A Cu-based catalyst for catalytic conversion of carbon dioxide and its preparation method

Abstract

The present invention discloses a Cu-based catalyst for catalytic conversion of carbon dioxide and a preparation method thereof. The preparation method comprises the following steps: S1: preparing a precursor solution providing a molybdenum source, mixing the precursor solution with an organic matter, stirring evenly, and obtaining a mixture; S2: drying the mixture, and then subjecting it to high-temperature calcination treatment under a pure hydrogen atmosphere to obtain a Mo2C carrier; S3: dispersing the Mo2C carrier into pure water, and dropwise adding a metal cation salt solution providing a copper source and a cerium source, adjusting the pH to alkaline, stirring, aging, and filtering to obtain a precipitate; S4: placing the precipitate in a vacuum and drying it, and then calcining it under a pure hydrogen atmosphere to obtain a Cu-CeO2 / Mo2C catalyst. The present invention can produce a Cu-based catalyst for catalytic conversion of carbon dioxide with high CO2 conversion rate and high CO selectivity, and can provide technical support for CO2 catalytic conversion.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, and in particular to a Cu-based catalyst for catalytic conversion of carbon dioxide and a preparation method thereof. Background Art

[0002] At present, my country's energy structure in the short term is still dominated by fossil energy. The concentration of CO2 in the atmosphere will continue to rise for a long time in the future. The resulting greenhouse effect will continue to aggravate a series of environmental problems such as global warming. In the chemical industry, synthetic fuels and most chemicals are produced from synthesis gas, but the industrial application of directly using CO2 to produce high-value-added fuels and chemicals is lacking. Therefore, the current use of chemical technology to directly catalytically convert captured CO2 into valuable chemical raw materials such as methanol, methane, and CO is of great significance for "carbon emission reduction and carbon sink enhancement". Among them, the hydrogenation of CO2 to generate synthesis gas, and then further conversion to higher-value-added hydrocarbon products through the Fischer-Tropsch reaction, is one of the most efficient CO2 catalytic conversion technologies with practical application potential.

[0003] The key to improving the performance of reverse water gas shift (RWGS) reaction lies in the design and synthesis of high-performance catalytic materials. Among the most widely used Cu-based catalytic materials, the stability of the active interface structure is the key to restricting the performance of the catalyst. In order to construct a high-performance catalyst interface structure, it is of great significance to select a suitable support material to enhance the interaction between the metal and the support. CeO2 is the most typical rare earth oxide because of its abundant source and the presence of Ce under different reaction conditions. 3+ To Ce 4+ Due to its reversible transformation and unique redox capabilities, CeO2 is widely used as an excellent support for supported catalysts and has broad application prospects. The abundant surface oxygen vacancies created by CeO2 provide favorable conditions for the anchoring of active metal Cu species, the construction of high-performance catalyst interface structures, and the activation of CO2 molecules. The well-dispersed metal Cu particles further promote the effective activation and dissociation of H2 molecules. Therefore, supported Cu-CeO2-based catalytic materials have great potential for application in CO2 hydrogenation reactions.

[0004] However, because the RWGS reaction is endothermic, high temperatures favor the formation of CO. However, the aforementioned Cu-CeO2-based catalysts exhibit poor stability and resistance to sintering at high temperatures, leading to their easy deactivation, which severely impacts catalytic performance. Therefore, constructing a stable Cu-CeO2-based catalyst interface and improving the long-term high-temperature stability of Cu-based catalytic materials have become pressing challenges. Summary of the Invention

[0005] In view of the above problems, the present invention aims to provide a Cu-based catalyst for catalytic conversion of carbon dioxide and a preparation method thereof.

