CuO-ZnO supported membrane reactor for the production of methanol by CO2 hydrogenation

Abstract

The application discloses a CuO-ZnO supported membrane catalytic reactor for preparing methanol by CO2 hydrogenation. Specifically, the application provides a CuO-ZnO@Cu-MOR membrane catalytic reactor for preparing methanol by catalyzing CO2 hydrogenation; wherein, the CuO-ZnO is a catalytic layer, the Cu-MOR membrane is a separation layer, and the CuO-ZnO is attached to the surface of the Cu-MOR in a coating mode; the thickness of the catalytic layer is 1-40 microns; the silicon-aluminum ratio of the Cu-MOR membrane is 5-20; and the copper content of the Cu-MOR membrane is 0.5-3 wt%.

Description

Technical Field

[0001] This invention belongs to the field of catalysis technology, and particularly relates to a membrane catalytic reactor for the hydrogenation of CO2 to methanol, its preparation method and application. Background Technology

[0002] Catalytic membrane reactors (CMRs) combine catalytic reactions and separation processes within a single unit. The hydrophilic separation membrane effectively removes water, a byproduct, minimizing the impact of water deactivation. Based on Le Chatelier's principle, this effectively overcomes thermodynamic equilibrium limitations, significantly improving reaction conversion and product selectivity, and extending catalyst lifetime. Furthermore, CMRs enhance reactant diffusion within the catalytic region, accelerating the reaction rate.

[0003] Mordenite (MOR) is a microporous aluminosilicate zeolite containing 12-membered ring (MR) straight channels (0.67 nm * 0.70 nm) and 8-MR straight channels (0.26 nm * 0.57 nm) along the c-axis, and tortuous 8-membered ring side rings (0.34 nm * 0.48 nm) along the b-axis. Due to its good hydrophilicity and structural stability resulting from a relatively high Si / Al ratio (5–20), it is considered a promising solvent dehydration material. Chuan Chen et al. (10.1016 / j.micromeso.2018.09.010) successfully prepared mordenite zeolite membranes on four-channel ceramic hollow fiber substrates using a two-stage hydrothermal synthesis method. Using submicron-sized MOR particles obtained by ball milling as seed crystals, they induced the formation of a high Si / Al and defect-free MOR membrane, achieving a high selectivity of over 10,000 for IPA / H2O (90 / 10wt%) mixtures and a permeation flux of 1.43 kg m⁻²h⁻¹.

[0004] Furthermore, the unique topology of MOR zeolites ensures excellent catalytic performance in reactions such as alkylation, hydroisomerization, cracking, and carbonylation. Sushkevich et al. (10.1126 / science.aam9035) used Cu-modified Cu-MOR for methane oxidation, achieving a high selectivity (~97%) for the conversion of methane to methanol. In our previous study (10.1002 / cctc.202300662), we developed a novel CAZA / Cu-MOR tandem catalyst for the high selectivity conversion of CO2 to methanol. During the hydrogenation of CO2 to methanol using the CZA / Cu catalyst, the byproducts methane and water were simultaneously and continuously converted to methanol via Cu-MOR, significantly increasing the CO2 conversion rate from 28.9% to 40.7% and the methanol selectivity from 84.9% to 97.6%. The high Si / Al ratio, good hydrophilicity, and unique catalytic performance make MOR a promising candidate for applications in membrane catalytic reactors.

[0005] It is worth noting that the existing membrane catalytic reactors have a silicon-to-aluminum ratio of only about 5, which is unstable in high-temperature, high-pressure, and long-term reactions, thus limiting the further development and industrial application value of this research field.

[0006] Therefore, there is an urgent need in this field to develop stable and high-performance membrane catalytic reactors for the catalytic hydrogenation of carbon dioxide to methanol. Summary of the Invention

[0007] One object of the present invention is to provide a CuO-ZnO@Cu-MOR membrane catalytic reactor with stable catalytic performance and high catalytic efficiency.

[0008] Another object of the present invention is to provide a method for preparing a CuO-ZnO@Cu-MOR membrane catalytic reactor.

