A low-temperature high-efficiency anti-poisoning palladium-based catalyst for dehydrogenation and a preparation method and application thereof

Abstract

The application discloses a low-temperature high-efficiency anti-poisoning dehydrogenation palladium-based catalyst and a preparation method and application thereof, and belongs to the technical field of palladium-based catalysts and natural gas helium extraction. The catalyst takes ultrasonic modification gamma-Al2O3 nitric acid as a carrier, loads Pd and a catalyst promoter, and forms Pd-M nanoclusters with a size of 3-5 nm through vacuum isometric impregnation and gradient activation processes. The conversion rate of the catalyst reaches 99.8% at 240 DEG C, the catalyst is resistant to H2S>1ppm and CO>50ppm, the activity retention rate of the catalyst is greater than 95% after continuous operation for 100 hours under high hydrogen partial pressure, and the helium recovery rate is greater than 99.3%. The application solves the problems of poor low-temperature activity, easy poisoning and insufficient stability of traditional palladium-based catalysts, and has remarkable industrial application value.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of palladium-based catalysts and helium extraction from natural gas, and particularly relates to a low-temperature, high-efficiency, and anti-poisoning palladium-based catalyst for removing hydrogen from crude helium in a helium extraction process from natural gas, a preparation method of the catalyst, and an application of the catalyst in a catalytic dehydrogenation reaction of hydrogen-containing gas. BACKGROUND

[0002] Helium is an important strategic resource and is widely used in the fields of low-temperature superconducting, aerospace, semiconductor, and medical treatment. China is relatively short of helium resources and mainly relies on imports, so it is crucial to efficiently develop the associated helium in natural gas. In the process of conventional helium extraction from natural gas, the concentration of hydrogen in crude helium is significantly increased.

[0003] In the process of conventional helium extraction from natural gas (such as low-temperature condensation, membrane separation, and pressure swing adsorption), the concentration of hydrogen in crude helium is significantly increased (up to 20%-50% vol). High-concentration hydrogen brings three major problems: (1) safety risk: the explosion limit of hydrogen is wide (4%-75% vol), and the increase in the concentration of hydrogen in crude helium significantly increases the risk of combustion and explosion in the subsequent processing, storage, and transportation processes; (2) difficulty in subsequent refining: high-concentration hydrogen affects the efficiency of subsequent low-temperature refining and other steps and the purity of the final helium, increasing the difficulty of separation and energy consumption; (3) challenge in impurity separation: hydrogen and helium have similar physical and chemical properties (such as molecular size and boiling point), making it difficult to separate them.

[0004] Currently, traditional dehydrogenation methods (such as combustion and cryogenic separation) generally have high energy consumption, complex process flow, and the potential to reduce the recovery rate of helium. Although conventional palladium catalysts have good selectivity for hydrogen-oxygen reactions, they also have many shortcomings, such as (1) poor low-temperature activity: a temperature of more than 300°C is required to achieve a hydrogen conversion rate of >90%, which increases energy consumption and the risk of equipment corrosion; (2) easy poisoning: sensitive to trace amounts of sulfides (such as H2S) and CO in the raw gas, which permanently occupy active sites after adsorption, leading to permanent deactivation of the catalyst; (3) poor stability: under high hydrogen partial pressure (>20% vol), palladium particles are prone to sintering and growing (particle size increases from 5 nm to more than 20 nm), reducing the number of active sites and shortening the service life; (4) poor adaptability to high hydrogen partial pressure: unable to effectively process crude helium with a hydrogen concentration of more than 20%, which easily leads to "hydrogen overflow" and causes damage to the carrier structure.

[0005] Therefore, developing a low-temperature, high-efficiency, and anti-poisoning palladium-based catalyst that is suitable for high hydrogen partial pressure is a key breakthrough point for helium extraction from natural gas.

