A metal composite modified perovskite-type zirconium oxide catalyst and its preparation method and application

Abstract

The present invention provides a metal composite modified perovskite-type zirconium oxide catalyst and its preparation method and application. The preparation method comprises the following steps: (1) mixing a soluble zirconium salt, citric acid and deionized water in a certain proportion to obtain a mixed solution A; (2) adding an alkaline solution dropwise to the mixed solution A to obtain a mixed solution B; (3) placing the mixed solution B in a water bath and stirring at a constant temperature until it becomes a transparent gel, cooling the gel to room temperature, and drying to obtain a precursor C; (4) calcining the precursor C to obtain ZrO2 powder; (5) dissolving the ZrO2 powder in deionized water to obtain a solution, and pouring an appropriate amount of La(NO3)3·6H2O and CrO3 into the above solution, stirring, drying and calcining to obtain the catalyst. The present invention introduces lanthanide metal La and acidic oxide CrO3 to promote lattice distortion of the ZrO2 catalyst, change the oxygen vacancy content in the ZrO2 catalyst, and effectively solve the problems of low CO conversion rate and isobutylene selectivity of the zirconium oxide catalyst in the traditional method.

Description

Technical Field

[0001] The present invention belongs to the technical field of synthesis gas chemical industry and catalyst preparation, and specifically relates to a metal composite modified perovskite-type zirconium oxide catalyst and a preparation method and application thereof. Background Art

[0002] Low-carbon olefins mainly include ethylene, propylene and butene, which are important basic chemical raw materials and are widely used in the fields of synthetic plastics, fibers, rubber, etc. Among them, ethylene can be used in the synthesis of polyethylene, polyvinyl chloride, etc., and propylene is mainly used to prepare acrylonitrile and synthetic rubber. Isobutylene (i-C4 ＝ ) has a wide range of uses. The methyl tert-butyl ether prepared by its reaction with methanol is a good gasoline additive and anti-knock agent. At the same time, high-purity isobutylene can be used as a polymerization monomer or intermediate to prepare fine chemicals such as butyl rubber, polyisobutylene, and methyl methacrylate. However, the traditional method of preparing isobutylene mainly relies on the C4 product of petroleum cracking, which has high separation costs and cannot meet industrial needs. With the expansion of the isobutylene market demand and the contradiction between petroleum resources, exploring clean, efficient, and low-cost isobutylene preparation processes has gradually become a hot topic of increasing attention.

[0003] Synthesis gas, primarily composed of CO and H₂, can be produced from non-petroleum carbon resources such as coal, natural gas, and biomass. Synthesis gas can be highly selectively converted into isobutylene and isobutane over a catalyst in a process known as the isomerization reaction. This route alleviates the dependence of traditional isobutylene production on petroleum resources to a certain extent, establishing a feasible energy development route with a simple process. It is currently believed that the isomerization reaction achieves chain growth through CO insertion and condensation reactions, promoting the formation of branched C₄ products.

[0004] ZrO2 has the properties of high melting point, high hardness, high resistivity, and low thermal expansion coefficient, and is widely used in the glass industry, refractory materials, and inorganic coatings. ZrO2 has a variety of physical phase structures and is rich in oxygen vacancies and acid-base sites. Oxygen vacancies are active sites for the formation of methoxy intermediates between CO and the ZrO2 surface. At the same time, oxygen vacancies and acidic sites jointly promote the condensation reaction in the isomerization reaction, which is beneficial to improving the CO conversion rate. The basic sites in the ZrO2 catalyst can enhance the CO insertion reaction, which is beneficial to improving the selectivity of isobutylene in the product. Therefore, under the joint constraints of oxygen vacancies and acidic and basic sites, ZrO2 catalysts exhibit good catalytic performance in the CO hydroisomerization reaction and are considered to be one of the most promising materials of the 21st century.

[0005] However, the catalytic effect of the zirconium oxide catalyst prepared by the traditional hydrothermal method is poor, and there are problems such as low CO conversion rate and isobutylene selectivity. Based on this, the present application is proposed. Summary of the Invention

[0006] The purpose of the present invention is to overcome the defects of the prior art and provide a metal composite modified perovskite type zirconium oxide catalyst and its preparation method and application, which effectively solves the problems of poor catalytic effect of traditionally prepared zirconium oxide, low CO conversion rate and isobutylene selectivity.

