Preparation method of catalyst for preparing methanol through carbon dioxide hydrogenation and catalyst
By using a catalyst prepared by thermal synthesis of copper foam support and nitric acid brine, the problems of insufficient activity and stability of carbon dioxide hydrogenation to methanol catalysts were solved, and the efficient conversion of carbon dioxide to methanol was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-12
- Publication Date
- 2026-04-17
AI Technical Summary
Existing catalysts for the hydrogenation of carbon dioxide to methanol have low catalytic activity and poor stability, resulting in low reaction conversion and selectivity.
A copper foam support was used as the catalyst support, and nitric acid-based copper salts and nitric acid-based zinc salts were used as metal precursors. The catalyst was prepared by hydrothermal synthesis. The copper foam support provides a large specific surface area and uniformly dispersed active sites, which combine with copper and zinc active components to form a stable copper-zinc composite phase.
It significantly improved the reaction efficiency and stability of carbon dioxide hydrogenation to methanol, and enhanced the yield and selectivity of the catalyst.
Smart Images
Figure CN121869370A_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of catalyst preparation technology, specifically relating to a method for preparing a catalyst for the hydrogenation of carbon dioxide to methanol and an electronic device. Background Technology
[0002] CO2 is one of the major greenhouse gases, and the increase in atmospheric CO2 levels has caused numerous environmental problems, including global warming, sea-level rise, ocean acidification, ecosystem destruction, frequent wildfires, floods, and intensified tropical storms. Therefore, how to effectively utilize CO2 and convert it into high-value-added chemicals has become a current research hotspot. Using abundant and inexpensive CO2 as a basic raw material, converting it into other high-value-added chemicals such as methane, methanol, and formates through chemical methods can not only effectively reduce atmospheric CO2 concentrations and alleviate environmental pressure, but also achieve the recycling of carbon resources. Methanol is an important basic chemical raw material, widely used in the synthesis of chemicals such as formaldehyde, acetic acid, and methyl tert-butyl ether (MTBE). It is also a clean and efficient liquid fuel with broad application prospects in the energy sector. The catalytic hydrogenation of CO2 to methanol is one of the effective ways to utilize CO2 resources. However, due to the stable molecular structure and inert chemical properties of CO2, activation is difficult, and the reaction is thermodynamically limited (methanol production is exothermic; while low temperatures are thermodynamically favorable for methanol production, they are unfavorable for CO2 activation), resulting in low reaction conversion and methanol selectivity. Therefore, developing efficient and stable catalysts is crucial for the industrial application of CO2 hydrogenation to methanol. However, among related technologies, the catalysts prepared for CO2 hydrogenation to methanol exhibit low catalytic activity and poor stability. Summary of the Invention
[0003] This application aims to provide a method for preparing a catalyst for the hydrogenation of carbon dioxide to methanol and an electronic device, at least to solve the problems of low catalytic activity and poor stability of the prepared catalyst for the hydrogenation of carbon dioxide to methanol.
[0004] To solve the above-mentioned technical problems, this application is implemented as follows: In a first aspect, embodiments of this application provide a method for preparing a catalyst for the hydrogenation of carbon dioxide to methanol, the method comprising: Provide copper foam carrier; Provide a nitrate-based copper salt and a nitrate-based zinc salt, and dissolve the nitrate-based copper salt and the nitrate-based zinc salt to form an initial solution; An alkaline solution is added to the initial solution to make the pH value of the initial solution greater than 7, thereby obtaining an intermediate solution; The copper foam carrier and the intermediate solution are placed in a hydrothermal reactor, the intermediate solution is in contact with the copper foam carrier, and a reducing agent is added to the hydrothermal reactor. The hydrothermal reactor is heated, and after heating is completed, the powder adhering to the surface of the foamed copper carrier and the powder at the bottom of the hydrothermal reactor are removed and collected. The collected copper foam support and powder are heated to obtain a catalyst for the hydrogenation of carbon dioxide to produce methanol.
[0005] Optionally, before providing a nitrate-based copper salt and a nitrate-based zinc salt, and dissolving the nitrate-based copper salt and the nitrate-based zinc salt to form an initial solution, the preparation method further includes: Clean the impurities from the surface of the foamed copper carrier to obtain a pretreated foamed copper carrier; The step of placing the foamed copper carrier and the intermediate solution in a hydrothermal reactor includes: The pretreated copper foam carrier and the intermediate solution are placed in the hydrothermal reactor.
[0006] Optionally, cleaning impurities from the surface of the foamed copper carrier to obtain a pretreated foamed copper carrier includes: The foamed copper carrier was rinsed with deionized water; The rinsed copper foam carrier was placed in an acetone solution and subjected to ultrasonic treatment to obtain the initially treated copper foam carrier. The initial treated copper foam carrier was rinsed with deionized water; The rinsed copper foam carrier is placed in acid and subjected to ultrasonic treatment to obtain an intermediate-treated copper foam carrier. The intermediate-treated copper foam carrier is rinsed alternately with ethanol and deionized water, and then placed in a drying device for drying to obtain a pretreated copper foam carrier.