[0009] In a first aspect of the present invention, a membrane catalytic reactor for the catalytic hydrogenation of CO2 to methanol is provided, wherein the membrane catalytic reactor is a CuO-ZnO@Cu-MOR membrane catalytic reactor;

[0010] In this structure, CuO-ZnO serves as the catalyst layer, and the Cu-MOR membrane serves as the separation layer. CuO-ZnO is coated onto the surface of the Cu-MOR membrane. The thickness of the catalyst layer ranges from 1 to 40 μm. The silicon-to-aluminum ratio of the Cu-MOR membrane ranges from 5 to 25. The copper content of the Cu-MOR membrane ranges from 0.5 to 3 wt%.

[0011] In another preferred embodiment, the silicon-to-aluminum ratio of the Cu-MOR film is 5-20; more preferably 10-20.

[0012] In another preferred embodiment, the CuO-ZnO@Cu-MOR membrane catalytic reactor is prepared by the method described in the second aspect of the present invention.

[0013] In another preferred embodiment, the CuO-ZnO@Cu-MOR membrane catalytic reactor exhibits a selectivity of 90–98% for methanol and a carbon dioxide conversion rate of 22–36%.

[0014] In another preferred embodiment, the CuO-ZnO@Cu-MOR membrane catalytic reactor has a service life of up to 200 hours.

[0015] In a second aspect of the present invention, a method for preparing a CuO-ZnO@Cu-MOR membrane catalytic reactor is provided, comprising the following steps:

[0016] Step 1: Grind copper salt, zinc salt and polyvinylpyrrolidone (PVP) together for at least 20 minutes to obtain CuO-ZnO precursor;

[0017] Step 2: The porous support layer is surface modified with a toluene solution of 3-aminopropyltriethoxysilane (APTES) at a concentration of 1-5 wt%; the modified porous support layer is immersed in a synthesis solution with a molar composition of 16Na2O:20-100SiO2:2Al2O3:500H2O and reacted at 170-180℃ for 36-96 hours to obtain a Na-MOR film;

[0018] Step 3: Immerse the Na-MOR membrane obtained in Step 2 in a copper ion solution for ion exchange, and dry it at 100-120℃ to obtain a Cu-MOR membrane;

[0019] Step 4: Coat the CuO-ZnO precursor obtained in Step 1 onto the Cu-MOR membrane obtained in Step 3, dry it at 60-120℃, and then calcine it at high temperature to obtain the CuO-ZnO@Cu-MOR membrane catalytic reactor.

[0020] In another preferred embodiment, the porous support layer has a porosity of 10 to 30%.

[0021] In another preferred embodiment, the porous support layer is an alumina tube.

[0022] In another preferred embodiment, the alumina tube is an α-Al2O3 tube.

[0023] In another preferred embodiment, the modified alumina tube is sealed with a polytetrafluoroethylene (PTFE) plug.

[0024] In another preferred embodiment, in step 3, the copper ion solution can also be a solution of other metal ions, such as an iron ion solution.

[0025] In another preferred embodiment, in step 1, the molar ratio of Cu to Zn in the copper salt and zinc salt is 2:1; and / or the mass ratio of copper salt to PVP is 100 to 50:1.

[0026] In another preferred embodiment, in step 1, the mass percentage of PVP in the CuO-ZnO precursor is 0.5 to 5 wt%.

[0027] In another preferred embodiment, in step 2, the silicon-to-aluminum ratio in the Na-MOR film is 5-25; more preferably 5-20; and even more preferably 10-20.

[0028] In another preferred embodiment, the Cu content in the Cu-MOR film obtained in step 3 is 0.5–3 wt%.

[0029] In another preferred embodiment, the copper salt is selected from the group consisting of copper nitrate, copper chloride, copper sulfate, basic copper carbonate, or combinations thereof.

[0030] In another preferred embodiment, the zinc salt is selected from the group consisting of zinc chloride, zinc sulfate, zinc nitrate, zinc acetate, or combinations thereof.

[0031] In another preferred embodiment, the molecular weight of the polyvinylpyrrolidone is 3000 to 10000.

[0032] In another preferred embodiment, the grinding time is 20–60 min; more preferably 20–30 min.

[0033] In another preferred embodiment, the grinding is carried out at room temperature, preferably 5-30°C.

