Carbon dioxide assisted dehydrogenation catalyst and preparation method thereof

Abstract

The application discloses a carbon dioxide assisted dehydrogenation catalyst and a preparation method thereof. The catalyst comprises a honeycomb matrix, a modified silicon-aluminum coating on the surface of the honeycomb matrix and a first active component Pt, and the coating contains a group VIB metal carbide. Characteristic peaks representing the group VIB metal carbide appear at positions of 36°, 42°, 61° and 74° in an XRD spectrum, and lattice shift occurs. The preparation method comprises the following steps: (1) dissolving a group VIB metal precursor and / or an auxiliary metal salt in water to obtain solution A; (2) mixing alumina powder, pseudo-boehmite, a surfactant, a silicon source and the solution A to obtain a slurry; (3) loading the slurry on the honeycomb matrix, drying and roasting to obtain a carrier; and (4) loading Pt on the carrier to obtain the catalyst. The catalyst has a double active center synergistic cooperation function, has a double function of activating carbon dioxide and alkane dissociation adsorption, and has a wide application prospect in the fields of selective oxidation, oxidative dehydrogenation and the like.

Description

Technical Field

[0001] This invention belongs to the field of catalyst preparation, specifically relating to a carbon dioxide-assisted dehydrogenation catalyst and its preparation method. Background Technology

[0002] Oxidative dehydrogenation of hydrocarbons can produce high-value-added olefin products. Compared with the traditional steam cracking method for obtaining olefins, oxidative dehydrogenation has low investment costs, single and easy-to-separate products, low energy consumption, no carbon buildup, and is not limited by thermodynamic equilibrium. Oxidative dehydrogenation generally uses oxygen as the oxidation source, but due to its strong oxidizing properties, it is easy to cause over-oxidation and reduce the selectivity of olefins. Therefore, the design of the reaction system is more complicated and the control is more difficult. For example, it is necessary to inject O2 at fixed points in the later stage of the pulse reactor. Compared with O2 as an oxidant, CO2 shows its unique advantages: (1) CO2 is a relatively mild oxidant. By controlling the reaction conditions, it can effectively inhibit the catalytic combustion of reactants (alkane) and the deep oxidation of intermediate products, thereby improving the selectivity of target products (olefins); (2) Using CO2 as an oxidant, direct mixing or co-feeding can be achieved in the existing direct dehydrogenation reactor, thereby saving equipment and process transformation costs, shortening the transformation cycle, and avoiding the uncertain start-up risks and possible pollution brought about by the transformation process. However, the activity of CO2 is far less than that of O2. Therefore, how to activate CO2 in the catalytic system is a problem that must be solved when using it as an oxidant.

[0003] CN115041208A discloses a method for forming honeycomb-shaped boron nitride and its application in the oxidative dehydrogenation of low-carbon alkanes. The honeycomb-shaped boron nitride prepared by this method has ordered axial channels, increasing the effective utilization area. The resulting product is lightweight, has high mechanical strength, and high mass transfer efficiency, exhibiting excellent catalytic activity and stability in the catalytic conversion of low-carbon alkanes. However, this method involves mixing boron nitride powder with a binder, resulting in a lack of slurry during synthesis and limiting the ability to continuously load active centers. This restricts the upper limit of dehydrogenation capacity, and using oxygen as the oxidation source can easily lead to over-oxidation, reducing the selectivity for olefins. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a carbon dioxide-assisted dehydrogenation catalyst and its preparation method. The catalyst of this invention exhibits a synergistic effect of Pt and Group VIB metal carbides, which has the dual function of activating the dissociation and adsorption of carbon dioxide and alkanes, and has broad application prospects in selective oxidation, oxidative dehydrogenation and other fields.

[0005] The carbon dioxide-assisted dehydrogenation catalyst of the present invention comprises a honeycomb substrate, a modified silicon-aluminum coating on the surface of the honeycomb substrate, and a first active component Pt, wherein the modified silicon-aluminum coating contains a Group VIB metal carbide, preferably Mo and / or W; Pt is partially supported on the surface of the Group VIB metal carbide in atomic form; the characteristic peaks representing the Group VIB metal carbide appearing at 36°, 42°, 61° and 74° in the XRD pattern show lattice shift, with a shift angle of 1~2°.

