Method for producing primary alcohol by hydrogenation of co2 using two catalysts placed in series

Abstract

The application relates to a series catalyst and application of the series catalyst in CO2 hydrogenation reaction. The catalyst comprises two components, a first component is mainly a single-atom cobalt and nickel-based catalyst; and a second component is mainly a supported cobalt and iron-based catalyst. By using the catalyst provided by the application, a process of preparing mixed primary alcohols from CO2 and H2 in one step is realized, a new way is provided, the process is more simple, and higher economic efficiency is achieved. The application provides a new way of high-efficiency utilization of CO2.

Description

Technical Field

[0001] This invention relates to a highly efficient CO2 hydrogenation tandem catalyst, applied to the catalytic conversion of CO2 to alcohols, belonging to the field of energy and chemical engineering. Specifically, it relates to a method for preparing and applying the tandem catalyst. More specifically, it relates to a catalyst coupling of reverse water-gas shift reaction and Fischer-Tropsch synthesis for alcohol production, achieving highly efficient conversion at the process level, thereby greatly increasing the efficient utilization of carbon cycling. Background Technology

[0002] The development and utilization of petrochemical resources has greatly promoted socio-economic development, but it has also led to a surge in atmospheric carbon dioxide levels, exacerbating the greenhouse effect and causing a host of environmental problems. Therefore, CO2 capture and utilization (CCU) strategies have become a research hotspot in recent years. The reaction of CO2 hydrogenation to produce mixed primary alcohols has attracted widespread attention, and the development of efficient non-precious metal catalysts for the industrial application of CO2 hydrogenation is urgently needed and will be an important step in the future carbon cycle.

[0003] Patent 201610159718.4 reports a monolithic catalyst for the hydrogenation of CO2 to lower alcohols and its preparation method, with isobutanol being the main product. Patents 201811636160.X and 202010441071.0 primarily introduce the application of iron-based and copper-based catalysts in the hydrogenation of CO2 to ethanol. Currently, there are few patent reports on the conversion of CO2 to C... 6+ Applications of alcohols. Summary of the Invention

[0004] The purpose of this invention is to provide a catalyst and its application in the preparation of mixed primary alcohols by CO2 hydrogenation, which couples the reverse water-gas shift reaction and the Fischer-Tropsch synthesis reaction to realize a new route from CO2 to mixed primary alcohols.

[0005] A tandem catalyst comprising two components:

[0006] The preparation method of the first component catalyst includes the following steps:

[0007] (1) Disperse the carbon support and the soluble cobalt and / or nickel salts used in water and sonicate for 0.5-3 h (preferably 1-2 h); then add the nitrogen-containing ligand and stir for 0.5-3 h (preferably 1-2 h) to make it uniformly dispersed. Rotary evaporate the suspension to obtain a solid, and dry it at 323-403 K (preferably 343-383 K) for 6-48 h (preferably 12-24 h) to obtain the first component catalyst precursor.

[0008] The soluble salt is one or more of the following: cobalt and / or nickel nitrates, acetates, sulfates, hydrochlorides, and citrates. The nitrogen-containing ligand used is one or more of the following: melamine, dicyandiamide, and cyanamide (preferably one or two of melamine and dicyandiamide); the carbon used is one or more of the following: carbon nanotubes, activated carbon, carbon nanofibers, and graphene (preferably one or two of activated carbon and carbon nanotubes).

[0009] (2) The obtained first-component catalyst precursor is calcined at 773–1273 K (preferably 873–1073 K) for 1–5 h (preferably 2–4 h) under an inert atmosphere to obtain the first-component catalyst; the inert atmosphere used is one or more of He, Ar, and N2; the gas space velocity is 1000–5000 h⁻¹. -1 (Preferred 2000-4000h) -1 );

[0010] The content of the active component cobalt and / or nickel is 1-10 wt% (preferably 1-5 wt%) of the carbon support; the nitrogen-containing ligand is 10-40 wt% (preferably 20-30 wt%) of the carbon support.

