Solar-driven CO2 capture cracking catalyst, preparation method and application

Abstract

The invention relates to the technical field of preparation of catalysts, in particular to a solar-driven CO2 trapping and cracking catalyst, a preparation method and application, and the solar-driven CO2 trapping and cracking catalyst comprises the following components in parts by mass: 50-70 parts of a solid metal-based carrier precursor, 10-15 parts of a metal salt solution, 5-8 parts of a modified impregnation liquid, 20-30 parts of a reaction medium and 8-12 parts of a modified doping liquid. Through the one-step hydrothermal synthesis and co-impregnation process, the preparation process is simplified, the traditional complex process of separation after CO2 capture is omitted, the comprehensive cost is reduced by more than 30%, and the traditional high-energy-consumption carbon dioxide pressure swing adsorption and temperature swing adsorption technology is completely eliminated.

Description

Technical Field

[0001] This invention relates to the field of catalyst preparation technology, specifically to a solar-driven CO2 capture and cracking catalyst, its preparation method, and its application. Background Technology

[0002] The overuse of fossil fuels emits large amounts of carbon dioxide (CO2), a major greenhouse gas contributing to global warming. Carbon capture, utilization, and storage (CCUS) technology is an effective method for reducing atmospheric greenhouse gases. At the same time, CO2 is also an important C1 resource, used in the production of various carbon-containing chemicals and has wide applications. Directly capturing and utilizing CO2 from the atmosphere would not only effectively reduce greenhouse gas emissions but also generate significant economic benefits.

[0003] Solar energy can be used to catalytically convert CO2 under relatively mild conditions to obtain high-value-added chemicals. Similarly, as a clean and renewable energy source, solar energy is considered a future alternative to fossil fuels. Combining solar energy with CO2 capture and utilization can turn CO2 "waste" into valuable products.

[0004] Currently, mainstream CCUS technology is very expensive, hindering large-scale application. Similarly, the kinetic and thermodynamic stability of CO2 makes its high-value conversion and utilization extremely challenging. CO2 cracking is an important means of CO2 conversion and utilization, yielding high-value-added carbon products. However, the C=O bond energy of CO2 is very high, requiring significant energy consumption for the reaction. In existing reports on CO2 cracking processes, catalysts suffer from coking and deactivation due to carbon deposition, severely impacting catalyst lifespan. All of these factors are detrimental to CO2 capture and conversion.

[0005] The system and method of using solar energy to drive CO2 capture, separation and utilization can avoid the problems existing in the above process: (1) Direct capture and utilization of CO2 in the air can avoid the complex procedures in CO2 capture, reduce costs and facilitate large-scale utilization; (2) CO2 is cracked in a molten medium, where the density of the molten medium is greater than that of the generated carbon material. The carbon particles generated during the CO2 cracking process can float on the surface of the molten medium, which can not only avoid the problem of catalyst coking and deactivation and extend service life, but also facilitate the separation of the generated carbon material; (3) The energy required for CO2 cracking can be supplied by clean and regenerated solar energy, avoiding the problem of additional greenhouse gas emissions caused by high energy consumption. my country's western region is rich in solar energy resources. Therefore, the development of a solar energy-driven CO2 capture and cracking catalyst will bring about a huge change in the field of solar thermal energy and CO2 capture, separation and utilization.

[0006] Industries such as coal-fired power plants and combined cycle power plants (coal-fired and natural gas-fired) not only contain gases like methane and N2, but also have high CO2 content. Developing a solar-driven CO2 capture and cracking catalyst will help selectively capture and separate CO2 from gases in power plants and other similar applications, without affecting other components of the gas, and can also yield high-value-added carbon products. This will have a positive promoting effect on greenhouse gas emission reduction and environmental sustainable development. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a solar-driven CO2 capture and cracking catalyst, its preparation method, and its application.

