Millimeter-sized catalytic material with hollow spherical structure multi-active component loading sites and preparation method thereof

Abstract

The application discloses a kind of millimeter level catalytic material with hollow spherical structure multi-active component loading site and preparation method thereof, the oil phase containing molecular sieve material and the water phase containing aluminum sol are formed using coaxial double-dropper forming device, and the gel ball of oil-in-water structure is obtained in situ, and after aging, calcination, the hollow spherical alumina carrier MS@Al2O3 containing molecular sieve material is obtained.The soluble salt of metal oxide is loaded on the surface and pore of carrier by one-step vacuum-spraying method, and then the surface-loaded metal soluble salt is oxidized into metal oxide by gas phase oxidation, to obtain catalytic material MOx / MS@Al2O3.The catalytic material has physical partition site, and different active components are loaded inside and outside the hollow carrier.The catalyst is suitable for industrial series reaction.

Description

Technical Field

[0001] This invention belongs to the field of catalytic materials, specifically a millimeter-scale catalytic material with a hollow spherical structure and multiple active component loading sites, and its preparation method. This material has multiple active component loading sites, which can achieve spatial separation of active components. Background Technology

[0002] With the acceleration of global industrialization, the demand for resources has multiplied. However, for non-renewable resources, primarily fossil fuels, efficient utilization has become a key focus. Catalysts, due to their ability to increase reaction rates and reduce energy consumption, enable efficient resource utilization and thus occupy an extremely important position in modern chemical industry. Catalyst materials of different shapes have different specific surface areas, pore sizes, and particle sizes, often resulting in different catalytic properties and application areas. Hollow spherical catalyst materials, due to their unique cavity structure, flexible active component loading sites, and excellent small molecule species adsorption capacity, have received widespread attention in recent years.

[0003] Hollow spherical catalysts utilize a cavity and shell structure as their framework. The hollow cavities create a concentration gradient for reactants, promoting diffusion and facilitating contact between reactant molecules and active sites. Reference Nat. Mater., 2022, 21, 572-579, describes the preparation of a catalyst with metal oxides loaded within a hollow molecular sieve shell, and evaluates its performance in the Fischer-Tropsch gas-to-gasoline synthesis reaction. The results show that the stronger hydrogen adsorption capacity within the cavity creates a concentration gradient between the reactant molecules outside the catalyst and inside the hollow cavity, promoting reactant diffusion into the cavity and improving the catalyst's hydrogenation efficiency and CO conversion rate.

[0004] The inner surface of the cavity, the pore space, and the outer surface of the shell of hollow spherical catalytic materials can all serve as loading sites for active species, providing ample and selectable loading sites for active components. Therefore, the flexible loading characteristic of the hollow structure allows for the loading of multiple active sites, and spatial separation avoids mutual interference between active components. The literature ACS Catal., 2017, 7, 7509-7519 reports a hollow nanocatalytic material with different active components loaded on the outer surface of the shell and the pore space. In this hollow nanoreactor, the carbon dioxide hydrogenation reaction proceeds through a series reaction. First, carbon dioxide undergoes reverse water vapor conversion at Pt sites on the outer surface of the catalyst to generate CO. Then, CO enters the hollow cavity of the catalyst and undergoes alkylation on the transition metal within the cavity to generate methane. Experiments show that the inner surface of the hollow structure adsorbs molecular hydrogen more strongly than the outer surface, and the adsorption strength increases accordingly with the increase of the inner cavity curvature. Furthermore, the thicker the shell and the longer the pore length, the longer the contact time between reactant molecules and the active center, resulting in a higher carbon dioxide conversion rate.

[0005] In summary, the hollow cavity structure of hollow spherical catalytic materials can induce the diffusion of reactant molecules and ensure sufficient contact with active sites by creating a concentration gradient. The flexible loading sites for active components can accommodate multiple active sites and spatially separate them, preventing mutual interference between active components. However, existing hollow spherical catalytic materials are generally at the micro-nano scale, making it difficult to meet the size, breakage strength, and other requirements of industrial applications, thus limiting their development to the laboratory stage. Therefore, this invention aims to develop a millimeter-scale catalytic material with a hollow spherical structure. Utilizing the flexible loading characteristic of active components, different active components are loaded inside and outside the hollow support. During application, the active components on the outer surface or in the pores of the catalyst undergo the first catalytic reaction, while the active components inside the catalyst cavity undergo the second catalytic reaction. The products of the first reaction serve as reactants in the second reaction, reducing reaction steps, energy consumption, and byproduct generation, saving reactant usage, and effectively improving the efficiency of the catalytic reaction. Summary of the Invention

[0006] The purpose of this invention is to provide a type of millimeter-scale catalytic material with a hollow spherical structure and multiple active component loading sites, and another purpose is to provide a method for preparing the catalytic material. The material has multiple active component loading sites, which can achieve spatial separation of active components.

