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 capturing and cracking catalyst, a preparation method and application, and the preparation method comprises the following steps: S1, mixing a solid metal-based carrier precursor with deionized water, performing hydrothermal synthesis in a hydrothermal reaction kettle at 180-220 DEG C for 12-14 hours, and calcining at 300-600 DEG C for 2-4 hours to obtain a porous carrier; s2, co-impregnating a porous carrier with a metal salt solution and the modified impregnation liquid, drying, and calcining in a nitrogen atmosphere at 300-600 DEG C for 2-6 hours to obtain an active component supported catalyst precursor; and S3, mixing a reaction medium and a modified doping solution, compounding with the active component loaded catalyst precursor obtained in the step S2, and drying to obtain the solar-driven CO2 capture cracking catalyst. 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] The present invention relates to the technical field of catalyst preparation, and particularly to a solar-driven CO2 capture and cracking catalyst, a preparation method and an application thereof. Background Art

[0002] The excessive utilization of fossil fuels emits a large amount of carbon dioxide (CO2), and CO2 is currently the main greenhouse gas causing global warming. Carbon capture utilization and storage (CCUS) technology is an effective method to reduce greenhouse gases in the atmosphere. At the same time, CO2 is also an important C1 resource and can be used to produce various carbon-containing chemicals, with a wide range of applications. Under the background of "dual carbon", if CO2 in the air can be directly captured and utilized, it can not only effectively achieve greenhouse gas emission reduction, but also generate huge economic benefits.

[0003] Solar energy can be used to catalytically convert CO2 into high-value chemicals under relatively mild conditions. Similarly, solar energy, as a clean and renewable energy source, is regarded as a substitute for future fossil energy. Combining solar energy with CO2 capture and utilization to "turn waste into treasure" and obtain high-value products is crucial for China to achieve carbon peak and carbon neutrality.

[0004] Currently, the mainstream CCUS technology is very expensive and not conducive to large-scale use. Similarly, the stability of CO2 in terms of kinetics and thermodynamics makes the high-value conversion and utilization of CO2 extremely challenging. CO2 cracking is an important means of CO2 conversion and utilization, and high-value carbon products can be obtained. However, the C=O bond energy of CO2 is very high, and the reaction requires a very high energy consumption. In the reported CO2 cracking process, the catalyst suffers from coking deactivation due to carbon deposition, seriously affecting the service life of the catalyst. All of the above are not conducive to CO2 capture and conversion and utilization.

[0005] The use of solar-driven CO2 capture, separation and utilization systems and methods can avoid the problems existing in the above process: (1) Directly capturing and utilizing CO2 in the air can avoid the complex process in the CO2 capture process, 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 the generated carbon material. The carbon particles generated during the cracking of CO2 can float on the surface of the molten medium, which can not only avoid the problem of catalyst coking and deactivation, but also extend the service life, and the generated carbon material is also easy to separate; (3) The energy required for CO2 cracking can be supplied by clean and renewable 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, so the development of a solar-driven CO2 capture and cracking catalyst will bring great changes to the field of solar thermal energy and CO2 capture, separation and utilization.

[0006] Coal-fired thermal power plants, coal gas and natural gas combined cycle power plants and other industries not only contain methane, N2 and other gases, but also have a high content of CO2. The development of a solar-driven CO2 capture and cracking catalyst will help to selectively capture and separate CO2 from gases such as power plants, while not affecting other components in the gas, and can also obtain high value-added carbon products. This will have a positive role in promoting greenhouse gas emission reduction and environmental sustainable development. Summary of the invention

[0007] In view of the deficiencies of the prior art, the object of the present invention is to provide a solar-driven CO2 capture and cracking catalyst, a preparation method and an application.

