Supported high-porosity porous metal oxide material and preparation method thereof

Abstract

The invention discloses a supported high-porosity porous metal oxide material and a preparation method thereof, and belongs to the field of advanced functional materials and nanotechnologies, the material is prepared through a template method, modified silicon dioxide is adopted as a template agent, an organic polymer and a metal oxide precursor are combined, and the supported high-porosity porous metal oxide material is prepared through a series of chemical reactions and treatment steps. And finally, a porous structure with high porosity and high specific surface area is formed. Compared with the prior art, the mass transfer efficiency and catalytic performance of the material are remarkably improved, operation is easy, raw materials are easy to obtain, the method is suitable for large-scale industrial production, and the prepared material shows excellent performance in the fields of gas sensing, heterogeneous catalysis and the like and has wide application prospects.

Description

Technical Field

[0001] The present invention relates to the field of advanced functional materials and nanotechnology, and particularly to a supported high-porosity porous metal oxide material and a preparation method thereof. Background Art

[0002] In the field of advanced functional materials and nanotechnology, supported high-porosity porous metal oxide materials have attracted much attention due to their wide applications in gas sensing, heterogeneous catalysis, adsorption and other fields. These materials are usually prepared by the template method, in which silicon dioxide (SiO 2 ) is often used as the main component of the template agent due to its high specific surface area and good chemical stability. However, in the prior art, the microporous structure formed by silicon dioxide in the template agent is difficult to form three-dimensional interconnected pore channels during the subsequent alkaline etching process, which results in a low mass transfer efficiency of the material. The non-connectivity of the microporous structure makes it difficult for gas or liquid molecules to rapidly diffuse to the active sites inside the material, thereby reducing the mass transfer efficiency of the material. This limitation is manifested as an extended response time and a decreased detection sensitivity in gas sensing applications; in catalytic applications, it is manifested as the difficulty for reactants to quickly reach the active sites, thereby reducing the catalytic efficiency. In addition, the microporous structure formed by silicon dioxide in the prior art is prone to collapse or blockage during the alkaline etching process, resulting in a limited specific surface area of the final material, further restricting the adsorption capacity and catalytic activity of the material. At the same time, this instability not only affects the mechanical properties of the material, but may also lead to a decline in the performance of the material during long-term use. Therefore, although the prior art can form a certain pore structure when preparing high-porosity porous metal oxide materials, there are still deficiencies in terms of mass transfer efficiency and structural stability, and further improvement is needed to enhance the performance of the material.

[0003] Chinese Patent CN110143608A discloses a preparation technology and application of a supported high-porosity porous metal oxide material, which belongs to the field of advanced functional materials and nanotechnology. Specifically, this method first combines a pre-hydrolyzed silicon oxide oligomer solution with a mixed solution of metal salts and loadings. After uniformly mixing the solution by stirring, the solvent is evaporated to obtain a metal hydroxide solid uniformly doped with silicon oxide oligomers. Subsequently, the metal oxide is crystallized by calcination, and then the silicon oxide is etched and removed using an alkaline solution to form a pore structure, finally obtaining a supported porous metal oxide material with high porosity. This material has a crystalline metal oxide framework, a relatively high specific surface area and porosity, and a three-dimensional interconnected hierarchical pore structure, and these characteristics enable it to exhibit excellent performance in fields such as gas sensing and heterogeneous catalysis. This preparation method is simple to operate, and the raw materials used are easy to obtain, which is suitable for large-scale industrial production. However, there is still room for improvement in the specific surface area and catalytic effect of the porous metal oxide material prepared by this invention. Summary of the Invention

[0004] In order to solve the deficiencies in the prior art, the present invention aims to provide a supported highly porous metal oxide material and a preparation method thereof.

[0005] In order to achieve the above invention object, the present invention adopts the following technical solutions:

[0006] A preparation method of a supported highly porous metal oxide material, comprising the following steps:

[0007] Step 1, preparation of the template agent: Mix an organic polymer and modified silica, add a solvent and stir evenly to form a mixed solution, and heat and stir to form a hybrid template agent;

[0008] Step 2, preparation of the metal oxide precursor solution: Dissolve the metal oxide precursor in a solvent, add hydrochloric acid and stir evenly, then add the sensitizing material precursor and stir until completely dissolved;

[0009] Step 3, preparation of the composite material: Mix the hybrid template agent and the precursor solution, stir evenly, coat it on an aluminum nitride ceramic substrate by spin coating, control the coating thickness, and dry to obtain the composite material;

[0010] Step 4, calcination treatment: Calcinate the composite material in a nitrogen atmosphere, controlling the temperature, heating rate and holding time;

[0011] Step 5, removal of the template agent: Add the metal oxide to an aqueous sodium hydroxide solution, react and remove the template agent by etching with an alkaline solution, and dry after centrifugal separation to obtain the supported highly porous metal oxide material.

