Pt-based catalyst as well as preparation method and application thereof

Abstract

The invention provides a Pt-based catalyst and a preparation method and application thereof, and the preparation method comprises the following steps: 1) mixing NaOH, Al (OH) 3, water and silica sol to form a mixture A; 2) mixing a ligand-protected Pt precursor solution with the mixture A, stirring and aging to obtain a mixture B; 3) statically crystallizing the mixture B, cooling, centrifuging, washing, drying and roasting to obtain a solid; and 4) dipping the solid in a ligand-protected Pt precursor solution, and drying to obtain the Pt-based catalyst. By adopting a preparation mode of combining ligand-protected in-situ hydrothermal synthesis and a traditional impregnation method, the obtained catalyst has better reaction performance in catalysis of conversion of straight-chain alkanes into aromatic hydrocarbons, the reaction activity is obviously improved, the selectivity of small-molecule alkanes is greatly reduced, the selectivity of aromatic hydrocarbons is improved to 90% or above, and the catalyst has a better industrial application prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field of coal / petrochemical engineering, and particularly relates to a Pt-based catalyst, a preparation method thereof, and an application thereof. Background Art

[0002] The indirect coal liquefaction technology is an effective means to realize the efficient and clean utilization of coal resources and make up for the shortage of petroleum resources. However, the Fischer-Tropsch naphtha produced by this technology contains a large amount of straight-chain alkanes with low octane numbers, seriously affecting the quality of gasoline. The aromatization of straight-chain alkanes can convert low-octane straight-chain alkanes into high-octane aromatics, improving the quality of gasoline. Therefore, the development of alkane aromatization technology has received extensive attention in both the industrial and academic fields.

[0003] As the core of alkane aromatization technology, the catalyst is the key to affecting the operation of the aromatization unit. However, there are certain problems with currently commonly used alkane aromatization catalysts. For example, the bifunctional catalyst represented by commercial Pd / Al2O3 is prone to side reactions such as cracking and isomerization due to the presence of acidic sites, resulting in low selectivity of the target product. The monofunctional catalyst represented by Pt / KL can effectively avoid side reactions and exhibits excellent catalytic performance in the aromatization of C6 / C7 alkanes. However, when using C8 as the reaction raw material, the aromatization performance is significantly reduced and the stability is poor. Considering that long-chain alkanes are an important component of Fischer-Tropsch naphtha, it is urgent to study a highly efficient and stable catalyst suitable for the aromatization of medium- and long-chain alkanes. Summary of the Invention

[0004] In view of this, the object of the present invention is to provide a Pt-based catalyst, a preparation method thereof, and an application thereof. This method combines ligand-protected in-situ hydrothermal synthesis and traditional impregnation to prepare a catalyst in which the Pt active centers coexist in the form of Pt single atoms and sub-nanometer Pt clusters. Among them, the Pt single atoms can promote the dehydrogenation of alkanes into olefin intermediates, and the formed olefins are cyclized into aromatics on the surface of the sub-nanometer Pt clusters. The Pt single atoms and sub-nanometer Pt clusters synergistically catalyze the dehydrogenation cyclization of straight-chain alkanes into aromatics, thereby improving the reaction activity and aromatics selectivity of the catalyst.

[0005] The present invention provides a preparation method of a Pt-based catalyst, comprising the following steps:

[0006] 1) Mix NaOH, Al(OH)3, water, and silica sol to form mixture A;

[0007] 2) Mix the ligand-protected Pt precursor solution and mixture A, stir and then age to obtain mixture B;

[0008] 3) Crystallize mixture B statically, cool, centrifuge, wash, dry, and calcine to obtain a solid;

[0009] 4) Immerse the solid in a ligand-protected Pt precursor solution, and dry it to obtain a Pt-based catalyst.

[0010] Preferably, in step 1), the molar ratio of Na2O, Al2O3, SiO2 and deionized water in mixture A is (7.8 - 8.2):1:(8 - 12):(345 - 355).

[0011] Preferably, in step 2), the stirring time is 30 min to 2 h;

[0012] The aging time is 5 - 24 h.

[0013] Preferably, in step 3), the temperature of static crystallization is 98 - 180 °C, and the time is 10 - 24 h;

[0014] The drying temperature is 80 - 120 °C, and the time is 5 - 12 h;

[0015] The calcination temperature is 300 - 500 °C, and the time is 2 - 5 h.

[0016] Preferably, in step 4), the impregnation temperature is 30 - 65 °C, and the time is 2 - 8 h;

[0017] The drying temperature is 80 - 120 °C, and the time is 5 - 12 h.