[0008] To achieve the above objectives, the present invention provides the following technical solution: A solar-driven CO2 capture and cracking catalyst comprises, by mass parts: 50-70 parts of solid metal-based support precursor, 10-15 parts of metal salt solution, 5-8 parts of modified impregnation solution, 20-30 parts of reaction medium, and 8-12 parts of modified doping solution. The modified impregnation solution includes the following preparation steps: S21. Dissolve 10-13 parts of 3-aminopropyltriethoxysilane in 50-55 parts of ethanol, stir and mix evenly to obtain a preliminary mixture; S22. Add 1-3 parts of cerium nitrate and 0.5-1 parts of modifier to the preliminary mixture, and reflux for 1-2 hours under a water bath heating condition of 60°C to generate the secondary mixture; S23. After cooling the mixture from the second step to room temperature, filter it to obtain the modified impregnation solution; The preparation of the modified doped solution includes the following steps: S31. Dissolve 5-8 parts of polyethyleneimine in 45-50 parts of deionized water to obtain a polyethyleneimine solution; S32. Add 2-4 parts of tetraethoxysilane to the polyethyleneimine solution and ultrasonically disperse for 15-20 min to form a uniform alkaline doping solution; S33. Adjust the pH of the uniform alkaline dopant solution to 9-10 using dilute hydrochloric acid or ammonia, and let it stand for 10-12 hours to obtain the modified dopant solution.

[0009] Preferably, the mass ratio of polyethylene glycol to 1-butyl-3-methylimidazolium tetrafluoroborate in the modifier is 2-5:1.

[0010] Preferably, the stirring speed during the preparation of the modified impregnation solution is 400-500 r / min.

[0011] Preferably, the stirring speed during the preparation of the modified dopant solution is 300-400 r / min.

[0012] Preferably, the frequency of ultrasonic dispersion in step S22 is 40 kHz.

[0013] Preferably, the solid metal matrix carrier precursor is two or more combinations of carbon nanofibers, SiO2, TiO2, Al2O3, and MgO.

[0014] Preferably, the metal salt solution is one or a combination of MnCl2, KCl, FeCl3, NaCl, KBr, NaBr, and CaCl2.

[0015] Preferably, the reaction medium is one or more combinations of gallium, bismuth, tin, nickel, iron, copper, indium, silver, cobalt, magnesium, and platinum.

[0016] A method for preparing the above-mentioned solar-driven CO2 capture and cracking catalyst includes the following preparation steps: S1. Mix the solid metal-based support precursor with deionized water, and then hydrothermally synthesize it in a hydrothermal reactor at 180-220℃ for 12-14 hours, followed by calcination at 300-600℃ for 2-4 hours to obtain a porous support. S2. The metal salt solution and the modified impregnation solution are co-impregnated on a porous support, dried and dispersed in anhydrous ethanol, and refluxed at 80-120℃ for 6-12h. After filtration, washing with deionized water and drying at 80-120℃, a catalyst precursor supported on the active component is obtained. S3. The reaction medium and the modified dopant solution are mixed and then combined with the catalyst precursor supported on the active component obtained in step S2. After drying, the solar-driven CO2 capture and cracking catalyst is finally obtained.

[0017] An application of the solar-driven CO2 capture and cracking catalyst described above in carbon dioxide capture and conversion.

[0018] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention forms high-density alkaline sites on the carrier surface by using modified impregnation liquid and modified doping liquid in combination, which significantly improves the CO2 chemical adsorption efficiency, constructs a hydrophobic protective layer, and inhibits carbon deposition. At the same time, cerium oxide (CeO2) acts as a co-catalyst to promote the oxygen cycle of CO2 cracking reaction, thereby increasing the photothermal catalytic conversion efficiency to over 85%.

[0019] 2. This invention utilizes solar energy as the energy source for CO2 cracking, eliminating the need for additional high-energy-consuming equipment, reducing greenhouse gas emissions, and coupling the capture and conversion steps to reduce energy consumption, making it suitable for solar-powered systems.

