Ternary metal oxide-molecular sieve composite material for catalyzing CO2 hydrogenation to prepare low-carbon alkane as well as preparation method and application of ternary metal oxide-molecular sieve composite material

Abstract

The invention discloses a ternary metal oxide-molecular sieve composite material as well as a preparation method and application thereof, and relates to the technical field of catalysts. The composite material provided by the invention comprises a ternary metal oxide and a molecular sieve, the general formula of the ternary metal oxide is M1aM2bM3cOx, M1 is at least one of Fe, Co, Ni, Pt, Pd, Cu and Zn, M2 is at least one of Cr, Mn, Mo, Cd, Ga and In, M3 is at least one of Ce, Zr, Ti and Al, and the molar ratio of a: b: c is (0.01-0.5): (0.05-1): 1. The optimized ternary metal and the molecular sieve are used as the composite catalyst, so that the CO2 conversion rate is increased and the stability of the catalyst is remarkably improved at a relatively low catalytic temperature; the H-SAPO-34 molecular sieve has an eight-membered ring orifice structure and is beneficial to the generation of low-carbon olefins, and meanwhile, the high-efficiency conversion of the low-carbon olefins into C2-C4 alkanes (ethane, propane and butane) is promoted due to the relatively high hydrogenation capacity of oxides.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial catalysis, and in particular to a ternary metal oxide-molecular sieve composite material, a preparation method thereof, and an application thereof in the reaction of CO2 hydrogenation to produce light alkanes. Background Art

[0002] With the development of industry, human activities such as the massive burning of fossil fuels have led to a dramatic increase in atmospheric CO2 levels, resulting in a series of environmental problems such as the severe greenhouse effect and global warming. Therefore, reducing CO2 emissions and effectively utilizing them has become a global focus. CO2 is also an abundant, inexpensive, and renewable carbon resource. Hydrogenating CO2 into hydrocarbons such as low-carbon alkanes allows for resourceful utilization of CO2, providing a new pathway for producing high-value-added chemicals and fuels. This also helps alleviate dependence on traditional fossil fuels and address the increasingly prominent energy shortage issue.

[0003] Traditional methods for producing alkanes primarily involve petroleum refining, coal liquefaction, and biomass conversion. These methods present challenges such as difficulty in obtaining or collecting raw materials, high energy consumption, high investment costs, and significant carbon emissions. CO2 hydrogenation to alkane technology utilizes H2 generated by water electrolysis from renewable energy sources to react with CO2, storing the renewable energy as chemical energy in alkanes. This energy storage and conversion is of great significance to building a sustainable energy system.

[0004] Existing CO2 hydrogenation catalysts generally suffer from low conversion (<25%), alkane selectivity limited by the Anderson-Schultz-Flory rule (<50%), and sintering at high temperatures. For example, Fe-based catalysts tend to generate CO as a byproduct at temperatures above 350°C, while traditional Co-based catalysts have insufficient selectivity for C2-C4 alkanes. In 2016, Bao Xinhe's team proposed the design concept of a nanocomposite bifunctional OXZEO catalyst coupled with a metal oxide and a molecular sieve. Science, 351, 1065-1068 (2016)), which effectively separated the two key steps of CO activation and carbon-carbon bond coupling in the synthesis gas conversion reaction, broke through the insurmountable Anderson-Schultz-Flory (ASF) limit of the Fischer-Tropsch synthesis product distribution from the catalytic principle, and achieved the highly selective generation of C2 = -C4 =Light olefins, and subsequently, the OXZEO system, will be gradually applied to CO2 hydrogenation to produce alkanes. Traditional alkane production methods, while mature, suffer from high energy consumption and significant greenhouse gas emissions, particularly CO2. The OXZEO system combines CO2 as an abundant feedstock with increasingly mature green hydrogen production technologies to efficiently synthesize light alkanes (ethane, propane, and butane). However, this system also suffers from issues such as insufficient activation of CO2 by oxides and poor stability. For example, the GaZrOx / H-SSZ-13 composite catalyst, disclosed in 2022, showed significant deactivation after 100 hours of operation in the CO2 hydrogenation to alkanes reaction (Nature Catal., 5, 1038–1050 (2022)). Summary of the Invention

[0005] The purpose of the present invention is to provide a ternary metal oxide-molecular sieve composite material for catalyzing CO2 hydrogenation to produce light alkanes, as well as its preparation method and application. The ternary metal oxide-molecular sieve composite material provided by the present invention can significantly improve the conversion rate of CO2 and effectively improve the stability of the catalyst when catalyzing CO2 hydrogenation to produce C2-C4 alkanes, while also significantly improving the selectivity of C2-C4 alkanes.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions: The present invention provides a ternary metal oxide-molecular sieve composite material for catalyzing CO2 hydrogenation to prepare light alkanes, comprising a ternary metal oxide and a molecular sieve with optimized structure and components: the ternary metal oxide has the general formula M1 a M2 b M3 c Ox, wherein M1 is at least one of Fe, Co, Ni, Pt, Pd, Cu, and Zn, M2 is at least one of Cr, Mn, Mo, Cd, Ga, and In, and M3 is at least one of Ce, Zr, Ti, and Al, and the molar ratio a:b:c is 0.01-0.5: 0.05-1: 1. The molecular sieve is one of the acidic H-SAPO-34, H-SAPO-18, H-RUB-13, and H-SZZ-13 molecular sieves.

[0007] Preferably, M1 is one of Fe, Co, Ni, Pt, Pd, Cu, and Zn; Preferably, M2 is one of Cr, Mn, Mo, Cd, Ga, and In; Preferably, M3 is one of Ce, Zr, Ti, and Al; Preferably, the molar ratio a:b:c=0.01-0.5: 0.05-1: 1; Preferably, the molecular sieve is one of acidic H-SAPO-34, H-SAPO-18, H-RUB-13, and H-SZZ-13; Preferably, the molecular sieve has a silicon to aluminum atomic ratio of 0.025 to 200:1; Preferably, the mass ratio of the ternary metal oxide to the molecular sieve is 1:0.1-10.

