Copper-based catalyst for synthesizing methanol from CO2 and preparation method of copper-based catalyst

Abstract

The invention discloses a copper-based catalyst for synthesizing methanol from CO2 and a preparation method of the copper-based catalyst. The copper-based catalyst comprises the following components: a) sodium metaaluminate; b): hexadecyl trimethyl ammonium bromide; c): aluminum nitrate; d): zirconium nitrate; e): deionized water; f): aluminum sulfate; g): aluminum chloride; h): copper nitrate; according to the copper-based catalyst for synthesizing methanol from CO2 and the preparation method of the copper-based catalyst, zirconium-doped boehmite is prepared in advance and roasted to obtain zirconium-doped aluminum oxide with hierarchical pores, the zirconium-doped aluminum oxide serves as a carrier and is subjected to deposition and precipitation with the active component copper and zinc, and finally the catalyst which is high in activity and good in stability in the CO2 hydrogenation reaction is obtained. The zirconium-doped alumina carrier obtained by roasting zirconium-doped boehmite prepared in advance has hierarchical pores, high specific surface area, high-temperature stability and sintering resistance, is beneficial to uniform dispersion of copper-zinc active components, enhances the stability of the copper-zinc active components, inhibits migration and aggregation of the copper-zinc active components, and prolongs the service life of the catalyst.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of catalysts, in particular to a copper-based catalyst for synthesizing methanol from CO2 and a preparation method thereof. BACKGROUND

[0002] Carbon dioxide (CO2) is an important carbon resource on earth and also the main gas causing the greenhouse effect. As a cheap, abundant, green, non-toxic and renewable C1 resource, CO2 can be effectively reduced in the atmosphere by catalytic hydrogenation to produce methanol, which is a valuable chemical and fuel, and thus is of great significance to solve environmental problems and alleviate energy crisis. Therefore, it has become one of the most concerned research directions in the utilization of CO2 resources.

[0003] Copper-based catalysts are the mainstream catalysts for the synthesis of methanol from CO2 hydrogenation, and reasonable design and development of the catalysts are crucial for efficient utilization of CO2.

[0004] Co-precipitation method has the advantages of simple operation, controllable process, stable performance and industrial production, and thus is the most commonly used preparation method. Current copper-zinc-aluminum (Cu-Zn-Al) catalysts in the industry show important value in the synthesis of methanol from CO2 hydrogenation, but still have the following main shortcomings.

[0005] Firstly, copper-zinc-aluminum catalysts are prone to sintering under high-temperature reaction conditions, leading to agglomeration of active components (such as copper grains), decrease of specific surface area and porosity, and thus reduction of catalytic activity and stability.

[0006] Secondly, the catalysts have poor adaptability to CO2 hydrogenation reaction. When traditional copper-zinc-aluminum catalysts are directly used for the synthesis of methanol from CO2 hydrogenation, the catalyst surface is prone to carbon deposition or structural change due to the influence of reaction by-products water, leading to low CO2 conversion rate and methanol selectivity.

[0007] Thirdly, structural defects affect activity and selectivity. Crystal structure defects (such as point defects and dislocations) of copper-zinc-aluminum catalysts may affect the distribution of active sites. For example, too high defect concentration may lead to insufficient exposure of active sites or cause side reactions (such as methane generation), reducing the selectivity of target products. In addition, when aluminum is used as the carrier, spinel structure is easily formed, which may wrap the copper active phase and limit its exposure.

[0008] Fourthly, the catalysts have insufficient low-temperature activity. Under low-temperature reaction conditions, the activity of copper-zinc-aluminum catalysts is significantly reduced, and the low-temperature performance needs to be improved by adding additives (such as Zr and Ce) or optimizing the carrier structure.

[0009] In summary, the copper-based catalyst is applied to the synthesis of methanol from CO2, due to the poor stability of the catalyst, the inevitable migration and aggregation of the active component will occur, which will lead to the reduction of the activity and service life of the catalyst. This is very unfavorable for the industrial utilization of CO2 to produce methanol, and therefore it is necessary to prepare a copper-based catalyst with high stability and good activity. SUMMARY

[0010] This section is intended to summarize some aspects of the embodiments of the present application and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of the specification of the present application in order to avoid obscuring the purpose of this section, the abstract and the title, and such simplifications or omissions cannot be used to limit the scope of the present application.

