Preparation of metal organic framework catalytic material and application of metal organic framework catalytic material in radiation activation CO2 catalytic reduction

Abstract

The invention discloses preparation of a metal organic framework catalytic material and application of the metal organic framework catalytic material in radiation activation CO2 catalytic reduction. The preparation comprises the following steps: synthesizing a metal organic framework UiO-66; the phosphomolybdic acid is loaded on the metal organic framework UiO-66 to obtain the metal organic framework catalytic material. Aiming at the problem of low CO2 conversion rate in a plasma-driven CO2 and H2O reaction system, the metal organic framework catalytic material is successfully prepared, and activation and conversion of CO2 are effectively enhanced. Under normal-temperature and normal-pressure plasma reaction conditions, the phosphomolybdic acid / UiO-66 catalytic system realizes 17.78% of CO2 conversion rate which is increased by about 3 times compared with an unmodified material system and is about 6 times of that of a control group only using plasma, the key effect of a hydrogen bond microenvironment is further proved, the quenching effect of gas-phase water molecules on the plasma-induced CO2 dissociation process is effectively inhibited, and the CO2 dissociation efficiency is improved. And the free energy barrier of reducing CO2 into * COOH is reduced, so that the reaction kinetics of converting CO2 into CO is accelerated.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of catalytic material preparation, and more particularly, the application relates to a kind of metal organic framework catalytic material and its application in the radiation activation CO2 catalytic reduction. BACKGROUND

[0002] The continuous increase of CO2 emissions brings severe social and environmental challenges, which promotes the extensive exploration of CO2 resource utilization technology. In recent years, low-temperature plasma in the field of plasma radiation technology has shown great potential. This technology generates high-energy electrons by applying an electric field in a gas, and these electrons collide non-elastically with gas molecules to generate a large number of active species (such as ions, excited particles and free radicals), thereby triggering a series of rapid chemical reactions to achieve thermodynamically unfavorable chemical reactions under mild conditions. Compared with pure thermal catalytic process, plasma catalysis not only breaks through the thermodynamic equilibrium limit, but also activates the catalyst surface in the plasma environment to further improve the reaction efficiency. In addition, the plasma catalytic technology has the flexibility of quick start and stop, which can adapt to the power supply of fluctuating renewable energy (such as solar energy and wind energy), providing a feasible path for CO2 resource utilization.

[0003] The co-conversion of CO2 and H2O to generate syngas, hydrocarbons and other energy products using water as a hydrogen source provides a potential way to alleviate the energy crisis and mitigate climate change. However, the introduction of H2O will have a significant quenching effect on the plasma CO2 dissociation process, resulting in a decrease in CO2 conversion rate. Therefore, developing efficient catalysts to regulate the reaction path and inhibit side reactions is an effective strategy to improve the performance of plasma-driven CO2 / H2O conversion. Currently, catalyst design mainly focuses on the optimization of active components. Studies have shown that precise design of the local reaction microenvironment of the catalyst can also effectively improve the performance of plasma catalytic CO2 / H2O co-conversion. UiO-66, as a typical metal organic framework material, has high specific surface area, porous structure and good stability, making it an ideal catalyst carrier. Its rich pore structure not only facilitates the contact between reactants and active sites, but also promotes surface discharge and micro-discharge behavior during dielectric barrier discharge, enhancing the synergy between plasma and catalyst. Phosphomolybdic acid (PMA) contains a large number of exposed oxygen, which can form a hydrogen bond network local microenvironment around it through hydrogen bond interaction with adsorbed H2O molecules, enhancing the capture and activation of water molecules to promote CO2 hydrogenation, while the hydrogen bond microenvironment induces the enrichment and activation of water molecules on the material, reducing the concentration of free-state water in the gas phase, effectively weakening the adverse effects of H2O molecules on plasma CO2 dissociation. SUMMARY

[0004] An object of the present application is to solve at least the above problems and / or drawbacks and to provide at least the advantages later described.

[0005] To achieve these objects and other advantages in accordance with the purpose of the present application, a method for preparing a metal organic framework catalytic material is provided, comprising the steps of: Step one, synthesizing metal organic framework UiO-66 using zirconium source and terephthalic acid; Step two, loading phosphomolybdic acid onto the metal organic framework UiO-66 by a solvothermal method to obtain the metal organic framework catalytic material.

[0006] Preferably, in the step one, the specific method for synthesizing metal organic framework UiO-66 using zirconium source and terephthalic acid comprises: S11, dissolving zirconium source, terephthalic acid, acetic acid and deionized water in N,N-dimethylformamide to obtain a mixed solution; S12, transferring the obtained mixed solution into a polytetrafluoroethylene lined high-pressure reaction kettle and heating for a certain time; S13, after cooling to room temperature, the obtained powder is separated by centrifugation and washed with N,N-dimethylformamide, methanol and acetone for several times, and then dried to obtain the metal organic framework UiO-66.

[0007] Preferably, in the S11, the zirconium source is zirconium tetrachloride; The amount ratio of the zirconium tetrachloride, terephthalic acid, acetic acid and deionized water, N,N-dimethylformamide is 6-7 mmol:6-7 mmol:10-15 mL:600-700 μL:40-60 mL.

[0008] Preferably, in the S12, the heating temperature is 110-130℃ and the heating time is 12-48h.

[0009] Preferably, in the S13, the drying temperature is 50-80℃ and the drying time is 6-12h.

[0010] Preferably, the specific method of the step two comprises: S21, dispersing the metal organic framework UiO-66 and phosphomolybdic acid in a mixed solution of anhydrous ethanol and deionized water to obtain a mixture; S22, transferring the mixture into a polytetrafluoroethylene lined hydrothermal reaction kettle for solvothermal reaction; S23, after the reaction is completed, the solid product is washed with deionized water and anhydrous ethanol, and dried at 50-80℃ for 6-12h to obtain the metal organic framework catalytic material.

[0011] Preferably, in the S21, the amount ratio of the metal-organic framework UiO-66, phosphomolybdic acid and the mixed solution is 0.06-0.07 mmol:0.005-0.02 mmol:50-100 mL; and the volume ratio of anhydrous ethanol and deionized water in the mixed solution is 1:1. In the S22, the heating temperature of the solvothermal reaction is 90-110℃, and the reaction time is 6-24h.

