AEL-structured aluminophosphate molecular sieve packaged metal catalyst and preparation method thereof

Abstract

The invention provides an aluminophosphate molecular sieve encapsulated metal catalyst with an AEL structure and a preparation method of the aluminophosphate molecular sieve encapsulated metal catalyst, and belongs to the technical field of zeolite molecular sieve porous materials. According to the present invention, the AEL structure aluminophosphate molecular sieve is adopted to encapsulate the metal, the xerogel conversion method is adopted to synthesize the AEL structure aluminophosphate molecular sieve encapsulated metal catalyst in the presence of the epoxypropane, the structure guiding effect is provided through the suitable template agent, the pore structure is adjusted, and the regular pore channel is formed so as to coat the metal particles; the aluminophosphate molecular sieve encapsulated metal catalyst with the AEL structure prepared by the invention simultaneously has the pore channel advantage of zeolite and the active site of metal nanoparticles, and the molecular size can be effectively screened; according to the present invention, the metal particles and the zeolite are used as the catalyst, the mass transfer effect is adjusted on the molecular level, the opportunity is provided for the shape selective catalysis, the selectivity, the stability and the activity of the catalyst are effectively improved, and the rigid skeleton of the metal particle-zeolite catalyst provides the huge advantages for the application in the severe environment.

Description

Technical Field

[0001] The invention relates to the technical field of zeolite molecular sieve porous materials, and in particular to an aluminum phosphate molecular sieve encapsulated metal catalyst with an AEL structure and a preparation method thereof. Background Art

[0002] Zeolite molecular sieve is an inorganic material with high crystallinity composed of an ordered distribution of microporous structures with a diameter of less than 1nm. It has extremely wide applications in the petrochemical industry. The zeolite framework is usually composed of TO4 tetrahedrons (T is Si, Al and P, etc.). As of 2024, the International Zeolite Association (IZA) has collected a total of 265 types of zeolite frameworks (http: / / www.iza-structure.org / databases / ). Based on the diversity and structural versatility of zeolite molecular sieves, researchers have deeply studied the method of preparing heterogeneous catalysts by loading metal nanoparticles on zeolites, and have made great progress, such as the successful preparation of a bifunctional supported metal catalyst that is effectively used in the cascade reaction of hydrogenation / dehydrogenation and cracking / isomerization.

[0003] Compared with other carriers, zeolite molecular sieves have another important and unique property - shape selectivity. Zeolite molecular sieves have regular cavities and nanopores, which can provide space and sites for encapsulating foreign active centers. For many heterogeneous catalysts, controlling the nature, location and accessibility of catalytic sites is the key to achieving optimal performance. In the field of heterogeneous catalysis, metal@zeolite materials have both the pore advantages of zeolites and the active sites of metal nanoparticles, and show superior performance in improving selectivity in catalytic reactions and reducing coking deactivation.

[0004] However, the agglomeration and sintering effects of metal nanoparticles usually lead to the loss of catalytic performance during the reaction process. Encapsulating catalytically active metal particles inside zeolite molecular sieves with advantages such as uniform pores, structural diversity and large specific surface area is of great significance to solving the above problems. For example, the 10-membered ring structure of the currently commonly used ZSM-5 zeolite crystal (MFI topology) has a maximum pore accessibility of 0.64nm, which limits the growth of metal nanoparticles embedded therein.

[0005] Therefore, how to adjust the pore structure of molecular sieves to improve the effect of molecular sieve encapsulation of metals has become an important research topic for those skilled in the art. Summary of the invention

[0006] The purpose of the present invention is to provide an aluminum phosphate molecular sieve encapsulated metal catalyst with an AEL structure and a preparation method thereof. Metal is introduced into the gelation process of synthesizing nano molecular sieves by a dry gel conversion method with the participation of propylene oxide, and a suitable template agent is selected to adjust the pore structure so that the metal is encapsulated in the zeolite molecular sieve during its growth. The obtained aluminum phosphate molecular sieve encapsulated metal catalyst with an AEL structure has the pore advantages of zeolite and the active sites of metal nanoparticles. The rigid skeleton of the zeolite brings great advantages to its application in harsh environments, and the unique nanopores also provide opportunities for shape-selective catalysis.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0008] The present invention provides a method for preparing an aluminum phosphate molecular sieve encapsulated metal catalyst of an AEL structure, comprising the following steps:

[0009] (1) adding a metal solution Mo, (3-mercaptopropyl)trimethoxysilane, an aluminum source, phosphoric acid, a heteroatom M, hydrofluoric acid and a template agent to deionized water in sequence, stirring evenly at room temperature, stirring in an ice bath, and then adding propylene oxide;

[0010] (2) Aging to obtain a hydrogel and first drying to obtain a xerogel;

[0011] (3) heating the crystallized dry gel, ultrasonicating, washing with water to obtain a solid product, drying the solid product for a second time, grinding it, and calcining it to obtain an aluminum phosphate molecular sieve encapsulated metal catalyst powder with an AEL structure.

