Modified alumina-supported platinum-based alloy catalysts, methods of making and using the same

Abstract

The application belongs to the technical field of supported catalysts, and discloses a modified alumina-supported platinum-based alloy catalyst, a preparation method and application thereof, the catalyst is loaded with PtP alloy nanoparticles on a P-modified Al2O3 carrier, the micro composition of the PtP alloy nanoparticles is Pt1P3, the mass percentage of Pt in the catalyst is 0.1-0.5 wt%, and the mass percentage of P is 1.2-4.8 wt%. In the catalyst preparation process, the step-by-step impregnation and reduction method is adopted, the Al2O3 is sequentially impregnated in aqueous solutions of diammonium hydrogen phosphate and chloroplatinic acid, and after drying, calcination and high-temperature reduction, the PtP / P-Al2O3 catalyst is obtained. The catalyst is suitable for the reaction of propane dehydrogenation to propylene under a hydrogen atmosphere, the propane conversion rate is high, the propylene selectivity is higher than 90%, and after multiple cyclic regeneration, the catalyst can still restore the initial performance.

Description

Technical Field

[0001] This invention belongs to the field of supported catalyst technology. Specifically, it relates to a platinum-based alloy catalyst supported on modified alumina (Al2O3) and its preparation method, as well as its application in the dehydrogenation of low-carbon alkanes to olefins. Background Technology

[0002] Low-carbon olefins (such as ethylene, propylene, butene, and butadiene) are important basic raw materials for the chemical industry, especially propylene, whose demand has been increasing in recent years. Propylene is a fundamental raw material for the production of industrial products such as acrolein, acetone, polyacrylonitrile, propylene oxide, and epichlorohydrin. Traditionally, propylene production mainly comes from byproducts of the catalytic cracking and steam cracking processes of naphtha and light diesel oil. However, in recent years, with the rapid depletion of fossil fuels, propylene produced using traditional methods can no longer meet the growing global demand. With the development of hydraulic fracturing technology, shale gas has been extracted in large quantities, and the production of other low-carbon alkanes, such as ethane and propane, has increased significantly, except for methane. Compared to naphtha, ethane is cheaper, and ethylene production processes have begun to shift from naphtha cracking to ethane steam cracking, in which the yield of propylene as a byproduct is extremely low.

[0003] Direct propane dehydrogenation to propylene (C3H8=C3H6 + H2, PDH) offers high economic efficiency in carbon resource utilization and is a key technology for achieving the production of lighter olefins, aligning with national strategic needs. With the rapid development of propane dehydrogenation, older processes have been continuously improved, and new processes have emerged, leading to extensive development and updates in dehydrogenation technologies and catalysts. In recent years, processes such as Catofin, Oleflex, FBD-4, PDH, STAR, FCDh, ADHO, and K-PROTM have all been commercialized, with Catofin and Oleflex being the most widely used in industrial production.

[0004] Pt-based catalysts have demonstrated excellent CH bond activation capabilities in propane dehydrogenation, showcasing their value in the industrial production of propylene. The active component of Pt-based catalysts is typically metallic Pt clusters or nanoparticles. Larger Pt particles are more prone to side reactions such as cracking and carbon deposition during propane dehydrogenation. Furthermore, propane dehydrogenation is a strongly endothermic reaction, requiring high temperatures. Considering that Pt's Taman temperature is only 750°C and PtO2's melting point is only 450°C, severe sintering of Pt particles occurs during dehydrogenation and regeneration.

[0005] Alloying Pt with transition metals can enhance catalyst activity while effectively improving catalyst stability. In industrial PtSn / Al2O3 catalysts, tin (Sn) functions as both a geometric promoter and an electronic promoter. On one hand, Sn and Pt form PtSn alloy nanoparticles, diluting Pt atom clusters on the alloy surface by incorporating inert Sn atoms, thus disrupting continuous Pt sites that lead to coking. On the other hand, metallic Sn atoms donate electrons to neighboring Pt atoms, promoting propylene desorption, preventing deep dehydrogenation of propylene, and inhibiting carbon deposition. Simultaneously, unreduced SnO... x Sn promoters facilitate the migration of carbon deposit precursors from PtSn sites toward the support, mitigating catalyst deactivation caused by carbon deposition. Despite these beneficial effects, coking remains a persistent problem, and the traditional PtSn / Al2O3 system will gradually deactivate, requiring frequent and costly regeneration cycles to restore catalytic performance.