[0011] The method for preparing the second-component supported catalyst includes the following steps:

[0012] (1) First, prepare a mixed solution of one or more metal salts of soluble active metals and one or more additives, impregnate the support with an equal volume at room temperature, and then air dry for 6-48 hours (preferably 12-24 hours) to obtain a solid. Dry the solid at 323-403K (preferably 343-383K) for 6-48 hours (preferably 12-24 hours) to obtain the second component precursor of the catalyst.

[0013] The carrier is one or more of alumina, titanium dioxide, silicon dioxide, activated carbon, and ordered mesoporous carbon (preferably one or two of activated carbon and ordered mesoporous carbon); the active component is one or more of metallic cobalt, metallic iron, cobalt carbide, and iron carbide (preferably one or two of cobalt carbide and iron carbide), and the content of the active component is 5-35 wt% (preferably 10-25 wt%) of the catalyst weight; the promoter is one or more of alkali metals, alkaline earth metals, rare earth metals, and transition metals (preferably one or more of lithium, chromium, manganese, zirconium, and nickel), and the content of the promoter is 0.1-10 wt% (preferably 0.3-5 wt%) of the catalyst weight.

[0014] (2) The obtained second-component catalyst precursor is calcined at 473–673 K (preferably 493–623 K) for 1–5 h (preferably 2–4 h) under an inert atmosphere to obtain the second-component catalyst; the inert atmosphere used is one or more of He, Ar, and N2; the gas space velocity is 1000–5000 h⁻¹. -1 (Preferred 2000-4000h) -1 ), and obtain the second component catalyst;

[0015] (3) The second component catalyst needs to be pretreated. First, the catalyst needs to be activated in a hydrogen-containing atmosphere with a hydrogen volume content of 5% to 100% (preferably 10% to 100%). The gases in the hydrogen-containing mixture other than hydrogen are one or more of nitrogen, argon, or helium. The activation temperature is 673 to 873 K (preferably 673 to 823 K), the pressure is 0.1 to 2.5 MPa (preferably 0.1 to 1.0 MPa), and the gas space velocity is 300 to 6000 h⁻¹. -1 (Preferred 1000~3000h) -1 The catalyst is prepared by activation for 6-72 hours. Then, it is switched to a secondary pretreatment using syngas (a mixture of H2 and CO) to achieve stable activity and selectivity. The molar ratio of H2 to CO in the mixture is 0.4-4.0 (preferably 1.0-3.0), the pretreatment temperature is 443-523 K (preferably 463-503 K), the pressure is 0.1-10.0 MPa (preferably 0.5-5.0 MPa), and the space velocity is 100-10000 h⁻¹. -1 (Preferred 1000-5000h) -1 Processing time: 2–96 hours;

[0016] (4) After pretreatment, the catalyst needs to be passivated in an oxygen-containing atmosphere. The oxygen volume content in the oxygen-containing atmosphere is 0.1% to 10% (preferably 0.5% to 2%). The gases other than oxygen in the oxygen-containing mixture are one or more of nitrogen, argon, or helium. The passivation temperature is room temperature, the pressure is 0.1 to 1.0 MPa (preferably 0.1 to 0.5 MPa), and the gas space velocity is 300 to 6000 h⁻¹. -1 (Preferred 500-2000h) -1 The second component catalyst was prepared by activating it for 1 to 6 hours.

[0017] The reactor for the preparation of primary alcohols by CO2 hydrogenation adopts a two-stage temperature-controlled fixed-bed reactor. The two components of the catalyst are packed in the fixed-bed reactor in the following manner: the first component catalyst is in the upper layer of the reactor and the second component catalyst is in the lower layer of the reactor. CO2 and H2 feedstocks flow sequentially through the upper catalyst bed and the lower catalyst bed.

[0018] The specific reaction conditions are as follows: CO2 and H2 are used as raw materials, with a H2 to CO2 feed volume ratio of 1 to 5 (preferably 2 to 3); the two-stage reaction temperatures are: upper stage 573 to 873 K (preferably 603 to 773 K), lower stage 443 to 523 K (preferably 453 to 503 K); the mass ratio of the bilayer catalyst is 0.3 to 3 (preferably 0.5 to 1.5); the reaction pressure is 1 to 5 MPa (preferably 2 to 3 MPa); and the total space velocity is 500 to 20000 h⁻¹. -1 (Preferred 2000~10000h) -1 The primary alcohol is a mixture of C1-C20 primary alcohols.