[0012] Preferably, the metal-containing solution Mo is one of solutions containing Au, Pt, Pd, Ni, Ce, Cu, Ag or Rh, and the concentration of the metal-containing solution is 0.001-2 g / mL; the aluminum source is one of crystalline aluminum chloride, pseudo-boehmite, and aluminum isopropoxide; and the heteroatom M is one of Co, Cu, Fe, Mg, Ni, Si or Zn.

[0013] Preferably, in step (1), the template agent is one of diethylamine, di-n-propylamine, di-n-butylamine or 1-ethyl-3-methylimidazole hydroxide; the phosphoric acid concentration is 10-99wt%, and the hydrofluoric acid concentration is 5-70wt%; the room temperature stirring time is 0.5-5h; the ice bath stirring temperature is -5-5°C, and the ice bath stirring time is 0.1-1.5h.

[0014] Preferably, in the hydrogel of step (2), the molar ratio of M:Al2O3:P2O5:HF:(3-mercaptopropyl)trimethoxysilane:template:propylene oxide:H2O:Mo is 0.008-1.0:0.10-5.0:0.10-8.0:0.005-0.5:0.01-1.0:0.025-3.0:1.0-100:5.0-500:1.0×10 -8 ~1.0×10 -3 .

[0015] Preferably, in step (2), the aging temperature is 50-90°C, and the aging time is 0.5-8h; the first drying temperature is 60-120°C, and the first drying time is 2-24h; the molar ratio of M:Al2O3:P2O5:HF:(3-mercaptopropyl)trimethoxysilane:template:propylene oxide:H2O:Mo in the xerogel is 0.008-1.0:0.10-5.0:0.10-8.0:0.005-0.5:0.01-1.0:0.025-3.0:1.0-100:5.0-50:1.0×10 -8 ~1.0×10 -3 .

[0016] Preferably, in step (3), the crystallization temperature is 80 to 240° C. and the crystallization time is 4 to 36 hours.

[0017] Preferably, in step (3), the temperature of the second drying is 50-120° C., and the second drying time is 2-24 hours; the power of the ultrasound is 50-350 W, and the time of the ultrasound is 5-30 minutes.

[0018] Preferably, in step (3), the calcination temperature is 400-600° C. and the calcination time is 2-12 hours.

[0019] The present invention also provides a method for preparing an aluminum phosphate molecular sieve encapsulated metal catalyst with an AEL structure and a method for preparing the aluminum phosphate molecular sieve encapsulated metal catalyst with an AEL structure.

[0020] Compared with the prior art, the present invention has the following advantages and technical effects:

[0021] (1) The present invention uses nano-aluminum phosphate molecular sieves with an AEL structure to encapsulate metals, and uses a dry gel conversion method to synthesize an aluminum phosphate molecular sieve encapsulated metal catalyst with an AEL structure in the presence of propylene oxide, and uses a suitable template agent to play a structural guiding role, while adjusting the pore structure to form regular channels so that metal particles are coated. The preparation method of the present invention has the advantages of simple operation steps, low cost, environmental friendliness, and easy industrial application.

[0022] (2) The aluminum phosphate molecular sieve encapsulated metal catalyst with AEL structure prepared by the present invention has both the pore advantages of zeolite and the active sites of metal nanoparticles. The open nanoporous channels can promote the diffusion of reactant molecules to the vicinity of the metal species fixed inside the pores, can effectively screen the molecular size, regulate the mass transfer at the molecular level, and also provide opportunities for shape-selective catalysis.

[0023] (3) The aluminum phosphate molecular sieve encapsulated metal catalyst with an AEL structure prepared by the present invention embodies the multifunctional catalytic properties of the metal@zeolite catalyst through the synergistic effect between the special framework structure of the molecular sieve and the fixed metal species, thereby effectively improving the selectivity and activity of the catalyst. The rigid framework of the metal@zeolite also brings great advantages to its application in harsh environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0025] Figure 1 The XRD spectrum of the AEL structured magnesium aluminum phosphate molecular sieve encapsulated Pt metal catalyst Pt@MgAlPO-11 synthesized in Example 1;

[0026] Figure 2 This is the nitrogen physical adsorption-desorption isotherm of the AEL-structured magnesium aluminum phosphate molecular sieve encapsulated Pt metal catalyst Pt@MgAlPO-11 synthesized in Example 1.