[0006] A Chinese patent application published as CN111036231A discloses a water-resistant palladium-based catalyst for catalytic combustion of benzene, a preparation method and use thereof. The catalyst comprises an alumina carrier and an active component and a dopant supported on the carrier. The active component comprises Pd particles, and the dopant comprises sodium carbonate. The catalyst is prepared by (1) mixing alumina, a palladium precursor and a sodium source in a solvent, and then removing the solvent to obtain a uniform mixture; (2) calcining the uniform mixture to obtain a calcined product in which palladium mainly exists in the form of palladium oxide; and (3) reducing the calcined product to reduce the palladium oxide into elemental palladium, thereby obtaining the water-resistant palladium-based catalyst. Although the catalyst of the patent has the effect of catalytic degradation of benzene, a highly toxic volatile organic compound, the preparation process is relatively complicated, and the catalytic efficiency at low temperature is low, and thus further research and improvement are needed. SUMMARY

[0007] The technical problem to be solved by the present application is how to solve the problems of poor low-temperature activity, easy poisoning and insufficient stability of existing palladium-based catalysts, and to provide a palladium-based catalyst for safe and efficient dehydrogenation of crude helium gas in the process of extracting helium from natural gas.

[0008] The present application solves the above technical problems by the following technical means:

[0009] The present application provides a preparation method of a palladium-based catalyst for dehydrogenation, comprising the following steps:

[0010] (1) carrier pretreatment:

[0011] The γ-Al2O3 is placed in a nitric acid solution, ultrasonically treated, dried, and calcined to obtain a modified γ-Al2O3 carrier;

[0012] (2) gradient calcination after impregnation:

[0013] The impregnation solution is loaded onto the modified γ-Al2O3 carrier by vacuum isometric impregnation, dried, and gradient calcined;

[0014] The impregnation solution is composed of chloropalladic acid, a co-catalyst and water; the co-catalyst refers to a nitrate salt containing one or more of Pt, Au, Ag, Ni, Cu, Ce, La, Co and other transition metals or rare earth metals;

[0015] (3) reduction and passivation:

[0016] The product of step (2) is reduced under a H2 / N2 mixed gas atmosphere by gradient temperature rising, cooled, and passivated to obtain the palladium-based catalyst for dehydrogenation.

[0017] Preferably, in step (1), the concentration of the nitric acid solution is 5-15 vol%.

[0018] Preferably, in step (1), the ultrasonic treatment time is 0.5-2 hours.

[0019] Preferably, in step (1), the specific surface area of the modified γ-Al2O3 carrier is 200-350 m² / g, and the pore volume is 0.4-0.8 cm³ / g.

[0020] Preferably, in step (1), the calcination conditions are 400-600℃ for 1-6 hours.

[0021] Preferably, in step (2), the volume ratio of the impregnation solution to the modified γ-Al2O3 carrier is 1:1.

[0022] Preferably, in step (2), the promoter M is one or more of cerium nitrate and platinum nitrate.

[0023] Preferably, in step (2), the mass ratio of the chloropalladic acid to the promoter is (1.5-10):(6-30).

[0024] Preferably, in step (2), the drying method is to heat the sample in air at a rate of 1-5℃ / min to 80-120℃ for 0.5-2 hours; further preferably, at a rate of 3℃ / min to 110℃ for 1 hour.

[0025] Preferably, in step (2), the gradient calcination method is to heat the sample in air at a rate of 1-5℃ / min to 250-450℃ for 1-6 hours; further preferably, at a rate of 3℃ / min to 350℃ for 3 hours.

[0026] Preferably, in step (3), the volume ratio of H2 to N2 is 1:(1-19).

[0027] Preferably, in step (3), the gradient heating refers to heating at a rate of 1-5℃ / min to 250℃.

[0028] Preferably, in step (3), the reduction time is 1-6 hours.

[0029] Preferably, in step (3), the Pd-M nanocluster formed after reduction has a size of 3-5 nm.

