Preparation method of cobalt molybdenum oxide catalyst and method for preparing propylene by catalyzing oxidative dehydrogenation of propane
By preparing cobalt-molybdenum oxide catalysts, the problems of high energy consumption and low selectivity of ODHP catalysts have been solved, achieving high selectivity and low cost in the low-temperature oxidative dehydrogenation of propane to propylene, which is applicable to the fields of thermocatalytic materials and environmental protection technology.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JIANGSU UNIV OF SCI & TECH
- Filing Date
- 2026-03-26
- Publication Date
- 2026-05-12
AI Technical Summary
Existing ODHP catalysts suffer from high energy consumption and low olefin selectivity in the oxidative dehydrogenation of propane to propylene. In particular, nickel-based and vanadium-based catalysts require high temperatures, while cobalt-based and molybdenum-based catalysts have room for improvement in terms of low-temperature activation and selectivity.
A CoMo/γ-Al2O3 catalyst was formed by mixing cobalt nitrate hexahydrate and sodium molybdate dihydrate with AlOOH powder, ball milling and calcining, using a cobalt-molybdenum oxide catalyst. This optimized the dispersibility and interaction of the active components and reduced the reaction temperature.
It achieves high selectivity and low cost for propane oxidative dehydrogenation to propylene under low temperature conditions, and the catalyst has a stable structure and is easy to industrialize.
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Abstract
Description
Technical Field
[0001] This invention relates to a catalyst, specifically a cobalt-molybdenum oxide catalyst, and also to a method for preparing the cobalt-molybdenum oxide catalyst, belonging to the fields of thermocatalytic materials and environmental protection technology. Background Technology
[0002] Propylene is a key raw material for three major synthetic materials—plastics, rubber, and chemical fibers—and the market demand for its derivatives continues to grow rapidly. Currently, industrial propylene production mainly relies on steam cracking and fluidized bed catalytic cracking processes using petroleum byproducts (such as naphtha and light diesel oil), as well as direct propane dehydrogenation. With the decreasing cost of alkane extraction from shale gas, oxidative dehydrogenation of propane (ODHP) has attracted increasing attention due to its advantages such as low energy consumption, low carbon buildup, and significant thermodynamic advantages. However, inhibiting deep oxidation and improving catalyst activity and olefin selectivity remain key challenges that need to be addressed for this technology to achieve industrialization.
[0003] In ODHP catalyst systems, transition metal oxides dominate, mainly including V-based, Cr-based, Ni-based, Mo-based, and rare earth-based types. While nickel-based and vanadium-based catalysts can achieve high propylene selectivity, they typically require high reaction temperatures (>500℃) and consume significant energy. In recent years, cobalt-based and molybdenum-based catalysts have also shown unique advantages in ODHP reactions. Cobalt-based catalysts, due to their abundant oxygen species and tunable redox properties, excel in promoting propane CH bond activation and often exhibit a low tendency for complete oxidation. Molybdenum-based catalysts are known for their excellent propylene selectivity and resistance to carbon deposition. Combining the low-temperature activation characteristics of cobalt with the selectivity advantages of molybdenum to construct a multi-metal synergistic catalytic system has become an important direction in current ODHP catalyst design. Therefore, this study uses molybdenum doped into a cobalt oxide catalyst to create a cobalt-molybdenum oxide catalyst, achieving low-temperature catalytic oxidative dehydrogenation of propane to propylene. Summary of the Invention
[0004] To address the aforementioned problems, the present invention aims to provide a method for preparing a cobalt-molybdenum oxide catalyst that exhibits high selectivity for the oxidative dehydrogenation of propane to propylene under low-temperature conditions, based on the current challenges faced by transition metal-based catalysts.
[0005] To achieve the above objectives, the first technical solution provided by the present invention is as follows: A method for preparing a cobalt-molybdenum oxide catalyst includes the following steps: (1) Prepare an aqueous solution of cobalt nitrate hexahydrate using cobalt nitrate hexahydrate; (2) Add sodium molybdate dihydrate to the cobalt nitrate hexahydrate aqueous solution and stir at room temperature for 30 min; (3) Add the mixed solution dropwise and slowly onto the AlOOH powder while stirring; (4) Place the mixed paste into a ball mill jar and ball mill for 4 hours; (5) Centrifuge and dry to obtain a solid product; (6) The above solid product is calcined in air to obtain the finished product; it belongs to the fields of thermocatalytic materials and environmental protection technology.
[0006] Furthermore, in the preparation method of the above cobalt-molybdenum oxide catalyst, the cobalt nitrate hexahydrate aqueous solution mentioned in step (1) can be obtained by adding 0.68 mmol of cobalt nitrate hexahydrate to 25 mL of water.