[0007] The present invention provides the following technical solutions:

[0008] The present invention provides a method for preparing a metal composite modified perovskite-type zirconium oxide catalyst, comprising the following steps:

[0009] (1) mixing a soluble zirconium salt, citric acid, and deionized water in a certain proportion to obtain a mixed solution A;

[0010] (2) adding alkali solution dropwise to mixed solution A to obtain mixed solution B;

[0011] (3) Place the mixed solution B in a water bath and stir at a constant temperature until it becomes a transparent gel. After the gel is cooled to room temperature, it is dried to obtain the precursor C;

[0012] (4) calcining the precursor C to obtain ZrO2 powder;

[0013] (5) ZrO2 powder is dissolved in deionized water to obtain a solution, and appropriate amounts of La(NO3)3·6H2O and CrO3 are poured into the above solution and stirred, followed by drying and calcining to obtain a metal composite modified perovskite-type zirconia catalyst.

[0014] Zirconia catalysts prepared by traditional hydrothermal methods contain relatively low oxygen vacancies. Considering the impact of oxygen vacancies on isomerization reactions, the present invention dopes ZrO2 with La and Cr, causing lattice distortion in the catalyst. This improves the lattice energy of the perovskite catalyst and simultaneously activates and migrates lattice oxygen to the crystal surface, increasing the number of oxygen vacancies in the catalyst. Furthermore, the alkaline environment provided by the alkali solution helps improve isobutylene selectivity in the product, but excessive alkalinity is detrimental to CO conversion. The acidic CrO3 reacts with the alkali solution, and the acidic oxide CrO3 undergoes a redox reaction under alkaline conditions, enhancing the catalyst's redox performance. Furthermore, the alkalinity during the preparation process can be appropriately adjusted, which helps improve CO conversion and isobutylene selectivity.

[0015] Furthermore, in step (1), the soluble zirconium salt is any one of zirconium sulfate, zirconium acetate or zirconium nitrate pentahydrate.

[0016] Furthermore, in step (1), the ratio of the soluble zirconium salt, citric acid and deionized water is (8-10) g: (5-10) g: (60-90) mL.

[0017] Furthermore, in step (2), the solute in the alkali solution is any one of sodium hydroxide, potassium hydroxide, and calcium hydroxide.

[0018] Furthermore, in step (2), the ratio of solute to deionized water in the alkali solution is (5-10) g: (20-50) mL.

[0019] Furthermore, in step (2), the ratio of solute to deionized water in the alkali solution is (5-10) g: (20-50) mL.

[0020] Furthermore, in step (3), the stirring temperature of the mixed solution B in a water bath is preferably 80 to 120°C.

[0021] Furthermore, in step (3), the transparent gel-like substance is placed in an oven for drying, the oven temperature is controlled to be 60-100° C., and the drying time is 9-20 hours.

[0022] Furthermore, in step (4), the precursor C is placed in a muffle furnace and calcined at 400-500° C. in an air atmosphere for 3-6 hours. The purpose of calcination is to convert the precursor C into ZrO2, and the ZrO2 powder particle size is 30-80 nm.

[0023] Furthermore, in step (5), the molar ratio of La(NO3)3·6H2O and CrO3 to ZrO2 powder is 1:1:(20-200).

[0024] Furthermore, in step (5), the stirring time is 20-40 min.

[0025] The second object of the present invention is to provide a metal composite modified perovskite-type zirconia catalyst prepared by the above preparation method.

[0026] The third object of the present invention is to provide the use of the metal composite modified perovskite zirconia catalyst prepared above in catalyzing CO hydrogenation isomerization synthesis reaction.

[0027] The preparation method of the metal composite modified perovskite-type zirconium oxide catalyst of the present invention can simultaneously improve the CO conversion rate and the selectivity of isobutylene. The mechanism is as follows:

[0028] ZrO2 interacts with CO to form formate species and methoxy groups, with the sites of methoxy formation believed to be oxygen vacancies. Formate can form methoxy species through hydrogenation. The methoxy groups combine with water to form methanol, which then undergoes chain growth through aldehyde condensation, ultimately forming 2-methylpropanal. 2-Methylpropanal forms isobutylene through hydrogenation or dehydration. However, ZrO2 catalysts undoped with lanthanide metals have a low surface oxygen vacancy content, resulting in a low number of methoxy intermediates and a low CO conversion rate. The metal composite-modified perovskite-type zirconia catalyst of the present invention increases the oxygen vacancy content, forming methoxy intermediates in the isomerization reaction, improving CO conversion and isobutylene selectivity. Furthermore, the added CrO3 is an acidic oxide that can moderately neutralize the alkali solution in the raw material and undergo a reduction reaction to a +4 valence, increasing the oxygen vacancy content. With the enhanced redox properties of the catalyst, CO forms methoxy intermediates with hydroxyl groups on the ZrO2 surface. These intermediates then undergo CO insertion and condensation reactions, further promoting the isomerization reaction.

