Copper-based catalyst for synthesizing methanol through carbon dioxide hydrogenation and preparation method of copper-based catalyst

Abstract

The invention discloses a copper-based catalyst for synthesizing methanol through hydrogenation of carbon dioxide and a preparation method thereof, and relates to the technical field of catalysts, the method comprises the following steps: providing a carrier mixed solution which comprises soluble ferric salt and aluminum salt; providing a precipitant solution, wherein the precipitant solution comprises sodium carbonate and sodium hydroxide; providing an active metal mixed solution, wherein the active metal mixed solution comprises soluble copper salt, soluble zinc salt and soluble metal additive salt; mixing the carrier mixed solution with the precipitant solution to obtain precipitate slurry; aging the precipitation slurry, and sequentially washing, drying and roasting to obtain a carrier; and mixing the carrier with the active metal mixed solution, and drying and roasting the mixture. The catalyst can improve the activation capacity of CO2 and inhibit sintering inactivation of Cu.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, in particular to a copper-based catalyst for synthesizing methanol by hydrogenating carbon dioxide and a preparation method thereof. Background Art

[0002] Carbon dioxide is not only the primary greenhouse gas contributing to global warming, but it is also an inexpensive, clean, and abundant natural resource. To fully utilize this resource and promote the development of the chemical industry and a sustainable energy economy, biomass methanol technology utilizes renewable biomass resources to produce green methanol through synthesis gas obtained through biomass gasification. This technology offers advantages such as low carbon emissions throughout its lifecycle, relatively low production costs, and ease of obtaining EU green methanol certification, attracting widespread attention within the industry.

[0003] High-efficiency catalysts are the key to CO2 hydrogenation to methanol technology. Currently, the most widely used methanol synthesis catalyst in industrial applications is the Cu-Zn-Al system. In the CO2 hydrogenation to methanol reaction, CO2 is stable and difficult to activate, resulting in a low CO2 conversion rate of traditional catalysts. At the same time, the H2O produced during the reaction will cause the active component Cu 0 Therefore, how to improve the CO2 activation ability of the catalyst while inhibiting the active component Cu 0 The sintering deactivation of Cu-based catalysts is crucial to the study of Cu-based catalysts. Summary of the Invention

[0004] The present invention provides a copper-based catalyst for synthesizing methanol by hydrogenating carbon dioxide and a preparation method thereof. The catalyst can improve the activation ability of CO2 and inhibit the sintering deactivation of Cu.

[0005] The present invention provides a method for preparing a copper-based catalyst for synthesizing methanol by hydrogenating carbon dioxide, the method comprising: Providing a carrier mixed solution, the carrier mixed solution comprising a soluble iron salt and an aluminum salt; providing a precipitant solution comprising sodium carbonate and sodium hydroxide; Providing an active metal mixed solution, the active metal mixed solution comprising a soluble copper salt, a soluble zinc salt and a soluble metal additive salt; mixing the carrier mixed solution with the precipitant solution to obtain a precipitation slurry; The precipitated slurry is aged, and then washed, dried and calcined in sequence to obtain a carrier; mixing the support with the active metal mixed solution, and drying and calcining the mixture; Among them, the molar ratio of Cu, Zn, Fe, Al and metal additives is 20-50%: 10-30%: 10-25%: 10-25%: 0-10%.

[0006] Furthermore, the concentration of the carrier mixed solution is 0.1-2 mol / L.

[0007] Furthermore, the concentration of the precipitant solution is 0.1-2 mol / L.

[0008] Furthermore, the concentration of the active metal mixed solution is 0.1-2 mol / L.

[0009] Furthermore, in the carrier mixed solution, the molar ratio of Fe to Al is 0.4-2.5:1.

[0010] Furthermore, in the active metal mixed solution, the molar ratio of Cu to Zn is 0.66-5:1 Furthermore, the molar ratio of sodium carbonate to sodium hydroxide is 1-3:1.