[0007] Furthermore, in the preparation method of the above cobalt-molybdenum oxide catalyst, the mixed solution mentioned in step (2) can be obtained by adding 0.34 mmol of sodium molybdate dihydrate to an aqueous solution of cobalt nitrate hexahydrate.
[0008] Furthermore, in the preparation method of the above cobalt-molybdenum oxide catalyst, the ratio of the mixed solution to the powder in step (3) is 1 ml: 1 g.
[0009] Furthermore, in the preparation method of the above cobalt-molybdenum oxide catalyst, the ball mill parameters in step (4) are: 500 r / min and 4h.
[0010] Furthermore, in the preparation method of the above cobalt-molybdenum oxide catalyst, the centrifugation parameters in step (5) are: 10000 r / min, time 5 min; the washing conditions are: washing once with deionized water; the drying temperature is 60℃, and the time is 12 h.
[0011] Furthermore, in the above-mentioned method for preparing cobalt-molybdenum oxide catalyst, the calcination temperature in step (6) is 500℃ and the calcination time is 4h.
[0012] The second technical solution provided by the present invention is a cobalt-molybdenum oxide catalyst prepared by the above method.
[0013] The catalyst is used in a method for catalyzing the oxidative dehydrogenation of propane to produce propylene. The catalytic conditions are as follows: the feed gas composition is 5% propane, 4% oxygen, the equilibrium gas is nitrogen, the space velocity is 5200 mL / (g·h), and the reaction temperature is 180-200℃.
[0014] The CoMo / γ-Al2O3 catalyst provided by this invention is applied in the field of thermocatalysis.
[0015] Compared with the prior art, the technical solution provided by the present invention has the following specific technical advantages: Using non-precious metals cobalt and molybdenum, as well as commercially available AlOOH, as supports, the raw material costs are low, the preparation process is simple, and the overall cost of the catalyst is significantly reduced. By optimizing the preparation process, the cobalt and molybdenum active components were highly dispersed and strongly interacted on the γ-Al2O3 surface, forming abundant and stable active centers, which synergistically improved the ability of low-temperature propane activation and propylene selective generation.
[0016] The catalyst has a stable structure, the preparation method has good reproducibility and scalability, the process conditions are mild and the operation is simple, making it easy to achieve industrial-scale production. Attached Figure Description
[0017] Figure 1 The propylene selectivity curve for the CoMo / γ-Al2O3 catalyst is shown. Figure 2 The graph shows the propane conversion rate of the CoMo / γ-Al2O3 catalyst. Figure 3 Schematic diagram of the synthesis of CoMo / γ-Al2O3 catalyst; Figure 4 Scanning electron microscope (SEM) of CoMo / γ-Al2O3; Detailed Implementation
[0018] The technical solution of the present invention will be described in detail below through specific embodiments. However, it should be clearly stated that these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention. Example
[0019] This embodiment provides a method for preparing a CoMo / γ-Al2O3 catalyst for the thermocatalytic oxidative dehydrogenation of propane to propylene, which is prepared by the following method: Take 0.197g of Co(NO3)2⋅6H2O and add it to 25mL of deionized water to obtain a cobalt nitrate hexahydrate aqueous solution; Take 0.345g of Na2MoO4⋅2H2O and add it to the cobalt nitrate hexahydrate aqueous solution. Stir the above solution on a magnetic stirrer for 30 minutes. The mixed solution was added dropwise and slowly onto the AlOOH powder while stirring. The resulting paste was placed in a ball mill and ball milled at 500 r / min for 4 h. Centrifugation, washing with deionized water, and drying to obtain a solid product. Centrifugation parameters: 10000 r / min, time 5 min; washing conditions: one wash with deionized water; drying temperature: 60℃, time: 12 h. The above solid product was calcined in air at a temperature of 500°C for 4 hours to obtain the final product. The resulting sample is designated as M2C1A. Example
[0020] This embodiment provides a method for preparing a CoMo / γ-Al2O3 catalyst for the thermocatalytic oxidative dehydrogenation of propane to propylene, which is prepared by the following method: Take 0.197g of Co(NO3)2⋅6H2O and add it to 25mL of deionized water to obtain a cobalt nitrate hexahydrate aqueous solution; Take 0.655g of Na2MoO4⋅2H2O and add it to the cobalt nitrate hexahydrate aqueous solution. Stir the above solution on a magnetic stirrer for 30min. The mixed solution was added dropwise and slowly onto the AlOOH powder while stirring. The resulting paste was placed in a ball mill and ball milled at 500 r / min for 4 h. Centrifugation, washing with deionized water, and drying to obtain a solid product. Centrifugation parameters: 10000 r / min, time 5 min; washing conditions: one wash with deionized water; drying temperature: 60℃, time: 12 h. The above solid product was calcined in air at a temperature of 500°C for 4 hours to obtain the final product. The resulting sample is designated as M4C1A. Example