[0029] The present invention has the following beneficial effects:

[0030] 1. The metal composite-modified perovskite-type zirconia catalyst prepared by the present invention effectively solves the problem of low CO conversion in isomerization synthesis reactions. The introduction of La and Cr elements causes lattice distortion, increases the mobility of lattice oxygen, and the formation of a large number of oxygen vacancies helps improve the redox properties of the catalyst.

[0031] 2. The present invention adds alkaline solution as a precipitant, which is beneficial to improving the yield of the catalyst precursor. At the same time, the alkaline environment created is beneficial to improving the selectivity of isobutylene;

[0032] 3. The metal composite modified perovskite-type zirconia catalyst prepared by the present invention has stable chemical properties, simple process, low cost, and is suitable for industrial production. DETAILED DESCRIPTION

[0033] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] The present invention provides a method for preparing a metal composite modified perovskite-type zirconium oxide catalyst, comprising the following steps:

[0035] (1) mixing a soluble zirconium salt, citric acid, and deionized water in a certain proportion to obtain a mixed solution A;

[0036] (2) adding alkali solution dropwise to mixed solution A to obtain mixed solution B;

[0037] (3) Place the mixed solution B in a water bath and stir at a constant temperature until it becomes a transparent gel. After the gel is cooled to room temperature, it is dried to obtain the precursor C;

[0038] (4) calcining the precursor C to obtain ZrO2 powder;

[0039] (5) ZrO2 powder is dissolved in deionized water to obtain a solution, and appropriate amounts of La(NO3)3·6H2O and CrO3 are poured into the above solution and stirred, followed by drying and calcining to obtain a metal composite modified perovskite-type zirconia catalyst.

[0040] A lanthanide metal La and an acidic metal oxide CrO3 are introduced into the ZrO2 catalyst to form a perovskite catalyst. This catalyst satisfies the traditional perovskite structure formed by the combination of rare earth metals and transition metals, and this structure is conducive to weakening the metal-oxygen bond inside the catalyst. The introduction of the two metals causes the lattice to distort, increases the mobility of lattice oxygen, and is conducive to oxygen loading and storage. The perovskite structure of LaCrZrOz is conducive to electron conduction and provides abundant adsorption sites for CO. At the same time, the added CrO3 is an acidic oxide that can properly neutralize the alkali solution in the raw material and undergo a reduction reaction to become +4 valence, which promotes the increase of oxygen vacancy content. With the improvement of the redox property of the catalyst, CO forms a methoxy intermediate with the hydroxyl group on the surface of ZrO2, and achieves chain growth through CO insertion and condensation reaction, further promoting the progress of the isomerization reaction.

[0041] Zirconia catalysts prepared by traditional hydrothermal methods contain relatively low oxygen vacancies. Considering the impact of oxygen vacancies on isomerization reactions, the present invention dopes ZrO2 with La and Cr, causing lattice distortion in the catalyst. This improves the lattice energy of the perovskite catalyst and simultaneously activates and migrates lattice oxygen to the crystal surface, increasing the number of oxygen vacancies in the catalyst. Furthermore, the alkaline environment provided by the alkali solution helps improve isobutylene selectivity in the product, but excessive alkalinity is detrimental to CO conversion. The acidic CrO3 reacts with the alkali solution, and the acidic oxide CrO3 undergoes a redox reaction under alkaline conditions, enhancing the catalyst's redox performance. Furthermore, the alkalinity during the preparation process can be appropriately adjusted, which helps improve CO conversion and isobutylene selectivity.

[0042] Compared with the ZrO2 catalyst prepared by the traditional hydrothermal method, the catalyst prepared by the sol-gel method of the present invention has a larger specific surface area and the number of active sites, which can improve the CO conversion rate and isobutylene selectivity.

[0043] The present invention will be further described below through specific examples.