[0008] To achieve the above object, the present invention provides the following technical solutions: A solar-driven CO2 capture and cracking catalyst comprises, by weight: 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 solution, 20-30 parts of a reaction medium, and 8-12 parts of a modified doping solution; The modified impregnation solution comprises the following preparation steps: S21. Dissolve 10-13 parts of 3-aminopropyltriethoxysilane in 50-55 parts of ethanol and stir to mix well to obtain a preliminary mixed solution; S22. Add 1-3 parts of cerium nitrate and 0.5-1 parts of a modifier to the preliminary mixture, and reflux for 1-2 hours in a water bath at 60°C to generate a secondary mixed solution; S23. The mixed solution in the second step is cooled to room temperature and filtered to obtain a modified impregnation solution; The preparation of the modified doping solution comprises 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 it for 15 - 20 min to form a uniform alkaline doping solution; S33. Adjust the pH of the uniform alkaline doping solution to 9 - 10 with dilute hydrochloric acid or ammonia water, and let it stand and age for 10 - 12 h to obtain a modified doping 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 doping solution is 300 - 400 r / min.

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

[0013] Preferably, the solid metal - based carrier precursor is a combination of two or more of carbon nanofibers, SiO2, TiO2, Al2O3, and MgO.

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

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

[0016] A preparation method for the above - mentioned solar - driven CO2 capture and cracking catalyst, comprising the following preparation steps: S1. Mix the solid metal - based carrier precursor with deionized water, perform hydrothermal synthesis in a hydrothermal reaction kettle at 180 - 220 °C for 12 - 14 h, and then calcine it at 300 - 600 °C for 2 - 4 h to obtain a porous carrier; S2. Co - impregnate the metal salt solution and the modified impregnation solution on the porous carrier, dry it, and then calcine it in a nitrogen atmosphere at 300 - 600 °C for 2 - 6 h to obtain a catalyst precursor loaded with active components; S3. Mix the reaction medium and the modified doping solution, and then compound them with the catalyst precursor loaded with active components obtained in step S2, and finally obtain the solar - driven CO2 capture and cracking catalyst after drying.

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

[0018] Compared with the prior art, the beneficial effects of the present invention are: 1. The present invention forms high-density basic sites on the surface of the carrier through the combined use of a modified impregnation solution and a modified doping solution, significantly improving the CO2 chemisorption efficiency, constructing a hydrophobic protective layer to inhibit carbon deposition. At the same time, cerium oxide (CeO2) is used as a co-catalyst to promote the oxygen cycle of the CO2 cracking reaction, increasing the photothermal catalytic conversion efficiency to over 85%.

[0019] 2. The present invention uses solar energy as the energy source for CO2 cracking, eliminating the need for additional high-energy-consuming equipment, reducing greenhouse gas emissions, coupling the capture and conversion steps, reducing energy consumption, and being applicable to solar-driven systems.

[0020] 3. Through a one-step hydrothermal synthesis and co-impregnation process, the catalyst preparation process is simplified, eliminating the complex procedures of traditional post-CO2 capture separation. The comprehensive cost is reduced by more than 30%, completely getting rid of the traditional high-energy-consuming carbon dioxide pressure swing adsorption and temperature swing adsorption technologies. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is the process flow chart for the preparation of the solar-driven CO2 capture and cracking catalyst of the present invention; Figure 2 is the process flow chart for the preparation of the modified impregnation solution of the present invention; Figure 3 is the process flow chart for the preparation of the modified doping solution of the present invention; Figure 4 is the TEM-EDS spectrum of the solar-driven CO2 capture and cracking catalyst obtained in Example 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] The present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0023] Please refer to Figures 1-4 , the present invention provides a technical solution: Example 1 A solar-driven CO2 capture and cracking catalyst: S1. Mix 25 g of carbon nanofibers, 25 g of SiO2 with deionized water, hydrothermally synthesize at 180 °C for 12 h in a hydrothermal reaction kettle, and then calcine at 300 °C for 2 h to obtain a porous carrier; Before performing step S2, the preparation of the modified impregnation solution is carried out first, which includes the following steps: S21. Dissolve 10 g of 3-aminopropyltriethoxysilane in 50 g of ethanol, stir and mix evenly to obtain a preliminary mixture; S22. Add 1 g of cerium nitrate and 0.5 g of modifier (the mass ratio of polyethylene glycol to 1-butyl-3-methylimidazolium tetrafluoroborate is 2:1) to the preliminary mixture, and reflux for 1 h under the condition of water bath heating at 60 °C to generate a secondary mixture; S23. Cool the secondary mixture to room temperature and then filter it to obtain a modified impregnating solution; S2. Co-impregnate 10 g of MnCl2 with 5 g of the above-mentioned modified impregnating solution on a porous support, dry it, and then calcine it in a nitrogen atmosphere at 300 °C for 2 h to obtain a catalyst precursor loaded with active components; Before performing step S3, first prepare a modified doping solution, which includes the following steps: S31. Dissolve 5 g of polyethyleneimine in 45 g of deionized water, stir until completely dissolved to obtain a polyethyleneimine solution; S32. Add 2 g of tetraethoxysilane to the polyethyleneimine solution, and ultrasonically disperse it for 15 min to form a uniform alkaline doping solution; S33. Adjust the pH of the uniform alkaline doping solution to 9 with dilute hydrochloric acid or ammonia water, and let it stand and age for 10 h to obtain a modified doping solution; S3. Mix 10 g of gallium, 10 g of tin and 8 g of the above-mentioned modified doping solution, and then compound them with the catalyst precursor loaded with active components obtained in step S2, and finally obtain a solar-driven CO2 capture and cracking catalyst after drying.