[0011] 1. Technical problems to be solved:

[0012] In order to solve the existing problems in the prior art, the present application is proposed.

[0013] Therefore, the purpose of the present application is to provide a copper-based catalyst for the synthesis of methanol from CO2 and a preparation method thereof. The catalyst uses copper and zinc as the active component, and aluminum and zirconium as the sintering-resistant carrier for inhibiting the migration and aggregation of the active component. By changing the preparation method of the catalyst, the aluminum and zirconium components are first precipitated and gelled, and a zirconium-doped boehmite precursor with hierarchical pores is prepared using a template agent. The precursor is calcined to obtain a high-surface-area hierarchical-pore zirconium-doped alumina carrier with higher stability and better dispersion of copper and zinc. Then, the active components copper and zinc are deposited on the carrier to obtain a novel copper-based catalyst suitable for the hydrogenation of CO2 to methanol. The catalyst prepared by this method has high selectivity and stability.

[0014] 2. Technical solutions:

[0015] In order to solve the above technical problems, according to one aspect of the present application, the present application provides the following technical solutions:

[0016] A copper-based catalyst for the synthesis of methanol from CO2, comprising the following components:

[0017] a) sodium alumininate;

[0018] b) hexadecyl trimethyl ammonium bromide;

[0019] c) aluminum nitrate;

[0020] d) zirconium nitrate;

[0021] e) deionized water;

[0022] f) aluminum sulfate;

[0023] g) Aluminium chloride;

[0024] h) Copper nitrate;

[0025] i) Zinc nitrate.

[0026] As a preferred scheme of the copper-based catalyst for synthesizing methanol from CO2, in the present application, the molar ratio of the amount of addition of cetyltrimethylammonium bromide to the molar ratio of zirconium and aluminum is (CTAB: Zr-Al) = (1:20-100) in parts by proportion.

[0027] As a preferred scheme of the preparation method of the copper-based catalyst for synthesizing methanol from CO2, in the present application, sodium aluminate (NaAlO2) and cetyltrimethylammonium bromide (CTAB) are dissolved in deionized water, aluminum nitrate (Al(NO3)3·9H2O) and zirconium nitrate (Zr(NO3)4·5H2O) are dissolved in deionized water, a nucleation reactor is started, the prepared two solutions are injected, after a period of time, the slurry is taken out, placed on a constant-temperature magnetic stirrer, and the pH is adjusted, then aging treatment is carried out, after centrifugation and washing, the product is dried in an oven and calcined in a muffle furnace to obtain zirconium-doped boehmite.

[0028] As a preferred scheme of the preparation method of the copper-based catalyst for synthesizing methanol from CO2, in the present application, the mixed slurry is placed on a constant-temperature magnetic stirrer, and the pH is adjusted to 8.8 by dilute nitric acid.

[0029] As a preferred scheme of the preparation method of the copper-based catalyst for synthesizing methanol from CO2, in the present application, in the zirconium-doped boehmite, the molar ratio of zirconium to aluminum is (Zr:Al) = 0-25%:75%-100%.

[0030] As a preferred scheme of the preparation method of the copper-based catalyst for synthesizing methanol from CO2, in the present application, the zirconium-doped alumina carrier is prepared from the precursor boehmite using sodium aluminate as a precipitant and an aluminum source, one of aluminum nitrate, aluminum sulfate, and aluminum chloride as another aluminum source, and zirconium nitrate as a zirconium source.

[0031] As a preferred scheme of the preparation method of the copper-based catalyst for synthesizing methanol from CO2, in the present application, the carrier material is placed in deionized water (solid-liquid ratio = 1:50), ultrasonically dispersed for 2-3 h, added to a reaction kettle, stirred at high speed, and kept at a constant temperature of 50-65°C.

[0032] As a preferred scheme of the preparation method of the copper-based catalyst for synthesizing methanol from CO2, the concentration of the metal salt solution and the alkali solution is 1M, and they are added into the reactor in a parallel flow mode to keep the pH value in the reactor at 8.

[0033] As a preferred scheme of the preparation method of the copper-based catalyst for synthesizing methanol from CO2, the copper-based catalyst is prepared by a step-by-step precipitation method, i.e., first, a Zr-doped alumina carrier with a large pore volume and a high specific surface area is prepared from boehmite, and then the copper-zinc component is deposited on the carrier, and the metal molar ratio of the catalyst is (Cu:Zn:Al-Zr) = 50%-70%:20%-30%:5%-20%.

