Preparation method and application of metal embedded multi-level pore SAPO-56 zeolite molecular sieve

Abstract

The present invention relates to a preparation method and application of a metal-embedded hierarchical pore SAPO-56 zeolite molecular sieve, which includes the following process: pseudoboehmite is used as the aluminum source, 85% wt phosphoric acid aqueous solution is used as the phosphorus source, silica gel is used as the silicon source, and copper oxalate metal precursor is used. The raw materials are added according to the molar ratio of Al2O3:H2O:P2O5:SiO2:CuO = 0.8:60:0.8:1.0:(0.8-1.2). After adding and stirring evenly in sequence, hydrothermal crystallization reaction is carried out at 160-210 °C for 48-96 h. After taking out the product, it is washed with water until neutral and dried, and then calcined at 550 °C for 5 h to obtain a hierarchical pore SAPO-56 zeolite molecular sieve with a metal-embedded structure. The crystallinity of the obtained product is ≥93%, the specific surface area is 458 m 2 / g, the pore size distribution is at 11 nm, the actual content of metallic Cu is 3.5%, and the dispersion degree of elemental Cu after reduction is 33.7%. The present invention does not require an organic mesoporous template agent, the product has high crystallinity, and it can directly synthesize a hierarchical pore zeolite catalyst containing embedded metal species, which is applied to the reaction of hydrogenation of CO2 to methanol, and has high catalytic activity, stability and target product selectivity.

Description

Technical Field

[0001] The invention relates to the technical field of zeolite molecular sieve synthesis, and in particular to a preparation method and application of a metal embedded multi-level pore SAPO-56 zeolite molecular sieve. Background Art

[0002] SAPO-56 zeolite molecular sieve is an aluminum phosphate molecular sieve with AFX topological structure, which has a three-dimensional octahedral pore structure and a pore size of 0.34nm×0.36nm. Its surface is acidic and can be used as a catalyst, ion exchanger, and adsorbent for separation and purification of molecules. Therefore, it has attracted wide attention in the fields of industrial catalysis, adsorption separation, and ion exchange.

[0003] However, the smaller pore size of SAPO-56 zeolite molecular sieve is more difficult to process compounds with larger molecular structures and more complex compositions, so it is necessary to introduce a multi-level pore structure to improve its performance in practical applications. At present, regarding the synthesis of multi-level pore structure zeolite molecular sieves, long-chain aminosilanes are generally used as organic templates or potassium hydroxide is used as inorganic directing agents. However, the synthesis process of the organic template itself is complicated and expensive, while potassium hydroxide is too alkaline and easily causes reactor corrosion, and both of them cause serious environmental pollution, which not only leads to higher zeolite production costs, but also does not conform to the green, environmentally friendly and sustainable development trend of today's society.

[0004] Therefore, the present invention attempts to develop a synthesis strategy for a multi-level porous SAPO-56 zeolite molecular sieve without using an organic template or a strong alkaline inorganic structure directing agent, and the obtained zeolite sample has a special metal embedded structure and can be directly used in various catalytic reactions, truly achieving both high efficiency and economy and green environmental protection. Summary of the invention

[0005] How to synthesize SAPO-56 zeolite molecular sieve with high crystallinity and hierarchical pore structure without using organic mesoscopic templates and strong alkaline inorganic structure directing agents is the key technical problem to be solved by the present invention. The SAPO-56 zeolite molecular sieve synthesized by the method of the present invention not only has high crystallinity and hierarchical pore structure, but also introduces embedded metal species, which can be directly used as a catalyst and applied to CO2 hydrogenation conversion reaction, and has high catalytic activity and stability as well as target product selectivity.