[0012] Preferably, the preparation method of the supported highly porous metal oxide material is as follows, by weight:

[0013] Step 1, preparation of the template agent: Mix 8-12 parts of an organic polymer and 20-40 parts of modified silica, add 150-250 parts of a solvent and stir evenly to form a uniformly dispersed mixed solution, and heat and stir the mixed solution at 60-80 °C for 2-4 hours to form a hybrid template agent;

[0014] Step 2, preparation of the metal oxide precursor solution: Dissolve 35-65 parts of the metal oxide precursor in 400-600 parts of a solvent, add 4-8 parts of hydrochloric acid and stir evenly, add 1-3 parts of the sensitizing material precursor to the solution and stir until completely dissolved to form a uniform precursor solution;

[0015] Step 3: Preparation of composite material: Mix 80 - 120 parts of the hybrid template prepared in Step 1 with 300 - 500 parts of the precursor solution prepared in Step 2, stir evenly, and coat it on the aluminum nitride ceramic substrate by spin coating. Control the coating thickness to be 40 - 60 microns. Place the coated substrate in an oven and dry it at 45 - 55°C for 2 - 5 hours to completely volatilize the solvent, obtaining the composite material;

[0016] Step 4: Calcination treatment: Place the composite material prepared in Step 3 in a muffle furnace and calcine it under a nitrogen atmosphere. The calcination temperature is 400 - 600°C, the heating rate is 1 - 5°C / min, and the holding time is 2 - 5 hours to obtain the metal oxide;

[0017] Step 5: Removal of template agent: Add the metal oxide prepared in Step 4 to 400 - 600 parts of sodium hydroxide aqueous solution with pH = 8 - 14, react at 60 - 80°C for 2 - 6 hours, and etch and remove the hybrid template agent through the alkaline solution. After the reaction, obtain the porous metal oxide material by centrifugal separation, wash it with water 1 - 5 times, and dry it to obtain the supported high-porosity porous metal oxide material.

[0018] The organic polymer is at least one of polystyrene and polyvinyl alcohol.

[0019] The metal oxide precursor is at least one of tin tetrachloride, zinc nitrate, and iron nitrate.

[0020] The sensitizing material precursor is at least one of gold chloride, platinum tetrachloride, and lanthanum nitrate.

[0021] The solvent is at least one of water, ethanol, methanol, acetone, and tetrahydrofuran.

[0022] The preparation method of the modified silica is as follows:

[0023] S1: Mix silica with oxalyl chloride, add N,N-dimethylformamide and dichloromethane, heat and stir, then cool and quench, and concentrate and dry under reduced pressure to obtain the pretreatment product;

[0024] S2: Under nitrogen protection, mix the ketone compound with the pretreatment product, add absolute ethanol and 4-dimethylaminopyridine, heat and stir, then filter and separate, and concentrate and dry under reduced pressure to obtain the post-treatment product;

[0025] S3: Mix the post-treatment product with the amine compound, add methanol and 4-dimethylaminopyridine, heat and stir, then filter to obtain the modified silica.

[0026] Preferably, the preparation method of the modified silica is as follows, in parts by weight:

[0027] S1. Mix 30 - 50 parts of silica with 300 - 400 parts of oxalyl chloride, then add 3 - 5 parts of N,N - dimethylformamide, add 800 - 1200 parts of dichloromethane, heat the mixture to 50 - 60 °C, and continuously stir at this temperature for 2 - 6 hours. Subsequently, cool the reaction system to room temperature, conduct quenching treatment, and finally obtain a pretreated product through concentration and drying under reduced pressure;

[0028] S2. Under a nitrogen - protected environment, mix 15 - 25 parts of a ketone - containing compound with the pretreated product prepared in step S1, add 500 - 700 parts of absolute ethanol as a dispersion medium, add 25 - 35 parts of 4 - dimethylaminopyridine to the system, heat to 40 - 60 °C, maintain constant - temperature stirring for 5 - 15 hours. After the reaction is completed, separate the product by filtration and conduct concentration and drying under reduced pressure to obtain a post - treated product;

[0029] S3. Mix the post - treated product obtained in step S2 with 8 - 12 parts of an amine - containing compound, add 200 - 300 parts of methanol, then add 8 - 12 parts of 4 - dimethylaminopyridine, heat the mixture to 60 - 80 °C, and continuously stir at this temperature for 2 - 8 hours. After stirring, conduct filtration to obtain modified silica.