[0034] In another preferred embodiment, the grinding is clockwise.

[0035] In another preferred embodiment, the grinding is carried out in a mortar, preferably an agate mortar.

[0036] In another preferred embodiment, step 1 specifically includes the following steps: at room temperature, copper salt and zinc salt are placed in a mortar and ground until they become gel-like (liquid), and then polyvinylpyrrolidone (PVP) is added and ground together for 20-60 minutes to obtain CuO-ZnO precursor.

[0037] In another preferred embodiment, the sodium salt is sodium hydroxide.

[0038] In another preferred embodiment, the silicon (Si) salt is sodium silicate (Na2SiO3), silica sol (SiO2), silicon dioxide (SiO2), or a combination thereof.

[0039] In another preferred embodiment, the aluminum (Al) salt is sodium aluminate (NaAlO2), aluminum chloride (AlCl3), or a combination thereof.

[0040] In another preferred embodiment, in step 2, the modification temperature is 100-120°C, more preferably 105-115°C.

[0041] In another preferred embodiment, step 2 specifically includes the following steps: at 100-120°C, the surface of the α-Al2O3 tube is modified for 2 hours using a toluene solution of 3-aminopropyltriethoxysilane (APTES) with a concentration of 1-5 wt%. The modified α-Al2O3 tube is then sealed at both ends and immersed in a synthetic solution with a molar composition of 16Na2O:20-100SiO2:2Al2O3:500H2O. The reaction is carried out at 170-180°C for 36-96 hours to obtain a Na-MOR film.

[0042] In another preferred embodiment, step 2 further includes washing and drying the resulting Na-MOR membrane.

[0043] In another preferred embodiment, in step 3, the concentration of copper ions in the copper ion solution is 0.01-0.1 mol / L; more preferably 0.04-0.07 mol / L; and most preferably 0.05 mol / L.

[0044] In another preferred embodiment, in step 3, the copper ion solution is a copper nitrate solution, a copper chloride solution, a copper sulfate solution, a basic copper carbonate solution, or a combination thereof.

[0045] In another preferred embodiment, the ion exchange time in step 3 is 2 to 10 hours.

[0046] In another preferred embodiment, in step 3, the temperature of ion exchange is 40-60°C; more preferably 50°C.

[0047] In another preferred embodiment, step 3 specifically includes the following steps: immersing the Na-MOR membrane obtained in step 2 in a copper ion solution with a concentration of 0.01-0.1 mol / L, stirring at 40-60°C for ion exchange for 2-10 hours, and then drying at 100-130°C for 1-4 hours to obtain a Cu-MOR membrane.

[0048] In another preferred embodiment, in step 4, the CuO-ZnO precursor is uniformly coated onto the Cu-MOR film using a brush.

[0049] In another preferred embodiment, in step 4, the drying is carried out in a blower oven.

[0050] In another preferred embodiment, in step 4, the drying time is 6-24 hours; more preferably 10-14 hours.

[0051] In another preferred embodiment, in step 4, the dried Cu-MOR film is placed in an alumina ceramic boat and then placed in a muffle furnace for calcination.

[0052] In another preferred embodiment, in step 4, the muffle furnace is heated at 3°C / min, maintained at 400–600°C for 2–8 hours, and then cooled naturally.

[0053] In another preferred embodiment, step 4 specifically includes the following steps: coating the CuO-ZnO precursor obtained in step 1 onto the Cu-MOR membrane obtained in step 3, drying it at 60-120°C for 6-24 hours, calcining it in a muffle furnace for 2-8 hours, and then cooling it to obtain the CuO-ZnO@Cu-MOR membrane catalytic reactor.

[0054] In a third aspect of the invention, the use of a CuO-ZnO@Cu-MOR membrane catalytic reactor is provided for catalytic hydrogenation of carbon dioxide to methanol.

[0055] In another preferred embodiment, the conditions are: 200–300°C, 3.0–4.0 MPa pressure, H / C ratio of 4 / 1, and 5000 h. -1 At a given space velocity, the selectivity of the CuO-ZnO@Cu-MOR membrane catalytic reactor for methanol is 90–98%, and the carbon dioxide conversion rate is 22–36%.

