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CN-121972170-A - Copper-zinc-aluminum-based catalyst with core-shell structure and preparation method and application thereof

CN121972170ACN 121972170 ACN121972170 ACN 121972170ACN-121972170-A

Abstract

The invention belongs to the technical field of catalysts, and relates to a copper-zinc-aluminum-based catalyst with a core-shell structure, and a preparation method and application thereof. The catalyst comprises a core-shell structure and an auxiliary agent dispersed on the surface of the core-shell, wherein the core-shell structure comprises an inner core of Cu-Zn-Al active components and an outer shell coated on the surface of the inner core, the outer shell is a composite oxide coating of ZrO 2 and SiO 2 , the mass of the inner core is 60-80% of the total amount of the catalyst, the thickness of the outer shell is 50-200 nm, the auxiliary agent is CeO 2 , and the mass of the auxiliary agent is 1-5% of the total amount of the catalyst. According to the invention, through the coordination of core-shell structure design and additive modification, the high activity, high stability and long service life of the catalyst under the temperature fluctuation working condition are realized, the continuity of controllable atmosphere preparation is ensured, and the industrial operation cost is reduced.

Inventors

  • WANG JIANMEI
  • CAI FEIPENG
  • SI HONGYU
  • FANG HENGYI
  • WANG LUYUAN
  • WANG SHUYUAN
  • CHEN CHENGMIN
  • KANG RONGKAI

Assignees

  • 山东省科学院能源研究所

Dates

Publication Date
20260505
Application Date
20260115

Claims (10)

  1. 1. The catalyst based on the copper-zinc-aluminum core-shell structure is characterized by comprising a core-shell structure and an auxiliary agent dispersed on the surface of the core-shell structure, wherein the core-shell structure comprises an inner core of Cu-Zn-Al active components and an outer shell coated on the surface of the inner core, the outer shell is a composite oxide coating of ZrO 2 and SiO 2 , the mass of the inner core is 60-80% of the total amount of the catalyst, the thickness of the outer shell is 50-200 nm, the auxiliary agent is CeO 2 , and the mass of the auxiliary agent is 1-5% of the total amount of the catalyst.
  2. 2. The catalyst according to claim 1, wherein the molar ratio of elements Cu, zn and Al in the Cu-Zn-Al active ingredient is (4-6): 2-3): 1-2.
  3. 3. The catalyst of claim 1, wherein the molar ratio of ZrO 2 to SiO 2 in the composite oxide coating of ZrO 2 to SiO 2 is (3-5): 1-2.
  4. 4. A method for preparing the catalyst according to any one of claims 1 to 3, comprising the steps of: Dissolving copper salt, zinc salt and aluminum salt in water to prepare a mixed solution, adding ammonia water or alkali metal hydroxide into the mixed solution to prepare hydroxide precipitate, washing, drying, and roasting for one time to prepare a Cu-Zn-Al oxide precursor; Dissolving a precursor of zirconium oxide and a precursor of silicon oxide in a solvent, hydrolyzing to form sol, adding a precursor of Cu-Zn-Al oxide into the sol for impregnation to enable the surface of the precursor of Cu-Zn-Al oxide to adsorb the sol, and then drying and secondary roasting to enable the sol to be converted into a composite oxide coating of ZrO2 and SiO2 so as to form a core-shell structure; And adding the core-shell structure into cerium salt solution, carrying out ultrasonic impregnation, and then drying and three-time roasting the impregnated core-shell structure to convert cerium salt impregnated in the core-shell structure into cerium oxide.
  5. 5. The method according to claim 4, wherein the pH is 7.0 to 8.0, the temperature is 60 to 80 ℃ and the time is 2 to 4 hours during the preparation of the hydroxide precipitate.
  6. 6. The method according to claim 4, wherein zirconium oxychloride and ethyl orthosilicate are added into an ethanol aqueous solution to be dissolved, an acid is added to adjust the pH to 3-4, and hydrolysis is performed to form ZrO 2 -SiO 2 sol.
  7. 7. The method according to claim 4, wherein the Cu-Zn-Al oxide precursor is added to the sol and impregnated at a temperature of 50-70 ℃ for 4-6 hours.
  8. 8. The method of claim 4, wherein the ultrasonic immersion time is 1 to 2 hours.
  9. 9. The method according to claim 4, wherein the temperature of the primary baking is 400-550 ℃; Or, the temperature of the secondary roasting is 500-600 ℃; or, the temperature of the three times of roasting is 400-500 ℃.
  10. 10. Use of the catalyst of any one of claims 1-3 in catalytic methanol cracking gas production or catalytic ammonia-methanol coupling gas production.