[0034] 3. Beneficial effects:

[0035] Compared with the prior art, the present application has the beneficial effects that:

[0036] The copper-based catalyst for synthesizing methanol from CO2 and the preparation method thereof have the following beneficial effects: the Zr-doped boehmite is prepared in advance, the Zr-doped alumina carrier with a multi-level pore, a high specific surface area, high-temperature stability and sintering resistance is obtained after calcination, which is beneficial to the uniform dispersion of the copper-zinc active component, enhances the stability of the copper-zinc active component, inhibits the migration and aggregation of the copper-zinc active component, and prolongs the service life of the catalyst. DETAILED DESCRIPTION

[0037] The present application provides an embodiment of a copper-based catalyst for synthesizing methanol from CO2 and a preparation method thereof, which comprises the following steps:

[0038] The copper-based catalyst for synthesizing methanol from CO2 in the embodiment comprises the following components:

[0039] a) sodium alumininate;

[0040] b) hexadecyl trimethyl ammonium bromide;

[0041] c) aluminum nitrate;

[0042] d) zirconium nitrate;

[0043] e) deionized water;

[0044] f) aluminum sulfate;

[0045] g) aluminum chloride;

[0046] h) copper nitrate;

[0047] i) Zinc nitrate.

[0048] It is worth mentioning that the molar ratio of the amount of cetyltrimethylammonium bromide added to zirconium and aluminum in proportion is (CTAB: Zr-Al) = (1:20-100).

[0049] Next, sodium aluminate (NaAlO2) and cetyltrimethylammonium bromide (CTAB) are dissolved in deionized water, aluminum nitrate (Al(NO3)3·9H2O) and zirconium nitrate (Zr(NO3)4·5H2O) are dissolved in deionized water, the nucleation reactor is started, the prepared two solutions are injected, after a period of time, the slurry is taken out, placed on a constant temperature magnetic stirrer, and the pH is adjusted, then aging treatment is carried out, after centrifugation and washing, the product is placed in an oven for drying and calcined in a muffle furnace to obtain zirconium-doped boehmite.

[0050] At the same time, the slurry is mixed on a constant temperature magnetic stirrer, and the pH is adjusted to 8.8 by dilute nitric acid.

[0051] Further, in the zirconium-doped boehmite, the molar ratio of zirconium to aluminum is (Zr:Al) = 0-25%:75%-100%.

[0052] Next, the zirconium-doped alumina carrier is prepared from the precursor boehmite using sodium aluminate as a precipitator and an aluminum source, one of aluminum nitrate, aluminum sulfate, and aluminum chloride as another aluminum source, and zirconium nitrate as a zirconium source.

[0053] Further, the carrier material is placed in deionized water (solid-liquid ratio = 1:50), ultrasonically dispersed for 2-3 hours, added to the reaction kettle, and stirred at high speed while maintaining a constant temperature of 50-65°C.

[0054] At the same time, the concentration of the metal salt solution and the alkali solution is 1M, and they are added to the reaction kettle in a concurrent manner while maintaining the pH value in the reaction kettle at 8.

[0055] Finally, the copper-based catalyst is prepared by a step-by-step precipitation method, first preparing a zirconium-doped alumina carrier with a large pore volume and a high specific surface area from boehmite, and then depositing copper and zinc components onto the carrier, with the metal molar ratio of the catalyst being (Cu:Zn:Al-Zr) = 50%-70%:20%-30%:5%-20%.

[0056] Example 1:

[0057] A copper-based catalyst for synthesizing methanol from CO2 includes the following components:

[0058] a) Sodium aluminate;

[0059] b) Cetyltrimethylammonium bromide;

[0060] c) Aluminum nitrate;

[0061] d) Zirconium nitrate;

[0062] e) Deionized water;

[0063] f) Aluminum sulfate;

[0064] g) Aluminum chloride;

[0065] h) Copper nitrate;

[0066] i) Zinc nitrate.

[0067] It is worth mentioning that the molar ratio of the amount of cetyltrimethylammonium bromide added to zirconium and aluminum in proportion is (CTAB: Zr-Al) = (1:20-100).