[0056] In a fourth aspect of the invention, an apparatus for the catalytic hydrogenation of carbon dioxide to methanol is provided, wherein the apparatus is equipped with the membrane catalytic reactor of claim 1.

[0057] In another preferred embodiment, the parameters of the device are configured as follows: 200–300°C, 3.0–4.0 MPa pressure, H / C ratio of 4 / 1, and space velocity of 4000–8000 h⁻¹. -1 .

[0058] In another preferred embodiment, the airspeed is 4000-6000 h. -1 .

[0059] It should be understood that, within the scope of this invention, the above-described technical features of this invention and the technical features specifically described below (such as in the embodiments) can be combined with each other to form new or preferred technical solutions. Due to space limitations, they will not be described in detail here. Attached Figure Description

[0060] Figure 1 These are the XRD patterns of Na-MOR membrane, Cu-MOR membrane, and CuO-ZnO@Cu-MOR membrane catalytic reactors;

[0061] Figure 2 The images show the SEM surface (a) and cross-sectional (e) images of the CuO-ZnO@Cu-MOR membrane catalytic reactor, and the EDS spectra of the surface (bd) and cross-sectional (fj) images.

[0062] Figure 3 This is a test of the catalytic performance of the CuO-ZnO@Cu-MOR membrane catalytic reactor for long-term CO2 hydrogenation over 200 hours. Detailed Implementation

[0063] Through extensive and in-depth research, the inventors have developed for the first time a CuO-ZnO@Cu-MOR membrane catalytic reactor and its preparation method. Specifically, the CuO-ZnO@Cu-MOR membrane catalytic reactor is obtained by loading copper oxide (CuO) and zinc oxide (ZnO) onto a hydrophilic Cu-MOR zeolite membrane. This reactor can not only effectively remove water vapor as a byproduct in situ, but also promote the further conversion of methane and water into methanol. Furthermore, by introducing PVP into the CuO-ZnO catalyst layer precursor, the adhesion and dispersibility of the catalyst layer on the Cu-MOR membrane are enhanced. The CuO-ZnO@Cu-MOR membrane catalytic reactor of this invention achieves a CO2 conversion rate of 35.2% and a methanol selectivity of 96.7%, and maintains stable catalytic performance for up to 200 hours. Based on this, the inventors completed this invention.

[0064] Membrane catalytic reactor and its preparation method

[0065] This invention provides a membrane catalytic reactor that can operate stably for a long time and has high performance, aiming to reduce energy consumption, be environmentally friendly, and overcome thermodynamic limitations to obtain better performance.

[0066] Specifically, the present invention provides a CuO-ZnO@Cu-MOR membrane catalytic reactor for the hydrogenation of CO2 to methanol. The catalyst layer is prepared in one step by a solid-phase grinding process using CuO-ZnO with a certain molar ratio and different contents of PVP. The Cu-MOR membrane is obtained by ion exchange using Na-MOR membranes with different Si / Al ratios. The membrane reactor is formed by brushing the catalyst layer onto the Cu-MOR membrane and calcining it.

[0067] The thickness of the CuO-ZnO catalyst layer is 1–40 μm; the silicon-to-aluminum ratio of the Na-MOR film is 5–25; and the copper content of the Cu-MOR film is 0.5–3 wt%.

[0068] Compared to traditional deposition methods, coating allows the CuO-ZnO precursor catalyst to bond better to the Cu-MOR film surface.

[0069] Specifically, the preparation method of the membrane catalytic reactor includes the following steps:

[0070] Step 1: Weigh out a certain amount of copper salt, zinc salt, and PVP, and place them in an agate mortar. Grind them clockwise for 20-30 minutes at room temperature to obtain the CuO-ZnO precursor. The copper salt is copper nitrate, copper chloride, copper sulfate, and basic copper carbonate; the zinc salt is zinc chloride, zinc sulfate, zinc nitrate, and zinc acetate; and the PVP has a molecular weight of 3000-10000.