[0006] In order to achieve the above objectives, the present invention is implemented through the following technical solutions:

[0007] The preparation method of metal-embedded multi-level pore SAPO-56 zeolite molecular sieve comprises the following steps: using pseudo-boehmite as an aluminum source, using an 85%wt phosphoric acid aqueous solution as a phosphorus source, using silica gel as a silicon source, and using a copper oxalate metal precursor, adding them in sequence and stirring them evenly, and then performing a hydrothermal crystallization reaction at 160-210°C for 48-96h, taking out the product, washing it with water to neutrality, drying it, and calcining it at 550°C for 5h to obtain the metal-embedded multi-level pore SAPO-56 zeolite molecular sieve;

[0008] The aluminum source, the phosphorus source, the silicon source and the metal precursor in the system are calculated by the raw material feeding amount of Al2O3, P2O5, SiO2 and M2O, and are added according to the molar ratio of Al2O3:H2O:P2O5:SiO2:M2O=0.8:60:0.8:0.8:(0.8-1.2).

[0009] Furthermore, the order of adding the metal precursor in the system is after silica gel.

[0010] Furthermore, the temperature of the hydrothermal crystallization reaction is 200° C. and the time is 72 hours.

[0011] The last aspect of the present invention provides the metal-embedded multi-level pore SAPO-56 zeolite molecular sieve obtained by the above preparation method, and the metal-embedded multi-level pore SAPO-56 zeolite molecular sieve is made into a catalyst for use in the CO2 hydrogenation conversion process.

[0012] Furthermore, the transition metal is one of Fe, Co, Ni, Cu, Zn, Mn, Zr, La, and Ce, and preferably the transition metal is Cu.

[0013] Beneficial technical effects: The present invention uses silica gel as a silicon source, and under the action of a copper oxalate metal precursor, hydrothermal crystallization directly synthesizes a high-crystallinity SAPO-56 zeolite molecular sieve with a multi-level pore structure. Compared with the prior art, without using a small molecule organic template, the problem of corrosion of the reactor by using strong alkaline substances such as potassium hydroxide is overcome, and an environmentally friendly and low-cost synthesis route is found. And the obtained high-crystallinity SAPO-56 zeolite molecular sieve with a multi-level pore structure can be directly used as a CO2 hydrogenation conversion catalyst, which can effectively catalyze CO2 conversion. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a SEM image of the metal-embedded multi-level pore SAPO-56 zeolite molecular sieve prepared in Example 1;

[0015] Figure 2 The N2 adsorption-desorption isotherm and pore size distribution curve of the metal-embedded multi-level pore SAPO-56 zeolite molecular sieve prepared in Example 1;

[0016] Figure 3 XRD patterns of SAPO-56 zeolite molecular sieves synthesized under different metal conditions in Examples 1 to 9; wherein a represents Fe2O3, b represents CoO, c represents NiO, d represents CuO, e represents ZnO, f represents MnO, g represents La2O3, h represents ZrO2, and i represents CeO2;

[0017] Figure 4 XRD patterns of SAPO-56 zeolite molecular sieves synthesized with different metal precursors in Examples 10 and 11 and Comparative Example 4; wherein a represents copper nitrate, b represents copper acetylacetonate, and c represents copper oxalate;

[0018] Figure 5 XRD patterns of the products synthesized under different Al2O3:M2O ratios in Examples 12 to 15 and Comparative Example 4; wherein a represents Al2O3:M2O=0.8:0.8, b represents Al2O3:M2O=0.8:0.9, c represents Al2O3:M2O=0.8:1, d represents Al2O3:M2O=0.8:1.1, and e represents Al2O3:M2O=0.8:1.2;

[0019] Figure 6 XRD patterns of SAPO-56 zeolite molecular sieves synthesized in different addition orders of metal precursors in Examples 16 and 17 and Comparative Example 4; wherein a represents post-addition of pseudo-boehmite, b represents post-addition of phosphoric acid, and c represents post-addition of silica gel;

[0020] Figure 7 XRD patterns of SAPO-56 zeolite molecular sieves synthesized under different crystallization temperature reactions in Examples 18 to 22 and Comparative Example 4; wherein a represents 160° C., b represents 170° C., c represents 180° C., d represents 190° C., e represents 200° C., and f represents 210° C.;

[0021] Figure 8 XRD patterns of SAPO-56 zeolite molecular sieves synthesized under different crystallization reaction times in Examples 23 to 26 and Comparative Example 4; wherein a represents 48h, b represents 60h, c represents 72h, d represents 84h, and e represents 96h;