[0027] Figure 3 STEM photo of the AEL structured magnesium aluminum phosphate molecular sieve encapsulated Pt metal catalyst Pt@MgAlPO-11 synthesized in Example 1 DETAILED DESCRIPTION

[0028] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0029] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0030] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0031] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to the skilled artisan. The present invention description and examples are exemplary only.

[0032] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0033] The present invention provides a method for preparing an aluminum phosphate molecular sieve encapsulated metal catalyst of an AEL structure, comprising the following steps:

[0034] (1) Adding a metal-containing solution, (3-mercaptopropyl)trimethoxysilane, an aluminum source, phosphoric acid, a heteroatom, hydrofluoric acid and a template agent to deionized water in sequence, stirring at room temperature at 50-600 r / min for 0.5-5 h, stirring at 50-500 r / min for 0.1-1.5 h in an ice bath at -5-5°C, and then adding propylene oxide (PO); the metal-containing solution (Mo) is one of Au, Pt, Pd, Ni, Ce, Cu, Ag or Rh solutions, and the concentration of the metal-containing solution is 0.001-2 g / mL; the aluminum source is one of crystalline aluminum chloride, pseudo-boehmite and aluminum isopropoxide; the heteroatom M is one of Co, Cu, Fe, Mg, Ni, Si or Zn.

[0035] Preferably, the method for preparing the aluminum phosphate molecular sieve encapsulated metal catalyst with an AEL structure according to claim 1 is characterized in that, in step (1), the template agent is one of diethylamine (DEA), di-n-propylamine (DPA), di-n-butylamine (DBA) or 1-ethyl-3-methylimidazole hydroxide ([Emim]OH);

[0036] (2) aging at 50-90° C. for 0.5-8 h to obtain a hydrogel, and first drying at 60-120° C. for 2-24 h to obtain a xerogel; wherein the molar ratio of M:Al2O3:P2O5:HF:(3-mercaptopropyl)trimethoxysilane:template:PO:H2O:Mo in the xerogel is 0.008-1.0:0.10-5.0:0.10-8.0:0.005-0.5:0.01-1.0:0.025-3.0:1.0-100:5.0-50:1.0×10 -8 ~1.0×10 -3 ;

[0037] (3) The dry gel is heated at 80-240° C. for crystallization for 4-36 h, ultrasonicated at 50-350 W for 5-30 min, and washed with water three times to obtain a solid product. The solid product is dried for a second time at 50-120° C. for 2-24 h and then ground. After grinding, it is calcined at 400-600° C. for 2-12 h to obtain a molecular sieve encapsulated metal catalyst powder.

[0038] Example 1

[0039] Embodiment 1 of the present invention provides a method for preparing a Pt@MgAlPO-11 catalyst with an AEL structure, comprising the following steps:

[0040] (1) 0.2 mL of chloroplatinic acid (concentration of 0.001 g / mL), 3.27 g of (3-mercaptopropyl)trimethoxysilane, 4.02 g of crystalline aluminum chloride, 2.4 mL of 85 wt% phosphoric acid, 0.054 g of magnesium chloride hexahydrate (MgCl2·6H2O), 0.5 mL of 40 wt% hydrofluoric acid and 1.08 g of di-n-butylamine (DBA) were sequentially added to 18 mL of deionized water, and the mixture was stirred at 400 r / min at room temperature for 0.5 h, and then stirred at 100 r / min for 0.2 h in an ice bath at 3°C, and then 15 mL of propylene oxide (PO) was added;

[0041] (2) A hydrogel was obtained by aging at 50°C for 2 h, and a xerogel was obtained by first drying at 80°C for 1.5 h. The molar ratio of MgO:Al2O3:P2O5:HF:(3-mercaptopropyl)trimethoxysilane:DBA:PO:H2O:Pt in the xerogel was 0.008:1.0:1.2:0.3:0.5:0.25:8.0:20.0:4.9×10 -7 ;

[0042] (3) The xerogel was loaded into a stainless-steel autoclave with a polytetrafluoroethylene liner and heated at 110 °C for crystallization for 4 h, sonicated in an ultrasonic cleaner with a power of 150 W for 10 min, washed with water three times, dried for the second time at 90 °C for 12 h, and then ground. After grinding, it was calcined at 400 °C for 10 h in an air atmosphere to obtain the Pt@MgAlPO-11 catalyst with an AEL structure.