[0012] Preferably, in the step two, the metal-organic framework catalytic material is further doped with 1%-10% of C3N5 / MXene composite powder based on the mass of the phosphomolybdic acid, and the preparation method of the C3N5 / MXene composite powder comprises the following steps: S1, CuCl2 powder and Ti3SiC2 powder are mixed in a molar ratio of 10-15:1, then loaded into a tube furnace, sealed, and argon is introduced to remove air in the furnace; the temperature is raised to 700-800℃ at a rate of 5℃ / min, and the temperature is kept for 2-12h; the solid after reaction is ground into powder, washed with HCl and deionized water for several times, and vacuum dried at 60℃ for 3h to obtain MXene powder; S2, 3-amino-1,2,4-triazole and thiourea are mixed in a molar ratio of 3:1, then calcined at 500-600℃ for 2-6h, then the product is transferred to a reaction kettle and hydrothermally reacted at 160-180℃ for 12-24h, and then washed and dried to obtain C3N5 powder; S3, the MXene powder and the C3N5 powder are dispersed in deionized water respectively to obtain MXene dispersion and C3N5 dispersion respectively; the MXene dispersion and the C3N5 dispersion are mixed in a volume ratio of 2-3:1, and (3-aminopropyl)triethoxysilane accounting for 1%-10% of the mass of the MXene powder is added, the temperature is raised to 60-80℃, and the mixture is stirred for 6-12h; the solid is collected by centrifugation, and freeze-dried to obtain C3N5 / MXene composite powder; wherein, the amount ratio of MXene to deionized water is 1g-3g:100-200mL, and the amount ratio of C3N5 to deionized water is 2-5g:100-300mL.

[0013] The application of a metal-organic framework catalytic material is applied to radiation activation and catalytic reduction of CO2, and CO2 and H2O are adsorbed and activated by phosphomolybdic acid / UiO-66 under plasma radiation conditions, and CO2 and H2O are catalyzed to generate H2, CO, O2 and hydrocarbons; the hydrocarbons include CH4, C2H2, C2H4, C2H6 and C3H8.

[0014] Preferably, the metal organic framework catalytic material is filled in the discharge gap of the dielectric barrier discharge plasma reactor, fixed by quartz wool at both ends of the dielectric barrier discharge plasma reactor, and then H2O humidified CO2 gas is introduced into the dielectric barrier discharge plasma reactor at a flow rate of 10-40 mL / min; by adjusting the voltage and current of the plasma experimental power supply, the input power is changed, and before each discharge, humidified CO2 gas is introduced to purge for a certain time, and H2O and CO2 are catalytically generated into H2, CO, O2 and hydrocarbons; The structure of the dielectric barrier discharge plasma reactor comprises: An outer quartz tube wrapped with aluminum foil, one end of the outer quartz tube is provided with an air inlet, and the other end of the outer quartz tube is provided with a product outlet; the outer quartz tube is connected with the ground electrode of the plasma power supply; the outer quartz tube is sealed at both ends by polytetrafluoroethylene joints; An inner quartz tube placed inside the outer quartz tube along the axis, the inner quartz tube is provided with a stainless steel rod, and the stainless steel rod is connected with the high-voltage electrode of the plasma power supply; the discharge gap is located between the outer quartz tube and the inner quartz tube.

[0015] The present application at least includes the following beneficial effects: the present application aims at the low CO2 conversion rate in the plasma-driven CO2 and H2O reaction system, and successfully prepares a metal organic framework catalytic material by using a solvothermal-electrostatic self-assembly strategy to confine Keggin-type phosphomolybdic acid (PMA) in metal organic framework UiO-66, which effectively enhances the activation and conversion of CO2. 1 By means of solid-state nuclear magnetic hydrogen spectrum (H NMR) and other spectral techniques, it is successfully proved that the introduction of PMA forms a hydrogen bond network structure by combining with water vapor in the reaction system, thereby improving the hydrophilicity of the catalyst and the adsorption capacity of CO2. Under the condition of plasma input power of 12W, the phosphomolybdic acid / UiO-66 catalytic system realizes a CO2 conversion rate of 17.78%, which is nearly 3 times higher than that of the unmodified material system, about 6 times of the control group using only plasma, further proving the key role of the hydrogen bond microenvironment. Density functional theory (DFT) calculation shows that the hydrogen bond microenvironment significantly reduces the adsorption energy of H2O and CO2 (-0.149eV and -0.01eV, respectively) by enhancing the enrichment and activation of reactants on the material surface, thereby effectively inhibiting the quenching effect of gas-phase water molecules on the plasma-induced CO2 dissociation process. At the same time, the hydrogen bond network can act as an electron capture center to stabilize the key reaction intermediates, reduce the free energy barrier of CO2 reduction to *COOH (carboxyl intermediate adsorbed on the catalyst surface), and thus accelerate the reaction kinetics of CO2 to CO conversion.

[0016] The metal organic framework catalytic material (PMA / UiO-66) prepared by the application is used for adsorbing and activating CO2 and H2O, and catalyzing CO2 and H2O to generate H2, CO, O2 and hydrocarbons; the metal organic framework catalytic material not only improves the conversion rate of the reactants CO2 and H2O, but also changes the reaction path. Compared with UiO-66, the metal organic framework catalytic material significantly improves the generation concentration of C2-C3 hydrocarbons, mainly C2H6, and the concentration can reach 4790 ppm. The rich pore structure of the UiO-66 carrier not only promotes the surface discharge and micro-discharge behavior in the dielectric barrier discharge process, enhances the synergy between the plasma and the catalyst, but also enhances the local enrichment of CO on the surface of the catalytic material, increases the C-C coupling process, and thus promotes the conversion of CO2 to C2-C3 and other high hydrocarbons. The introduction of PMA further promotes the coupling of carbon-containing intermediates and enhances the directional conversion of C2H4, C2H6 and other C2-C3 hydrocarbons.

[0017] In another scheme of the application, when the metal organic framework catalytic material is prepared by solvothermal method, C3N5 / MXene composite powder is added to the reaction system, so that the metal organic framework catalytic material with a heterojunction structure is prepared; the results show that the metal organic framework catalytic material obtained by this scheme can further improve the conversion rate of CO2 when applied to the catalytic reaction of CO2. By using the rich basic sites and high electron transfer capacity of C3N5 and the high conductivity and metallicity of MXene, the charge separation in the catalytic reaction is promoted, and an acid-base-oxidation-reduction synergistic system is formed by combining the acidic sites of phosphomolybdic acid (PMA) and the pore confinement effect of UiO-66. This scheme significantly improves the conversion and catalytic efficiency of CO2.

