Copper-based bimetallic oxide supported catalyst for complete decomposition and dehydrogenation of methanol as well as preparation method and application of copper-based bimetallic oxide supported catalyst

Abstract

The invention discloses a copper-based bimetallic oxide supported catalyst for complete decomposition and dehydrogenation of methanol and a preparation method and application thereof.The method comprises the following steps that S1, copper salt, transition metal salt and an oxide carrier are added into ultrapure water, and after sufficient stirring is conducted at the room temperature, standing is conducted to obtain a copper-based bimetallic oxide supported catalyst; a mixture precipitate containing the bimetallic salt and the oxide carrier is obtained; s2, transferring the supernate obtained in the step S1 and the mixture precipitate into a blast drying oven, drying for a period of time within a certain temperature range, and fully grinding the precipitated powder after drying to obtain a copper-based bimetallic salt loaded precursor; and S3, placing the copper-based bimetallic salt loaded precursor in a tubular furnace, and carrying out oxidation treatment at a certain temperature in an air atmosphere to obtain the copper-based bimetallic oxide loaded catalyst, the method has the advantages of simple operation, low raw material price and the like, and the catalyst obtains high hydrogen production activity and reaction stability at high temperature.

Description

Technical Field

[0001] The invention belongs to the technical field of catalytic methanol hydrogen production, and specifically relates to a copper-based bimetallic oxide supported catalyst for complete decomposition and dehydrogenation of methanol, and a preparation method and application thereof. Background Art

[0002] Hydrogen energy is gradually being considered as a powerful alternative to fossil energy due to its unique advantages. As a clean secondary energy source, hydrogen has broad application prospects. There are many methods for producing hydrogen at present, including hydrogen production through natural gas conversion, coal gasification conversion, hydrogen production as a byproduct of the alkali process, and coke oven gas production as a byproduct of coking. Hydrogen can also be produced by generating electricity through renewable energy sources such as tidal energy, wind energy, and solar energy, and then produced by electrolyzing water to achieve carbon-free hydrogen production. The process is green and environmentally friendly and can be used for energy storage of renewable energy. The use of hydrogen energy has no carbon emissions and has good environmental benefits.

[0003] Hydrogen has a low volume energy density, a wide explosion limit and is prone to leakage, which is the main reason for the difficulty in hydrogen storage and transportation. Among the many solutions, the use of liquid raw materials for small-scale hydrogen production is expected to solve the problem of hydrogen storage and transportation. At the same time, it is more convenient and safer than long-distance transportation of hydrogen. Methanol, as the simplest liquid alcohol, has a simple structure and is liquid at room temperature and pressure. Compared with hydrogen, methanol is easy to transport and store, safer and easy to use. More importantly, methanol is easily obtained from biomass, can be completely biodegraded, and is also an important bulk chemical. Methanol can produce hydrogen through different reaction processes, such as complete decomposition dehydrogenation, water vapor reforming, partial oxidation reforming, etc. Among them, methanol complete decomposition dehydrogenation is the simplest and most widely used methanol hydrogen production method today, because it does not require any additional reactants. The complete decomposition reaction of methanol has been widely used in the field of internal combustion power devices. Internal combustion engines using methanol decomposition reactors can work under more stringent combustion conditions and have very important application prospects.

[0004] At present, there are two main types of catalysts used for complete decomposition and dehydrogenation of methanol: one is copper-based catalysts, such as CuO / ZnO / Al2O3, CuO / ZnO / ZrO2, etc.; and the other is non-copper-based catalysts, mainly including precious metal catalysts such as Pd / ZnO and non-precious metal-based catalysts such as Zn-CeO2. Precious metals cannot be produced on a large scale due to their high cost. Non-precious metal-based catalysts have been criticized by researchers due to their low catalytic activity. Based on previous related studies and the current problems of methanol complete decomposition and dehydrogenation reactions, the development of a catalyst with high activity, high stability and low cost has become a key issue in the field of methanol hydrogen production. At present, the development and design of high-temperature stability of copper-based catalysts are limited. The copper-based bimetallic oxide-supported catalyst has both the activity of copper-based catalysts and the stability of non-precious metal-based catalysts. It is a favorable way to solve the development of catalysts with high activity, high stability and low cost for catalytic complete decomposition and dehydrogenation of methanol. It is of great significance to achieve carbon peak and carbon neutrality as soon as possible, alleviate the current severe energy shortage and promote the development of hydrogen fuel. Summary of the invention

[0005] In order to solve the above problems, the present invention proposes a copper-based bimetallic oxide supported catalyst for complete decomposition and dehydrogenation of methanol, and a preparation method and application thereof.