[0018] Preferably, in steps 2) and 4), the Pt source of the ligand-protected Pt precursor is selected from platinum chloride and / or hexachloroplatinic acid; the ligands used include one or more of ethylenediamine, acetylacetone, and methylcyclopentadiene.

[0019] Preferably, the mass ratio of the ligand-protected Pt precursor solution in step 2) to the ligand-protected Pt precursor solution in step 4) is (1:5) - (5:1).

[0020] The present invention provides an application of a Pt-based catalyst prepared by the preparation method described in the above technical solution in the aromatization of C6 - C 10 linear alkanes.

[0021] Preferably, the reaction conditions for aromatization are: the reaction pressure is 0.1 - 0.5 MPa, the reaction temperature is 350 - 550 °C, the mass space velocity is 0.3 - 1.5 h -1 , and the molar ratio of H2 to linear alkanes is 5:1 - 10:1.

[0022] The present invention provides a method for preparing a Pt-based catalyst, comprising the following steps: 1) Mixing NaOH, Al(OH)3, water and silica sol to form a mixture A; 2) Mixing a ligand-protected Pt precursor solution and the mixture A, aging after stirring to obtain a mixture B; 3) Subjecting the mixture B to static crystallization, centrifuging, washing, drying and calcining after cooling to obtain a solid; 4) Impregnating the solid in a ligand-protected Pt precursor solution and drying to obtain the Pt-based catalyst. The present invention adopts a preparation method combining ligand-protected in-situ hydrothermal synthesis and traditional impregnation method. The obtained catalyst has excellent reaction performance in catalyzing the conversion of linear alkanes into aromatics, with significantly improved reaction activity and a substantial reduction in the selectivity of small-molecule alkanes. The selectivity of aromatics is increased to more than 90%, having excellent industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 HAADF-STEM of the Pt-based catalyst prepared in Example 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] The present invention provides a method for preparing a Pt-based catalyst, comprising the following steps:

[0025] 1) Mixing NaOH, Al(OH)3, water and silica sol to form a mixture A;

[0026] 2) Mixing a ligand-protected Pt precursor solution and the mixture A, aging after stirring to obtain a mixture B;

[0027] 3) Subjecting the mixture B to static crystallization, centrifuging, washing, drying and calcining after cooling to obtain a solid;

[0028] 4) Impregnating the solid in a ligand-protected Pt precursor solution and drying to obtain the Pt-based catalyst.

[0029] The present invention adopts a preparation method combining ligand-protected in-situ hydrothermal synthesis and traditional impregnation method. The obtained catalyst has excellent reaction performance in catalyzing the conversion of linear alkanes into aromatics, with significantly improved reaction activity and a substantial reduction in the selectivity of small-molecule alkanes. The selectivity of aromatics is increased to more than 90%, having excellent industrial application prospects.

[0030] The present invention mixes NaOH, Al(OH)3, water and silica sol to form mixture A. During the mixing process of NaOH, Al(OH)3, water and silica sol, a silica-alumina sol is formed, which is mixture A; the molar ratio of Na2O, Al2O3, SiO2 and deionized water in mixture A is (7.8 - 8.2):1:(8 - 12):(345 - 355); in specific embodiments, the molar ratio of Na2O, Al2O3, SiO2 and deionized water is 8:1:10:350.

[0031] After obtaining mixture A, the present invention mixes the ligand-protected Pt precursor solution and the mixture A, stirs and then ages to obtain mixture B. In the present invention, the stirring time is 30 min to 2 h, specifically 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min or 120 min. The aging time is 5 - 24 h; specifically 5 h, 5.5 h, 6.0 h, 6.5 h, 7.0 h, 7.5 h, 8.0 h, 8.5 h, 9.0 h, 9.5 h, 10. h, 10.5 h, 11 h, 11.5 h, 12 h, 12.5 h, 13 h, 13.5 h, 4 h, 14.5 h, 15 h, 15.5 h, 16 h, 16.5 h, 17 h, 17.5 h, 18 h, 18.5 h, 19 h, 19.5 h, 20 h, 20.5 h, 21 h, 21.5 h, 22 h, 22.5 h, 23 h, 23.5 h or 24 h.

[0032] In the present invention, the Pt source of the ligand-protected Pt precursor is selected from platinum chloride and / or hexachloroplatinic acid; the ligands used include one or more of ethylenediamine, acetylacetone and methylcyclopentadiene. In specific embodiments, the Pt source is a hexachloroplatinic acid solution with a concentration of 0.04 mol / L; the ligand is ethylenediamine or methylcyclopentadiene.