[0022] Fig. 9 is a catalytic activity diagram of each catalyst for carbon dioxide conversion in Application Example 1;

[0023] Fig.10 XRD diagrams of SAPO-56 zeolite molecular sieves synthesized by different synthesis methods: a represents comparative example 7-1, b represents comparative example 7-2, and c represents comparative example 1-4;

[0024] Table 1 shows the preparation parameters and crystallinity of the examples and the products of the examples. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present invention will be described clearly and completely below in combination with the embodiments of the present invention and the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. All other embodiments obtained by ordinary technicians in this field without creative work based on the embodiments of the present invention are within the scope of protection of the present invention.

[0026] Unless otherwise specifically stated, the numerical value set forth in these embodiments does not limit the scope of the present invention. The technology and method known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology and method should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values.

[0027] The experimental methods in the following examples without specifying specific conditions are usually measured according to national standards; if there is no corresponding national standard, it is carried out according to the general international standards or the standard requirements proposed by relevant enterprises. Unless otherwise specified, all parts are by weight and all percentages are by weight.

[0028] In the following examples and the expression "the molar ratio of each material Al2O3:H2O:P2O5:SiO2:M2O" in the examples, Al2O3 refers to an aluminum source, and the molar number of the aluminum source is the molar number of the aluminum element in pseudo-boehmite, SiO2 refers to a silicon source, and the molar number of the silicon source is the molar number of the silicon element in silica gel, and M2O (M element is iron, cobalt, nickel, copper, zinc, manganese, zirconium, lanthanum or cerium element) refers to a metal source, and the molar number of the metal source is the molar number of iron, cobalt, nickel, copper, zinc, manganese, zirconium, lanthanum or cerium in iron oxalate, cobalt oxalate, nickel oxalate, copper oxalate, zinc oxalate, manganese oxalate, zirconium oxalate, lanthanum oxalate and cerium oxalate.

[0029] Test and calculation method of crystallinity (%): The crystallinity is tested using an X-ray diffractometer, and the calculation formula is: crystallinity = (diffraction peak intensity / total intensity) * 100%, and jade software is used for data processing.

[0030] SBET was measured by nitrogen adsorption using a physical adsorption instrument.

[0031] Example 1

[0032] Weigh 3 g of pseudo-boehmite and dissolve it in 15 mL of H2O. Add 3.8 mL of 85% wt phosphoric acid aqueous solution to the above solution, add 1.38 g of silica gel, stir for 30 min, and then add 0.104 g / mL of Fe2C6O dropwise. 12 The solution was stirred for 30 minutes, and then the obtained mixture was put into a high-pressure reactor and placed in an oven at 200°C for hydrothermal crystallization for 72 hours; the product obtained by the reaction was filtered, washed, dried, and calcined at 550°C for 5 hours. The molar ratio of each raw material in the system is 0.8:60:1.0:0.8:1.0 with Al2O3:H2O:P2O5:SiO2:Fe2O3. The crystallinity of the obtained SAPO-56 zeolite is shown in Table 1.

[0033] Example 2

[0034] The preparation method of SAPO-56 zeolite in this embodiment is the same as that in Example 1-1, except that the metal precursor solution is a 0.074 g / mL CoC2O4 solution.

[0035] Example 3

[0036] The preparation method of SAPO-56 zeolite in this embodiment is the same as that in Example 1-1, except that the metal precursor solution is a 0.074 g / mL NiC2O4 solution.

[0037] Example 4

[0038] The preparation method of SAPO-56 zeolite in this embodiment is the same as that in Example 1-1, except that the metal precursor solution is a 0.072 g / mL CuC2O4 solution.

[0039] Example 5

[0040] The preparation method of SAPO-56 zeolite in this embodiment is the same as that in Example 1-1, except that the metal precursor solution is a 0.07 g / mL ZnC2O4 solution.

[0041] Example 6

[0042] The preparation method of SAPO-56 zeolite in this embodiment is the same as that in Example 1-1, except that the metal precursor solution is a 0.078 g / mL MnC2O4 solution.