[0006] Introducing a second metal (Sn, Zn, Ga, Cu, etc.) to form an alloy is a mainstream modification strategy. However, the alloy itself is dynamically changing rather than statically stable under reaction conditions. Studies have confirmed that PtZn alloys undergo a dynamic transformation from large-particle fcc-Pt to highly dispersed, small-sized PtZn alloy clusters during reaction or reduction pretreatment. While this in-situ evolution can sometimes improve performance, it also means that the true structure of the catalyst's active center cannot be predetermined, increasing the difficulty of precise design. Non-noble metal additives (such as Zn and Cu) are prone to strong interactions with the support or oxidation separation under high-temperature oxidative regeneration atmospheres, disrupting the original alloy coordination environment and leading to weakened Pt-Cu or Pt-Zn interactions and degraded alloy performance. In contrast, transition metal phosphides have the advantage of high thermal stability, suggesting they may be potential catalysts for high-temperature reactions, such as propane dehydrogenation. Summary of the Invention

[0007] This invention aims to solve the technical problems of sintering and carbon deposition in existing Pt-Me bimetallic alloy catalysts (such as common alloy catalysts like PtCu, PtZn, and PtSn), and provides a modified alumina-supported platinum-based alloy catalyst and its preparation method, as well as its application in propane dehydrogenation reaction. This catalyst has the advantages of high activity, slow deactivation rate, and good stability in dehydrogenation-regeneration cycle, and has high industrial application value.

[0008] To achieve the above-mentioned objectives, the present invention is implemented through the following technical solution:

[0009] According to one aspect of the present invention, a modified alumina-supported platinum-based alloy catalyst is provided, comprising a P-modified Al2O3 support, wherein the P-modified Al2O3 support is modified with P on the surface of the Al2O3 support; PtP alloy nanoparticles are loaded on the P-modified Al2O3 support, the microstructure of the PtP alloy nanoparticles being Pt1P3; and based on the mass of the P-modified Al2O3 support, the mass percentage content of P is 0.1-0.5 wt%, and the mass percentage content of P is 1.2-4.8 wt%.

[0010] Preferably, based on the mass of the P-modified Al2O3 support, the mass percentage of Pt is 0.1 wt% and the mass percentage of P is 2.4 wt%.

[0011] According to another aspect of the present invention, a method for preparing a modified alumina-supported platinum-based alloy catalyst is provided, comprising:

[0012] (1) Dissolve H2PtCl6 and (NH4)2HPO4 in deionized water to obtain the corresponding precursor solutions;

[0013] (2) Impregnate Al2O3 in the (NH4)2HPO4 solution obtained in step (1) according to the proportion, sonicate until the mixture is uniform, dry, and then calcine the obtained solid at 500-700℃ for 3-8 h to obtain P-Al2O3 support;

[0014] (3) The P-Al2O3 support obtained in step (2) is impregnated in the H2PtCl6 solution obtained in step (1) in a certain proportion, ultrasonicated until uniformly mixed and dried, and then the obtained solid is reduced at 500-700℃ for 2-5 h to obtain a modified alumina supported platinum-based alloy catalyst.

[0015] Furthermore, the drying in steps (2) and (3) involves first drying naturally at room temperature, and then drying completely at 80-120°C.

[0016] Preferably, the roasting temperature in step (2) is 600℃ and the roasting time is 6 h.

[0017] Preferably, the reduction temperature in step (3) is 600℃ and the reduction time is 3 h.

[0018] According to another aspect of the present invention, the application of the above-described modified alumina-supported platinum-based alloy catalyst in the selective production of olefins from the direct dehydrogenation of low-carbon alkanes is provided.

[0019] Furthermore, it can be used for the selective production of propylene from the direct dehydrogenation of propane.

[0020] Preferably, the method for the selective production of propylene from direct dehydrogenation of propane comprises:

[0021] (1) The modified alumina-supported platinum-based alloy catalyst is pressed into tablets and sieved into granular catalyst with a mesh size of 20-60 mesh.

[0022] (2) The obtained granular catalyst is loaded into a fixed bed reactor, and 10 vol% hydrogen-nitrogen mixture is introduced. The temperature is raised to 500-700℃ for pre-reduction treatment and maintained for 1-3 h. Then the temperature is lowered to the reaction temperature of 500-600℃.