[0011] Furthermore, the metal additive includes one or more of Zr, Mg, La, Ce, Mn, and Ti.

[0012] Furthermore, when the carrier mixed solution is mixed with the precipitant solution, the method includes: Establish the liquid level in the reactor and control the temperature within the set temperature range; Under the condition of continuous stirring, the carrier mixed solution and the precipitant solution are simultaneously added dropwise into the reactor; The pH of the system was maintained at the set value by adjusting the dropwise addition rate of the precipitant solution.

[0013] Furthermore, when the support is mixed with the active metal mixed solution, the method includes: grinding the carrier to form it into a powder; At a set temperature, the active metal mixed solution and the carrier are mixed and stirred.

[0014] The present invention also provides a copper-based catalyst for synthesizing methanol by hydrogenating carbon dioxide. The copper-based catalyst for synthesizing methanol by hydrogenating carbon dioxide is prepared by the above-mentioned method for preparing the copper-based catalyst for synthesizing methanol by hydrogenating carbon dioxide. The catalyst includes a carrier and a load. The carrier is Fe2O3 / Al2O3 with a porous structure. The load is CuO, ZnO and a metal additive. The mass ratio of Cu, Zn, Fe, Al and the metal additive is: 20-50%: 10-30%: 10-25%: 10-25%: 0%-10%, wherein the metal additive is one or more of Mg, La, Ce, Mn and Ti.

[0015] In summary, in the present invention, a mixed solution of Fe and Al mixed nitrates is first subjected to a co-precipitation method to obtain a mixed carrier; then the active metals Cu, Zn, and additives are loaded into the carrier by an impregnation method. This can better form a pore structure on the carrier and better introduce the load into the carrier. After the first mixed metal solution containing iron and aluminum elements is mixed and calcined with a precipitant solution containing sodium carbonate and sodium hydroxide, Fe2O3 can be introduced into the carrier, and the resulting composite carrier Al2O3 / Fe2O3 improves the pore structure of the catalyst, increases the specific surface area of the catalyst, and expands the pore volume and pore size, which allows the catalyst to accelerate the overflow of water vapor while improving the dispersion of active metals and inhibiting Cu 0 The sintering of Cu-Fe2O3 increases the stability of the catalyst. Furthermore, during the reduction process, a large number of oxygen vacancies are generated on the catalyst surface due to the reduction of Fe2O3. The oxygen vacancies on the catalyst surface are conducive to the adsorption and activation of CO2, thereby improving the CO2 activation ability of the catalyst. Furthermore, there is a dynamic interaction between Cu and Fe2O3. Cu particles promote the reduction of Fe2O3 to Fe 2+ , the Fe 2+ The substance in turn promotes H2 in Cu 0 Surface activation, and the activation and dissociation of H2 is the rate-controlling step in the synthesis of methanol from CO2, thereby greatly improving the reaction efficiency of the catalyst and achieving efficient methanol synthesis reaction.

[0016] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the following preferred embodiments are specifically cited and described in detail as follows. DETAILED DESCRIPTION

[0017] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the present invention is described in detail below in conjunction with preferred embodiments.

[0018] The present invention provides a copper-based catalyst for synthesizing methanol by hydrogenating carbon dioxide and a preparation method thereof. The catalyst can improve the activation ability of CO2 and inhibit the sintering deactivation of Cu.

[0019] The preparation method of the copper-based catalyst for synthesizing methanol by hydrogenation of carbon dioxide provided by the present invention comprises the following steps: A carrier mixed solution is provided, wherein the carrier mixed solution includes a soluble iron salt and an aluminum salt.

[0020] In this embodiment, the soluble iron salt and aluminum salt in the carrier mixed solution may be ferric nitrate and aluminum nitrate. The concentration of the carrier mixed solution may be 0.1-2 mol / L (i.e., the total concentration of the iron salt and aluminum salt in the solution), and further, it may be 0.2 mol / L, 0.4 mol / L, 0.6 mol / L, 1.0 mol / L, 1.2 mol / L, 1.5 mol / L, 1.7 mol / L, 1.9 mol / L, etc.