[0044] Example 1

[0045] The preparation method of the metal composite modified perovskite-type zirconium oxide catalyst in this example specifically includes the following steps:

[0046] (1) Preparation of soluble nitrate mixed solution A: Weigh 9.22 g of zirconium nitrate pentahydrate (Zr(NO3)4·5H2O) and 6.64 g of citric acid (C6H8O7), dissolve them in 100 mL of deionized water at 600 rad / min, and mechanically stir for 20 min to obtain mixed solution A.

[0047] (2) Prepare mixed solution B: Weigh 3 g of sodium hydroxide (NaOH) and dissolve it in 30 mL of deionized water. Add the prepared alkali solution dropwise into mixed solution A at 400 rad / min until the pH of mixed solution A reaches 10. Continue stirring at 400 rad / min for 30 min to obtain mixed solution B.

[0048] (3) Place the mixed solution B obtained in step (2) in a 100°C water bath and continue stirring at 400 rad / min until it becomes a transparent gel. Place the gel in an 80°C oven and dry for 12 hours to obtain ZrO2 precursor C.

[0049] (4) The precursor obtained in step (3) was placed in a muffle furnace and calcined at 450°C for 4 h in an air atmosphere to obtain white ZrO2 powder.

[0050] (5) The ZrO2 powder obtained in step (4) was stirred and dissolved in 30 mL of deionized water, and La(NO3)3·6H2O and CrO3 powder were added to the solution (the molar ratio of La(NO3)3·6H2O and CrO3 powder to ZrO2 powder was 1:1:20), and the mixture was stirred at 500 rad / min for 30 min to obtain a mixed solution D. The obtained mixed solution D was placed in an oven at 80°C and dried for 12 h, and the dried solid was placed in a muffle furnace and calcined at 450°C in an air atmosphere for 4 h to obtain a product, which was recorded as LaCrZr 20 O z .

[0051] Example 2

[0052] The preparation method of the metal composite modified perovskite zirconia catalyst in this example is basically the same as that in Example 1, except that La(NO3)3·6H2O and CrO3 powder are added in step (5), and the molar ratio of La(NO3)3·6H2O and CrO3 powder to ZrO2 powder is 1:1:50. Therefore, the metal composite modified perovskite zirconia catalyst prepared in this example is marked as LaCrZr 50 O z .

[0053] Example 3

[0054] The preparation method of the metal composite modified perovskite zirconia catalyst in this example is basically the same as that in Example 1, except that La(NO3)3·6H2O and CrO3 powders are added in step (5), and the molar ratio of La(NO3)3·6H2O and CrO3 powders to ZrO2 powder is 1:1:100. Therefore, the metal composite modified perovskite zirconia catalyst prepared in this example is marked as LaCrZr 100 O z .

[0055] Example 4

[0056] The preparation method of the metal composite modified perovskite zirconia catalyst in this example is basically the same as that in Example 1, except that La(NO3)3·6H2O and CrO3 powder are added in step (5), and the molar ratio of La(NO3)3·6H2O and CrO3 powder to ZrO2 powder is 1:1:200. Therefore, the metal composite modified perovskite zirconia catalyst prepared in this example is marked as LaCrZr 200 O z .

[0057] Comparative Example 1

[0058] The method for preparing the zirconium oxide catalyst in this example specifically includes the following steps:

[0059] (1) Preparation of soluble nitrate mixed solution A: Weigh 9.22 g of zirconium nitrate pentahydrate (Zr(NO3)4·5H2O) and 6.64 g of citric acid (C6H8O7), dissolve them in 100 mL of deionized water at 600 rad / min, and mechanically stir for 20 min to obtain mixed solution A.

[0060] (2) Prepare mixed solution B: Weigh 3 g of sodium hydroxide (NaOH) and dissolve it in 30 mL of deionized water. Add the prepared alkali solution dropwise into mixed solution A at 400 rad / min until the pH of mixed solution A reaches 10. Continue stirring at 400 rad / min for 30 min to obtain mixed solution B.

[0061] (3) Place the mixed solution B obtained in step (2) in a 100°C water bath and continue stirring at 400 rad / min until it becomes a transparent gel. Place the gel in an 80°C oven and dry for 12 hours to obtain ZrO2 precursor C.

[0062] (4) The precursor obtained in step (3) is placed in a muffle furnace and calcined at 450°C for 4 hours in an air atmosphere to obtain white ZrO2 powder, which is the zirconium oxide catalyst.