[0043] The Pt@MgAlPO-11 with an AEL structure prepared in Example 1 was characterized, and the results are as Figures 1 to 3 shown.

[0044] As Figure 1 shown, it is the XRD pattern of the Pt@MgAlPO-11 catalyst synthesized in Example 1. The X-ray powder diffraction (XRD) technique was used to investigate the phase of the AEL-structured Pt@MgAlPO-11 prepared in Example 1. The strong characteristic diffraction peaks at the diffraction angles 2θ = 8.09°, 9.43°, 13.20°, 15.70°, 20.49°, 21.12°, and 23.22° correspond to its (110), (020), (200), (130), (310), (002), and (240) crystal planes respectively; compared with the PDF standard card, it can be seen that the coincidence degree is relatively high, indicating that the prepared molecular sieve-encapsulated metal catalyst is an AEL topological structure with high purity; at the same time, the diffraction peaks are sharp, indicating high crystallinity.

[0045] As Figure 2 shown, it is the nitrogen physical adsorption and desorption isotherm of the Pt@MgAlPO-11 synthesized in Example 1. Nitrogen physical adsorption / desorption was used to measure the specific surface area and pore structure properties of the aluminophosphate molecular sieve-encapsulated metal catalyst with an AEL structure synthesized in Example 1 of the present invention. According to the classification of IUPAC, the above materials belong to the typical characteristics of type I + IV adsorption isotherms. At 0.0 < P / P0 < 0.1, the adsorption amount increases with the slight change of the relative pressure, which is presumably related to micropore filling; at 0.1 < P / P0 < 0.9, it can be seen that the adsorption amount changes slowly with the relative pressure, indicating a microporous structure with monolayer or quasi-monolayer adsorption; at 0.9 < P / P0 < 1.0, due to capillary condensation, an H4-type hysteresis loop appears, indicating that the material has mesoporous characteristics. Thus, it is shown that the aluminophosphate molecular sieve-encapsulated metal catalyst with an AEL structure synthesized in Example 1 has both micropores and mesopores, and the specific surface area analyzed by the BET method is 184 m 2 / g.

[0046] As Figure 3The figure shows a STEM image of Pt@MgAlPO-11 synthesized in Example 1. It can be clearly seen that Pt particles with a particle size of about 1-3 nm are encapsulated inside the molecular sieve, which proves the effectiveness of the synthesis strategy.

[0047] Example 2

[0048] Embodiment 2 of the present invention provides a method for preparing a Pt@MgAlPO-11 catalyst with an AEL structure, comprising the following steps:

[0049] (1) 0.2 mL of chloroplatinic acid (concentration: 0.001 g / mL), 3.27 g of (3-mercaptopropyl)trimethoxysilane, 4.02 g of crystalline aluminum chloride, 2.4 mL of 85 wt % phosphoric acid, 0.07 g of magnesium acetate (C4H6MgO4·4H2O), 0.5 mL of 40 wt % hydrofluoric acid and 1.08 g of di-n-butylamine (DBA) were sequentially added to 20 mL of deionized water, and the mixture was stirred at 400 r / min at room temperature for 1 h, and then stirred at 200 r / min for 0.2 h in an ice bath at 3°C, and then 17 mL of propylene oxide was added;

[0050] (2) A hydrogel was obtained by aging at 50°C for 2 h, and a xerogel was obtained by first drying at 90°C for 1.5 h. The molar ratio of MgO:Al2O3:P2O5:HF:(3-mercaptopropyl)trimethoxysilane:DBA:PO:H2O:Pt in the xerogel was 0.01:1.0:1.2:0.3:0.5:0.25:9.0:15.0:4.9×10 -7 ;

[0051] (3) The dry gel was placed in a stainless steel reactor lined with polytetrafluoroethylene and heated at 160°C for crystallization for 10 h. It was ultrasonically cleaned in a 250 W ultrasonic cleaner for 15 min, washed with water three times, dried for a second time at 100°C for 12 h, and then ground. After grinding, it was calcined at 500°C for 6 h in air atmosphere to obtain the Pt@MgAlPO-11 catalyst with AEL structure.