[0030] The ketone - containing compound is at least one of 4 - hydroxy - 4 - methyl - 2 - pentanone, 4,5 - dihydroxy - 2,3 - pentanedione, and 3 - hydroxycyclobutanone.

[0031] The amine - containing compound is at least one of 1,5,5 - trimethyl - 2 - cyclohexene - 1 - methylamine, 3 - aminobicyclo[2.2.1]hept - 5 - ene - 2 - carboxamide, and 2 - (methoxymethyl)benzene - 1,4 - diamine.

[0032] In the preparation method of the modified silica, the functions of each substance are as follows:

[0033] Silica itself has a high specific surface area and good chemical stability, and is the core material in the modification process. It provides a stable surface for subsequent chemical reactions, facilitating the grafting and modification of other substances.

[0034] Oxalyl chloride reacts with the hydroxyl groups on the surface of silica to form acyl chloride groups, providing active sites for subsequent chemical reactions. Oxalyl chloride has strong reactivity and can efficiently convert hydroxyl groups into acyl chloride groups, improving the reaction efficiency.

[0035] N,N - dimethylformamide accelerates the reaction of oxalyl chloride with the hydroxyl groups on the silica surface.

[0036] Dichloromethane serves as a solvent, providing a reaction medium.

[0037] The keto - containing compound reacts with the acyl chloride groups on the surface of the acylated silica to form stable chemical bonds. Microporous and mesoporous structures are formed, increasing the specific surface area of the material.

[0038] 4 - Dimethylaminopyridine neutralizes the reaction by - products, increasing the reaction rate.

[0039] Ethanol acts as a dispersion medium, providing a reaction environment.

[0040] The amine - containing compound acts as the final modifier, reacting with the post - treated product to introduce specific chemical groups. Three - dimensional interconnected pores are formed, improving the mass transfer efficiency of the material.

[0041] Methanol acts as a solvent, providing a reaction medium.

[0042] In the preparation process of the modified silica, various substances act synergistically. Through a series of chemical reactions, specific chemical groups are gradually introduced. These modified silicas significantly improve the porosity, specific surface area, and catalytic performance of the material in the subsequent preparation of supported porous metal oxide materials.

[0043] Compared with the prior art, it has the following beneficial effects:

[0044] 1) By optimizing the preparation process of the template agent and the metal oxide precursor and combining with specific modified silica, the supported high - porosity porous metal oxide material prepared by the present invention has a higher specific surface area. A high specific surface area means more active sites, providing more adsorption and reaction sites for target molecules such as gases and liquids, thus significantly improving the adsorption performance and catalytic efficiency of the material.

[0045] 2) By introducing sensitizing materials such as platinum tetrachloride into the metal oxide precursor solution, the catalytic performance of the material is further improved. The introduction of modified silica also significantly enhances the pore structure of the material, enabling it to form three - dimensional interconnected pores during the subsequent alkaline etching process. These interconnected pores greatly improve the mass transfer efficiency of the material, allowing target molecules to diffuse more quickly to the active sites inside the material, thus significantly enhancing the catalytic performance of the material.

[0046] 3) By precisely controlling the reaction conditions (such as temperature, stirring time, and solvent selection) during the preparation process, a uniformly dispersed hybrid template agent can be formed. Finally, the template agent is removed by alkaline solution etching to form a porous structure with three - dimensional interconnected pores. This optimized pore structure not only increases the specific surface area of the material but also enhances its adsorption capacity and catalytic activity, giving it excellent application prospects in fields such as gas sensing and heterogeneous catalysis. Detailed implementation mode

[0047] Main sources of substances:

[0048] Polyvinyl alcohol, model: 117, brand: Kuraray, origin: Japan.

[0049] Silica, specification: DM-20S, particle size: 12 nm, manufacturer (origin): Tokuyama, Japan.

[0050] 3-Aminobicyclo[2.2.1]hept-5-ene-2-carboxamide, CAS No.: 402846-45-1, molecular formula: C 8 H 12 N 2 O.

[0051] 2-(Methoxymethyl)benzene-1,4-diamine, CAS No.: 337906-36-2, molecular formula: C 8 H 12 N 2 O.

[0052] 1,5,5-Trimethyl-2-cyclohexene-1-methanamine, CAS No.: 252921-81-6, molecular formula: C 10 H 19 N.

[0053] The remaining raw materials in the examples and comparative examples of the present invention are all commercially available products.