[0008] The present invention provides a method for preparing the ternary metal oxide-molecular sieve composite material described in the above technical solution, comprising the following steps: (1) Mixing a soluble metal salt and a solvent to obtain a metal ion solution; the soluble metal salt is a water-soluble M1, M2, M3 metal salt or a soluble organic M1, M2, M3 metal salt; (2) mixing a complexing agent with a solvent to obtain a complexing agent solution; the complexing agent is a precipitant or a complexing agent; (3) slowly adding the above-mentioned composite agent solution dropwise to the above-mentioned metal salt solution to prepare a ternary metal oxide solid precursor; (4) aging, washing, drying, and calcining the ternary metal oxide solid precursor to obtain a ternary metal oxide; (5) mixing the ternary metal oxide and acid to obtain a ternary metal oxide-molecular sieve composite material; The step (3) is any one of steps (3.1) to (3.2): (3.1): Dissolve the metal salt and precipitant in water respectively, add the precipitant aqueous solution dropwise to the metal salt aqueous solution to carry out precipitation reaction, and obtain a ternary metal oxide solid precursor; (3.2): Dissolve the metal salt and complexing agent in an organic solvent respectively, add the complexing agent solution dropwise to the metal salt solution to carry out a complexation reaction to obtain a ternary metal oxide solid precursor; Preferably, the precipitant comprises one or more of water-soluble carbonates, water-soluble bicarbonates and water-soluble hydroxides; Preferably, the complexing agent comprises one or more of glucose, citric acid, tartaric acid, salicylic acid, oxalic acid and adipic acid; Preferably, the organic solvent is any one of methanol, ethanol, propylene glycol, ethylene glycol, and n-propanol; Preferably, the molar ratio of total metal ions to complexing agent in the solution is 1:0.5-5; Preferably, the molar ratio of the solvent to the metal ion is 500 to 3500:1; Preferably, the molar ratio of the solvent to the complexing agent is 500 to 3500:1; Preferably, the temperature of the precipitation and complexation reaction is 60 to 150°C; Preferably, the aging time of the precipitation and complexation reaction is 3 to 20 hours; Preferably, the drying temperature is 50-150°C; Preferably, the calcination temperature is 350-700°C; Preferably, the holding time of the roasting treatment is 2 to 10 hours; Preferably, the pressure in the catalytic reaction conditions is 0.1 to 6 MPa; Preferably, the temperature in the catalytic reaction conditions is 250-420°C; Preferably, the catalytic reaction conditions are a space velocity of 500 to 40,000 mL g cat -1 h -1 ; Preferably, the H2 / CO2 ratio in the catalytic reaction conditions is 1 / 1 to 1 / 12.

[0009] The present invention provides the use of the ternary metal oxide-molecular sieve composite material described in the above technical solution or the ternary metal oxide-molecular sieve composite material prepared by the preparation method described in the above technical solution in catalyzing CO2 hydrogenation to produce light alkanes (ethane, propane and butane).

[0010] Beneficial effects: In the present invention, CO2 and H2 are converted into CH3OH on the ternary metal oxide, and then the molecular sieve converts CH3OH into light olefins, and the light olefins are further efficiently converted into C2-C4 alkanes on the oxide surface. C2-C4 alkanes refer to ethane, propane and butane. In the preparation of C2-C4 alkanes, ethane, propane and butane products may all be produced at the same time.

[0011] The present invention uses ternary metal oxides and acidic molecular sieves as co-catalysts for the preparation of C2-C4 alkanes by CO2 hydrogenation, which can significantly improve the conversion rate of CO2, while also significantly enhancing the selectivity of C2-C4 alkanes and effectively improving the stability of the catalyst.

[0012] The ternary metal oxide is activated by CO2 adsorption to generate a methanol intermediate. The ternary metal oxide, after structural and component optimization, can significantly improve the CO2 conversion rate. At the same time, there is a strong metal interaction between the optimized metal ratio and metal composition, which effectively inhibits the migration of active metals, effectively maintains the active sites and prolongs the catalyst life. The suitable ring and pore structure and suitable acidic properties of the acidic molecular sieve are conducive to the high selectivity of methanol to olefins. Olefins are over-hydrogenated to alkanes at the active sites of the ternary metal oxide, further promoting the forward shift of the CO2 hydrogenation reaction and increasing the CO2 conversion rate. The results of the examples show that when the ternary metal oxide-molecular sieve composite material provided by the present invention is used as a catalyst in the reaction of CO2 hydrogenation to produce C2-C4 alkanes, the CO2 conversion rate can reach 38%, the CO selectivity is 40%, and the C2-C4 alkane selectivity is 81%, and the catalyst life is up to 100 hours or more.

[0013] In the present invention, the activity of the catalyst for CO2 hydrogenation reaction is evaluated by the volume change coefficient ηN2, CO2 conversion rate CO selectivity, and light alkane selectivity indicators:

[0014]

[0015] Where n represents the number of carbon atoms, and m represents 2n, 2n+2 (olefins and alkanes in the product).

[0016] The present invention also provides a method for preparing the ternary metal oxide-molecular sieve composite material described in the above technical solution. The preparation method provided by the present invention is simple to operate and low in cost, and is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 :Catalyst Ni 0.075 Cd 0.2 ZrOx and Cd 0.2 XRD pattern of ZrOx; Figure 2 :Catalyst Ni 0.075 Cd 0.2 ZrOx and Cd 0.2 CO2-TPD diagram of ZrOx; Figure 3 :Catalyst Ni 0.075 Cd 0.2 ZrOx and Cd 0.2 C3H6 conversion diagram of C3H6 hydrogenation reaction of ZrOx; Figure 4 :Mechanism diagram of ternary metal oxide-molecular sieve composite materials for CO2 hydrogenation to alkanes; Figure 5: Gas chromatography spectrum of product distribution of ternary metal oxide-molecular sieve composite material used for CO2 hydrogenation to produce alkanes in Example 7. DETAILED DESCRIPTION

[0018] The technical solution of the present invention is described below through specific examples. It should be understood that the one or more method steps mentioned in the present invention do not exclude the presence of other method steps before and after the combination step or the insertion of other method steps between these explicitly mentioned steps; it should also be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or to define the scope of the present invention. Changes or adjustments in their relative relationships, without substantially changing the technical content, should also be regarded as the scope of the present invention.