[0052] Example 3

[0053] Example 3 of the present invention provides a method for preparing a Pt@SAPO-11 catalyst with an AEL structure, comprising the following steps:

[0054] (1) 0.5 mL of chloroplatinic acid (concentration: 0.006 g / mL), 3 g of (3-mercaptopropyl)trimethoxysilane, 3.63 g of crystalline aluminum chloride, 2.08 mL of 85 wt % phosphoric acid, 0.27 g of white carbon black, 0.45 mL of 40 wt % hydrofluoric acid and 0.91 g of di-n-propylamine (DPA) were sequentially added to 16 mL of deionized water, stirred at 500 r / min at room temperature for 1 h, stirred at 100 r / min for 0.5 h in an ice bath at 3°C, and then 21 mL of propylene oxide was added;

[0055] (2) A hydrogel was obtained by aging at 50°C for 2 h, and a xerogel was obtained by first drying at 110°C for 1.5 h. The molar ratio of SiO2:Al2O3:P2O5:HF:(3-mercaptopropyl)trimethoxysilane:DPA:PO:H2O:Pt in the xerogel was 0.15:1.0:1.2:0.3:0.5:0.3:12.0:18.0:7.3×10 -6 ;

[0056] (3) The dry gel was placed in a stainless steel reactor lined with polytetrafluoroethylene and heated at 180°C for crystallization for 12 h. It was then ultrasonicated in a 200 W ultrasonic cleaner for 20 min, washed with water three times, dried for a second time at 110°C for 2 h, and ground. After grinding, it was calcined at 550°C for 10 h in air atmosphere to obtain the AEL structured Pt@SAPO-11 catalyst.

[0057] Example 4

[0058] Example 4 of the present invention provides a method for preparing a Pt@SAPO-11 catalyst with an AEL structure, comprising the following steps:

[0059] (1) 0.5 mL of tetraammine platinum nitrate aqueous solution (concentration: 0.05 g / mL), 0.5 g of (3-mercaptopropyl) trimethoxysilane, 6.12 g of aluminum isopropoxide, 2.08 mL of 85 wt % phosphoric acid, 1.24 g of tetraethyl orthosilicate (TEOS), 0.025 mL of 40 wt % hydrofluoric acid, and 1.5 g of 1-ethyl-3-methylimidazole hydroxide ([Emim]OH) were sequentially added to 25 mL of deionized water, and the mixture was stirred at 500 r / min at room temperature for 3 h, and then stirred at 150 r / min for 0.5 h in an ice bath at 3°C, and then 23 mL of propylene oxide was added;

[0060] (2) A hydrogel was obtained by aging at 80°C for 4 h, and a xerogel was obtained by first drying at 100°C for 2 h. The molar ratio of SiO2:Al2O3:P2O5:HF:(3-mercaptopropyl)trimethoxysilane:[Emim]OH:PO:H2O:Pt in the xerogel was 0.12:1.2:1.2:0.01:0.05:0.03:8.0:18.0:6.5×10 -5 ;

[0061] (3) The dry gel was placed in a stainless steel reactor lined with polytetrafluoroethylene and heated at 200°C for crystallization for 10 h. It was then ultrasonicated in a 300 W ultrasonic cleaner for 20 min, washed with water three times, dried for a second time at 100°C for 12 h, and then ground. After grinding, it was calcined at 500°C for 10 h in air atmosphere to obtain the AEL structured Pt@SAPO-11 catalyst.

[0062] Example 5

[0063] Embodiment 5 of the present invention provides a method for preparing a Cu@MgAlPO-11 catalyst with an AEL structure, comprising the following steps:

[0064] (1) 0.5 mL of copper nitrate aqueous solution (concentration: 0.05 g / mL), 0.08 g of (3-mercaptopropyl)trimethoxysilane, 2.04 g of aluminum isopropoxide, 1.15 mL of 85 wt % phosphoric acid, 0.03 g of magnesium acetate (C4H6MgO4·4H2O), 0.25 mL of 40 wt % hydrofluoric acid and 0.73 g of diethylamine (DEA) were sequentially added to 15 mL of deionized water, and the mixture was stirred at 600 r / min at room temperature for 2 h, and then stirred at 150 r / min for 0.1 h in an ice bath at 5°C, and then 12 mL of propylene oxide was added;

[0065] (2) A hydrogel was obtained by aging at 90°C for 5 h, and a xerogel was obtained by first drying at 120°C for 12 h. The molar ratio of MgO:Al2O3:P2O5:HF:(3-mercaptopropyl)trimethoxysilane:DEA:PO:H2O:Cu in the xerogel was 0.008:1.0:1.0:0.25:0.02:0.5:10.0:20.0:4.0×10 -4 ;

[0066] (3) The dry gel was placed in a stainless steel reactor lined with polytetrafluoroethylene and heated at 180°C for crystallization for 16 h. It was ultrasonically cleaned in a 350 W ultrasonic cleaner for 30 min, washed with water three times, dried for a second time at 120°C for 4 h, and then ground. After grinding, it was calcined at 600°C for 6 h in air atmosphere to obtain Cu@MgAlPO-11 with AEL structure.