[0018] Other advantages, objects, and features of the application will be apparent from the following description, and will be understood by those skilled in the art through practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is a schematic diagram of the cross-sectional structure of a dielectric barrier discharge plasma reactor; Figure 2 It is an SEM image of the metal organic framework UiO-66; Figure 3 It is an SEM image of the metal organic framework catalytic material prepared in Example 1; Figure 4 It is an HRTEM image of the metal organic framework catalytic material prepared in Example 1; Figure 5 It is an EDS image of the metal organic framework catalytic material prepared in Example 1; Figure 6XRD patterns of metal organic framework catalytic materials prepared for Examples 1-3 and PMA, UiO-66; Figure 7 FTIR patterns of metal organic framework catalytic materials prepared for Examples 1-3 and PMA, UiO-66; Figure 8 Raman spectra of metal organic framework catalytic material prepared for Example 1 and PMA, UiO-66; Figure 9 N2adsorption-desorption isotherms of metal organic framework catalytic material prepared for Example 1 and UiO-66; Figure 10 Pore size distribution curves of metal organic framework catalytic material prepared for Example 1 and UiO-66; Figure 11 Thermogravimetric curves of metal organic framework catalytic material prepared for Example 1 and UiO-66; Figure 12 Static water contact angle images of metal organic framework catalytic material prepared for Example 1 and UiO-66; Figure 13 CO2adsorption isotherms of metal organic framework catalytic material prepared for Example 1 and UiO-66; Figure 14 Water adsorption isotherms of metal organic framework catalytic material prepared for Example 1 and UiO-66; Figure 15 CO2conversion and H2yield of different PMA loadings of phosphomolybdic acid / UiO-66 in a dielectric barrier discharge plasma catalytic reactor packed with UiO-66, Examples 1-3; Figure 16 Yield of carbon-containing products of different PMA loadings of phosphomolybdic acid / UiO-66 in a dielectric barrier discharge plasma catalytic reactor packed with UiO-66, Examples 1-3; Figure 17 C2H4, C2H6, C2H2, C3H8product concentrations of different PMA loadings of phosphomolybdic acid / UiO-66 in a dielectric barrier discharge plasma catalytic reactor packed with UiO-66, Examples 1-3; Figure 18 Effect of different water vapor contents on CO2conversion when metal organic framework catalytic materials catalyze the reaction of CO2and H2O in a dielectric barrier discharge plasma reactor; Figure 19 Effect of different gas flow rates on CO2conversion when metal organic framework catalytic materials catalyze the reaction of CO2and H2O in a dielectric barrier discharge plasma reactor; Figure 20 Effect of different input power on CO2 conversion and energy efficiency of dielectric barrier discharge plasma; Figure 21 Free energy diagram for plasma catalyzed CO2 and H2O conversion to CO. DETAILED DESCRIPTION

[0020] The present application will be further described in conjunction with the drawings, so that those skilled in the art can implement the present application according to the description and the drawings.

[0021] It should be understood that the terms such as "have", "contain" and "include" used herein do not exclude the presence or addition of one or more other elements or combinations thereof. Example 1 A preparation method of a metal organic framework catalytic material, comprising the following steps: Step one, synthesis of metal organic framework UiO-66, the specific method comprising: S11, dissolve 6.249 mmol of zirconium tetrachloride, 6.25 mmol of terephthalic acid, 11.25 mL of acetic acid and 675 μL of deionized water in 50 mL of N,N-dimethylformamide (DMF) to obtain a mixed solution; S12, transfer the obtained mixed solution into a polytetrafluoroethylene lined high-pressure reaction kettle, and heat the reaction at 120℃ for 24h; S13, after cooling to room temperature, the obtained powder is separated by centrifugation, and washed with N,N-dimethylformamide, methanol and acetone for several times, and then dried at 60℃ for 12h to obtain the metal organic framework UiO-66; Step two, loading phosphomolybdic acid onto the metal organic framework UiO-66 by solvothermal method to obtain the metal organic framework catalytic material, the specific method comprising: S21, disperse 0.0601 mmol of metal organic framework UiO-66 and 0.0055 mmol of phosphomolybdic acid (10.0 g, PMA) in a mixed solution of 30 mL of anhydrous ethanol and 30 mL of deionized water, and stir for 30 min to obtain a mixture; S22, transfer the mixture into a polytetrafluoroethylene lined hydrothermal reaction kettle, and react at 100℃ for 12h; S23, after the reaction is completed, the solid product is washed with deionized water and anhydrous ethanol, and dried at 60℃ for 12h to obtain the metal organic framework catalytic material, which is recorded as PMA 10 / UiO-66.

[0022] Example 2 A preparation method of a metal organic framework catalytic material, comprising the following steps: Step one, synthesis of metal organic framework UiO-66, the specific method comprises: S11, 6.249mmol of zirconium tetrachloride, 6.25mmol of terephthalic acid, 11.25mL of acetic acid and 675μL of deionized water are dissolved in 50mL of N,N-dimethylformamide (DMF) to obtain a mixed solution; S12, the obtained mixed solution is transferred into a polytetrafluoroethylene lined high-pressure reaction kettle, and heated at 120℃ for 24h; S13, after cooling to room temperature, the obtained powder is separated by centrifugation, and washed with N,N-dimethylformamide, methanol and acetone for several times, and then dried at 60℃ for 12h to obtain metal organic framework UiO-66; Step two, load phosphomolybdic acid on metal organic framework UiO-66 by solvothermal method to obtain metal organic framework catalytic material, the specific method comprises: S21, 0.0601mmol of metal organic framework UiO-66 and 0.011mmol of phosphomolybdic acid (PMA) are dispersed in a mixed solution of 30mL of anhydrous ethanol and 30mL of deionized water, and stirred for 30min to obtain a mixture; S22, the mixture is transferred into a polytetrafluoroethylene lined hydrothermal reaction kettle, and reacted at 100℃ for 12h; S23, after the reaction is completed, the solid product is washed with deionized water and anhydrous ethanol, and dried at 60℃ for 12h to obtain metal organic framework catalytic material, which is recorded as PMA 20 / UiO-66.

[0023] Example 3 A preparation method of metal organic framework catalytic material, comprising the following steps: Step one, synthesis of metal organic framework UiO-66, the specific method comprises: S11, 6.249mmol of zirconium tetrachloride, 6.25mmol of terephthalic acid, 11.25mL of acetic acid and 675μL of deionized water are dissolved in 50mL of N,N-dimethylformamide (DMF) to obtain a mixed solution; S12, the obtained mixed solution is transferred into a polytetrafluoroethylene lined high-pressure reaction kettle, and heated at 120℃ for 24h; S13, after cooling to room temperature, the obtained powder is separated by centrifugation, and washed with N,N-dimethylformamide, methanol and acetone for several times, and then dried at 60℃ for 12h to obtain metal organic framework UiO-66; Step two, load phosphomolybdic acid on metal organic framework UiO-66 by solvothermal method to obtain metal organic framework catalytic material, the specific method comprises: S21. Disperse 0.0601 mmol of metal-organic framework UiO-66 and 0.0165 mmol of phosphomolybdic acid (PMA) in a mixed solution of 30 mL of anhydrous ethanol and 30 mL of deionized water, and stir for 30 min to obtain a mixture. S22. Transfer the mixture to a polytetrafluoroethylene-lined hydrothermal reactor and react at 100°C for 12 hours. S23. After the reaction is complete, the solid product is washed with deionized water and anhydrous ethanol, and dried at 60°C for 12 h to obtain a metal-organic framework catalytic material, denoted as PMA. 30 / UiO-66.