[0019] Example 1: Preparation of Zn 0.05 Cd 0.1 TiOx / SAPO-34 composite materials and their applications: 1. Dissolve Zn(NO3)2·6H2O, Cd(NO3)2·4H2O, and tetrabutyl titanate in anhydrous ethanol at a molar ratio of 0.05:0.1:1 to prepare a 0.02 mol / L metal salt solution; 2. Dissolve citric acid in anhydrous ethanol to prepare a 0.03 mol / L solution; 3. Quickly add the above two solutions to the first solution and react in a 45°C water bath for 24 hours. 4. The solution in 3 was centrifuged, dried at 80℃, and calcined at 500℃ for 3 h to obtain Zn 0.05 Cd 0.1 TiOx oxide; 5. Zn 0.05 Cd 0.1 TiOx oxide and SAPO-34 molecular sieve with a silicon-aluminum atomic ratio of 0.075 were physically mixed at a mass ratio of 1:2 and crushed to 20-40 mesh to obtain Zn 0.05 Cd 0.1 TiOx / SAPO-34(0.075) tandem catalyst 6. At 350℃, 3 MPa, GHSV=1000 h -1 After 14 hours of reaction under the conditions of H2 / CO2=6, samples were taken for analysis, and the reaction products were detected online by gas chromatography. The reaction results are shown in Table 1.

[0020] Example 2: Preparation of Zn 0.1 Cd 0.1TiOx / SAPO-34 composite materials and their applications: 1. Dissolve Zn(NO3)2·6H2O, Cd(NO3)2·4H2O, and tetrabutyl titanate in anhydrous ethanol at a molar ratio of 0.1:0.1:1 to prepare a 0.02 mol / L metal salt solution; 2. Dissolve citric acid in anhydrous ethanol to prepare a 0.03 mol / L solution; 3. Quickly add the above two solutions to the first solution and react in a 45°C water bath for 24 hours. 4. The solution in 3 was centrifuged, dried at 80℃, and calcined at 500℃ for 3 h to obtain Zn 0.1 Cd 0.1 TiOx oxide; 5. Zn 0.1 Cd 0.1 TiOx oxide and SAPO-34 molecular sieve with a silicon-aluminum atomic ratio of 0.075 were physically mixed at a mass ratio of 1:2 and crushed to 20-40 mesh to obtain Zn 0.1 Cd 0.1 TiOx / SAPO-34(0.075) tandem catalyst 6. At 350℃, 3 MPa, GHSV=1000 h -1 After 14 hours of reaction under the conditions of H2 / CO2=6, samples were taken for analysis, and the reaction products were detected online by gas chromatography. The reaction results are shown in Table 1.

[0021] Example 3: Preparation of Zn 0.2 Cd 0.1 TiOx / SAPO-34 composite materials and their applications: 1. Dissolve Zn(NO3)2·6H2O, Cd(NO3)2·4H2O, and tetrabutyl titanate in anhydrous ethanol at a molar ratio of 0.2:0.1:1 to prepare a 0.02 mol / L metal salt solution; 2. Dissolve citric acid in anhydrous ethanol to prepare a 0.03 mol / L solution; 3. Quickly add the above two solutions to the first solution and react in a 45°C water bath for 24 hours. 4. The solution in 3 was centrifuged, dried at 80℃, and calcined at 500℃ for 3 h to obtain Zn 0.2 Cd 0.1 TiOx oxide; 5. Zn 0.2 Cd 0.1 TiOx oxide and SAPO-34 molecular sieve with a silicon-aluminum atomic ratio of 0.075 were physically mixed at a mass ratio of 1:2 and crushed to 20-40 mesh to obtain Zn 0.2 Cd0.1 TiOx / SAPO-34(0.075) tandem catalyst 6. At 350℃, 3 MPa, GHSV=1000 h -1 After 14 hours of reaction under the conditions of H2 / CO2=6, samples were taken for analysis, and the reaction products were detected online by gas chromatography. The reaction results are shown in Table 1.

[0022] Example 4: Preparation of Ni 0.1 Mn 0.2 ZrOx / SAPO-34 composite materials and their applications: 1. Dissolve Ni(NO3)2·6H2O, Mn(NO3)2·4H2O, and Zr(NO3)4·5H2O in 200 ml of deionized water at a molar ratio of 0.1:0.2:1 to prepare a 0.02 mol / L metal salt solution; 2. Dissolve ammonium carbonate in 200 ml of deionized water to prepare a 0.03 mol / L solution. 3. Quickly add the above two solutions to the first solution and react in a 70℃ water bath for 2 hours (pH = 7). 4. The solution in 3 was centrifuged, dried at 110℃, and calcined at 500℃ for 3 h to obtain Ni 0.1 Mn 0.2 ZrOx oxide; 5. 0.1 Mn 0.2 ZrOx oxide and SAPO-34 molecular sieve with a silicon-aluminum atomic ratio of 0.075 were physically mixed at a mass ratio of 1:2 and crushed to 20-40 mesh to obtain Ni 0.1 Mn 0.2 ZrOx / SAPO-34(0.075) tandem catalyst 6. At 350℃, 2 MPa, GHSV=1000 h -1 After 14 hours of reaction under the conditions of H2 / CO2=6, samples were taken for analysis, and the reaction products were detected online by gas chromatography. The reaction results are shown in Table 1.