[0067] Example 6

[0068] Embodiment 6 of the present invention provides a method for preparing a Ni@MgAlPO-11 catalyst with an AEL structure, comprising the following steps:

[0069] (1) 0.6 mL of nickel nitrate aqueous solution (concentration: 0.01 g / mL), 0.045 g of (3-mercaptopropyl)trimethoxysilane, 4.64 g of aluminum isopropoxide, 1.45 mL of 85 wt % phosphoric acid, 0.98 g of magnesium acetate (C4H6MgO4·4H2O), 0.006 mL of 40 wt % hydrofluoric acid and 4.6 g of di-n-propylamine (DPA) were sequentially added to 20 mL of deionized water, and the mixture was stirred at 500 r / min at room temperature for 2 h, and then stirred at 200 r / min for 0.1 to 1.5 h in an ice bath at 5°C, and then 26 mL of propylene oxide was added;

[0070] (2) A hydrogel was obtained by aging at 80°C for 6 h, and a xerogel was obtained by first drying at 90°C for 12 h. The molar ratio of MgO:Al2O3:P2O5:HF:(3-mercaptopropyl)trimethoxysilane:DPA:PO:H2O:Ni in the xerogel was 0.2:2.0:1.1:0.005:0.01:2.0:20.0:25.0:3.3×10 -5 ;

[0071] (3) The dry gel was placed in a stainless steel reactor lined with polytetrafluoroethylene and heated at 200°C for crystallization for 24 h. It was ultrasonically cleaned in a 250 W ultrasonic cleaner for 15 min, washed with water three times, dried for a second time at 120°C for 6 h, and then ground. After grinding, it was calcined at 400°C for 10 h in air atmosphere to obtain Ni@MgAlPO-11 with AEL structure.

[0072] Example 7

[0073] Embodiment 7 of the present invention provides a method for preparing a Ce@MgAlPO-11 catalyst with an AEL structure, comprising the following steps:

[0074] (1) 0.3 mL of cerium nitrate aqueous solution (concentration: 0.05 g / mL), 0.49 g of (3-mercaptopropyl)trimethoxysilane, 5.1 g of aluminum isopropoxide, 2.88 mL of 85 wt % phosphoric acid, 1.07 g of magnesium acetate (C4H6MgO4·4H2O), 0.006 mL of 40 wt % hydrofluoric acid and 6.46 g of di-n-butylamine (DBA) were added to 25 mL of deionized water in sequence, and the mixture was stirred at 500 r / min at room temperature for 2 h, and then stirred at 200 r / min for 0.5 h in an ice bath at 5°C, and then 29 mL of propylene oxide was added;

[0075] (2) A hydrogel was obtained by aging at 80°C for 6 h, and a xerogel was obtained by first drying at 90°C for 12 h. The molar ratio of MgO:Al2O3:P2O5:HF:(3-mercaptopropyl)trimethoxysilane:DBA:PO:H2O:Ce in the xerogel was 0.2:2.0:2.0:0.005:0.1:2.0:20.0:25.0:3.5×10 -5 ;

[0076] (3) The dry gel was placed in a stainless steel reactor lined with polytetrafluoroethylene and heated at 180°C for crystallization for 24 h. It was ultrasonically cleaned in a 250 W ultrasonic cleaner for 20 min, washed with water three times, dried for a second time at 100°C for 6 h, and then ground. After grinding, it was calcined at 500°C for 10 h in air atmosphere to obtain Ce@MgAlPO-11 with AEL structure.