[0054] The design concept of the present invention is to prepare a supported porous metal oxide material with high porosity and high specific surface area by optimizing the preparation process of the template agent and the metal oxide precursor, combined with specific modified silica. By selecting appropriate organic polymers and modified silica, and precisely controlling the reaction conditions (such as temperature, stirring time, and solvent selection) in the preparation process, a uniformly dispersed hybrid template agent can be formed. In addition, by introducing a sensitizing material such as platinum tetrachloride into the metal oxide precursor solution, the catalytic performance of the material can be further improved. Finally, the template agent is removed by etching with an alkaline solution to form a porous structure with three-dimensional interconnected pores, thereby significantly enhancing the adsorption and catalytic performance of the material, making it have excellent application prospects in the fields of gas sensing, heterogeneous catalysis, etc.

[0055] Example 1

[0056] A preparation method of a supported high-porosity porous metal oxide material is as follows:

[0057] Step 1. Preparation of the template agent: Mix 10 g of polyvinyl alcohol with 30 g of modified silica, add 200 g of water and stir evenly to form a uniformly dispersed mixed solution. Heat and stir the mixed solution at 70 °C for 3 hours to form a hybrid template agent;

[0058] Step 2: Preparation of metal oxide precursor solution: Dissolve 30 g of tin tetrachloride and 20 g of iron nitrate in 500 g of absolute ethanol, add 6 g of 37 wt% hydrochloric acid, stir evenly, add 2 g of platinum tetrachloride to the solution, and stir until completely dissolved to form a uniform precursor solution;

[0059] Step 3: Preparation of composite material: Mix 100 g of the hybrid template agent prepared in Step 1 with 400 g of the precursor solution prepared in Step 2, stir evenly, and coat it on the aluminum nitride ceramic substrate by spin coating, controlling the coating thickness to be 50 microns. Place the coated substrate in a drying oven and dry it at 50 °C for 3 hours to completely volatilize the solvent to obtain a composite material;

[0060] Step 4: Calcination treatment: Place the composite material prepared in Step 3 in a muffle furnace and calcine it under a nitrogen atmosphere. The calcination temperature is 450 °C, the heating rate is 3 °C / min, and the holding time is 3 hours to obtain a metal oxide;

[0061] Step 5: Removal of template agent: Add the metal oxide prepared in Step 4 to 500 g of sodium hydroxide aqueous solution with pH = 12, react at 75 °C for 4 hours, etch and remove the hybrid template agent through the alkaline solution. After the reaction, obtain a porous metal oxide material by centrifugal separation, wash it 5 times with deionized water, and dry it to obtain a supported high-porosity porous metal oxide material.

[0062] The preparation method of the modified silica is as follows:

[0063] S1: Mix 40 g of silica with 320 g of oxalyl chloride, add 4 g of N,N-dimethylformamide, add 1000 g of dichloromethane, heat the mixture to 55 °C, and continuously stir at this temperature for 4 hours. Subsequently, cool the reaction system to room temperature, perform quenching treatment, and finally obtain a pretreatment product through reduced pressure concentration and drying;

[0064] S2: Under a nitrogen-protected environment, mix 20 g of 3-hydroxycyclobutanone with the pretreatment product prepared in Step S1, add 600 g of absolute ethanol as a dispersion medium, add 30 g of 4-dimethylaminopyridine to the system, heat to 50 °C, and keep stirring at a constant temperature for 10 hours. After the reaction is completed, separate the product by filtration and perform reduced pressure concentration and drying to obtain a post-treatment product;

[0065] S3: Mix the post-treatment product obtained in Step S2 with 10 g of 3-aminobicyclo[2.2.1]hept-5-ene-2-carboxamide, add 250 g of methanol, then add 10 g of 4-dimethylaminopyridine, heat the mixture to 70 °C, and keep stirring at a constant temperature at this temperature for 5 hours. After the stirring is completed, perform filtration to obtain the modified silica.

[0066] Example 2

[0067] The preparation method of a supported highly porous metal oxide material is basically the same as that of Example 1, and the only difference is the different preparation method of the modified silica.