[0068] Next, sodium aluminate (NaAlO2) and cetyltrimethylammonium bromide (CTAB) are dissolved in deionized water, aluminum nitrate (Al(NO3)3·9H2O) and zirconium nitrate (Zr(NO3)4·5H2O) are dissolved in deionized water, the nucleation reactor is started, the prepared two solutions are injected, after a period of time, the slurry is taken out, placed on a constant temperature magnetic stirrer, and the pH is adjusted, then aging treatment is carried out, after centrifugation and washing, the product is placed in an oven for drying and calcined in a muffle furnace to obtain zirconium-doped boehmite.

[0069] At the same time, the mixed slurry is placed on a constant temperature magnetic stirrer, and the pH is adjusted to 8.8 by dilute nitric acid.

[0070] Further, in the zirconium-doped boehmite, the molar ratio of zirconium to aluminum is (Zr: Al) = 0-25%: 75%-100%.

[0071] Next, the zirconium-doped alumina carrier is prepared from the precursor boehmite using sodium aluminate as a precipitator and an aluminum source, one of aluminum nitrate, aluminum sulfate, and aluminum chloride as another aluminum source, and zirconium nitrate as a zirconium source.

[0072] Further, the carrier material is placed in deionized water (solid-liquid ratio = 1:50), ultrasonic dispersion is carried out for 2h, and it is added to the reaction kettle, high-speed stirring is carried out, and a constant temperature condition of 50°C is maintained.

[0073] At the same time, the concentration of the metal salt solution and the alkali solution is 1M, and they are added to the reaction kettle in a concurrent manner and the pH value in the reaction kettle is maintained at 8.

[0074] Finally, the copper-based catalyst is prepared by a step-by-step precipitation method, in which a large pore volume and high specific surface area zirconium-doped alumina carrier is prepared from boehmite, and then copper and zinc components are deposited on the carrier, and the metal molar ratio of the catalyst is (Cu:Zn:Al-Zr) = 50%-70%:20%-30%:5%-20%.

[0075] Example 2:

[0076] The preparation method of the copper-based catalyst for synthesizing methanol from CO2 provided by the application comprises the following steps:

[0077] Step 1: 2.4591 g (30 mmol) of NaAlO2 and x mmol of cetyltrimethylammonium bromide are weighed and placed in a beaker, and then 50 ml of deionized water is added and ultrasonically treated for 10 min until completely dissolved. (10-y) mmol of Al(NO3)3·9H2O and y mmol of Zr(NO3)4·5H2O are placed in another beaker, 50 ml of deionized water is added, and ultrasonically treated for 10 min until completely dissolved. The amount of the template cetyltrimethylammonium bromide added is in a molar ratio of (CTAB:Zr-Al) = (1:20-100) to zirconium and aluminum.

[0078] Step 2: A nucleation reactor is started, and the rotation speed is set to 3000 r / min. The prepared NaAlO2 solution and Al(NO3)3·9H2O solution are injected. After 5 min of grinding, the solution is poured into a beaker and placed on a constant-temperature magnetic stirrer, and the pH is adjusted to 8.8 by dilute nitric acid.

[0079] Step 3: The slurry in step 2 is stirred at room temperature for 2 h, and then the temperature is raised to 50℃ for aging treatment, which lasts for 2 h. After the aging process is completed, centrifugal separation is performed, and the product is washed with deionized water for 3 times. The product is placed in an oven at 65℃ for drying for 12 h, and after drying, it is ground into a fine powder using a agate mortar to obtain a boehmite product. In the zirconium-doped boehmite, the molar ratio of zirconium to aluminum is (Zr:Al) = 0-25%:75%-100%.

[0080] Step 4: After the zirconium-doped boehmite sample synthesized in step 2 is calcined at 550℃ in a muffle furnace in an air atmosphere for 2 hours, it is ground into a powder using a agate mortar to obtain a large pore volume and high specific surface area zirconium-doped alumina carrier, which is prepared from the precursor boehmite using sodium metaaluminate as a precipitator, one of aluminum nitrate, aluminum sulfate and aluminum chloride as another aluminum source, and zirconium nitrate as a zirconium source.