[0019] The beneficial effects of this invention are as follows: a double-layer tandem catalyst was successfully prepared, a new approach was proposed, and this catalyst was applied to the CO2 hydrogenation reaction, which improved the selectivity of mixed primary alcohols in the product and the catalyst has good stability. Attached Figure Description

[0020] Figure 1 This is an electron microscope image of the catalyst. Detailed Implementation

[0021] To better understand the present invention, the technical solution of the present invention will be described in detail below with reference to the embodiments. The embodiments given do not limit the scope of protection of the present invention.

[0022] CO2 and H2 feedstocks flow sequentially through the upper and lower catalyst beds of the fixed bed.

[0023] Example 1

[0024] First component: Single-atom catalyst

[0025] First, 1.20 g of activated carbon and 0.38 g of cobalt nitrate hexahydrate were dispersed in 10 ml of water and sonicated for 1 hour. Then, 5 g of melamine was added and stirred for 1 hour to ensure uniform dispersion. The suspension was then rotary evaporated to obtain a solid, which was dried at 383 K for 8 hours and then dried under an argon atmosphere with a gas hourly space velocity of 2000 h⁻¹. -1 The first component, 3% Co-NC catalyst, was obtained by gradually increasing the temperature to 1073K and calcining for 2 hours.

[0026] Second component supported catalyst:

[0027] First, 4.56 g of cobalt nitrate hexahydrate, 0.54 g of nickel nitrate hexahydrate, and 0.32 g of zirconium nitrate were dissolved in 10 g of water. An equal volume of this solution was then impregnated with 8.5 g of activated carbon support at room temperature. The mixture was subsequently air-dried for 8 hours to obtain a solid, which was then dried at 403 °C for 8 hours. Finally, the solid was subjected to an argon atmosphere with a gas hourly space velocity (GHSV) of 2000 h⁻¹. -1Calcination at 573 K for 2 h was followed by pretreatment at 10% H2 / Ar activation temperature of 773 K, pressure of 1.0 MPa, and gas space velocity of 4000 h⁻¹. -1 Activation was performed for 24 hours, followed by cooling to 353K, and then switching to syngas (H2 / CO = 2), at 463K, 4.0MPa, for 5000 hours. -1 After being treated under the specified conditions for 24 hours, cooled to room temperature, and then subjected to 1% O2 / Ar, 0.1 MPa, and 1000 h⁻¹. -1 After passivation for 2 hours, the second component, 15% Co 0.02% Ni 0.01% Zr / AC catalyst, was prepared.

[0028] The first and second catalyst components were loaded separately into the lower bed of a fixed bed. The mass ratio of the two catalyst components was 1, the volume ratio of H2 to CO2 feed was 3, the two-stage reaction temperatures were 773 K for the upper bed and 503 K for the lower bed, the reaction pressure was 3 MPa, and the total space velocity was 5000 h⁻¹. -1 After stabilizing for 12 hours, samples were taken every 24 hours to analyze the concentration of each component in the tail gas, the composition of the liquid phase products, and the yield of the liquid phase products. The results are listed in Appendix Table 1.

[0029] Example 2

[0030] First component: Single-atom catalyst

[0031] First, 1.50 g of carbon nanotubes and 0.48 g of nickel nitrate hexahydrate were dispersed in 10 ml of water and sonicated for 2 hours. Then, 6 g of dicyandiamide was added and stirred for 2 hours to ensure uniform dispersion. The suspension was then subjected to rotary evaporation to obtain a solid, which was dried at 373 K for 12 hours. Subsequently, the solid was dried under a nitrogen atmosphere with a gas hourly space velocity of 3000 h⁻¹. -1 The first component, 4% Ni-NC catalyst, was obtained by gradually increasing the temperature to 973K and calcining for 3 hours.