[0006] In the carbon dioxide-assisted dehydrogenation catalyst of the present invention, the honeycomb matrix is ​​85wt%~92wt%, the modified silicon-aluminum coating is 5wt%~12wt%, and Pt is 0.1wt%~0.5wt% by weight; based on the weight of the coating, it includes: alumina is 79wt%~91wt%, silicon dioxide is 1wt%~3wt%, and group VIB metal carbides are 3wt%~8wt%.

[0007] The carbon dioxide-assisted dehydrogenation catalyst of the present invention may further include a second active component of Zn and / or Sn, wherein the Zn and / or Sn, calculated as oxides, is 0.3wt% to 1.5wt% based on the total weight of the catalyst.

[0008] In the carbon dioxide-assisted dehydrogenation catalyst of the present invention, the modified silicon-aluminum coating may also contain an additive, which is 5% to 10% based on oxides, and the additive is selected from one or more of cerium, lanthanum, zirconium, titanium, and vanadium.

[0009] The preparation method of the carbon dioxide-assisted dehydrogenation catalyst of the present invention includes the following steps: (1) Dissolve the Group VIB metal precursor and the metal salt with or without additives in water, and then add a certain proportion of alcohol to obtain solution A; (2) Mix alumina powder, boehmite, surfactant, silicon source and solution A evenly, adjust the pH value to 3~4 or the viscosity to 10~100 mpa·s to obtain slurry; (3) The pretreated honeycomb substrate is immersed in the slurry for a period of time, and after being taken out, the residual liquid is blown out of the channel, dried and calcined to obtain the carrier; (4) The support is immersed in a Pt-containing solution, then ammonia is added, and the mixture is left to stand at the reaction temperature for a period of time. After being removed, it is purged, dried, and calcined. Then it is reduced in a mixed atmosphere of methane and hydrogen to obtain a carbon dioxide-assisted dehydrogenation catalyst.

[0010] In the method of the present invention, the group VIB metal precursor in step (1) is a soluble metal salt of a group VIB metal, such as ammonium molybdate, molybdenum chloride, sodium molybdate, ammonium tungstate, sodium tungstate, potassium tungstate, etc.

[0011] In the method of the present invention, the auxiliary metal salt in step (1) is one or more of the soluble metal salts of cerium, lanthanum, zirconium, titanium, and vanadium.

[0012] In the method of the present invention, the alcohol mentioned in step (1) is one or more of ethanol, ethylene glycol or butanol; the mass ratio of alcohol to water is 1~2:20.

[0013] In the method of this invention, the specific surface area of ​​the alumina powder in step (2) is 100~1000 m². 2 / g; the specific surface area of ​​pseudoboehmite is 150~300m². 2 / g; the surfactant is one or more of polyethylene glycol, urea, sodium dodecylbenzenesulfonate and stearic acid; the silicon source is one or more of tetraethyl orthosilicate, methyl orthosilicate, polysiloxane, ethoxysiloxane and so on.

[0014] In the method of the present invention, step (2) generally uses a diluted inorganic acid solution to adjust the pH to obtain a slurry with a suitable viscosity, wherein the inorganic acid is generally hydrochloric acid or nitric acid.

[0015] In the method of the present invention, the slurry comprises, by total weight: 40wt% to 60wt% alcohol and water, 20wt% to 35wt% activated alumina powder, 3wt% to 5wt% boehmite, 0.5wt% to 2wt% group VIB metal precursor, 0wt% to 3wt% auxiliary metal salt, 3wt% to 5wt% surfactant, 3wt% to 5wt% silicon source, and 0.5wt% to 2wt% inorganic acid, wherein the sum of the contents of each component is 100%.

[0016] In the method of this invention, the pretreatment process described in step (2) is well known to those skilled in the art. Generally, the honeycomb substrate is acid-treated, then washed with water and dried for later use. The acid treatment generally involves soaking in dilute nitric acid or hydrochloric acid, preferably with simultaneous ultrasonic oscillation treatment for 10-60 minutes.

[0017] In the method of the present invention, the honeycomb substrate in step (2) is selected from at least one of cordierite honeycomb carrier, mullite honeycomb carrier, diamond honeycomb carrier, corundum honeycomb carrier, zirconium corundum honeycomb carrier, quartz honeycomb carrier, nepheline honeycomb carrier, feldspar honeycomb carrier, alumina honeycomb carrier and metal alloy honeycomb carrier.