[0024] Example 2 A solar-driven CO2 capture and cracking catalyst: S1. Mix 35 g of TiO2, 35 g of Al2O3 with deionized water, carry out hydrothermal synthesis in a hydrothermal reaction kettle at 220 °C for 14 h, and then calcine it at 600 °C for 4 h to obtain a porous support; Before performing step S2, first prepare a modified impregnating solution, which includes the following steps: S21. Dissolve 13 g of 3-aminopropyltriethoxysilane in 55 g of ethanol, stir and mix evenly to obtain a preliminary mixture; S22. Add 3 g of cerium nitrate and 1 g 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 h under the condition of water bath heating at 60 °C to generate a secondary mixture; S23. Cool the secondary mixture to room temperature and then filter it to obtain a modified impregnating solution; S2. Co-impregnate 15 g of KCl and the above-mentioned 8 g of modified impregnation solution onto the porous support, dry it, and then calcine it in a nitrogen atmosphere at 600 °C for 6 h to obtain a catalyst precursor loaded with active components; Before performing step S3, prepare the modified doping solution first, which includes the following steps: S31. Dissolve 8 g of polyethyleneimine in 50 g of deionized water and stir until completely dissolved to obtain a polyethyleneimine solution; S32. Add 4 g of tetraethoxysilane to the polyethyleneimine solution and ultrasonically disperse it for 20 min to form a uniform basic doping solution; S33. Adjust the pH of the uniform basic doping solution to 10 with dilute hydrochloric acid or ammonia water, and let it stand and age for 12 h to obtain the modified doping solution; S3. Mix 15 g of gallium, 15 g of bismuth and the above-mentioned 12 g of modified doping solution, and then compound it with the catalyst precursor loaded with active components obtained in step S2. After drying, finally obtain a solar-driven CO2 capture and cracking catalyst.

[0025] Example 3 A solar-driven CO2 capture and cracking catalyst: S1. Mix 30 g of Al2O3, 30 g of MgO with deionized water, hydrothermally synthesize it in a hydrothermal reaction kettle at 200 °C for 13 h, and then calcine it at 400 °C for 3 h to obtain a porous support; Before performing step S2, prepare the modified impregnation solution first, which includes the following steps: S21. Dissolve 11 g of 3-aminopropyltriethoxysilane in 52 g of ethanol, stir and mix evenly to obtain a preliminary mixture; S22. Add 2 g of cerium nitrate and 0.6 g of modifier (the mass ratio of polyethylene glycol to 1-butyl-3-methylimidazolium tetrafluoroborate is 3:1) to the preliminary mixture, and reflux it for 1.5 h under the condition of water bath heating at 60 °C to generate a secondary mixture; S23. Cool the secondary mixture to room temperature and then filter it to obtain the modified impregnation solution; S2. Co-impregnate 12 g of FeCl3 and the above-mentioned 6 g of modified impregnation solution onto the porous support, dry it, and then calcine it in a nitrogen atmosphere at 400 °C for 3 h to obtain a catalyst precursor loaded with active components; Before performing step S3, prepare the modified doping solution first, which includes the following steps: S31. Dissolve 6 g of polyethyleneimine in 46 g of deionized water and stir until completely dissolved to obtain a polyethyleneimine solution; S32. Add 3 g of tetraethoxysilane to the polyethyleneimine solution and ultrasonically disperse it for 17 min to form a uniform basic doping solution; S33. Adjust the pH of the uniform basic doping solution to 9.5 with dilute hydrochloric acid or ammonia water, and let it stand for aging for 11 h to obtain a modified doping solution; S3. Mix 12 g of gallium, 12 g of nickel and the above 9 g of modified doping solution, and then compound with the catalyst precursor loaded with active components obtained in step S2, and finally obtain a solar-driven CO2 capture and cracking catalyst after drying.