[0032] Second component supported catalyst:

[0033] First, 6.84 g of ferric nitrate nonahydrate, 0.33 g of manganese nitrate, and 0.52 g of chromium nitrate were dissolved in 10 g of water. This solution was then used to impregnate 9.5 g of alumina carrier at room temperature. The mixture was subsequently air-dried for 12 hours to obtain a solid, which was then dried at 293°C for 12 hours. Finally, the solid was placed under an argon atmosphere with a gas hourly space velocity (GHSV) of 3000 h⁻¹. -1 Calcination at 583K for 1 hour; followed by pretreatment with 20% H2 / Ar activation at 783K, 1.5MPa, and a gas space velocity of 3000 h⁻¹. -1 Activation was performed for 23 hours, followed by cooling to 353K, and then switching to syngas (H2 / CO = 3), at 473K, 3.0MPa, for 3000 hours. -1The sample was treated under the following conditions for 24 hours, then cooled to room temperature and subjected to 5% O2 / Ar, 0.2 MPa, and 1000 h⁻¹. -1 After passivation for 2 hours, the second component, 20% Fe0.01Mn0.02Cr / Al2O3 catalyst, was prepared.

[0034] The first and second catalyst components were loaded separately into the lower bed of a fixed bed. The mass ratio of the two catalyst components was 0.5, the H2 to CO2 feed volume ratio was 4, and the two-stage reaction temperatures were 873 K for the upper bed and 503 K for the lower bed. The reaction pressure was 2 MPa, and the total space velocity was 6000 h⁻¹. -1 After stabilizing for 12 hours, samples were taken every 24 hours to analyze the concentration of each component in the tail gas, the composition of the liquid phase products, and the yield of the liquid phase products. The results are listed in Appendix Table 1.

[0035] Example 3

[0036] First component: Single-atom catalyst

[0037] First, 1.50g of carbon balls and 0.28g of cobalt nitrate hexahydrate were dispersed in 10ml of water and sonicated for 1 hour. Then, 6g of cyanamide was added and stirred for 1 hour to ensure uniform dispersion. The suspension was then rotary evaporated to obtain a solid, which was dried at 363K for 13 hours and subsequently dried under a helium atmosphere with a gas hourly space velocity of 4000 h⁻¹. -1 The first component, 3% Co-NC catalyst, was obtained by gradually increasing the temperature to 1173K and calcining for 3 hours.

[0038] Second component supported catalyst:

[0039] First, 5.03 g of ferric nitrate hexahydrate, 0.55 g of nickel nitrate hexahydrate, and 0.44 g of zirconium nitrate were dissolved in 10 g of water. This solution was then used to impregnate an equal volume of 10.0 g of silica support at room temperature. The mixture was subsequently air-dried for 8 hours to obtain a solid, which was then dried at 403 °C for 8 hours. Finally, the solid was placed under an argon atmosphere with a gas hourly space velocity (GHSV) of 3000 h⁻¹. -1 Calcination at 573K for 2 hours; followed by pretreatment with 20% H2 / Ar activation at 773K, 1.0MPa, and a gas space velocity of 4000 h⁻¹. -1 Activation was performed for 24 hours, followed by cooling to 353K, and then switching to syngas (H2 / CO = 2), at 463K, 4.0MPa, for 5000 hours. -1 The sample was treated under the following conditions for 24 hours, then cooled to room temperature and subjected to 10% O2 / Ar, 0.1 MPa, and 1000 h⁻¹. -1 After passivation for 2 hours, the second component, 14%Fe0.02%Ni0.015%Zr / SiO2 catalyst, was prepared.

[0040] The first and second catalyst components were loaded onto a fixed bed, in the lower layer. The mass ratio of the two catalyst components was 1.5, the H2 to CO2 feed volume ratio was 3, and the two-stage reaction temperatures were 773 K for the upper bed and 503 K for the lower bed. The reaction pressure was 3 MPa, and the total space velocity was 5000 h⁻¹. -1 After stabilizing for 12 hours, samples were taken every 24 hours to analyze the concentration of each component in the tail gas, the composition of the liquid phase products, and the yield of the liquid phase products. The results are listed in Appendix Table 1.