[0081] Step 5: The carrier material of step 4 is put into deionized water (solid-liquid ratio = 1:50) and ultrasonic dispersed for 2h, and then added into a reaction kettle, high-speed stirring, and keeping 50℃ constant temperature condition, configuring 1M copper zinc metal salt solution and sodium carbonate solution, and adding into the reaction kettle in a parallel flow mode and keeping the pH value in the reaction kettle as 8, and after dropwise adding, aging for 4h.

[0082] Step 6: The material obtained in step 5 is washed with deionized water, and the washing end point is that the pH value is 7 and there is no Na ion residue, and then placed in a 105℃ air drying oven for drying for 12h, and after drying, ground into powder by using a agate mortar.

[0083] Step 7: The material obtained in step 6 is placed in a muffle furnace and calcined at 350℃ for 4h, and after calcination, ground into fine powder by using a agate mortar to obtain a copper-based catalyst, wherein the copper-based catalyst is prepared by a step-by-step precipitation method, first preparing a zirconium-doped alumina carrier with large pore volume and high specific surface area by using boehmite, and then depositing copper zinc components on the carrier, and the metal molar ratio of the catalyst is (Cu:Zn:Al-Zr) = 50%~70%:20%~30%:5%~20%.

[0084] Step 8: The catalyst obtained in step 7 is pressed, granulated, and sieved, and 20-40 mesh samples are reserved.

[0085] Secondly, the copper-based catalyst of the present application is used for catalyzing the reaction of CO2 and hydrogen to synthesize methanol, and the catalyst has excellent activity and stability for the reaction of CO2 to synthesize methanol, thereby effectively realizing the conversion and utilization of CO2.

[0086] comprising the following steps:

[0087] The copper-based catalyst of the present application is used to prepare methanol by using CO2 and hydrogen as raw materials under the conditions of a reaction pressure of 3MPa and a reaction temperature of 220~280℃.

[0088] The activity evaluation of the catalyst in the reaction of CO2 hydrogenation to synthesize methanol is carried out on a fixed bed. The specific experimental process is as follows: a certain amount of catalyst is loaded into a stainless steel reaction tube. Pure hydrogen is introduced into the reaction tube at atmospheric pressure, and the space velocity is about 2000~3000h -1The reduction temperature was 300℃, the reduction time was 3h, the gas in the reaction tube was switched to nitrogen, and the temperature was reduced to the reaction starting temperature. Then the gas in the reaction tube was switched to the raw material gas (hydrogen to carbon ratio was 3, containing a certain amount of nitrogen as an internal standard), the pressure was increased to 3.0 MPa, and after the reaction reached a stable state, the composition of the raw material gas and the product was analyzed online by chromatography. The composition of the raw material gas and the product was analyzed online by Agilent 7890B chromatography, with two detectors of TCD and FID, two chromatographic columns of TDX-01 (2.0m x 2mm) and FFAP (30.0m x 0.32mm x 1.0μm), wherein the former column was used for detecting and analyzing CO and CO2, and the latter chromatographic column was used for detecting and analyzing CH4 and CH3OH.

[0089] Example 3:

[0090] Preparation of copper-based catalyst with large pore volume and high specific surface area zirconium-doped alumina as carrier prepared by step-by-step precipitation method

[0091] 2.4591g (30mmol) of NaAlO2 and 0.3645g (1mmol) of cetyltrimethylammonium bromide were weighed into a beaker, followed by the addition of 50ml of deionized water and ultrasonic treatment for 10min until complete dissolution. 4mmol of Al(NO3)3·9H2O and 6mmol of Zr(NO3)4·5H2O were taken into another beaker, 50ml of deionized water was added, and ultrasonic treatment was performed for 10min until complete dissolution. The nucleation reactor was started, the rotation speed was set to 3000r / min, and the prepared NaAlO2 solution and Al(NO3)3·9H2O solution were injected. After 5min of grinding, it was poured into a beaker and placed on a constant-temperature magnetic stirrer, and the pH was adjusted to 8.8 by dilute nitric acid. Stirring was carried out at room temperature for 2h, and then the temperature was raised to 50℃ for aging treatment, which lasted for 2h. After the aging process was completed, centrifugal separation was performed, and deionized water was used for washing 3 times. The product was placed in an oven at 65℃ for drying for 12h, and after drying, it was ground into a fine powder using a agate mortar, thereby obtaining the boehmite product.

