Carbon dioxide hydrogenation to methanol catalyst prepared by ammonia-assisted magnesium silicide reduction method and application thereof

Abstract

The application discloses a kind of carbon dioxide hydrogenation preparation methanol catalysts prepared by ammonia assisted magnesium silicide reduction method and application thereof, belong to catalytic preparation technical field, preparation method includes: copper nitrate is mixed with zinc nitrate and dissolved in alcohol solvent and ammonia is added, then magnesium silicide is added to obtain reaction system, after 2~8 h of mixed reaction at 30~70 ℃, the obtained product solution is centrifuged, washed and dried, the dried product is first placed in air atmosphere 0~850 ℃ treatment 1~8 h, then placed in reducing atmosphere 300~600 ℃ calcination 1~8 h, obtain the carbon dioxide hydrogenation preparation methanol catalyst;The silicon is introduced into Cu-ZnO catalyst system in a brand-new way in the application, and the carbon dioxide hydrogenation preparation methanol catalyst obtained can realize high activity and high selectivity of carbon dioxide catalytic hydrogenation to prepare methanol under the pressure condition of 0~0.5MPa.

Description

Technical Field

[0001] This invention relates to the field of catalyst preparation technology, specifically to a catalyst for the hydrogenation of carbon dioxide to methanol prepared by the ammonia-assisted magnesium silicide reduction method and its application. Background Technology

[0002] The rapid depletion of fossil fuels and the accompanying excessive carbon dioxide emissions have made the search for efficient and low-cost fuel production pathways and the development of technologies for capturing and recovering excess carbon dioxide from the atmosphere urgent. Against this backdrop, the technological route of producing fuels (such as methanol and hydrocarbons) through catalytic hydrogenation of carbon dioxide is of particular importance because it simultaneously achieves fuel production that "turns waste into treasure" and the resource utilization of carbon dioxide. Methanol, as one of the important products of carbon dioxide hydrogenation, has attracted much attention. It is not only a high-energy-density fuel but also an important feedstock for converting into olefins, gasoline, and other downstream bulk chemicals.

[0003] Developing highly active, selective, and stable low-pressure catalysts is a core scientific challenge in the field of carbon dioxide hydrogenation to methanol. Currently, the potential industrialization route for this reaction remains a thermocatalytic process under extremely high pressure, which suffers from high energy consumption, demanding equipment requirements, and significant safety risks. Designing suitable catalysts to achieve highly active and selective carbon dioxide hydrogenation to methanol under low pressure is of great significance. Most reported catalysts at low pressure typically only yield low-value products CO and CH4. Commercial Cu-ZnO-Al2O3 catalysts show significant advantages over other catalysts in low-pressure carbon dioxide hydrogenation to methanol, but performance optimization of this catalyst itself has reached a bottleneck.

[0004] Chinese patent document CN115007160A discloses a catalyst for the hydrogenation of carbon dioxide to methanol, its preparation method, and its application. The catalyst prepared by this invention is an amorphous alloy catalyst powder comprising a main component and auxiliary components. The main component includes copper, zinc, zirconium, and aluminum, while the auxiliary components include at least two metals selected from platinum, palladium, cerium, manganese, and titanium. The catalyst is obtained by ball milling the corresponding raw materials in an inert gas atmosphere. This catalyst can carry out the hydrogenation of carbon dioxide to methanol reaction at low temperature and low pressure.

[0005] Chinese patent document CN117299136A discloses a method for preparing a low-sodium, high-activity copper-based methanol synthesis catalyst. This invention uses Cu(NO3)2, Zn(NO3)2, and Zr(NO3)4, along with an alkaline precipitant, as raw materials to prepare a catalyst precursor. A low-sodium alumina support is then added, followed by washing, filtration, drying, and calcination to obtain the catalyst precursor. After washing, drying, and molding, the finished low-sodium, high-activity copper-based methanol synthesis catalyst is obtained. This catalyst is suitable for methanol production from syngas containing CO, CO2, and H2, and is particularly suitable for low-temperature, low-pressure methanol synthesis plants.