[0007] Optionally, the copper salt and zinc salt of the nitrate system are dissolved to form an initial solution, comprising: The copper salt and zinc salt of the nitrate system are placed in deionized water to dissolve them, thus obtaining a preliminary solution. A complexing agent is added to the initial solution to promote the interaction between the copper salt and the zinc salt of the nitrate system, so that the copper salt and the zinc salt of the nitrate system dissolve to form a suspension, which serves as the initial solution.
[0008] Optionally, the complexing agent includes at least one of urea and disodium ethylenediaminetetraacetate.
[0009] Optionally, before placing the foamed copper carrier and the intermediate solution in a hydrothermal reactor, the preparation method further includes: Add anhydrous ethanol to the intermediate solution; The step of placing the foamed copper carrier and the intermediate solution in a hydrothermal reactor includes: The foamed copper carrier and the intermediate solution containing anhydrous ethanol were placed in the hydrothermal reactor.
[0010] Optionally, the hydrothermal reactor is heated, and after heating is completed, the powder adhering to the surface of the foamed copper carrier and the powder at the bottom of the hydrothermal reactor are removed and collected, including: The hydrothermal reactor is heated for a set time and the temperature in the hydrothermal reactor is within a set temperature range. After heating is completed, the powder adhering to the surface of the foamed copper carrier and the powder at the bottom of the hydrothermal reactor are removed and collected.
[0011] Optionally, the process of heating the collected copper foam support and powder to obtain a catalyst for the hydrogenation of carbon dioxide to methanol includes: The collected copper foam carrier and powder were washed with deionized water, and the pH value of the deionized water after washing the copper foam carrier and powder was measured until the pH value of the deionized water was 7. The cleaned copper foam carrier and powder are heated to obtain a catalyst for the hydrogenation of carbon dioxide to produce methanol.
[0012] Optionally, the step of heating the cleaned copper foam support and powder to obtain a catalyst for the hydrogenation of carbon dioxide to methanol includes: The cleaned foamed copper carrier and powder are placed in a drying device to dry until the powder is dry; The dried copper foam carrier and powder are placed in a heating device in an inert gas environment, and after heating, a catalyst for the hydrogenation of carbon dioxide to produce methanol is obtained.
[0013] Secondly, embodiments of this application provide a catalyst for the hydrogenation of carbon dioxide to methanol, wherein the catalyst is prepared by the preparation method described in any one of the first aspects above.
[0014] In this embodiment, a copper foam support is provided; nitric acid-based copper salts and nitric acid-based zinc salts are provided and dissolved to form an initial solution; an alkaline solution is added to the initial solution to make the pH value of the initial solution greater than 7, resulting in an intermediate solution; the copper foam support and the intermediate solution are placed in a hydrothermal reactor, with the intermediate solution in contact with the copper foam support, and a reducing agent is added to the hydrothermal reactor; the hydrothermal reactor is heated, and after heating, the powder adhering to the surface of the copper foam support and the powder at the bottom of the hydrothermal reactor are removed and collected; the collected copper foam support and powder are heated to obtain a catalyst for the hydrogenation of carbon dioxide to methanol. That is, in this embodiment, the catalyst for the hydrogenation of carbon dioxide to methanol uses a copper foam support as the catalyst carrier and nitric acid-based copper salts and nitric acid-based zinc salts as metal precursors, prepared by a hydrothermal synthesis method. The three-dimensional network framework of the copper foam support provides a large specific surface area, offering uniformly dispersed anchoring points for active components and effectively exposing active sites. This achieves uniform dispersion of copper and zinc active components on the support surface, significantly improving the catalytic efficiency of the carbon dioxide hydrogenation to methanol reaction. Furthermore, the copper foam support exhibits good conductivity and stability, promoting electron transfer during the reaction. It also eliminates the risk of structural collapse at high reaction and calcination temperatures, further enhancing the catalyst's reactivity and stability, thereby significantly increasing the yield of methanol from carbon dioxide hydrogenation. Attached Figure Description
[0015] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a flowchart illustrating a method for preparing a catalyst for the hydrogenation of carbon dioxide to methanol, as provided in an embodiment of this application. Figure 2 This shows an XRD image of the copper foam support used in the catalyst for the hydrogenation of carbon dioxide to methanol according to this application. Figure 3 This shows the XRD image of the catalyst used in this application for the hydrogenation of carbon dioxide to methanol; Figure 4 This shows a SEM image of the catalyst used in the present application for the hydrogenation of carbon dioxide to methanol; Figure 5 This image shows a TEM image of the catalyst used in the hydrogenation of carbon dioxide to methanol according to this application. Figure 6 This image shows a mapping of the catalyst used in the hydrogenation of carbon dioxide to methanol in this application. Figure 7Images showing the catalyst used in this application for the hydrogenation of carbon dioxide to methanol: (a) after hydrothermal reaction, (b) after heating, and (c) after application. Detailed Implementation
[0016] The embodiments of this application will now be described in detail. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.