[0071] Step 2: The α-Al₂O₃ tube was surface-modified using a 1-5 wt% solution of 3-aminopropyltriethoxysilane (APTES) in toluene at 110°C for 2 hours. The modified α-Al₂O₃ tube was then sealed at both ends with polytetrafluoroethylene (PTFE) plugs and immersed in a synthetic solution with a molar composition of 16Na₂O:20-100SiO₂:2Al₂O₃:500H₂O. Hydrothermal synthesis was carried out at 170-180°C for 36-96 hours. After washing and drying, a Na-MOR film was obtained. The sodium (Na) salt was sodium hydroxide; the silicon (Si) salt was sodium silicate (Na₂SiO₃), silica sol (SiO₂), or silicon dioxide (SiO₂); and the aluminum (Al) salt was sodium aluminate (NaAlO₂) or aluminum chloride (AlCl₃).

[0072] Step 3: Immerse the Na-MOR membrane obtained in Step 2 in a 0.05 mol / L copper ion solution, stir at 50°C for 2-10 hours for ion exchange, and then dry at 110-120°C for 2 hours to obtain a Cu-MOR membrane; wherein the copper salt is copper nitrate, copper chloride, copper sulfate and basic copper carbonate.

[0073] Step 4: The CuO-ZnO precursor obtained in Step 1 is evenly brushed onto the Cu-MOR membrane obtained in Step 3. It is first dried overnight in a forced-air oven at 60–120°C, then placed in an alumina ceramic boat and calcined in a muffle furnace. After cooling to room temperature, the CuO-ZnO@Cu-MOR membrane catalytic reactor is obtained. The muffle furnace heating program is 3°C / min, maintained at 400–600°C for 2–8 hours, followed by natural cooling.

[0074] In the method of this invention, in step 1, copper salt and zinc salt need to be ground into a gel-like liquid before slowly adding PVP. The order cannot be changed. If it is changed, it will solidify and cannot form a uniform gel. After calcination in a muffle furnace, it will form a blocky solid and cannot form a uniform powdered catalyst, making it unusable (catalytic performance cannot be tested). It is important to note that the order of addition and the grinding time should be at least 20 minutes.

[0075] In one specific implementation, the α-Al2O3 tube in step 2 is used as a porous support layer to provide support for the attachment of the CuO-ZnO precursor.

[0076] In one specific implementation, the copper ion solution in step 3 can also be a solution of other metal ions, such as iron ions.

[0077] In one specific embodiment, the calcination in the muffle furnace causes the CuO-ZnO precursor to solidify on the surface of the support layer, while simultaneously oxidizing the metal elements.

[0078] Preferably, the molecular weight of PVP is 3000 to 10000.

[0079] Preferably, the PVP content in CuO-ZnO is 0.5–5 wt%.

[0080] Preferably, the silicon-to-aluminum ratio of the Na-MOR film is 5 to 20.

[0081] Preferably, the Cu content of the Cu-MOR film is 0.5–3 wt%.

[0082] The CuO-ZnO@Cu-MOR membrane catalytic reactor achieved CO2 hydrogenation to methanol using a membrane catalytic testing device. The test was conducted at a temperature of 200–300 °C, a pressure of 3.0–4.0 MPa, an H / C ratio of 4 / 1, and a test duration of 5000 h⁻¹. -1 At the given space velocity, the selectivity for methanol is 90–98%, and the carbon dioxide conversion rate is 22–36%.

[0083] One application of the above-mentioned CuO-ZnO@Cu-MOR membrane catalytic reactor is for the catalytic hydrogenation of carbon dioxide to produce methanol.

[0084] In one embodiment, the conditions are: 200–300°C, 3.0–4.0 MPa pressure, H / C ratio of 4 / 1, and 5000 h. -1 At a given space velocity, the selectivity of the CuO-ZnO@Cu-MOR membrane catalytic reactor for methanol is 90–98%, and the carbon dioxide conversion rate is 22–36%.

[0085] Furthermore, the present invention also provides an apparatus using the above-described membrane catalytic reactor, wherein the membrane catalytic reactor is configured in the apparatus.