[0007] The present invention provides a millimeter-scale catalytic material with a hollow spherical structure and multiple active component loading sites, denoted as MOx / MS@Al2O3. MS@Al2O3 is the support, consisting of spherical particles with a diameter of 2.5-4.0 mm. MS is encapsulated within an Al2O3 shell with a thickness of 0.5-1.5 mm and a pore size of 10-50 nm. MOx represents a metal oxide loaded on the surface of the MS@Al2O3 support, and MS represents a molecular sieve, which is any one of ZSM-5, HZSM-5, SAPO-34, and SBA-15. The mass ratio of MOx / MS is 0.5-3.5, the MS particle size is 2-100 μm, and the silicon-to-aluminum ratio is 25-30. MOx is one or two of SiO2, In2O3, Ga2O3, and ZnO. The MOx loading is between 7-15 wt%. The bulk density of the MOx / MS@Al2O3 catalytic material is 0.2-0.4 g / cm³. 3 The crushing strength is 10-20N, and the MOx loading is the mass percentage of MOx to the carrier MS@Al2O3.

[0008] The present invention provides a method for preparing millimeter-sized catalytic materials with hollow spherical structures and multiple active component loading sites. The method involves dispersing molecular sieve materials with particle sizes of 2-100 μm in an inner oil phase, using aluminum sol as the sol-aqueous phase, and preparing water-in-oil structured gel spheres using a coaxial double-droplet forming device. After curing via an oil column forming method, the spheres undergo aging and calcination to obtain hollow spherical alumina support MS@Al2O3 containing molecular sieve materials in situ. A metal salt solution of metal oxides is then impregnated onto the surface and pores of the support using a vacuum-spray method, followed by a gas-phase oxidation process to obtain the catalytic material. The competitive adsorption between different metal salt solutions allows different metal oxides to be loaded onto different sites on the support. The hollow spherical catalytic material prepared by this method can physically segment the loading sites and has an overall millimeter-sized structure, which can meet the requirements of industrial applications.

[0009] The method for preparing millimeter-scale catalytic materials with hollow spherical structures provided by this invention includes the following specific steps:

[0010] A. Preparation of the internal oil phase

[0011] Weigh out molecular sieve material with MS particle size of 2-100 μm and uniformly disperse it in an oily hydrophobic aqueous solution to prepare an internal oil phase with MS content of 0.15-0.25 g / mL.

[0012] The oleophobic aqueous solution is bromobenzene and liquid paraffin (C 42 H 70 O 35 ), bromocyclohexane (C6H) 11 Br), poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (C)290 H 582 O 111 A mixture of any one of the following, wherein the mass ratio of bromobenzene to the oily hydrophobic solvent is 0.5-0.7.

[0013] B. Preparation of aqueous phase-sol

[0014] Aluminum powder with a particle size of 100-200 μm is slowly added to a 10-20 wt% hydrochloric acid solution while stirring to prepare an aluminum sol. The aluminum content is 10-15 wt%, the Al / Cl mass ratio is 0.5-2.5, and the pH is 2-4. An organic amine is added at 0-10℃ and mixed thoroughly to obtain an aqueous sol. NH4+ is present in the sol. + Al 3+ The molar ratio is 0.2-0.5; the organic amine is hexamethylenetetramine (C6H4H4O2). 12 N4) or urea (CO(NH)).

[0015] Preparation of C.MS@Al2O3

[0016] Using a coaxial double-droplet forming device (see patent number: CN114849701B): The inner oil phase and the aqueous-sol phase are respectively loaded into tank 1 and tank 2. The inner oil phase in tank 1 is pumped into the inner tube of the coaxial double dropper at a flow rate of 6-10 mL / h by a transfer pump; simultaneously, the aqueous-sol phase in tank 2 is pumped into the outer tube of the coaxial double dropper at a flow rate of 80-120 mL / h by a transfer pump; water-in-oil sol spheres are formed at the dropper outlet, and the sol spheres are dripped dropwise into a reactor containing forming oil at 80-100℃. After high-temperature solidification, the sol spheres are filtered out. The microspheres are then transferred to an aging vessel and aged at 140-160℃ for 6-10 hours. After aging, the microspheres are washed with hot water at 50-70℃ until there are no chloride ions or oil stains in the washing water. They are then dried in an oven at 100-120℃ for 12-24 hours. Finally, they are heated to 900-1000℃ in a muffle furnace at a heating rate of 5-10℃ / min and held at that temperature for 4-8 hours to obtain hollow spherical alumina carriers MS@Al2O3 with a diameter of 2.5-4.0mm, a shell thickness of 0.5-1.5mm, and containing molecular sieve material inside.

[0017] The molding oil is one of vacuum pump oil, dimethyl silicone oil, or paraffin oil.

[0018] D. Preparation of catalyst MOx / MS@Al2O3

[0019] Soluble M salt was weighed and dissolved in deionized water. After thorough ultrasonic dissolution, an impregnation solution with an M content of 0.50-2.50 mol / L was prepared. The impregnation solution was measured according to the saturated water absorption rate of the MS@Al2O3 support, and the impregnation solution was uniformly sprayed onto the MS@Al2O3 support using a vacuum-spray method. The support was then removed and dried at 60-100℃ for 16-24 hours. The support was then heated to 500-800℃ in a muffle furnace at a heating rate of 2-10℃ / min for 4-6 hours to obtain the catalyst MOx / MS@Al2O3. The catalyst has metal oxide MOx loaded on its outer surface and pores, and the support is a hollow spherical alumina containing molecular sieve material.