[0043] Example 7

[0044] The preparation method of SAPO-56 zeolite in this embodiment is the same as that in Example 1-1, except that the metal precursor solution is a 0.056 g / mL La2(C2O4)3 solution.

[0045] Example 8

[0046] The preparation method of SAPO-56 zeolite in this embodiment is the same as that in Example 1-1, except that the metal precursor solution is a 0.09 g / mL Zr(C2O4)2 solution.

[0047] Example 9

[0048] The preparation method of SAPO-56 zeolite in this embodiment is the same as that in Example 1-1, except that the metal precursor solution is a 0.056 g / mL Ce2(C2O4)3 solution.

[0049] Example 10

[0050] The preparation method of SAPO-56 zeolite in this example is the same as that of Comparative Examples 1-4, except that the metal precursor solution is a 0.115 g / mL copper nitrate solution.

[0051] Embodiment 11

[0052] The preparation method of SAPO-56 zeolite in this example is the same as that of Comparative Examples 1-4, except that the metal precursor solution is a 0.124 g / mL copper acetylacetonate solution.

[0053] Example 12

[0054] Weigh 3g of pseudo-boehmite and dissolve it in 15mL H2O. Add 3.8mL of 85%wt phosphoric acid aqueous solution to the above solution, add 1.38g of silica gel, stir for 30min, add 0.058g / mL of CuC2O4 solution dropwise, stir for 30min, and then put the obtained mixture into a high-pressure reactor and place it in a 200℃ oven for hydrothermal crystallization for 72h; filter, wash, and dry the product obtained by the reaction, and then calcine it at 550℃ for 5h. The molar ratio of each raw material in the system is 0.8:60:1.0:0.8:0.8 as Al2O3:H2O:P2O5:SiO2:CuO. The crystallinity of the obtained SAPO-56 zeolite is shown in Table 1.

[0055] Example 13

[0056] The preparation method of SAPO-56 zeolite in this example is the same as that in Example 3-1, except that the concentration of the CuC2O4 solution is 0.065 g / mL. The molar ratio of each material in the system is 0.8:60:1.0:0.8:0.9, with Al2O3:H2O:P2O5:SiO2:CuO.

[0057] Embodiment 14

[0058] The preparation method of SAPO-56 zeolite in this example is the same as that in Example 2-1, except that the concentration of the CuC2O4 solution is 0.079 g / mL. The molar ratio of each material in the system is 0.8:60:1.0:0.8:1.1, i.e., Al2O3:H2O:P2O5:SiO2:CuO.

[0059] Embodiment 15

[0060] The preparation method of SAPO-56 zeolite in this example is the same as that in Example 2-1, except that the concentration of the CuC2O4 solution is 0.086 g / mL. The molar ratio of each material in the system is 0.8:60:1.0:0.8:1.2, i.e., Al2O3:H2O:P2O5:SiO2:CuO.

[0061] Example 16

[0062] The preparation method of the metal embedded multi-level pore SAPO-56 zeolite molecular sieve of this embodiment is the same as that of Embodiments 1-4, except that the copper oxalate solution is added after the pseudo-boehmite solution.

[0063] Embodiment 17

[0064] The preparation method of the metal embedded multi-level pore SAPO-56 zeolite molecular sieve of this embodiment is the same as that of Embodiments 1-4, except that the copper oxalate solution is added after the phosphoric acid.

[0065] Embodiment 18

[0066] The preparation method of the metal embedded multi-level pore SAPO-56 zeolite molecular sieve of this embodiment is the same as that of Comparative Examples 1-4, except that the hydrothermal crystallization reaction temperature is 160°C.

[0067] Embodiment 19

[0068] The preparation method of the metal embedded multi-level pore SAPO-56 zeolite molecular sieve of this embodiment is the same as that of Comparative Examples 1-4, except that the hydrothermal crystallization reaction temperature is 170°C.