[0017] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.
[0018] This application provides a method for preparing a catalyst for the hydrogenation of carbon dioxide to methanol, such as... Figure 1 As shown, the preparation method of the catalyst for the hydrogenation of carbon dioxide to methanol includes: Step 101: Provide a copper foam carrier.
[0019] Copper foam, as a carrier, possesses excellent electrical conductivity and mechanical strength, effectively dispersing the active components. The specifications of the copper foam carrier can range from 40 to 110 PPI; the area of the copper foam carrier can be 1 × 1 cm². 2 .
[0020] Step 102: Provide nitrate-based copper salts and nitrate-based zinc salts, and dissolve the nitrate-based copper salts and nitrate-based zinc salts to form an initial solution.
[0021] The copper salt in this nitrate system can be copper nitrate trihydrate. Of course, the copper salt in this nitrate system can also be other types, such as copper nitrate hexahydrate or anhydrous copper nitrate. This application does not limit the specific type of copper salt used.
[0022] In addition, the zinc salt in the nitrate system can be zinc nitrate hexahydrate. Of course, the zinc salt in the nitrate system can also be other types, such as zinc nitrate trihydrate. This application does not limit the specific type of zinc salt in this regard.
[0023] In some implementations, step 102 can be implemented as follows: placing the nitrate-based copper salt and the nitrate-based zinc salt in deionized water to dissolve them and obtain a preliminary solution; adding a complexing agent to the preliminary solution to promote the interaction between the nitrate-based copper salt and the nitrate-based zinc salt, so that the nitrate-based copper salt and the nitrate-based zinc salt dissolve to form a suspension, which serves as the initial solution.
[0024] In this process, after placing the nitrate-based copper salt and zinc salt in deionized water, the mixture can be stirred to completely dissolve them, obtaining a preliminary solution. Then, a complexing agent can be added to the preliminary solution. The complexing agent can promote the interaction between the nitrate-based copper salt and zinc salt, causing them to dissolve and form a suspension. This suspension can then be used as the initial solution.
[0025] It should be noted that, in the embodiments of this application, the complexing agent includes at least one of urea and disodium ethylenediaminetetraacetate. The complexing agent may consist only of urea, or it may consist only of disodium ethylenediaminetetraacetate. Alternatively, the complexing agent may be a combination of urea and disodium ethylenediaminetetraacetate, i.e., a mixture of urea and disodium ethylenediaminetetraacetate used as the complexing agent.
[0026] In some implementations, prior to step 102, the preparation method further includes cleaning impurities from the surface of the foamed copper support to obtain a pretreated foamed copper support. That is, after providing the foamed copper support, impurities on its surface are cleaned to ensure a cleaner foam cylinder surface, preventing impurities from potentially affecting subsequent products and improving the purity of the generated catalyst for the hydrogenation of carbon dioxide to methanol.
[0027] In some implementations, the process of cleaning impurities from the surface of the copper foam carrier to obtain a pretreated copper foam carrier can be as follows: rinsing the copper foam carrier with deionized water; placing the rinsed copper foam carrier in an acetone solution and performing ultrasonic treatment to obtain an initially treated copper foam carrier; rinsing the initially treated copper foam carrier with deionized water; placing the rinsed copper foam carrier in an acid solution and performing ultrasonic treatment to obtain an intermediate treated copper foam carrier; rinsing the intermediate treated copper foam carrier alternately with ethanol and deionized water, and then placing the rinsed copper foam carrier in a drying device for drying to obtain a pretreated copper foam carrier.
[0028] The process involves several steps. First, rinsing the copper foam carrier with deionized water thoroughly cleans its surface, removing larger impurities. Next, the cleaned carrier is placed in an acetone solution and sonicated. Acetone, as an organic solvent, effectively dissolves impurities on the carrier's surface. Sonication further removes and dissolves impurities from the surface and porous structure, ensuring a clean surface. The carrier is then removed from the acetone solution and rinsed with deionized water to remove as much acetone as possible. Finally, the rinsed carrier is placed in an acid solution and sonicated. The acid dissolves oxides on the carrier's surface, further purifying it and ensuring the surface is free of oxides. The copper foam carrier was then removed from the acid solution and rinsed alternately with ethanol and deionized water to ensure that the surface of the copper foam carrier was free of acid. The rinsed copper foam carrier was then placed in a drying device to dry, thus obtaining the pretreated copper foam carrier.
[0029] It should be noted that the acid solution can be a hydrochloric acid solution, and the hydrochloric acid solution can be 0.1~0.5 mol / L. Of course, the acid solution can also be other types, for example, the acid solution can be a nitric acid solution. In this regard, the embodiments of this application do not limit it.