[0020] The soluble M salt is one of the nitrates, chlorides, sulfates, and hydroxides of silicon, indium, gallium, and zinc. Preferably, it is ZnSO4, GaCl3, Na2SiO3, or In(NO3)3·3H2O.

[0021] The obtained catalyst was characterized as follows:

[0022] Figure 1 The figures show a model diagram (a), a cross-sectional view (b), an enlarged view of the cavity filling material (c), a scanning electron microscope image (d), gallium element distribution (e), and silicon element distribution (f) of the Ga2O3 / HZSM-5@Al2O3 catalytic material prepared in Example 2. It can be seen from the figures that gallium oxide is well dispersed on the surface of the support and in the pores, while the molecular sieve material is filled in the hollow cavity. The molecular sieve size is 2-40 μm, the diameter of the hollow cavity is 1.16 mm, and the overall size is 3.16 mm.

[0023] Figure 2 The image shows the X-ray diffraction (XRD) pattern of the Ga2O3 / HZSM-5@Al2O3 catalytic material prepared in Example 2. The peak positions in the image correspond to the characteristic diffraction peaks of Ga2O3 and γ-alumina, respectively, and can correspond to the characteristic diffraction peaks of pure HZSM-5 molecular sieve, indicating the successful loading of HZSM-5 molecular sieve material and the successful loading of metal oxide Ga2O3.

[0024] Figure 3 Figures 1-2 show the low-temperature nitrogen adsorption-desorption curves and pore size distribution of the ZnO / ZSM-5@Al2O3 catalyst prepared in Example 3. Figure a shows the low-temperature nitrogen adsorption-desorption curve, which is type IV, indicating that the support has a good mesoporous structure. Figure b shows the pore size distribution, which shows small pores smaller than 10 nm and large pores around 20 nm, indicating that the internal molecular sieve material is a microporous material with a pore size of less than 5 nm, and the support pore size is between 15-20 nm.

[0025] Figure 4The figures show a model diagram (a), a cross-sectional view (b), an enlarged view of the cavity filling material (c), a scanning electron microscope image (d), an indium elemental distribution (e), and a silicon elemental distribution (f) of the In2O3 / SBA-15@Al2O3 catalytic material prepared in Example 1. As can be seen from the figures, indium oxide is well dispersed on the surface of the support and in the pores, while the molecular sieve material is filled in the hollow cavity. The molecular sieve size is 2-20 μm, the diameter of the hollow cavity is 1.15 mm, and the overall size is 3.15 mm.

[0026] Figure 5 The image shows the X-ray diffraction (XRD) pattern of the In2O3 / HZSM-5@Al2O3 catalytic material prepared in Example 4. The peak positions in the image correspond to the characteristic diffraction peaks of In2O3 and γ-alumina, respectively, and also correspond to the characteristic diffraction peaks of pure HZSM-5 molecular sieve, indicating the successful loading of HZSM-5 molecular sieve material and the successful loading of the metal oxide In2O3.

[0027] Figure 6 Figures 1-4 show the low-temperature nitrogen adsorption-desorption curves and pore size distribution of the In2O3 / HZSM-5@Al2O3 catalyst prepared in Example 4. Figure a shows the low-temperature nitrogen adsorption-desorption curve, which is type IV, indicating that the support has a good mesoporous structure. Figure b shows the pore size distribution, which shows small pores smaller than 10 nm and large pores around 20 nm, indicating that the internal molecular sieve material is a microporous material with a pore size of less than 5 nm, and the support pore size is between 15-20 nm.

[0028] The beneficial effects of this invention are as follows: An inner oil phase containing molecular sieve material and an aqueous phase containing aluminum sol are molded using a coaxial double-droplet molding device to obtain an in-situ water-in-oil structured gel sphere. After aging and calcination, a hollow spherical alumina support MS@Al2O3 containing molecular sieve material is obtained. A one-step vacuum-spray method is used to load soluble salts of metal oxides onto the surface and pores of the support, followed by gas-phase oxidation to oxidize the surface-loaded soluble metal salts into metal oxides. The catalytic material obtained by this method has physical segmentation sites, with different active components loaded inside and outside the hollow support. In application, the feed gas undergoes a first-step catalytic reaction on the metal oxides on the outer surface or pores of the catalyst. The products of the first-step reaction diffuse into the catalyst cavity and undergo a second-step catalytic reaction on the molecular sieve material inside the cavity. The products of the first-step reaction serve as reactants in the second-step reaction, reducing reaction steps, energy consumption, and by-product generation, saving reactant usage, and effectively improving the efficiency of the catalytic reaction. This method can be used for industrial tandem reactions. Attached Figure Description

[0029] Figure 1The images show a model diagram (a), a cross-sectional view (a), an enlarged view of the cavity filling material (c), a scanning electron microscope image (d), gallium element distribution (e), and silicon element distribution (f) of the Ga2O3 / HZSM-5@Al2O3 catalytic material prepared in Example 2.