[0069] Embodiment 20

[0070] The preparation method of the metal embedded multi-level pore SAPO-56 zeolite molecular sieve of this embodiment is the same as that of Comparative Examples 1-4, except that the hydrothermal crystallization reaction temperature is 180°C.

[0071] Embodiment 21

[0072] The preparation method of the metal embedded multi-level pore SAPO-56 zeolite molecular sieve of this embodiment is the same as that of Comparative Examples 1-4, except that the hydrothermal crystallization reaction temperature is 190°C.

[0073] Embodiment 22

[0074] The preparation method of the metal embedded multi-level pore SAPO-56 zeolite molecular sieve of this embodiment is the same as that of Comparative Examples 1-4, except that the hydrothermal crystallization reaction temperature is 210°C.

[0075] Embodiment 23

[0076] The preparation method of the metal embedded multi-level pore SAPO-56 zeolite molecular sieve of this embodiment is the same as that of Comparative Examples 1-4, except that the hydrothermal crystallization reaction time is 48 hours.

[0077] Embodiment 24

[0078] The preparation method of the metal embedded multi-level pore SAPO-56 zeolite molecular sieve in this embodiment is the same as that of Comparative Examples 1-4, except that the hydrothermal crystallization reaction time is 60 hours.

[0079] Embodiment 25

[0080] The preparation method of the metal embedded multi-level pore SAPO-56 zeolite molecular sieve of this embodiment is the same as that of Comparative Examples 1-4, except that the hydrothermal crystallization reaction time is 84 hours.

[0081] Embodiment 26

[0082] The preparation method of the metal embedded multi-level pore SAPO-56 zeolite molecular sieve of this embodiment is the same as that of Comparative Examples 1-4, except that the hydrothermal crystallization reaction time is 96 hours.

[0083] Table 1

[0084]

[0085] The XRD patterns of SAPO-56 zeolite molecular sieves synthesized under different metal sources in Examples 1 to 9 above are as follows: Figure 3 As shown, a represents Fe2O3, b represents CoO, c represents NiO, d represents CuO, e represents ZnO, f represents MnO, g represents La2O3, h represents ZrO2, and i represents CeO2.

[0086] Depend on Figure 3 As shown in Table 1, Comparative Example 4 obtained SAPO-56 with a crystallinity of 99.12%.

[0087] XRD patterns of SAPO-56 zeolite molecular sieves synthesized in different addition orders of metal precursors in Examples 10 and 11 and Comparative Example 4 above. Where a represents the addition after pseudo-boehmite, b represents the addition after phosphoric acid, and c represents the addition after silica gel. Fig.10As shown in Table 1, the order of adding the metal precursors has an effect on the crystallinity. When the metal precursors are added after the silica gel, the crystallinity is best achieved at 99.12%.

[0088] XRD patterns of SAPO-56 zeolite molecular sieves synthesized under different Al2O3:M2O ratios in Examples 12 to 15 and Comparative Example 4 above; wherein a represents Al2O3:M2O=0.8:0.8, b represents Al2O3:M2O=0.8:0.9, c represents Al2O3:M2O=0.8:1, d represents Al2O3:M2O=0.8:1.1, and e represents Al2O3:M2O=0.8:1.2. Figure 4 As shown in Table 1, SAPO-56 has a high crystallinity of more than 83%.

[0089] The XRD patterns of the SAPO-56 zeolite molecular sieves synthesized under different crystallization temperature reactions in the above Examples 18 to 22 and Comparative Example 4 are as follows: Figure 8 As shown in the table; a represents 160℃, b represents 170℃, c represents 180℃, d represents 190℃, e represents 200℃, and f represents 210℃. Figure 8 As shown in Table 1, the crystallization reaction at 160-210°C can obtain SAPO-56 with a crystallinity of more than 83%.

[0090] The XRD patterns of the SAPO-56 zeolite molecular sieves synthesized under different crystallization reaction times in the above Examples 23 to 26 and Comparative Example 4 are as follows: Fig. 9 As shown in the table; a represents 48h, b represents 60h, c represents 72h, d represents 84h, and e represents 96h. Fig. 9 As shown in Table 1, a SAPO-56 zeolite molecular sieve with a crystallinity of more than 89% can be obtained by reacting at 200°C for 48-80h. As the reaction time increases, the crystallinity reaches 99.12% at 72h, and the crystallinity remains basically unchanged after 72h.