[0030] In addition, when the rinsed copper foam carrier is placed in an acetone solution and subjected to ultrasonic treatment, the duration of ultrasonic treatment can be any value between 10 and 30 minutes. For example, the duration of ultrasonic treatment is 10 minutes, 20 minutes, or 30 minutes. This embodiment of the application does not limit the duration of ultrasonic treatment. The ultrasonic treatment temperature is room temperature.
[0031] In addition, when the rinsed foamed copper carrier is placed in acid and subjected to ultrasonic treatment, the duration of ultrasonic treatment can be any value between 5 and 35 minutes. For example, the duration of ultrasonic treatment is 5 minutes, 10 minutes, 20 minutes, or 35 minutes. This application does not limit the duration of ultrasonic treatment in this regard.
[0032] It should be noted that all ultrasonic treatments were performed at room temperature, i.e., the ultrasonic temperature was room temperature.
[0033] In addition, in the embodiments of this application, when the intermediate treatment foam copper carrier is rinsed alternately with ethanol and deionized water, the number of ethanol and deionized water washing times can be 5 to 10.
[0034] Furthermore, when the rinsed copper foam carrier is placed in a drying device for drying, the temperature in the drying device can be 40~100 °C, and the vacuum drying time can be any value from 1 to 4 hours. For example, the vacuum drying time is 1 hour, 2 hours, or 4 hours. This application does not limit the specific duration of the drying process.
[0035] Step 103: Add an alkaline solution to the initial solution to make the pH value of the initial solution greater than 7, thus obtaining an intermediate solution.
[0036] In this process, after adding an alkaline solution to the initial solution, the pH value of the initial solution can be measured. If the pH value is less than 7, the alkaline solution is added again until the pH value of the initial solution is greater than 7, thus obtaining the intermediate solution.
[0037] It should be noted that the alkaline solution can be a NaOH solution, but it can also be other types, such as a NaHCO3 solution. The specific type of alkaline solution is not limited in this embodiment. When the alkaline solution is a NaOH solution, the concentration of the NaOH solution can be 1~2.5 mol / L.
[0038] Step 104: Place the copper foam carrier and intermediate solution in a hydrothermal reactor, with the intermediate solution in contact with the copper foam carrier, and add a reducing agent to the hydrothermal reactor.
[0039] In this process, a copper foam carrier and an intermediate solution are placed in a hydrothermal reactor with a polytetrafluoroethylene liner. The copper foam carrier adheres to the inner wall of the hydrothermal reactor, ensuring that the copper foam carrier and the intermediate solution are in full contact. Then, a reducing agent is added to the hydrothermal reactor.
[0040] In addition, the reducing agent can be hydrazine hydrate, but other types are also possible, such as hydroxylamine. The specific type of reducing agent is not limited in this embodiment. When the reducing agent is hydrazine hydrate, the concentration of the hydrazine hydrate solution is 30-80 wt%.
[0041] In addition, after cleaning the impurities on the surface of the foamed copper carrier to obtain the pretreated foamed copper carrier, the pretreated foamed copper carrier and the intermediate solution are placed in the hydrothermal reactor for hydrothermal reaction.
[0042] In some implementations, before step 104, the preparation method further includes adding anhydrous ethanol to the intermediate solution; then, the method of placing the copper foam carrier and the intermediate solution in a hydrothermal reactor can be: placing the copper foam carrier and the intermediate solution with added anhydrous ethanol in the hydrothermal reactor.
[0043] In this process, heating anhydrous ethanol into the intermediate solution increases the polarity of the intermediate solution, promoting the adhesion of two salts in the intermediate solution to the surface of the copper foam carrier, namely, the nitrate-based copper salt and the nitrate-based zinc salt in the intermediate solution to the surface of the copper foam carrier.
[0044] Step 105: Heat the hydrothermal reactor. After heating is complete, remove and collect the powder adhering to the surface of the copper foam carrier and the powder at the bottom of the hydrothermal reactor.
[0045] The hydrothermal reactor can be placed in a heating device, such as an oven, to carry out the hydrothermal reaction. After heating is complete, the powder adhering to the surface of the copper foam carrier and the powder at the bottom of the hydrothermal reactor are removed and collected to obtain the collected powder.
[0046] In some implementations, step 105 can be implemented by: heating the hydrothermal reactor for a set time period and keeping the temperature in the hydrothermal reactor within a set temperature range; and after heating is completed, removing and collecting the powder adhering to the surface of the copper foam carrier and the powder at the bottom of the hydrothermal reactor.
[0047] The set duration can be 8 to 14 hours, and the set temperature can be 80 to 180 ℃.
[0048] Step 106: The collected copper foam support and powder are heated to obtain a catalyst for the hydrogenation of carbon dioxide to produce methanol.
[0049] Once the copper foam carrier and powder in the hydrothermal reactor are collected, the collected copper foam carrier and powder can be heated to obtain a catalyst for the hydrogenation of carbon dioxide to produce methanol.