[0030] Figure 2 The image shows the X-ray diffraction (XRD) pattern of the Ga2O3 / HZSM-5@Al2O3 catalytic material prepared in Example 2.

[0031] Figure 3 The figures (a) and (b) are the low-temperature nitrogen adsorption-desorption curves and pore size distribution diagrams of the ZnO / ZSM-5@Al2O3 catalyst material prepared in Example 3, respectively.

[0032] Figure 4 The following images show the model diagram (a), cross-sectional view (b), magnified view (c), scanning electron microscope image (d), indium elemental distribution (e), and silicon elemental distribution of the In2O3 / SBA-15@Al2O3 catalyst material prepared in Example 1.

[0033] Figure 5 The image shows the X-ray diffraction (XRD) pattern of the In2O3 / HZSM-5@Al2O3 catalytic material prepared in Example 4.

[0034] Figure 6 The figures (a) and (b) are the low-temperature nitrogen adsorption-desorption curves (a) and pore size distribution diagrams (b) of the In2O3 / HZSM-5@Al2O3 catalyst material prepared in Example 4, respectively. Detailed Implementation

[0035] Example 1

[0036] The target catalytic material prepared was In2O3 / SBA-15@Al2O3, wherein the In2O3 loading was 7wt% and the In2O3 / SBA-15 mass ratio was 0.95. SBA-15 is a type of molecular sieve material.

[0037] A. Preparation of the internal oil phase

[0038] Weigh 1.6g of SBA-15 molecular sieve material with a particle size of 2-20μm and disperse it evenly in 10mL of a bromobenzene-liquid paraffin mixed solution with a bromobenzene mass ratio of 0.5 to obtain the inner oil phase.

[0039] B. Preparation of aqueous phase-sol

[0040] Weigh 6g of aluminum powder with a particle size of 100-200μm and slowly add it to 40mL of 10wt% hydrochloric acid solution while stirring to prepare an 11.5wt% aluminum sol with an Al / Cl mass ratio of 1.30 and a pH of approximately 4. In an ice-water bath, add 3.12g of hexamethylenetetramine to the above aluminum sol and mix thoroughly to obtain an aqueous sol.

[0041] Preparation of C.SBA-15@Al2O3

[0042] Hollow spherical alumina carriers SBA-15@Al2O3 containing molecular sieve material were prepared using a coaxial double-dropper forming device. The steps were as follows: the inner oil phase and the aqueous-sol phase were loaded into tank 1 and tank 2, respectively. The inner oil phase in tank 1 was pumped into the inner tube of the coaxial double-dropper device at a flow rate of 8 mL / h using a transfer pump; simultaneously, the aqueous-sol phase in tank 2 was pumped into the outer tube of the coaxial double-dropper device at a flow rate of 80 mL / h using a transfer pump; water-in-oil sol spheres were formed at the dropper outlet, and the sol spheres were dripped into a hot oil column containing 90°C vacuum pump oil. After solidification, the sol-gel microspheres are filtered out and then transferred to an aging reactor for aging at 160℃ for 10 hours. The aged microspheres are washed with 60℃ hot water until there are no chloride ions or oil stains in the washing water, and then dried in an oven at 100℃ for 12 hours. Then, the temperature is raised to 960℃ in a muffle furnace at a heating rate of 5℃ / min and held for 4 hours to obtain a θ-type hollow spherical alumina carrier SBA-15@Al2O3 with a diameter of 3.15mm, a shell thickness of 1.0mm, and containing SBA-15 molecular sieve material inside.

[0043] D. Loading In2O3 onto the outer surface of SBA-15@Al2O3

[0044] 0.1789 g of In(NO3)3·3H2O solid was weighed and dissolved in 1 mL of deionized water. After thorough ultrasonic dissolution, an impregnation solution was prepared, with an In(NO3)3·3H2O content of 0.56 mol / L. Using a vacuum-spray method, 1 g of the hollow spherical SBA-15@Al2O3 support prepared in step C was placed in a vacuum flask, and a vacuum pump was used to create a vacuum. The impregnation solution was then placed in a separatory funnel and slowly added dropwise while stirring until completely drained. The solution was dried at 90 °C for 24 hours; then oxidized in a muffle furnace at a heating rate of 10 °C / min to 800 °C for 4 hours to obtain an In2O3 / SBA-15@Al2O3 catalytic material with SBA-15 molecular sieve internally loaded and In2O3 loaded on the outer surface. The mass percentage of In2O3 to the support SBA-15@Al2O3 was 7 wt%, and the In2O3 / SBA-15 mass ratio was 0.95. The results of various performance tests are shown in Table 1. The catalyst size was measured using an optical microscope, and the types and contents of oxides were observed and analyzed using a scanning electron microscope (SEM) equipped with EDS (energy dispersive spectroscopy). The catalyst bulk density was calculated using a precision balance.