Description

Copper-zinc-aluminum-based catalyst with core-shell structure and preparation method and application thereof Technical Field The invention belongs to the technical field of catalysts, and relates to a copper-zinc-aluminum-based catalyst with a core-shell structure, and a preparation method and application thereof. Background The disclosure of this background section is only intended to increase the understanding of the general background of the invention and is not necessarily to be construed as an admission or any form of suggestion that this information forms the prior art already known to those of ordinary skill in the art. In the industrial fields of high-carbon steel heat treatment and the like, the stable preparation of the controllable atmosphere is a key for guaranteeing the quality of products, and the ammonia-methanol coupling gas preparation process has become one of the main stream technologies for preparing the controllable atmosphere in the field due to the advantages of easily available raw materials, controllable gas preparation components and the like. The core of the process is in the methanol cracking reaction, and the Cu-Zn-Al-based catalyst is widely applied to the reaction system by virtue of the characteristics of high catalytic activity, low cost and the like of the methanol cracking reaction. However, in the actual industrial production process, the cracking reaction temperature of the ammonia-methanol coupling gas production process is susceptible to various factors such as raw material supply stability, heat dissipation efficiency of a reaction device, adjustment of working condition load and the like, and a large-scale temperature fluctuation is unavoidable. Under the frequent and large-amplitude temperature fluctuation (more than or equal to +/-50 ℃) working condition of the traditional Cu-Zn-Al catalyst, active component Cu particles of the catalyst are easy to migrate, agglomerate and sinter, a carrier pore structure collapses and is carbon deposited, the number of active sites of Cu and the specific surface area of the catalyst are reduced, and the catalytic activity is rapidly attenuated, so that the service life of the catalyst is generally shorter, and the catalyst can be generally maintained for only hundreds of hours. The frequent deactivation and replacement of the catalyst not only increases the operation cost of the ammonia-methanol coupling gas production process, but also causes unstable gas production efficiency and fluctuation of controllable atmosphere components so as to influence the product qualification rate of high-carbon steel heat treatment, and meanwhile, the frequent shutdown and replacement of the catalyst can reduce the production continuity, thereby further restricting the high-efficiency application of the ammonia-methanol coupling gas production process in the industrial field. Therefore, developing an ammonia-methanol coupled gas-making catalyst system which has excellent heat fluctuation resistance and long service life and can maintain high cracking efficiency under the temperature fluctuation working condition has become a technical problem to be solved in the field. Disclosure of Invention In order to solve the defects of the prior art, the invention aims to provide a catalyst with a core-shell structure based on copper-zinc-aluminum and a preparation method and application thereof, the invention is cooperated with auxiliary agent modification through core-shell structure design, the high activity, high stability and long service life of the catalyst under the temperature fluctuation working condition are realized, the continuity of controllable atmosphere preparation is ensured, and the industrial operation cost is reduced. In order to achieve the above purpose, the invention adopts the following technical scheme: In a first aspect, the catalyst based on the copper-zinc-aluminum core-shell structure comprises a core-shell structure and an auxiliary agent dispersed on the surface of the core-shell structure, wherein the core-shell structure comprises an inner core of Cu-Zn-Al active components and an outer shell coated on the surface of the inner core, the outer shell is a composite oxide coating of ZrO 2 and SiO 2, the mass of the inner core is 60-80% of the total amount of the catalyst, the thickness of the outer shell is 50-200 nm, the auxiliary agent is CeO 2, and the mass of the auxiliary agent is 1-5% of the total amount of the catalyst. The invention takes Cu-Zn-Al active components as the inner core, wherein Cu is taken as a main active element, can efficiently catalyze the breakage of a methanol C-H bond, znO is taken as a structure auxiliary agent, can inhibit the aggregation of Cu particles, and Al 2O3 is taken as a carrier framework, so that the structural stability of the inner core is improved. The composite oxide coating of ZrO 2 and SiO 2 is used as a shell, zrO 2 has excellent thermal stability and thermal conductivity, can buf