[0068] The preparation method of the modified silica is as follows:

[0069] S1. Mix 40 g of silica with 320 g of oxalyl chloride, then add 4 g of N,N-dimethylformamide, add 1000 g of dichloromethane, heat the mixture to 55 °C, and continuously stir at this temperature for 4 hours. Subsequently, cool the reaction system to room temperature, carry out quenching treatment, and finally obtain a pretreatment product by concentration under reduced pressure and drying;

[0070] S2. Under a nitrogen-protected environment, mix 20 g of 4,5-dihydroxy-2,3-pentanedione with the pretreatment product obtained in step S1, add 600 g of absolute ethanol as a dispersion medium, add 30 g of 4-dimethylaminopyridine to the system, heat to 50 °C, and keep stirring at a constant temperature for 10 hours. After the reaction is completed, separate the product by filtration and carry out concentration under reduced pressure and drying to obtain a post-treatment product;

[0071] S3. Mix the post-treatment product obtained in step S2 with 10 g of 3-aminobicyclo[2.2.1]hept-5-ene-2-carboxamide, add 250 g of methanol, then add 10 g of 4-dimethylaminopyridine, heat the mixture to 70 °C, and stir at a constant temperature at this temperature for 5 hours. After the stirring is completed, filter to obtain the modified silica.

[0072] Example 3

[0073] The preparation method of a supported highly porous metal oxide material is basically the same as that of Example 1, and the only difference is the different preparation method of the modified silica.

[0074] The preparation method of the modified silica is as follows:

[0075] S1. Mix 40 g of silica with 320 g of oxalyl chloride, then add 4 g of N,N-dimethylformamide, add 1000 g of dichloromethane, heat the mixture to 55 °C, and continuously stir at this temperature for 4 hours. Subsequently, cool the reaction system to room temperature, carry out quenching treatment, and finally obtain a pretreatment product by concentration under reduced pressure and drying;

[0076] S2. Under a nitrogen-protected environment, mix 20 g of 4-hydroxy-4-methyl-2-pentanone with the pretreatment product obtained in step S1, add 600 g of absolute ethanol as a dispersion medium, add 30 g of 4-dimethylaminopyridine to the system, heat to 50 °C, maintain constant temperature and stir for 10 hours. After the reaction is completed, separate the product by filtration and perform concentration under reduced pressure and drying to obtain the post-treatment product;

[0077] S3. Mix the post-treatment product obtained in step S2 with 10 g of 3-aminobicyclo[2.2.1]hept-5-en-2-carboxamide, add 250 g of methanol, then add 10 g of 4-dimethylaminopyridine, heat the mixture to 70 °C, maintain constant temperature and stir at this temperature for 5 hours. After stirring is completed, filter to obtain the modified silica.

[0078] Example 4

[0079] The preparation method of a supported high-porosity porous metal oxide material is basically the same as that of Example 1, and the only difference is the different preparation method of the modified silica.

[0080] The preparation method of the modified silica is as follows:

[0081] S1. Mix 40 g of silica with 320 g of oxalyl chloride, add 4 g of N,N-dimethylformamide, add 1000 g of dichloromethane, heat the mixture to 55 °C, and continuously stir at this temperature for 4 hours. Subsequently, cool the reaction system to room temperature, perform quenching treatment, and finally perform concentration under reduced pressure and drying to obtain the pretreatment product;

[0082] S2. Under a nitrogen-protected environment, mix 20 g of 3-hydroxycyclobutanone with the pretreatment product obtained in step S1, add 600 g of absolute ethanol as a dispersion medium, add 30 g of 4-dimethylaminopyridine to the system, heat to 50 °C, maintain constant temperature and stir for 10 hours. After the reaction is completed, separate the product by filtration and perform concentration under reduced pressure and drying to obtain the post-treatment product;

[0083] S3. Mix the post-treatment product obtained in step S2 with 10 g of 1,5,5-trimethyl-2-cyclohexene-1-methanamine, add 250 g of methanol, then add 10 g of 4-dimethylaminopyridine, heat the mixture to 70 °C, maintain constant temperature and stir at this temperature for 5 hours. After stirring is completed, filter to obtain the modified silica.

[0084] Example 5

[0085] The preparation method of a supported high-porosity porous metal oxide material is basically the same as that of Example 1, and the only difference is the different preparation method of the modified silica.

[0086] The preparation method of the modified silica is as follows:

[0087] S1. Mix 40 g of silica with 320 g of oxalyl chloride, then add 4 g of N,N-dimethylformamide, add 1000 g of dichloromethane, heat the mixture to 55 °C, and continuously stir at this temperature for 4 hours. Subsequently, cool the reaction system to room temperature, carry out quenching treatment, and finally obtain a pretreatment product through concentration and drying under reduced pressure;

[0088] S2. Under the protection of nitrogen, mix 20 g of 3-hydroxycyclobutanone with the pretreatment product obtained in step S1, add 600 g of absolute ethanol as a dispersion medium, add 30 g of 4-dimethylaminopyridine to the system, heat to 50 °C, and keep stirring at a constant temperature for 10 hours. After the reaction is completed, separate the product by filtration and carry out concentration and drying under reduced pressure to obtain a post-treatment product;

[0089] S3. Mix the post-treatment product obtained in step S2 with 10 g of 2-(methoxymethyl)benzene-1,4-diamine, add 250 g of methanol, then add 10 g of 4-dimethylaminopyridine, heat the mixture to 70 °C, and keep stirring at a constant temperature at this temperature for 5 hours. After the stirring ends, carry out filtration to obtain the modified silica.

