dry in vacuum at 80 °C. Then disperse 0.5 g of the product in 100 mL of an ethanolamine-ethanol solution with a concentration of 0.001 mol / L, heat under reflux at 80 °C for 10 h, centrifuge, wash, and dry in vacuum to obtain a hollow composite microsphere heterogeneous catalyst, denoted as: Ni@SiO2.

[0047] Example 6:

[0048] Dissolve cobalt acetylacetonate and iron acetylacetonate in ethanol according to a molar ratio of 1:1 to prepare a 100 mL metal-organic solution with a metal ion concentration of 0.1 mol / L. Add 100 mL of 20 mmol / L sodium N-lauroylsarcosinate-hydrochloric acid solution to form a mixed solution. Then add 2.23 mL of tetraethyl orthosilicate and 0.234 mL of 3-aminopropyltriethoxysilane, and react at 50 °C for 15 h. After the reaction is completed, centrifuge, wash, and dry in vacuum at 80 °C. Then disperse 0.5 g of the product in 100 mL of an ethanolamine-ethanol solution with a concentration of 0.001 mol / L, heat and reflux at 80 °C for 10 h, centrifuge, wash, and dry in vacuum to obtain a hollow composite microsphere heterogeneous catalyst, denoted as: Co / Fe@SiO2.

[0049] Example 7:

[0050] Dissolve iron acetylacetonate in ethanol to prepare a 100 mL metal-organic solution with a concentration of 0.1 mol / L. Add 100 mL of 20 mmol / L sodium N-lauroylsarcosinate-hydrochloric acid solution to form a mixed solution. Then add 2.23 mL of tetraethyl orthosilicate and 0.234 mL of 3-aminopropyltriethoxysilane, and react at 80 °C for 15 h. After the reaction is completed, centrifuge, wash, and dry in vacuum at 80 °C. Then disperse 0.5 g of the product in 100 mL of an ethanolamine-ethanol solution with a concentration of 0.001 mol / L, heat and reflux at 80 °C for 10 h, centrifuge, wash, and dry in vacuum to obtain a hollow composite microsphere heterogeneous catalyst, denoted as: 0.1Fe@SiO2-80.

[0051] Example 8:

[0052] Dissolve iron acetylacetonate in ethanol to prepare a 100 mL metal-organic solution with a concentration of 0.1 mol / L. Add 100 mL of 20 mmol / L sodium N-lauroylsarcosinate-hydrochloric acid solution to form a mixed solution. Then add 2.23 mL of tetraethyl orthosilicate and 0.234 mL of 3-aminopropyltriethoxysilane, and react at 130 °C for 15 h. After the reaction is completed, centrifuge, wash, and dry in vacuum at 80 °C. Then disperse 0.5 g of the product in 100 mL of an ethanolamine-ethanol solution with a concentration of 0.001 mol / L, heat and reflux at 80 °C for 10 h, centrifuge, wash, and dry in vacuum to obtain a hollow composite microsphere heterogeneous catalyst, denoted as: 0.1Fe@SiO2-130.

[0053] Example 9:

[0054] Dissolve iron(III) acetylacetonate in ethanol to prepare a 100 mL metal-organic solution with a concentration of 0.1 mol / L. Add 100 mL of 20 mmol / L sodium N-lauroylsarcosinate-hydrochloric acid solution to form a mixed solution. Then add 2.23 mL of tetraethyl orthosilicate and 0.234 mL of 3-aminopropyltriethoxysilane, and react at 80 °C for 30 h. After the reaction is completed, centrifuge, wash, and dry in vacuum at 80 °C. Then disperse 0.5 g of the product in 100 mL of an ethanolamine-ethanol solution with a concentration of 0.001 mol / L, heat under reflux at 80 °C for 10 h, centrifuge, wash, and dry in vacuum to obtain a hollow composite microsphere heterogeneous catalyst, denoted as: 0.1Fe@SiO2-80 / 30.

[0055] Example 10:

[0056] Dissolve iron(III) acetylacetonate in ethanol to prepare a 100 mL metal-organic solution with a concentration of 0.1 mol / L. Add 100 mL of 20 mmol / L sodium N-lauroylsarcosinate-hydrochloric acid solution to form a mixed solution. Then add 2.23 mL of tetraethyl orthosilicate and 0.234 mL of 3-aminopropyltriethoxysilane, and react at 80 °C for 18 h. After the reaction is completed, centrifuge, wash, and dry in vacuum at 80 °C. Then disperse 0.5 g of the product in 100 mL of an ethanolamine-ethanol solution with a concentration of 0.001 mol / L, heat under reflux at 80 °C for 10 h, centrifuge, wash, and dry in vacuum to obtain a hollow composite microsphere heterogeneous catalyst, denoted as: 0.1Fe@SiO2-80 / 18.