[0006] Although the aforementioned patents can achieve the preparation of methanol from CO2 at low temperature and low pressure, they have problems such as a wide variety of raw materials and high complexity of process control. Summary of the Invention

[0007] To address the issues of low activity and selectivity in existing low-pressure methanol catalysts, this invention utilizes an ammonia-assisted magnesium silicide reduction method to prepare a carbon dioxide hydrogenation to methanol catalyst. Silicon is introduced into the Cu-ZnO catalyst system in a novel way, enabling high-activity and high-selectivity catalytic hydrogenation of carbon dioxide to methanol under conditions of 0~0.5 MPa (relative to atmospheric pressure).

[0008] The specific technical solution adopted is as follows:

[0009] A catalyst for the hydrogenation of carbon dioxide to methanol is prepared by an ammonia-assisted magnesium silicide reduction method. The specific preparation steps include:

[0010] Copper nitrate and zinc nitrate were mixed and dissolved in an alcohol solvent, and ammonia was added. Then magnesium silicide was added to construct a reaction system. The reaction system was mixed and reacted at 30-70 °C for 2-8 h. The resulting product solution was centrifuged, washed and dried. The dried product was first treated in an air atmosphere at 0-850 °C for 1-8 h, and then calcined in a reducing atmosphere at 300-600 °C for 1-8 h to obtain the carbon dioxide hydrogenation to methanol catalyst.

[0011] A solution obtained by dissolving a mixture of copper nitrate and zinc nitrate in an alcohol solvent has a copper concentration of 0.05–0.3 mol / L. -1 The concentration of zinc was 0.1–0.7 mol / L. -1 ;

[0012] The volume ratio of alcohol solvent to ammonia is 1:0.05~0.2;

[0013] The molar ratio of magnesium silicide to copper nitrate is 1:0.5~2.

[0014] This invention utilizes an ammonia-assisted magnesium silicide reduction method to introduce silicon into the Cu-ZnO catalyst system in a novel way (unlike previous methods that only used it as an impregnation support or coating layer). The aim is to further optimize the performance of the catalyst system through structural and surface modifications. By organically combining two-dimensional silicon, copper, and zinc oxide, a high-activity, high-selectivity, and high-stability low-pressure methanol catalyst for carbon dioxide hydrogenation is obtained.

[0015] Specifically, the carbon dioxide hydrogenation to methanol catalyst contains copper, zinc, oxygen, silicon, nitrogen and magnesium. The sample with the highest activity, as measured by ICP, contained 12.44 wt% and 47.4 wt% of the key elements copper and zinc, respectively. Copper exists in the form of crystal grains with a size of 15-20 nm.

[0016] Optionally, ethanol can be used as the alcohol solvent.

[0017] Optionally, the mass concentration of ammonia water is 25~28 wt%. Experiments have shown that ammonia water is one of the essential raw materials of this invention, which helps to improve the catalytic activity of the product catalyst.

[0018] Preferably, the reaction system is mixed and reacted at 40-60 °C for 3-5 h under a stirring speed of 200-600 rpm.

[0019] Optionally, the reducing atmosphere is a hydrogen atmosphere or a mixture of hydrogen and an inert gas (Ar or N2).

[0020] More preferably, the dried product is first treated in an air atmosphere at 400-850 °C for 2-4 h, and then calcined in a reducing atmosphere at 300-400 °C for 2-4 h.

[0021] The present invention also provides a method for producing methanol by hydrogenation of carbon dioxide, utilizing the aforementioned catalyst for the hydrogenation of carbon dioxide to methanol.

[0022] Specifically, the method for producing methanol by carbon dioxide hydrogenation includes the following steps: passing a feed gas containing CO2 and H2 into a reactor containing the catalyst for producing methanol by carbon dioxide hydrogenation, reacting, and obtaining methanol.

[0023] Furthermore, CO2 and H2 are used as reactants, and N2 as an internal standard and equilibrium gas. The flow rate ratio (molar ratio) of CO2, H2, and N2 is 2:6:1~2, and the total gas flow rate is 10~18 mL / min. -1 The reaction temperature is 150~300 ℃, and the reaction pressure is 0~0.5 MPa relative to atmospheric pressure.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] This invention focuses on the cutting-edge directions of carbon dioxide emission reduction and high-value fuel production. Addressing the key scientific problems faced in the application of low-pressure methanol catalysts, it utilizes a special form of silicon combined with copper and zinc oxide, and employs an ammonia-assisted magnesium silicide reduction method to construct a novel Cu-Zn-O-Si intermediate. This yields a catalyst with strong metal-support interaction, small-sized copper particles, and abundant copper-zinc oxide interfaces, thereby achieving highly active, highly selective, and highly stable catalytic hydrogenation of carbon dioxide to methanol.