[0092] The boehmite sample was calcined in a muffle furnace in an air atmosphere for 2 hours, and then ground into powder using an agate mortar to obtain a high pore volume and high specific surface area zirconium-doped alumina carrier. The carrier material was dispersed in deionized water (solid-liquid ratio = 1:50) for 2 hours, and then added to a reaction kettle, stirred at high speed, and kept at a constant temperature of 50°C. A 1M copper-zinc metal salt solution and a sodium carbonate solution were prepared and added to the reaction kettle in a concurrent manner while keeping the pH value in the reaction kettle at 8. After the dropwise addition was completed, the mixture was aged for 4 hours. After the reaction was completed, the product was washed with deionized water until the pH value was 7 and no Na ions were left, and then dried in a 105°C air-drying oven for 12 hours. After drying, the product was ground into powder using an agate mortar. The powder was calcined in a muffle furnace at 350°C for 4 hours, and then a copper-based catalyst (Cu:Zn:Zr-Al) = 6:3:1 was obtained.

[0093] Examples 4-8:

[0094] The method was the same as that in Example 3, and the process conditions were changed. In Examples 4-8, the molar ratio of the metals was (Cu:Zn:Zr-Al) = 6:3:1, and the molar ratio of zirconium nitrate and aluminum nitrate was changed to (Zr:Al) = 0:10, (Zr:Al) = 2:8, (Zr:Al) = 4:6, (Zr:Al) = 8:2, and (Zr:Al) = 10:0. 0 indicates that the material was not added.

[0095] Examples 9-12:

[0096] The method was the same as that in Example 3, and the process conditions were changed. In Examples 9-12, the molar ratio of zirconium nitrate and aluminum nitrate was fixed at (Zr:Al) = 6:4, and the molar ratio of Cu, Zn, and Zr-Al was changed to (Cu:Zn:Zr-Al) = 5:3:2, (Cu:Zn:Zr-Al) = 6.5:3:0.5, (Cu:Zn:Zr-Al) = 6.5:2.5:1, and (Cu:Zn:Zr-Al) = 7:2:1.

[0097] Examples 13-17:

[0098] The method was the same as that in Example 3, and the process conditions were changed. In Examples 13-17, the molar ratio of zirconium nitrate and aluminum nitrate was fixed at (Zr:Al) = 6:4, and the molar ratio of the template CTAB and zirconium and aluminum was changed to no CTAB, (CTAB:Zr-Al) = (1:100), (CTAB:Zr-Al) = (1:80), (CTAB:Zr-Al) = (1:60), and (CTAB:Zr-Al) = (1:20).

[0099] Example 18:

[0100] The conditions are the same as in Example 3, and after the catalyst has been operated for 5000 h, chromatographic sampling is performed for detection:

[0101] Comparative Example 1: In the comparative example, a copper-based catalyst is prepared by using a traditional one-step coprecipitation method. The preparation steps are as follows: 14.496 g (60 mmol) of copper nitrate, 8.925 g (30 mmol) of zinc nitrate and 3.751 g (10 mmol) of aluminum nitrate are weighed into a beaker, 100 ml of deionized water is added, and ultrasonic treatment is performed for 10 min until the solids are completely dissolved. 17.669 g (166 mmol) of sodium carbonate is weighed, dissolved in 100 ml of deionized water, and ultrasonic treatment is performed for 10 min until the solids are completely dissolved. An appropriate amount of water is added to a 500 ml beaker in advance, and the beaker is preheated to 50°C. The metal salt solution and the base solution are added to the beaker in a parallel flow manner, and the pH value of the solution is maintained at 8. After the addition is completed, aging is performed for 4 h. The slurry is centrifuged, and the product is washed with deionized water. The washing endpoint is that there is no Na ion residue, and the pH value of the washing liquid is 7. The product is placed in a 105°C air-drying oven for 12 h. After drying, the product is ground into a powder using a corundum mortar. The powder is placed in a muffle furnace and calcined at 350°C for 4 h. After calcination, a comparative copper-based catalyst is obtained, and the metal molar ratio is (Cu:Zn:Al) = 6:3:1.