[0041] Example 4

[0042] The first group of catalysts consists of single-atom catalysts:

[0043] First, 1.33g of activated carbon and 0.48g of nickel nitrate hexahydrate were dispersed in 10ml of water and sonicated for 1 hour. Then, 6g of melamine was added and stirred for 1 hour to ensure uniform dispersion. The suspension was then rotary evaporated to obtain a solid, which was dried at 393K for 8 hours and then dried under an argon atmosphere with a gas hourly space velocity of 2000 h⁻¹. -1 The first component, 5% Ni-NC catalyst, was obtained by gradually increasing the temperature to 1273K and calcining for 1 hour.

[0044] Second component supported catalyst:

[0045] First, 4.99 g of ferric nitrate hexahydrate, 0.53 g of nickel nitrate hexahydrate, and 0.68 g of manganese nitrate were dissolved in 10 g of water. This solution was then used to impregnate 9.5 g of titanium dioxide carrier at room temperature. The mixture was subsequently air-dried for 8 hours to obtain a solid, which was then dried at 403 °C for 8 hours. Finally, the solid was placed under an argon atmosphere with a gas hourly space velocity (GHSV) of 2000 h⁻¹. -1 Calcination at 573K for 3 hours; followed by pretreatment with 40% H2 / Ar activation at 783K, 0.5MPa, and a gas space velocity of 2000 h⁻¹. -1 Activation was performed for 24 hours, followed by cooling to 353 K, and then switching to syngas (H2 / CO = 3), at 463 K, 4.0 MPa, for 5000 h. -1 After being treated under the specified conditions for 24 hours, cooled to room temperature, and then subjected to 1% O2 / Ar, 0.1 MPa, and 1000 h⁻¹. -1 After passivation for 2 hours, the second component, 14%Fe0.02%Ni0.03%Mn catalyst, was obtained.

[0046] The first and second catalyst components were loaded separately into the lower bed of a fixed bed. The mass ratio of the two catalyst components was 1, the volume ratio of H2 to CO2 feed was 1, and the two-stage reaction temperatures were 873 K for the upper bed and 513 K for the lower bed. The reaction pressure was 2 MPa, and the total space velocity was 7000 h⁻¹. -1 After stabilization for 12 hours, samples were taken every 24 hours to analyze the concentration of each component in the tail gas, the composition of the liquid phase products, and the yield of the liquid phase products. The results are listed in Appendix Table 1.

[0047] Example 5

[0048] First component: Single-atom catalyst

[0049] First, 1.20 g of carbon nanofibers and 0.23 g of cobalt nitrate hexahydrate were dispersed in 10 ml of water and sonicated for 2 hours. Then, 6 g of melamine was added and stirred for 2 hours to ensure uniform dispersion. The suspension was then subjected to rotary evaporation to obtain a solid, which was dried at 383 K for 8 hours and then dried under an argon atmosphere with a gas hourly space velocity of 4000 h⁻¹. -1 The catalyst was gradually heated to 873K and calcined for 4 hours to obtain the first component catalyst, 2.5% Co-NC.

[0050] Second component supported catalyst:

[0051] First, 4.67 g of cobalt nitrate hexahydrate, 0.58 g of manganese nitrate hexahydrate, and 0.38 g of zirconium nitrate were dissolved in 10 g of water and impregnated with an equal volume of 9.5 g of ordered mesoporous carbon support at room temperature. The mixture was then air-dried for 10 h to obtain a solid, which was dried at 423 °C for 12 h. Subsequently, the solid was subjected to a nitrogen atmosphere with a gas hourly space velocity (GHSV) of 2000 h⁻¹. -1 Calcination at 593K for 2 hours; followed by pretreatment with 40% H2 / Ar activation at 773K, 2.0MPa, and a gas space velocity of 3000 h⁻¹. -1 Activation was performed for 24 hours, followed by cooling to 353K, and then switching to syngas (H2 / CO = 2), at 463K, 4.0MPa, for 5000 hours. -1 After being treated under the specified conditions for 24 hours, cooled to room temperature, and then subjected to 4% O2 / Ar, 0.2 MPa, and 2000 h⁻¹. -1 After passivation for 2 hours, the second component, 13% Co0.02Mn0.01Zr / mesoporous carbon catalyst, was prepared.