[0086] In one embodiment, the parameters of the device are configured as follows: 200–300°C, 3.0–4.0 MPa pressure, H / C ratio of 4 / 1, and space velocity of 4000–8000 h⁻¹. -1 Ideally, the airspeed should be 4000-6000 h / h. -1 The selectivity for methanol is 90–98%, and the carbon dioxide conversion rate is 22–36%.

[0087] Compared with the prior art, the main advantages of the present invention include:

[0088] (1) The preparation method of this invention is rapid and simple. A CuO-ZnO catalyst precursor is obtained by adding PVP. Then, the separation membrane is modified with Cu to obtain a Cu-MOR membrane. After brushing the catalyst layer and calcining, it is used for CO2 hydrogenation to methanol, which can significantly improve the C O2 The conversion efficiency is high, and the selectivity of methanol can reach over 98%.

[0089] (2) The CuO-ZnO@Cu-MOR membrane catalytic reactor of the present invention has good stability after long-term testing, indicating that the membrane reactor prepared by the present invention has a long life, good stability, and is not easily deactivated, thus providing a new idea for the preparation of membrane reactors for CO2 hydrogenation to methanol.

[0090] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. Percentages and parts are by weight unless otherwise stated.

[0091] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as are familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to the methods of this invention. The preferred embodiments and materials described herein are for illustrative purposes only.

[0092] Example 1

[0093] The CuO-ZnO@Cu-MOR membrane catalytic reactor is synthesized as follows:

[0094] Step 1: Weigh 2.5g of copper nitrate trihydrate, 3.1g of zinc nitrate hexahydrate and 0.03g of PVP (molecular weight 6000) and put them into an agate mortar. Grind clockwise for 20 minutes at room temperature to obtain a precursor with a PVP content of 0.5wt%.

[0095] Step 2: The α-Al₂O₃ tube was surface-modified using a 1.5 wt% solution of 3-aminopropyltriethoxysilane (APTES) in toluene at 110°C for 2 hours. The modified α-Al₂O₃ tube was then sealed at both ends with polytetrafluoroethylene (PTFE) plugs and immersed in a synthetic solution with a molar composition of 16Na₂O:20SiO₂:2Al₂O₃:500H₂O. Hydrothermal synthesis was performed at 170–180°C for 36–96 hours. After washing and drying, the Na-MOR-5 film was obtained.

[0096] Step 3: Immerse the Na-MOR-5 membrane obtained in Step 2 in a 0.05 mol / L copper ion solution, stir at 50°C for 2-10 hours for ion exchange, and then dry at 110°C for 2 hours to obtain a Cu-MOR-5 membrane.

[0097] Step 4: The CuO-ZnO precursor obtained in Step 1 is evenly brushed onto the Cu-MOR-5 membrane obtained in Step 3. It is first dried overnight in a forced-air oven at 60–120°C, then placed in an alumina ceramic boat and calcined in a muffle furnace. After cooling to room temperature, the CuO-ZnO@Cu-MOR-5 membrane catalytic reactor is obtained. The muffle furnace heating program is 3°C / min, maintained at 400–600°C for 2–8 hours, followed by natural cooling.

[0098] Step 5: Catalyst Activity Evaluation Results: The CuO-ZnO@Cu-MOR-5 membrane catalytic reactor from Step 4 was used in a micro membrane catalytic reactor for CO2 hydrogenation to methanol. First, reduction was carried out at a constant temperature of 250℃ for 3 hours under an H2 / CO2 atmosphere of 4 / 1, with a heating rate of 3℃ / min; the space velocity (GHSV) was 5000 h⁻¹. -1 The evaluation temperature was 250℃, the evaluation pressure was 3.0MPa, and the evaluation time was 30h. Finally, the tail gas and liquid products were detected and analyzed by Agilent Technologies 7890B gas chromatography (GC). The formulas for calculating the CO2 conversion rate and the selectivity of the CH3OH product are as follows. The catalytic results are shown in Table 1.

[0099]

[0100] Example 2

[0101] The CuO-ZnO@Cu-MOR membrane catalytic reactor is synthesized as follows:

[0102] Step 1: Weigh 2.5g of copper nitrate trihydrate, 3.1g of zinc nitrate hexahydrate and 0.06g of PVP (molecular weight 6000) and put them into an agate mortar. Grind clockwise for 20 minutes at room temperature to obtain a precursor with a PVP content of 1.0wt%.