[0033] The ligand-protected Pt precursor solution in the present invention is preferably prepared by the following method: mixing the Pt source and the ligand to obtain the ligand-protected Pt precursor solution. The Pt source is in the form of a solution; such as a hexachloroplatinic acid solution. The mixing is carried out under stirring conditions; the mixing is carried out at room temperature; the mixing time is 8 - 13 min, preferably 9 - 10 min.

[0034] After obtaining mixture B, the present invention statically crystallizes the mixture B, cools it, then centrifuges, washes, dries and calcines it to obtain a solid.

[0035] In the present invention, the static crystallization is carried out in a hydrothermal autoclave; the temperature of the static crystallization is 98 - 180 °C and the time is 10 - 24 h.

[0036] After static crystallization, it is cooled, centrifuged, washed, dried and calcined after cooling to room temperature to obtain a solid; the drying temperature is 80-120 °C and the time is 5-12 h; specifically, the drying temperature is 80 °C, 85 °C, 90 °C, 95 °C, 100 °C, 105 °C, 110 °C, 115 °C or 120 °C; the time is 5 h, 5.5 h, 6.0 h, 6.5 h, 7.0 h, 7.5 h, 8.0 h, 8.5 h, 9.0 h, 9.5 h, 10. h, 10.5 h, 11 h, 11.5 h or 12 h.

[0037] In the present invention, the calcination temperature is 300-500 °C and the time is 2-5 h; specifically, the calcination temperature is 300 °C, 310 °C, 320 °C, 330 °C, 340 °C, 350 °C, 360 °C, 370 °C, 380 °C, 390 °C, 400 °C, 410 °C, 420 °C, 430 °C, 440 °C, 450 °C, 460 °C, 470 °C, 480 °C, 490 °C or 500 °C; the time is 2 h, 2.5 h, 3.0 h, 3.5 h, 4.0 h, 4.5 h or 5 h. Under the above calcination temperature and time, the ligand of the Pt source in the solid is completely calcined and decomposed.

[0038] After obtaining the solid, the present invention impregnates the solid in a Pt precursor solution protected by a ligand and dries it to obtain a Pt-based catalyst. In the present invention, the impregnation temperature is 30-65 °C and the time is 2-8 h; specifically, the impregnation temperature is 30 °C, 35 °C, 40 °C, 45 °C, 50 °C, 55 °C, 60 °C or 65 °C, and the time is 2 h, 2.5 h, 3.0 h, 3.5 h, 4.0 h, 4.5 h, 5.0 h, 5.5 h, 6.0 h, 6.5 h, 7.0 h, 7.5 h or 8 h. After impregnation, it is dried, and the drying temperature is 80-120 °C and the time is 5-12 h; specifically, the drying temperature is 80 °C, 85 °C, 90 °C, 95 °C, 100 °C, 105 °C, 110 °C, 115 °C or 120 °C; the time is 5 h, 5.5 h, 6.0 h, 6.5 h, 7.0 h, 7.5 h, 8.0 h, 8.5 h, 9.0 h, 9.5 h, 10. h, 10.5 h, 11 h, 11.5 h or 12 h.

[0039] The Pt-based catalyst is a Pt-based catalyst in which part of the Pt is protected by a ligand; the ligand in the Pt-based catalyst will be gradually decomposed with the reduction of the metal in the reaction pre-reduction stage (referring to before the reaction liquid material is put into the reaction tube).

[0040] The present invention adopts a method combining ligand-protected in-situ hydrothermal synthesis and traditional impregnation to load the Pt source, which is beneficial to constructing a catalyst with the coexistence of Pt single atoms and sub-nano Pt clusters. Among them, the Pt loaded by in-situ hydrothermal synthesis aggregates during the reduction process due to the loss of ligand protection after high-temperature calcination and is encapsulated in the molecular sieve cage in the form of sub-nano by the molecular sieve; the Pt loaded by the traditional impregnation method can avoid aggregation during the reduction process to a certain extent due to ligand protection and exists in the form of Pt single atoms.

[0041] In step 2) of the present invention, the mass ratio of the ligand-protected Pt precursor solution to the ligand-protected Pt precursor solution in step 4) is (1:5) to (5:1). In specific embodiments, the mass ratio of the ligand-protected Pt precursor solution in step 2) to the ligand-protected Pt precursor solution in step 4) is 1:5; or 1:1; or 5:1; or 2:1.