[0006] The technical solutions of the present invention are as follows:

[0007] In one aspect, a method for preparing a Cu-based catalyst for catalytic conversion of carbon dioxide is provided, comprising the following steps:

[0008] S1: preparing a precursor solution for providing a molybdenum source, and mixing the precursor solution with an organic matter, stirring uniformly to obtain a mixture;

[0009] S2: drying the mixture, and then calcining it at high temperature under a pure hydrogen atmosphere to obtain a Mo2C carrier;

[0010] S3: dispersing the Mo2C support into pure water, and dropping a metal cation salt aqueous solution providing a copper source and a cerium source, adjusting the pH to alkaline, stirring, aging, and filtering to obtain a precipitate;

[0011] S4: drying the precipitate in a vacuum, and then calcining the precipitate under a pure hydrogen atmosphere to obtain a Cu-CeO2 / Mo2C catalyst.

[0012] Preferably, in step S1, the solute of the precursor solution is any one or more of ammonium molybdate tetrahydrate, sodium molybdate, and molybdenum chloride.

[0013] Preferably, in step S1, the organic matter is any one or more of sucrose, glucose, maltose, lactose, fructose, cellobiose, D-xylose, xylitol, erythritol, and sorbitol.

[0014] Preferably, in step S1, the molar ratio of the solute in the precursor solution to the organic matter is 1:1-10.

[0015] Preferably, in step S1, when stirring is performed, the temperature is 10-30°C and the time is 0.1-5h; in step S2, when drying is performed, the temperature is 50-130°C and the time is 10-48h; in step S2, when high-temperature calcination is performed, the heating rate is 1-10°C / min, the temperature is 400-600°C, and the time is 10-48h.

[0016] Preferably, in step S3, the solute of the metal cation salt solution is a mixed salt of a copper salt and a cerium salt, the copper salt is any one or more of copper nitrate trihydrate, copper chloride dihydrate, copper sulfate pentahydrate, and copper acetate, and the cerium salt is any one or more of cerium nitrate hexahydrate, cerium chloride heptahydrate, cerous sulfate, cerium acetate, and ammonium ceric nitrate; the molar ratio of the copper salt, the cerium salt, and the Mo2C carrier is 1:1:50-30:30:50.

[0017] Preferably, in step S3, an alkaline solution with a concentration of 0.1-15 mol / L is used to adjust the pH to 8-10, and the solute of the alkaline solution is any one or more of urea, ammonium carbonate, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, ammonia water, sodium hydroxide, and potassium hydroxide.

[0018] Preferably, in step S3, the stirring is performed at a temperature of 10-80° C. and the time is 0.1-2 h; and the aging is performed at a temperature of 10-80° C. and the time is 0.1-2 h.

[0019] Preferably, in step S4, during drying, the temperature is 50-100°C and the time is 4-48 hours; during calcination, the heating rate is 1-10°C / min, the temperature is 400-800°C and the time is 1-8 hours.

[0020] On the other hand, a Cu-based catalyst for catalytic conversion of carbon dioxide is also provided, which is prepared using any of the above-mentioned methods for preparing a Cu-based catalyst for catalytic conversion of carbon dioxide.

[0021] The beneficial effects of the present invention are:

[0022] (1) The present invention utilizes transition metal carbides as carriers, simultaneously dispersing active metal Cu and nanoparticles of CeO2 to construct a novel bimetallic oxide-carbide composite structure. The interaction between the three components, Cu, CeO2, and Mo2C, allows the active sites to synergistically promote the reaction, significantly improving the catalyst's adsorption, activation, and conversion efficiency for reactants in the reverse water-gas reaction. The unique active site network structure achieves highly efficient catalytic performance.

[0023] (2) The present invention prepares a multi-active site synergistic Cu-CeO2 / Mo2C catalyst through a simple synthetic method. Metallic Cu species and CeO2 nanoparticles are highly dispersed on the Mo2C support, constructing a stable catalytically active interface. Cu, as an active metal, has good hydrogenation activity and plays an important role in H2 dissociation; CeO2 provides abundant oxygen vacancies, promoting the adsorption and activation of CO2; and Mo2C, as a support, has a unique electronic structure and catalytic properties, which helps to improve the activity and selectivity of the RWGS reaction.

