Preparation method and application of ultrastrong-stability Pt-based light alkane dehydrogenation catalyst

Abstract

The invention discloses a preparation method and application of a superstrong-stability low-carbon alkane dehydrogenation catalyst. The catalyst is composed of a molecular sieve carrier, a main active metal Pt, and auxiliary active metals Zn, Cu, Ga, Ge and Ce. Firstly, a molecular sieve carrier is subjected to high-temperature activation treatment, and then auxiliary metal and main active metal are sequentially pulsed to the surface of the activated molecular sieve carrier by adopting an atomic layer deposition method. According to the method, surface hydroxyl enrichment of the molecular sieve is induced through high-temperature thermal activation treatment, a high-density hydroxyl anchoring site is directionally constructed, then the size of active metal is regulated and controlled at the atomic scale through the ALD technology, sub-nano-scale dispersion of precious metal Pt and auxiliary metal is achieved, and the stable nano-catalyst with strong metal-carrier interaction is formed. The catalyst can react for more than 1200 hours at a high temperature for a long time, and the performance of the catalyst is not obviously inactivated. The comprehensive preparation method provides reliable technical support for optimizing the catalytic performance, and becomes a general strategy for preparing a high-performance catalyst.

Description

Technical Field

[0001] The present invention relates to the field of industrial catalyst preparation, and in particular to a preparation method and application of a super-stable Pt-based low-carbon alkane dehydrogenation catalyst. Background Art

[0002] Olefins, as chemical intermediates and industrial raw materials, are widely used in the production of products such as polyolefins, and market demand continues to grow. Traditional production methods, such as naphtha steam cracking and catalytic cracking of light diesel, have seen declining olefin yields, prompting the catalytic dehydrogenation of light alkanes to become an emerging technology. This catalytic dehydrogenation technology efficiently converts resources such as light alkanes into high-value olefins while producing high-value hydrogen as a byproduct. Compared to traditional methods, it is more environmentally sustainable and lays the foundation for green and efficient olefin production.

[0003] In the field of light alkane dehydrogenation, Pt-based catalysts are the mainstream catalysts. Their outstanding performance, high activity, and low pollution have made them a research hotspot in recent years. However, industrial dehydrogenation processes often operate at high temperatures (>600°C), and Pt-based catalysts are commonly susceptible to carbon deposition and poor stability, leading to rapid catalyst deactivation. To restore catalytic activity, Pt-based catalysts are frequently regenerated. This regeneration process not only involves calcination to remove carbon but also requires redispersion of the Pt species, significantly increasing production costs and economic benefits. Calcination to remove carbon releases CO₂, which is detrimental to environmental sustainability. Redispersion of the Pt species uses Cl₂, which is highly corrosive and can pose a threat to equipment and pipelines, leading to premature aging and damage. Neither of these methods meets the urgent demands for environmental friendliness and sustainable development. Therefore, there is an urgent need to develop highly efficient and extremely stable Pt-based catalysts for light alkane dehydrogenation.

[0004] In recent years, research on low-carbon alkane dehydrogenation catalysts has continued in-depth, and numerous methods for preparing the catalysts have been developed. CN201611010754.0 discloses a propane dehydrogenation catalyst prepared by a coprecipitation method and a preparation method thereof. The catalyst uses CaO-Al2O3 composite oxide pellets as a carrier and metal Pt as an active component. The catalyst exhibits excellent reaction performance and carbon deposition resistance. CN201910729420.6 discloses an in-situ hydrothermal crystallization method for preparing a propane dehydrogenation catalyst, a preparation method thereof, and applications thereof. The catalyst comprises a molecular sieve carrier, Pt and Zn active components, and the resulting PtZn catalyst. CN202211690361.4 discloses a Pt-based catalyst with a bimetallic oxide as a carrier, a preparation method, and an application thereof. The catalyst uses ZrO2-Al2O3 bioxide as a carrier and Pt as an active component. The ZrO2-Al2O3 bioxide carrier is first prepared by precipitation crystallization, and the obtained carrier is then impregnated in a Pt solution, dried, and calcined to obtain a Pt-based catalyst. CN202310313996.0 discloses a Pt-based dehydrogenation catalyst for the reaction of dehydrogenating propane to produce propylene using a step-by-step impregnation method, a preparation method, and an application thereof. The auxiliary component and the active component containing the Pt element are successively loaded on the Al2O3 carrier to obtain a Pt-based dehydrogenation catalyst. The above patents have made great improvements in the preparation of highly active propane dehydrogenation catalysts, but the high-temperature reaction stability needs to be strengthened, especially during the ultra-high temperature reaction process, where the activity decreases too quickly.