[0021] The molar ratio of Fe to Al is 0.4-2.5: 1. Furthermore, it can be 0.5: 1, 0.8: 1, 1: 1, 1.5: 1, 2: 1, 2.2: 1, etc.

[0022] The above solution can be obtained by dissolving soluble iron salt and aluminum salt in deionized water.

[0023] A precipitant solution is provided, which may be a mixed solution of sodium carbonate and sodium hydroxide.

[0024] In this embodiment, the concentration of the precipitant solution is 0.1-2 mol / L (i.e., the total concentration of sodium carbonate and sodium hydroxide). Further, it can be: 0.2 mol / L, 0.4 mol / L, 0.6 mol / L, 1.0 mol / L, 1.2 mol / L, 1.5 mol / L, 1.7 mol / L, 1.9 mol / L, etc.

[0025] The molar ratio of sodium carbonate to sodium hydroxide can be 1-3:1.

[0026] The above-mentioned precipitant solution can be obtained by dissolving sodium carbonate and sodium hydroxide in deionized water.

[0027] An active metal mixed solution is provided. The active metal mixed solution may include a soluble copper salt, a soluble zinc salt and a soluble metal promoter salt.

[0028] In this embodiment, the soluble copper salt and the soluble zinc salt may be copper nitrate and zinc nitrate. The concentration of the active metal mixed solution may be 0.1-2 mol / L (i.e., the total concentration of the copper salt, zinc salt, and auxiliary metal salt in the solution), and further, it may be 0.2 mol / L, 0.4 mol / L, 0.6 mol / L, 1.0 mol / L, 1.2 mol / L, 1.5 mol / L, 1.7 mol / L, 1.9 mol / L, etc.

[0029] Furthermore, in the active metal mixed solution, the molar ratio of Cu to Zn is 0.66-5: 1. Furthermore, it can be 0.7:1, 0.8:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, etc.

[0030] The carrier mixed solution is mixed with the precipitant solution to form a precipitation slurry.

[0031] In this step, a certain liquid level can be first established in the reactor, and the temperature can be controlled within the range of 20-90°C. Under continuous stirring, the carrier mixed solution and the precipitant solution are simultaneously added dropwise into the reactor. The dropping rate of the precipitant solution is adjusted so that the pH of the system is 6-9 to form a precipitation slurry.

[0032] The precipitated slurry is aged, and then washed, dried and calcined in sequence to obtain a carrier.

[0033] In this embodiment, the aging temperature can be 1-6 hours to allow the mixed solution of the carrier mixed solution and the precipitant to be fully precipitated. During drying, the drying temperature is 50-120°C, and during calcination, the calcination temperature is 350-550°C, and the calcination time is 2-6 hours.

[0034] The carrier is mixed with an active metal mixed solution, and then the mixture is dried and calcined to obtain a copper-based catalyst for synthesizing methanol by hydrogenating carbon dioxide.

[0035] In this embodiment, the carrier may be fully ground to form a powder first, and then the active metal mixed solution and the carrier may be mixed and stirred at a temperature of 20-80° C. to fully mix them.

[0036] After mixing, the mixture is dried at a temperature of 50-120°C and calcined at a temperature of 350-550°C.

[0037] Furthermore, in the obtained catalyst, the molar ratio of Cu, Zn, Fe, Al and metal additive is: 20-50%: 10-30%: 10-25%: 10-25: 0%-10%; the metal additive includes one or more of Zr, Mg, La, Ce, Mn and Ti.