[0024] (3) The catalyst prepared by the present invention was applied to the reverse water gas reaction and showed good catalytic activity under harsh reaction conditions (600 ° C, mass space velocity GHSV of 200,000 mL·g cat -1 ·h -1), achieving a CO2 conversion rate of 65.12% and a CO selectivity of 100%, demonstrating significant potential for industrial application. Compared to conventional catalysts, this system also achieves higher catalytic activity at a lower temperature (400°C), achieving a CO2 conversion rate of 32.09%, thereby reducing energy consumption and equipment requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 This is the XRD pattern of Example 3.

[0027] Figure 2 Schematic diagram of the CO2 conversion test results of the catalysts of each example at different temperatures; (a) is the CO2 conversion test results of Examples 1-5 at a mass space velocity GHSV of 200,000 mL·g cat -1 ·h -1 CO2 conversion rate under the condition of (b) is the ... cat -1 ·h -1 The CO2 conversion rate under .

[0028] Figure 3 For Example 3, at 600°C and a mass space velocity (GHSV) of 200,000 mL·g cat -1 ·h -1 Schematic diagram of the stability test results below. DETAILED DESCRIPTION

[0029] The present invention is further described below with reference to the accompanying drawings and examples. It should be noted that, in the absence of conflict, the embodiments in this application and the technical features in the embodiments can be combined with each other. It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meanings as those commonly understood by those of ordinary skill in the art to which this application belongs. The use of similar words such as "include" or "comprising" in the present invention means that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0030] In one aspect, the present invention provides a method for preparing a Cu-based catalyst for catalytic conversion of carbon dioxide, comprising the following steps:

[0031] S1: preparing a precursor solution for providing a molybdenum source, and mixing the precursor solution with an organic matter, stirring them uniformly to obtain a mixture.

[0032] In a specific embodiment, the solute of the precursor solution is any one or more of ammonium molybdate tetrahydrate, sodium molybdate, and molybdenum chloride, and the organic matter is any one or more of sucrose, glucose, maltose, lactose, fructose, cellobiose, D-xylose, xylitol, erythritol, and sorbitol, and the molar ratio of the solute of the precursor solution to the organic matter is 1:1-10.

[0033] In a specific embodiment, the stirring is performed at a temperature of 10-30° C. and for a time of 0.1-5 h.

[0034] S2: drying the mixture, and then calcining it at high temperature under a pure hydrogen atmosphere to obtain a Mo2C carrier.

[0035] In a specific embodiment, the drying process is performed at a temperature of 50-130° C. for 10-48 hours; and the high-temperature calcination process is performed at a heating rate of 1-10° C. / min, a temperature of 400-600° C. for 10-48 hours.

[0036] S3: The Mo2C carrier is dispersed in pure water, and a metal cation salt aqueous solution providing a copper source and a cerium source is added dropwise, the pH is adjusted to alkaline, and the mixture is stirred, aged, and filtered to obtain a precipitate.

[0037] In a specific embodiment, the solute of the metal cation salt solution is a mixed salt of a copper salt and a cerium salt, the copper salt is any one or more of copper nitrate trihydrate, copper chloride dihydrate, copper sulfate pentahydrate, and copper acetate, and the cerium salt is any one or more of cerium nitrate hexahydrate, cerium chloride heptahydrate, cerous sulfate, cerium acetate, and ammonium ceric nitrate; the molar ratio of the copper salt, the cerium salt, and the Mo2C carrier is 1:1:50-30:30:50.

[0038] In a specific embodiment, the pH is adjusted to 8-10 using an alkaline solution with a concentration of 0.1-15 mol / L, and the solute of the alkaline solution is any one or more of urea, ammonium carbonate, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, ammonia water, sodium hydroxide, and potassium hydroxide.

[0039] In a specific embodiment, the stirring is performed at a temperature of 10-80° C. and a time of 0.1-2 h; and the aging is performed at a temperature of 10-80° C. and a time of 0.1-2 h.

[0040] S4: drying the precipitate in a vacuum, and then calcining the precipitate under a pure hydrogen atmosphere to obtain a Cu-CeO2 / Mo2C catalyst.