[0006] The present invention adopts the following technical solutions:

[0007] A method for preparing a copper-based bimetallic oxide supported catalyst for complete decomposition and dehydrogenation of methanol comprises the following steps:

[0008] S1. Add a copper salt, a transition metal salt and an oxide carrier into ultrapure water, stir them thoroughly at room temperature, and let them stand to obtain a mixture precipitate containing a bimetallic salt and an oxide carrier; the mass ratio of the copper salt, the transition metal salt and the oxide carrier is (4-5):(2-4):10;

[0009] S2, transferring the supernatant obtained in step S1 and the mixed precipitate to a blast oven, drying them within a certain temperature range for a period of time, and fully grinding the precipitated powder after drying to obtain a copper-based bimetallic salt-loaded precursor;

[0010] S3. Placing the copper-based bimetallic salt-loaded precursor in a tubular furnace, and subjecting it to oxidation treatment at a certain temperature in an air atmosphere, thereby obtaining the copper-based bimetallic oxide-loaded catalyst.

[0011] Preferably, the copper salt in step S1 is one or more of copper nitrate and copper chloride.

[0012] Preferably, the transition metal salt in step S1 is one or more of nitrates or metal chlorides of transition metals such as iron, cobalt and nickel.

[0013] Preferably, the oxide carrier in step S1 is one or more of aluminum oxide and silicon oxide.

[0014] Preferably, the volume of ultrapure water in step S1 is 40-60 ml, and the stirring rate is 300-900 r / min.

[0015] Preferably, in step S2, the drying temperature is 70-90° C. and the drying time is 12-24 hours.

[0016] Preferably, the oxidation temperature of the oxidation treatment in step S3 is 400-600° C., and the oxidation time is 4-8 hours.

[0017] Preferably, the mass fraction of the copper element in the copper-based bimetallic oxide supported catalyst synthesized in step S3 is 8-12%, and the mass fraction of the other metal element is 4-6%.

[0018] A copper-based bimetallic oxide supported catalyst for complete decomposition and dehydrogenation of methanol is prepared by adopting the preparation method of the copper-based bimetallic oxide supported catalyst for complete decomposition and dehydrogenation of methanol.

[0019] Application of a copper-based bimetallic oxide supported catalyst for complete decomposition and dehydrogenation of methanol. The copper-based bimetallic oxide supported catalyst for complete decomposition and dehydrogenation of methanol is used as a catalyst for complete decomposition and dehydrogenation of methanol to prepare hydrogen. The catalytic conditions are: the reaction device used is a flow-type thermal catalytic reactor, the reaction temperature is 250-450°C, the reaction pressure is normal pressure, and the mass hourly space velocity of methanol liquid feed is 5-20h -1 , catalyst dosage 40-60mg.

[0020] After adopting the above technical solution, the present invention has the following advantages compared with the background technology:

[0021] 1. The present invention provides a method for preparing a copper-based bimetallic oxide supported catalyst for complete decomposition and dehydrogenation of methanol. The preparation method is simple, the raw materials are readily available, the cost is low and the reproducibility is good, and it can be applied to large-scale industrial production. The prepared copper-based bimetallic oxide supported catalyst has the advantages of excellent thermal stability and the like.

[0022] 2. The copper-based bimetallic oxide supported catalyst prepared by the present invention is applied to the complete decomposition and dehydrogenation reaction of methanol, and achieves a high hydrogen production activity at high temperature, which can expand its application in heat-driven hydrogen production from alcohols. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a hydrogen production performance diagram of the copper-based bimetallic oxide supported catalyst prepared in Examples 1, 2, 3, and 4 of the present invention applied to the complete decomposition and dehydrogenation reaction of methanol;

[0024] Figure 2 is a scanning electron microscope (SEM) image of the copper-based bimetallic oxide supported catalyst CuNi-Al2O3 prepared in Example 1 of the present invention;

[0025] Figure 3 The copper-based bimetallic oxide supported catalyst CuNi-Al2O3 prepared in Example 1 and the X-ray diffraction (XRD) pattern of the material after being placed in air for 60 days;

[0026] Figure 4 is an X-ray photoelectron spectroscopy (XPS) diagram of the copper-based bimetallic oxide supported catalyst CuNi-Al2O3 prepared in Example 1;

[0027] Figure 5 This is a graph showing the hydrogen production performance of the copper-based bimetallic oxide supported catalyst CuNi-Al2O3 prepared in Example 1 in the complete decomposition and dehydrogenation reaction of methanol at different temperatures;

[0028] Figure 6 This is a long-term performance diagram of the copper-based bimetallic oxide supported catalyst CuNi-Al2O3 prepared in Example 1 applied to the complete decomposition and dehydrogenation reaction of methanol. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0030] See also Figures 1 to 6 .