[0045] Example 2

[0046] The target catalytic material prepared was Ga2O3 / HZSM-5@Al2O3, wherein the loading of Ga2O3 was 15wt% and the mass ratio of Ga2O3 / HZSM-5 was 2.26. HZSM-5 is a type of molecular sieve material.

[0047] A. Preparation of the internal oil phase

[0048] 2.4 g of HZSM-5 molecular sieve material with a particle size of 2-40 μm was weighed and uniformly dispersed in 10 mL of a bromobenzene-bromocyclohexane mixed solution with a bromobenzene mass ratio of 0.5 to obtain the inner oil phase.

[0049] B. Preparation of aqueous phase-sol

[0050] Weigh 7.5 g of aluminum powder with a particle size of 100-200 μm and slowly add it to 40 mL of 15 wt% hydrochloric acid solution while stirring to prepare an aluminum sol with a 14.4 wt% content, wherein the Al / Cl mass ratio is 1.15 and the pH is approximately 4. In an ice-water bath, add 4.16 g of hexamethylenetetramine to the above aluminum sol and mix thoroughly to obtain an aqueous sol.

[0051] Preparation of C.HZSM-5@Al2O3

[0052] Hollow spherical alumina carriers HZSM-5@Al2O3 containing molecular sieve material were prepared using a coaxial double-dropper forming device. The steps were as follows: the inner oil phase and the aqueous-sol phase were loaded into tank 1 and tank 2, respectively. The inner oil phase in tank 1 was pumped into the inner tube of the coaxial double-dropper device at a flow rate of 6 mL / h. At the same time, the aqueous-sol phase in tank 2 was pumped into the outer tube of the coaxial double-dropper device at a flow rate of 100 mL / h. Water-in-oil sol spheres were formed at the dropper outlet, and the sol spheres were dripped into hot oil containing 90°C dimethyl silicone oil. In the column, after solidification, the sol-gel microspheres are filtered out and then transferred to an aging reactor for aging at 160℃ for 6 hours. The aged microspheres are washed with 60℃ hot water until there are no chloride ions and oil stains in the washing water, and then dried in an oven at 100℃ for 16 hours. Then, the temperature is raised to 960℃ in a muffle furnace at a heating rate of 10℃ / min and held for 4 hours to obtain a θ-type hollow spherical alumina carrier HZSM-5@Al2O3 with a diameter of 3.16mm, a shell thickness of 1.0mm, and containing HZSM-5 molecular sieve material inside.

[0053] D. Loading Ga2O3 onto the outer surface of HZSM-5@Al2O3

[0054] 0.1316 g of solid GaCl3 was weighed and dissolved in 1 mL of deionized water. After thorough ultrasonic dissolution, an impregnation solution was prepared, with a GaCl3 content of 0.75 mol / L. Using a vacuum-spray method, 1 g of the hollow spherical HZSM-5@Al2O3 support prepared in step C was placed in a vacuum filtration flask, and a vacuum pump was used to create a vacuum. The impregnation solution was then placed in a separatory funnel and slowly added dropwise while stirring until completely drained. The solution was dried at 100 °C for 20 hours; then oxidized in a muffle furnace at a heating rate of 5 °C / min to 650 °C for 4 hours to obtain a Ga2O3 / HZSM-5@Al2O3 catalytic material with an internally loaded HZSM-5 molecular sieve and an externally loaded Ga2O3 surface. The mass percentage of Ga2O3 to the support HZSM-5@Al2O3 was 15 wt%, and the mass ratio of Ga2O3 to HZSM-5 was 2.26. The catalyst's various performance tests were conducted using the same method as in Implementation 1, and the results are shown in Table 1.

[0055] Example 3

[0056] The target catalytic material prepared was ZnO / ZSM-5@Al2O3, wherein the ZnO loading was 15wt% and the ZnO / ZSM-5 mass ratio was 3.05. ZSM-5 is a type of molecular sieve material.

[0057] A. Preparation of the internal oil phase

[0058] Weigh 1.6g of ZSM-5 molecular sieve material with a particle size of 80-100μm and disperse it uniformly in 10mL of a bromobenzene-poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) mixed solution with a bromobenzene mass ratio of 0.6 to obtain the inner oil phase.

[0059] B. Preparation of Sol-Aqueous Phase

[0060] Weigh 6g of aluminum powder with a particle size of 100-200μm and slowly add it to 40mL of 20wt% hydrochloric acid solution while stirring to prepare an 11.5wt% aluminum sol with an Al / Cl mass ratio of 0.65 and a pH of approximately 4. In an ice-water bath, add 4.16g of hexamethylenetetramine to the above aluminum sol and mix thoroughly to obtain an aqueous sol.