[0041] In a specific embodiment, the drying process is carried out at a temperature of 50-100° C. and a time of 4-48 h; and the calcination process is carried out at a heating rate of 1-10° C. / min, a temperature of 400-800° C. and a time of 1-8 h.

[0042] In the present invention, the introduction of Mo2C enables the construction of a stable Cu-CeO2 catalytic interface. The introduction of carbon into Mo2C provides the material with abundant d-band electrons, significantly enhancing its catalytic activity. Mo2C, used as a catalyst support material, not only helps disperse the active metal and oxide components but also provides ample space and coordination environment for these components, forming a more stable metal-oxide interface structure, improving catalytic reaction performance, and achieving high catalyst stability, earning it the reputation of a "platinum-like catalyst."

[0043] On the other hand, the present invention also provides a Cu-based catalyst for catalytic conversion of carbon dioxide, which is prepared using any of the above-mentioned methods for preparing a Cu-based catalyst for catalytic conversion of carbon dioxide.

[0044] In a specific embodiment, the catalyst of the present invention is used for the reverse water gas shift reaction, and the reduction activation conditions are as follows: the catalyst and quartz sand are loaded into a quartz tube fixed bed reactor, and a hydrogen-containing mixed gas is introduced for reduction, wherein the hydrogen volume percentage of the hydrogen-containing mixed gas is 5-100%, and the remaining gas is nitrogen, argon or helium. The reduction temperature is 300-600°C, the pressure is 0.1-3 MPa, and the mass space velocity is 60,000-500,000 mL·g cat -1 ·h -1 , activation time is 1-10h.

[0045] The evaluation conditions for the reverse water-gas shift reaction are as follows: the reaction gas is introduced, the molar ratio of hydrogen to carbon dioxide in the reaction gas is 9:1-1:1, nitrogen is used as a diluent gas, and the mass space velocity is 60,000-500,000 mL·g cat -1 ·h -1 , the reaction pressure is 0.1-5Mpa, and the reaction temperature is 300-800℃.

[0046] Example 1

[0047] A Cu-based catalyst for catalytic conversion of carbon dioxide is prepared by the following steps:

[0048] (1) 7.4 mmol of ammonium molybdate tetrahydrate was dissolved in 70 mL of deionized water (DI) and stirred at room temperature for 30 min. Then, 15.2 mmol of sucrose was added. The mixed solution was stirred for 0.5 h to obtain a homogeneous solution. The above solution was placed at 110 °C to dry overnight. The dried sample was ground into powder in agate. Finally, it was calcined in pure H2 for 12 h at a high temperature of 500 °C and a heating rate of 10 °C / min to obtain a Mo2C support.

[0049] (2) Take 1g of Mo2C support and disperse it in 50mL of ultrapure water, and stir it at room temperature for 10min. Then, copper chloride dihydrate and cerium chloride heptahydrate are dissolved in 25mL of ultrapure water, and the molar ratio of copper salt, cerium salt and Mo2C support is 3:2:50. Next, the metal cation salt aqueous solution composed of copper chloride dihydrate and cerium chloride heptahydrate is dripped into the dispersion of Mo2C support; at the same time, potassium carbonate solution (0.60mol / L) is added to adjust the pH of the mixed solution to 10, stir it for 20min, age it for 40min, wash it with ultrapure water at room temperature, and then dry it in a vacuum oven at 80℃ for 12h. It is calcined at 500℃ under pure H2 for 12h (heating rate of 5℃ / min). The obtained catalyst is recorded as Cat1.

[0050] Example 2

[0051] A Cu-based catalyst for catalytic conversion of carbon dioxide is prepared by the following steps:

[0052] (1) 3.5 mmol of sodium molybdate was dissolved in 100 mL of deionized water (DI) and stirred at room temperature for 30 min. Then, 9.6 mmol of glucose was added. The mixed solution was stirred for 4 h to obtain a homogeneous solution. The above solution was placed at 110°C to dry overnight. The dried sample was ground into powder in agate. Finally, it was calcined in pure H2 for 15 h at a temperature of 500°C and a heating rate of 10°C / min to obtain a Mo2C support.