[0023] Example 5: Preparation of Ni 0.1 Mn 0.2 ZrOx / SAPO-34 composite oxide and its application: 1. Dissolve Ni(NO3)2·6H2O, Mn(NO3)2·4H2O, and Zr(NO3)4·5H2O in 200 ml of deionized water at a molar ratio of 0.1:0.2:1 to prepare a 0.02 mol / L metal salt solution; 2. Dissolve ammonium carbonate in 200 ml of deionized water to prepare a 0.03 mol / L solution. 3. Quickly add the above two solutions to the first solution and react in a 70℃ water bath for 2 hours (pH = 7). 4. The solution in 3 was centrifuged, dried at 110℃, and calcined at 500℃ for 3 h to obtain Ni 0.1 Mn 0.2 ZrOx oxide; 5. 0.1 Mn 0.2 ZrOx oxide and SAPO-34 molecular sieve with a silicon-aluminum atomic ratio of 0.075 were physically mixed at a mass ratio of 1:2 and crushed to 20-40 mesh to obtain Ni 0.1 Mn 0.2 ZrOx / SAPO-34(0.075) tandem catalyst 6. At 350℃, 3 MPa, GHSV=1000 h -1 After 14 hours of reaction under the conditions of H2 / CO2=6, samples were taken for analysis, and the reaction products were detected online by gas chromatography. The reaction results are shown in Table 1.

[0024] Example 6: Preparation of Ni 0.1 Mn 0.2 ZrOx / SAPO-34 composite materials and their applications: 1. Dissolve Ni(NO3)2·6H2O, Mn(NO3)2·4H2O, and Zr(NO3)4·5H2O in 200 ml of deionized water at a molar ratio of 0.1:0.2:1 to prepare a 0.02 mol / L metal salt solution; 2. Dissolve ammonium carbonate in 200 ml of deionized water to prepare a 0.03 mol / L solution. 3. Quickly add the above two solutions to the first solution and react in a 70℃ water bath for 2 hours (pH = 7). 4. The solution in 3 was centrifuged, dried at 110℃, and calcined at 500℃ for 3 h to obtain Ni 0.1 Mn 0.2 ZrOx oxide; 5. 0.1 Mn 0.2 ZrOx oxide and SAPO-34 molecular sieve with a silicon-aluminum atomic ratio of 0.075 were physically mixed at a mass ratio of 1:2 and crushed to 20-40 mesh to obtain Ni 0.1 Mn 0.2 ZrOx / SAPO-34(0.075) tandem catalyst 6. At 350℃, 4 MPa, GHSV=1000 h -1After 14 hours of reaction under the conditions of H2 / CO2=6, samples were taken for analysis, and the reaction products were detected online by gas chromatography. The reaction results are shown in Table 1.

[0025] Example 7: Preparation of Ni 0.075 Cd 0.2 ZrOx / SAPO-34 composite materials and their applications: 1. Dissolve Ni(NO3)2·6H2O, Cd(NO3)2·4H2O, and Zr(NO3)4·5H2O in 200 ml of deionized water at a molar ratio of 0.075:0.2:1 to prepare a 0.02 mol / L metal salt solution. 2. Dissolve ammonium carbonate in 200 ml of deionized water to prepare a 0.03 mol / L solution. 3. Quickly add the above two solutions to the first solution and react in a 70℃ water bath for 2 hours (pH = 7). 4. The solution in 3 was centrifuged, dried at 110℃, and calcined at 500℃ for 3 h to obtain Ni 0.075 Cd 0.2 ZrOx oxide; 5. 0.075 Cd 0.2 ZrOx oxide and SAPO-34 molecular sieve with a silicon-aluminum atomic ratio of 0.075 were physically mixed at a mass ratio of 1:2 and crushed to 20-40 mesh to obtain Ni 0.075 Cd 0.2 ZrOx / SAPO-34(0.075) tandem catalyst 6. At 350℃, 3 MPa, GHSV=1000 h -1 After 14 hours of reaction under the conditions of H2 / CO2=6, samples were taken for analysis, and the reaction products were detected online by gas chromatography. The reaction results are shown in Table 1.

[0026] Obtained Ni 0.075 Cd 0.2 The XRD pattern of ZrOx oxide is as follows Figure 1 As shown, the main oxide phase is t-ZrO2 phase accompanied by some CdO characteristic peaks; Obtained Ni 0.075 Cd 0.2 The CO2-TPD pattern of ZrOx oxide is shown in Figure 2 Ni 0.075 Cd 0.2 ZrOx oxide has CO2 desorption peaks in the middle, low and high temperature regions, indicating that the catalyst has a strong adsorption capacity for CO2 and is better than the comparative catalyst Cd 0.2 ZrOx oxide has stronger adsorption capacity; Figure 5This is the gas chromatography product distribution diagram of Example 7. From the spectrum, it can be seen that the products are mainly C2-C4 alkanes and a small amount of olefins, further proving that the C2-C4 alkanes in the products obtained by coupling the ternary metal oxide with the molecular sieve and applying it to CO2 hydrogenation in this embodiment have high selectivity.

[0027] Example 8: Preparation of Ni 0.075 Cd 0.2 ZrOx / SAPO-34 composite materials and their applications: 1. Dissolve Ni(NO3)2·6H2O, Cd(NO3)2·4H2O, and Zr(NO3)4·5H2O in 200 ml of deionized water at a molar ratio of 0.075:0.2:1 to prepare a 0.02 mol / L metal salt solution; 2. Dissolve ammonium carbonate in 200 ml of deionized water to prepare a 0.03 mol / L solution. 3. Quickly add the above two solutions to the first solution and react in a 70℃ water bath for 2 hours (pH = 7). 4. The solution in 3 was centrifuged, dried at 110℃, and calcined at 500℃ for 3 h to obtain Ni 0.075 Cd 0.2 ZrOx oxide; 5. 0.075 Cd 0.2 ZrOx oxide and SAPO-34 molecular sieve with a silicon-aluminum atomic ratio of 0.075 were physically mixed at a mass ratio of 1:2 and crushed to 20-40 mesh to obtain Ni 0.075 Cd 0.2 ZrOx / SAPO-34(0.075) tandem catalyst 6. At 350℃, 3 MPa, GHSV=3000 h -1 After 14 hours of reaction under the conditions of H2 / CO2=6, samples were taken for analysis, and the reaction products were detected online by gas chromatography. The reaction results are shown in Table 1.