[0052] The first and second catalyst components were loaded separately into the lower bed of a fixed bed. The mass ratio of the two catalyst components was 0.5. The H2 to CO2 feed volume ratio was 1. The two-stage reaction temperatures were 873 K for the upper bed and 493 K for the lower bed. The reaction pressure was 2 MPa, and the total space velocity was 4000 h⁻¹. -1 After stabilizing for 12 hours, samples were taken every 24 hours to analyze the concentration of each component in the tail gas, the composition of the liquid phase products, and the yield of the liquid phase products. The results are listed in Appendix Table 1.

[0053] Example 6

[0054] First component: Single-atom catalyst

[0055] First, 1.20 g of graphene and 0.38 g of cobalt nitrate hexahydrate were dispersed in 10 ml of water and sonicated for 1 hour. Then, 5 g of melamine was added and stirred for 1 hour to ensure uniform dispersion. The suspension was then subjected to rotary evaporation to obtain a solid, which was dried at 383 K for 8 hours and then dried under an argon atmosphere with a gas hourly space velocity of 2000 h⁻¹. -1 The first component catalyst, 4% Co-NC, was obtained by gradually increasing the temperature to 1073K and calcining for 2 hours.

[0056] Second component supported catalyst:

[0057] First, 4.56 g of cobalt nitrate hexahydrate, 0.54 g of nickel nitrate hexahydrate, and 0.32 g of zirconium nitrate were dissolved in 10 g of water. An equal volume of this solution was then impregnated with 8.5 g of activated carbon support at room temperature. The mixture was subsequently air-dried for 8 hours to obtain a solid, which was then dried at 403 °C for 8 hours. Finally, the solid was subjected to an argon atmosphere with a gas hourly space velocity (GHSV) of 2000 h⁻¹. -1 Calcination at 573 K for 2 h was followed by pretreatment at 10% H2 / Ar activation temperature of 773 K, pressure of 1.0 MPa, and gas space velocity of 4000 h⁻¹. -1 Activation was performed for 24 hours, followed by cooling to 353K, and then switching to syngas (H2 / CO = 2), at 463K, 4.0MPa, for 5000 hours. -1 After being treated under the specified conditions for 24 hours, cooled to room temperature, and then subjected to 1% O2 / Ar, 0.1 MPa, and 1000 h⁻¹. -1 After passivation for 2 hours, the second component, 13% Co 0.02% Ni 0.01% Zr / AC catalyst, was prepared.

[0058] The first and second catalyst components were loaded separately into the lower bed of a fixed bed. The mass ratio of the two catalyst components was 1, the volume ratio of H2 to CO2 feed was 3, and the two-stage reaction temperatures were 773 K for the upper bed and 503 K for the lower bed. The reaction pressure was 3 MPa, and the total space velocity was 5000 h⁻¹. -1 After stabilizing for 12 hours, samples were taken every 24 hours to analyze the concentration of each component in the tail gas, the composition of the liquid phase products, and the yield of the liquid phase products. The results are listed in Appendix Table 1.

[0059] Comparative Example 1

[0060] First, 1.20 g of activated carbon and 0.38 g of cobalt nitrate hexahydrate were dispersed in 10 ml of water and sonicated for 1 hour. Then, 5 g of melamine was added and stirred for 1 hour to ensure uniform dispersion. The suspension was then rotary evaporated to obtain a solid, which was dried at 383 K for 8 hours and then dried under an argon atmosphere with a gas hourly space velocity of 2000 h⁻¹. -1 The first component, 4% Co-NC catalyst, was obtained by gradually increasing the temperature to 1073K and calcining for 2 hours.

[0061] The catalyst was loaded onto a fixed bed. The H2 to CO2 feed volume ratio was 3, the reaction temperature was 773 K in the upper bed, the reaction pressure was 3 MPa, and the total space velocity was 5000 h⁻¹. -1 After stabilizing for 12 hours, samples were taken every 24 hours to analyze the concentration of each component in the tail gas, the composition of the liquid phase products, and the yield of the liquid phase products. The results are listed in Appendix Table 1.

[0062] Table 1

[0063] Performance evaluation and product analysis of catalysts for CO hydrogenation reaction.