[0053] (2) Take 1g of Mo2C support and disperse it in 50mL of ultrapure water, and stir it at room temperature for 10min. Then, copper nitrate trihydrate and cerium nitrate hexahydrate are dissolved in 25mL of ultrapure water, and the molar ratio of copper salt, cerium salt and Mo2C support is 10:4:50. Next, the metal cation salt aqueous solution composed of copper nitrate trihydrate and cerium nitrate hexahydrate is dripped into the dispersion of Mo2C support; at the same time, sodium carbonate solution (0.50mol / L) is added to adjust the pH of the mixed solution to 9, stir it for 25min, age it for 25min, wash it with ultrapure water at room temperature, and then dry it in a vacuum oven at 70℃ for 10h. It is calcined at 500℃ under pure H2 for 9h (heating rate of 5℃ / min). The obtained catalyst is recorded as Cat2.

[0054] Example 3

[0055] A Cu-based catalyst for catalytic conversion of carbon dioxide is prepared by the following steps:

[0056] (1) 7.4 mmol of ammonium molybdate tetrahydrate was dissolved in 70 mL of deionized water (DI) and stirred at room temperature for 30 min. Then, 15.2 mmol of sucrose was added. The mixed solution was stirred for 0.7 h to obtain a homogeneous solution. The above solution was placed at 120 °C to dry overnight. The dried sample was ground into powder in agate. Finally, it was calcined in pure H2 for 20 h at a high temperature of 500 °C and a heating rate of 10 °C / min to obtain a Mo2C support.

[0057] (2) Take 1g of Mo2C support and disperse it in 50mL of ultrapure water, and stir it at room temperature for 10min. Then, copper nitrate trihydrate and cerium nitrate hexahydrate are dissolved in 25mL of ultrapure water, and the molar ratio of copper salt, cerium salt and Mo2C support is 10:3:50. Next, the metal cation salt aqueous solution consisting of copper nitrate trihydrate and cerium nitrate hexahydrate is dripped into the dispersion of Mo2C support; at the same time, sodium bicarbonate solution (0.5mol / L) is added to adjust the pH of the mixed solution to 9, stir for 30min, age for 1h, wash with ultrapure water at room temperature, and then dry in a vacuum oven at 70℃ for 11h. Calcined at 500℃ under pure H2 for 4h (heating rate of 5℃ / min). The obtained catalyst is recorded as Cat3.

[0058] Example 4

[0059] A Cu-based catalyst for catalytic conversion of carbon dioxide is prepared by the following steps:

[0060] (1) 9 mmol of ammonium molybdate tetrahydrate was dissolved in 100 mL of deionized water (DI). After stirring at room temperature for 30 min, 21.3 mmol of maltose was added. The mixed solution was stirred for 2 h to obtain a homogeneous solution. The above solution was placed at 120°C to dry overnight. The dried sample was ground into powder in agate. Finally, it was calcined in pure H2 for 17 h at a high temperature of 500°C and a heating rate of 10°C / min to obtain a Mo2C support.

[0061] (2) Take 1g of Mo2C support and disperse it in 50mL of ultrapure water, and stir it at room temperature for 10min. Then, copper sulfate pentahydrate and cerous sulfate are dissolved in 25mL of ultrapure water, and the molar ratio of copper salt, cerous salt and Mo2C support is 8:5:50. Next, the metal cation salt aqueous solution composed of copper sulfate pentahydrate and cerous sulfate is dripped into the dispersion of Mo2C support; at the same time, potassium bicarbonate solution (1.0mol / L) is added to adjust the pH of the mixed solution to 8, stir for 10min, age for 10min, wash with ultrapure water at room temperature, and then dry in a vacuum oven at 80℃ for 13h. It is calcined at 500℃ under pure H2 for 7h (heating rate of 5℃ / min). The obtained catalyst is recorded as Cat4.