[0057] Example 11:

[0058] Dissolve iron(III) acetylacetonate in ethanol to prepare a 100 mL metal-organic solution with a concentration of 0.1 mol / L. Add 100 mL of 50 mmol / L sodium N-lauroylsarcosinate-hydrochloric acid solution to form a mixed solution. Then add 2.23 mL of tetraethyl orthosilicate and 0.234 mL of 3-aminopropyltriethoxysilane, and react at 50 °C for 15 h. After the reaction is completed, centrifuge, wash, and dry in vacuum at 80 °C. Then disperse 0.5 g of the product in 100 mL of an ethanolamine-ethanol solution with a concentration of 0.001 mol / L, heat under reflux at 80 °C for 10 h, centrifuge, wash, and dry in vacuum to obtain a hollow composite microsphere heterogeneous catalyst, denoted as: 0.1Fe@SiO2-N50.

[0059] Example 12:

[0060] Dissolve iron(III) acetylacetonate in ethanol to prepare a 100 mL metal-organic solution with a concentration of 0.1 mol / L. Add 100 mL of 20 mmol / L sodium dodecyl sulfate-hydrochloric acid solution to form a mixed solution. Then add 2.23 mL of tetraethyl orthosilicate and 0.234 mL of 3-aminopropyltriethoxysilane, and react at 50 °C for 15 h. After the reaction is completed, centrifuge, wash, and dry in vacuum at 80 °C. Then disperse 0.5 g of the product in 100 mL of an ethanolamine-ethanol solution with a concentration of 0.001 mol / L, heat and reflux at 80 °C for 10 h, centrifuge, wash, and dry in vacuum to obtain a hollow composite microsphere heterogeneous catalyst, denoted as: 0.1Fe@SiO2-S20.

[0061] Example 13:

[0062] Dissolve iron(III) acetylacetonate in ethanol to prepare a 100 mL metal-organic solution with a concentration of 0.1 mol / L. Add 100 mL of 20 mmol / L sodium N-lauroylsarcosinate-hydrochloric acid solution to form a mixed solution. Then add 2.23 mL of tetraethyl orthosilicate and 0.234 mL of 3-aminopropyltriethoxysilane, and react at 50 °C for 15 h. After the reaction is completed, centrifuge, wash, and dry in vacuum at 80 °C. Then disperse 0.5 g of the product in 100 mL of an ethanolamine-ethanol solution with a concentration of 0.005 mol / L, heat and reflux at 80 °C for 10 h, centrifuge, wash, and dry in vacuum to obtain a hollow composite microsphere heterogeneous catalyst, denoted as: 0.1Fe@SiO2-005.

[0063] Example 14:

[0064] Dissolve iron(III) acetylacetonate in ethanol to prepare a 100 mL metal-organic solution with a concentration of 0.1 mol / L. Add 100 mL of 20 mmol / L sodium N-lauroylsarcosinate-hydrochloric acid solution to form a mixed solution. Then add 2.23 mL of tetraethyl orthosilicate and 0.234 mL of 3-aminopropyltriethoxysilane, and react at 50 °C for 15 h. After the reaction is completed, centrifuge, wash, and dry in vacuum at 80 °C. Then disperse 1.0 g of the product in 100 mL of an ethanolamine-ethanol solution with a concentration of 0.001 mol / L, heat and reflux at 80 °C for 10 h, centrifuge, wash, and dry in vacuum to obtain a hollow composite microsphere heterogeneous catalyst, denoted as: 0.1Fe@SiO2-M10.

[0065] Example 15:

[0066] Dissolve iron(III) acetylacetonate in ethanol to prepare a 100 mL metal-organic solution with a concentration of 0.1 mol / L. Add 100 mL of 20 mmol / L sodium N-lauroylsarcosinate-hydrochloric acid solution to form a mixed solution. Then add 2.23 mL of tetraethyl orthosilicate and 0.234 mL of 3-aminopropyltriethoxysilane, and react at 50 °C for 15 h. After the reaction is completed, centrifuge, wash, and dry in vacuum at 80 °C. Then disperse 0.5 g of the product in 100 mL of an ethanolamine-ethanol solution with a concentration of 0.001 mol / L, reflux at 90 °C for 10 h, centrifuge, wash, and dry in vacuum to obtain a hollow composite microsphere heterogeneous catalyst, denoted as: 0.1Fe@SiO2-R90.