[0061] Preparation of C.ZSM-5@Al2O3

[0062] Hollow spherical alumina carriers ZSM-5@Al2O3 containing molecular sieve material were prepared using a coaxial double-dropper forming device. The steps were as follows: the inner oil phase and the aqueous-sol phase were loaded into tank 1 and tank 2, respectively. The inner oil phase in tank 1 was pumped into the inner tube of the coaxial double-dropper device at a flow rate of 8 mL / h; simultaneously, the aqueous-sol phase in tank 2 was pumped into the outer tube of the coaxial double-dropper device at a flow rate of 120 mL / h; an oil-in-water sol ball was formed at the dropper outlet, and the sol ball was dripped into a hot water bath containing 90°C dimethyl silicone oil. After solidification in the oil column, the sol-gel microspheres were filtered out and then transferred to an aging reactor for aging at 170°C for 6 hours. The aged microspheres were washed with 60°C hot water until no chloride ions or oil stains were present in the wash water, and then dried in an oven at 100°C for 24 hours. The temperature was then increased to 960°C in a muffle furnace at a rate of 10°C / min and held for 4 hours to obtain θ-type hollow spherical alumina carrier ZSM-5@Al2O3 with a diameter of 3.86 mm, a shell thickness of 1.5 mm, and containing ZSM-5 molecular sieve material inside.

[0063] D. Loading ZnO onto the outer surface of ZSM-5@Al2O3

[0064] 0.2975 g of ZnSO4 solid was weighed and dissolved in 1 mL of deionized water. After thorough ultrasonic dissolution, an impregnation solution was prepared, with a ZnSO4 content of 1.03 mol / L. Using a vacuum-spray method, 1 g of the hollow spherical ZSM-5@Al2O3 support prepared in step C was placed in a vacuum filtration flask, and a vacuum pump was used to create a vacuum. The impregnation solution was then placed in a separatory funnel and slowly added dropwise while stirring until completely drained. The solution was dried at 60 °C for 24 hours; then oxidized in a muffle furnace at a heating rate of 5 °C / min to 550 °C for 4 hours to obtain a ZnO / ZSM-5@Al2O3 catalytic material with ZSM-5 molecular sieve internally loaded and ZnO loaded on the outer surface. The mass percentage of ZnO to the ZSM-5@Al2O3 support was 15 wt%, and the ZnO / ZSM-5 mass ratio was 3.05. The catalyst's various performance tests were conducted using the same method as in Implementation 1, and the results are shown in Table 1.

[0065] Example 4

[0066] The target catalytic material prepared was In2O3 / HZSM-5@Al2O3, wherein the loading of In2O3 was 10wt% and the mass ratio of In2O3 / HZSM-5 was 1.36. HZSM-5 is a type of molecular sieve material.

[0067] A. Preparation of the internal oil phase

[0068] Weigh 1.6g of HZSM-5 molecular sieve material with a particle size of 2-20μm and disperse it uniformly in 10mL of a bromobenzene-poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) mixed solution with a bromobenzene mass ratio of 0.7 to obtain the inner oil phase.

[0069] B. Preparation of Sol-Aqueous Phase

[0070] Weigh 6g of aluminum powder with a particle size of 100-200μm and slowly add it to 40mL of 10wt% hydrochloric acid solution while stirring to prepare an 11.5wt% aluminum sol with an Al / Cl mass ratio of 1.30 and a pH of approximately 4. In an ice-water bath, add 4.16g of hexamethylenetetramine to the above aluminum sol and mix thoroughly to obtain an aqueous sol.

[0071] Preparation of C.HZSM-5@Al2O3

[0072] Hollow spherical alumina carriers HZSM-5@Al2O3 containing molecular sieve material were prepared using a coaxial double-dropper forming device. The steps were as follows: the inner oil phase and the aqueous-sol phase were loaded into tank 1 and tank 2, respectively. The inner oil phase in tank 1 was pumped into the inner tube of the coaxial double-dropper device at a flow rate of 10 mL / h. At the same time, the aqueous-sol phase in tank 2 was pumped into the outer tube of the coaxial double-dropper device at a flow rate of 100 mL / h. Water-in-oil sol spheres were formed at the dropper outlet, and the sol spheres were dripped into hot oil containing 90°C vacuum pump oil. In the column, after solidification, the sol-gel microspheres are filtered out and then transferred to an aging kettle for aging at 170℃ for 6 hours. The aged microspheres are washed with 60℃ hot water until there are no chloride ions and oil stains in the washing water, and then dried in an oven at 100℃ for 14 hours. Then, the temperature is raised to 960℃ in a muffle furnace at a heating rate of 10℃ / min and held for 8 hours to obtain a θ-type hollow spherical alumina carrier HZSM-5@Al2O3 with a diameter of 3.97mm, a shell thickness of 1.0mm, and containing HZSM-5 molecular sieve material inside.

[0073] D. Loading In2O3 onto the outer surface of HZSM-5@Al2O3

[0074] 0.2556 g of In(NO3)3·3H2O solid was weighed and dissolved in 1 mL of deionized water. After thorough ultrasonic dissolution, an impregnation solution was prepared, with an In(NO3)3·3H2O content of 0.80 mol / L. Using a vacuum-spray method, 1 g of the hollow spherical HZSM-5@Al2O3 support prepared in step C was placed in a vacuum flask, and a vacuum pump was used to create a vacuum. The impregnation solution was then placed in a separatory funnel and slowly added dropwise while stirring until completely drained. The solution was dried at 100 °C for 16 hours; then oxidized in a muffle furnace at a heating rate of 5 °C / min to 800 °C for 6 hours to obtain an In2O3 / HZSM-5@Al2O3 catalytic material with ZSM-5 molecular sieve internally loaded and In2O3 loaded on the outer surface. The mass percentage of In2O3 to the support HZSM-5@Al2O3 was 10wt%, and the mass ratio of In2O3 / HZSM-5 was 1.36. The catalyst's performance was tested using the same method as in Example 1, and the results are shown in Table 1.