[0064]

[0065]

Claims

1. A method for producing primary alcohols by CO2 hydrogenation using two catalysts placed in series, characterized in that, The catalyst contains two components: The preparation process of the first component catalyst includes the following steps: (1) Disperse the carbon support and the soluble cobalt and / or nickel salts used in water and sonicate for 0.5-3 h; then add the nitrogen-containing ligand and stir for 0.5-3 h to make it uniformly dispersed. Rotary evaporate the suspension to obtain the solid, and dry it at 323-403 K for 6-48 h to obtain the first component catalyst precursor. The soluble salts are one or more of the following: nitrates, acetates, sulfates, hydrochlorides, and citrates of cobalt and / or nickel; The nitrogen-containing ligands used are one or more of melamine, dicyandiamide, and cyanamide; The carbon used is one or more of the following: carbon nanotubes, activated carbon, carbon nanofibers, and graphene. (2) The first component catalyst precursor obtained is calcined at 773~1273 K for 1~5 h under an inert atmosphere to obtain the first component catalyst; the inert atmosphere used is one or more of He, Ar, and N2; the gas space velocity is 1000~5000 h. -1 ; The content of the active component cobalt and / or nickel is 1-10 wt% of the weight of the carbon support; the content of the nitrogen-containing ligand is 10-40 wt% of the weight of the carbon support. The preparation process of the second component supported catalyst includes the following steps: (1) First, prepare a mixed solution of one or more metal salts of soluble active metals and one or more additives, impregnate the support with an equal volume at room temperature, and then air dry for 6-48 h to obtain a solid. Dry the solid at 323-403 K for 6-48 h to obtain the second component catalyst precursor. The carrier is one or more of alumina, titanium dioxide, silicon dioxide, activated carbon, and ordered mesoporous carbon; The active component is one or more of metallic cobalt, metallic iron, cobalt carbide, and iron carbide, and the content of the active component is 5 to 35 wt% of the catalyst weight. The additives are one or more of alkali metals, alkaline earth metals, rare earth metals, and transition metals, and the additive content is 0.1~10 wt% of the catalyst weight. (2) The obtained second-component catalyst precursor is calcined at 473~673 K for 1~5 h under an inert atmosphere to obtain the second-component catalyst; the inert atmosphere used is one or more of He, Ar, and N2; the gas space velocity is 1000~5000 h⁻¹. -1 This yields the second component catalyst. (3) The second component catalyst needs to be pretreated. First, the catalyst needs to be activated in a hydrogen-containing atmosphere with a hydrogen volume content of 5% to 100%. The gases in the hydrogen-containing mixture other than hydrogen are one or more of nitrogen, argon, or helium. The activation temperature is 673 to 873 K, the pressure is 0.1 to 2.5 MPa, and the gas space velocity is 300 to 6000 h⁻¹. -1 The activated catalyst was prepared by activation for 6-72 hours. Subsequently, a secondary pretreatment was performed using a mixture of syngas (H2 and CO) to stabilize activity and selectivity. The molar ratio of H2 to CO in the mixture was 0.4-4.0, the pretreatment temperature was 443-523 K, the pressure was 0.1-10.0 MPa, and the space velocity was 100-10000 h⁻¹. -1 Processing time: 2-96 hours; (4) After pretreatment, the catalyst needs to be passivated in an oxygen-containing atmosphere with an oxygen volume content of 0.1% to 10%. The oxygen-containing mixture contains one or more of nitrogen, argon, or helium, excluding oxygen. The passivation temperature is room temperature, the pressure is 0.1 to 1.0 MPa, and the gas space velocity is 300 to 6000 h⁻¹. -1 The second component catalyst was prepared by activating it for 1-6 hours; The reactor for the preparation of primary alcohols by CO2 hydrogenation adopts a two-stage temperature-controlled fixed-bed reactor. The two components of the catalyst are loaded in the fixed-bed reactor in the following manner: the first component catalyst is in the upper layer of the reactor and the second component catalyst is in the lower layer of the reactor. CO2 and H2 feedstocks flow sequentially through the upper catalyst bed and the lower catalyst bed; The specific reaction conditions are as follows: CO2 and H2 are used as raw materials, the H2 to CO2 feed volume ratio is 1-5, the two-stage reaction temperatures are: 573-873 K for the upper catalyst bed and 443-523 K for the lower catalyst bed, the mass ratio of the two catalyst layers is 0.3-3, the reaction pressure is 1-5 MPa, and the total space velocity is 500-20000 h⁻¹. -1 .