[0005] Based on this, the present invention provides a preparation method and application of a super-stable low-carbon alkane dehydrogenation catalyst. Summary of the Invention

[0006] The purpose of the present invention is to solve the problems of low high-temperature reaction activity, low selectivity and poor stability of existing Pt-based catalysts for the dehydrogenation of light alkanes to olefins under high-temperature reaction conditions. This patent provides the preparation and application of a low-carbon alkane dehydrogenation catalyst with super stability: an activated molecular sieve is used as a carrier, Pt element is used as the main active metal, and also includes a first auxiliary active metal and a first auxiliary active metal. By activating the molecular sieve carrier at high temperature, highly enriched hydroxyl sites are directionally constructed. On this basis, combined with ALD technology, the growth strategy of the self-limiting surface hydroxyl chemical reaction of the molecular sieve carrier is utilized to achieve single-atom-level dispersed Pt clusters fixed-point anchoring to form a stable nanocatalyst with strong metal-carrier interaction. Compared with the traditional impregnation method, this preparation method can not only further optimize the high dispersion and high purity of multiple active metals in the catalyst, but also obtain metal nanoclusters with accurate structure and accurate composition, so that the catalyst has more stable catalytic activity.

[0007] To achieve the above object, the present invention adopts the following technical solutions: A super-stable Pt-based low-carbon alkane dehydrogenation catalyst, wherein the catalyst carrier is a molecular sieve, the main active metal component is Pt element, and the auxiliary metal active component is any one of Zn, Cu, Ga, Ge and Ce elements; based on the total mass of the catalyst, the content of the molecular sieve is 1.00-99.00 wt%, the loading amount of the main active metal component Pt is 0.01-1.00 wt%, and the loading amount of the auxiliary metal active component is 0.01-1.00 wt%; the catalyst is prepared using ALD technology and a growth strategy of self-limiting chemical reaction on the molecular sieve surface.

[0008] The present invention also provides a method for preparing the above-mentioned ultra-stable Pt-based light alkane dehydrogenation catalyst, which specifically comprises the following steps: (1) First, the molecular sieve support is activated by high-temperature heat treatment to expose the surface hydroxyl active sites; (2) Place the activated molecular sieve carrier into the reaction chamber of the atomic layer deposition instrument; (3) Pulsing the additive metal compound onto the surface of the molecular sieve support; (4) re-pulsing the main active metal Pt compound to deposit on the surface of the molecular sieve support to obtain a catalyst precursor; (5) The catalyst precursor obtained in step (4) is reduced at high temperature under an inert gas atmosphere to obtain a catalyst.

[0009] Furthermore, the temperature of the high temperature heat treatment method in step (1) is 100-1000°C, the time is 1-100 hours, and the activation atmosphere is any one of N2, H2 and O2 or a mixture of several thereof.

[0010] Furthermore, the molecular sieve in step (2) is any one of S-1, Beta, and ZSM-5, or a mixture of several of them.

[0011] Furthermore, the auxiliary metal compound in step (3) is any one of diethylzinc (DEZn), copper acetylacetonate (Cu(hfac)2), trimethylgallium (TMGa), cerium acetylacetonate (Ce(acac)4) and cerium trimesic acid (Ce-BTC) or a mixture of several of them.

[0012] Furthermore, the main active metal Pt compound in step (4) is any one of methylcyclopentadienyltrimethylplatinum (MeCpPtMe3), acetylacetonate platinum (Pt(acac)2), dinitrodiammineplatinum (Pt(NO3)2(NH3)2) or a mixture thereof.