[0042] The present invention also provides an application of the Pt-based catalyst prepared by the preparation method described in the above technical solution in the aromatization of C6-C 10 linear alkanes.

[0043] In the present invention, the reaction conditions for aromatization are: the reaction pressure is 0.1-0.5 MPa, the reaction temperature is 350-550 °C, the mass space velocity is 0.3-1.5 h -1 , and the molar ratio of H2 to linear alkanes is 5:1 to 10:1.

[0044] In the present invention, the Pt species of the Pt-based catalyst coexist in the form of sub-nano Pt clusters and Pt single atoms. The Pt single atoms can promote the dehydrogenation of alkanes into olefin intermediates, and the formed olefin intermediates are cyclized into aromatics on the surface of the sub-nano Pt clusters. The synergistic effect of the sub-nano Pt clusters and Pt single atoms greatly improves the aromatization reaction activity of linear alkanes, reduces the selectivity of small-molecule alkanes (C1-C4), and exhibits excellent aromatization performance of linear alkanes.

[0045] In order to further illustrate the present invention, the following examples are used to describe in detail a Pt-based catalyst, its preparation method and application provided by the present invention, but they should not be construed as limiting the protection scope of the present invention.

[0046] Example 1

[0047] 1. Weigh 4.5 g of NaOH, 1.0 g of Al(OH)3 and 36 g of deionized water in a 100 mL beaker, stir at room temperature until clear, and then dropwise add the above mixture to 9 g of silica sol and stir evenly to obtain a silica-alumina sol.

[0048] 2. Weigh 1.2 g of hexachloroplatinic acid solution (0.04 mol / L) and 0.3 mL of ethylenediamine solution, and stir them at room temperature for 10 min to obtain a ligand-protected Pt source.

[0049] 3. Weigh 0.2 g of the ligand-protected Pt source and slowly add it dropwise to the silica-alumina sol system. Stir at room temperature for 30 min and then age for 24 h. Subsequently, transfer it to a 100 mL hydrothermal autoclave and carry out static crystallization at 100 °C for 24 h. After crystallization is completed, centrifuge and wash it until neutral, and dry it at 80 °C for 12 h. Then place it in a muffle furnace at 300 °C and calcine it for 5 h.

[0050] 4. Take 1.0 g of the ligand-protected Pt source and add it to the above-mentioned calcined solid. Immerse it at 30 °C for 8 h and then dry it at 80 °C for 12 h. After drying is completed, a Pt-based catalyst with some Pt protected by ligands is obtained.

[0051] Figure 1 The HAADF-STEM of the Pt-based catalyst prepared in Example 1 of the present invention is shown. It can be seen that the Pt species in the Pt-based catalyst coexist as Pt single atoms and sub-nanometer Pt clusters.

[0052] Example 2

[0053] 1. Weigh 4.5 g of NaOH, 1.0 g of Al(OH)3 and 36 g of deionized water in a 100 mL beaker, stir at room temperature until clear, and then add the above mixture dropwise to 9 g of silica sol and stir evenly to obtain a silica-alumina sol.

[0054] 2. Weigh 1.2 g of hexachloroplatinic acid solution (0.04 mol / L) and 0.3 mL of ethylenediamine solution, and stir them at room temperature for 10 min to obtain a ligand-protected Pt source.

[0055] 3. Weigh 0.6 g of the ligand-protected Pt source and slowly add it dropwise to the silica-alumina sol system. Stir at room temperature for 1 h and then age for 15 h. Subsequently, transfer it to a 100 mL hydrothermal autoclave and carry out static crystallization at 140 °C for 18 h. After crystallization is completed, centrifuge and wash it until neutral, and dry it at 100 °C for 9 h. Then place it in a muffle furnace at 400 °C and calcine it for 3 h.

[0056] 4. Take 0.6 g of the ligand-protected Pt source and add it to the above-mentioned calcined solid. Immerse it at 45 °C for 5 h and then dry it at 100 °C for 9 h. After drying is completed, a Pt-based catalyst with some Pt protected by ligands is obtained.

[0057] Example 3

[0058] 1. Weigh 4.5 g of NaOH, 1.0 g of Al(OH)3 and 36 g of deionized water into a 100 mL beaker, stir until clear at room temperature, and then add the above mixture dropwise to 9 g of silica sol, stir evenly to obtain silica-alumina sol.