[0063] Comparative Example 2

[0064] The preparation method of the metal-modified zirconium oxide catalyst in this example specifically includes the following steps:

[0065] (1) Preparation of soluble nitrate mixed solution A: 9.22 g of zirconium nitrate pentahydrate (Zr(NO3)4·5H2O) and 6.64 g of citric acid (C6H8O7) were weighed and dissolved in 100 mL of deionized water under stirring at 600 rad / min and mechanically stirred for 20 min to obtain mixed solution A.

[0066] (2) Prepare mixed solution B: Weigh 3 g of sodium hydroxide (NaOH) and dissolve it in 30 mL of deionized water. Add the prepared alkali solution dropwise into mixed solution A at 400 rad / min until the pH of mixed solution A reaches 10. Continue stirring at 400 rad / min for 30 min to obtain mixed solution B.

[0067] (3) Place the mixed solution B obtained in step (2) in a 100°C water bath and continue stirring at 400 rad / min until it becomes a transparent gel. Place the gel in an 80°C oven and dry for 12 hours to obtain ZrO2 precursor C.

[0068] (4) The precursor obtained in step (3) was placed in a muffle furnace and calcined at 450°C for 4 h in an air atmosphere to obtain white ZrO2 powder.

[0069] (5) The ZrO2 powder obtained in step (4) was stirred and dissolved in 30 mL of deionized water, and La(NO3)3·6H2O powder was added to the solution (the molar ratio of La(NO3)3·6H2O to ZrO2 powder was 1:20), and the mixture was stirred for 30 min at 500 rad / min to obtain a mixed solution. The obtained mixed solution was placed in an oven at 80°C and dried for 12 h, and the dried solid was placed in a muffle furnace and calcined at 450°C in an air atmosphere for 4 h to obtain a product, which was recorded as LaZr 20 O z .

[0070] The catalysts prepared in Examples 1 to 4 and Comparative Examples 1 to 2 were subjected to catalyst performance testing and characterization:

[0071] When evaluating the performance of the catalyst, the catalysts prepared in Examples 1 to 4 and Comparative Examples 1 to 2 of the present invention should be made into catalyst particles of 20 to 40 meshes in order to make the catalyst particles uniform and not clog the reaction tube.

[0072] The catalysts prepared in Examples 1 to 4 and Comparative Examples 1 to 2 were evaluated in a micro-fixed reactor. The process conditions were as follows: 0.5 to 3 mL of 20 to 50 mesh catalyst, reaction temperature of 300 to 500° C., reaction pressure of 0.5 to 5 MPa, feed gas H2 / CO=1 or 2, and space velocity of 500 to 5000·h -1 .

[0073] For example, the LaCr prepared in Example 1 was subjected to 20 ZrO z The performance of the catalyst was evaluated. The specific operation steps were as follows: 1 mL of the perovskite-type zirconia catalyst prepared in Example 2 was weighed and loaded into the constant temperature zone in the middle of the reaction tube. The raw gas was H2 / CO=2, the temperature was 400°C, the pressure was 3 MPa, and the space velocity (GHSV) was 700 h -1 After reaching a steady state, sampling was performed at 3-hour intervals. Quantitative and qualitative analysis of the feed gas and products was performed using gas chromatography. The CO conversion rate and selectivity of each component were calculated using the methane correlation method described in "Determination of H₂, N₂, CO, CO₂, and C₁–C₁ Hydrocarbons in Coal-based Fischer-Tropsch Synthesis Tail Gas by Gas Chromatography." Detailed results are shown in Table 1.

[0074] Table 1 Comparison of process parameters and performance test results of CO-addition hydrogenation isomerization reaction of catalysts prepared in Examples 1 to 4 and Comparative Examples 1 to 2

[0075]

[0076] As can be seen from Table 1, in the distribution of hydrogenation products of the metal composite modified perovskite zirconia catalyst, the CO2 selectivity is maintained at about 50%. Compared with the perovskite catalyst prepared by the traditional hydrothermal method, the LaCrZrO prepared by the sol-gel method in this method is superior to the LaCrZrO z The catalyst powder particle size is smaller, which is conducive to the dispersion of active components. Compared with unmodified ZrO2, the metal composite modified LaZr 20 O z and LaCrZrO z CO conversion rate of the catalyst and i-C4 ＝ The selectivity ratio is improved. Compared with LaZr which only introduces La element 20 O z Compared with the catalysts, the catalytic performance of the series of catalysts introduced with CrO3 is more obvious. ＝ The significant improvement in selectivity is attributed to the lattice distortion of the catalyst formed by the doping of La and Cr. In addition, CrO3 undergoes a redox reaction with the alkali solution in the raw material, which promotes a higher mobility of oxygen atoms. The more abundant oxygen vacancies inside the catalyst are conducive to the formation of methoxy intermediates, promoting the isomerization reaction and increasing the i-C4 ＝ The acidic oxide CrO3 reacts with the alkali solution in the raw material to neutralize the reaction. Therefore, the pH value of the solution can be adjusted during the catalyst preparation process by changing the CrO3 content. The design has both high CO conversion rate and high i-C4 ＝ Selective reaction conditions.