[0020] 3. By using a one-step hydrothermal synthesis and co-impregnation process, the catalyst preparation process is simplified, eliminating the complex steps of traditional CO2 capture and separation, reducing the overall cost by more than 30%, and completely eliminating the need for traditional high-energy-consuming carbon dioxide pressure swing adsorption and temperature swing adsorption technologies. Attached Figure Description

[0021] Figure 1 This is a process flow diagram for preparing the solar-driven CO2 capture and cracking catalyst of the present invention; Figure 2 This is a flow chart of the preparation process of the modified impregnation solution of the present invention; Figure 3 This is a process flow diagram for preparing the modified doped liquid of the present invention; Figure 4 The TEM-EDS spectra of the solar-driven CO2 capture and cracking catalyst obtained in Example 4 of the present invention are shown below (wherein, Figure a is the TEM image of the catalyst at 200 nm, Figure b is the high-angle annular dark field scanning transmission imaging frame of the catalyst, Figure c is the high-angle annular dark field imaging HAADF image of the catalyst, Figure d is the C element in the EDS mapping analysis of the catalyst, Figure e is the O element in the EDS mapping analysis of the catalyst, Figure f is the Ga element in the EDS mapping analysis of the catalyst, and Figure g is the In element in the EDS mapping analysis of the catalyst). Detailed Implementation

[0022] The present invention will now be clearly and completely described in conjunction with embodiments thereof. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0023] Please see Figure 1-4 The present invention provides a technical solution: Example 1 A solar-driven CO2 capture and cracking catalyst: S1. Mix 25g carbon nanofibers, 25g SiO2 and deionized water, and then hydrothermally synthesize them in a hydrothermal reactor at 180℃ for 12h. After calcination at 300℃ for 2h, a porous carrier is obtained. Before proceeding to step S2, the modified impregnation solution is prepared, which includes the following steps: S21. Dissolve 10g of 3-aminopropyltriethoxysilane in 50g of ethanol, stir and mix evenly to obtain a preliminary mixture; S22. Add 1g of cerium nitrate and 0.5g of modifier (the mass ratio of polyethylene glycol to 1-butyl-3-methylimidazolium tetrafluoroborate is 2:1) to the preliminary mixture, and reflux for 1h under a water bath heating condition of 60℃ to generate the secondary mixture; S23. After cooling the mixture from the second step to room temperature, filter it to obtain the modified impregnation solution; S2. 10g MnCl2 and 5g of the above modified impregnation solution were co-impregnated on a porous support, dried and dispersed in anhydrous ethanol, and refluxed at 80°C for 6h. After filtration, washing with deionized water and drying at 80°C, the catalyst precursor supported on the active component was obtained. Before proceeding to step S3, the modified doping solution is prepared, which includes the following steps: S31. Dissolve 5g of polyethyleneimine in 45g of deionized water and stir until completely dissolved to obtain a polyethyleneimine solution; S32. Add 2g of tetraethoxysilane to the polyethyleneimine solution and ultrasonically disperse for 15min to form a uniform alkaline doped solution; S33. Adjust the pH of the uniform alkaline dopant solution to 9 using dilute hydrochloric acid or ammonia, and let it stand for 10 hours to age, thus obtaining the modified dopant solution. S3. Mix 10g gallium, 10g tin and the above-mentioned 8g modified dopant solution and then combine them with the catalyst precursor supported on the active component obtained in step S2. After drying, the solar-driven CO2 capture and cracking catalyst is finally obtained.

[0024] Example 2 A solar-driven CO2 capture and cracking catalyst: S1. Mix 35g TiO2 and 35g Al2O3 with deionized water, and then hydrothermally synthesize them in a hydrothermal reactor at 220℃ for 14h. After calcining at 600℃ for 4h, a porous support is obtained. Before proceeding to step S2, the modified impregnation solution is prepared, which includes the following steps: S21. Dissolve 13g of 3-aminopropyltriethoxysilane in 55g of ethanol, stir and mix evenly to obtain a preliminary mixture; S22. Add 3g of cerium nitrate and 1g of modifier (the mass ratio of polyethylene glycol to 1-butyl-3-methylimidazolium tetrafluoroborate is 5:1) to the preliminary mixture, and reflux for 2 hours under a water bath heating condition of 60°C to generate the secondary mixture; S23. After cooling the mixture from the second step to room temperature, filter it to obtain the modified impregnation solution; S2. 15g KCl and the above-mentioned 8g modified impregnation solution were co-impregnated on a porous support, dried and dispersed in anhydrous ethanol, and refluxed at 120℃ for 12h. After filtration, washing with deionized water and drying at 120℃, the catalyst precursor supported on the active component was obtained. Before proceeding to step S3, the modified doping solution is prepared, which includes the following steps: S31. Dissolve 8g of polyethyleneimine in 50g of deionized water and stir until completely dissolved to obtain a polyethyleneimine solution; S32. Add 4g of tetraethoxysilane to the polyethyleneimine solution and ultrasonically disperse for 20min to form a uniform alkaline doping solution; S33. Adjust the pH of the uniform alkaline dopant solution to 10 using dilute hydrochloric acid or ammonia, and let it stand for 12 hours to age, thus obtaining the modified dopant solution. S3. Mix 15g gallium, 15g bismuth and the above-mentioned 12g modified doping liquid, and then combine them with the catalyst precursor supported on the active component obtained in step S2. After drying, the solar-driven CO2 capture and cracking catalyst is finally obtained.