[0023] (3) A propane-hydrogen mixture is introduced to carry out the dehydrogenation reaction, wherein the molar ratio of hydrogen to propane is 0-2:1, and the space velocity of propane is 1-10 h⁻¹. -1 .

[0024] The beneficial effects of this invention are:

[0025] The modified alumina-supported platinum-based alloy catalyst of this invention forms Pt1P3 alloy nanoparticles through the reaction of post-supported Pt with P enriched on the surface of the P-Al2O3 support in a reducing atmosphere. This catalyst exhibits excellent propane dehydrogenation performance, and its performance remains stable after multiple dehydrogenation-regeneration cycles. Notably, due to the catalyst's enhanced anti-sintering ability, the Pt1P3 alloy nanoparticle structure in the catalyst remains stable after reaction and regeneration.

[0026] The modified alumina-supported platinum-based alloy catalyst of the present invention has a simple preparation process, readily available raw materials, high reproducibility, and certain industrial significance.

[0027] The modified alumina-supported platinum-based alloy catalyst of the present invention is suitable for propane dehydrogenation reaction under a hydrogen atmosphere. It has high dehydrogenation activity at high temperature, propylene selectivity can reach more than 90%, and it has good dehydrogenation-regeneration stability. Attached Figure Description

[0028] Figure 1 The transmission electron microscopy (TEM) results are for the modified alumina-supported platinum-based alloy catalyst prepared in Example 1.

[0029] Figure 2 The extended edge X-ray absorption fine structure (EXAFS) results are shown for the modified alumina-supported platinum-based alloy catalyst prepared in Example 1.

[0030] Figure 3 The graph shows the dehydrogenation-regeneration performance test (propane conversion and propylene selectivity) of the modified alumina-supported platinum-based alloy catalyst prepared in Example 1. Detailed Implementation

[0031] The present invention will be further described in detail below through specific embodiments. These embodiments will enable those skilled in the art to have a more comprehensive understanding of the present invention, but will not limit the present invention in any way.

[0032] Example 1:

[0033] (1) Dissolve 0.0021 parts by mass of H2PtCl6 and 0.1022 parts by mass of (NH4)2HPO4 in 2 mL of deionized water to form a clear and transparent solution.

[0034] (2) 1.0000 parts by mass of Al2O3 were impregnated in the (NH4)2HPO4 solution obtained in step (1), sonicated for 0.5 h, and naturally dried at room temperature. Then, the solid was completely dried at 100 °C and then calcined at 600 °C for 6 h to obtain the P-Al2O3 support.

[0035] (3) The solid powder obtained by the above treatment is immersed in the H2PtCl6 solution obtained in step (1), sonicated for 0.5 h, naturally dried at room temperature, and then completely dried at 80°C. The obtained solid is then reduced at 600°C for 3 h to obtain a modified alumina supported platinum-based alloy catalyst.

[0036] Based on the mass of the P-Al2O3 support, the catalyst contains 0.1 wt% Pt and 2.4 wt% P.

[0037] (4) The prepared PtP / P-Al2O3 catalyst is pressed into 20-60 mesh granular catalyst;

[0038] (5) The tableted PtP / P-Al2O3 granular catalyst was loaded into a fixed-bed reactor, and a 10 vol% hydrogen-nitrogen mixture was introduced. The temperature was raised to the pretreatment temperature of 600℃ and maintained for 1 h. Then the atmosphere was switched to the reaction gas, in which the molar ratio of hydrogen to propane was 1:1 and the propane mass hourly space velocity was 10 h⁻¹. -1 .

[0039] like Figure 1 As shown, the modified alumina-supported platinum-based alloy catalyst obtained in Example 1 was characterized by TEM, revealing that the PtP nanoparticles had a particle size of approximately 1 nanometer. Figure 2 As shown, its microstructure was determined to be Pt1P3. The reaction products were analyzed online using gas chromatography. The relationship between propane conversion and propylene selectivity and time is shown in the figure. Figure 3 As shown, the initial conversion rate of propane reached 50%, decreased to 40% after 4 hours, and the deactivation rate was 0.101 h. -1The propylene selectivity remained at a high level (>90%), and the catalyst could regain its initial activity after multiple dehydrogenation-regeneration processes.