[0026] The catalyst prepared by the ammonia-assisted magnesium silicide reduction method of this invention exhibits performance far superior to catalysts prepared under similar conditions by conventional impregnation methods and magnesium silicide reduction methods alone. For example, the methanol product rate of the catalyst prepared by the ammonia-assisted magnesium silicide reduction method at 250°C and atmospheric pressure (0 MPa) can reach 63.19 μmol g / L normalized to the total catalyst mass. cat -1 h -1 The catalysts prepared by conventional impregnation and magnesium silicide reduction alone produced only 11.3 μmol g of methanol under the same conditions. cat -1 h -1 and 14.1 μmol g cat -1 h -1 .

[0027] The carbon dioxide hydrogenation low-pressure methanol catalyst prepared by this invention has significantly improved methanol product rate and methanol selectivity when normalized to copper compared with commercial Cu-ZnO-Al2O3 (CZA) catalyst. Attached Figure Description

[0028] Figure 1 The images shown are characterization images of the CZS-1.1Ar catalyst in Example 1. In the image, A is a TEM image, B is a STEM image, and CG correspond to the elemental distribution of copper, zinc, oxygen, silicon, and nitrogen in the outline of B, respectively.

[0029] Figure 2 The catalysts used in Example 1 (CZS-1.1Ar), Comparative Example 1 (CZS-r), and Comparative Example 2 (CZS) are CZS-1.1Ar catalysts. im XRD pattern of -1.1Ar catalyst.

[0030] Figure 3 The catalysts used in Example 1 (CZS-1.1Ar), Comparative Example 1 (CZS-r), and Comparative Example 2 (CZS) are CZS-1.1Ar catalysts. im -1.1Ar catalyst and CZSM in Comparative Example 3 im-1.1 Comparison of the activity of Ar catalyst in the hydrogenation of carbon dioxide to methanol at atmospheric pressure (0 MPa).

[0031] Figure 4 The graphs show a comparison of the activity, selectivity, and stability of the CZS-1.1Ar catalyst in Example 1 and the commercial CZA catalyst in Comparative Example 4 in the reaction of carbon dioxide hydrogenation to methanol at atmospheric pressure (0 MPa). In the graphs, A is a comparison of the methanol product rates of the two samples during the continuous reaction, and B is a comparison of the methanol selectivity of the two samples during the continuous reaction.

[0032] Figure 5 The graphs show a comparison of the activity and selectivity of the CZS-1.1Ar catalyst in Example 1 and the commercial CZA catalyst in Comparative Example 4 in the low-pressure (0.5 MPa) carbon dioxide hydrogenation to methanol reaction. In the graphs, A is a comparison of the methanol product rate of the two samples at different temperatures, and B is a comparison of the methanol selectivity of the two samples at different temperatures. Detailed Implementation

[0033] To make the objectives, features, and advantages of this invention more apparent and understandable, a detailed description is provided below through specific embodiments. Many specific details are set forth in the following description to provide a thorough understanding of the invention. However, the invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below. Technical features in various embodiments of the invention can be combined appropriately without mutual conflict.

[0034] Unless otherwise specified, the operating methods in the following examples are generally performed under conventional conditions or as recommended by the manufacturer. Contents not described in detail in this specification are prior art known to those skilled in the art. Unless otherwise specified, the experimental materials used in the examples below can be purchased from conventional biochemical reagent companies.

[0035] In the examples and comparative examples, copper nitrate trihydrate, zinc nitrate hexahydrate, ammonia, magnesium silicide, commercial silica support, and commercial copper-zinc oxide-alumina (CZA) catalyst were all commercially available. The amounts of the reaction raw materials used in the examples and comparative examples can be scaled up proportionally.