[0038] In this embodiment, a mixed solution of Fe and Al mixed nitrates is first subjected to a co-precipitation method to obtain a mixed carrier; then the active metals Cu, Zn, and additives are loaded into the carrier by an impregnation method. This can better form a pore structure on the carrier and better introduce the load into the carrier. After the first mixed metal solution containing iron and aluminum elements is mixed and calcined with a precipitant solution containing sodium carbonate and sodium hydroxide, Fe2O3 can be introduced into the carrier, and the resulting composite carrier Al2O3 / Fe2O3 improves the pore structure of the catalyst, increases the specific surface area of the catalyst, and expands the pore volume and pore size. This allows the catalyst to accelerate the overflow of water vapor while improving the dispersion of active metals, thereby inhibiting the Cu 0 The sintering of Cu-Fe2O3 increases the stability of the catalyst. Furthermore, during the reduction process, a large number of oxygen vacancies are generated on the catalyst surface due to the reduction of Fe2O3. The oxygen vacancies on the catalyst surface are conducive to the adsorption and activation of CO2, thereby improving the CO2 activation ability of the catalyst. Furthermore, there is a dynamic interaction between Cu and Fe2O3. Cu particles promote the reduction of Fe2O3 to Fe 2+ , the Fe 2+ The substance in turn promotes H2 in Cu 0 Surface activation, and the activation and dissociation of H2 is the rate-controlling step in the synthesis of methanol from CO2, thereby greatly improving the reaction efficiency of the catalyst and achieving efficient methanol synthesis reaction.

[0039] The above preparation method is further described below with reference to specific embodiments.

[0040] Example 1 (Cu:Zn:Fe:Al molar ratio = 50:15:10:25) 1) Dissolve 4.84 g of ferric nitrate nonahydrate and 11.25 g of aluminum nitrate nonahydrate in deionized water to prepare a carrier mixed solution with a concentration of 0.5 mol / L. Dissolve 12.24 g of sodium carbonate and 2.4 g of sodium hydroxide in deionized water to prepare a precipitant solution with a concentration of 0.5 mol / L. Dissolve 14.46 g of copper nitrate trihydrate and 5.34 g of zinc nitrate hexahydrate in deionized water to prepare an active metal mixed solution with a concentration of 0.5 mol / L; 2) Establish a certain liquid level in the reactor, control the precipitation temperature at 70°C, and use a peristaltic pump to simultaneously add the carrier mixed solution and the precipitant solution to the reactor under continuous stirring. Adjust the precipitant addition rate to keep the pH of the system at 7 to form a precipitate slurry. 3) After the carrier metal solution is precipitated, it is aged at 70°C for 2 hours. The slurry is then filtered and washed, and dried at 100°C for 12 hours. After the sample is dried, it is calcined at 500°C for 2 hours in a muffle furnace to obtain a mixed carrier Fe2O3 / Al2O3.

[0041] 4) The prepared carrier Fe2O3 / Al2O3 was fully ground and stirred with the active metal mixed solution at room temperature for 12 hours. After stirring, it was placed in a 100°C oven to dry for 8 hours, and then calcined in a muffle furnace at 350°C for 4 hours to prepare the desired catalyst.

[0042] Example 2 (Cu:Zn:Fe:Al:Mg molar ratio = 50:15:10:15:10) 1) Dissolve 4.84 g of ferric nitrate nonahydrate and 6.75 g of aluminum nitrate nonahydrate in deionized water to prepare a carrier mixed solution with a concentration of 0.5 mol / L. Dissolve 12.24 g of sodium carbonate and 2.4 g of sodium hydroxide in deionized water to prepare a precipitant solution with a concentration of 0.5 mol / L. 14.46 g of copper nitrate trihydrate, 5.34 g of zinc nitrate hexahydrate, and 3.07 g of magnesium nitrate hexahydrate were dissolved in deionized water to prepare an active metal mixed solution with a concentration of 0.5 mol / L; 2) Establish a certain liquid level in the reactor, control the precipitation temperature at 70°C, and use a peristaltic pump to simultaneously add the carrier mixed solution and the precipitant solution to the reactor under continuous stirring. Adjust the precipitant addition rate to keep the pH of the system at 7 to form a precipitate slurry. 3) After the carrier metal solution is precipitated, it is aged at 70°C for 2 hours. The slurry is then filtered and washed, and dried at 100°C for 12 hours. After the sample is dried, it is calcined at 500°C for 2 hours in a muffle furnace to obtain a mixed carrier Fe2O3 / Al2O3.