[0077] Example 8

[0078] Embodiment 8 of the present invention provides a method for preparing a Pt@MgAlPO-11 catalyst with an AEL structure, comprising the following steps:

[0079] (1) 0.2 mL of chloroplatinic acid (concentration: 0.02 g / mL), 3.1 g of (3-mercaptopropyl)trimethoxysilane, 3.06 g of aluminum isopropoxide, 1.46 mL of 85 wt % phosphoric acid, 0.096 g of magnesium sulfate heptahydrate (MgSO4·7H2O), 0.07 mL of 40 wt % hydrofluoric acid, and 0.505 g of di-n-propylamine (DPA) were sequentially added to 9 mL of deionized water, and the mixture was stirred at 200 r / min at room temperature for 1 h. After stirring at 200 r / min for 0.1 h in an ice bath at 5°C, 2.9 mL of propylene oxide was added;

[0080] (2) A hydrogel was obtained by aging at 80°C for 2 h, and a xerogel was obtained by first drying at 100°C for 6 h. The molar ratio of MgO:Al2O3:P2O5:HF:(3-mercaptopropyl)trimethoxysilane:DPA:PO:H2O:Pt in the xerogel was 0.03:1.18:1.0:0.055:0.625:0.2:1.98:25.0:9.8×10 -6 ;

[0081] (3) The dry gel was placed in a stainless steel reactor lined with polytetrafluoroethylene and heated at 240°C for crystallization for 10 h. It was ultrasonically cleaned in a 150 W ultrasonic cleaner for 20 min, washed with water three times, dried for a second time at 100°C for 12 h, and then ground. After grinding, it was calcined at 600°C for 2 h in air atmosphere to obtain the Pt@MgAlPO-11 catalyst with AEL structure.

[0082] Example 9

[0083] Embodiment 9 of the present invention provides a method for preparing a Pt@MgAlPO-11 catalyst with an AEL structure, comprising the following steps:

[0084] (1) 0.4 mL of chloroplatinic acid (concentration: 0.025 g / mL), 1.24 g of (3-mercaptopropyl)trimethoxysilane, 4.08 g of aluminum isopropoxide, 1.2 mL of 85 wt % phosphoric acid, 0.12 g of magnesium sulfate heptahydrate (MgSO4·7H2O), 0.036 mL of 40 wt % hydrofluoric acid, and 0.584 g of diethylamine (DEA) were sequentially added to 16 mL of deionized water, and the mixture was stirred at 200 r / min at room temperature for 1 h. After stirring at 200 r / min for 0.1 h in an ice bath at 5°C, 5.8 mL of propylene oxide was added;

[0085] (2) A hydrogel was obtained by aging at 60°C for 2 h, and a xerogel was obtained by first drying at 80°C for 8 h. The molar ratio of MgO:Al2O3:P2O5:HF:(3-mercaptopropyl)trimethoxysilane:DEA:PO:H2O:Pt in the xerogel was 0.05:2.0:1.0:0.036:0.32:0.2:5.0:50.0:2.4×10 -5 ;

[0086] (3) The dry gel was placed in a stainless steel reactor lined with polytetrafluoroethylene and heated at 200°C for crystallization for 16 h. It was then ultrasonicated in a 150 W ultrasonic cleaner for 20 min, washed with water three times, dried for a second time at 100°C for 6 h, and then ground. After grinding, it was calcined at 500°C for 7 h in air atmosphere to obtain the Pt@MgAlPO-11 catalyst with AEL structure.

[0087] Example 10

[0088] Embodiment 10 of the present invention provides a method for preparing a Pt@MgAlPO-11 catalyst with an AEL structure, comprising the following steps:

[0089] (1) 0.2 mL of chloroplatinic acid (concentration: 0.03 g / mL), 0.124 g of (3-mercaptopropyl)trimethoxysilane, 2.41 g of crystalline aluminum chloride, 0.95 mL of 85 wt % phosphoric acid, 0.0192 g of magnesium sulfate heptahydrate (MgSO4·7H2O), 0.029 mL of 40 wt % hydrofluoric acid, and 2.56 g of 1-ethyl-3-methylimidazole hydroxide ([Emim]OH) were sequentially added to 8 mL of deionized water, and the mixture was stirred at 200 r / min at room temperature for 1 h. After stirring at 200 r / min for 0.1 h in an ice bath at 5°C, 5.8 mL of propylene oxide was added;

[0090] (2) A hydrogel was obtained by aging at 60°C for 2 h, and a xerogel was obtained by first drying at 120°C for 3 h. The molar ratio of MgO:Al2O3:P2O5:HF:(3-mercaptopropyl)trimethoxysilane:[Emim]OH:PO:H2O:Pt in the xerogel was 0.01:1.25:1.0:0.036:0.4:0.16:6.2:30.0:1.5×10 -5 ;

[0091] (3) The dry gel was placed in a stainless steel reactor lined with polytetrafluoroethylene and heated at 120°C for crystallization for 30 h. It was ultrasonically cleaned in a 150 W ultrasonic cleaner for 20 min, washed with water three times, dried for a second time at 100°C for 6 h, and then ground. After grinding, it was calcined at 400°C for 12 h in air atmosphere to obtain the Pt@MgAlPO-11 catalyst with AEL structure.