[0028] Example 9: Preparation of Ni 0.075 Cd 0.2 ZrOx / SAPO-34 composite materials and their applications: 1. Dissolve Ni(NO3)2·6H2O, Cd(NO3)2·4H2O, and Zr(NO3)4·5H2O in 200 ml of deionized water at a molar ratio of 0.075:0.2:1 to prepare a 0.02 mol / L metal salt solution; 2. Dissolve ammonium carbonate in 200 ml of deionized water to prepare a 0.03 mol / L solution. 3. Quickly add the above two solutions to the first solution and react in a 70℃ water bath for 2 hours (pH = 7). 4. The solution in 3 was centrifuged, dried at 110℃, and calcined at 500℃ for 3 h to obtain Ni 0.075 Cd 0.2 ZrOx oxide; 5. 0.075 Cd 0.2 ZrOx oxide and SAPO-34 molecular sieve with a silicon-aluminum atomic ratio of 0.075 were physically mixed at a mass ratio of 1:2 and crushed to 20-40 mesh to obtain Ni 0.075 Cd 0.2 ZrOx / SAPO-34(0.075) tandem catalyst 6. At 350℃, 3 MPa, GHSV=6000 h -1 After 14 hours of reaction under the conditions of H2 / CO2=6, samples were taken for analysis, and the reaction products were detected online by gas chromatography. The reaction results are shown in Table 1.

[0029] Example 10: Preparation of Ni 0.075 Cd 0.2 ZrOx / SAPO-34 composite materials and their applications: 1. Dissolve Ni(NO3)2·6H2O, Cd(NO3)2·4H2O, and Zr(NO3)4·5H2O in 200 ml of deionized water at a molar ratio of 0.075:0.2:1 to prepare a 0.02 mol / L metal salt solution; 2. Dissolve ammonium carbonate in 200 ml of deionized water to prepare a 0.03 mol / L solution. 3. Quickly add the above two solutions to the first solution and react in a 70℃ water bath for 2 hours (pH = 7). 4. The solution in 3 was centrifuged, dried at 110℃, and calcined at 500℃ for 3 h to obtain Ni 0.075 Cd 0.2 ZrOx oxide; 5. 0.075 Cd 0.2 ZrOx oxide and SAPO-34 molecular sieve with a silicon-aluminum atomic ratio of 0.075 were physically mixed at a mass ratio of 1:2 and crushed to 20-40 mesh to obtain Ni 0.075 Cd 0.2 ZrOx / SAPO-34(0.075) tandem catalyst 6. At 350℃, 3 MPa, GHSV=9000 h -1 After 14 hours of reaction under the conditions of H2 / CO2=6, samples were taken for analysis, and the reaction products were detected online by gas chromatography. The reaction results are shown in Table 1.

[0030] Example 11: Preparation of Ni 0.075 Cd 0.2 ZrOx / SAPO-34 composite materials and their applications: 1. Dissolve Ni(NO3)2·6H2O, Cd(NO3)2·4H2O, and Zr(NO3)4·5H2O in 200 ml of deionized water at a molar ratio of 0.075:0.2:1 to prepare a 0.02 mol / L metal salt solution; 2. Dissolve ammonium carbonate in 200 ml of deionized water to prepare a 0.03 mol / L solution. 3. Quickly add the above two solutions to the first solution and react in a 70℃ water bath for 2 hours (pH = 7). 4. The solution in 3 was centrifuged, dried at 110℃, and calcined at 500℃ for 3 h to obtain Ni 0.075 Cd 0.2 ZrOx oxide; 5. 0.075 Cd 0.2 ZrOx oxide and SAPO-34 molecular sieve with a silicon-aluminum atomic ratio of 0.075 were physically mixed at a mass ratio of 1:2 and crushed to 20-40 mesh to obtain Ni 0.075 Cd 0.2 ZrOx / SAPO-34(0.075) tandem catalyst; 6. At 350℃, 3 MPa, GHSV=1000 h -1 After 14 hours of reaction under the conditions of H2 / CO2=3, samples were taken for analysis, and the reaction products were detected online by gas chromatography. The reaction results are shown in Table 1.

[0031] Example 12: Preparation of Ni 0.075 Cd 0.2 ZrOx / SAPO-34 composite materials and their applications: 1. Dissolve Ni(NO3)2·6H2O, Cd(NO3)2·4H2O, and Zr(NO3)4·5H2O in 200 ml of deionized water at a molar ratio of 0.075:0.2:1 to prepare a 0.02 mol / L metal salt solution; 2. Dissolve ammonium carbonate in 200 ml of deionized water to prepare a 0.03 mol / L solution. 3. Quickly add the above two solutions to the first solution and react in a 70℃ water bath for 2 hours (pH = 7). 4. The solution in 3 was centrifuged, dried at 110℃, and calcined at 500℃ for 3 h to obtain Ni 0.075 Cd0.2 ZrOx oxide; 5. 0.075 Cd 0.2 ZrOx oxide and SAPO-34 molecular sieve with a silicon-aluminum atomic ratio of 0.075 were physically mixed at a mass ratio of 1:2 and crushed to 20-40 mesh to obtain Ni 0.075 Cd 0.2 ZrOx / SAPO-34(0.075) tandem catalyst 6. At 350℃, 3 MPa, GHSV=1000 h -1 After 14 hours of reaction under the conditions of H2 / CO2=4, samples were taken for analysis, and the reaction products were detected online by gas chromatography. The reaction results are shown in Table 1.

[0032] Example 13: Preparation of Ni 0.075 Cd 0.2 ZrOx / SAPO-34 composite materials and their applications: 1. Dissolve Ni(NO3)2·6H2O, Cd(NO3)2·4H2O, and Zr(NO3)4·5H2O in 200 ml of deionized water at a molar ratio of 0.075:0.2:1 to prepare a 0.02 mol / L metal salt solution; 2. Dissolve ammonium carbonate in 200 ml of deionized water to prepare a 0.03 mol / L solution. 3. Quickly add the above two solutions to the first solution and react in a 70℃ water bath for 2 hours (pH = 7). 4. The solution in 3 was centrifuged, dried at 110℃, and calcined at 500℃ for 3 h to obtain Ni 0.075 Cd 0.2 ZrOx oxide; 5. 0.075 Cd 0.2 ZrOx oxide and SAPO-34 molecular sieve with a silicon-aluminum atomic ratio of 0.075 were physically mixed at a mass ratio of 1:2 and crushed to 20-40 mesh to obtain Ni 0.075 Cd 0.2 ZrOx / SAPO-34(0.075) tandem catalyst 6. At 350℃, 3 MPa, GHSV=1000 h -1 After 14 hours of reaction under the conditions of H2 / CO2=5, samples were taken for analysis. The reaction products were detected online by gas chromatography. The reaction results are shown in Table 1.