[0091] Comparative Example 27: Preparation of conventional microporous SAPO-56 zeolite molecular sieve

[0092] Weigh 3g pseudo-boehmite and dissolve it in 20mL H2O. After stirring thoroughly, add 3.8mL 85%wt phosphoric acid aqueous solution to the above solution, add 1.03g silica gel, stir for 30min, add 12MLN,N,N,N-tetramethyl-1,6-hexanediamine (TMHD) dropwise, stir overnight at room temperature, put the obtained mixture into a high-pressure reactor, place it in an oven at 210℃ for hydrothermal crystallization for 95h; filter, wash and dry the product obtained by the reaction, and dry the solid product at 100℃ overnight. Calcinate at 550℃ for 8h. The molar ratio of each raw material in the system is 0.8:40:1.0:0.6:2.0 for Al2O3:H2O:P2O5:SiO2:TMHD. The texture properties of the obtained microporous SAPO-56 are shown in Table 2.

[0093] Comparative Example 28: Preparation of hierarchical pore SAPO-56 zeolite molecular sieve using inorganic structure directing agent

[0094] The use of inorganic structure directing agents to prepare hierarchical SAPO-56 zeolite has been reported in relevant patents and literatures, with KOH as the inorganic structure directing agent. For this purpose, we will prepare a synthetic hierarchical SAPO-56 zeolite molecular sieve using KOH as an inorganic structure directing agent. The preparation method is as follows: weigh 3g of pseudo-boehmite and dissolve it in 20mL H2O. After sufficient stirring, add 3.8mL of 85%wt phosphoric acid aqueous solution to the above solution, add 1.38g of silica gel, stir for 30min, add 30mL of 0.94mol / mL KOH solution dropwise, and stir for another 30min. Then, put the obtained mixture into a high-pressure reactor and place it in an oven at 210℃ for hydrothermal crystallization for 72h; filter, wash, and dry the product obtained by the reaction, and then calcine it at 560℃ for 6h. The molar ratio of each raw material in the system is 0.8:60:1:0.8:1 for Al2O3:H2O:P2O5:SiO2:Na2O. The texture properties of the prepared multi-level porous SAPO-56 are shown in Table 2.

[0095] Comparative Examples 27 and 28 were set to compare the SAPO-56 zeolite molecular sieves synthesized by different synthesis methods. The SAPO-56 zeolites prepared in Comparative Examples 4, 27, and 28 were subjected to XRD tests. The obtained XRD patterns are shown in Fig.10 ,Through the crystallinity and XRD patterns in Table 2, we can see that SAPO-56 zeolite molecular sieve can be synthesized using TMHD as a template, but no mesopores are generated.

[0096] Table 2 Organization structure of SAPO-56 prepared by different synthesis methods

[0097]

[0098] Application Example 1

[0099] The metal-embedded multi-level pore SAPO-56 zeolite molecular sieves of Example 1 (amorphous), Example 2 (71.34%), Example 3 (54.31%), Example 4 (99.12%), Example 5 (80.21%), Example 6 (amorphous), Example 7 (88.12%), Example 8 (amorphous), and Example 9 (84.37%) are applied to the reaction of hydrogenating carbon oxides to prepare alcohol compounds, specifically, the reaction of hydrogenating carbon dioxide to prepare methanol.

[0100] When the crystallinity of SAPO-56 exceeds 89%, the influence on the carbon dioxide conversion rate is minimal.

[0101] The metal embedded multi-level porous SAPO-56 zeolite molecular sieve catalyst has a specific preparation process: a certain amount of pseudo-boehmite is weighed and dissolved in deionized water, and a certain amount of 85%wt phosphoric acid solution and silica gel are added in sequence after stirring evenly, and a copper oxalate ligand solution is added dropwise after stirring evenly, and then the mixture is fully stirred and hydrothermally crystallized at 200°C for 72h. The system composition is Al2O3:H2O:P2O5:SiO2:CuC2O4=0.8:60:1.0:0.8:1.0. The product obtained by the reaction is filtered, washed, and dried, and then calcined at 550°C for 5h to obtain a 3%Cu / SAPO-56 molecular sieve catalyst.