[0102] Comparative Examples 2-6: The method is the same as in Comparative Example 1, and the process conditions for preparation are changed. In Comparative Examples 2-6, zirconium nitrate components are added, and the addition amounts are (Zr:Al) = 2:8, (Zr:Al) = 4:6, (Zr:Al) = 6:4, (Zr:Al) = 8:2, and (Zr:Al) = 10:0, respectively. 0 indicates that the material is not added. The total metal molar ratio is (Cu:Zn:Zr-Al) = 6:3:1.

[0103] Comparative Example 7: The conditions are the same as in Comparative Example 1, and after the catalyst has been operated for 5000 h, chromatographic sampling is performed for detection.

[0104] Table 1: CO2 hydrogenation to methanol catalysts prepared under different preparation process conditions

[0105]

[0106] Table 2: Comparative examples of CO2 hydrogenation to methanol catalysts prepared under different preparation process conditions

[0107]

[0108]

[0109] Although the present application has been described with reference to the embodiments above, various changes and modifications can be suggested to one skilled in the art, and it is intended that the present application encompass such changes and modifications as fall within the scope of the appended claims. Particularly, each feature disclosed in the description and / or the claims can be used in the combination with each of the features disclosed in the description and / or the claims, unless specifically stated otherwise. Therefore, the present application is not intended to be limited to the particular embodiments disclosed in the description and / or the claims.

Claims

1. A copper-based catalyst for the synthesis of methanol from CO2, characterized in that, It includes the following components: a) Sodium aluminate; b): Hexadecyltrimethylammonium bromide; c): Aluminum nitrate; d): Zirconium nitrate; e): Deionized water; f): Aluminum sulfate; g): Aluminum chloride; h): Copper nitrate; i): Zinc nitrate.

2. The copper-based catalyst for CO2 to methanol synthesis according to claim 1, characterized in that, The molar ratio of the cetyltrimethylammonium bromide added to zirconium and aluminum, in proportions, is: (CTAB:Zr-Al)=(1:20~100).

3. The method for preparing the copper-based catalyst for CO2 to methanol according to claim 2, characterized in that, Sodium aluminate (NaAlO2) and hexadecyltrimethylammonium bromide (CTAB) were dissolved in deionized water, as were aluminum nitrate (Al(NO3)3·9H2O) and zirconium nitrate (Zr(NO3)4·5H2O). The nucleation reactor was turned on, and the prepared solutions were injected. The slurry was then removed, placed on a constant-temperature magnetic stirrer, and the pH was adjusted. After aging, the product was centrifuged, washed, dried in an oven, and calcined in a muffle furnace to obtain zircon-doped boehmite.

4. The method for preparing the copper-based catalyst for CO2 to methanol according to claim 3, characterized in that, The slurry is placed on a constant-temperature magnetic stirrer and the pH is adjusted to 8.8 using dilute nitric acid.

5. The method for preparing the copper-based catalyst for CO2 to methanol according to claim 4, characterized in that, In the zircon-doped boehmite, the molar ratio of zirconium to aluminum is (Zr:Al) = 0–25% : 75%–100%.

6. The method for preparing the copper-based catalyst for CO2 to methanol according to claim 5, characterized in that, The zirconium-doped alumina carrier is prepared from boehmite precursor, using sodium aluminate as the precipitant and aluminum source, aluminum nitrate, aluminum sulfate, or aluminum chloride as the other aluminum source, and zirconium nitrate as the zirconium source.

7. The method for preparing the copper-based catalyst for CO2 to methanol according to claim 6, characterized in that, The carrier material is placed in deionized water (solid-liquid ratio = 1:50), ultrasonically dispersed for 2-3 hours, added to the reaction vessel, stirred at high speed, and kept at a constant temperature of 50℃-65℃.

8. The method for preparing the copper-based catalyst for CO2 to methanol according to claim 7, characterized in that, The metal salt solution and the alkaline solution are prepared with a concentration of 1M and are added to the reactor in a parallel flow manner while maintaining the pH value of the reactor at 8.

9. The method for preparing the copper-based catalyst for CO2 to methanol according to claim 8, characterized in that, The copper-based catalyst is prepared by a stepwise precipitation method. First, a zirconium-doped alumina support with large pore volume and high specific surface area is prepared by boehmite. Then, the copper and zinc components are deposited on the support. The metal molar ratio of the catalyst is (Cu:Zn:Al-Zr) = 50%~70%:20%~30%:5%~20%.

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