[0092] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing an aluminum phosphate molecular sieve encapsulated metal catalyst of an AEL structure, characterized in that: The steps include: (1) adding a metal solution Mo, (3-mercaptopropyl)trimethoxysilane, an aluminum source, phosphoric acid, a heteroatom M, hydrofluoric acid and a template agent to deionized water in sequence, stirring evenly at room temperature, stirring in an ice bath, and then adding propylene oxide; (2) Aging to obtain a hydrogel and first drying to obtain a xerogel; (3) heating the crystallized dry gel, ultrasonicating, washing with water to obtain a solid product, drying the solid product for a second time, grinding it, and calcining it to obtain an aluminum phosphate molecular sieve encapsulated metal catalyst powder with an AEL structure.

2. The method for preparing the aluminum phosphate molecular sieve encapsulated metal catalyst according to claim 1, characterized in that: In step (1), the metal-containing solution Mo is one of solutions containing Au, Pt, Pd, Ni, Ce, Cu, Ag or Rh, and the concentration of the metal-containing solution is 0.001-2 g / mL; the aluminum source is one of crystalline aluminum chloride, pseudo-boehmite, and aluminum isopropoxide; and the heteroatom M is one of Co, Cu, Fe, Mg, Ni, Si or Zn.

3. The method for preparing the aluminum phosphate molecular sieve encapsulated metal catalyst according to claim 1, characterized in that: In step (1), the template agent is one of diethylamine, di-n-propylamine, di-n-butylamine or 1-ethyl-3-methylimidazole hydroxide; the phosphoric acid concentration is 10-99wt%, and the hydrofluoric acid concentration is 5-70wt%; the room temperature stirring time is 0.5-5h; the ice bath stirring temperature is -5-5°C, and the ice bath stirring time is 0.1-1.5h.

4. The method for preparing the aluminum phosphate molecular sieve encapsulated metal catalyst according to claim 1, characterized in that: In the hydrogel of step (2), the molar ratio of M: Al2O3: P2O5: HF: (3-mercaptopropyl) trimethoxysilane: template: propylene oxide: H2O: Mo is 0.008-1.0: 0.10-5.0: 0.10-8.0: 0.005-0.5: 0.01-1.0: 0.025-3.0: 1.0-100: 5.0-500: 1.0×10 -8 ~1.0×10 -3 .

5. The method for preparing the aluminum phosphate molecular sieve encapsulated metal catalyst of the AEL structure according to claim 1, characterized in that: In step (2), the aging temperature is 50-90° C., and the aging time is 0.5-8 h; the first drying temperature is 60-120° C., and the first drying time is 2-24 h; the molar ratio of M:Al2O3:P2O5:HF:(3-mercaptopropyl)trimethoxysilane:template:propylene oxide:H2O:Mo in the dry gel is 0.008-1.0:0.10-5.0:0.10-8.0:0.005-0.5:0.01-1.0:0.025-3.0:1.0-100:5.0-50:1.0×10 -8 ~1.0×10 -3 .

6. The method for preparing the aluminum phosphate molecular sieve encapsulated metal catalyst of AEL structure according to claim 1, characterized in that: In step (3), the crystallization temperature is 80 to 240° C. and the crystallization time is 4 to 36 hours.

7. The method for preparing the aluminum phosphate molecular sieve encapsulated metal catalyst of AEL structure according to claim 1, characterized in that: In step (3), the temperature of the second drying is 50-120° C., and the second drying time is 2-24 hours; the power of the ultrasound is 50-350 W, and the time of the ultrasound is 5-30 minutes.

8. The method for preparing the aluminum phosphate molecular sieve encapsulated metal catalyst of AEL structure according to claim 1, characterized in that: In step (3), the calcination temperature is 400-600° C. and the calcination time is 2-12 hours.

9. An aluminum phosphate molecular sieve encapsulated metal catalyst with an AEL structure prepared by the method for preparing an aluminum phosphate molecular sieve encapsulated metal catalyst with an AEL structure as claimed in any one of claims 1 to 8.

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