[0033] Example 14: Preparation of Ni 0.075 Cd 0.2 ZrOx / SAPO-34 composite materials and their applications: 1. Dissolve Ni(NO3)2·6H2O, Cd(NO3)2·4H2O, and Zr(NO3)4·5H2O in 200 ml of deionized water at a molar ratio of 0.075:0.2:1 to prepare a 0.02 mol / L metal salt solution; 2. Dissolve ammonium carbonate in 200 ml of deionized water to prepare a 0.03 mol / L solution. 3. Quickly add the above two solutions to the first solution and react in a 70℃ water bath for 2 hours (pH = 7). 4. The solution in 3 was centrifuged, dried at 110℃, and calcined at 500℃ for 3 h to obtain Ni 0.075 Cd 0.2 ZrOx oxide; 5. 0.075 Cd 0.2 ZrOx oxide and SAPO-34 molecular sieve with a silicon-aluminum atomic ratio of 0.15 were physically mixed at a mass ratio of 1:2 and crushed to 20-40 mesh to obtain Ni 0.075 Cd 0.2 ZrOx / SAPO-34(0.15) tandem catalyst 6. At 350℃, 3 MPa, GHSV=1000 h -1 After 14 hours of reaction under the conditions of H2 / CO2=5, samples were taken for analysis. The reaction products were detected online by gas chromatography. The reaction results are shown in Table 1.

[0034] Example 15: Preparation of Ni 0.075 Cd 0.2 ZrOx / SAPO-34 composite materials and their applications: 1. Dissolve Ni(NO3)2·6H2O, Cd(NO3)2·4H2O, and Zr(NO3)4·5H2O in 200 ml of deionized water at a molar ratio of 0.075:0.2:1 to prepare a 0.02 mol / L metal salt solution; 2. Dissolve ammonium carbonate in 200 ml of deionized water to prepare a 0.03 mol / L solution. 3. Quickly add the above two solutions to the first solution and react in a 70℃ water bath for 2 hours (pH = 7). 4. The solution in 3 was centrifuged, dried at 110℃, and calcined at 500℃ for 3 h to obtain Ni 0.075 Cd 0.2 ZrOx oxide; 5. 0.075 Cd 0.2ZrOx oxide and SAPO-34 molecular sieve with a silicon-aluminum atomic ratio of 0.3 were physically mixed at a mass ratio of 1:2 and crushed to 20-40 mesh to obtain Ni 0.075 Cd 0.2 ZrOx / SAPO-34(0.3) tandem catalyst 6. At 350℃, 3 MPa, GHSV=1000 h -1 After 14 hours of reaction under the conditions of H2 / CO2=5, samples were taken for analysis. The reaction products were detected online by gas chromatography. The reaction results are shown in Table 1.

[0035] Example 16: Preparation of Ni 0.075 Mn 0.2 CeOx / SAPO-34 composite materials and their applications: 1. Dissolve Ni(NO3)2·6H2O, Mn(NO3)2·4H2O, and Ce(NO3)3·6H2O in 200 ml of deionized water at a molar ratio of 0.075:0.2:1 to prepare a 0.02 mol / L metal salt solution; 2. Dissolve ammonium carbonate in 200 ml of deionized water to prepare a 0.03 mol / L solution. 3. Quickly add the above two solutions to the first solution and react in a 70℃ water bath for 2 hours (pH = 7). 4. The solution in 3 was centrifuged, dried at 110℃, and calcined at 500℃ for 3 h to obtain Ni 0.075 Mn 0.2 CeOx oxide; 5. 0.075 Mn 0.2 CeOx oxide and SAPO-34 molecular sieve with a silicon-aluminum atomic ratio of 0.075 were physically mixed at a mass ratio of 1:2 and crushed to 20-40 mesh to obtain Ni 0.075 Mn 0.2 CeOx / SAPO-34(0.075) tandem catalyst 6. At 350℃, 3 MPa, GHSV=1000 h -1 After 14 hours of reaction under the conditions of H2 / CO2=6, samples were taken for analysis, and the reaction products were detected online by gas chromatography. The reaction results are shown in Table 1.

[0036] Comparative Example 1: Preparation of Cd 0.2 ZrOx / SAPO-34 composite materials and their applications: 1. Dissolve Cd(NO3)2·4H2O and Zr(NO3)4·5H2O in 200ml of deionized water at a molar ratio of 0.2:1 to prepare a 0.02mol / L metal salt solution; 2. Dissolve ammonium carbonate in 200 ml of deionized water to prepare a 0.03 mol / L solution. 3. Quickly add the above two solutions to the first solution and react in a 70℃ water bath for 2 hours (pH = 7). 4. The solution in 3 was centrifuged, dried at 110℃, and calcined at 500℃ for 3 h to obtain Cd 0.2 ZrOx oxide; 5. Will Cd 0.2 ZrOx oxide and SAPO-34 molecular sieve with a silicon-aluminum atomic ratio of 0.075 were physically mixed at a mass ratio of 1:2 and crushed to 20-40 mesh to obtain Cd 0.2 ZrOx / SAPO-34(0.075) tandem catalyst; Earned Cd 0.2 The XRD pattern of ZrOx oxide is as follows Figure 1 As shown, the main oxide phase is t-ZrO2 phase accompanied by some CdO characteristic peaks; Earned Cd 0.2 The CO2-TPD pattern of ZrOx oxide is shown in Figure 2 Shown Cd 0.2 ZrOx oxide has CO2 desorption peaks in the middle, low and high temperature regions, indicating that the catalyst has a strong adsorption capacity for CO2; At 350℃, 3 MPa, GHSV=1000 h -1 After 14 hours of reaction under the conditions of H2 / CO2=6, samples were taken for analysis, and the reaction products were detected online by gas chromatography. The reaction results are shown in Table 1.