[0043] 4) The prepared carrier Fe2O3 / Al2O3 was fully ground and stirred with the active metal mixed solution at room temperature for 12 hours. After stirring, it was placed in a 100°C oven to dry for 8 hours, and then calcined in a muffle furnace at 350°C for 4 hours to prepare the desired catalyst.

[0044] Example 3 (Cu:Zn:Fe:Al:Ce molar ratio = 45:15:10:20:10) 1) Dissolve 9.69 g of ferric nitrate nonahydrate and 18 g of aluminum nitrate nonahydrate in deionized water to prepare a carrier mixed solution with a concentration of 1 mol / L. Dissolve 24.48 g of sodium carbonate and 4.8 g of sodium hydroxide in deionized water to prepare a precipitant solution with a concentration of 1 mol / L. 25.97 g of copper nitrate trihydrate, 10.68 g of zinc nitrate hexahydrate, and 10.4 g of cerium nitrate hexahydrate were dissolved in deionized water to prepare an active metal mixed solution with a concentration of 1 mol / L; 2) Establish a certain liquid level in the reactor, control the precipitation temperature at 80°C, and use a peristaltic pump to simultaneously add the carrier mixed solution and the first precipitant solution to the reactor under continuous stirring. Adjust the precipitant addition rate to keep the pH of the system at 7.5 to form a precipitate slurry; 3) After the carrier metal solution is precipitated, it is aged at 70°C for 2 hours, then the slurry is filtered and washed, and dried at 70°C for 12 hours. After the sample is dried, it is calcined at 500°C for 2 hours in a muffle furnace to obtain a mixed carrier Fe2O3 / Al2O3 4) The prepared carrier Fe2O3 / Al2O3 was fully ground and stirred with the active metal mixed solution at room temperature for 12 hours. After stirring, it was placed in an 80°C oven to dry for 8 hours, and then calcined in a muffle furnace at 350°C for 4 hours to prepare the desired catalyst.

[0045] Example 4 (Cu:Zn:Fe:Al:Mg:Ce molar ratio = 45:15:10:20:5:5) 1) Dissolve 9.69 g of ferric nitrate nonahydrate and 18 g of aluminum nitrate nonahydrate in deionized water to prepare a carrier mixed solution with a concentration of 1 mol / L. Dissolve 24.48 g of sodium carbonate and 4.8 g of sodium hydroxide in deionized water to prepare a precipitant solution with a concentration of 1 mol / L.

[0046] 25.97 g of copper nitrate trihydrate, 10.68 g of zinc nitrate hexahydrate, 4.1 g of magnesium nitrate hexahydrate, and 5.2 g of cerium nitrate hexahydrate were dissolved in deionized water to prepare an active metal mixed solution with a concentration of 1 mol / L.

[0047] 2) Establish a certain liquid level in the reactor, control the precipitation temperature at 80°C, and use a peristaltic pump to simultaneously add the carrier mixed solution and the first precipitant solution to the reactor under continuous stirring. Adjust the precipitant addition rate to keep the pH of the system at 7.5 to form a precipitate slurry; 3) After the carrier metal solution is precipitated, it is aged at 70°C for 2 hours, then the slurry is filtered and washed, and dried at 70°C for 12 hours. After the sample is dried, it is calcined at 500°C for 2 hours in a muffle furnace to obtain a mixed carrier Fe2O3 / Al2O3 4) The prepared carrier Fe2O3 / Al2O3 was fully ground and stirred with the active metal mixed solution at room temperature for 12 hours. After stirring, it was placed in a 60°C oven to dry for 8 hours, and then calcined in a muffle furnace at 350°C for 4 hours to prepare the desired catalyst.