[0031] Example 1

[0032] The preparation of the CuNi-Al2O3 catalyst in this embodiment includes the following steps:

[0033] Step (1), first accurately weigh 0.4194 g of copper nitrate trihydrate, 0.248 g of nickel nitrate hexahydrate and 1 g of aluminum oxide, then add 40 ml of water, stir at room temperature at a speed of 600 r / min for 30 min, and fully mix and dissolve.

[0034] Step (2), after the stirring is completed, the obtained mixed solution is placed in an oven and dried at 90° C. for 12 hours, and the dried powder is ground to obtain a copper-based bimetallic salt-loaded precursor.

[0035] Step (3), placing the above-mentioned copper-based bimetallic salt-loaded precursor in a tubular furnace, introducing air, adjusting the air flow rate to 60 ml / min, heating to 500°C at a heating rate of 10°C / min and maintaining for 6 hours, and obtaining the CuNi-Al2O3 catalyst after calcination.

[0036] Example 2

[0037] The preparation of CuFe-Al2O3 catalyst in this embodiment includes the following steps:

[0038] Step (1), first accurately weigh 0.4194 g of copper nitrate trihydrate, 0.360 g of ferric nitrate nonahydrate and 1 g of aluminum oxide, then add 40 ml of water, stir at room temperature at a speed of 600 r / min for 30 min, and fully mix and dissolve.

[0039] Step (2), after the stirring is completed, the obtained mixed solution is placed in an oven and dried at 90° C. for 12 hours, and the dried powder is ground to obtain a precursor of the copper-based bimetallic salt-loaded oxide.

[0040] Step (3), placing the above-mentioned copper-based bimetallic salt-loaded precursor in a tubular furnace, introducing air, adjusting the air flow rate to 60 ml / min, heating to 500°C at a heating rate of 10°C / min and maintaining for 6 hours, and obtaining the CuFe-Al2O3 catalyst after calcination.

[0041] Example 3

[0042] The preparation of CuCo-Al2O3 catalyst in this embodiment includes the following steps:

[0043] Step (1), first accurately weigh 0.4194 g of copper nitrate trihydrate, 0.246 g of cobalt nitrate nonahydrate and 1 g of aluminum oxide, then add 40 ml of water, stir at room temperature at a speed of 600 r / min for 30 min, and fully mix and dissolve.

[0044] Step (2), after the stirring is completed, the obtained mixed solution is placed in an oven and dried at 90° C. for 12 hours, and the dried powder is ground to obtain a copper-based bimetallic salt-loaded precursor.

[0045] Step (3), placing the above-mentioned copper-based bimetallic salt-loaded precursor in a tubular furnace, introducing air, adjusting the air flow rate to 60 ml / min, heating to 500°C at a heating rate of 10°C / min and maintaining for 6 hours, and obtaining the CuCo-Al2O3 catalyst after calcination.

[0046] Example 4

[0047] This embodiment is the preparation of CuNi-SiO2, CuFe-SiO2, and CuCo-SiO2 catalysts. The preparation process of this embodiment is the same as that of Examples 1 to 3, except that 1g of aluminum oxide is replaced with 1g of silicon oxide.

[0048] Performance Test:

[0049] The copper-based bimetallic oxide supported catalysts obtained in Examples 1, 2, 3, and 4 were applied to the complete decomposition and dehydrogenation reaction of methanol. A flow-type thermal catalytic reactor was used. 50 mg of the catalyst was weighed into the reactor. The mass hourly space velocity of the methanol liquid feed was 20 h -1 The reaction temperature was 400℃, and the hydrogen production rate of methanol dehydrogenation reaction under different materials was tested. Figure 1 As shown, CuNi-Al2O3 has better hydrogen production performance than other materials.

[0050] The SEM image of the copper-based bimetallic oxide supported catalyst CuNi-Al2O3 obtained in Example 1 is as follows Figure 2 As shown, the sample is composed of a nano-granular structure supported on flaky aluminum oxide, with a size of less than 100 nm.

[0051] The X-ray diffraction test diagram of the copper-based bimetallic oxide supported catalyst CuNi-Al2O3 obtained in Example 1 is as follows Figure 3 As shown in the figure, the XRD of the CuNi-Al2O3 prepared by the above method has basically no change after being placed in the air for 60 days, indicating that CuNi-Al2O3 has good stability. Figure 4 As shown, the main peak of Cu 2p in CuNi-Al2O3 can be decomposed into Cu 1 / 2 and Cu 3 / 2 , located at 952.65eV and 932.95eV respectively, while the Ni element is Ni 2+ The XRD and XPS tests further confirmed that the present invention successfully synthesized the copper-based bimetallic oxide supported catalyst CuNi-Al2O3.