[0025] Example 3 A solar-driven CO2 capture and cracking catalyst: S1. Mix 30gAl2O3 and 30gMgO with deionized water, and then hydrothermally synthesize them in a hydrothermal reactor at 200℃ for 13h, followed by calcination at 400℃ for 3h to obtain a porous support. Before proceeding to step S2, the modified impregnation solution is prepared, which includes the following steps: S21. Dissolve 11g of 3-aminopropyltriethoxysilane in 52g of ethanol, stir and mix evenly to obtain a preliminary mixture; S22. Add 2g of cerium nitrate and 0.6g of modifier (the mass ratio of polyethylene glycol to 1-butyl-3-methylimidazolium tetrafluoroborate is 3:1) to the preliminary mixture, and reflux for 1.5h under water bath heating at 60℃ to generate the secondary mixture; S23. After cooling the mixture from the second step to room temperature, filter it to obtain the modified impregnation solution; S2. 12g FeCl3 and the above-mentioned 6g modified impregnation solution were co-impregnated on a porous support, dried and dispersed in anhydrous ethanol, and refluxed at 90℃ for 7h. After filtration, washing with deionized water and drying at 90℃, the catalyst precursor supported on the active component was obtained. Before proceeding to step S3, the modified doping solution is prepared, which includes the following steps: S31. Dissolve 6g of polyethyleneimine in 46g of deionized water and stir until completely dissolved to obtain a polyethyleneimine solution; S32. Add 3g of tetraethoxysilane to the polyethyleneimine solution and ultrasonically disperse for 17min to form a uniform alkaline doping solution; S33. Adjust the pH of the uniform alkaline doping solution to 9.5 using dilute hydrochloric acid or ammonia, and let it stand for 11 hours to age, thus obtaining the modified doping solution. S3. Mix 12g gallium, 12g nickel and the above-mentioned 9g modified doping liquid and then combine them with the catalyst precursor loaded with the active components obtained in step S2. After drying, the solar-driven CO2 capture and cracking catalyst is finally obtained.

[0026] Example 4 A solar-driven CO2 capture and cracking catalyst: S1. Mix 33g carbon nanofibers and 31g MgO with deionized water, and then hydrothermally synthesize them in a hydrothermal reactor at 208℃ for 13.5h. After calcination at 510℃ for 3h, a porous support is obtained. Before proceeding to step S2, the modified impregnation solution is prepared, which includes the following steps: S21. Dissolve 12.5g of 3-aminopropyltriethoxysilane in 53.5g of ethanol, stir and mix evenly to obtain a preliminary mixture; S22. Add 2.4g of cerium nitrate and 0.85g of modifier (the mass ratio of polyethylene glycol to 1-butyl-3-methylimidazolium tetrafluoroborate is 4:1) to the preliminary mixture, and reflux for 1.6h under a water bath heating condition of 60℃ to generate the secondary mixture; S23. After cooling the mixture from the second step to room temperature, filter it to obtain the modified impregnation solution; S2. 13.5g NaCl and the above-mentioned 7.5g modified impregnation solution were co-impregnated on a porous support, dried and dispersed in anhydrous ethanol, and refluxed at 100℃ for 11h. After filtration, washing with deionized water and drying at 100℃, the catalyst precursor supported on the active component was obtained. Before proceeding to step S3, the modified doping solution is prepared, which includes the following steps: S31. Dissolve 7.5g of polyethyleneimine in 47g of deionized water and stir until completely dissolved to obtain a polyethyleneimine solution; S32. Add 3.2g of tetraethoxysilane to a polyethyleneimine solution and ultrasonically disperse for 17min to form a uniform alkaline doped solution; S33. Adjust the pH of the uniform alkaline doping solution to 9.5 using dilute hydrochloric acid or ammonia, and let it stand for 11 hours to age, thus obtaining the modified doping solution. S3. Mix 10g gallium, 8g indium, 7g tin and the above-mentioned 10.5g modified dopant solution and then combine it with the catalyst precursor supported on the active component obtained in step S2. After drying, the solar-driven CO2 capture and cracking catalyst is finally obtained.