[0090] Comparative Example 1

[0091] The preparation method of a supported highly porous metal oxide material is basically the same as that of Example 1, and the only difference is that the preparation method of the modified silica is different.

[0092] The preparation method of the modified silica is as follows:

[0093] S1. Mix 40 g of silica with 320 g of oxalyl chloride, then add 4 g of N,N-dimethylformamide, add 1000 g of dichloromethane, heat the mixture to 55 °C, and continuously stir at this temperature for 4 hours. Subsequently, cool the reaction system to room temperature, carry out quenching treatment, and finally obtain a pretreatment product through concentration and drying under reduced pressure;

[0094] S2. Under the protection of nitrogen, mix 20 g of 4-hydroxy-2-butanone with the pretreatment product obtained in step S1, add 600 g of absolute ethanol as a dispersion medium, add 30 g of 4-dimethylaminopyridine to the system, heat to 50 °C, and keep stirring at a constant temperature for 10 hours. After the reaction is completed, separate the product by filtration and carry out concentration and drying under reduced pressure to obtain a post-treatment product;

[0095] S3. Mix the post-treatment product obtained in step S2 with 10 g of 3-aminobicyclo[2.2.1]hept-5-ene-2-carboxamide, add 250 g of methanol, then add 10 g of 4-dimethylaminopyridine, heat the mixture to 70 °C, stir at this temperature for 5 hours, and after the stirring is completed, filter to obtain modified silica.

[0096] Comparative Example 2

[0097] A preparation method of a supported high-porosity porous metal oxide material is basically the same as that of Example 1, and the only difference is that the preparation method of the modified silica is different.

[0098] The preparation method of the modified silica is as follows:

[0099] S1. Mix 40 g of silica with 320 g of oxalyl chloride, add 4 g of N,N-dimethylformamide, add 1000 g of dichloromethane, heat the mixture to 55 °C, and continuously stir at this temperature for 4 hours. Then, cool the reaction system to room temperature, perform quenching treatment, and finally dry by vacuum concentration to obtain a pretreatment product;

[0100] S2. Under a nitrogen-protected environment, mix 20 g of 3-hydroxycyclobutanone with the pretreatment product prepared in step S1, add 600 g of absolute ethanol as a dispersion medium, add 30 g of 4-dimethylaminopyridine to the system, heat to 50 °C, and keep stirring at a constant temperature for 10 hours. After the reaction is completed, separate the product by filtration and perform vacuum concentration and drying to obtain a post-treatment product;

[0101] S3. Mix the post-treatment product obtained in step S2 with 10 g of 5-norbornene-2-methylamine, add 250 g of methanol, then add 10 g of 4-dimethylaminopyridine, heat the mixture to 70 °C, stir at this temperature for 5 hours, and after the stirring is completed, filter to obtain modified silica.

[0102] Comparative Example 3

[0103] A preparation method of a supported high-porosity porous metal oxide material is basically the same as that of Example 1, and the only difference is that the modified silica is replaced with an equal amount of silica.

[0104] Test Example 1

[0105] Specific surface area test

[0106] The specific surface areas of the supported high-porosity porous metal oxide materials of the examples and comparative examples were respectively tested (BET, determined by nitrogen adsorption method). The test results are shown in Table 1.

[0107] Table 1

[0108] Experimental Scheme <![CDATA[Specific surface area (m 2 / g)]]> Example 1 345 Example 2 337 Example 3 331 Example 4 339 Example 5 344 Comparative Example 1 327 Comparative Example 2 321 Comparative Example 3 295

[0109] Test Example 2

[0110] Catalytic decomposition efficiency test

[0111] Experimental method

[0112] Sample preparation: Take 2 g of the supported high-porosity porous metal oxide materials of the examples and comparative examples of the present invention and place them on the sintered cores in glass tubes with a diameter of 5 mm respectively.

[0113] Experimental apparatus: The bottom of the glass tube is connected to a formaldehyde generator, and the top is connected to an on-line detector of a gas chromatograph. Air is blown into the formaldehyde generator by a pump and mixed with formaldehyde to obtain air with a formaldehyde concentration of 220 ppm.

[0114] Experimental process: The air containing formaldehyde enters from the bottom of the glass tube, passes through the glass tube filled with the porous metal oxide material, and then enters the gas chromatograph from the top for on-line detection.