[0037] Comparative Example 2: Preparation of Mn 0.2 ZrOx / SAPO-34 composite materials and their applications: 1. Dissolve Mn(NO3)2·4H2O and Zr(NO3)4·5H2O in 200ml of deionized water at a molar ratio of 0.2:1 to prepare a 0.02mol / L metal salt solution; 2. Dissolve ammonium carbonate in 200 ml of deionized water to prepare a 0.03 mol / L solution. 3. Quickly add the above two solutions to the first solution and react in a 70℃ water bath for 2 hours (pH = 7). 4. The solution in 3 was centrifuged, dried at 110℃, and calcined at 500℃ for 3 h to obtain Mn 0.2 ZrOx oxide; 5. Mn 0.2ZrOx oxide and SAPO-34 molecular sieve with a silicon-aluminum atomic ratio of 0.075 were physically mixed at a mass ratio of 1:2 and crushed to 20-40 mesh to obtain Mn 0.2 ZrOx / SAPO-34(0.075) tandem catalyst 6. At 350℃, 3 MPa, GHSV=1000 h -1 After 14 hours of reaction under the conditions of H2 / CO2=6, samples were taken for analysis, and the reaction products were detected online by gas chromatography. The reaction results are shown in Table 1.

[0038] Comparative Example 3: Preparation of Cd 0.1 TiOx / SAPO-34 composite materials and their applications: 1. Dissolve Cd(NO3)2·4H2O and tetrabutyl titanate in anhydrous ethanol at a molar ratio of 0.1:1 to prepare a 0.02 mol / L metal salt solution; 2. Dissolve citric acid in anhydrous ethanol to prepare a 0.03 mol / L solution; 3. Quickly add the above two solutions to the first solution and react in a 45°C water bath for 24 hours. 4. The solution in 3 was centrifuged, dried at 80℃, and calcined at 500℃ for 3 h to obtain Cd 0.1 TiOx oxide; 5. Will Cd 0.1 TiOx oxide and SAPO-34 molecular sieve with a silicon-aluminum atomic ratio of 0.075 were physically mixed at a mass ratio of 1:2 and crushed to 20-40 mesh to obtain Zn 0.05 Cd 0.1 TiOx / SAPO-34(0.075) tandem catalyst 6. At 350℃, 3 MPa, GHSV=1000 h -1 After 14 hours of reaction under the conditions of H2 / CO2=6, samples were taken for analysis, and the reaction products were detected online by gas chromatography. The reaction results are shown in Table 1.

[0039] Comparative Example 4: Preparation of Cd 0.2 ZrOx / SAPO-34 composite materials and their applications: 1. Dissolve Cd(NO3)2·4H2O and Zr(NO3)4·5H2O in 200ml of deionized water at a molar ratio of 0.2:1 to prepare a 0.02mol / L metal salt solution; 2. Dissolve ammonium carbonate in 200 ml of deionized water to prepare a 0.03 mol / L solution. 3. Quickly add the above two solutions to the first solution and react in a 70℃ water bath for 2 hours (pH = 7). 4. The solution in 3 was centrifuged, dried at 110℃, and calcined at 500℃ for 3 h to obtain Cd 0.2 ZrOx oxide; 5. Will Cd 0.2 ZrOx oxide is pressed into tablets and crushed into 20-40 mesh to obtain Cd 0.2 ZrOx catalyst; 6. At 350℃, 3 MPa, GHSV=30000 h -1 The propylene hydrogenation reaction was carried out under the conditions of H2 / C3H6=17 and C3H6 volume concentration of 2% for 9 h and sampling was performed. The reaction products were detected by gas chromatography online. The reaction results are shown in Figure 3 .

[0040] Comparative Example 5: Preparation of Ni 0.075 Cd 0.2 ZrOx / SAPO-34 composite materials and their applications: 1. Dissolve Ni(NO3)2·6H2O, Cd(NO3)2·4H2O, and Zr(NO3)4·5H2O in 200 ml of deionized water at a molar ratio of 0.075:0.2:1 to prepare a 0.02 mol / L metal salt solution. 2. Dissolve ammonium carbonate in 200 ml of deionized water to prepare a 0.03 mol / L solution. 3. Quickly add the above two solutions to the first solution and react in a 70℃ water bath for 2 hours (pH = 7). 4. The solution in 3 was centrifuged, dried at 110℃, and calcined at 500℃ for 3 h to obtain Ni 0.075 Cd 0.2 ZrOx oxide; 5. 0.075 Cd 0.2 ZrOx oxide is pressed into tablets and crushed into 20-40 mesh to obtain Ni 0.075 Cd 0.2 ZrOx catalyst 6. At 350℃, 3 MPa, GHSV=30000 h -1 The propylene hydrogenation reaction was carried out under the conditions of H2 / C3H6=17 and C3H6 volume concentration of 2% for 9 h and sampling was performed. The reaction products were detected by gas chromatography online. The reaction results are shown in Figure 3 .

[0041] Comparative Example 6: SAPO-34 molecular sieve and its applications: At 350℃, 3 MPa, GHSV=30000 h -1The propylene hydrogenation reaction was carried out under the conditions of H2 / C3H6=17 and C3H6 volume concentration of 2% for 9 h and sampling was performed. The reaction products were detected by gas chromatography online. The reaction results are shown in Figure 3 Table 1 Activity of novel ternary oxide / molecular sieve catalysts for carbon dioxide hydrogenation to C2-C4 alkanes

[0042] From Table 1 and Figure 3 The catalytic results show that the ternary metal oxide-molecular sieve composite catalyst provided by the present invention has excellent catalytic performance for CO2 hydrogenation to C2-C4 alkanes, with a selectivity of C2-C4 alkanes reaching 80.0% and a CO2 conversion rate of up to 37%. Compared with Comparative Examples 1 and 2, the use of other metal oxides such as Cd 0.2 ZrOx, the C2-C4 alkane selectivity is reduced to 45%, and the CO2 conversion rate is only 31%.