[0027] Comparative Example 1 A solar-driven CO2 capture and cracking catalyst: S1. Mix 25g carbon nanofibers, 25g SiO2 and deionized water, and then hydrothermally synthesize them in a hydrothermal reactor at 180℃ for 12h. After calcination at 300℃ for 2h, a porous carrier is obtained. S2. 10g MnCl2 was impregnated in a porous support, dried and dispersed in anhydrous ethanol, and refluxed at 80℃ for 6h. After filtration, washing with deionized water and drying at 80℃, a catalyst precursor supported on the active component was obtained. Before proceeding to step S3, the modified doping solution is prepared, which includes the following steps: S31. Dissolve 5g of polyethyleneimine in 45g of deionized water and stir until completely dissolved to obtain a polyethyleneimine solution; S32. Add 2g of tetraethoxysilane to the polyethyleneimine solution and ultrasonically disperse for 15min to form a uniform alkaline doped solution; S33. Adjust the pH of the uniform alkaline dopant solution to 9 using dilute hydrochloric acid or ammonia, and let it stand for 10 hours to age, thus obtaining the modified dopant solution. S3. Mix 10g gallium, 10g tin and the above-mentioned 8g modified dopant solution and then combine them with the catalyst precursor supported on the active component obtained in step S2. After drying, the solar-driven CO2 capture and cracking catalyst is finally obtained.

[0028] Comparative Example 2 A solar-driven CO2 capture and cracking catalyst: S1. Mix 25g carbon nanofibers, 25g SiO2 and deionized water, and then hydrothermally synthesize them in a hydrothermal reactor at 180℃ for 12h. After calcination at 300℃ for 2h, a porous carrier is obtained. Before proceeding to step S2, the modified impregnation solution is prepared, which includes the following steps: S21. Dissolve 10g of 3-aminopropyltriethoxysilane in 50g of ethanol, stir and mix evenly to obtain a preliminary mixture; S22. Add 1g of cerium nitrate and 0.5g of modifier (the mass ratio of polyethylene glycol to 1-butyl-3-methylimidazolium tetrafluoroborate is 2:1) to the preliminary mixture, and reflux for 1h under a water bath heating condition of 60℃ to generate the secondary mixture; S23. After cooling the mixture from the second step to room temperature, filter it to obtain the modified impregnation solution; S2. 10g MnCl2 and 5g of the above modified impregnation solution were co-impregnated on a porous support, dried and dispersed in anhydrous ethanol, and refluxed at 80°C for 6h. After filtration, washing with deionized water and drying at 80°C, the catalyst precursor supported on the active component was obtained. S3. Combine 10g gallium and 10g tin with the catalyst precursor supported on the active components obtained in step S2, and dry them to finally obtain a solar-driven CO2 capture and cracking catalyst.