[0024] Example 4 A method for preparing a metal-organic framework catalytic material includes the following steps: Step 1: Synthesize the metal-organic framework UiO-66. Specific methods include: S11. Dissolve 6.249 mmol zirconium tetrachloride, 6.25 mmol terephthalic acid, 11.25 mL acetic acid and 675 μL deionized water in 50 mL N,N-dimethylformamide (DMF) to obtain a mixed solution. S12. Transfer the obtained mixed solution to a high-pressure reactor lined with polytetrafluoroethylene and heat it at 120°C for 24 hours. S13. After cooling to room temperature, the obtained powder was separated by centrifugation and washed multiple times with N,N-dimethylformamide, methanol and acetone. Then it was dried at 60°C for 12 hours to obtain metal-organic framework UiO-66. Step 2: C3N5 / MXene composite powder and phosphomolybdic acid are loaded onto the metal-organic framework UiO-66 via a solvothermal method to obtain the metal-organic framework catalytic material. Specific methods include: S21. Disperse 0.0601 mmol of metal-organic framework UiO-66, 1 g of C3N5 / MXene composite powder and 0.0055 mmol of phosphomolybdic acid (10.0 g, PMA) in a mixed solution of 30 mL of anhydrous ethanol and 30 mL of deionized water, and stir for 30 min to obtain a mixture. S22. Transfer the mixture to a polytetrafluoroethylene-lined hydrothermal reactor and react at 100°C for 12 hours. S23. After the reaction is complete, the solid product is washed with deionized water and anhydrous ethanol and dried at 60°C for 12 h to obtain the metal-organic framework catalytic material. The preparation method of C3N5 / MXene composite powder includes: S1. CuCl2 powder and Ti3SiC2 powder were mixed at a molar ratio of 10:1 and placed into a tube furnace. After sealing, argon gas was introduced to purge the air from the furnace. The temperature was increased to 800℃ at 5℃ / min and held for 12h. The solid after the reaction was ground into powder and washed multiple times with HCl and deionized water. After vacuum drying at 60℃ for 3h, MXene powder was obtained. S2. 3-Amino-1,2,4-triazole and thiourea were mixed in a molar ratio of 3:1 and calcined at 550°C for 5 hours. The product was then transferred to a reaction vessel and hydrothermally reacted at 180°C for 12 hours. After washing and drying, C3N5 powder was obtained. S3. Disperse 3g of MXene powder and 3g of C3N5 powder in 200mL of deionized water to obtain MXene dispersion and C3N5 dispersion, respectively. Mix MXene dispersion and C3N5 dispersion at a volume ratio of 3:1, add 0.2g of (3-aminopropyl)triethoxysilane, heat to 80℃, and stir for 12h. Collect the solid by centrifugation and freeze-dry to obtain C3N5 / MXene composite powder.

[0025] Comparative Example 1 A method for preparing a metal-organic framework catalytic material includes the following steps: Step 1: Synthesize the metal-organic framework UiO-66. Specific methods include: S11. Dissolve 6.249 mmol zirconium tetrachloride, 6.25 mmol terephthalic acid, 11.25 mL acetic acid and 675 μL deionized water in 50 mL N,N-dimethylformamide (DMF) to obtain a mixed solution. S12. Transfer the obtained mixed solution to a high-pressure reactor lined with polytetrafluoroethylene and heat it at 120°C for 24 hours. S13. After cooling to room temperature, the obtained powder was separated by centrifugation and washed multiple times with N,N-dimethylformamide, methanol and acetone. Then it was dried at 60°C for 12 hours to obtain metal-organic framework UiO-66. Step 2: C3N5 / MXene composite powder and phosphomolybdic acid are loaded onto the metal-organic framework UiO-66 via a solvothermal method to obtain the metal-organic framework catalytic material. Specific methods include: S21. Disperse 0.0601 mmol of metal-organic framework UiO-66, 1 g of C3N5 / MXene composite powder and 0.0055 mmol of phosphomolybdic acid (10.0 g, PMA) in a mixed solution of 30 mL of anhydrous ethanol and 30 mL of deionized water, and stir for 30 min to obtain a mixture. S22. Transfer the mixture to a polytetrafluoroethylene-lined hydrothermal reactor and react at 100°C for 12 hours. S23. After the reaction is complete, the solid product is washed with deionized water and anhydrous ethanol and dried at 60°C for 12 h to obtain the metal-organic framework catalytic material. The preparation method of C3N5 / MXene composite powder includes: S1. CuCl2 powder and Ti3SiC2 powder were mixed at a molar ratio of 10:1 and placed into a tube furnace. After sealing, argon gas was introduced to purge the air from the furnace. The temperature was increased to 800℃ at 5℃ / min and held for 12h. The solid after the reaction was ground into powder and washed multiple times with HCl and deionized water. After vacuum drying at 60℃ for 3h, MXene powder was obtained. S2. 3-Amino-1,2,4-triazole and thiourea were mixed in a molar ratio of 3:1 and calcined at 550°C for 5 hours. The product was then transferred to a reaction vessel and hydrothermally reacted at 180°C for 12 hours. After washing and drying, C3N5 powder was obtained. S3. Disperse 3g of MXene powder and 3g of C3N5 powder in 200mL of deionized water to obtain MXene dispersion and C3N5 dispersion, respectively. Mix the MXene dispersion and C3N5 dispersion at a volume ratio of 3:1, heat to 80℃, and stir for 12h. Collect the solids by centrifugation and freeze-dry to obtain C3N5 / MXene composite powder.

[0026] Comparative Example 2 A method for preparing a metal-organic framework catalytic material includes the following steps: Step 1: Synthesize the metal-organic framework UiO-66. Specific methods include: S11. Dissolve 6.249 mmol zirconium tetrachloride, 6.25 mmol terephthalic acid, 11.25 mL acetic acid and 675 μL deionized water in 50 mL N,N-dimethylformamide (DMF) to obtain a mixed solution. S12. Transfer the obtained mixed solution to a high-pressure reactor lined with polytetrafluoroethylene and heat it at 120°C for 24 hours. S13. After cooling to room temperature, the obtained powder was separated by centrifugation and washed multiple times with N,N-dimethylformamide, methanol and acetone. Then it was dried at 60°C for 12 hours to obtain metal-organic framework UiO-66. Step 2: C3N5 powder and phosphomolybdic acid are loaded onto the metal-organic framework UiO-66 via a solvothermal method to obtain the metal-organic framework catalytic material. Specific methods include: S21. Disperse 0.0601 mmol of metal-organic framework UiO-66, 1 g of C3N5 powder and 0.0055 mmol of phosphomolybdic acid (10.0 g, PMA) in a mixed solution of 30 mL of anhydrous ethanol and 30 mL of deionized water, and stir for 30 min to obtain a mixture. S22. Transfer the mixture to a polytetrafluoroethylene-lined hydrothermal reactor and react at 100°C for 12 hours. S23. After the reaction is complete, the solid product is washed with deionized water and anhydrous ethanol and dried at 60°C for 12 h to obtain the metal-organic framework catalytic material. The preparation method of C3N5 powder includes: mixing 3-amino-1,2,4-triazole and thiourea in a molar ratio of 3:1, calcining at 550°C for 5 hours, then transferring the product to a reaction vessel and hydrothermally reacting at 180°C for 12 hours, and finally washing and drying to obtain C3N5 powder.