[0026] Example 4 A solar-driven CO2 capture and cracking catalyst: S1. Mix 35 g of carbon nanofibers, 30 g of MgO with deionized water, carry out hydrothermal synthesis at 210 °C for 13 h in a hydrothermal reaction kettle, and then calcine at 500 °C for 3.5 h to obtain a porous support; Before carrying out step S2, first prepare a modified impregnation solution, which includes the following steps: S21. Dissolve 12 g of 3-aminopropyltriethoxysilane in 54 g of ethanol, stir and mix evenly to obtain a preliminary mixed solution; S22. Add 2.5 g of cerium nitrate and 0.8 g of modifier (the mass ratio of polyethylene glycol to 1-butyl-3-methylimidazolium tetrafluoroborate is 4:1) to the preliminary mixed solution, and reflux for 1.5 h under the condition of water bath heating at 60 °C to generate a secondary mixed solution; S23. Cool the secondary mixed solution to room temperature and then filter it to obtain a modified impregnation solution; S2. Co-impregnate 14 g of NaCl and the above 7 g of modified impregnation solution on the porous support, dry it, and then calcine it in a nitrogen atmosphere at 500 °C for 5 h to obtain a catalyst precursor loaded with active components; Before carrying out step S3, first prepare a modified doping solution, which includes the following steps: S31. Dissolve 7 g of polyethyleneimine in 48 g of deionized water, stir until completely dissolved to obtain a polyethyleneimine solution; S32. Add 3.5 g of tetraethoxysilane to the polyethyleneimine solution, and ultrasonically disperse it for 18 min to form a uniform basic doping solution; S33. Adjust the pH of the uniform basic doping solution to 9.5 with dilute hydrochloric acid or ammonia water, and let it stand for aging for 11.5 h to obtain a modified doping solution; S3. Mix 14 g of iron, 14 g of copper and the above 11 g of modified doping solution, and then compound with the catalyst precursor loaded with active components obtained in step S2, and finally obtain a solar-driven CO2 capture and cracking catalyst after drying.

[0027] Comparative Example 1 A solar-driven CO2 capture and cracking catalyst: S1. Mix 25 g of carbon nanofibers, 25 g of SiO2 with deionized water, perform hydrothermal synthesis in a hydrothermal reactor at 180 °C for 12 h, and then calcine at 300 °C for 2 h to obtain a porous support; S2. Immerse 10 g of MnCl2 in the porous support, dry it, and then calcine it in a nitrogen atmosphere at 300 °C for 2 h to obtain a catalyst precursor loaded with active components; Before performing step S3, first prepare a modified doping solution, which includes the following steps: S31. Dissolve 5 g of polyethyleneimine in 45 g of deionized water, stir until completely dissolved to obtain a polyethyleneimine solution; S32. Add 2 g of tetraethoxysilane to the polyethyleneimine solution, and ultrasonically disperse it for 15 min to form a uniform basic doping solution; S33. Adjust the pH of the uniform basic doping solution to 9 using dilute hydrochloric acid or ammonia water, and let it stand and age for 10 h to obtain a modified doping solution; S3. Mix 10 g of gallium, 10 g of tin and 8 g of the above-mentioned modified doping solution, and then compound with the catalyst precursor loaded with active components obtained in step S2, and finally obtain a solar-driven CO2 capture and cracking catalyst after drying.