[0115] Detect the content of formaldehyde by a gas chromatograph to obtain the catalytic decomposition efficiency.

[0116] The test results are shown in Table 2.

[0117] Table 2

[0118] Experimental Scheme Catalytic decomposition efficiency / % Example 1 95.4 Example 2 93.6 Example 3 93.2 Example 4 94.1 Example 5 98.7 Comparative Example 1 90.2 Comparative Example 2 89.6 Comparative Example 3 83.5

[0119] It can be seen from the test results that the specific surface area of the supported high-porosity porous metal oxide material prepared in Example 1 of the present invention is the largest, and Example 5 has better results in the catalytic decomposition efficiency test.

[0120] Compared with the different hydroxy compounds used in other examples and comparative examples, 3-hydroxycyclobutanone used in Example 1 of the present invention exhibits more excellent specific surface area and catalytic effect. This is mainly attributed to the unique cyclic structure and chemical properties of 3-hydroxycyclobutanone. When 3-hydroxycyclobutanone with a cyclic structure reacts with the acyl chloride groups on the silica surface, it can be more effectively unfolded and cover the silica surface, increasing the contact area with the silica surface, thereby forming more micropores and mesoporous structures. These micropores and mesopores are retained during the subsequent calcination process, significantly increasing the specific surface area of the final material. A high specific surface area means more active sites, providing more adsorption and reaction sites for target molecules such as formaldehyde, thus improving the catalytic decomposition efficiency.

[0121] In Example 1 of the present invention, 3-aminobicyclo[2.2.1]hept-5-ene-2-carboxamide has better specific surface area and catalytic effect compared with 1,5,5-trimethylcyclohex-2-en-1-ylamine used in Example 4 and 5-norbornene-2-methylamine used in Comparative Example 2. This is mainly attributed to the chemical structure characteristics of 3-aminobicyclo[2.2.1]hept-5-ene-2-carboxamide. This compound contains two amino groups, which can provide more active sites during the reaction, promote chemical bonding with modified silica, and thus form a more uniform and stable pore structure. This structure not only increases the specific surface area of the material but also enhances its adsorption capacity and catalytic activity.

[0122] 2-(Methoxymethyl)benzene-1,4-diamine used in Example 5 contains a benzene ring, and thus forms more effective three-dimensional interconnected pores during alkaline etching compared with Example 1, significantly improving the mass transfer efficiency, enabling molecules such as formaldehyde to quickly diffuse to the active sites, enhancing the adsorption and catalytic performance, and thus showing better performance in the catalytic decomposition of formaldehyde.

Claims

1. A method for preparing a supported high-porosity porous metal oxide material, characterized in that: The following steps are involved: Step 1, preparation of template: mixing organic polymer and modified silica, adding solvent and stirring evenly to form a mixed solution, heating and stirring to form a hybrid template; Step 2, preparation of metal oxide precursor solution: dissolving the metal oxide precursor in a solvent, adding hydrochloric acid, stirring evenly, then adding the sensitizing material precursor, stirring until completely dissolved; Step 3, preparation of composite materials: mixing the hybrid template agent with the precursor solution, stirring evenly, coating on the aluminum nitride ceramic substrate by spin coating, controlling the coating thickness, and drying to obtain the composite material; Step 4, calcination treatment: calcining the composite material in a nitrogen atmosphere, controlling the temperature, heating rate and holding time; Step 5, removing the template: adding the metal oxide to a sodium hydroxide aqueous solution, removing the template by etching with an alkaline solution after the reaction, centrifuging and drying to obtain a supported high-porosity porous metal oxide material; The preparation method of the modified silicon dioxide is as follows: S1, mixing silica with oxalyl chloride, adding N,N-dimethylformamide and dichloromethane, heating and stirring, cooling and quenching, concentrating and drying under reduced pressure to obtain a pretreated product; S2. Under nitrogen protection, the ketone-containing compound is mixed with the pre-treated product, anhydrous ethanol and 4-dimethylaminopyridine are added, the mixture is heated and stirred, and then filtered and separated, and the mixture is concentrated and dried under reduced pressure to obtain a post-treated product; S3, mixing the post-treated product with an amine compound, adding methanol and 4-dimethylaminopyridine, heating and stirring, and then filtering to obtain modified silicon dioxide.