[0027] Comparative Example 3 A method for preparing a metal-organic framework catalytic material includes the following steps: Step 1: Synthesize the metal-organic framework UiO-66. Specific methods include: S11. Dissolve 6.249 mmol zirconium tetrachloride, 6.25 mmol terephthalic acid, 11.25 mL acetic acid and 675 μL deionized water in 50 mL N,N-dimethylformamide (DMF) to obtain a mixed solution. S12. Transfer the obtained mixed solution to a high-pressure reactor lined with polytetrafluoroethylene and heat it at 120°C for 24 hours. S13. After cooling to room temperature, the obtained powder was separated by centrifugation and washed multiple times with N,N-dimethylformamide, methanol and acetone. Then it was dried at 60°C for 12 hours to obtain metal-organic framework UiO-66. Step 2: MXene powder and phosphomolybdic acid are loaded onto the metal-organic framework UiO-66 via a solvothermal method to obtain the metal-organic framework catalytic material. Specific methods include: S21. Disperse 0.0601 mmol of metal-organic framework UiO-66, 1 g of MXene powder and 0.0055 mmol of phosphomolybdic acid (10.0 g, PMA) in a mixed solution of 30 mL of anhydrous ethanol and 30 mL of deionized water, and stir for 30 min to obtain a mixture. S22. Transfer the mixture to a polytetrafluoroethylene-lined hydrothermal reactor and react at 100°C for 12 hours. S23. After the reaction is complete, the solid product is washed with deionized water and anhydrous ethanol and dried at 60°C for 12 h to obtain the metal-organic framework catalytic material. The preparation method of MXene powder includes: mixing CuCl2 powder and Ti3SiC2 powder at a molar ratio of 10:1 and loading them into a tube furnace, sealing the furnace and purging it with argon gas to remove air; heating the furnace to 800℃ at 5℃ / min and holding it at that temperature for 12h; grinding the solid after the reaction into powder and washing it multiple times with HCl and deionized water, and then drying it under vacuum at 60℃ for 3h to obtain MXene powder.

[0028] The experiment employed a dielectric barrier discharge plasma reactor to test the catalytic performance of the materials under ambient pressure. 0.2 g of the metal-organic framework catalytic material prepared in Examples 1-3 was filled into the discharge gap of the dielectric barrier discharge plasma reactor and fixed at both ends with quartz wool. Then, H2O-moistened CO2 gas was introduced into the dielectric barrier reactor at a flow rate of 10-40 mL / min. The input power was varied by adjusting the voltage and current of the plasma experimental power supply. Before each discharge, moistened CO2 gas was introduced to purge for 20 min to ensure the reactor was free of other gases. After the discharge stabilized, quantitative analysis of the gaseous and liquid components was performed. Gas products were measured three times under each experimental condition, and the average value was taken to minimize experimental error.

[0029] Among them, such as Figure 1 As shown, the structure of the dielectric barrier discharge plasma reactor includes: An outer quartz tube 1 is wrapped with aluminum foil. One end of the outer quartz tube 1 is provided with an air inlet, and the other end of the outer quartz tube is provided with a product outlet. The outer quartz tube is connected to the ground electrode of the plasma power supply. Both ends of the outer quartz tube are sealed with polytetrafluoroethylene connectors. The inner quartz tube 2 is placed inside the outer quartz tube 1 along the axis. A stainless steel rod 3 is installed inside the inner quartz tube 2. The stainless steel rod 3 is connected to the high-voltage electrode of the plasma power supply. The discharge gap 4 is located between the outer quartz tube 1 and the inner quartz tube 2.

[0030] To evaluate the catalytic performance of the catalyst, the following formulas were used to calculate key reaction performance indicators such as CO2 conversion rate, product yield, and CO2 conversion energy efficiency. The specific calculation method is as follows: CO2 conversion rate ( The result is calculated using the following formula: The yields of carbon monoxide, methane, and C2-C3 products can be calculated using the following formulas: The specific energy input (SEI) of dielectric barrier discharge plasma and the energy efficiency of CO2 conversion ( η The following formula is used to calculate: In the above formula, This represents the enthalpy of the CO2 decomposition reaction at 298K. This represents the enthalpy of the H2O decomposition reaction. , , and The values ​​represent the generation rates of CO, CH4, C2H6, and H2, respectively.

[0031] Scanning electron microscopy (SEM) images showed that phosphomolybdic acid / UiO-66 exhibited an octahedral morphology similar to the original UiO-66 support, with an average particle size of approximately 200 nm and a uniform particle size distribution. The introduction of PMA did not cause a significant change in the morphology of the UiO-66 support, indicating that a small amount of PMA loading does not cause structural collapse of the material (e.g., Figure 2 , Figure 3 (As shown). High-resolution transmission electron microscopy (HRTEM) further confirmed that the introduction of PMA did not alter the morphology of UiO-66. Figure 4 As shown, the phosphomolybdic acid / UiO-66 material exhibits sharp edges and a regular octahedral morphology. No obvious lattice fringes were observed on the UiO-66 support. Combined with the absence of PMA characteristic peaks in the XRD pattern of phosphomolybdic acid / UiO-66, it can be inferred that PMA may be distributed in an amorphous form on the UiO-66 support. Furthermore, energy-dispersive X-ray spectroscopy (EDS) shows that C, O, Zr, Mo, and P elements are uniformly distributed on the surface of the phosphomolybdic acid / UiO-66 material. Figure 5 These results indicate that PMA was successfully loaded onto the UiO-66 support while maintaining the original morphological and structural characteristics of the UiO-66 support.