[0052] The copper-based bimetallic oxide supported catalyst obtained in Example 1 was applied to the complete decomposition and dehydrogenation reaction of methanol. A flow-type thermal catalytic reactor was used. 50 mg of the catalyst was weighed into the reactor. The mass hourly space velocity of methanol liquid feed was 20 h -1 The hydrogen production rate of methanol complete decomposition and dehydrogenation reaction at different temperatures was tested. Figure 5It can be seen that the hydrogen production rate of CuNi-Al2O3 gradually increases with the increasing temperature. When the temperature reaches 400℃, the hydrogen production rate of CuNi-Al2O3 can reach a platform and rise very slowly; and 50mg of catalyst is weighed in the reactor, and the mass hourly space velocity of methanol liquid feed is 5h -1 The reaction temperature is 400℃, and the long-term stability of CuNi-Al2O3 is tested. Figure 6 It can be seen that CuNi-Al2O3 can still maintain good hydrogen production performance after 120 hours, indicating that it has good stability as a thermal catalytic material in the complete decomposition and dehydrogenation reaction of methanol.

[0053] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for preparing a copper-based bimetallic oxide supported catalyst for complete decomposition and dehydrogenation of methanol, characterized in that: The steps include: S1. Add a copper salt, a transition metal salt and an oxide carrier into ultrapure water, stir them thoroughly at room temperature, and let them stand to obtain a mixture precipitate containing a bimetallic salt and an oxide carrier; the mass ratio of the copper salt, the transition metal salt and the oxide carrier is (4-5):(2-4):10; S2, transferring the supernatant obtained in step S1 and the mixed precipitate to a blast oven, drying them within a certain temperature range for a period of time, and fully grinding the precipitated powder after drying to obtain a copper-based bimetallic salt-loaded precursor; S3. Placing the copper-based bimetallic salt-loaded precursor in a tubular furnace, and subjecting it to oxidation treatment at a certain temperature in an air atmosphere, thereby obtaining the copper-based bimetallic oxide-loaded catalyst.

2. The method for preparing a copper-based bimetallic oxide supported catalyst for complete decomposition and dehydrogenation of methanol as claimed in claim 1, characterized in that: The copper salt in step S1 is one or more of copper nitrate and copper chloride.

3. The method for preparing a copper-based bimetallic oxide supported catalyst for complete decomposition and dehydrogenation of methanol as claimed in claim 1, characterized in that: The transition metal salt in step S1 is one or more of nitrates or metal chlorides of transition metals such as iron, cobalt and nickel.

4. The method for preparing a copper-based bimetallic oxide supported catalyst for complete decomposition and dehydrogenation of methanol as claimed in claim 1, characterized in that: The oxide carrier in step S1 is one or more of aluminum oxide and silicon oxide.

5. The method for preparing a copper-based bimetallic oxide supported catalyst for complete decomposition and dehydrogenation of methanol as claimed in claim 1, characterized in that: In step S1, the volume of ultrapure water is 40-60 ml, and the stirring rate is 300-900 r / min.

6. The method for preparing a copper-based bimetallic oxide supported catalyst for complete decomposition and dehydrogenation of methanol as claimed in claim 1, characterized in that: In step S2, the drying temperature is 70-90° C. and the drying time is 12-24 hours.

7. The method for preparing a copper-based bimetallic oxide supported catalyst for complete decomposition and dehydrogenation of methanol as claimed in claim 1, characterized in that: The oxidation temperature of the oxidation treatment in step S3 is 400-600° C., and the oxidation time is 4-8 hours.

8. The method for preparing a copper-based bimetallic oxide supported catalyst for complete decomposition and dehydrogenation of methanol as claimed in claim 1, characterized in that: The mass fraction of the copper element in the copper-based bimetallic oxide supported catalyst synthesized in step S3 is 8-12%, and the mass fraction of the other metal element is 4-6%.

9. A copper-based bimetallic oxide supported catalyst for complete decomposition and dehydrogenation of methanol, characterized in that: The catalyst is prepared by the method for preparing a copper-based bimetallic oxide supported catalyst for complete decomposition and dehydrogenation of methanol as described in any one of claims 1 to 8.

10. Use of the copper-based bimetallic oxide supported catalyst for complete decomposition and dehydrogenation of methanol as claimed in claim 9, characterized in that: The copper-based bimetallic oxide supported catalyst for complete decomposition and dehydrogenation of methanol is used as a catalyst for complete decomposition and dehydrogenation of methanol to prepare hydrogen. The catalytic conditions are: the reaction device used is a flow-type thermal catalytic reactor, the reaction temperature is 250-450° C., the reaction pressure is normal pressure, and the mass hourly space velocity of the methanol liquid feed is 5-20h -1 , catalyst dosage 40-60mg.

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