2. The method for preparing a supported high-porosity porous metal oxide material according to claim 1, characterized in that: The preparation method is as follows, in parts by weight: Step 1, preparation of the template: 8 to 12 parts of an organic polymer and 20 to 40 parts of modified silica are mixed, 150 to 250 parts of a solvent are added and stirred evenly to form a uniformly dispersed mixed solution, and the mixed solution is heated and stirred at 60 to 80° C. for 2 to 4 hours to form a hybrid template; Step 2, preparation of metal oxide precursor solution: dissolve 35-65 parts of metal oxide precursor in 400-600 parts of solvent, add 4-8 parts of hydrochloric acid, stir evenly, add 1-3 parts of sensitizing material precursor to the solution, stir until completely dissolved, and form a uniform precursor solution; Step 3, preparation of a composite material: 80 to 120 parts of the hybrid template prepared in step 1 are mixed with 300 to 500 parts of the precursor solution prepared in step 2, stirred evenly, and then coated on an aluminum nitride ceramic substrate by spin coating, with the coating thickness controlled to be 40 to 60 microns, and the coated substrate is placed in a drying oven and dried at 45 to 55° C. for 2 to 5 hours to completely volatilize the solvent to obtain a composite material; Step 4, calcination treatment: placing the composite material prepared in step 3 in a muffle furnace, calcining it in a nitrogen atmosphere, the calcination temperature is 400-600° C., the heating rate is 1-5° C. / min, and the holding time is 2-5 hours to obtain a metal oxide; Step 5, removal of the template: add the metal oxide prepared in step 4 to 400-600 parts of a sodium hydroxide aqueous solution with a pH of 8-14, react at 60-80°C for 2-6 hours, remove the hybrid template by etching with an alkaline solution, and after the reaction, obtain a porous metal oxide material by centrifugal separation, wash with water 1-5 times, and obtain a supported high-porosity porous metal oxide material after drying.

3. The method for preparing a supported high-porosity porous metal oxide material according to claim 1 or 2, characterized in that: The organic polymer is at least one of polystyrene and polyvinyl alcohol.

4. The method for preparing a supported high-porosity porous metal oxide material according to claim 1 or 2, characterized in that: The metal oxide precursor is at least one of tin tetrachloride, zinc nitrate and ferric nitrate.

5. The method for preparing a supported high-porosity porous metal oxide material according to claim 1 or 2, characterized in that: The sensitizing material precursor is at least one of gold chloride, platinum tetrachloride and lanthanum nitrate.

6. The method for preparing a supported high-porosity porous metal oxide material according to claim 1 or 2, characterized in that: The solvent is at least one of water, ethanol, methanol, acetone and tetrahydrofuran.

7. The method for preparing a supported high-porosity porous metal oxide material according to claim 1 or 2, characterized in that: The preparation method of the modified silicon dioxide is as follows, in parts by weight: S1, 30-50 parts of silicon dioxide and 300-400 parts of oxalyl chloride are mixed, and then 3-5 parts of N,N-dimethylformamide and 800-1200 parts of dichloromethane are added, the mixture is heated to 50-60°C, and stirred at the temperature for 2-6 hours, then the reaction system is cooled to room temperature, quenched, and finally concentrated and dried under reduced pressure to obtain a pretreated product; S2. In a nitrogen-protected environment, 15 to 25 parts of the ketone-containing compound are mixed with the pre-treated product obtained in step S1, 500 to 700 parts of anhydrous ethanol are added as a dispersion medium, 25 to 35 parts of 4-dimethylaminopyridine are added to the system, the temperature is raised to 40 to 60° C., and the temperature is maintained at a constant temperature for 5 to 15 hours. After the reaction is completed, the product is separated by filtration, and concentrated and dried under reduced pressure to obtain a post-treated product; S3. Mix the post-treated product obtained in step S2 with 8 to 12 parts of an amine compound, add 200 to 300 parts of methanol, and then add 8 to 12 parts of 4-dimethylaminopyridine, heat the mixture to 60 to 80° C., stir at this temperature for 2 to 8 hours, and filter after stirring to obtain modified silicon dioxide.

8. The method for preparing a supported high-porosity porous metal oxide material according to claim 1 or 7, characterized in that: The ketone-containing compound is at least one of 4-hydroxy-4-methyl-2-pentanone, 4,5-dihydroxy-2,3-pentanedione, and 3-hydroxycyclobutanone.

9. The method for preparing a supported high-porosity porous metal oxide material according to claim 1 or 7, characterized in that: The amine compound is at least one of 1,5,5-trimethyl-2-cyclohexene-1-methylamine, 3-aminobicyclo[2.2.1]hept-5-ene-2-carboxamide, and 2-(methoxymethyl)benzene-1,4-diamine.

10. A supported high-porosity porous metal oxide material, characterized in that: The preparation method is as described in any one of claims 1 to 9.