[0013] Furthermore, the inert gas in step (5) is any one of Ar, He and N2 or a mixture of several of them.

[0014] Furthermore, the temperature of the atomic layer deposition method in steps (3) and (4) is 100 to 1000°C, and the number of cycles is 10 to 1000 times.

[0015] Furthermore, the reduction temperature in step (5) is 100-900° C., and the reduction time is 1-100 h.

[0016] The present invention also provides application of a Pt-based low-carbon alkane dehydrogenation catalyst with super stability at high temperature in direct dehydrogenation of propane to produce propylene.

[0017] Taking propane dehydrogenation reaction as an example, the following process conditions need to be followed; (1) forming the Pt-based catalyst into 20-60 mesh granular catalysts; (2) Weigh a certain mass of Pt-based catalyst and mix it evenly with 2 g of quartz sand (20-80 mesh) and then fill it into a fixed-bed reactor with an inner diameter of 12 mm quartz tube. Keep the catalyst in the constant temperature range of the device's heating furnace. (3) The catalyst is first pretreated with H2 for a period of time, then cooled to room temperature; then the temperature is raised to the propane dehydrogenation temperature at a rate of 2 °C / min; a certain amount of pure propane reaction gas is passed through the catalyst bed to carry out catalytic dehydrogenation reaction.

[0018] Furthermore, the mass of the loaded Pt-based catalyst in step (2) is 0.01 to 1.00 g; the pure propane gas is industrial propane; Furthermore, the H2 pretreatment temperature in step (3) is 100-1000°C; the reduction time is 1-100h; Furthermore, the reaction temperature in step (3) is 100-1000°C; Furthermore, the propane flow rate in step (3) is 10-100 mL / min, and the mass space velocity of propane is WHSV=4-1000 h -1 .

[0019] The beneficial effects of the present invention are: The present invention provides the preparation and application of a highly stable catalyst for the dehydrogenation of light alkanes. The catalyst is characterized by using an activated molecular sieve as a carrier, using ALD to introduce the main active metal (Pt) and an auxiliary active metal, and then calcining and reducing at high temperature to obtain a Pt-based catalyst. High-temperature thermal activation treatment is first used to induce surface hydroxyl enrichment of the molecular sieve, directionally constructing a defect network structure with high-density vacancies and coordinatively unsaturated sites, and then using atomic layer deposition technology to control the deposition of the active metal at the atomic scale, achieving subnanometer-scale dispersion of the precious metal Pt, and forming a stable nanocatalyst with strong metal-support interaction. The catalyst can react at high temperatures for long periods of time exceeding 1200 hours without significant deactivation of its performance. Overall, the combination of high-temperature activated molecular sieves and ALD leverages the advantages of multiple catalyst preparation methods to improve the activity, selectivity, and long-term stability of Pt-based catalysts. This catalyst preparation method has broad application prospects in the field of industrial catalysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the STEM image of the PtCe / S-1 (ALD) catalyst obtained in Example 1.

[0021] Figure 2 This is the STEM image of the PtCe / S-1(IM) catalyst obtained in Comparative Example 1.

[0022] Figure 3 The long-term catalytic performance of the PtCe / S-1 (ALD) catalyst obtained in Example 1; reaction conditions: temperature 650 °C, raw material: 100% C3H8, propane mass space velocity WHSV = 8.0 h -1 . DETAILED DESCRIPTION

[0023] In order to better understand the technical solution of the present invention, the following is a further detailed description with reference to specific embodiments and drawings, but this does not limit the scope of protection of the present invention.

[0024] Unless otherwise specified, the drugs used in the following examples were purchased commercially and were not processed. Pure silicon MFI molecular sieve (S-1), MFI molecular sieve (ZSM-5), BEA molecular sieve (Beta), diethylzinc (DEZn), cerium acetylacetonate (Ce(acac)4), and methylcyclopentadienyltrimethylplatinum (MeCpPtMe3) were purchased from Aladdin Reagent Co., Ltd. Deionized water used in the experiments was obtained from the laboratory's high-purity water system.