[0048] Example 5 (Cu:Zn:Fe:Al:La molar ratio = 45:20:15:10:10) 1) Dissolve 29.07 g of ferric nitrate nonahydrate and 18 g of aluminum nitrate nonahydrate in deionized water to prepare a carrier mixed solution with a concentration of 1.5 mol / L. Dissolve 48.96 g of sodium carbonate and 9.6 g of sodium hydroxide in deionized water to prepare a precipitant solution with a concentration of 1.5 mol / L.

[0049] 52.05 g of copper nitrate trihydrate, 28.5 g of zinc nitrate hexahydrate, and 20.78 g of lanthanum nitrate hexahydrate were dissolved in deionized water to prepare an active metal mixed solution with a concentration of 1.5 mol / L; 2) Establish a certain liquid level in the reactor, control the precipitation temperature at 80°C, and use a peristaltic pump to simultaneously add the carrier mixed solution and the first precipitant solution to the reactor under continuous stirring. Adjust the precipitant addition rate to keep the system pH at 8 to form a precipitate slurry. 3) After the carrier metal solution is precipitated, it is aged at 80°C for 2 hours, then the slurry is filtered and washed, and dried at 80°C for 12 hours. After the sample is dried, it is calcined at 500°C for 2 hours in a muffle furnace to obtain a mixed carrier Fe2O3 / Al2O3 4) The prepared carrier Fe2O3 / Al2O3 was fully ground and stirred with the active metal mixed solution at room temperature for 12 hours. After stirring, it was placed in an 80°C oven to dry for 8 hours, and then calcined in a muffle furnace at 350°C for 4 hours to prepare the desired catalyst.

[0050] Example 6 (Cu:Zn:Fe:Al:Mg:La:Ce molar ratio = 50:10:15:10:5:5:5) 1) Dissolve 19.38 g of ferric nitrate nonahydrate and 18 g of aluminum nitrate nonahydrate in deionized water to prepare a carrier mixed solution with a concentration of 1.5 mol / L. Dissolve 48.96 g of sodium carbonate and 9.6 g of sodium hydroxide in deionized water to prepare a precipitant solution with a concentration of 1.5 mol / L.

[0051] 57.83 g of copper nitrate trihydrate, 14.3 g of zinc nitrate hexahydrate, 6.15 g of magnesium nitrate hexahydrate, 10.39 g of lanthanum nitrate hexahydrate, and 7.8 g of cerium nitrate hexahydrate were dissolved in deionized water to prepare an active metal mixed solution with a concentration of 1.5 mol / L; 2) Establish a certain liquid level in the reactor, control the precipitation temperature at 70°C, and use a peristaltic pump to simultaneously add the carrier mixed solution and the first precipitant solution to the reactor under continuous stirring. Adjust the precipitant addition rate to keep the pH of the system at 7.5 to form a precipitate slurry. 3) After the carrier metal solution is precipitated, it is aged at 70°C for 2 hours, then the slurry is filtered and washed, and dried at 70°C for 12 hours. After the sample is dried, it is calcined at 500°C for 2 hours in a muffle furnace to obtain a mixed carrier Fe2O3 / Al2O3 4) The prepared carrier Fe2O3 / Al2O3 was fully ground and stirred with the active metal mixed solution at room temperature for 12 hours. After stirring, it was placed in a 70°C oven to dry for 8 hours, and then calcined in a muffle furnace at 350°C for 4 hours to prepare the desired catalyst.