[0030] Preferably, M in the Pd-M nanocluster refers to one or more of Pt, Au, Ag, Ni, Cu, Ce, La, Co, and other transition metals or rare earth metals.

[0031] Preferably, in step (3), the passivation treatment method is to pass 0.8 vol% O2 in nitrogen for 2 hours.

[0032] The present application also provides a palladium-based catalyst for dehydrogenation prepared by the above method.

[0033] The application further provides application of the palladium-based catalyst for dehydrogenation prepared by the preparation method in a catalytic dehydrogenation reaction of a hydrogen-containing gas.

[0034] Preferably, the hydrogen-containing gas comprises natural gas crude gas for helium extraction, fuel cell tail gas or chemical vent gas.

[0035] The application has the following beneficial effects:

[0036] 1. The catalyst has a support of ultrasonic modified gamma-Al2O3 (specific surface area 200-350 m² / g, pore volume 0.4-0.8 cm³ / g) by nitric acid, and is loaded with Pd (0.5-3.0 wt%) and a promoter (Ce, Pt, etc., 1.5-8.0 wt%). A Pd-M nanocluster with a particle size of 3-5 nm is formed by vacuum isometric impregnation and gradient activation. The catalyst solves the problems of poor low-temperature activity, easy poisoning and insufficient stability of traditional palladium-based catalysts, and has significant industrial application value.

[0037] 2. In the pretreatment of the support, the pore structure of the support is increased by the corrosion of nitric acid. Meanwhile, the thermal stability of the support is enhanced by high-temperature calcination to inhibit phase transition (such as conversion to alpha-Al2O3) at high temperatures. Vacuum isometric impregnation and gradient activation are adopted. Vacuum impregnation ensures uniform penetration of the solution into the pores of the support, avoiding Pd particle aggregation. Gradient activation (drying, calcination and reduction in sequence) controls the growth of palladium particles (particle size 3-5 nm), forms a Pd-M nanocluster with high specific surface area, and provides active sites (>150 m² / g).

[0038] 3. Low-temperature high activity: the conversion rate is 99.8% at 240°C, which is about 37.5% lower than that of traditional catalysts (300-400°C), and the energy consumption is reduced by more than 40%.

[0039] 4. Strong resistance to poisoning: the synergistic effect of the promoter makes the catalyst resistant to H2S>1ppm (the concentration of H2S in the raw gas is usually 0.5-2.0 ppm) and CO>50ppm (the concentration of CO in the raw gas is usually 10-30 ppm).

[0040] 5. High stability: the Pd-M nanocluster with a particle size of 3-5 nm is not easy to sinter (the particle size is still <6 nm after calcination at 500°C), and the activity retention rate is >95% after continuous operation for 100 hours under high hydrogen partial pressure (50% vol) (the activity retention rate of traditional catalysts is <60%).

[0041] 6. High helium recovery rate: low-temperature operation avoids the reaction of helium with other components, and the helium recovery rate is >99.3% (the helium recovery rate of traditional catalysts is <90%).

[0042] Of course, practicing any of the products or methods of the present application does not necessarily require that all of the advantages discussed above be achieved. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 TEM image of Pd-Ce / γ-Al2O3 prepared for Example 1;

[0044] Figure 2 Hydrogen conversion plot of Pd-Ce / γ-Al2O3 prepared for Example 1 at different temperatures;

[0045] Figure 3 Poisoning (H2S) resistance analysis plot of Pd-Ce / γ-Al2O3 prepared for Example 1;

[0046] Figure 4 Poisoning (CO) resistance analysis plot of Pd-Ce / γ-Al2O3 prepared for Example 1;

[0047] Figure 5 Hydrogen conversion plot of catalysts prepared for Example 1, Comparative Examples 1-3 at different temperatures;

[0048] Figure 6 Poisoning (CO) resistance analysis plot of catalyst prepared for Comparative Example 1;

[0049] Figure 7 Poisoning (CO) resistance analysis plot of catalyst prepared for Comparative Example 2;