[0040] Example 2:

[0041] The preparation and reaction were carried out using the method of Example 1, the only difference being that the mass of (NH4)2HPO4 in step (1) was 0.0256 parts by mass; and the mass percentage of P in the resulting catalyst was 0.6 wt% based on the mass of the P-Al2O3 support.

[0042] Example 3:

[0043] The preparation and reaction were carried out using the method of Example 1, the only difference being that the mass of (NH4)2HPO4 in step (1) was 0.0511 parts by mass; and the mass percentage of P in the resulting catalyst was 1.2 wt% based on the mass of the P-Al2O3 support.

[0044] Example 4:

[0045] The preparation and reaction were carried out using the method of Example 1, the only difference being that the mass of (NH4)2HPO4 in step (1) was 0.0767 parts by mass; and the mass percentage of P in the resulting catalyst was 1.8 wt% based on the mass of the P-Al2O3 support.

[0046] Example 5:

[0047] The preparation and reaction were carried out using the method of Example 1, the only difference being that the mass of (NH4)2HPO4 in step (1) was 0.2045 parts by mass; and the mass percentage of P in the resulting catalyst was 4.8 wt% based on the mass of the P-Al2O3 support.

[0048] Example 6:

[0049] The preparation and reaction were carried out using the method of Example 1, the only difference being that the mass of H2PtCl6 in step (1) was 0.001 parts by mass; and the mass percentage of Pt in the resulting catalyst was 0.05 wt% based on the mass of the P-Al2O3 support.

[0050] Example 7:

[0051] The preparation and reaction were carried out using the method of Example 1, the only difference being that the mass of H2PtCl6 in step (1) was 0.0063 parts by mass; and the mass percentage of Pt in the resulting catalyst was 0.3 wt% based on the mass of the P-Al2O3 support.

[0052] Example 8:

[0053] The preparation and reaction were carried out using the method of Example 1, the only difference being that the mass of H2PtCl6 in step (1) was 0.0105 parts by mass; and the mass percentage of Pt in the resulting catalyst was 0.5 wt% based on the mass of the P-Al2O3 support.

[0054] Example 9:

[0055] The preparation and reaction were carried out using the method of Example 1, the only difference being that the calcination temperature in step (2) was 400°C.

[0056] Example 10:

[0057] The preparation and reaction were carried out using the method of Example 1, the only difference being that the calcination temperature in step (2) was 500°C.

[0058] Example 11:

[0059] The preparation and reaction were carried out using the method of Example 1, the only difference being that the calcination temperature in step (2) was 700°C.

[0060] Example 12:

[0061] The preparation and reaction were carried out using the method of Example 1, the only difference being that the calcination temperature in step (2) was 900°C.

[0062] Example 13:

[0063] The preparation and reaction were carried out using the method of Example 1, except that the calcination time in step (2) was 1 h.

[0064] Example 14:

[0065] The preparation and reaction were carried out using the method of Example 1, the only difference being that the calcination time in step (2) was 3 h.

[0066] Example 15:

[0067] The preparation and reaction were carried out using the method of Example 1, the only difference being that the calcination time in step (2) was 8 h.

[0068] Example 16:

[0069] The preparation and reaction were carried out using the method of Example 1, the only difference being that the reduction temperature in step (3) was 500°C.

[0070] Example 17:

[0071] The preparation and reaction were carried out using the method of Example 1, the only difference being that the reduction temperature in step (3) was 700°C.

[0072] Example 18:

[0073] The preparation and reaction were carried out using the method of Example 1, the only difference being that the reduction time in step (3) was 1 h.

[0074] Example 19:

[0075] The preparation and reaction were carried out using the method of Example 1, the only difference being that the reduction time in step (3) was 3 h.

[0076] Example 20:

[0077] The preparation and reaction were carried out using the method of Example 1, the only difference being that the reduction time in step (3) was 5 h.

[0078] The results of the above embodiments are all compared using activity data at the beginning and end of the reaction. The test conditions and methods are the same as in Example 1 to examine the effect of different parameters on the catalyst reaction performance.

[0079] (a) The effect of the mass percentage of P (based on the mass of the P-Al2O3 support in the catalyst) on the reactivity of the PtP / P-Al2O3 catalyst is shown in Table 1. The reaction conditions are the same as in Examples 1, 2, 3, 4, and 5.