[0025] The catalysts in the examples are named PtM / ZSM-5, where Pt represents the primary active metal component and M represents the additive active metal component. For example, a catalyst containing Pt and Ce species deposited by atomic layer deposition on a ZSM-5 support is designated PtCe / ZSM-5 (ALD).

[0026] Comparative Example 1 (Immersion Method) (1) Weigh 4.0 g of S-1 molecular sieve carrier and set aside; (2) Weigh 50.0 mg of H2PtCl6·6H2O and 30.0 mg of CeCl2 and dissolve them in 2.0 g of deionized water. Stir in a 30 °C water bath for 1.0 h to form a homogeneous solution. (3) slowly impregnating the homogeneous solution obtained in step (2) onto the S-1 molecular sieve support; (4) The mixed sample obtained in step (3) was placed in an oven at 100 °C for 6.0 h, and then placed in a muffle furnace for calcination at 600 °C for 24 h to obtain a PtCe / S-1 catalyst precursor.

[0027] (5) The PtCe / S-1 catalyst precursor was placed in a high-purity H2 atmosphere in a tubular furnace, heated to 600 °C at a rate of 2.0 °C / min and maintained for 2.0 h to obtain the PtCe / S-1(IM) catalyst (Pt = 0.47 wt%, Ce = 0.50 wt%).

[0028] Comparative Example 2 (Immersion Method) (1) Weigh 4.0 g of ZSM-5 molecular sieve carrier and set aside; (2) Weigh 50.0 mg of H2PtCl6·6H2O and 30.0 mg of CeCl2 and dissolve them in 2.0 g of deionized water. Stir in a 30 °C water bath for 1.0 h to form a homogeneous solution. (3) slowly impregnating the uniform solution obtained in step (2) onto the ZSM-5 support; (4) The mixed sample obtained in step (3) was placed in an oven at 100 °C for 6.0 h, and then calcined in a muffle furnace at 600 °C for 24 h to obtain a PtCe / ZSM-5 catalyst precursor.

[0029] (5) The PtCe / ZSM-5 catalyst precursor was placed in a high-purity H2 atmosphere in a tubular furnace, heated to 600 °C at a rate of 2.0 °C / min and maintained for 2.0 h to obtain the PtCe / ZSM-5 (IM) catalyst (Pt = 0.47 wt%, Ce = 0.50 wt%).

[0030] Comparative Example 3 (Immersion Method) (1) Weigh 4.0 g of Beta molecular sieve carrier and set aside; (2) Weigh 50.0 mg of H2PtCl6·6H2O and 30.0 mg of CeCl2 and dissolve them in 2.0 g of deionized water. Stir in a 30 °C water bath for 1.0 h to form a homogeneous solution. (3) Slowly impregnating the homogeneous solution obtained in step (2) onto the Beta support; (4) The mixed sample obtained in step (3) was placed in an oven at 100 °C for 6.0 h, and then calcined in a muffle furnace at 600 °C for 24 h to obtain a PtCe / Beta catalyst precursor.

[0031] (5) The PtCe / Beta catalyst precursor was placed in a high-purity H2 atmosphere in a tubular furnace, heated to 600 °C at a rate of 2.0 °C / min and maintained for 2.0 h to obtain a PtCe / Beta (IM) catalyst (Pt = 0.47 wt%, Ce = 0.50 wt%).

[0032] Example 1 (1) First, weigh 4.0 g of S-1 molecular sieve and treat it in an O2 atmosphere at 600 °C for 5 h to obtain an activated molecular sieve carrier; (2) Place the activated S-1 molecular sieve carrier into the reaction chamber and disperse it evenly; (3) At 300 °C, the first precursor, 0.16 g of cerium acetylacetonate (Ce(acac)4), was pulsed and cycled 100 times to uniformly disperse it on the surface of the molecular sieve. (4) Pulsing the second precursor 0.33 g of methylcyclopentadienyltrimethylplatinum (MeCpPtMe3) for 150 cycles to uniformly disperse it on the surface of the molecular sieve to obtain the PtCe / S-1 (ALD) catalyst precursor; (5) The PtCe / S-1(ALD) catalyst precursor was placed in a high-purity H2 atmosphere in a tubular furnace, heated to 700 °C at a rate of 2.0 °C / min and maintained for 5.0 h, finally obtaining the PtCe / S-1(ALD) catalyst (Pt = 0.47 wt%, Ce = 0.50 wt%).