[0050] In some implementations, step 106 can be implemented as follows: the collected copper foam support and powder are washed with deionized water, and the pH value of the deionized water after washing the copper foam support and powder is detected until the pH value of the deionized water is 7; the washed copper foam support and powder are heated to obtain a catalyst for the preparation of methanol by carbon dioxide hydrogenation.
[0051] The process involves washing the collected copper foam support and powder with deionized water, and then measuring the pH value of the deionized water until it reaches a pH of 7. This ensures that the surface of the washed copper foam support and powder is free of impurities. The washed copper foam support and powder are then heated to obtain a catalyst for the hydrogenation of carbon dioxide to methanol. This process ensures the purity of the resulting catalyst, demonstrating that washing the collected copper foam support and powder with deionized water improves the purity of the generated catalyst.
[0052] In addition, in some implementations, heating the cleaned copper foam support and powder to obtain a catalyst for the hydrogenation of carbon dioxide to methanol can be achieved by: placing the cleaned copper foam support and powder in a drying device to dry until the copper foam support and powder are dry; placing the dried copper foam support and powder in a heating device in an inert gas environment, and obtaining a catalyst for the hydrogenation of carbon dioxide to methanol after heating.
[0053] The drying device can be an oven, with a drying time of 4 to 12 hours and a drying temperature of 60 to 140 °C. The heating device can be a tube furnace, with a temperature of 300 to 800 °C and a heating time of 1 to 6 hours. The inert gas can be nitrogen or argon.
[0054] In addition, the prepared catalyst for the hydrogenation of carbon dioxide to methanol can also be applied in this embodiment. Specifically, the prepared catalyst is uniformly packed into the middle of a fixed-bed reaction tube, and both ends of the reaction tube are fixed with quartz wool. The reaction tube is then installed in a fixed-bed reaction apparatus, nitrogen gas is introduced, and the airtightness of the apparatus is checked. After the airtightness is qualified, a mixture of hydrogen and nitrogen gas is introduced, and the gas flow rate is controlled at 20~90 mL / min. The temperature of the reaction tube is raised to 200~600 ℃ at a heating rate of 2~5 ℃ / min, and the reduction is maintained at this temperature for 1~6 h. After the reduction is completed, the reaction temperature is adjusted to 200~380 ℃, and the reaction pressure is adjusted to 1~8 ℃. A reaction mixture of hydrogen, nitrogen, and carbon dioxide is introduced at a pressure of MPa to carry out the reaction of carbon dioxide hydrogenation to prepare methanol. During the reaction, the contents of gaseous products such as methanol (CH3OH), carbon monoxide (CO), carbon dioxide (CO2), and methane (CH4) at the outlet are analyzed by gas chromatography thermal conductivity detector. Samples are taken periodically for analysis to calculate the carbon dioxide conversion rate and methanol selectivity, and to evaluate the catalytic performance of the catalyst.
[0055] When checking the airtightness of the device, the pressure of the nitrogen cylinder can be adjusted to raise the pressure in the reaction tube to 3 MPa, the valve can be closed, and the device can be left to stand for 1 hour. The pressure gauge reading can be observed. If the pressure drop does not exceed 0.05 MPa, the airtightness is considered to be qualified.
[0056] The following is a performance comparison of the catalysts prepared in the embodiments of this application for the production of methanol by carbon dioxide hydrogenation: Specifically, catalysts for the hydrogenation of carbon dioxide to methanol can be prepared in different dosages and tested, as follows: Example 1: 0.24 g of copper nitrate trihydrate and 0.59 g of zinc nitrate hexahydrate were accurately weighed using an electronic balance and added to a 50 mL beaker containing 20 mL of deionized water. The beaker was placed on a magnetic stirrer and stirred for 40 min to completely dissolve the metal salts. Then, 0.61 g of urea was added, and stirring continued for 30 min to form a homogeneous and stable suspension. Under continuous stirring, 20 mL of 1.25 M NaOH solution was pipetted and slowly added dropwise to the suspension at a rate of 1.5 mL / min. After the addition was complete, stirring continued for 15 min. Then, 10 mL of anhydrous ethanol was added, and stirring continued for 20 min to obtain a homogeneous mixed solution. The mixed solution was slowly transferred to a 100 mL polytetrafluoroethylene-lined hydrothermal reactor. A copper foam support, after being ultrasonically treated with acetone, deoxidized with hydrochloric acid, and alternately washed with ethanol and deionized water and then vacuum dried, was attached to the inner wall of a hydrothermal reactor, ensuring full contact between the surface of the copper foam support and the solution. Then, 10 mL of a 50 wt% hydrazine hydrate solution was added, the reactor lid was tightened, and the reactor was placed in an oven at 120 °C for 12 h. After the reaction, the oven was closed, and the reactor was allowed to cool naturally to room temperature. The lid was then opened, and the copper foam support with attached powder and the precipitated powder at the bottom of the reactor were collected. The collected support and powder were placed in a beaker and repeatedly washed with deionized water. After each wash, the precipitate was allowed to stand, and the supernatant was poured off. This washing process was repeated until the pH of the supernatant reached 7. The washed product was transferred to a magnetic boat and placed in a forced-air drying oven at 60 °C for 6 h to obtain a dried solid product. The dried solid product was placed in a tube furnace, a heating program was set, and high-purity argon gas was introduced to purge the air from the furnace tube. The inert gas flow rate was 20 mL / min, the purging time was 1 h, and the heating program was to heat to 350 °C at a heating rate of 5 °C / min and hold the temperature for 1 h. After that, argon gas was continued to be introduced until the furnace tube temperature naturally cooled to room temperature. The magnetic boat was then removed, and the catalyst for the preparation of methanol by carbon dioxide hydrogenation was obtained, denoted as Cat-1.