[0080] Table 1. Effect of different P mass percentages on propane dehydrogenation activity

[0081] 0.6 39 / 23 82 / 84 0.190 1.2 43 / 27 88 / 89 0.179 1.8 45 / 30 88 / 90 0.162 2.4 50 / 40 90 / 92 0.101 4.8 50 / 31 88 / 89 0.200

[0082] As shown in Table 1, when the mass fraction of P is 0.6 wt%, the propane conversion and propylene selectivity of the PtP alloy catalyst need to be further improved. In contrast, when the mass fraction of P is 1.2-4.8 wt%, the catalyst achieves both high activity and stability. Among these, the performance is optimal when the P loading is 2.4 wt%, with a propane conversion of approximately 50% and a selectivity greater than 90% in the initial stage of the reaction, and a deactivation rate of 0.101.

[0083] (ii) The effect of the mass percentage of Pt (based on the mass of the P-Al2O3 support in the catalyst) on the reactivity of the PtP / P-Al2O3 catalyst is shown in Table 2. The reaction conditions are the same as in Examples 1, 6, 7, and 8.

[0084] Table 2. Effect of different Pt mass percentages on catalytic activity

[0085] 0.05 28 / 21 92 / 93 0.095 0.1 50 / 40 90 / 92 0.101 0.3 53 / 37 91 / 92 0.133 0.5 56 / 40 89 / 91 0.162

[0086] As shown in Table 2, when the Pt mass fraction is 0.05 wt%, the catalyst activity is too low to meet the requirements. When the Pt mass fraction is increased to 0.1-0.5 wt%, the catalyst activity is significantly improved. When the Pt mass fraction is moderate (0.1 wt%), the catalyst can achieve both good activity and stability.

[0087] (III) The effect of calcination temperature of P-Al2O3 support on the catalytic activity of PtP / P-Al2O3 catalyst is shown in Table 3. The reaction conditions are the same as in Examples 1, 9, 10, 11, and 12.

[0088] Table 3. Effect of P-Al2O3 support calcination temperature on catalytic activity

[0089] 400 33 / 21 90 / 91 0.154 500 44 / 34 90 / 92 0.106 600 50 / 40 90 / 92 0.101 700 49 / 38 90 / 92 0.112 900 14 / 11 93 / 94 0.069

[0090] As shown in Table 3, when the calcination temperature of the P-Al2O3 support is too low (400℃), the interaction strength between P and Al2O3 is low, resulting in poor catalyst performance. Conversely, when the calcination temperature of the P-Al2O3 support is too high (900℃), P-Al2O3 is prone to sintering and P volatilization, leading to excessively low catalyst performance. In contrast, when the calcination temperature of the P-Al2O3 support is between 500-700℃, the catalyst activity is significantly improved.

[0091] (iv) The effect of P-Al2O3 support calcination time on the catalytic activity of PtP / P-Al2O3 catalyst is shown in Table 4. The reaction conditions are the same as in Examples 1, 13, 14, and 15.

[0092] Table 4. Effect of P-Al2O3 support calcination temperature on catalytic activity

[0093] 1 28 / 17 85 / 88 0.160 3 42 / 32 89 / 91 0.108 6 50 / 40 90 / 92 0.101 8 48 / 36 91 / 92 0.124

[0094] As shown in Table 4, when the calcination time of the P-Al2O3 support is insufficient (1 h), the interaction strength between P and Al2O3 is low, resulting in poor catalyst performance. However, when the calcination time of the P-Al2O3 support is extended to 3-8 h, the catalyst activity and selectivity are significantly improved, with the catalyst exhibiting the best performance at a calcination time of 6 h.

[0095] (v) The effect of reduction temperature on the catalytic activity of PtP / P-Al2O3 catalyst is shown in Table 5. The reaction conditions are the same as in Examples 1, 16, and 17.

[0096] Table 5. Effect of reduction temperature on catalytic activity

[0097] 500 41 / 27 89 / 90 0.158 600 50 / 40 90 / 92 0.101 700 49 / 38 90 / 92 0.112

[0098] The results in the table show that, within the selected reduction temperature range, the initial conversion of the catalysts obtained were all above 40%, and the propylene selectivity was all above 90%.