[0021] This embodiment provides a method for preparing a CoMo / γ-Al2O3 catalyst for the thermocatalytic oxidative dehydrogenation of propane to propylene, which is prepared by the following method: Take 0.197g Co(NO3)2⋅6H2O and add it to 25mL of deionized water to obtain a cobalt nitrate hexahydrate aqueous solution. Stir the above solution on a magnetic stirrer for 30min. The resulting solution was added dropwise and slowly onto the AlOOH powder while stirring. The resulting paste was placed in a ball mill and ball milled at 500 r / min for 4 h. Centrifugation, washing with deionized water, and drying to obtain a solid product. Centrifugation parameters: 10000 r / min, time 5 min; washing conditions: one wash with deionized water; drying temperature: 60℃, time: 12 h. The above solid product was calcined in air at a temperature of 500°C for 4 hours to obtain the final product. The resulting sample is designated as CoA. Example
[0022] This embodiment provides a method for preparing a CoMo / γ-Al2O3 catalyst for the thermocatalytic oxidative dehydrogenation of propane to propylene, which is prepared by the following method: Add 0.345g of Na2MoO4⋅2H2O to 25mL of deionized water and stir the solution on a magnetic stirrer for 30min. The resulting solution was added dropwise and slowly onto the AlOOH powder while stirring. The resulting paste was placed in a ball mill and ball milled at 500 r / min for 4 h. Centrifugation, washing with deionized water, and drying to obtain a solid product. Centrifugation parameters: 10000 r / min, time 5 min; washing conditions: one wash with deionized water; drying temperature: 60℃, time: 12 h. The above solid product was calcined in air at a temperature of 500°C for 4 hours to obtain the final product. The resulting sample is designated as MoA.
Claims
1. A method for preparing a cobalt-molybdenum oxide catalyst, characterized in that, The steps are as follows: (1) Prepare an aqueous solution of cobalt nitrate hexahydrate using cobalt nitrate hexahydrate; (2) Add sodium molybdate dihydrate to the cobalt nitrate hexahydrate aqueous solution and stir at room temperature for 30 min; (3) Add the mixed solution dropwise and slowly onto the AlOOH powder while stirring; (4) Place the mixed paste into a ball mill jar and ball mill for 4 hours; (5) Centrifuge and dry to obtain a solid product; (6) The above solid product is calcined in air atmosphere to obtain the finished product; It belongs to the fields of thermocatalytic materials and environmental protection technology.
2. The method for preparing the cobalt-molybdenum oxide catalyst according to claim 1, characterized in that, The cobalt nitrate hexahydrate aqueous solution mentioned in step (1) can be obtained by adding 0.68 mmol of cobalt nitrate hexahydrate to 25 mL of water.
3. The method for preparing the cobalt-molybdenum oxide catalyst according to claim 1, characterized in that, The mixed solution mentioned in step (2) can be obtained by adding 0.34 mmol of sodium molybdate dihydrate to an aqueous solution of cobalt nitrate hexahydrate.
4. The method for preparing the cobalt-molybdenum oxide catalyst according to claim 1, characterized in that, The ratio of the mixed solution to the powder in step (3) is 1 ml: 1 g.
5. The method for preparing the cobalt-molybdenum oxide catalyst according to claim 1, characterized in that, In step (4), the ball mill parameters are: 500 r / min and 4h.
6. The method for preparing the cobalt-molybdenum oxide catalyst according to claim 1, characterized in that, In step (5), the centrifugation parameters are: 10000 r / min, time 5 min; the washing conditions are: wash once with deionized water; the drying temperature is 60℃, and the time is 12 h.
7. The method for preparing the cobalt-molybdenum oxide catalyst according to claim 1, characterized in that, In step (6), the calcination temperature is 500℃ and the calcination time is 4h.
8. A cobalt-molybdenum oxide catalyst, characterized in that, Prepared using the method described in any one of claims 1-7.
9. A method for producing propylene by catalytic oxidative dehydrogenation of propane using the cobalt-molybdenum oxide catalyst as described in claim 8, characterized in that, The catalytic conditions are as follows: the feed gas composition is 5% propane, 4% oxygen, the equilibrium gas is nitrogen, the space velocity is 5200 mL / (g·h), and the reaction temperature is 150-210℃.
10. The cobalt-molybdenum oxide catalyst provided by this invention is applied in the field of thermocatalysis. The catalyst exhibits certain catalytic efficiency for monomeric small-molecule organic compounds and can be used to degrade common organic pollutants in the air.