[0028] Comparative Example 2 A solar-driven CO2 capture and cracking catalyst: S1. Mix 25 g of carbon nanofibers, 25 g of SiO2 with deionized water, perform hydrothermal synthesis in a hydrothermal reactor at 180 °C for 12 h, and then calcine at 300 °C for 2 h to obtain a porous support; Before performing step S2, first prepare a modified impregnation solution, which includes the following steps: S21. Dissolve 10 g of 3-aminopropyltriethoxysilane in 50 g of ethanol, stir and mix evenly to obtain a preliminary mixture; S22. Add 1 g of cerium nitrate and 0.5 g of a modifier (the mass ratio of polyethylene glycol to 1-butyl-3-methylimidazolium tetrafluoroborate is 2:1) to the preliminary mixture, and reflux for 1 h under the condition of water bath heating at 60 °C to generate a secondary mixture; S23. Cool the secondary mixture to room temperature and then filter it to obtain a modified impregnation solution; S2. Co-impregnate 10 g of MnCl2 and 5 g of the above-mentioned modified impregnation solution on the porous support, dry it, and then calcine it in a nitrogen atmosphere at 300 °C for 2 h to obtain a catalyst precursor loaded with active components; S3. Compound 10 g of gallium, 10 g of tin with the catalyst precursor loaded with active components obtained in step S2, and finally obtain a solar-driven CO2 capture and cracking catalyst after drying.

[0029] Performance test: 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 sorption analyzer. During the test, a small amount of the solar-driven CO2 capture and cracking catalyst sample was weighed and evenly spread on the sample tray. First, it was heated to 500 °C at a rate of 10 °C / min under an argon atmosphere purge and held at a constant temperature for 2 h to remove the water and other impurities of the bifunctional catalyst. Then, it was cooled to 250 °C. At 250 °C, the argon was switched to the experimental gas (15 vol.% CO2 - 85 vol.% N2), and it was held at a constant temperature for 2 h. According to the mass change, the CO2 adsorption amount of the solar-driven CO2 capture and cracking catalysts in Examples 1-8 at 250 °C was obtained. The results are shown in Table 1 below: Table 1

[0030] The CO2 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. Using a xenon lamp (AM1.5G, light intensity 100 mW / cm 2 ), the conversion of CO2 was achieved at 120 °C and a CO2 flow rate of 20 ml / min. The results are shown in Table 2 below: Table 2

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

[0032] Among the data obtained from Table 1 and Table 2, the carbon dioxide adsorption amounts and conversion efficiencies of Examples 1-4 are significantly higher than those of Comparative Examples 1-2. The modified impregnation solution and the modified doping solution have greatly improved the carbon dioxide adsorption performance and conversion efficiency of the solar-driven CO2 capture and cracking catalyst. In Comparative Example 1 (without the modified impregnation solution), the carrier was not optimized, which affected the adsorption amount and conversion efficiency; in Comparative Example 2 (without the modified doping solution), the lack of basic sites resulted in poor carbon dioxide adsorption ability and conversion efficiency. Among them, carbon deposition occurred during the test of the carbon dioxide conversion efficiency of the solar-driven CO2 capture and cracking catalyst obtained in Comparative Example 1. 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 using a photothermal catalytic reactor, at 120 °C, gallium was in a liquid state and wrapped on the surface of the catalyst, making the prepared catalyst a liquid-solid system, realizing the direct separation of the carbon particles generated by the cracking of carbon dioxide, avoiding catalyst coking deactivation, improving the catalyst life, and facilitating the recovery of carbon materials.

[0033] The results in Table 3 show that the solar-driven CO2 capture and cracking catalyst obtained in Example 1 has good long-term conversion stability. Specifically, due to the co-catalytic effects of the hydrophobic protective layer and the modified impregnation solution, the conversion rate only decreased by 7% after 24 hours, and the stability is excellent. The solar-driven CO2 capture and cracking catalyst obtained in the present invention has both high capture and high conversion performance after composite modification, and the comprehensive cost is reduced by more than 30%. It completely gets rid of the traditional high-energy-consuming carbon dioxide pressure swing adsorption and temperature swing adsorption technologies and is applicable to solar-driven systems.