[0099] (vi) Effect of reduction time on the catalytic activity of PtP / P-Al2O3 catalyst, see Table 6. The reaction conditions are the same as in Examples 1, 18, 19, and 20.

[0100] Table 6. Effect of reduction time on catalytic activity

[0101] 1 33 / 17 90 / 91 0.219 2 45 / 34 90 / 91 0.116 3 50 / 40 90 / 92 0.101 5 51 / 40 91 / 92 0.111

[0102] As shown in Table 6, when the reduction time increases from 1 h to 2 h, the activity and stability of the catalyst steadily improve, while further increasing the reduction time to 5 h does not significantly change the activity and stability. Therefore, the optimal reduction time is 2-5 h.

[0103] Although the preferred embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many specific modifications under the guidance of the present invention without departing from the spirit and scope of the claims, and these modifications all fall within the scope of protection of the present invention.

Claims

1. A modified alumina-supported platinum-based alloy catalyst, characterized in that, The invention includes a P-modified Al2O3 support, wherein the P-modified Al2O3 support is an Al2O3 support with P modified on its surface; PtP alloy nanoparticles are loaded on the P-modified Al2O3 support, and the microstructure of the PtP alloy nanoparticles is Pt1P3; based on the mass of the P-modified Al2O3 support, the mass percentage of P is 0.1-0.5 wt%, and the mass percentage of P is 1.2-4.8 wt%.

2. The modified alumina-supported platinum-based alloy catalyst according to claim 1, characterized in that, Based on the mass of the P-modified Al2O3 support, the mass percentage of Pt was 0.1 wt% and the mass percentage of P was 2.4 wt%.

3. A method for preparing a platinum-based alloy catalyst supported on modified alumina as described in any one of claims 1-2, characterized in that, include: (1) Dissolve H2PtCl6 and (NH4)2HPO4 in deionized water to obtain the corresponding precursor solutions; (2) Impregnate Al2O3 in the (NH4)2HPO4 solution obtained in step (1) according to the proportion, sonicate until the mixture is uniform, dry, and then calcine the obtained solid at 500-700℃ for 3-8 h to obtain P-Al2O3 support; (3) The P-Al2O3 support obtained in step (2) is impregnated in the H2PtCl6 solution obtained in step (1) in a certain proportion, ultrasonicated until uniformly mixed and dried, and then the obtained solid is reduced at 500-700℃ for 2-5 h to obtain a modified alumina supported platinum-based alloy catalyst.

4. The method for preparing the modified alumina-supported platinum-based alloy catalyst according to claim 3, characterized in that, The drying in steps (2) and (3) involves first drying naturally at room temperature, and then drying completely at 80-120℃.

5. The method for preparing the modified alumina-supported platinum-based alloy catalyst according to claim 3, characterized in that, The roasting temperature in step (2) is 600℃ and the roasting time is 6 h.

6. The method for preparing the modified alumina-supported platinum-based alloy catalyst according to claim 3, characterized in that, The reduction temperature in step (3) is 600℃ and the reduction time is 3 h.

7. The application of a platinum-based alloy catalyst supported on alumina as described in any one of claims 1-2 in the selective production of olefins from direct dehydrogenation of low-carbon alkanes.

8. The application of the modified alumina-supported platinum-based alloy catalyst according to claim 7 in the selective direct dehydrogenation of low-carbon alkanes to olefins, characterized in that, Used for the selective production of propylene from direct dehydrogenation of propane.

9. The application of the modified alumina-supported platinum-based alloy catalyst according to claim 8 in the selective direct dehydrogenation of low-carbon alkanes to olefins, characterized in that, Used for the selective production of propylene from direct dehydrogenation of propane, including: (1) The modified alumina-supported platinum-based alloy catalyst is pressed into tablets and sieved into granular catalyst with a mesh size of 20-60 mesh. (2) The obtained granular catalyst is loaded into a fixed bed reactor, and 10 vol% hydrogen-nitrogen mixture is introduced. The temperature is raised to 500-700℃ for pre-reduction treatment and maintained for 1-3 h. Then the temperature is lowered to the reaction temperature of 500-600℃. (3) A propane-hydrogen mixture is introduced to carry out the dehydrogenation reaction, wherein the molar ratio of hydrogen to propane is 0-2:1, and the space velocity of propane is 1-10 h⁻¹. -1 .

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