[0032] XRD patterns show that the diffraction peak positions of phosphomolybdic acid / UiO-66 are basically consistent with those of the original UiO-66 support. Figure 6Characteristic diffraction peaks belonging to the (222), (011), (112), and (222) crystal planes of UiO-66 were observed at 5.6°, 6.5°, 7.3°, 10.3°, 12.7°, and 18.0°. This result indicates that the introduction of PMA did not alter the lattice structure of UiO-66, and no characteristic diffraction peaks of crystalline PMA were observed, suggesting that PMA is highly dispersed or amorphous in the UiO-66 support, further confirming that PMA is uniformly loaded on UiO-66. FTIR spectroscopy results show that ( Figure 7 ), phosphomolybdic acid / UiO-66 not only retains the characteristic absorption peak of the UiO-66 organic ligand, but also at 1045 cm⁻¹ -1 938cm -1 846cm -1 and 780cm -1 Four characteristic vibrational peaks of PMA appeared at 902 cm⁻¹, attributed to the asymmetric stretching vibrations of P-Oa, Mo=Od, Mo-Op-Mo, and Mo-Oe-Mo, respectively. These characteristic peaks showed a slight shift compared to pure PMA, attributed to interfacial bonding formed by electron transfer between PMA and the UiO-66 support. Furthermore, the phosphomolybdic acid / UiO-66 Raman spectrum showed... -1 The observation of asymmetric stretching vibration peaks attributable to Mo=O bonds further confirms the introduction of PMA, consistent with the FTIR analysis results. Figure 8 ).

[0033] Nitrogen adsorption-desorption isotherms and thermogravimetric analysis were performed on phosphomolybdic acid (PMA) / UiO-66. Both UiO-66 and phosphomolybdic acid / UiO-66 exhibited reversible type IV nitrogen adsorption isotherms, with BET specific surface areas of 1141.32 m². 2 / g and 1102.14m 2 / g, with average pore sizes of 2.31nm and 2.23nm, respectively. Figure 9 , Figure 10 Compared to UiO-66, the specific surface area, pore size, and pore volume of phosphomolybdic acid / UiO-66 decreased slightly, possibly due to the introduction of PMA occupying part of the pore space inside UiO-66. The abundant porous structure of phosphomolybdic acid / UiO-66 is beneficial for the adsorption and enrichment of reactants, thereby helping to improve the conversion efficiency of reactants. Thermogravimetric results show that the thermal decomposition behavior of UiO-66 and phosphomolybdic acid / UiO-66 is quite similar, both exhibiting two distinct weight loss stages. Figure 11The mass loss in the 25–100°C range is mainly attributed to residual volatile solvents (such as ethanol and physically adsorbed water) in the material. The slow weight loss in the 100–200°C range is due to the removal of DMF solvent molecules and the loss of coordinated water. The mass loss in the 200–500°C range can be attributed to the decomposition of terephthalic acid ligands, while the rapid decrease in mass in the 500–580°C range can be attributed to the collapse of the organic framework within the material.

[0034] Further tests were conducted on the static water contact angle, water adsorption isotherm, and CO2 adsorption isotherm to evaluate the potential value of phosphomolybdic acid / UiO-66 in the CO2 and water reaction in dielectric barrier discharge plasma. Figure 12 As shown, the static water contact angle of phosphomolybdic acid / UiO-66 nanoparticles is lower than that of the original UiO-66, indicating that the introduction of PMA improves the hydrophilicity of the material. PMA is a strongly polar heteropolyacid, rich in hydrophilic P=O and Mo=O bonds and with a large number of exposed oxygen atoms. Loading PMA onto UiO-66, these strongly polar groups greatly enhance the hydrophilicity of the UiO-66 support surface, resulting in a significant reduction in the water contact angle. The improved wettability helps the phosphomolybdic acid / UiO-66 catalytic material to more effectively capture water molecules, thereby forming a hydrogen bond network structure with PMA through hydrogen bonding, providing favorable conditions for plasma catalytic reactions. The water adsorption isotherms of UiO-66 and phosphomolybdic acid / UiO-66 show that phosphomolybdic acid / UiO-66 exhibits a higher water adsorption capacity than the original UiO-66 in the low-pressure region, while the original UiO-66 has a higher water adsorption capacity in the high-pressure region. Figure 13 This indicates that the increase in the water adsorption capacity of phosphomolybdic acid / UiO-66 is not due to an increase in specific surface area or the number of active sites, but rather to the improvement in surface hydrophilicity caused by the introduction of PMA. Phosphomylic acid / UiO-66 exhibits stronger affinity and adsorption capacity for water molecules, facilitating the rapid establishment of a water molecule layer and promoting the formation of a hydrogen bond network under low pressure conditions. This hydrogen bond network enhances the adsorption of water molecules. At higher pressures, UiO-66 shows a greater water adsorption capacity, attributed to the aggregation of water molecules primarily through physical adsorption within its pores. Furthermore, across the entire relative pressure range, phosphomolybdic acid / UiO-66 demonstrates a higher CO2 adsorption capacity than the UiO-66 support, indicating that the introduction of PMA not only improves the material's hydrophilicity but also provides more adsorption sites that can interact with CO2, thus enhancing the CO2 adsorption capacity of the metal-organic framework catalytic material. Figure 14 The improved CO2 and water adsorption properties described above indicate that phosphomolybdic acid / UiO-66 has good application potential in plasma-catalyzed CO2 and water conversion reactions, and its strong reactant adsorption capacity provides an important foundation for reactant conversion in subsequent plasma catalytic processes.

[0035] The structural characterization results of the metal-organic framework (MOF) catalytic material show that it possesses a high specific surface area and porous structure, exhibiting excellent H2O and CO2 adsorption and activation capabilities. The PMA component in the MOF catalytic material, rich in hydrophilic P=O and Mo=O bonds and with a large number of exposed oxygen atoms, significantly enhances the hydrophilicity of the catalytic material. In the reaction system where CO2 and water vapor coexist, it can effectively capture water molecules, thereby forming a hydrogen bond network structure through hydrogen bonding, promoting CO2 activation and further hydrogenation. This construction of the reaction microenvironment lays an important foundation for subsequent plasma-catalyzed CO2-water conversion reactions.

[0036] The performance of phosphomolybdic acid / UiO-66 in the co-conversion of CO2 and H2O was tested in a dielectric barrier discharge plasma-catalytic reaction system. The results showed that under conditions of 12 W input power and 20 sccm gas flow rate, a single catalyst could not drive CO2 conversion, while plasma alone achieved a CO2 conversion rate of 3.51%, indicating that plasma is the main energy source driving the reaction, capable of generating high-energy electrons and active species (such as excited-state molecules and free radicals) to activate inert CO2 and H2O molecules. Compared with UiO-66, the metal-organic framework (PMA) catalytic material significantly improved the conversion of CO2 and H2O. With increasing PMA loading, the CO2 conversion rate and H2 yield decreased slightly, possibly due to pore blockage or active site aggregation caused by excessive PMA loading. 10 The UiO-66 catalyst exhibits the best performance. Catalysts with PMA supported on UiO-66 produced more H2 and hydrocarbons. This is likely because the hydrogen bond network structure formed between PMA and water molecules further enhances the material's adsorption and activation capacity for water, providing more protons (H+) for CO2 reduction. + )source.