[0075] Example 5

[0076] The target catalytic material prepared was In2O3-SiO2 / ZSM-5@Al2O3, wherein the loading of In2O3 and SiO2 was 15wt%, and the mass ratio of SiO2 / ZSM-5 to In2O3 / ZSM-5 was 2.71. ZSM-5 is a type of molecular sieve material.

[0077] A. Preparation of the internal oil phase

[0078] Weigh 1.6g of ZSM-5 molecular sieve material with a particle size of 80-100μm and disperse it uniformly in 10mL of a bromobenzene-liquid paraffin mixed solution with a bromobenzene mass ratio of 0.6 to obtain the inner oil phase.

[0079] B. Preparation of aqueous phase-sol

[0080] Weigh 7.5 g of aluminum powder with a particle size of 100-200 μm and slowly add it to 40 mL of 10 wt% hydrochloric acid solution while stirring to prepare an aluminum sol with a 14.4 wt% content, wherein the Al / Cl mass ratio is 1.62 and the pH is approximately 4. In an ice-water bath, add 3.12 g of hexamethylenetetramine to the above aluminum sol and mix thoroughly to obtain an aqueous sol.

[0081] Preparation of C.ZSM-5@Al2O3

[0082] Hollow spherical alumina carriers ZSM-5@Al2O3 containing molecular sieve material were prepared using a coaxial double-dropper forming device. The steps were as follows: the inner oil phase and the aqueous-sol phase were loaded into tank 1 and tank 2, respectively. The inner oil phase in tank 1 was pumped into the inner tube of the coaxial double-dropper device at a flow rate of 6 mL / h using a transfer pump; simultaneously, the aqueous-sol phase in tank 2 was pumped into the outer tube of the coaxial double-dropper device at a flow rate of 80 mL / h using a transfer pump; water-in-oil sol spheres were formed at the dropper outlet, and the sol spheres were dripped into hot oil containing 90°C vacuum pump oil. In the column, after solidification, the sol-gel microspheres are filtered out and then transferred to an aging reactor for aging at 170℃ for 6 hours. The aged microspheres are washed with 60℃ hot water until there are no chloride ions or oil stains in the washing water, and then dried in an oven at 110℃ for 14 hours. Then, the temperature is raised to 960℃ in a muffle furnace at a heating rate of 5℃ / min and held for 8 hours to obtain θ-type hollow spherical alumina carrier ZSM-5@Al2O3 with a diameter of 2.88mm, a shell thickness of 0.7mm, and containing ZSM-5 molecular sieve material inside.

[0083] D. Loading SiO2 onto the outer surface of ZSM-5@Al2O3 and loading In2O3 into the carrier channels.

[0084] Weigh 0.3834 g of In(NO3)3·3H2O and 0.3046 g of Na2SiO3 solid and dissolve them in 1 mL of deionized water. After thorough sonication, an impregnation solution is prepared. The impregnation solution contains 1.20 mol / L of In(NO3)3·3H2O and 2.50 mol / L of Na2SiO3. Using a vacuum-spray method, place 1 g of the hollow spherical ZSM-5@Al2O3 support prepared in step C into a vacuum filtration flask, evacuate to a vacuum level using a vacuum pump, and place the above impregnation solution in a separatory funnel and slowly add it dropwise while stirring until the impregnation solution is completely added. The catalyst was dried at 80℃ for 16 hours, then oxidized in a muffle furnace at a heating rate of 2℃ / min to 800℃ for 6 hours to obtain an In2O3-SiO2 / ZSM-5@Al2O3 catalyst with ZSM-5 molecular sieve internally loaded, SiO2 loaded on the outer surface, and In2O3 loaded in the support channels. The mass percentage of In2O3 and SiO2 to the support ZSM-5@Al2O3 was 15wt%, and the mass ratio of SiO2 / ZSM-5 to In2O3 / ZSM-5 was 2.71. The catalyst's performance was tested using the same method as in Example 1, and the results are shown in Table 1.