[0050] Figure 8 Poisoning (CO) resistance analysis plot of catalyst prepared for Comparative Example 3;

[0051] Figure 9 Poisoning (H2S) resistance analysis plot of catalyst prepared for Comparative Example 1;

[0052] Figure 10 Poisoning (H2S) resistance analysis plot of catalyst prepared for Comparative Example 2;

[0053] Figure 11 Poisoning (H2S) resistance analysis plot of catalyst prepared for Comparative Example 3. DETAILED DESCRIPTION

[0054] In order to make the objectives, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be clearly and completely described below in combination with specific examples. Obviously, the described examples are only a part of the examples of the present application, rather than all the examples. Based on the examples in the present application, all other examples obtained by those skilled in the art without creative effort shall fall into the protective scope of the present application. Unless otherwise defined, the professional terms used below are consistent with the meanings understood by those skilled in the art.

[0055] The test materials and reagents used in the following examples, unless otherwise specified, can be obtained commercially or prepared by known methods.

[0056] Unless otherwise specified, the technical or conditions not specified in the examples can be carried out according to the techniques or conditions described in the literature in the art or according to the product instructions. Unless otherwise specified, the quantitative tests in the following examples are set up with more than three repeated experiments, and the results are averaged.

[0057] Example 1 Preparation of catalyst

[0058] (1) Carrier pretreatment: Take commercial γ-Al2O3 powder, grind it in a ball mill and pass it through a 100-mesh sieve. Weigh 100 g of the sieved γ-Al2O3 and place it in a 10 vol% nitric acid solution. Ultrasonically treat it at 60°C for 1 hour. Filter and wash with deionized water until neutral. Dry it in an oven at 110°C for 12 hours. Place the dried carrier in a muffle furnace and heat it to 500°C at a rate of 2°C / min in an air atmosphere. Calcine it for 4 hours to obtain a modified γ-Al2O3 carrier (specific surface area 280 m² / g, pore volume 0.55 cm³ / g).

[0059] (2) Preparation of impregnation solution: Weigh 4.35 g of chloropalladic acid (H2PdCl4) and 9.8 g of cerium nitrate (Ce(NO3)3·6H2O). Dissolve them in deionized water to prepare a mixed impregnation solution with a total volume equal to the total pore volume of the carrier in step 1 (55 mL).

[0060] (3) Equal-volume impregnation: Place the modified γ-Al2O3 carrier in a vacuum impregnation device. Vacuumize it to 10 Pa and maintain for 30 minutes. While maintaining the vacuum state, slowly add the mixed impregnation solution prepared in step 2 to the carrier, ensuring that the solution is completely and uniformly absorbed by the carrier. After impregnation, let it stand at room temperature for 12 hours.

[0061] (4) Gradient calcination: drying: transfer the wet carrier to an oven and heat it to 110°C at a rate of 3°C / min in a flowing air atmosphere. Keep it at this temperature for 1 hour; calcination: continue to heat it to 350°C at a rate of 3°C / min in a flowing air atmosphere. Keep it at this temperature for 3 hours. Let it cool naturally to room temperature.

[0062] (5) Hydrogen reduction: The calcined sample was transferred to a tube furnace. H2 / N2 mixture (H2:N2 volume ratio = 1:9) was introduced, and the temperature was raised to 250°C at a rate of 3°C / min. The reduction was carried out at this temperature for 4 hours. After the reduction, the sample was cooled to below 50°C under N2 atmosphere. Pd-M nanoclusters of 3-5 nm were obtained.