[0018] In the method of the present invention, the impregnation time in step (3) is 2 to 10 minutes; the drying temperature is 100 to 150°C and the time is 12 to 24 hours; the calcination temperature is 400 to 550°C and the time is 2 to 4 hours.

[0019] In the method of this invention, the second active component Zn and / or Sn is preferably introduced before step (4), specifically as follows: the carrier is immersed in a solution containing the second active component Zn and / or Sn, left to stand for a period of time, then removed, washed with water, dried, and calcined to obtain a carrier containing the second active component Zn and / or Sn; the immersion time is 2-10 minutes; the drying temperature is 100-150℃, and the time is 12-24 hours; the calcination temperature is 400-550℃, and the time is 2-4 hours. The concentration of the solution containing the second active component Zn and / or Sn is 0.16-0.5 mol / L. For example, zinc acetate or tin chloride solution can be used.

[0020] In the method of this invention, the concentration of the Pt-containing solution in step (4) is 0.01~0.03 mol / L. The Pt-containing solution is generally prepared using Pt nitrate or chlorate.

[0021] In the method of the present invention, the impregnation time in step (4) is 2 to 10 minutes; the drying temperature is 100 to 150°C and the time is 12 to 24 hours; the calcination temperature is 400 to 550°C and the time is 2 to 4 hours.

[0022] In the method of the present invention, step (4) involves adding concentrated ammonia to adjust the pH to 8-9, the reaction temperature to 60-70℃, and the standing time to 1-4 hours.

[0023] In the method of the present invention, the purging process described in step (4) generally involves purging with dry air until there is no residual liquid in the channel.

[0024] In the method of this invention, in step (4), the methane and hydrogen mixture has a methane volume percentage of 5% to 15% and the remainder is hydrogen, with a space velocity of 100 to 1000 h⁻¹. -1 .

[0025] In the method of the present invention, the reduction conditions in step (4) are: reduction temperature of 550~650 ℃ and reduction time of 0.5~1.5 hours.

[0026] The application of the carbon dioxide-assisted dehydrogenation catalyst of this invention in the coupled reaction of carbon dioxide utilization and oxidative dehydrogenation generally operates under the following conditions: reaction pressure of 0.1~1.5 MPa, reaction temperature of 400~650℃, and gas hourly space velocity of 5~200 h⁻¹. -1 .

[0027] This catalyst utilizes molybdenum carbide / tungsten as the catalytic center for CO2 activation, assisting the noble metal Pt in the dehydrogenation reaction. A Group VIB metal carbide precursor is coated onto a honeycomb ceramic support using a slurry, while Pt is simultaneously loaded onto the support via impregnation. After reduction with a methane and hydrogen mixture, dual active centers of Pt and Group VIB metal carbides are obtained. Consequently, some Pt ​​is tightly bonded to the Group VIB metal carbides, with Pt directly bonded to and loaded onto the Group VIB metal carbides. The active centers obtained through this method are located both within and on the coated support, making aggregation during the reaction less likely. Pt is responsible for alkane dehydrogenation, while the Group VIB metal carbides are responsible for CO2 activation. Due to the close structural proximity of the two active centers, hydrogen removed from Pt can quickly find and be adsorbed by CO2 to generate oxygen, completing the reaction chain and improving the catalyst's reaction efficiency. The synthesized catalyst has broad application prospects in selective oxidation and other fields. The catalyst of this invention has the advantages of strong mass and heat transfer capabilities, low pressure drop, narrow residence time distribution, and easy replacement, avoiding potential problems such as carbon buildup in catalysts. Attached Figure Description

[0028] Figure 1 This is a transmission electron microscope (TEM) image of the catalyst prepared in Example 1 of the present invention.

[0029] Figure 2 The XRD patterns of the catalyst, pure molybdenum carbide, and support prepared in Example 1 of this invention are shown. Detailed Implementation

[0030] The technical solutions and effects of the present invention will be further illustrated below with reference to the embodiments, but the invention is not limited to the following embodiments.

[0031] This invention utilizes TEM to observe the relationship between Pt and Mo2C in a sample. A JEOL JEM-F200 field emission transmission electron microscope was used. Operating conditions: accelerating voltage 200 kV. Before testing, a small amount of powdered sample was ultrasonically dispersed in anhydrous ethanol and then dropped onto a copper grid using a capillary tube. After drying, the sample was tested.