[0085] Table 1

[0086] Example 1 Example 2 Example 3 Example 4 Example 5 Outer diameter (mm) 3.15 3.16 3.86 3.97 2.88 Wall thickness (mm) 1.0 1.0 1.5 1.0 0.7 Oxide types <![CDATA[In2O3]]> <![CDATA[Ga2O3]]> ZnO <![CDATA[In2O3]]> <![CDATA[In2O3、SiO2]]> oxide content 7wt% 15wt% 15wt% 10wt% 15wt%, 15wt% <![CDATA[Bulk density (g / cm 3 )]]> 0.33 0.33 0.27 0.25 0.38

[0087] The feasibility of millimeter-scale catalytic materials with multiple active component loading sites in a hollow spherical structure was demonstrated through various characterization methods. The loading of metal oxides on the surface or within the pores of a support, and the loading of molecular sieve materials within the hollow cavity, were proven. The spatial separation of the active components allows for stepwise tandem reactions; the hollow cavity and mesopores facilitate the diffusion of the products of the first step reaction into the catalyst cavity, where the second step reaction occurs on the molecular sieve material inside the cavity. This makes the application of the catalyst in industrial tandem reactions possible.

Claims

1. A method for preparing a millimeter-scale catalytic material with a hollow spherical structure and multiple active component loading sites, the catalytic material being designated MOx / MS@Al2O3, wherein MS@Al2O3 is the support, consisting of spherical particles of 2.5-4.0 mm in size; MS is encapsulated within an Al2O3 shell with a shell thickness of 0.5-1.5 mm and a shell pore size of 10-50 nm; MOx is loaded onto the surface of the MS@Al2O3 support; MS represents a molecular sieve, any one of ZSM-5, HZSM-5, SAPO-34, and SBA-15; the mass ratio of MOx / MS is 0.5-3.5; the MS particle size is 2-100 μm; the silicon-to-aluminum ratio is 25-30; MOx is one or two of SiO2, In2O3, Ga2O3, and ZnO; and the bulk density of MOx / MS@Al2O3 is 0.2-0.4 g / cm³. 3 The crushing strength is 10-20 N, and the MOx content of the MS@Al2O3 support is 7-15 wt%. The catalytic material is prepared according to the following specific steps: A. Preparation of the internal oil phase Weigh out molecular sieve material with MS particle size of 2-100 μm and uniformly disperse it in an oily hydrophobic aqueous solution to prepare an internal oil phase with MS content of 0.15-0.25 g / mL; The oleophobic aqueous solution is a mixture of bromobenzene and any one of liquid paraffin, bromocyclohexane, or poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol), wherein the mass ratio of bromobenzene to the oleophobic aqueous solution is 0.5-0.

7. B. Preparation of aqueous phase-sol Aluminum powder with a particle size of 100-200 μm was slowly added to a 10-20 wt% hydrochloric acid solution while stirring to prepare an aluminum sol. The aluminum content was 10-15 wt%, the Al / Cl mass ratio was 0.5-2.5, and the pH was 2-4. An organic amine was added at 0-10 °C and mixed thoroughly to obtain an aqueous sol. + Al 3+ The molar ratio is 0.2-0.5; the organic amine is hexamethylenetetramine (C6H4H4). 12 N4; C. Preparation of MS@Al2O3 Using a coaxial double-droplet molding device: The inner oil phase and the aqueous-sol phase are respectively loaded into tank 1 and tank 2. The inner oil phase in tank 1 is pumped into the inner tube of the coaxial double droplet at a flow rate of 6-10 mL / h; simultaneously, the aqueous-sol phase in tank 2 is pumped into the outer tube of the coaxial double droplet at a flow rate of 80-120 mL / h; water-in-oil sol spheres are formed at the droplet outlet. The sol spheres are dripped into a reactor containing molding oil at 80-100 ℃. After high-temperature solidification, the sol spheres are filtered out and then transferred to an aging tank for aging at 140-160 ℃ for 6-10 hours; the aged spheres are then processed with 50-70... o Wash with hot water until the wash water is free of chloride ions and oil, then dry in an oven at 100-120 ℃ for 12-24 hours; then heat to 900-1000 ℃ in a muffle furnace at a heating rate of 5-10 ℃ / min and hold for 4-8 hours to obtain hollow spherical alumina carrier MS@Al2O3 with a diameter of 2.5-4.0 mm, a shell thickness of 0.5-1.5 mm, and containing molecular sieve material inside. The molding oil is one of vacuum pump oil, dimethyl silicone oil, and paraffin oil; D. Preparation of catalyst MOx / MS@Al2O3 Weigh out soluble M salt and dissolve it in deionized water. After thorough ultrasonic dissolution, prepare an impregnation solution with an M content of 0.50-2.50 mol / L. Measure the impregnation solution according to the saturated water absorption rate of the MS@Al2O3 support, and uniformly spray the impregnation solution onto the MS@Al2O3 support using a vacuum-spray method. Remove the support and dry it at 60-100 ℃ for 16-24 hours. Then, heat it in a muffle furnace at 2-10 ℃. o Increase the temperature at a rate of C / min to 500-800. o After oxidation with C for 4-6 hours, the catalyst MOx / MS@Al2O3 was obtained. The catalyst has metal oxide MOx loaded on its outer surface and pores, and the support is hollow spherical alumina containing molecular sieve material.

2. The method for preparing millimeter-scale catalytic material with hollow spherical structure and multiple active component loading sites according to claim 1, characterized in that the soluble M salt in step D is: ZnSO4, GaCl3, Na2SiO3 or In(NO3)3·3H2O.

Images