[0043] Further verification of the reaction performance of ternary metal oxides for propylene hydrogenation to alkanes in Example 4 0.075 Cd 0.2 ZrOx ternary metal oxides compared to Cd in Example 3 0.2 ZrOx binary metal oxides have stronger propylene conversion ability such as Figure 3 From Table 1 and Figure 3 The catalytic results show that the reaction pathway of CO2 hydrogenation to alkanes is that the oxide converts CO2 and H2 into methanol, the methanol is further converted into olefins by H-SAPO-34, and the olefins are finally converted into alkanes on the surface of the oxide. The specific reaction process is as follows Figure 4 shown.

[0044] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form or substance. It should be pointed out that ordinary technicians in this technical field can make several improvements and supplements without departing from the method of the present invention. These improvements and supplements should also be regarded as the scope of protection of the present invention. Any equivalent changes, modifications and evolutions made by technicians familiar with this profession without departing from the spirit and scope of the present invention by using the technical content disclosed above are all equivalent embodiments of the present invention; at the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A ternary metal oxide-molecular sieve composite material for catalyzing CO2 hydrogenation to produce light alkanes, comprising a ternary metal oxide and a molecular sieve, characterized in that: The general formula of the ternary metal oxide is M1aM2bM3cOx, wherein: The M1 is one of Fe, Co, Ni, Pt, Pd, Cu, and Zn; The M2 is one of Cr, Mn, Mo, Cd, Ga, and In; The M3 is one of Ce, Zr, Ti, and Al; The molar ratio a:b:c is 0.01-0.5: 0.05-1: 1; The molecular sieve is at least one of H-SAPO-34, H-SAPO-18, H-RUB-13, and H-SZZ-13; The mass ratio of the ternary metal oxide to the molecular sieve is 1:0.1-10.

2. The ternary metal oxide-molecular sieve composite material according to claim 1, characterized in that: The silicon-aluminum atomic ratio (Si / Al) in the molecular sieve is 0.025-200:

1.

3. The ternary metal oxide-molecular sieve composite material according to claim 1, characterized in that: The ternary metal oxides are ZnCdTiOx, NiMnZrOx, NiCdZrOx, ZnCrTiOx, NiInZrOx, NiCdCeOx, ZnCdAlOx, and NiMnCeOx.

4. The ternary metal oxide-molecular sieve composite material according to claim 1, characterized in that: The a:b:c is 0.05:0.1:1, 0.1:0.1:1, 0.2:0.1:1, 0.1:0.2:1, and 0.75:0.2:

1.

5. The ternary metal oxide-molecular sieve composite material according to claim 1, characterized in that: The ternary metal oxide is Zn 0.05 Cd 0.1 TiOx、Zn 0.1 Cd 0.1 TiOx、Zn 0.2 Cd 0.1 TiOx、Ni 0.1 Mn 0.2 ZrOx、Ni 0.075 Cd 0.2 ZrOx.

6. A method for preparing the ternary metal oxide-molecular sieve composite material according to claim 1 or 2, characterized in that: The following steps are included (1) Mixing a soluble metal salt and a solvent to obtain a metal salt solution; the soluble metal salt is a water-soluble M1, M2, M3 metal salt or a soluble organic M1, M2, M3 metal salt; (2) mixing a complexing agent with a solvent to obtain a complexing agent solution; the complexing agent is a precipitant or a complexing agent; (3) slowly adding the above-mentioned composite agent solution dropwise to the above-mentioned metal salt solution to prepare a ternary metal oxide solid precursor precipitate; (4) aging, washing, drying, and calcining the ternary metal oxide solid precursor to obtain a ternary metal oxide; (5) mixing the ternary metal oxide and molecular sieve to obtain a ternary metal oxide-molecular sieve composite material; The step (3) is any one of steps (3.1) to (3.2): (3.1) dissolving the soluble metal salt and the precipitant in water respectively, and adding the precipitant aqueous solution dropwise to the metal salt aqueous solution to carry out a precipitation reaction to obtain a ternary metal oxide solid precursor; (3.2) The soluble metal salt and the complexing agent are dissolved in organic solvents respectively, and the complexing agent solution is added dropwise to the metal salt solution to carry out a complexation reaction to obtain a ternary metal oxide solid precursor.

7. The preparation method according to claim 6, characterized in that The precipitant in step (3) includes one or more of water-soluble carbonates, water-soluble bicarbonates and water-soluble hydroxides; the complexing agent includes one or more of glucose, citric acid, tartaric acid, salicylic acid, oxalic acid and adipic acid; the solvent is water or an organic solvent; The organic solvent in step (3.2) is any one of methanol, ethanol, propylene glycol, ethylene glycol, and n-propanol; The molar ratio of the solvent to the complexing agent in step (2) is 200-3500:1; In the step (3), the molar ratio of total metal ions in the metal salt solution to the complexing agent solution is 1:0.5-5; and the molar ratio of the solvent to the metal ions in the metal salt solution is 200-3500:

1.

8. The preparation method according to claim 6, wherein The temperature of the precipitation and complexation reaction is 60-150°C; the aging time of the precipitation and complexation reaction is 3-20h; the temperature of the drying treatment is 50-150°C; the temperature of the roasting treatment is 350-700°C; and the holding time of the roasting treatment is 2-10h.

9. Use of the ternary metal oxide-molecular sieve composite material according to any one of claims 1 to 5 or the ternary metal oxide-molecular sieve composite material prepared by the preparation method according to any one of claims 6 to 8 in catalytic CO2 hydrogenation to produce light alkanes.

10. The use according to claim 9, characterized in that: The catalytic conditions for catalytic CO2 hydrogenation to produce light alkanes are a reaction pressure of 0.1-6 MPa, a reaction temperature of 250-420 °C, and a reaction space velocity of 500-40000 mL g cat -1 h -1 , H2 / CO2 is 1 / 1 to 1 / 12; the preferred reaction space velocity is 1000 mL g cat -1 h -1 .

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