[0067] Example 16:

[0068] Dissolve iron(III) acetylacetonate in ethanol to prepare a 100 mL metal-organic solution with a concentration of 0.1 mol / L. Add 100 mL of 20 mmol / L sodium N-lauroylsarcosinate-hydrochloric acid solution to form a mixed solution. Then add 2.23 mL of tetraethyl orthosilicate and 0.234 mL of 3-aminopropyltriethoxysilane, and react at 50 °C for 15 h. After the reaction is completed, centrifuge, wash, and dry in vacuum at 80 °C. Then disperse 0.5 g of the product in 100 mL of an ethanolamine-ethanol solution with a concentration of 0.001 mol / L, reflux at 100 °C for 10 h, centrifuge, wash, and dry in vacuum to obtain a hollow composite microsphere heterogeneous catalyst, denoted as: 0.1Fe@SiO2-R100.

[0069] Example 17:

[0070] Dissolve iron(III) acetylacetonate in ethanol to prepare a 100 mL metal-organic solution with a concentration of 0.1 mol / L. Add 100 mL of 20 mmol / L sodium N-lauroylsarcosinate-hydrochloric acid solution to form a mixed solution. Then add 2.23 mL of tetraethyl orthosilicate and 0.234 mL of 3-aminopropyltriethoxysilane, and react at 50 °C for 15 h. After the reaction is completed, centrifuge, wash, and dry in vacuum at 80 °C. Then disperse 0.5 g of the product in 100 mL of an ethanolamine-ethanol solution with a concentration of 0.001 mol / L, reflux at 100 °C for 20 h, centrifuge, wash, and dry in vacuum to obtain a hollow composite microsphere heterogeneous catalyst, denoted as: 0.1Fe@SiO2-R100 / 20.

[0071] Example 18:

[0072] Dissolve iron(III) acetylacetonate in ethanol to prepare a 100 mL metal-organic solution with a concentration of 0.1 mol / L. Add 100 mL of 20 mmol / L sodium N-lauroylsarcosinate-hydrochloric acid solution to form a mixed solution. Then add 0.223 mL of tetraethyl orthosilicate and 0.047 mL of 3-aminopropyltriethoxysilane, and react at 50 °C for 15 h. After the reaction is completed, centrifuge, wash, and dry in vacuum at 80 °C. Then disperse 0.5 g of the product in 100 mL of an ethanolamine-ethanol solution with a concentration of 0.001 mol / L, heat under reflux at 90 °C for 10 h, centrifuge, wash, and dry in vacuum to obtain a hollow composite microsphere heterogeneous catalyst, denoted as: 0.1Fe@SiO2-CR.

[0073] Example 19:

[0074] Dissolve iron(III) acetylacetonate in ethanol to prepare a 100 mL metal-organic solution with a concentration of 0.1 mol / L. Add 100 mL of 20 mmol / L sodium N-lauroylsarcosinate-hydrochloric acid solution to form a mixed solution. Then add 2.23 mL of tetraethyl orthosilicate and 0.234 mL of 3-aminopropyltriethoxysilane, and react at 50 °C for 15 h. After the reaction is completed, centrifuge, wash, and dry in vacuum at 80 °C. Then disperse 0.5 g of the product in 100 mL of an ethanolamine-ethanol solution with a concentration of 0.001 mol / L, heat under reflux at 90 °C for 10 h, centrifuge, wash, and dry in vacuum to obtain a Fe@SiO2 hollow composite microsphere heterogeneous catalyst. Further, disperse 1 g of the Fe@SiO2 hollow composite microspheres in 40 mL of dichloromethane for functional modification. While ultrasonically treating at room temperature, gradually add dropwise 10 mL of a dichloromethane mixed solution containing 0.005 mol / L chlorosulfonic acid, react for 30 min. After the reaction is completed, centrifuge, wash the solid, and dry in vacuum to prepare a sulfonated Fe@SiO2 hollow composite microsphere heterogeneous catalyst.

[0075] Typical M@SiO2 (Examples 2, 6, and 19) and SiO2 were selected for the catalytic oxidation performance test. The experimental procedure for the photocatalytic degradation of reactive dyes with H2O2 is as follows: First, prepare 100 ml of a reactive brilliant red X-3B dye solution with a concentration of 100 mg / L, and adjust the pH of the reaction solution to 6.0 with dilute hydrochloric acid or sodium hydroxide. Then, weigh the catalyst and add it to the dye solution so that the concentration of the catalyst in the dye solution is 0.1 g / L. Ultrasonically disperse and mix the catalyst and the solution evenly. Place it in a constant temperature oscillator at 30 °C. Before the photocatalytic degradation experiment, first shake the reaction solution in the dark for 30 min to achieve the adsorption equilibrium of the catalyst. Place the light source above the solution, turn on the visible light lamp (the light source is a 150 W sodium lamp), add H2O2 to make its concentration 2.12 mmol / L, and start the degradation experiment under visible light conditions. The degradation time is 120 min. During the oxidative degradation process, absorb the reaction solution at certain time intervals for analysis and measurement of the absorbance. Calculate the decolorization rate and the metal leakage amount. The obtained results are shown in Table 1.