[0103] Step 2: Using the same synthesis solution as in Example 1 (16Na2O:40SiO2:2Al2O3:500H2O), a Na-MOR-10 membrane was obtained.

[0104] Step 3: Same as step 3 in Example 1 to obtain the Cu-MOR-10 film.

[0105] Step 4: Same as step 4 in Example 1 to obtain the CuO-ZnO@Cu-MOR-10 membrane catalytic reactor.

[0106] Step 5: Catalyst activity evaluation is the same as step 5 in Example 1. The results are shown in Table 1.

[0107] Example 3

[0108] The CuO-ZnO@Cu-MOR membrane catalytic reactor is synthesized as follows:

[0109] Step 1: Weigh 2.5g of copper nitrate trihydrate, 3.1g of zinc nitrate hexahydrate and 0.12g of PVP (molecular weight 6000) and put them into an agate mortar. Grind clockwise for 20 minutes at room temperature to obtain a precursor with a PVP content of 2.0wt%.

[0110] Step 2: Using the same synthesis solution as in Step 2 of Example 1, 16Na2O:80SiO2:2Al2O3:500H2O is used to obtain the Na-MOR-20 membrane.

[0111] Step 3: Same as step 3 in Example 1 to obtain the Cu-MOR-20 film.

[0112] Step 4: Same as Step 4 in Example 1 to obtain the CuO-ZnO@Cu-MOR-20 membrane catalytic reactor.

[0113] Step 5: Catalyst activity evaluation is the same as step 5 in Example 1. The results are shown in Table 1.

[0114] Example 4

[0115] The CuO-ZnO@Cu-MOR membrane catalytic reactor is synthesized as follows:

[0116] Step 1: Weigh 2.5g of copper nitrate trihydrate, 3.1g of zinc nitrate hexahydrate and 0.24g of PVP (molecular weight 6000) and put them into an agate mortar. Grind clockwise for 20 minutes at room temperature to obtain a precursor with a PVP content of 4.0wt%.

[0117] Step 2: Using the same synthesis solution of 16Na2O:100SiO2:2Al2O3:500H2O as in Step 2 of Example 1, a Na-MOR-25 membrane was obtained.

[0118] Step 3: Same as step 3 in Example 1 to obtain Cu-MOR-25 film.

[0119] Step 4: Same as step 4 in Example 1 to obtain the CuO-ZnO@Cu-MOR-25 membrane catalytic reactor.

[0120] Step 5: Catalyst activity evaluation is the same as step 5 in Example 1. The results are shown in Table 1.

[0121] Table 1. Catalytic performance of the CuO-ZnO@Cu-MOR membrane catalytic reactor synthesized in the above examples.

[0122]

[0123]

[0124] Test Example 1

[0125] Characterization of the CuO-ZnO@Cu-MOR membrane catalytic reactor:

[0126] The microstructure of the CuO-ZnO@Cu-MOR membrane catalytic reactor was analyzed by XRD (Bruker D8 ADVANCE). The test conditions were: Cu target, Kα radiation, Ni filter, tube voltage 40 kV, tube current 30 mA, scan range 5°-80° (2θ), scan rate 4° / min, step size 0.02°. The micromorphology of the CuO-ZnO@Cu-MOR membrane catalytic reactor was characterized by FESEM (S-4800) and EDS energy dispersive spectroscopy. All samples were sputter-coated with gold before testing.

[0127] Figure 1 The XRD patterns of the Na-MOR membrane obtained in step 2, the Cu-MOR membrane obtained in step 3, and the CuO-ZnO@Cu-MOR membrane catalytic reactor obtained in step 4 of the present invention are shown.

[0128] Figure 2 The image shows a scanning electron microscope (SEM) image and energy dispersive spectroscopy (EDS) plot of the CuO-ZnO@Cu-MOR membrane catalytic reactor of the present invention.