[0057] Example 2: Using the same method as Example 1, and under the same conditions as Example 1, the difference is that the amount of copper nitrate trihydrate added is 0.36 g and the amount of zinc nitrate hexahydrate added is 0.45 g, to obtain a catalyst for the hydrogenation of carbon dioxide to prepare methanol, denoted as Cat-2.
[0058] Example 3: Using the same method as Example 1, and under the same conditions as Example 1, the difference is that the amount of copper nitrate trihydrate added is 0.48 g and the amount of zinc nitrate hexahydrate added is 0.30 g, to obtain a catalyst for the hydrogenation of carbon dioxide to methanol, denoted as Cat-3.
[0059] Example 4: Using the same method as Example 1, and under the same conditions as Example 1, except that the hydrothermal reaction temperature was 100 °C and the reaction time was 12 h, a catalyst for the hydrogenation of carbon dioxide to prepare methanol was obtained, denoted as Cat-4.
[0060] The performance of the catalysts for the production of methanol by carbon dioxide hydrogenation obtained in the above four examples was then tested, as follows: Take 0.2 g of catalyst and pour the granules into a stainless steel reaction tube with an inner diameter of 10 mm. While filling, tap the tube firmly with a rubber mallet to prevent bed drop during the reaction. Plug the tube with quartz wool at both ends. Install the reaction tube, open the valve, and adjust the cylinder pressure to raise the pressure inside the reaction tube to 3 MPa. Close the cylinder pressure reducing valve outlet and the reactor outlet valve. Let it stand for 1 h and observe that the reactor pressure gauge reading does not change. If there is no change, the device can be considered to have good airtightness. After the airtightness is qualified, open the nitrogen and hydrogen cylinder valves, adjust the gas flow controller, and purge with 30 mL / min of 10% H2 / N2 for 30 min to remove the N2 used for leak testing. The reactor was heated to 300℃ at a rate of 2℃ / min and maintained for 2 h for catalyst reduction. After reduction, the reaction temperature was adjusted to 240℃. After cooling, the CO2 cylinder valve was opened, and the gas flow controller was adjusted to introduce reaction gas (composition: N2:H2:CO2 = 30:30:10, unit: mL / min) for CO2 hydrogenation to methanol production. After the reaction started, samples were taken every hour, and the composition of gaseous products such as CH3OH, CO, CO2, and CH4 in the outlet gas was analyzed by online gas chromatography. The CO2 conversion rate and methanol selectivity were calculated, and the test results are shown in Table 1.
[0061] Table 1 catalyst <![CDATA[CO2 conversion rate / %]]> Methanol selectivity / % Methanol yield / % Cat-1 27.41 85.84 23.53 Cat-2 28.62 80.53 23.05 Cat-3 26.85 83.99 22.55 Cat-4 20.67 79.55 16.44 As shown in Table 1, the catalysts prepared using the method of this application exhibit high CO2 conversion and high methanol selectivity. Among them, the Cat-1 catalyst prepared in Example 1 demonstrates the best catalytic performance, with a CO2 conversion of 27.41%, a methanol selectivity of 85.84%, and a methanol yield of 23.53%, significantly superior to the catalysts prepared in other examples. This is because the copper-zinc molar ratio of 1:2 in Example 1 forms the most stable copper-zinc composite active phase, resulting in the strongest synergistic effect between the two, thus exhibiting the optimal CO2 conversion and methanol selectivity.
[0062] In addition, the structure of the catalyst for the hydrogenation of carbon dioxide to methanol prepared in the embodiments of this application can be further characterized, specifically: like Figure 2 As shown, Figure 2 The image shows the XRD pattern of the copper foam support used in the catalyst for the hydrogenation of carbon dioxide to methanol in this application. Figure 2 The two characteristic peaks at 43.3° and 50.5° correspond to Cu. 0 The (111) and (200) crystal planes indicate that the foamed copper carrier skeleton maintains a metallic copper structure.