[0077] Four composite modified ZrO2 catalysts with different La(NO3)3·6H2O and CrO3 contents were compared, among which LaCrZr 100 The Oz catalyst has the best catalytic effect, with a selectivity of 80.2% for light olefins, 65.4% for isobutylene, and an olefin-to-alkane ratio (O / P) of 10.8. This indicates that the introduction of appropriate amounts of La(NO3)3·6H2O and CrO3 causes the catalyst lattice to distort, which is beneficial to increasing the oxygen vacancy content of the catalyst. The increase in the number of oxygen vacancies is conducive to the interaction between CO and the catalyst surface to generate more methoxy intermediates, which is beneficial to improving the CO conversion rate and i-C4 ＝ Moreover, the acidic oxide CrO3 undergoes redox reaction under alkaline conditions, which increases the oxygen vacancy content of the catalyst and can also appropriately adjust the pH value of the catalyst, thus maintaining a high CO conversion rate while having a high i-C4 ＝ Selective.

[0078] The metal composite modified perovskite-type zirconia catalyst prepared by the present invention effectively solves the problem of low CO conversion rate in the isomerization synthesis reaction. The introduction of La and Cr elements promotes lattice distortion, increases the migration ability of lattice oxygen, and the formation of a large number of oxygen vacancies is beneficial to improving the redox properties of the catalyst.

[0079] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. Application of a metal composite modified perovskite-type zirconium oxide catalyst in catalyzing CO hydrogenation to synthesize isobutylene, characterized in that: The preparation method of the metal composite modified perovskite-type zirconium oxide catalyst comprises the following steps: (1) A soluble zirconium salt, citric acid, and deionized water are mixed in a certain proportion to obtain a mixed solution A; the ratio of the soluble zirconium salt, citric acid, and deionized water is (8-10) g: (5-10) g: (60-90) mL; (2) adding alkali solution dropwise to mixed solution A to obtain mixed solution B; the ratio of solute to deionized water in the alkali solution is (5-10) g: (20-50) mL; (3) Place the mixed solution B in a water bath and stir at a constant temperature until it becomes a transparent gel. After the gel is cooled to room temperature, it is dried to obtain the precursor C; (4) calcining the precursor C to obtain ZrO2 powder; (5) ZrO2 powder is dissolved in deionized water to obtain a solution, and appropriate amounts of La(NO3)3·6H2O and CrO3 are poured into the above solution and stirred, and then dried and calcined to obtain a metal composite modified perovskite-type zirconia catalyst; wherein the molar ratio of La(NO3)3·6H2O and CrO3 to ZrO2 powder is 1:1:(20~200).

2. Use of the metal composite modified perovskite-type zirconia catalyst according to claim 1 in catalyzing CO hydrogenation to synthesize isobutylene, characterized in that: In step (1), the soluble zirconium salt is any one of zirconium sulfate, zirconium acetate or zirconium nitrate pentahydrate.

3. Use of the metal composite modified perovskite-type zirconia catalyst according to claim 1 in catalyzing CO hydrogenation to synthesize isobutylene, characterized in that: In step (2), the solute in the alkali solution is any one of sodium hydroxide, potassium hydroxide, and calcium hydroxide.

4. Use of the metal composite modified perovskite-type zirconia catalyst according to claim 1 in catalyzing CO hydrogenation to synthesize isobutylene, characterized in that: In step (2), alkaline solution is added dropwise to the mixed solution A to control the pH value of the mixed solution B to be 8-10.

5. Use of the metal composite modified perovskite-type zirconia catalyst according to claim 1 in catalyzing CO hydrogenation to synthesize isobutylene, characterized in that: In step (4), the precursor C is calcined at 400-500° C. in an air atmosphere for 3-6 hours.

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