[0052] Comparative Example 1 (Cu:Zn:Al molar ratio = 50:15:35) 1) Dissolve 23.62g of aluminum nitrate nonahydrate in deionized water to prepare a carrier mixed solution with a concentration of 0.5 mol / L. Dissolve 12.24g of sodium carbonate and 2.4g of sodium hydroxide in deionized water to prepare a precipitant solution with a concentration of 0.5 mol / L. Dissolve 14.46 g of copper nitrate trihydrate and 5.34 g of zinc nitrate hexahydrate in deionized water to prepare an active metal mixed solution with a concentration of 0.5 mol / L; 2) Establish a certain liquid level in the reactor, control the precipitation temperature at 70°C, and use a peristaltic pump to simultaneously add the carrier mixed solution and the precipitant solution to the reactor under continuous stirring. Adjust the precipitant addition rate to keep the pH of the system at 7 to form a precipitate slurry. 3) After the carrier metal solution is precipitated, it is aged at 70°C for 2 hours, then the slurry is filtered and washed, and dried at 100°C for 12 hours. After the sample is dried, it is calcined at 500°C for 2 hours in a muffle furnace to obtain a mixed carrier.

[0053] 4) The prepared carrier Fe2O3 / Al2O3 was fully ground and stirred with the active metal mixed solution at room temperature for 12 hours. After stirring, it was placed in a 100°C oven to dry for 8 hours, and then calcined in a muffle furnace at 350°C for 4 hours to prepare the desired catalyst.

[0054] Comparative Example 2 (Cu:Zn:Fe:Al molar ratio = 50:15:10:25) 1) Dissolve 4.84 g of ferric nitrate nonahydrate and 11.25 g of aluminum nitrate nonahydrate in deionized water to prepare a carrier metal solution with a concentration of 0.5 mol / L. Dissolve 12.24 g of sodium carbonate and 2.4 g of sodium hydroxide in deionized water to prepare a precipitant solution with a concentration of 0.5 mol / L. Dissolve 14.46 g of copper nitrate trihydrate and 5.34 g of zinc nitrate hexahydrate in deionized water to prepare an active metal mixed solution with a concentration of 0.5 mol / L; 2) Establish a certain liquid level in the reactor, control the precipitation temperature at 70°C, and use a metering pump to simultaneously add the carrier mixed solution and a portion of the precipitant solution to the reactor under continuous stirring. Adjust the precipitant addition rate to keep the system pH at 7 to form a precipitate slurry; 3) After the carrier metal solution is precipitated, age it at 70°C for 2 hours. After the slurry is stirred evenly, the active metal mixed solution and another part of the precipitant solution are added dropwise to the carrier precipitation slurry at 70°C using a peristaltic pump. The precipitant addition rate is controlled to maintain the pH of the system at around 7.

[0055] 4) After the second active metal mixed solution is added, the addition of the precipitant solution is stopped, stirring is discontinued, and aging is maintained at the precipitation temperature for 4 hours. The aged catalyst precursor slurry is then filtered and washed, dried at 100°C for 8 hours, and calcined in a muffle furnace at 350°C for 4 hours to obtain Reference Catalyst 2.

[0056] Table 1 Performance of catalysts for CO2 hydrogenation to methanol under different preparation conditions Reaction conditions: 230°C, GHSV = 10000 ml.gcat -1 . h -1 、5MPa、H2:CO2:N2=23:69:8

[0057] As can be seen from the table above, compared to reference catalyst 1-2, catalyst 1-6 significantly improves carbon dioxide conversion, methanol selectivity, and methanol space-time yield. Furthermore, its decay rate after 50 hours of reaction is significantly reduced.

[0058] The present invention also provides a copper-based catalyst for synthesizing methanol from carbon dioxide hydrogenation, prepared according to the above-mentioned method for preparing a copper-based catalyst for synthesizing methanol from carbon dioxide hydrogenation. The catalyst comprises a carrier and a support. The carrier is Fe2O3 / Al2O3 having a porous structure, and the support comprises CuO, ZnO, and a metal additive. The mass ratio of Cu, Zn, Fe, Al, and the metal additive is 20-50%: 10-30%: 10-25%: 10-25%: 0%-10%. The metal additive is one or more of Mg, La, Ce, Mn, and Ti.