[0063] (6) Passivation treatment: 0.8 vol% O2 was introduced into the reduction furnace, and the catalyst was treated for 2 hours to form a thin oxide layer on the surface of the catalyst, preventing severe oxidation or spontaneous combustion when exposed to air. After passivation, the catalyst was cooled to room temperature under N2 protection and sealed for storage. The obtained catalyst was labeled as Pd-Ce / γ-Al2O3. The TEM image is shown in Figure 2. Figure 1

[0064] Example 2:

[0065] The difference between this example and Example 1 is that in step (2), the impregnation solution is prepared by weighing 1.7 g of palladium chloride (H2PdCl4) and 6.4 g of cerium nitrate (Ce(NO3)3·6H2O), and the rest is the same as Example 1.

[0066] Example 3:

[0067] The difference between this example and Example 1 is that in step (2), the impregnation solution is prepared by weighing 9.5 g of palladium chloride (H2PdCl4) and 28 g of cerium nitrate (Ce(NO3)3·6H2O), and the rest is the same as Example 1.

[0068] Example 4:

[0069] The difference between this example and Example 1 is that in step (2), the impregnation solution is prepared by weighing 4.35 g of palladium chloride (H2PdCl4) and 8.3 g of platinum nitrate (Pt(NO3)4·4H2O), and the rest is the same as Example 1.

[0070] Example 5:

[0071] The difference between this example and Example 1 is that in step (1), the carrier modification is carried out by using a 5 vol% nitric acid solution, ultrasonic treatment at 60°C for 0.5 hours, and calcination at 400°C for 2 hours. The rest is the same as Example 1.

[0072] Example 6:

[0073] The difference between this example and Example 1 is that in step (1), the carrier modification is carried out by using a 15 vol% nitric acid solution, ultrasonic treatment at 60°C for 2 hours, and calcination at 600°C for 1 hour. The rest is the same as Example 1.

[0074] Example 7:

[0075] ​The difference between this example and Example 1 is that step (4) gradient calcination: drying: the wet carrier is transferred to the oven, and the temperature is raised to 110°C at 1°C / min in flowing air, and kept for 1 hour; calcination: continue to raise the temperature to 350°C at 1°C / min in flowing air, and keep for 1 hour. The rest is the same as Example 1.

[0076] Example 8:

[0077] The difference between this example and Example 1 is that step (4) gradient calcination: drying: the wet carrier is transferred to the oven, and the temperature is raised to 120°C at 5°C / min in flowing air, and kept for 2 hours; calcination: continue to raise the temperature to 450°C at 5°C / min in flowing air, and keep for 6 hours. The rest is the same as Example 1.

[0078] Example 9:

[0079] The difference between this example and Example 1 is that step (5) hydrogen reduction: the calcined sample is transferred to a tube furnace. H2 / N2 mixed gas (H2:N2 volume ratio = 1:19) is introduced, and the temperature is raised to 250°C at 1°C / min, and reduced for 1 hour at this temperature. After the reduction is completed, it is cooled to below 50°C under N2 atmosphere.

[0080] Example 10:

[0081] The difference between this example and Example 1 is that step (5) hydrogen reduction: the calcined sample is transferred to a tube furnace. H2 / N2 mixed gas (H2:N2 volume ratio = 1:10) is introduced, and the temperature is raised to 250°C at 3°C / min, and reduced for 3 hours at this temperature. After the reduction is completed, it is cooled to below 50°C under N2 atmosphere.

[0082] Example 11:

[0083] The difference between this example and Example 1 is that step (5) hydrogen reduction: the calcined sample is transferred to a tube furnace. H2 / N2 mixed gas (H2:N2 volume ratio = 1:1) is introduced, and the temperature is raised to 250°C at 5°C / min, and reduced for 6 hours at this temperature. After the reduction is completed, it is cooled to below 50°C under N2 atmosphere.