[0029] Performance testing: The adsorption performance of the solar-driven CO2 capture and cracking catalysts prepared in Examples 1-4 and Comparative Examples 1-2 was evaluated using a thermogravimetric adsorption (TGA) instrument. During the test, a small amount of the solar-driven CO2 capture and cracking catalyst sample was weighed and spread evenly in a sample tray. First, under an argon atmosphere, the temperature was raised to 500℃ at a rate of 10℃ / min and held for 2 hours to remove water and other impurities from the bifunctional catalyst. Then, the temperature was lowered to 250℃. At 250℃, the argon gas was switched to the experimental gas (15 vol.% CO2 - 50 vol.% N2 - 35 vol.% H2), and held for 2 hours. The adsorption capacity of the solar-driven CO2 capture and cracking catalysts in Examples 1-8 at 250℃ was obtained based on the mass change. The results are shown in Table 1 below. Table 1

[0030] The carbon dioxide conversion efficiency of the solar-driven CO2 capture and cracking catalysts prepared in Examples 1-4 and Comparative Examples 1-2 was tested using a photothermal catalytic reactor, employing a xenon lamp (AM1.5G, light intensity 100mW / cm²). 2 The conversion of carbon dioxide was achieved at 120℃ and a carbon dioxide flow rate of 20 ml / min, and the results are shown in Table 2 below: Table 2

[0031] When testing the carbon dioxide conversion efficiency of the solar-driven CO2 capture and cracking catalysts prepared in Examples 1-4 and Comparative Examples 1-2, the testing time was extended to 24 hours. The CO2 conversion rate was monitored over time, and the long-term stability was tested. The results are shown in Table 3 below: Table 3

[0032] The data obtained from Tables 1 and 2 show that the carbon dioxide adsorption capacity and conversion efficiency of Examples 1-4 are significantly higher than those of Comparative Examples 1-2. The modified impregnation solution and the modified dopant solution significantly improve the carbon dioxide adsorption performance and conversion efficiency of the solar-driven CO2 capture and cracking catalyst. Comparative Example 1 (without modified impregnation solution) suffers from poor adsorption capacity and conversion efficiency due to the unoptimized support. Comparative Example 2 (without modified dopant solution) has insufficient alkaline sites, resulting in poor carbon dioxide adsorption capacity and conversion efficiency. Carbon deposition occurred during the testing of the carbon dioxide conversion efficiency of the solar-driven CO2 capture and cracking catalyst prepared in Comparative Example 1. When the carbon dioxide conversion efficiency of the solar-driven CO2 capture and cracking catalysts prepared in Examples 1-4 and Comparative Examples 1-2 was tested using a photothermal catalytic reactor, the catalyst achieved efficient chemical adsorption of CO2 through the high-density alkaline sites constructed on its surface. Furthermore, the synergistic effect of the modified impregnation solution and the modified dopant solution formed a stable hydrophobic protective layer, effectively suppressing carbon deposition. The synergistic effect of the modified doping solution and the modified impregnation solution significantly improves the photothermal catalytic conversion efficiency, further optimizes the reaction interface characteristics, promotes the cracking reaction of CO2 on the catalyst surface, and the generated carbon particles are effectively separated due to the difference in surface hydrophobicity and density, thereby avoiding the active sites being covered, extending the catalyst lifespan, and facilitating the recycling of carbon materials.

[0033] The gallium oxide after the reaction can be reduced to elemental gallium by H2, thus enabling the catalyst to be recycled.

[0034] Table 3 shows that the solar-driven CO2 capture and cracking catalyst obtained in Example 1 has good long-term conversion stability, specifically due to the catalytic effect of the hydrophobic protective layer and the modified impregnation solution. After 24 hours, the conversion rate only decreased by 7%, demonstrating excellent stability. The solar-driven CO2 capture and cracking catalyst obtained in this invention, after composite modification, possesses both high capture and high conversion performance, reducing the overall cost by more than 30%. It completely eliminates the need for traditional high-energy-consuming CO2 pressure swing adsorption and temperature swing adsorption technologies, making it suitable for solar-driven systems.

[0035] The solar-driven CO2 capture and cracking catalyst obtained in Example 1 was characterized, and TEM-EDS spectra of the core-shell structured particles were obtained, as shown in the attached figure. Figure 4 As shown.

[0036] During the detection process, an oxide film forms on the surface of gallium, thus forming a core-shell structure. TEM-EDS detection shows that the catalyst is mainly composed of metallic Ga.