[0036] Example 1

[0037] (1) Weigh 0.2233 g of copper nitrate trihydrate and 1.002 g of zinc nitrate hexahydrate and dissolve them in 10 mL of anhydrous ethanol. Add 1.1 mL of ammonia water and shake well. Then quickly add 0.1 g of magnesium silicide and react in a shaker (50 ℃, 400 rpm) for 4 h. After centrifugation to remove the supernatant, the mixture is washed once with ethanol by centrifugation. Finally, remove the supernatant and vacuum dry (centrifugation conditions are 10000 rpm, 6 min). The dried powder is calcined in air atmosphere (850 ℃, 2 h) and H2 atmosphere (300 ℃, 2 h) respectively. The catalyst sample obtained is denoted as CZS-1.1Ar (where CZS represents that its main components are Cu, ZnO and SiO). x 1.1A indicates that 1.1 mL of ammonia was added to the sample, and r indicates that the sample is a reduced sample. The naming method for other cases follows a similar rule.

[0038] (2) The reaction of carbon dioxide hydrogenation to methanol was carried out in a mobile phase reaction apparatus (atmospheric pressure 0 MPa or low pressure 0.5 MPa, relative to atmospheric pressure). The reaction conditions at atmospheric pressure (0 MPa) were as follows: 36 mg of CZS-1.1Ar was placed in the quartz tube of the tubular reactor, both ends were plugged with quartz wool, and CO2 and H2 were introduced as reaction gases, with N2 as the internal standard and equilibrium gas. The reaction gas ratio was CO2: H2: N2 = 2: 6: 1 (molar ratio), and the total flow rate was 18 mL / min. -1 The reaction temperature was set at 150–300 °C, and the products were monitored online by gas chromatography. The low-pressure (0.5 MPa) reaction conditions were as follows: 18 mg of CZS-1.1Ar was placed in the quartz tube of a tubular reactor, both ends were plugged with quartz wool, and CO2 and H2 were introduced as reaction gases, with N2 used as an internal standard and equilibrium gas. The reaction gas ratio was CO2:H2:N2 = 2:6:2 (molar ratio), and the total flow rate was 10 mL / min. -1 The reaction temperature was set to 150~300 ℃, and the product was monitored online by gas chromatography.

[0039] The CZS-1.1Ar catalyst prepared in this embodiment has an overall sheet-like nanostructure, in which copper, zinc, oxygen, silicon, and nitrogen are uniformly distributed on the sheet-like outline. Figure 1 The copper grains in CZS-1.1Ar are relatively small, with no obvious large particles, possibly due to the improved dispersion of copper by the copper-ammonia complex during synthesis. XRD results, calculated using the Scherrer equation, show that the Cu grain size is 16.7 nm, significantly smaller than that in Comparative Examples 1-2. Figure 2Catalytic results showed that CZS-1.1Ar can catalyze the hydrogenation of carbon dioxide to methanol under normal pressure. At a reaction temperature of 250 °C, the methanol product rate (normalized to the total catalyst mass) was 63.19 μmol g. cat -1 h -1 This is much higher than that of comparative examples 1-3. Figure 3 ICP testing results showed that the copper mass fraction of CZS-1.1Ar was 12.44%, therefore the methanol product rate of CZS-1.1Ar normalized to copper reached 508 μmol g. Cu -1 h -1 It is far superior to commercial copper-zinc oxide-alumina (CZA) catalysts under the same conditions (~160 μmol g). Cu -1 h -1 ), and can remain stable for at least 33 hours without inactivation ( Figure 4 (A and B in the original text). Due to the limitations of atmospheric pressure reaction kinetics, the methanol selectivity of CZS-1.1Ar at 250℃ is only about 6%, but it is still much higher than that of the commercial CZA catalyst (0.7%). Applying a very small pressure can significantly improve the methanol product rate and selectivity of the CZS-1.1Ar catalyst. Here, we tested the catalytic performance of CZS-1.1Ar in the catalytic hydrogenation of carbon dioxide to methanol under low pressure conditions using a reaction condition of 0.5 MPa as an example. Figure 5 (A and B in the text). The results show that CZS-1.1Ar can reach 973 μmol g at 200℃. Cu -1 h -1 The methanol production rate was almost identical to that of commercial CZA (1027 μmol g). Cu -1 h -1 However, CZS-1.1Ar's methanol selectivity (56.7%) was significantly higher than that of commercial CZA (23.1%). As the temperature increased further, CZS-1.1Ar's methanol product rate surpassed that of commercial CZA, while maintaining a high selectivity. Compared to commercial CZA, the advantages of CZS-1.1Ar in methanol product rate and selectivity became increasingly apparent with rising temperature (CZS-1.1Ar still maintained 30% methanol selectivity at 230 °C, while the methanol selectivity of commercial CZA had decreased to 7.6%. At this temperature, the methanol product rate of CZS-1.1Ar normalized to copper was 1.6 times that of commercial CZA).