[0076] As shown in Table 1, the hollow mesoporous SiO2 microspheres can effectively improve the activity of the catalyst after sulfonic acid functionalization.

[0077] Table 1 Performance comparison of M@SiO2 type catalysts

[0078]

Claims

1. A preparation method of M@SiO2 hollow composite microspheres driven by molecular self-assembly, characterized in that, Including: Dissolve the metal acetylacetonate in an organic solvent, then add a hydrochloric acid solution of an anionic surfactant, tetraethyl orthosilicate, and a co-structure directing agent, react at 50 - 130 °C for 15 - 30 h, then cool to room temperature, centrifuge, wash, and vacuum dry to obtain solid microspheres; disperse the obtained solid microspheres in an ethanolamine - ethanol solution, reflux at 80 - 100 °C for 10 - 20 h, then cool to room temperature, centrifuge, wash, and vacuum dry to obtain M@SiO2 hollow composite microspheres; Wherein, The metal element in the metal acetylacetonate is one or two of Fe, Co, and Ni; The organic solvent is selected from one of ethanol, methanol, and N,N - dimethylformamide; The anionic surfactant is selected from sodium N - lauroyl sarcosinate or sodium dodecyl hydrogen sulfate; The co - structure directing agent is 3 - aminopropyltriethoxysilane.

2. The preparation method of the molecular-driven assembled M@SiO2 hollow composite microspheres as described in claim 1, characterized in that, The concentration of the solution obtained by dissolving the metal acetylacetonate in the organic solvent is 0.02 - 0.2 mol / L.

3. The preparation method of the molecular-driven assembled M@SiO2 hollow composite microspheres as described in claim 1, characterized in that, The hydrochloric acid solution of the anionic surfactant is prepared by dissolving the anionic surfactant in 0.01 mol / L dilute hydrochloric acid, and the concentration of the anionic surfactant is 20 - 50 mmol / L.

4. The preparation method of the molecular-driven assembled M@SiO2 hollow composite microspheres according to claim 1, wherein, The molar ratio of the metal acetylacetonate, anionic surfactant, tetraethyl orthosilicate, and co - structure directing agent is 2 - 20:4 - 20:100:5 - 10.

5. The preparation method of the molecular-driven assembled M@SiO2 hollow composite microspheres according to claim 1, wherein, In the ethanolamine - ethanol solution, the concentration of ethanolamine is 0.001 - 0.005 mol / L.

6. The preparation method of the molecular-driven assembled M@SiO2 hollow composite microspheres according to claim 1, characterized in that, The concentration of the solid microspheres in the ethanolamine - ethanol solution is 5 - 10 g / L.

7. The M@SiO2 hollow composite microspheres prepared by the preparation method according to any one of claims 1 - 6 by molecular - driven assembly.

8. A functionalized M@SiO2 hollow composite microsphere, obtained by functional modification of the M@SiO2 hollow composite microsphere prepared by molecular - driven assembly according to claim 7, and the modification method is as follows: Disperse the M@SiO2 hollow composite microspheres in dichloromethane, and while ultrasonically treating at room temperature, dropwise add a dichloromethane solution of chlorosulfonic acid drop by drop, react for 20 - 60 min, then centrifuge, wash, and vacuum dry to obtain the functionalized M@SiO2 hollow composite microspheres; The concentration of the M@SiO2 hollow composite microspheres in dichloromethane is 20 - 50 g / L; The concentration of the dichloromethane solution of chlorosulfonic acid is 0.001 - 0.005 mol / L; The feeding ratio of chlorosulfonic acid to the M@SiO2 hollow composite microspheres is 0.01 - 0.05:1, mmol / g.

9. The application of the M@SiO2 hollow composite microspheres prepared by molecular - driven assembly according to claim 7, or the functionalized M@SiO2 hollow composite microspheres according to claim 8 as a heterogeneous catalyst in the field of catalytic oxidation.

10. The application according to claim 9, wherein For catalyzing the photocatalytic degradation of H2O2 active dyes.

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