[0063] like Figure 3 As shown, Figure 3 This is an XRD image of the catalyst used in this application for the hydrogenation of carbon dioxide to methanol. Figure 3 The three characteristic peaks at 43.3°, 50.5°, and 74.1° correspond to Cu. 0 The (111), (200), and (220) crystal planes indicate that the copper foam carrier skeleton still retains the metallic copper structure after hydrothermal treatment and calcination, and has not been completely oxidized. The 31.8°, 34.4°, 36.3°, 47.5°, 56.6°, 62.9°, and 67.9° correspond to the (100), (002), (101), (102), (110), (103), and (112) crystal planes of ZnO. The broadening of the peak shape indicates that the ZnO grain size is small and highly dispersed on the Cu surface.
[0064] like Figure 4 As shown, Figure 4 SEM images of the catalyst used in this application for the hydrogenation of carbon dioxide to methanol. (From...) Figure 4 As can be seen from the low-magnification SEM image, the copper foam support skeleton is intact and retains its three-dimensional porous structure, indicating that the copper foam support skeleton did not collapse during the hydrothermal and calcination process. In the high-magnification SEM image, spherical / ellipsoidal nanoparticles are uniformly distributed on the surface of the copper foam support without obvious agglomeration, indicating that the active layer is uniformly coated. A dense nanoparticle layer is visible on the surface without cracks or peeling, indicating that the Cu-Zn active phase is firmly bonded to the copper foam support.
[0065] like Figure 5 As shown, Figure 5 This is a TEM image of the catalyst used in the hydrogenation of carbon dioxide to methanol according to this application. (From...) Figure 5 As can be seen in the low-magnification TEM image, thin flake-like fragments are visible on the surface of the copper foam support skeleton, consistent with the SEM image, indicating that the active layer is uniformly coated.
[0066] like Figure 6 As shown, Figure 6 This is a mapping image of the catalyst used in the hydrogenation of carbon dioxide to methanol in this application. From... Figure 6 It can be seen that several elements such as Cu, Zn, O, and N are present on the catalyst surface and are uniformly distributed on the catalyst surface, indicating that the active components are well dispersed on the support surface, providing sufficient active sites for the catalytic reaction. Among them, the presence of Zn indicates that Zn was successfully loaded onto the copper foam support, Cu comes from the copper foam support and the surface-coated Cu, and the presence of O is because the Cu and Zn elements loaded on the catalyst have undergone oxidation.
[0067] like Figure 7 As shown, Figure 7 Images of the catalyst used in this application for the hydrogenation of carbon dioxide to methanol (a) after hydrothermal reaction, (b) after heating, and (c) after application, from... Figure 7 It can be seen that after the catalyst is applied, the copper oxide attached to the surface and inside the copper foam support is reduced to copper, and the copper foam support still maintains its three-dimensional porous framework.
[0068] In this embodiment, a copper foam support is provided; nitric acid-based copper salts and nitric acid-based zinc salts are provided and dissolved to form an initial solution; an alkaline solution is added to the initial solution to make the pH value of the initial solution greater than 7, resulting in an intermediate solution; the copper foam support and the intermediate solution are placed in a hydrothermal reactor, with the intermediate solution in contact with the copper foam support, and a reducing agent is added to the hydrothermal reactor; the hydrothermal reactor is heated, and after heating, the powder adhering to the surface of the copper foam support and the powder at the bottom of the hydrothermal reactor are removed and collected; the collected copper foam support and powder are heated to obtain a catalyst for the hydrogenation of carbon dioxide to methanol. That is, in this embodiment, the catalyst for the hydrogenation of carbon dioxide to methanol uses a copper foam support as the catalyst carrier and nitric acid-based copper salts and nitric acid-based zinc salts as metal precursors, prepared by a hydrothermal synthesis method. The three-dimensional network framework of the copper foam support provides a large specific surface area, offering uniformly dispersed anchoring points for active components and effectively exposing active sites. This achieves uniform dispersion of copper and zinc active components on the support surface, significantly improving the catalytic efficiency of the carbon dioxide hydrogenation to methanol reaction. Furthermore, the copper foam support exhibits good conductivity and stability, promoting electron transfer during the reaction. It also eliminates the risk of structural collapse at high reaction and calcination temperatures, further enhancing the catalyst's reactivity and stability, thereby significantly increasing the yield of methanol from carbon dioxide hydrogenation.
[0069] In addition, the catalyst prepared by the method of this application exhibits high carbon dioxide conversion rate and methanol selectivity in the reaction of carbon dioxide hydrogenation to methanol, and the catalyst has excellent stability and recyclability.
[0070] This application provides a catalyst for the hydrogenation of carbon dioxide to methanol, which is prepared by the method described in the above embodiments. The catalyst contains a copper foam support.
[0071] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0072] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.