[0040] Furthermore, the preparation method of the carbon dioxide hydrogenation to methanol catalyst listed in the above steps has optimal parameters. During the experiment, the present invention also optimized the parameters of each precursor of the catalyst within a certain range. During the optimization process, the feeding range of Cu precursor was 1 to 3 times (mass ratio) of the above steps, the feeding range of Zn precursor was 0.3 to 2 times (mass ratio) of the above steps, and the feeding range of ammonia water was 0.5 to 1.6 times of the above steps. The methanol product rate of the obtained catalyst was about 8% to 100% of that of the carbon dioxide hydrogenation to methanol catalyst prepared in the above steps.

[0041] Comparative Example 1

[0042] (1) Weigh 0.2233 g of copper nitrate trihydrate and 1.002 g of zinc nitrate hexahydrate and dissolve them in 10 mL of anhydrous ethanol. Then quickly add 0.1 g of magnesium silicide and react in a shaker (50 ℃, 400 rpm) for 4 h. After centrifugation to remove the supernatant, the mixture was washed once with ethanol by centrifugation. Finally, the supernatant was removed and the mixture was vacuum dried (centrifugation conditions were 10000 rpm, 6 min). The dried powder was calcined in air atmosphere (850 ℃, 2 h) and H2 atmosphere (300 ℃, 2 h) respectively. The resulting catalyst sample was denoted as CZS-r.

[0043] (2) The reaction of carbon dioxide hydrogenation to methanol was carried out in a mobile phase reaction apparatus (atmospheric pressure 0 MPa). The reaction conditions at atmospheric pressure were as follows: 36 mg of CZS-r was placed in the quartz tube of the tubular reactor, both ends were plugged with quartz wool, and CO2 and H2 were introduced as reaction gases, with N2 as the internal standard and equilibrium gas. The reaction gas ratio was CO2:H2:N2 = 2:6:1 (molar ratio), and the total flow rate was 18 mL / min. -1 The reaction temperature was set to 150~300 ℃, and the product was monitored online by gas chromatography.

[0044] The difference between this comparative example and Example 1 is that ammonia was not added during the catalyst synthesis process, thus verifying the unique role of ammonia in the preparation method involved in this invention. The catalytic activity of CZS-r is much lower than that of CZS-1.1Ar ( Figure 3 This may be due to its larger copper size compared to CZS-1.1Ar. Figure 2 ).

[0045] Comparative Example 2

[0046] (1) Under stirring conditions (200 r / min, room temperature), 0.3466 g of copper nitrate trihydrate and 1.5856 g of zinc nitrate hexahydrate were dissolved in 20 mL of anhydrous ethanol, and 2.2 mL of ammonia water was added (while stirring). Then, 0.2 g of commercial SiO2 support was quickly added (while stirring), and the temperature was raised to 80 °C until the solution was completely evaporated. The evaporated product was transferred to a vacuum drying oven for vacuum drying. The dried powder was then calcined in air atmosphere (850 °C, 2 h) and H2 atmosphere (300 °C, 2 h) respectively. The resulting catalyst sample was denoted as CZS. im -1.1Ar.

[0047] (2) The reaction of carbon dioxide hydrogenation to methanol was carried out in a mobile phase reaction apparatus (atmospheric pressure 0 MPa). The reaction conditions at atmospheric pressure were as follows: 36 mg of CZS was taken. im -1.1 Ar was placed in a quartz tube of a tubular reactor, with both ends plugged with quartz wool. CO2 and H2 were introduced as reactant gases, and N2 was used as an internal standard and equilibrium gas. The reactant gas ratio was CO2:H2:N2 = 2:6:1 (molar ratio), and the total flow rate was 18 mL / min. -1 The reaction temperature was set to 150~300 ℃, and the product was monitored online by gas chromatography.