[0084] Example 12: Catalyst performance evaluation

[0085] (1) Hydrogen conversion performance test

[0086] Take 1 g of catalyst prepared in Example 1 and place it in a fixed bed reactor. Under the reaction conditions of GHSV = 4000 h -1, raw material gas is 2.0% H2+ 1.0% O2+ N2, and the activity test is carried out. From 180°C, the temperature is increased by 10°C as an interval to 340°C. Each temperature point is kept constant for at least 1 hour, and after the output signal is stable, the on-line GC sampling analysis is carried out. Hydrogen conversion rate (X H2 ) calculation formula:

[0087]

[0088] wherein, and are the hydrogen molar flow rate at the inlet and outlet of the reactor (calculated from the concentration and total flow rate analyzed by GC). The results show (as shown in Figure 2 ) that the conversion rate of the catalyst reaches 99.4% at 210°C, and the conversion rate reaches 99.8% at 240°C, and the catalytic performance is excellent.

[0089] (2) Anti-poisoning (H2S) performance test

[0090] 1 g of the catalyst prepared in Example 1 is taken and placed in a fixed bed reactor. The reaction condition is GHSV = 4000 h -1 , and the raw material gas is 2.0% H2+ 1.0% O2+ trace amount of H2S+ N2, and the activity test is carried out. The amount of H2S is 0.5, 1, 1.5, 2 ppm, and after the output signal is stable at 240°C for 10, 50, 100 hours, the on-line GC sampling analysis is carried out.

[0091] Activity retention rate ( ) calculation formula:

[0092]

[0093] wherein, Y1 is the hydrogen conversion rate after the reaction, and X H2 is the hydrogen conversion rate before the reaction. The results show (as shown in Figure 3 ) that even in the atmosphere of 2 ppm H2S, the activity retention rate after 100 hours of reaction still remains at 96.5%. It shows that it has high anti-S poisoning performance.

[0094] (3) Anti-poisoning (CO) performance test

[0095] The steps are the same as (2), and the poisoning stage is changed to introduce 10, 20, 30, 40, 50, 60, 70 ppm CO for 2 hours. The results show (as shown in Figure 4 ) that even in the atmosphere of 70 ppm CO, the activity retention rate after 100 hours of reaction still remains at 96.5%. It shows that it has high anti-CO poisoning performance.

[0096] Comparative Example 1:

[0097] The difference between this comparative example and Example 1 is that the impregnation solution in step (2) is prepared by dissolving 0.85 g of chloropalladic acid (H2PdCl4) in deionized water to a total volume equal to the total pore volume of the carrier in step 1 (55 mL) (i.e., the impregnation solution lacks a promoter).

[0098] The prepared catalyst has reduced resistance to H2S and CO.

[0099] Without the promoter Ce, the oxygen storage capacity of CeO2 is critical for low-temperature activity, and without CeO2, the reaction relies entirely on the dissociative adsorption of gaseous O2 on the Pd surface; CeO2 captures H2S by irreversibly forming Ce2(SO4)3, protecting the Pd active sites. Without Ce, H2S directly forms Pd4S with Pd, causing permanent deactivation.

[0100] The absence of La2O3 leads to collapse of the carrier: γ-Al2O3 transforms into low specific surface area α-Al2O3 (sintering) at >800°C. La2O3 inhibits the phase transition by forming a perovskite layer of LaAlO3; the sulfur resistance mechanism fails.

[0101] Comparative Example 2:

[0102] The difference between this comparative example and Example 1 is that step (4) is directly calcined at 500°C without gradient heating.

[0103] The prepared catalyst has Pd particles with a growth particle size >20 nm.

[0104] During the decomposition of the Pd precursor into active PdO / Pd 0 , it undergoes a low-temperature decomposition-high-temperature stabilization process. If the temperature is rapidly increased from low to high directly, the precursor will decompose violently in a very short time, generating a huge local overheating and vapor pressure, leading to Pd atom agglomeration; directly leading to: sharp reduction in the number of active centers (sintering, embedding); deterioration of the quality of active centers (loss of electronic promotion by the promoter); collapse of the carrier structure (pore destruction, failure of the stabilizing effect of the promoter).

[0105] Comparative Example 3:

[0106] The difference between this comparative example and Example 1 is that the γ-Al2O3 carrier in step (1) is not treated with nitric acid. The prepared catalyst has a smaller specific surface area and pore volume of γ-Al2O3.