[0062] Example 5

[0063] A Cu-based catalyst for catalytic conversion of carbon dioxide is prepared by the following steps:

[0064] (1) Dissolve 5 mmol of ammonium molybdate tetrahydrate in 80 mL of deionized water (DI) and stir at room temperature for 30 min. Then, add 12.4 mmol of sucrose. Stir the mixed solution for 0.4 h to obtain a homogeneous solution. Place the above solution at 120 °C to dry overnight. The dried sample is ground into powder in agate. Finally, it is calcined in pure H2 for 20 h at a high temperature of 500 °C and a heating rate of 10 °C / min to obtain a Mo2C support.

[0065] (2) 1 g of Mo2C support was dispersed in 50 mL of ultrapure water and stirred at room temperature for 10 min. Then, copper nitrate trihydrate and cerium nitrate hexahydrate were dissolved in 25 mL of ultrapure water, with the molar ratio of copper salt, cerium salt and Mo2C support being 12:3:50. Next, a metal cation salt aqueous solution consisting of copper nitrate trihydrate and cerium nitrate hexahydrate was dripped into the dispersion of Mo2C support; at the same time, ammonia solution (14.0 mol / L) was added to adjust the pH of the mixed solution to 9, stirred for 30 min, aged for 30 min, washed with ultrapure water at room temperature, and then dried in a vacuum oven at 70 °C for 16 h. It was calcined at 500 °C under pure H2 for 4 h (heating rate of 5 °C / min). The obtained catalyst was recorded as Cat5.

[0066] Example 6

[0067] A Cu-based catalyst for catalytic conversion of carbon dioxide is prepared by the following steps:

[0068] (1) 7.4 mmol of ammonium molybdate tetrahydrate was dissolved in 70 mL of deionized water (DI) and stirred at room temperature for 30 min. Then, 13.6 mmol of fructose was added. The mixed solution was stirred for 0.5 h to obtain a homogeneous solution. The above solution was placed at 110°C to dry overnight. The dried sample was ground into powder in agate. Finally, it was calcined in pure H2 for 15 h at a high temperature of 500°C and a heating rate of 10°C / min to obtain a Mo2C support.

[0069] (2) Disperse 1 g of Mo2C support in 50 mL of ultrapure water and stir at room temperature for 10 min. Then, dissolve copper acetate and cerium acetate in 25 mL of ultrapure water, with the molar ratio of copper salt, cerium salt and Mo2C support being 5:5:50. Next, drop the metal cation salt aqueous solution composed of copper acetate and cerium acetate into the dispersion of Mo2C support; at the same time, add potassium carbonate solution (0.60 mol / L) to adjust the pH of the mixed solution to 10, stir for 15 min, age for 30 min, wash with ultrapure water at room temperature, and then dry in a vacuum oven at 70 °C for 15 h. Calcined at 500 °C under pure H2 for 9 h (heating rate of 5 °C / min). The obtained catalyst is designated as Cat6.

[0070] Comparative Example 1

[0071] A Cu-based catalyst for catalytic conversion of carbon dioxide is prepared by the following steps:

[0072] (1) 5.21 g of cerium nitrate hexahydrate was placed in a beaker and dissolved in 10 mL of pure water. Then, 40 mL of a 15 mol / L NaOH solution was added. After stirring at room temperature for 30 min, the mixture was transferred to a 100 mL reactor and kept in an oven at 180 °C for 24 h. After the reaction, the product was washed with pure water until neutral, filtered, dried overnight, and calcined in air at 400 °C for 4 h to obtain a CeO2 carrier.