[0048] The difference between this comparative example and Example 1 is that the catalyst was synthesized using a conventional impregnation method instead of the magnesium silicide reduction method, thus demonstrating the effectiveness of the magnesium silicide reduction method provided by this invention. The feed ratio in this comparative example was determined based on the consistency between the theoretical copper and zinc loadings and the actual copper and zinc loadings of CZS-1.1Ar. im The catalytic activity of -1.1Ar is much lower than that of CZS-1.1Ar ( Figure 3 This may be because it is different from CZS. im -1.1Ar larger copper size ( Figure 2 Here, in conjunction with Comparative Example 1, it is shown that both ammonia and magnesium silicide reduction are indispensable for the catalyst preparation method involved in this invention. Only the magnesium silicide reduction method assisted by ammonia can obtain a highly active catalyst for the hydrogenation of carbon dioxide to methanol.

[0049] Comparative Example 3

[0050] (1) Under stirring conditions (200 r / min, room temperature), 0.3466 g of copper nitrate trihydrate, 1.5856 g of zinc nitrate hexahydrate and 1.0084 g of magnesium nitrate hexahydrate were dissolved in 20 mL of anhydrous ethanol. 2.2 mL of ammonia water was added (while stirring), followed by the rapid addition of 0.2 g of commercial SiO2 support (while stirring). The temperature was raised to 80 °C until the solution was completely evaporated. The evaporated product was transferred to a vacuum drying oven for vacuum drying. The dried powder was then calcined in air (850 °C, 2 h) and H2 atmosphere (300 °C, 2 h) respectively. The resulting catalyst sample was designated CZSM. im -1.1Ar.

[0051] (2) The reaction of carbon dioxide hydrogenation to methanol was carried out in a mobile phase reaction apparatus (atmospheric pressure 0 MPa). The reaction conditions at atmospheric pressure were as follows: 36 mg of CZSM was taken. im -1.1 Ar is placed in a quartz tube of a tubular reactor, with both ends plugged with quartz wool. CO2 and H2 are introduced as reactant gases, and N2 is used as an internal standard and equilibrium gas. The reactant gas ratio is CO2:H2:N2 = 2:6:1 (molar ratio), and the total flow rate is 18 mL / min. -1 The reaction temperature was set to 150~300 ℃, and the product was monitored online by gas chromatography.

[0052] The difference between this comparative example and Comparative Example 2 is that magnesium nitrate hexahydrate was added during the catalyst synthesis process. The CZS-1.1Ar in Example 1 contains residual magnesium. Catalytic results indicate that CZSM... im The catalytic activity of -1.1Ar is much lower than that of CZS-1.1Ar, and compared to CZS... im -1.1Ar showed no significant improvement ( Figure 3 This further illustrates the necessity of using the ammonia-assisted magnesium silicide reduction method to prepare a catalyst for the hydrogenation of carbon dioxide to methanol.

[0053] Comparative Example 4

[0054] (1) The material used in this comparative example is a commercial copper-zinc oxide-alumina (CZA) catalyst. The catalyst sample obtained by calcining the purchased CZA in H2 atmosphere (300 °C, 2h) was subjected to catalytic testing.

[0055] (2) The reaction of carbon dioxide hydrogenation to methanol was carried out in a mobile phase reaction apparatus (atmospheric pressure 0 MPa or low pressure 0.5 MPa, relative to atmospheric pressure). The atmospheric pressure reaction conditions were as follows: 36 mg of commercial CZA catalyst was placed in the quartz tube of the tubular reactor, and both ends were plugged with quartz wool. CO2 and H2 were introduced as reaction gases, and N2 was used as internal standard and equilibrium gas. The reaction gas ratio was CO2:H2:N2 = 2:6:1 (molar ratio), and the total flow rate was 18 mL / min. -1 The reaction temperature was set at 150–300 °C, and the products were monitored online by gas chromatography. The low-pressure reaction conditions were as follows: 18 mg of commercial CZA catalyst was placed in the quartz tube of a tubular reactor, both ends were plugged with quartz wool, and CO2 and H2 were introduced as reactant gases, with N2 used as an internal standard and equilibrium gas. The reactant gas ratio was CO2:H2:N2 = 2:6:2 (molar ratio), and the total flow rate was 10 mL / min. -1 The reaction temperature was set to 150~300 ℃, and the product was monitored online by gas chromatography.