[0107] The unmodified carrier lacks sufficient anchoring sites, resulting in uneven distribution of the co-catalyst and functional failure. Metal ions cannot form stable bonds with the carrier surface, and will migrate and agglomerate during calcination and reduction, failing to effectively play a co-catalytic role. The carrier is precisely controlled by nitric acid treatment to regulate the surface chemical properties (acid-base, anchoring sites) of the carrier, laying the foundation for high metal dispersion, anti-carbon deposition and co-catalyst synergy.

[0108] The hydrogen conversion rate comparison chart of the catalysts prepared in Comparative Examples 1-3 and the catalyst of Example 1 at different temperatures is shown in Figure 5

[0109] The anti-poisoning test data chart of Comparative Examples 1-3 is shown in Figures 6-11

[0110] The above examples are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions recorded in the foregoing examples can still be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.​​

Claims

1. A method for producing a palladium-based catalyst for dehydrogenation, characterized by, The preparation method comprises the following steps: (1) carrier pretreatment: placing γ-Al2O3 in a nitric acid solution, ultrasonic treatment, drying, and calcination to obtain a modified γ-Al2O3 carrier; the concentration of the nitric acid solution is 5-15 vol%, the ultrasonic treatment time is 0.5-2 hours, and the calcination conditions are 400-600 ℃ for 1-6 hours; (2) post-impregnation gradient calcination: loading an impregnation solution onto the modified γ-Al2O3 carrier by vacuum isometric impregnation, drying, and gradient calcination; the gradient calcination method is to heat the sample to 250-450 ℃ at a heating rate of 1-5 ℃ / min in air; the impregnation solution is composed of chloropalladic acid, a promoter, and water; the promoter refers to a nitrate salt containing one or more of Pt, Au, Ag, Ni, Cu, Ce, La, and Co; (3) reduction and passivation: gradient temperature reduction of the product of (2) in an H2 / N2 mixed gas atmosphere, cooling, and passivation treatment, and the product is obtained; the passivation treatment method is to pass 0.8 vol% O2 in nitrogen for 2 hours.

2. The production method according to claim 1, characterized by, In step (1), the concentration of the nitric acid solution is 10 vol%, the ultrasonic treatment time is 1 hour, and the calcination conditions are 500 ℃ for 4 hours.

3. The preparation method according to claim 1, characterized in that, In step (2), the volume ratio of the impregnation solution to the modified γ-Al2O3 carrier is 1:

1.

4. The method of claim 1, wherein, In step (2), the mass ratio of chloropalladic acid to promoter is (1.5-10):(6-30).

5. The preparation method according to claim 1, characterized in that, In step (2), the drying method is to heat the sample to 80-120 ℃ at a heating rate of 1-5 ℃ / min and keep the temperature for 0.5-2 hours in air.

6. The method of claim 1, wherein, In step (2), the gradient calcination method is to heat the sample to 350 ℃ at a heating rate of 3 ℃ / min in air.

7. The preparation method according to claim 1, characterized in that, In step (3), the volume ratio of H2 to N2 is 1:(1-19), the gradient heating refers to heating at a rate of 1-5 ℃ / min to 250 ℃, and the reduction time is 1-6 hours.

8. The preparation method according to claim 7, characterized in that, In step (3), the volume ratio of H2 to N2 is 1:9, the gradient heating refers to heating at a rate of 3 ℃ / min to 250 ℃, and the reduction time is 4 hours.

9. A palladium-based catalyst for dehydrogenation prepared by the preparation method of any one of claims 1-8.

10. The use of the palladium-based catalyst for dehydrogenation according to claim 9 in a catalytic dehydrogenation reaction of a hydrogen-containing gas, characterized in that, The hydrogen-containing gas includes natural gas crude gas for helium extraction, fuel cell tail gas, or chemical pool off-gas.

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