[0034] By performing characterization tests on the solar-driven CO2 capture and cracking catalyst obtained in Example 1, the TEM-EDS spectra of the core-shell structure particles were obtained, as shown in the appendix Figure 4 as follows. A relatively broad distribution of Ga, O, and Sn can be seen on the surface of the core-shell structure particles. The EDS spectrum also shows the enrichment of Sn and O in the shell region, and the enrichment regions of Ga and O overlap with those in the core. The design of the core-shell structure physically separates the active sites from the protective layer, which not only improves the chemical adsorption efficiency of CO2 (basic sites in the shell layer), 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%.

[0035] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A solar-driven CO2 capture and cracking catalyst, characterized in that, By mass parts, it includes: 50 - 70 parts of solid metal-based carrier precursor, 10 - 15 parts of metal salt solution, 5 - 8 parts of modified impregnation solution, 20 - 30 parts of reaction medium, 8 - 12 parts of modified doping solution; The preparation of the modified impregnation solution includes the following steps: S21. By mass parts, 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 part of modifier to the preliminary mixture, reflux for 1 - 2 h under the condition of water bath heating at 60 °C to generate a secondary mixture; S23. Cool the secondary mixture to room temperature and then filter it to obtain the modified impregnation solution.

2. The solar-driven CO2 capture and cracking catalyst according to claim 1, wherein In the modifier, the mass ratio of polyethylene glycol to 1-butyl-3-methylimidazolium tetrafluoroborate is 2 - 5:

1.

3. The solar-driven CO2 capture and cracking catalyst according to claim 1, wherein The preparation of the modified doping solution includes the following steps: S31. By mass parts, dissolve 5 - 8 parts of polyethyleneimine in 45 - 50 parts of deionized water, stir until completely dissolved to obtain a polyethyleneimine solution; S32. Add 2 - 4 parts of tetraethoxysilane to the polyethyleneimine solution, and ultrasonically disperse it at a frequency of 40 kHz for 15 - 20 min to form a uniform alkaline doping solution; S33. Adjust the pH of the uniform alkaline doping solution to 9 - 10 with dilute hydrochloric acid or ammonia water, and let it stand and age for 10 - 12 h to obtain the modified doping solution.

4. The solar-driven CO2 capture and cracking catalyst according to claim 1, wherein During the preparation of the modified impregnation solution, the stirring speed is 400 - 500 r / min.

5. The solar-driven CO2 capture and cracking catalyst according to claim 1, wherein During the preparation of the modified doping solution, the stirring speed is 300 - 400 r / min.

6. The solar-driven CO2 capture and cracking catalyst according to claim 1, wherein The solid metal-based carrier precursor is a combination of two or more of carbon nanofibers, SiO2, TiO2, Al2O3, and MgO.

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

8. A solar-driven CO2 capture and cracking catalyst according to claim 1, wherein The reaction medium is a combination of one or more of gallium, bismuth, tin, nickel, iron, copper, indium, silver, cobalt, magnesium, and platinum.

9. A preparation method for preparing the solar-driven CO2 capture and cracking catalyst according to any one of claims 1-8, characterized in that, It includes the following preparation steps: S1. Mix the solid metal-based carrier precursor with deionized water, perform hydrothermal synthesis in a hydrothermal reaction kettle at 180 - 220 °C for 12 - 14 h, and then calcine it at 300 - 600 °C for 2 - 4 h to obtain a porous carrier; S2. Co-impregnate the metal salt solution and the modified impregnation solution on the porous carrier, dry it, and then calcine it in a nitrogen atmosphere at 300 - 600 °C for 2 - 6 h to obtain a catalyst precursor loaded with active components; S3. Mix the reaction medium and the modified doping solution, and then compound them with the catalyst precursor loaded with active components obtained in step S2, and finally obtain a solar-driven CO2 capture and cracking catalyst after drying.

10. Use of the solar-driven CO2 capture and cracking catalyst according to any one of claims 1 - 8 or the solar-driven CO2 capture and cracking catalyst prepared by the preparation method according to claim 9 in carbon dioxide capture and conversion.

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