[0059] 2. Weigh 1.2 g of hexachloroplatinic acid solution (0.04 mol / L) and 0.3 mL of ethylenediamine solution, stir at room temperature for 10 min to obtain a ligand-protected Pt source.

[0060] 3. Weigh 1.0 g of the ligand-protected Pt source and slowly add it dropwise to the silica-alumina sol system, stir at room temperature for 2 h and then age for 5 h. Subsequently, transfer it to a 100 mL hydrothermal autoclave and carry out static crystallization at 180 °C for 12 h. After crystallization is completed, centrifuge and wash it to neutral, dry it at 120 °C for 6 h, and then place it in a muffle furnace at 500 °C and calcine it for 2 h.

[0061] 4. Take 0.2 g of the ligand-protected Pt source and add it to the above calcined solid, impregnate it at 60 °C for 2 h and then dry it at 120 °C for 6 h. After drying is completed, a Pt-based catalyst with part of the Pt protected by the ligand is obtained.

[0062] Example 4

[0063] 1. Weigh 4.5 g of NaOH, 1.0 g of Al(OH)3 and 36 g of deionized water into a 100 mL beaker, stir until clear at room temperature, and then add the above mixture dropwise to 9 g of silica sol, stir evenly to obtain silica-alumina sol.

[0064] 2. Weigh 1.2 g of hexachloroplatinic acid solution (0.04 mol / L) and 0.42 mL of methylcyclopentadiene solution, stir at room temperature for 10 min to obtain a ligand-protected Pt source.

[0065] 3. Weigh 0.8 g of the ligand-protected Pt source and slowly add it dropwise to the silica-alumina sol system, stir at room temperature for 2 h and then age for 5 h. Subsequently, transfer it to a 100 mL hydrothermal autoclave and carry out static crystallization at 180 °C for 12 h. After crystallization is completed, centrifuge and wash it to neutral, dry it at 120 °C for 6 h, and then place it in a muffle furnace at 500 °C and calcine it for 2 h.

[0066] 4. Take 0.4 g of the ligand-protected Pt source and add it to the above calcined solid, impregnate it at 60 °C for 2 h and then dry it at 120 °C for 6 h. After drying is completed, a Pt-based catalyst with part of the Pt protected by the ligand is obtained.

[0067] Comparative Example 1

[0068] 1. Weigh 4.5 g of NaOH, 1.0 g of Al(OH)₃ and 36 g of deionized water into a 100 mL beaker, stir at room temperature until clear, and then add the above mixture dropwise to 9 g of silica sol, stir evenly to obtain silica-alumina sol.

[0069] 2. Weigh 1.2 g of hexachloroplatinic acid solution (0.04 mol / L) and 0.3 mL of ethylenediamine solution, stir at room temperature for 10 min to obtain a ligand-protected Pt source.

[0070] 3. Weigh 1.2 g of the ligand-protected Pt source and slowly add it dropwise to the silica-alumina sol system, stir at room temperature for 2 h and then age for 6 h. Subsequently, transfer it to a 100 mL hydrothermal autoclave and carry out static crystallization at 100 °C for 12 h. After crystallization is completed, centrifuge and wash it until neutral, dry it at 80 °C for 12 h, and then place it in a muffle furnace at 400 °C and calcine it for 3 h to obtain the Pt-based catalyst.

[0071] Comparative Example 2

[0072] 1. Weigh 4.5 g of NaOH, 1.0 g of Al(OH)₃ and 36 g of deionized water into a 100 mL beaker, stir at room temperature until clear, and then add the above mixture dropwise to 9 g of silica sol, stir evenly to obtain silica-alumina sol. Subsequently, transfer it to a 100 mL hydrothermal autoclave and carry out static crystallization at 100 °C for 12 h. After crystallization is completed, centrifuge and wash it until neutral, dry it at 80 °C for 12 h, and then place it in a muffle furnace at 400 °C and calcine it for 3 h.

[0073] 2. Weigh 1.2 g of hexachloroplatinic acid solution (0.04 mol / L) and 0.3 mL of ethylenediamine solution, stir at room temperature for 10 min to obtain a ligand-protected Pt source.

[0074] 3. Take 1.2 g of the ligand-protected Pt source and add it to the above calcined solid, impregnate it at room temperature for 2 h and then dry it at 80 °C for 12 h. After drying is completed, obtain the ligand-protected Pt-based catalyst with Pt.