[0033] Example 2 (1) First, weigh 4.0 g of ZSM-5 molecular sieve and treat it in an O2 atmosphere at 600 °C for 5 h to obtain an activated molecular sieve carrier; (2) Place the activated ZSM-5 molecular sieve carrier into the reaction chamber and disperse it evenly; (3) At 300 °C, the first precursor, 0.16 g of cerium acetylacetonate (Ce(acac)4), was pulsed and cycled 100 times to uniformly disperse it on the surface of the molecular sieve. (4) Pulsing the second precursor 0.33 g of methylcyclopentadienyltrimethylplatinum (MeCpPtMe3) and cycling it 150 times to uniformly disperse it on the surface of the molecular sieve to obtain the PtCe / ZSM-5 (ALD) catalyst precursor; (5) The PtCe / ZSM-5 (ALD) catalyst precursor was placed in a high-purity H2 atmosphere in a tubular furnace, heated to 700 °C at a rate of 2.0 °C / min and maintained for reduction for 5.0 h, finally obtaining the PtCe / ZSM-5 (ALD) catalyst (Pt = 0.47 wt%, Ce = 0.50 wt%).

[0034] Example 3 (1) First, weigh 4.0 g of Beta molecular sieve and treat it in an O2 atmosphere at 600 °C for 5 h to obtain an activated molecular sieve carrier; (2) Place the activated Beta molecular sieve carrier into the reaction chamber and disperse it evenly; (3) At 300 °C, the first precursor, 0.16 g of cerium acetylacetonate (Ce(acac)4), was pulsed and cycled 100 times to uniformly disperse it on the surface of the molecular sieve. (4) Pulsing the second precursor 0.33 g of methylcyclopentadienyltrimethylplatinum (MeCpPtMe3) and circulating it 150 times to uniformly disperse it on the surface of the molecular sieve to obtain the PtCe / Beta (ALD) catalyst precursor; (5) The PtCe / Beta(ALD) catalyst precursor was placed in a high-purity H2 atmosphere in a tubular furnace, heated to 700 °C at a rate of 2.0 °C / min and maintained for 5.0 h to obtain the PtCe / Beta(ALD) catalyst (Pt = 0.47 wt%, Ce = 0.50 wt%).

[0035] Example 4 (1) First, weigh 4.0 g of S-1 molecular sieve and treat it in an O2 atmosphere at 600 °C for 5 h to obtain an activated molecular sieve carrier; (2) Place the activated S-1 molecular sieve carrier into the reaction chamber and disperse it evenly; (3) At 300 °C, the first precursor, 0.038 g of diethylzinc (DEZn), was pulsed and cycled 100 times to uniformly disperse it on the surface of the molecular sieve; (4) Pulsing the second precursor 0.33 g of methylcyclopentadienyltrimethylplatinum (MeCpPtMe3) and cycling it 150 times to uniformly disperse it on the surface of the molecular sieve to obtain the PtZn / S-1 (ALD) catalyst precursor; (5) The PtZn / S-1(ALD) catalyst precursor was placed in a high-purity H2 atmosphere in a tubular furnace, heated to 700 °C at a rate of 2.0 °C / min and maintained for 5.0 h, finally obtaining the PtZn / S-1(ALD) catalyst (Pt = 0.47 wt%, Zn = 0.50 wt%).