[0032] This invention uses X-ray diffraction (XRD) to determine the bulk crystal structure of samples. A SmartLab 9 kW powder X-ray diffractometer from Rigaku Corporation, Japan, was used. The operating conditions were as follows: Cu Kα ray source (wavelength λ = 1.5406 Å), tube voltage 45 kV, tube current 200 mA, scan range 5°–80°, scan speed 10 ° min⁻¹, step size 0.02 °, and a 1D D / teX detector (defluorinated mode). Example 1

[0033] (1) Dissolve 3g of cerium nitrate and 6g of ammonium molybdate in 170g of water; (2) The solution obtained in step (1) is mixed with alumina powder, urea and boehmite in a mass ratio of 170:90:10:10 and stirred for 6 hours to obtain a mixed slurry; (3) Add 18g butanol to the mixed slurry and then stir for 1 hour; (4) Add 10g of tetraethyl orthosilicate to the mixed slurry obtained in step (3), and then stir for 1 hour; add 5g of concentrated nitric acid, and then stir for 1 hour; (5) Immerse the pretreated honeycomb ceramic in the slurry in step (4) for 5 minutes, remove it and blow the slurry residue out of the channel. Dry the loaded honeycomb ceramic in an oven at 110°C for 12 hours, and then calcine it in a muffle furnace at 500°C for 2 hours to obtain the carrier. The pretreatment process is as follows: put 100 mL of honeycomb ceramic into 200 mL of 1 mol / L nitric acid solution and vibrate it in an ultrasonic oscillator for 1 hour. Then rinse it repeatedly with 500 mL of water and dry it in an oven at 110°C for 12 hours. (6) The carrier was immersed in a 120 mL solution of zinc acetate with a concentration of 0.36 mol / L and citric acid of 0.3 mol / L. After immersion for 5 minutes, it was taken out and washed with water, dried at 110°C for 12 hours, and calcined at 400°C for 2 hours to obtain a carrier containing Zn. (7) The carrier containing Zn was immersed in a 0.015 mol / L solution of 150 mL of platinum nitrate, concentrated ammonia was added to adjust the pH to 9, and then the solution was left to stand for 2 hours. (8) Remove the impregnated carrier, purge with dry air for 2 hours, dry in an oven at 110°C for 12 hours, then calcine in a muffle furnace at 450°C for 4 hours, transfer to a tube furnace, and use a mixture of methane and hydrogen (methane volume percentage 10%, the remainder being hydrogen, space velocity 200 h⁻¹) -1 The temperature was increased by programmed reduction, which was carried out at a rate of 1℃ / min from room temperature to 550℃ to obtain the catalyst Pt-Mo2C-1.

[0034] The product powder was characterized using TEM (transmission electron microscopy). Figure 1 The parallel lines with intervals (the interval distance is related to the exposed crystal plane, for example, 0.246 nm for the 111 crystal plane) can be clearly seen. These parallel line groups are individual molybdenum carbide particles, and there are obvious darker black Pt metal particles on the particles. Example 2

[0035] (1) Dissolve 3g of lanthanum nitrate and 7g of ammonium molybdate in 170g of water; (2)~(6) The process of preparing the slurry is the same as in Example 1; (7) The carrier was immersed in a 0.02 mol / L, 150 mL platinum nitrate solution, concentrated ammonia was added to adjust the pH to 8, and then it was left to stand for 3 hours. (8) Remove the impregnated carrier, purge with dry air for 2 hours, then dry in an oven at 110°C for 12 hours, then calcine in a muffle furnace at 450°C for 4 hours, and transfer to a tube furnace using a mixture of methane and hydrogen (methane volume percentage 10%, the remainder being hydrogen, space velocity 200 h⁻¹). -1 The temperature was increased by programmed temperature rise, which was carried out at a rate of 1℃ / min from room temperature to 600℃ to obtain the catalyst Pt-Mo2C-2. Example 3

[0036] Similar to Example 2, but with a different reduction process: a mixture of methane and hydrogen (methane accounting for 5% by volume, the remainder being hydrogen, with a space velocity of 100 h⁻¹) was used. -1 The temperature was increased by programmed reduction, which was carried out at a rate of 1℃ / min from room temperature to 650℃ to obtain the catalyst Pt-Mo2C-3. Example 4

[0037] Same as Example 2, except that butanol is replaced with ethylene glycol in step (3); thus, catalyst Pt-Mo2C-4 is obtained. Example 5

[0038] Same as Example 1, except that 6g of ammonium molybdate was replaced with 14.5g of ammonium tungstate; thus, the catalyst Pt-W2C was obtained. Example 6

[0039] Example 1, except that step 6 is omitted, and the carrier obtained in step 5 is directly loaded with Pt in step 7. This yields Pt-Mo2C-5.