Claims
1. A method for preparing a catalyst for the hydrocarbon monoxide of carbon dioxide, characterized by, The method for preparing the catalyst for the hydrogenation of carbon dioxide to methanol includes: Provide copper foam carrier; Provide a nitrate-based copper salt and a nitrate-based zinc salt, and dissolve the nitrate-based copper salt and the nitrate-based zinc salt to form an initial solution; An alkaline solution is added to the initial solution to make the pH value of the initial solution greater than 7, thereby obtaining an intermediate solution; The copper foam carrier and the intermediate solution are placed in a hydrothermal reactor, the intermediate solution is in contact with the copper foam carrier, and a reducing agent is added to the hydrothermal reactor. The hydrothermal reactor is heated, and after heating is completed, the powder adhering to the surface of the foamed copper carrier and the powder at the bottom of the hydrothermal reactor are removed and collected. The collected copper foam support and powder are heated to obtain a catalyst for the hydrogenation of carbon dioxide to produce methanol.
2. The method for preparing a catalyst for carbon dioxide hydrogenation to methanol according to claim 1, characterized by, Before providing a nitrate-based copper salt and a nitrate-based zinc salt, and dissolving the nitrate-based copper salt and the nitrate-based zinc salt to form an initial solution, the preparation method further includes: Clean the impurities from the surface of the foamed copper carrier to obtain a pretreated foamed copper carrier; The step of placing the foamed copper carrier and the intermediate solution in a hydrothermal reactor includes: The pretreated copper foam carrier and the intermediate solution are placed in the hydrothermal reactor.
3. The method for preparing a catalyst for carbon dioxide hydrogenation to methanol according to claim 2, characterized by, The process of cleaning impurities from the surface of the foamed copper carrier to obtain a pretreated foamed copper carrier includes: The foamed copper carrier was rinsed with deionized water; The rinsed copper foam carrier was placed in an acetone solution and subjected to ultrasonic treatment to obtain the initially treated copper foam carrier. The initial treated copper foam carrier was rinsed with deionized water; The rinsed copper foam carrier is placed in acid and subjected to ultrasonic treatment to obtain an intermediate-treated copper foam carrier. The intermediate-treated copper foam carrier is rinsed alternately with ethanol and deionized water, and then placed in a drying device for drying to obtain a pretreated copper foam carrier.
4. The method for preparing a catalyst for carbon dioxide hydrogenation to methanol according to any one of claims 1 to 3, characterized by, Dissolving the copper salt and zinc salt of the nitrate system to form an initial solution, comprising: The copper salt and zinc salt of the nitrate system are placed in deionized water to dissolve them, thus obtaining a preliminary solution. A complexing agent is added to the initial solution to promote the interaction between the copper salt and the zinc salt of the nitrate system, so that the copper salt and the zinc salt of the nitrate system dissolve to form a suspension, which serves as the initial solution.
5. The method for preparing a catalyst for carbon dioxide hydrogenation to methanol according to claim 4, characterized by, The complexing agent includes at least one of urea and disodium ethylenediaminetetraacetate.
6. The method for preparing a catalyst for carbon dioxide hydrogenation to methanol according to any one of claims 1 to 3, characterized by, Before placing the foamed copper carrier and the intermediate solution in a hydrothermal reactor, the preparation method further includes: Add anhydrous ethanol to the intermediate solution; The step of placing the foamed copper carrier and the intermediate solution in a hydrothermal reactor includes: The foamed copper carrier and the intermediate solution containing anhydrous ethanol were placed in the hydrothermal reactor.
7. The method for preparing a catalyst for the hydrogenation of carbon dioxide to methanol according to any one of claims 1-3, characterized in that, The hydrothermal reactor is heated. After heating is complete, the powder adhering to the surface of the foamed copper carrier and the powder at the bottom of the hydrothermal reactor are removed and collected, including: The hydrothermal reactor is heated for a set time and the temperature in the hydrothermal reactor is within a set temperature range. After heating is completed, the powder adhering to the surface of the foamed copper carrier and the powder at the bottom of the hydrothermal reactor are removed and collected.
8. The method for preparing a catalyst for carbon dioxide hydrogenation to methanol according to any one of claims 1 to 3, characterized by, The process of heating the collected copper foam support and powder to obtain a catalyst for the hydrogenation of carbon dioxide to methanol includes: The collected copper foam carrier and powder were washed with deionized water, and the pH value of the deionized water after washing the copper foam carrier and powder was measured until the pH value of the deionized water was 7. The cleaned copper foam carrier and powder are heated to obtain a catalyst for the hydrogenation of carbon dioxide to produce methanol.
9. The method for preparing a catalyst for carbon dioxide hydrogenation to methanol according to claim 8, characterized by, The process involves heating the cleaned copper foam support and powder to obtain a catalyst for the hydrogenation of carbon dioxide to methanol, comprising: The cleaned foamed copper carrier and powder are placed in a drying device to dry until the powder is dry; The dried copper foam carrier and powder are placed in a heating device in an inert gas environment, and after heating, a catalyst for the hydrogenation of carbon dioxide to produce methanol is obtained.
10. A catalyst for the hydrogenation of carbon dioxide to methanol, characterized in that, The catalyst is prepared by the preparation method according to any one of claims 1-9.