[0036] Example 5 (1) First, weigh 4.0 g of ZSM-5 molecular sieve and treat it in an O2 atmosphere at 600 °C for 5 h to obtain an activated molecular sieve carrier; (2) Place the activated ZSM-5 molecular sieve carrier into the reaction chamber and disperse it evenly; (3) At 300 °C, the first precursor, 0.038 g of diethylzinc (DEZn), was pulsed and cycled 100 times to uniformly disperse it on the surface of the molecular sieve; (4) Pulsing the second precursor 0.33 g of methylcyclopentadienyltrimethylplatinum (MeCpPtMe3) and cycling it 150 times to uniformly disperse it on the surface of the molecular sieve to obtain the PtZn / ZSM-5 (ALD) catalyst precursor; (5) The PtZn / ZSM-5 (ALD) catalyst precursor was placed in a high-purity H2 atmosphere in a tubular furnace, heated to 700 °C at a rate of 2.0 °C / min and maintained for reduction for 5.0 h, finally obtaining the PtZn / ZSM-5 (ALD) catalyst (Pt = 0.47 wt%, Zn = 0.50 wt%).

[0037] Example 6 (1) First, weigh 4.0 g of Beta molecular sieve and treat it in an O2 atmosphere at 600 °C for 5 h to obtain an activated molecular sieve carrier; (2) Place the activated Beta molecular sieve carrier into the reaction chamber and disperse it evenly; (3) At 300 °C, the first precursor, 0.038 g of diethylzinc (DEZn), was pulsed and cycled 100 times to uniformly disperse it on the surface of the molecular sieve; (4) Pulsing the second precursor 0.33 g of methylcyclopentadienyltrimethylplatinum (MeCpPtMe3) and cycling it 150 times to uniformly disperse it on the surface of the molecular sieve to obtain the PtZn / Beta (ALD) catalyst precursor; (5) The PtZn / Beta(ALD) catalyst precursor was placed in a high-purity H2 atmosphere in a tubular furnace, heated to 700 °C at a rate of 2.0 °C / min and maintained for 5.0 h to obtain the PtZn / Beta(ALD) catalyst (Pt = 0.47 wt%, Zn = 0.50 wt%).

[0038] The high-temperature catalytic reaction performances of different Pt-based catalysts obtained in the Examples and Comparative Examples are shown in Table 1.

[0039] The specific process conditions are as follows: (1) forming the above-mentioned Pt-based catalyst into 40-mesh strip-shaped granular catalyst; (2) Weigh 0.2 g of Pt-based catalyst and 2 g of quartz sand (40 mesh) and mix them evenly. Then fill the fixed bed reactor with a quartz tube with an inner diameter of 12 mm and keep the catalyst in the constant temperature range of the device heating furnace. (3) The catalyst was pretreated with H2 at 700 °C for 2 h, then cooled to room temperature; then the temperature was raised to the propane dehydrogenation temperature at a rate of 2 °C / min; a certain amount of pure propane reaction gas was passed through the catalyst bed to carry out the catalytic dehydrogenation reaction (WHSV = 8 h -1 ).

[0040] Table 1 Comparison of high-temperature catalytic performance of different Pt-based catalysts

[0041] Note: Reaction conditions: temperature 650 °C, raw material: 100% C3H8, propane mass space velocity WHSV = 8.0 h -1 .

[0042] The catalytic performance results in Table 1 demonstrate that the Pt-based catalysts of Examples 1-6 (atomic layer deposition) exhibit significantly improved high-temperature stability compared to the catalysts of Comparative Examples 1-3 (impregnation). Furthermore, the catalysts maintain excellent propane conversion and propylene selectivity at high temperatures (>600°C), with virtually no change in catalyst deactivation. The Pt-based catalyst prepared by combining an activated molecular sieve support with atomic layer deposition (ALD) exhibits an initial propane conversion of approximately 56.5% and a propylene selectivity of approximately 97.2% at 650°C in pure propane. These performances show no significant decline over a reaction time exceeding 1000 hours. In contrast, the Pt-based catalyst prepared by the traditional impregnation method (Comparative Example 1) exhibits an initial propane conversion of 50.5% and a propylene selectivity of 95.4%. However, after only 48 hours of reaction, its propane conversion drops to 24.5% and its propylene selectivity to 90.1%, demonstrating a significant downward trend in stability. The above comparative experimental results show that the Pt-based catalyst prepared by combining high-temperature activated molecular carriers and atomic layer deposition method has high propane conversion rate and high propylene selectivity under ultra-high temperature conditions (650 ℃), and most importantly, greatly improves the long-term stability of the catalyst.