[0037] A relatively broad distribution of Ga, O, and In can be observed on the surface of the core-shell structured particles. EDS spectra also show enrichment of Sn and O in the shell region, with Ga and O overlapping with the enriched regions in the core. The core-shell structure design, by physically separating the active sites and the protective layer, not only improves the chemisorption efficiency of CO2 (basic sites in the shell) but also promotes the oxygen cycle of the CO2 cracking reaction through the Ga-based core, resulting in a carbon dioxide conversion rate of 89%.

[0038] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A solar-driven CO2 capture and cracking catalyst, characterized in that, The components, by weight, are: 50-70 parts solid metal-based carrier precursor, 10-15 parts metal salt solution, 5-8 parts modified impregnation solution, 20-30 parts reaction medium, and 8-12 parts modified doping solution. The modified impregnation solution includes the following preparation steps: S21. Dissolve 10-13 parts of 3-aminopropyltriethoxysilane in 50-55 parts of ethanol by mass, stir and mix evenly to obtain a preliminary mixture; S22. Add 1-3 parts of cerium nitrate and 0.5-1 parts of modifier to the preliminary mixture, and reflux for 1-2 hours under a water bath heating condition of 60°C to generate the secondary mixture; S23. After cooling the mixture from the second step to room temperature, filter it to obtain the modified impregnation solution; The mass ratio of polyethylene glycol to 1-butyl-3-methylimidazolium tetrafluoroborate in the modifier is 2-5:1; The preparation of the modified doped solution includes the following steps: S31. Dissolve 5-8 parts of polyethyleneimine in 45-50 parts of deionized water by mass, and stir until completely dissolved to obtain a polyethyleneimine solution; S32. Add 2-4 parts of tetraethoxysilane to the polyethyleneimine solution and ultrasonically disperse at a frequency of 40kHz for 15-20min to form a uniform alkaline doping solution. S33. Adjust the pH of the uniform alkaline dopant solution to 9-10 using dilute hydrochloric acid or ammonia, and let it stand for 10-12 hours to obtain the modified dopant solution.

2. The solar-driven CO2 capture and cracking catalyst according to claim 1, characterized in that, The stirring speed during the preparation of the modified impregnation solution is 400-500 r / min.

3. The solar-driven CO2 capture and cracking catalyst according to claim 1, characterized in that, The stirring speed during the preparation of the modified dopant solution is 300-400 r / min.

4. The solar-driven CO2 capture and cracking catalyst according to claim 1, characterized in that, The solid metal matrix carrier precursor is a combination of two or more of the following: carbon nanofibers, SiO2, TiO2, Al2O3, and MgO.

5. The solar-driven CO2 capture and cracking catalyst according to claim 1, characterized in that, The metal salt solution is one or a combination of MnCl2, KCl, FeCl3, NaCl, KBr, NaBr, and CaCl2.

6. The solar-driven CO2 capture and cracking catalyst according to claim 1, characterized in that, The reaction medium is one or more combinations of gallium, bismuth, tin, nickel, iron, copper, indium, silver, cobalt, magnesium, and platinum.

7. A method for preparing the solar-driven CO2 capture and cracking catalyst according to any one of claims 1-6, characterized in that, The preparation steps include the following: S1. Mix the solid metal-based support precursor with deionized water, and then hydrothermally synthesize it in a hydrothermal reactor at 180-220℃ for 12-14 hours, followed by calcination at 300-600℃ for 2-4 hours to obtain a porous support. S2. The metal salt solution and the modified impregnation solution are co-impregnated on the porous support, dried and dispersed in anhydrous ethanol, and refluxed at 80-120℃ for 6-12h. After filtration, washing with deionized water and drying at 80-120℃, the catalyst precursor supported on the active component is obtained. S3. The reaction medium and the modified dopant solution are mixed and then combined with the catalyst precursor supported on the active component obtained in step S2. After drying, the solar-driven CO2 capture and cracking catalyst is finally obtained.

8. The application of a solar-driven CO2 capture and cracking catalyst according to any one of claims 1-6 or a solar-driven CO2 capture and cracking catalyst prepared by the preparation method according to claim 7 in carbon dioxide capture and conversion.

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