[0059] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make slight changes or modifications to equivalent embodiments using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a copper-based catalyst for synthesizing methanol by hydrogenation of carbon dioxide, characterized in that: The method includes: Providing a carrier mixed solution, the carrier mixed solution comprising a soluble iron salt and an aluminum salt; providing a precipitant solution comprising sodium carbonate and sodium hydroxide; Providing an active metal mixed solution, the active metal mixed solution comprising a soluble copper salt, a soluble zinc salt and a soluble metal additive salt; mixing the carrier mixed solution with the precipitant solution to obtain a precipitation slurry; The precipitated slurry is aged, and then washed, dried and calcined in sequence to obtain a carrier; mixing the support and the active metal mixed solution to obtain a mixture, and drying and calcining the mixture; The molar ratio of Cu, Zn, Fe, Al and metal additives is 20-50%: 10-30%: 10-25%: 10-25%: 0-10%.

2. The method for preparing a copper-based catalyst for synthesizing methanol from carbon dioxide hydrogenation according to claim 1, characterized in that: The method comprises at least one of the following: the concentration of the carrier mixed solution is 0.1-2 mol / L, the concentration of the precipitant solution is 0.1-2 mol / L, and the concentration of the active metal mixed solution is 0.1-2 mol / L.

3. The method for preparing a copper-based catalyst for synthesizing methanol from carbon dioxide hydrogenation according to claim 1, characterized in that: In the carrier mixed solution, the molar ratio of Fe to Al is 0.4-2.5:

1.

4. The method for preparing a copper-based catalyst for synthesizing methanol from carbon dioxide hydrogenation according to claim 1, wherein: In the active metal mixed solution, the molar ratio of Cu to Zn is 0.66-5:

1.

5. The method for preparing a copper-based catalyst for synthesizing methanol from carbon dioxide hydrogenation according to claim 1, characterized in that: The molar ratio of sodium carbonate to sodium hydroxide is 1-3:

1.

6. The method for preparing a copper-based catalyst for synthesizing methanol from carbon dioxide hydrogenation according to claim 1, characterized in that: The metal additive includes one or more of Zr, Mg, La, Ce, Mn, and Ti.

7. The method for preparing a copper-based catalyst for synthesizing methanol from carbon dioxide hydrogenation according to claim 1, characterized in that: When the carrier mixed solution is mixed with the precipitant solution, the method comprises: Establish the liquid level in the reactor and control the temperature within the set temperature range; Under the condition of continuous stirring, the carrier mixed solution and the precipitant solution are simultaneously added dropwise into the reactor; The pH of the system was maintained at the set value by adjusting the dropwise addition rate of the precipitant solution.

8. The method for preparing a copper-based catalyst for synthesizing methanol from carbon dioxide hydrogenation according to claim 1, characterized in that: When the support is mixed with the active metal mixed solution, the method comprises: grinding the carrier to form it into a powder; At a set temperature, the active metal mixed solution and the carrier are mixed and stirred.

9. A copper-based catalyst for synthesizing methanol by hydrogenation of carbon dioxide, characterized by: The copper-based catalyst for synthesizing methanol by hydrogenation of carbon dioxide is prepared by the preparation method of the copper-based catalyst for synthesizing methanol by hydrogenation of carbon dioxide according to any one of claims 1 to 9, the catalyst comprising a carrier and a load, the carrier being Fe2O3 / Al2O3 having a porous structure, the load being CuO, ZnO and a metal additive, and the mass ratio of Cu, Zn, Fe, Al and the metal additive being 20-50%: 10-30%: 10-25%: 10-25%: 0%-10% by mass, wherein the metal additive is one or more of Mg, La, Ce, Mn and Ti.

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