[0043] Figure 1 and Figure 2 The STEM images of PtCe / S-1 (IM) and PtCe / S-1 (ALD) are respectively, and the Pt metal particle sizes are 3.1 and 0.9 nm, respectively, indicating that the metal particles on the surface of the catalyst prepared by combining high-temperature activation of the support and atomic layer deposition are smaller and more evenly dispersed. Figure 3 The catalyst performance graph for the PtCe / S-1(ALD) catalyst shows no significant decline in catalytic performance after a high-temperature reaction time of over 1200 h, demonstrating excellent high-temperature stability. The above demonstrates that the introduction of active metals onto a molecular sieve support via atomic layer deposition (ALD) achieves superior high-temperature propane dehydrogenation catalytic performance. This catalyst preparation method facilitates a more uniform dispersion of the active component Pt and the promoter species on the catalyst surface, thereby increasing the number of active sites and effectively enhancing the reaction activity. Furthermore, this catalyst preparation method prevents excessive aggregation of metal particles and agglomeration between particles, thereby maintaining a uniform distribution of the Pt element and significantly improving the high-temperature stability of the catalyst. A comprehensive comparison with similar Pt-based propane dehydrogenation catalysts shows that this preparation method significantly surpasses the catalytic performance of currently reported catalysts, providing strong support for the future design and application of high-temperature catalysts.

[0044] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. A highly stable Pt-based catalyst for dehydrogenation of light alkanes, characterized by: The catalyst carrier is a molecular sieve, the main active metal component is Pt element, and the auxiliary metal active component is any one of Zn, Cu, Ga, Ge and Ce elements; based on the total mass of the catalyst, the content of the molecular sieve is 1.00-99.00 wt%, the loading amount of the main active metal component Pt is 0.01-1.00 wt%, and the loading amount of the auxiliary metal active component is 0.01-1.00 wt%; the catalyst is prepared by atomic layer deposition using the growth technology of self-limiting chemical reaction on the surface of the molecular sieve.

2. The method for preparing the ultra-stable Pt-based light alkane dehydrogenation catalyst according to claim 1, wherein: The specific steps include: (1) First, the molecular sieve support is activated by high-temperature heat treatment to expose the hydroxyl active sites on the surface of the molecular sieve support; (2) Place the activated molecular sieve carrier into the reaction chamber of the atomic layer deposition instrument; (3) The pulse-assisted metal compound is deposited on the surface of the molecular sieve support; (4) re-pulsing the main active metal Pt compound for secondary deposition on the surface of the molecular sieve support to obtain a catalyst precursor; (5) The catalyst precursor obtained in step (4) is reduced at high temperature under an inert gas atmosphere to obtain a catalyst.

3. The preparation method according to claim 2, wherein: The temperature of the high temperature heat treatment method in step (1) is 100-1000°C, the time is 1-100 h, and the activation atmosphere is any one of N2, H2 and O2 or a mixture of several thereof.

4. The preparation method according to claim 2, wherein: The molecular sieve in step (2) is any one of S-1, Beta, and ZSM-5, or a mixture of several of them.

5. The preparation method according to claim 2, wherein: The auxiliary metal compound in step (3) is any one of diethyl zinc, copper acetylacetonate, trimethyl gallium, cerium acetylacetonate and cerium trimesic acid, or a mixture of several of them.

6. The preparation method according to claim 2, wherein: The main active metal Pt compound in step (4) is any one of methylcyclopentadienyltrimethylplatinum, acetylacetonate platinum, dinitrodiammineplatinum or a mixture thereof.

7. The preparation method according to claim 2, characterized in that: The inert gas in step (5) is any one of Ar, He and N2 or a mixture of several of them.

8. The preparation method according to claim 2, wherein: The deposition temperature in steps (3) and (4) is 100 to 1000°C, and the number of cycles is 10 to 1000 times.

9. The preparation method according to claim 2, wherein: The reduction temperature in step (5) is 100-900°C, and the reduction time is 1-100 h.

10. A Pt-based light alkane dehydrogenation catalyst with super stability at high temperature, obtained by the preparation method according to any one of claims 2 to 9.

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