[0037] like Figure 15 , Figure 16 , Figure 17As shown, in the plasma-coupled metal-organic framework (MOF) catalytic system, the CO2 conversion products are mainly CO and CH4, with a small amount of C2-C3 products also generated. In contrast, the plasma-only system only produces CO and trace amounts of CH4. Since the gaseous product concentrations were manually detected by gas chromatography after collection using a gas collection bag, air interference was unavoidable during the injection process. The O2 to N2 concentration ratio detected by the TCD detector in the gas chromatography was close to 1:3, suggesting that the plasma-assisted phosphomolybdic acid / UiO-66 catalytic CO2 and H2O co-conversion system produces less O2. Therefore, the O2 yield was not further calculated in the experiment. Introducing the catalytic material into the plasma system not only improved the reactant conversion rate but also altered the reaction pathway. Compared to UiO-66, the MOF catalytic material significantly increased the concentration of C2-C3 hydrocarbons, primarily C2H6, reaching a concentration of 4790 ppm. The abundant porosity of the UiO-66 support promotes surface discharge and micro-discharge behavior during dielectric barrier discharge, enhancing the synergistic effect between plasma and catalyst. It also enhances the local enrichment of CO on the catalytic material surface, increasing the CC coupling process and thus promoting the conversion of CO2 to higher hydrocarbons such as C2–C3. Furthermore, the introduction of PMA regulates the reaction microenvironment, further promoting the coupling of carbon-containing intermediates and enhancing the directional conversion of C2–C3 hydrocarbon products such as C2H4 and C2H6.

[0038] like Figure 18 As shown, the CO2 conversion rate gradually decreases with increasing water vapor content. This is mainly because a large number of water molecules have a strong ability to capture free electrons, which leads to a decrease in electron density in the reaction system under plasma conditions, thus affecting the reaction efficiency. Figure 19 The effect of gas flow rate on CO2 conversion rate is shown. Under the condition of constant discharge power, CO2 conversion rate gradually decreases with increasing gas flow rate, reaching a maximum of 23.66% at a CO2 flow rate of 10 mL / min. Increasing the CO2 gas flow rate shortens the residence time of reactants in the medium-barrier reactor, resulting in fewer collision opportunities between CO2 molecules and active substances such as high-energy electrons and excited-state particles, thereby reducing the CO2 conversion rate.

[0039] Figure 20The effect of input power on CO2 conversion rate and energy efficiency in dielectric barrier discharge plasma (DBD) catalytic CO2 and H2O conversion reactions was shown under conditions of a gas flow rate of 20 mL / min and a water vapor content of 3.8%. As the input power increased from 10 W to 16 W, the CO2 conversion rate increased from 8% to 25%, with the highest DBD energy efficiency at an input power of 12 W. At lower input power, the increased input energy significantly enhanced the electric field strength, which facilitated the generation of more electrons. Increased collisions between electrons and CO2 molecules led to the breaking of C=O bonds and an increase in the number of active species within the reaction region, thereby promoting CO2 dissociation and hydrogenation reduction. Further increasing the discharge power from 16 W to 20 W resulted in a slight decrease in CO2 conversion rate. This is attributed to the tendency of the accumulated charge on the dielectric surface to saturate, leading to no significant change in DBD filamentary discharge, and the increase in water-gas side reactions.

[0040] In the plasma-assisted phosphomolybdic acid / UiO-66 catalytic reaction of CO2 and H2O, the main carbon-containing product is CO. Related reaction mechanism studies confirm that hydrogen from water participates in CO formation during the plasma-driven reaction, and *CO and *COOH are key intermediates in the reduction of CO2 to CO. Based on this, the Gibbs free energy change (ΔG) of the CO2 reduction process was calculated. Figure 21 In the reaction pathway of CO2 reduction to CO, the adsorbed CO2 first reacts with H+. + / e - The reaction forms a *COOH intermediate, which is then further reacted with H+. + / e - The reaction involves a proton-coupled electron transfer process to generate *CO, accompanied by the formation of water molecules. Ultimately, *CO desorbs to form CO. Gibbs free energy calculations show that the energy barrier (ΔG*COOH) for the *COOH intermediate formation step in the hydrogen bond network structure formed by PMA and water molecules is 1.86 eV, significantly lower than that of the pure PMA system (2.17 eV). This indicates that the hydrogen bond microenvironment formed by PMA and water effectively lowers the free energy barrier for CO2 reduction to *COOH, thereby accelerating the reaction kinetics of CO2 to CO conversion.

[0041] In summary, this invention constructs a high-specific-surface-area porous phosphomolybdic acid / UiO-66 plasma catalytic material by confining PMA onto a metal-organic framework UiO-66 using a solvothermal method. PMA contains a large number of exposed oxygen atoms in the CO2 and water vapor reaction system, and PMA and water vapor can form a hydrogen-bonded network structure, regulating the microenvironment of the material surface. The abundant pore structure of UiO-66 promotes surface discharge and micro-discharge behavior during dielectric barrier discharge, enhancing the synergistic effect between plasma and catalyst, and also enhances the local enrichment of CO on the catalytic material surface, promoting the CC coupling process and thus the conversion of CO2 to higher hydrocarbons such as C2–C3. Comprehensive characterization and DFT calculations show that the hydrogen-bonded microenvironment on the phosphomolybdic acid / UiO-66 surface facilitates the capture of water molecules, resulting in water molecule enrichment on the catalytic material, reducing the concentration of gaseous free water, and thus weakening the negative effect of water on the dissociation of CO2 in the plasma. Furthermore, the hydrogen-bonded microenvironment on the phosphomolybdic acid / UiO-66 surface can effectively enrich and activate reactants, significantly reducing the energy barrier of CO2→*COOH and accelerating the conversion kinetics of CO2 to CO. Under ambient temperature and pressure and a plasma input power of 12W, the phosphomolybdic acid / UiO-66 catalytic system achieved a CO2 conversion rate of 17.78%, nearly three times higher than the unmodified system. Meanwhile, using the metal-organic framework catalytic material doped with C3N5 / MXene composite powder as in Example 4, the CO2 conversion rate increased to 47.63% under the same conditions. However, using the metal-organic framework catalytic material doped with C3N5 / MXene composite powder as in Comparative Example 1, the CO2 conversion rate increased to 27.51%, slightly higher than the 17.78% of Example 1, but far lower than the 47.63% of Example 4. In Example 4, (3-aminopropyl)triethoxysilane was added as a coupling agent during the preparation of the C3N5 / MXene composite powder. This chemically bridged the layered structures of C3N5 and MXene, reducing the risk of component stripping or aggregation. Compared to Comparative Example 1 (without (3-aminopropyl)triethoxysilane), the catalyst in Example 4 maintained structural integrity better during repeated use, preventing the loss of active components. This indicates that a stable support-active site interface is crucial for ensuring the catalyst's cycle performance. The metal-organic framework catalysts prepared by Comparative Example 2 (doped solely with C3N5 powder) and Comparative Example 3 (doped solely with MXene powder) achieved CO2 conversion rates of 22.85% and 19.62%, respectively. These rates were slightly higher than in Example 1, lower than 27.51% in Comparative Example 1, and significantly lower than 47.63% in Example 4. This suggests that the composite of C3N5 and MXene powders loaded onto UiO-66 catalyzed a synergistic effect on CO2 catalytic conversion.