[0056] As mentioned above, such as Figure 4 A, B and Figure 5 As shown in A and B, the CZS-1.1Ar catalyst prepared in Example 1 is significantly superior to the commercial CZA catalyst in terms of methanol selectivity, and its methanol product rate at 230~250 °C is also significantly better than that of the commercial CZA catalyst.

[0057] The embodiments described above provide a detailed explanation of the technical solutions of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, additions, or similar substitutions made within the scope of the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A catalyst for the hydrocarbon of carbon dioxide to methanol, characterized in that, The carbon dioxide hydrogenation methanol catalyst is prepared by using an ammonia-assisted magnesium silicide reduction method, and the specific preparation steps include: The copper nitrate and zinc nitrate are mixed and dissolved in an alcohol solvent, ammonia water is added, and then magnesium silicide is added to construct a reaction system, the reaction system is mixed at 30-70 DEG C for 2-8 h, then the obtained product solution is centrifuged, washed and dried, the dried product is first placed in an air atmosphere at 0-850 DEG C for 1-8 h, and then placed in a reducing atmosphere at 300-600 DEG C for 1-8 h to obtain the carbon dioxide hydrogenation methanol catalyst. The concentration of copper element in the solution obtained by mixing copper nitrate and zinc nitrate in an alcohol solvent is 0.05-0.3 mol / L -1 , and the concentration of zinc element is 0.1-0.7 mol / L -1 . The volume ratio of the alcohol solvent to the ammonia water is 1:0.05-0.

2. The molar ratio of the added amount of magnesium silicide to the copper nitrate is 1:0.5-2.

2. The carbon dioxide hydrogenation to methanol catalyst of claim 1, wherein, The carbon dioxide hydrogenation methanol catalyst contains copper, zinc, oxygen, silicon, nitrogen and magnesium elements, wherein the copper exists in the form of crystal grains, and the size of the copper crystal grains is 15-20 nm.

3. The carbon dioxide hydrogenation to methanol catalyst of claim 1, wherein, The alcohol solvent is selected from ethanol.

4. The catalyst for the methanol synthesis from carbon dioxide and hydrogen according to claim 1, characterized in that, The mass concentration of the ammonia water is 25-28 wt%.

5. The catalyst for the methanol synthesis from carbon dioxide and hydrogen according to claim 1, characterized in that, The reaction system is mixed at 40-60 DEG C under the condition of a stirring speed of 200-600 rpm for 3-5 h.

6. The catalyst for the methanol synthesis from carbon dioxide and hydrogen according to claim 1, characterized in that, The reducing atmosphere is a hydrogen atmosphere or a mixed atmosphere of hydrogen and an inert gas.

7. The carbon dioxide hydrogenation to methanol catalyst of claim 6, wherein, The dried product is first placed in an air atmosphere at 400-850 DEG C for 2-4 h, and then placed in a reducing atmosphere at 300-400 DEG C for 2-4 h.

8. A process for the hydrocarbon of carbon dioxide to methanol, characterized in that, The carbon dioxide hydrogenation methanol catalyst according to any one of claims 1-7 is used.

9. The method of carbon dioxide hydrogenation to methanol according to claim 8, c h a r a c t e r i z e d b y, The method for carbon dioxide hydrogenation methanol includes the following steps: passing a raw material gas containing CO2 and H2 into a reactor containing the carbon dioxide hydrogenation methanol catalyst to react, and obtaining methanol.

10. The process for the methanol synthesis from carbon dioxide and hydrogen according to claim 9, characterized in that, CO2 and H2 as reaction gas, N2 as internal standard and balance gas, flow rate ratio of CO2, H2 and N2 is 2:6:1~2, total flow rate of gas is 10~18 mL / min -1 , reaction temperature is 150~300 ℃, reaction pressure is 0~0.5 MPa relative to atmospheric pressure.

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