2. The method according to claim 1, characterized in that: The catalyst contains two components: The preparation process of the first component catalyst includes the following steps: (1) Disperse the carbon support and the soluble cobalt and / or nickel salts used in water and sonicate for 1-2 h; then add nitrogen-containing ligands and stir for 1-2 h to make them uniformly dispersed. Rotary evaporate the suspension to obtain the solid, and dry it at 343-383 K for 12-24 h to obtain the first component catalyst precursor. The soluble salts are one or more of the following: nitrates, acetates, sulfates, hydrochlorides, and citrates of cobalt and / or nickel; The nitrogen-containing ligands used are one or both of melamine and dicyandiamide; The carbon used is one or both of activated carbon and carbon nanotubes; (2) The first component catalyst precursor obtained is calcined at 873-1073 K for 2-4 h under an inert atmosphere to obtain the first component catalyst; the inert atmosphere used is one or more of He, Ar, and N2; the gas space velocity is 2000-4000 h⁻¹. -1 ; The content of the active component cobalt and / or nickel is 1-5 wt% of the weight of the carbon support; the content of nitrogen-containing ligands is 20-30 wt% of the weight of the carbon support. The preparation process of the second component supported catalyst includes the following steps: (1) First, prepare a mixed solution of one or more metal salts of soluble active metals and one or more additives, impregnate the support with an equal volume at room temperature, and then air dry for 12-24 h to obtain a solid. Dry the solid at 343-383 K for 12-24 h to obtain the second component catalyst precursor. The carrier is one or both of activated carbon and ordered mesoporous carbon; The active component is one or two of cobalt carbide and iron carbide, and the content of the active component is 10~25wt% of the catalyst weight. The additives are one or more of lithium, chromium, manganese, zirconium, and nickel, and the additive content is 0.3~5 wt% of the catalyst weight. (2) The obtained second-component catalyst precursor is calcined at 493-623 K for 2-4 h under an inert atmosphere to obtain the second-component catalyst; the inert atmosphere used is one or more of He, Ar, and N2; the gas space velocity is 2000-4000 h⁻¹. -1 And thus, the second component catalyst was obtained; (3) The second component catalyst needs to be pretreated. First, the catalyst needs to be activated in a hydrogen-containing atmosphere with a hydrogen volume content of 10% to 100%. The gases in the hydrogen-containing mixture other than hydrogen are one or more of nitrogen, argon, or helium. The activation temperature is 673 to 823 K, the pressure is 0.1 to 1.0 MPa, and the gas space velocity is 1000 to 3000 h⁻¹. -1 The activated catalyst was prepared by activation for 6-72 hours. Subsequently, a secondary pretreatment was performed using a mixture of syngas (H2 and CO) to stabilize activity and selectivity. The molar ratio of H2 to CO in the mixture was 1.0-3.0, the pretreatment temperature was 463-503 K, the pressure was 0.5-5.0 MPa, and the space velocity was 1000-5000 h⁻¹. -1 Processing time: 2-96 hours; (4) After pretreatment, the catalyst needs to be passivated in an oxygen-containing atmosphere with an oxygen volume content of 0.5% to 2%. The oxygen-containing mixture contains one or more of nitrogen, argon, or helium, excluding oxygen. The passivation temperature is room temperature, the pressure is 0.1 to 0.5 MPa, and the gas space velocity is 500 to 2000 h⁻¹. -1 The second component catalyst was prepared by activating it for 1 to 6 hours.

3. The method according to claim 1, characterized in that: The specific reaction conditions are as follows: CO2 and H2 are used as raw materials, the H2 to CO2 feed volume ratio is 2-3, the two-stage reaction temperatures are: upper catalyst bed 603-773 K, lower catalyst bed 453-503 K, the mass ratio of the two catalyst layers is 0.5-1.5, the reaction pressure is 2-3 MPa, and the total space velocity is 2000-10000 h⁻¹. -1 .

4. The method according to claim 1, characterized in that: The primary alcohol is a mixture of C1-C20 primary alcohols.

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