[0042] The number of devices and processing scale described herein are for the purpose of simplifying the description of the invention. Applications, modifications, and variations of the invention will be readily apparent to those skilled in the art.

[0043] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A method of preparing a metal organic framework catalytic material, characterized in that, The method comprises the following steps: Step one, using zirconium source, terephthalic acid to synthesize metal organic framework UiO-66; Step two, loading phosphomolybdic acid on the metal organic framework UiO-66 by a solvothermal method to obtain a metal organic framework catalytic material.

2. The method of claim 1, wherein the metal organic framework catalytic material is prepared by the steps of: In the step one, the specific method for synthesizing the metal organic framework UiO-66 by using the zirconium source and terephthalic acid comprises: S11, dissolving the zirconium source, terephthalic acid, acetic acid and deionized water in N,N-dimethylformamide to obtain a mixed solution; S12, transferring the obtained mixed solution into a polytetrafluoroethylene-lined high-pressure reaction kettle and heating for a certain time; S13, after cooling to room temperature, the obtained powder is separated by centrifugation and washed with N,N-dimethylformamide, methanol and acetone for multiple times, and then dried to obtain the metal organic framework UiO-66.

3. The method for preparing the metal-organic framework catalytic material as described in claim 2, characterized in that, In the S11, the zirconium source is zirconium tetrachloride; The amount ratio of the zirconium tetrachloride, terephthalic acid, acetic acid and deionized water, N,N-dimethylformamide is 6-7 mmol:6-7 mmol:10-15 mL:600-700 μL:40-60 mL.

4. The method for preparing the metal-organic framework catalytic material as described in claim 2, characterized in that, In the S12, the heating temperature is 110-130 ℃, and the heating time is 12-48 h.

5. The method for preparing the metal-organic framework catalytic material as described in claim 2, characterized in that, In the S13, the drying temperature is 50-80 ℃, and the drying time is 6-12 h.

6. The method of claim 1, wherein the metal organic framework catalytic material is prepared by the steps of: The specific method of the step two comprises: S21, dispersing the metal organic framework UiO-66 and phosphomolybdic acid in a mixed solution of anhydrous ethanol and deionized water to obtain a mixture; S22, transferring the mixture into a polytetrafluoroethylene-lined hydrothermal reaction kettle for a solvothermal reaction; S23, after the reaction is completed, the solid product is washed with deionized water and anhydrous ethanol, and dried at 50-80 ℃ for 6-12 h to obtain the metal organic framework catalytic material.

7. The method for preparing the metal-organic framework catalytic material as described in claim 6, characterized in that, In the S21, the amount ratio of the metal organic framework UiO-66, phosphomolybdic acid and the mixed solution is 0.06-0.07 mmol:0.005-0.02 mmol:50-100 mL; in the mixed solution, the volume ratio of anhydrous ethanol to deionized water is 1:1; In the S22, the heating temperature of the solvothermal reaction is 90-110 ℃, and the reaction time is 6-24 h.

8. The method for preparing the metal-organic framework catalytic material as described in claim 1, characterized in that, In the step two, the C3N5 / MXene composite powder accounting for 1%-10% of the mass of the phosphomolybdic acid is further doped into the metal organic framework catalytic material, and the preparation method of the C3N5 / MXene composite powder comprises: S1, mixing CuCl2 powder and Ti3SiC2 powder according to a molar ratio of 10-15:1, loading into a tube furnace, sealing, introducing argon to exhaust air in the furnace, heating to 700-800 ℃ at a rate of 5 ℃ / min, and keeping the temperature for 2-12 h; grinding the solid after the reaction into powder, washing with HCl and deionized water for multiple times, and vacuum drying at 60 ℃ for 3 h to obtain the MXene powder; S2, 3-amino-1,2,4-triazole and thiourea are mixed in a molar ratio of 3:1, calcined at 500-600℃ for 2-6h, and then the product is transferred to a reaction kettle for hydrothermal reaction at 160-180℃ for 12-24h, washed and dried to obtain C3N5 powder; S3, MXene powder and C3N5 powder are dispersed in deionized water respectively to obtain MXene dispersion and C3N5 dispersion; the MXene dispersion and the C3N5 dispersion are mixed in a volume ratio of 2-3:1, and (3-aminopropyl)triethoxysilane accounting for 1%-10% of the mass of the MXene powder is added, and the temperature is raised to 60-80℃, and stirred for 6-12h; the solid is collected by centrifugation and freeze-dried to obtain C3N5 / MXene composite powder; wherein the amount ratio of MXene to deionized water is 1g-3g:100-200mL, and the amount ratio of C3N5 to deionized water is 2-5g:100-300mL.

9. Use of a metal organic framework catalytic material prepared by the method of any one of claims 1 to 8, characterized in that, The metal organic framework catalytic material is applied to radiation activation and catalytic reduction of CO2, and under the condition of plasma radiation, CO2 and H2O are adsorbed and activated by phosphomolybdic acid / UiO-66, and CO2 and H2O are catalyzed to generate H2, CO, O2 and hydrocarbons; the hydrocarbons include CH4, C2H2, C2H4, C2H6 and C3H8.

10. Use of a metal organic framework catalytic material according to claim 9, wherein, The metal organic framework catalytic material is filled in the discharge gap of the dielectric barrier discharge plasma reactor, and is fixed by quartz wool at both ends of the dielectric barrier discharge plasma reactor, and then H2O-moistened CO2 gas is introduced into the dielectric barrier discharge plasma reactor at a flow rate of 10-40mL / min; by adjusting the voltage and current of the plasma experimental power supply, the input power is changed, and before each discharge, the moistened CO2 gas is introduced to purge for a certain time, and H2O and CO2 are catalyzed to generate H2, CO, O2 and hydrocarbons; The structure of the dielectric barrier discharge plasma reactor comprises: an outer quartz tube wrapped with aluminum foil, one end of the outer quartz tube is provided with a gas inlet, and the other end of the outer quartz tube is provided with a product outlet; the outer quartz tube is connected to the ground electrode of the plasma power supply; the two ends of the outer quartz tube are sealed by polytetrafluoroethylene joints; an inner quartz tube placed inside the outer quartz tube along the axis, the inner quartz tube is provided with a stainless steel rod inside, and the stainless steel rod is connected to the high-voltage electrode of the plasma power supply; the discharge gap is located between the outer quartz tube and the inner quartz tube.

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