[0040] Comparative Example 1 Same as Example 1, except that in step (8) it is not a mixture of methane and hydrogen, but pure hydrogen; thus, the catalyst Pt-Mo2C-6 is obtained.

[0041] Comparative Example 2 Same as Example 2, except that in step (8) the gas is pure nitrogen instead of a mixture of methane and hydrogen; thus, the catalyst Pt-Mo2C-7 is obtained.

[0042] Comparative Example 3 Same as Example 1, except that the temperature is increased to 300°C in step (8); thus, the catalyst Pt-Mo2C-8 is obtained.

[0043] Comparative Example 4 Same as Example 1, except that cerium nitrate was not added; thus, the catalyst Pt-Mo2C-9 was obtained.

[0044] Comparative Example 5 Same as Example 1, except that tetraethyl orthosilicate was not added to the coating slurry; thus, the catalyst Pt-Mo2C-10 was obtained.

[0045] Comparative Example 6 Same as Example 1, except that the loading process of Pt is changed to step (7): the support is immersed in a 0.48 mol / L, 100 mL platinum nitrate solution for 5 minutes to obtain the catalyst Pt-Mo2C-11. Example 7

[0046] The catalysts used in the examples and comparative examples were applied to the catalytic oxidation of ethane in a fixed-bed reactor of a medium-sized reaction evaluation device. The catalyst loading was 100 mL, the bed height was 10 cm, the initial propane concentration was 25% (v / v), the initial carbon dioxide concentration was 25% (v / v), the carrier gas was nitrogen, the reaction pressure was 0.1 MPa, the reaction temperature was 550 °C, and the space velocity was 50 h⁻¹. -1 Propane and propylene were measured using an Agilent 7890A gas chromatograph, and the catalyst evaluation results are shown in Table 1.

[0047] Table 1 Catalyst Evaluation Results

Claims

1. A carbon dioxide-assisted dehydrogenation catalyst, characterized in that: The product includes a honeycomb substrate, a modified silicon-aluminum coating on the surface of the honeycomb substrate, and a first active component Pt. The modified silicon-aluminum coating contains group VIB metal carbides. Pt is partially loaded on the surface of the group VIB metal carbides in atomic form. The characteristic peaks representing group VIB metal carbides appearing at 36°, 42°, 61°, and 74° in the XRD pattern show lattice shifts with shift angles of 1 to 2°.

2. The catalyst according to claim 1, characterized in that: Based on the total weight of the catalyst, the honeycomb matrix accounts for 85wt%~92wt%, the modified silica-alumina coating accounts for 5wt%~12wt%, and Pt accounts for 0.1wt%~0.5wt% (elementally). Based on the weight of the coating, it includes: 79wt%~91wt% alumina, 1wt%~3wt% silicon dioxide, and 3wt%~8wt% group VIB metal carbides; the group VIB metal is preferably Mo and / or W.

3. The catalyst according to claim 1, characterized in that: The catalyst includes a second active component of Zn and / or Sn, with Zn and / or Sn accounting for 0.3wt% to 1.5wt% as oxides based on the total weight of the catalyst, and the sum of the contents of each component is 100%.

4. The catalyst according to claim 1, characterized in that: The modified silicon-aluminum coating also contains additives, which are 5% to 10% based on oxides. The additives are selected from one or more of cerium, lanthanum, zirconium, titanium, or vanadium.

5. A method for preparing a carbon dioxide-assisted dehydrogenation catalyst according to any one of claims 1 to 4, characterized in that... The following are included: (1) Dissolve the Group VIB metal precursor and / or auxiliary metal salt in water, and then add a certain proportion of alcohol to obtain solution A; (2) Mix alumina powder, boehmite, surfactant, silicon source and solution A evenly, adjust the pH value to 3~4 or the viscosity to 10~100 mpa·s to obtain slurry; (3) Immerse the pretreated honeycomb substrate in the slurry for a period of time, take it out and blow the residual liquid out of the channel, dry and calcine to obtain the carrier; (4) Immerse the carrier in a Pt-containing solution, then add ammonia water, let it stand at the reaction temperature for a period of time, take it out and blow it, dry and calcine, and then reduce it in a mixed atmosphere of methane and hydrogen to obtain carbon dioxide-assisted dehydrogenation catalyst.