[0102] In addition, 3.5% Cu / SAPO-56, 3.5% Fe / SAPO-56, 3.5% Co / SAPO-56, 3.5% Ni / SAPO-56, 3.5% Zn / SAPO-56, 3.5% Mn / SAPO-56, 3.5% La / SAPO-56, 3.5% Zr / SAPO-56, and 3.5% Ce / SAPO-56 were also prepared according to the above method.

[0103] The catalytic activity of the above catalysts on carbon dioxide was tested. The conversion rate of carbon dioxide catalyzed by the catalysts was as follows: Fig. 9 As shown in the left figure. Fig. 9 As can be seen from the left figure, 3.5% Cu / SAPO-56 has the highest catalytic CO2 conversion rate and the best selectivity among single metal catalysts.

[0104] At the same time, the activity of 3.5% Cu / SAPO-56 and commercial traditional precious metal-loaded Pt-Al2O3 catalyst, traditional commercial catalyst CuO-ZnO-Al2O3, MoS2, and Ni-HLSX catalyst (CN202110379122.6) for catalytic CO2 hydrogenation to methanol was also compared. The results are as follows Fig. 9 As shown in the right figure, Fig. 9As can be seen from the right figure, the Pt-Al2O3 catalyst has the highest CO2 conversion rate, and after long-term use, it still has the highest conversion rate among all catalysts. The conversion rate of 3% Cu / SAPO-56 is slightly lower than that of the precious metal-loaded Pt-Al2O3 catalyst, but significantly higher than that of traditional commercial catalysts Ni-HLSX, CuO-ZnO-Al2O3 and MoS2, and it does not deactivate after long-term use.

[0105] The catalyst prepared by the present invention using SAPO-56 with a high crystallinity multi-level pore structure as a carrier to load a transition metal can enable the catalyst to work continuously for 1000 hours without significantly decreasing the catalytic efficiency, and has good industrial application stability and catalytic activity.

[0106] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing a metal embedded multi-level pore SAPO-56 zeolite molecular sieve, characterized in that: The method comprises the following steps: using pseudo-boehmite as an aluminum source, an 85%wt phosphoric acid aqueous solution as a phosphorus source, silica gel as a silicon source, and copper oxalate as a metal precursor, adding the four raw materials in sequence, stirring evenly, and then performing hydrothermal crystallization at 160-210°C for 48-96h, taking out the product, washing it with water to neutrality, drying it, and calcining it at 550°C for 5h to obtain a multi-level porous SAPO-56 zeolite molecular sieve with a metal embedded structure; The aluminum source, the phosphorus source, the silicon source and the metal precursor in the system are calculated by the raw material feeding amount of Al2O3, P2O5, SiO2 and CuO, and are added according to the molar ratio of Al2O3:H2O:P2O5:SiO2:CuO=0.8:60:(0.6-1.2):0.8:1.

0.

2. The preparation method according to claim 1, characterized in that: The aluminum source, the phosphorus source, the silicon source and the metal precursor in the system are calculated with the raw material feeding amount of Al2O3, P2O5, SiO2 and CuO, and are replaced according to the molar ratio of Al2O3:H2O:P2O5:SiO2:CuO=0.8:60:1.0:0.8:(0.8-1.2).

3. The preparation method according to claim 1, characterized in that: The temperature of the hydrothermal crystallization reaction is 200° C. and the time is 72 hours.

4. Application of metal embedded multi-level pore SAPO-56 zeolite molecular sieve, characterized in that: The multi-level porous SAPO-56 zeolite molecular sieve with a metal embedded structure obtained by the preparation method of the metal embedded multi-level porous SAPO-56 zeolite molecular sieve described in any one of claims 1 to 3 is used as a catalyst.

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