[0129] Test Example 2

[0130] Catalytic lifetime and catalytic performance testing of CuO-ZnO@Cu-MOR membrane catalytic reactor

[0131] like Figure 3 As shown, under the catalyst evaluation method in step 5, the CuO-ZnO@Cu-MOR membrane catalytic reactor of the present invention achieved a CO2 conversion rate of 35.2% and a methanol selectivity of 98%, and achieved long-term stable catalytic performance for up to 200 hours.

[0132] The preparation method of this invention is simple. A CuO-ZnO@Cu-MOR membrane catalytic reactor can be rapidly prepared by brush coating and used for CO2 hydrogenation to methanol. It can significantly improve the CO2 conversion efficiency and the methanol selectivity can reach 98%.

[0133] All documents mentioned in this invention are incorporated herein by reference as if each document were individually incorporated by reference. Furthermore, it should be understood that after reading the foregoing teachings of this invention, those skilled in the art can make various alterations or modifications to this invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A membrane catalytic reactor for the catalytic hydrogenation of CO2 to methanol, characterized in that, The membrane catalytic reactor is a CuO-ZnO@Cu-MOR membrane catalytic reactor; In this structure, CuO-ZnO serves as the catalyst layer, and the Cu-MOR membrane serves as the separation layer. CuO-ZnO is coated onto the surface of the Cu-MOR membrane. The thickness of the catalyst layer ranges from 1 to 40 μm. The silicon-to-aluminum ratio of the Cu-MOR membrane ranges from 5 to 25. The copper content of the Cu-MOR membrane ranges from 0.5 to 3 wt%.

2. A method for preparing a CuO-ZnO@Cu-MOR membrane catalytic reactor, characterized in that, Includes the following steps: Step 1: Grind copper salt, zinc salt and polyvinylpyrrolidone (PVP) together for at least 20 minutes to obtain CuO-ZnO precursor; Step 2: The porous support layer is surface modified with a toluene solution of 3-aminopropyltriethoxysilane (APTES) at a concentration of 1-5 wt%; the modified porous support layer is immersed in a synthesis solution with a molar composition of 16Na2O:20-100SiO2:2Al2O3:500H2O and reacted at 170-180℃ for 36-96 hours to obtain a Na-MOR film; Step 3: Immerse the Na-MOR membrane obtained in Step 2 in a copper ion solution for ion exchange, and dry it at 100-120℃ to obtain a Cu-MOR membrane; Step 4: Coat the CuO-ZnO precursor obtained in Step 1 onto the Cu-MOR membrane obtained in Step 3, dry it at 60-120℃, and then calcine it at high temperature to obtain the CuO-ZnO@Cu-MOR membrane catalytic reactor.

3. The preparation method according to claim 2, characterized in that, In step 1, the molar ratio of Cu to Zn in the copper salt and zinc salt is 2:1; and / or the mass ratio of copper salt to PVP is 100 to 50:

1.

4. The preparation method according to claim 2, characterized in that, In step 1, the mass percentage of PVP in the CuO-ZnO precursor is 0.5–5 wt%.

5. The preparation method according to claim 2, characterized in that, In step 2, the silicon-to-aluminum ratio in the Na-MOR film is 5-25; preferably 5-20; more preferably 10-20.

6. The preparation method according to claim 2, characterized in that, The Cu content in the Cu-MOR film obtained in step 3 is 0.5–3 wt%.

7. The preparation method according to claim 2, characterized in that, The copper salt is selected from the group consisting of copper nitrate, copper chloride, copper sulfate, basic copper carbonate, or combinations thereof; The zinc salt is selected from the group consisting of zinc chloride, zinc sulfate, zinc nitrate, zinc acetate, or combinations thereof; and / or the molecular weight of the polyvinylpyrrolidone is 3000 to 10000.

8. The preparation method according to claim 2, characterized in that, In step 3, the concentration of copper ions in the copper ion solution is 0.01-0.1 mol / L; preferably 0.04-0.07 mol / L; and most preferably 0.05 mol / L.

9. The application of a CuO-ZnO@Cu-MOR membrane catalytic reactor, characterized in that, Used for catalytic hydrogenation of carbon dioxide to produce methanol.

10. An apparatus for the catalytic hydrogenation of carbon dioxide to produce methanol, characterized in that, The device is equipped with the membrane catalytic reactor as described in claim 1.

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