6. The method according to claim 5, characterized in that: The group VIB metal precursor in step (1) is a soluble metal salt of a group VIB metal, preferably one or more of ammonium molybdate, molybdenum chloride, sodium molybdate, ammonium tungstate, sodium tungstate, and potassium tungstate.

7. The method according to claim 5, characterized in that: The auxiliary metal salt mentioned in step (1) is one or more of the soluble metal salts of cerium, lanthanum, zirconium, titanium, and vanadium.

8. The method according to claim 5, characterized in that: The alcohol mentioned in step (1) is one or more of ethanol, ethylene glycol or butanol; the mass ratio of alcohol to water is 1~2:

20.

9. The method according to claim 5, characterized in that: The specific surface area of ​​the alumina powder in step (2) is 100~1000 m². 2 / g; the specific surface area of ​​pseudoboehmite is 150~300m². 2 / g; the surfactant is one or more of polyethylene glycol, urea, sodium dodecylbenzenesulfonate and stearic acid; the silicon source is one or more of tetraethyl orthosilicate, methyl orthosilicate, polysiloxane and ethoxysiloxane.

10. The method according to claim 5, characterized in that: The slurry comprises, by total weight: 40wt% to 60wt% alcohol and water, 20wt% to 35wt% activated alumina powder, 3wt% to 5wt% boehmite, 0.5wt% to 2wt% group VIB metal precursor, 0wt% to 3wt% auxiliary metal salt, 3wt% to 5wt% surfactant, 3wt% to 5wt% silicon source, and 0.5wt% to 2wt% inorganic acid, wherein the sum of the contents of each component is 100%.

11. The method according to claim 5, characterized in that: The honeycomb substrate mentioned in step (2) is selected from at least one of cordierite honeycomb carrier, mullite honeycomb carrier, diamond honeycomb carrier, corundum honeycomb carrier, zirconium corundum honeycomb carrier, quartz honeycomb carrier, nepheline honeycomb carrier, feldspar honeycomb carrier, alumina honeycomb carrier and metal alloy honeycomb carrier.

12. The method according to claim 5, characterized in that: The soaking time in step (3) is 2 to 10 minutes; the drying temperature is 100 to 150°C and the time is 12 to 24 hours; the calcination temperature is 400 to 550°C and the time is 2 to 4 hours.

13. The method according to claim 5, characterized in that: The Zn and / or Sn second active component is introduced before step (4), specifically: the carrier is immersed in a solution containing the Zn and / or Sn second active component, left to stand for a period of time, then taken out, washed with water, dried and calcined to obtain a carrier containing the Zn and / or Sn second active component; the immersion time is 2~10 minutes; the drying temperature is 100~150℃ and the time is 12~24 hours; the calcination temperature is 400~550℃ and the time is 2~4 hours; the concentration of the solution containing the Zn and / or Sn second active component is 0.16~0.5mol / L.

14. The method according to claim 5, characterized in that: The concentration of the Pt-containing solution in step (4) is 0.01~0.03 mol / L.

15. The method according to claim 5, characterized in that: The soaking time in step (4) is 2 to 10 minutes; the drying temperature is 100 to 150°C and the time is 12 to 24 hours; the calcination temperature is 400 to 550°C and the time is 2 to 4 hours.

16. The method according to claim 5, characterized in that: Step (4) Add concentrated ammonia to adjust the pH to 8-9, the reaction temperature is 60-70℃, and the standing time is 1-4 hours.

17. The method according to claim 5, characterized in that: In step (4), the methane and hydrogen mixture has a volume percentage of 5% to 15% methane and the remainder is hydrogen, with a space velocity of 100 to 1000 h⁻¹. -1 .

18. The method according to claim 5, characterized in that: The reduction conditions in step (4) are: reduction temperature of 550~650 ℃ and reduction time of 0.5~1.5 hours.

19. The application of the carbon dioxide-assisted dehydrogenation catalyst according to any one of claims 1 to 4 in the coupled reaction of carbon dioxide utilization and oxidative dehydrogenation, wherein the operating conditions are: reaction pressure of 0.1 to 1.5 MPa, reaction temperature of 400 to 650 °C, and gas hourly space velocity of 5 to 200 h⁻¹. -1 .

Images