[0075] Test Example

[0076] Using n-octane as the model reactant, evaluate the aromatization performance of the above-prepared catalyst. Mix 0.5 g of the prepared Pt-based catalyst with quartz sand and load it into a fixed-bed reaction tube, reduce it at 500 °C for 1 h at a H₂ gas flow rate of 50 mL / min. After reduction is completed, lower the temperature of the reaction tube to the reaction temperature and adjust the H₂ flow rate to 8 mL / min. Subsequently, turn on the liquid feed pump with a liquid flow rate of 0.8 mL / h. The product (react online for 10 h) enters the online gas chromatography through a 200 °C heating belt for component analysis after being kept warm, as shown in Table 1 for details.

[0077] Table 1 Evaluation results of the catalytic performance of the catalysts in the examples and comparative examples

[0078]

[0079] Among them, C8= represents octene (olefin molecules with 8 carbon atoms such as 1-octene / 2-octene).

[0080] As can be seen from the above examples, the present invention provides a method for preparing a Pt-based catalyst, comprising the following steps: 1) mixing NaOH, Al(OH)3, water and silica sol to form mixture A; 2) mixing the ligand-protected Pt precursor solution and the mixture A, aging after stirring to obtain mixture B; 3) statically crystallizing the mixture B, centrifuging, washing, drying and calcining after cooling to obtain a solid;

[0081] 4) impregnating the solid in the ligand-protected Pt precursor solution, drying to obtain a Pt-based catalyst. The Pt-based catalyst prepared by this method is a Pt-based catalyst in which part of Pt is protected by a ligand, and the ligand will be gradually decomposed as the metal is reduced during the reaction pre-reduction stage to obtain a Pt-based catalyst. In the present invention, the Pt species of the Pt-based catalyst coexist in the form of sub-nanometer Pt clusters and Pt single atoms. The Pt single atoms can promote the dehydrogenation of alkanes into olefin intermediates, and the formed olefin intermediates are cyclized into aromatics on the surface of the sub-nanometer Pt clusters. The synergistic effect of the sub-nanometer Pt clusters and Pt single atoms greatly improves the aromatization reaction activity of linear alkanes and reduces the selectivity of small-molecule alkanes (C1-C4), showing excellent aromatization performance of linear alkanes.

[0082] The above is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A preparation method of a Pt-based catalyst, comprising the following steps: 1) Mix NaOH, Al(OH)3, water and silica sol to form mixture A; 2) Mix the ligand-protected Pt precursor solution and the mixture A, stir and then age to obtain mixture B; 3) Subject the mixture B to static crystallization, cool, centrifuge, wash, dry and calcine to obtain a solid; 4) Immerse the solid in the ligand-protected Pt precursor solution and dry to obtain the Pt-based catalyst.

2. The preparation method according to claim 1, characterized in that, In step 2), the stirring time is 30 min to 2 h; the aging time is 5 to 24 h.

3. The preparation method according to claim 1, wherein In step 3), the temperature of static crystallization is 98 to 180 °C and the time is 10 to 24 h; The drying temperature is 80 to 120 °C and the time is 5 to 12 h; The calcination temperature is 300 to 500 °C and the time is 2 to 5 h.

4. The preparation method according to claim 1, wherein In step 1), the molar ratio of Na2O, Al2O3, SiO2 and deionized water in mixture A is (7.8 to 8.2):1:(8 to 12):(345 to 355).

5. The preparation method according to claim 1, characterized in that, In step 4), the impregnation temperature is 30 to 65 °C and the time is 2 to 8 h; the drying temperature is 80 to 120 °C and the time is 5 to 12 h.

6. The preparation method according to claim 1, characterized in that, In steps 2) and 4), the Pt source used for the ligand-protected Pt precursor is selected from platinum chloride and / or hexachloroplatinic acid; the ligands used include one or more of ethylenediamine, acetylacetone and methylcyclopentadiene.

7. The preparation method according to claim 1, characterized in that, In step 2), the mass ratio of the ligand-protected Pt precursor solution to the ligand-protected Pt precursor solution in step 4) is (1:5) to (5:1).

8. A Pt-based catalyst prepared by the preparation method according to any one of claims 1 to 7.

9. Use of a Pt-based catalyst prepared by the preparation method according to any one of claims 1 to 7 in the aromatization of C6-C 10 linear alkanes.

10. The application according to claim 9, wherein The reaction conditions for aromatization are as follows: the reaction pressure is 0.1 - 0.5 MPa, the reaction temperature is 350 - 550 °C, and the mass space velocity is 0.3 - 1.5 h -1 , and the molar ratio of H2 to linear alkane is 5:1 - 10:1.

Images