[0073] (2) Disperse 1 g of CeO2 support in 50 mL of ultrapure water and stir at room temperature for 10 min. Then dissolve copper nitrate trihydrate in 25 mL of ultrapure water, with the molar ratio of copper salt to CeO2 support being 10:50. Next, a metal cation salt aqueous solution consisting solely of copper nitrate trihydrate was dripped into the dispersion of CeO2 support; at the same time, sodium bicarbonate solution (0.5 mol / L) was added to adjust the pH of the mixed solution to 9, stirred for 30 min, aged for 1 h, washed with ultrapure water at room temperature, then dried in a vacuum oven at 70 °C for 11 h, and calcined at 500 °C under pure H2 for 4 h (heating rate of 5 °C / min). The resulting catalyst was designated Cat7.

[0074] Test Case

[0075] The XRD patterns of the catalysts of each embodiment and each comparative example were observed by X-ray diffractometer, wherein the XRD pattern of Example 3 is as follows: Figure 1 As shown. Figure 1 The XRD diffraction peaks of the Cat 3 catalyst in Example 3 overlap with those of the standard diffraction peaks of Mo2C (PDF#65-8766), indicating the presence of a Mo2C phase in the Cat 3 catalyst. However, the absence of significant Cu, CuO, or CeO2 diffraction peaks suggests that the active metal Cu and nanoparticle CeO2 are highly dispersed on the Mo2C support, forming more catalytically active interfaces.

[0076] The catalysts of each embodiment and comparative example were loaded into a fixed-bed reaction in a quartz tube with an inner diameter of 10 mm, and 100% H2 was introduced. The temperature was raised to 600°C for reduction for 1 hour. In the evaluation of the reverse water gas reaction, an H2 / CO2 gas flow was introduced at a feed ratio of 4:1. The test temperature range was 300-600°C. The product composition was analyzed and detected online using a Gasboard 3100 infrared gas analyzer at 300°C, 350°C, 400°C, 450°C, 500°C, 550°C, and 600°C. The test results are shown in Figure 2. Figure 2 As shown in Table 1. The CO2 conversion rate and CO selectivity are calculated according to the following formula:

[0077]

[0078]

[0079] Where: is the carbon dioxide conversion rate; [CO] is the molar concentration of carbon monoxide; [CH4] is the molar concentration of methane; [CO2] is the molar concentration of carbon dioxide; S CO is the selectivity of the catalyst for carbon monoxide.

[0080] Table 1600℃ catalyst activity test results

[0081]

[0082] As can be seen from Table 1, the catalyst of the present invention is heated at atmospheric pressure and a mass space velocity of 200,000 mL·gcat. -1 ·h -1Under high space velocity conditions, it shows excellent carbon dioxide conversion. In all embodiments, the CO selectivity of the catalyst is close to 100%. Judging from the catalytic activity data of CO2 conversion, the catalysts of each embodiment show relatively good catalytic activity. In sharp contrast, the catalytic activity of the catalyst in Comparative Example 1 is relatively low. This shows that the introduction of Mo2C significantly improves the performance of the catalyst, which may be due to the strong metal-support interaction between Mo2C and Cu and CeO2, which promotes the formation and activation of reactive sites on the catalyst surface and enhances the adsorption and conversion capacity of CO2.

[0083] Combine Figure 2 It can be seen that the Cat 3 catalyst has a high performance under harsh conditions (600℃, mass space velocity GHSV of 200,000mL·gcat -1 ·h -1 ) exhibited excellent performance, achieving a CO conversion of 65.12% and 100% CO selectivity, demonstrating significant potential for industrial application. The Cat 2 catalyst maintained high catalytic activity at a relatively low temperature (400°C), achieving a CO conversion of 32.09% and 100% CO selectivity, effectively reducing energy consumption and equipment requirements.

[0084] Combine Figure 3 The performance analysis of Cat 3 catalyst shows that at 600℃ and mass space velocity GHSV of 200,000mL·gcat -1 ·h -1 Under the harsh reaction conditions of , the catalyst exhibits excellent high-temperature stability. At the initial stage of the reaction, the CO2 conversion rate is as high as 65.12%, which fully proves that the Cat 3 catalyst has the activity of efficiently driving CO2 conversion in the initial stage and can quickly activate the reaction path. As the reaction time increases, the CO2 conversion rate stabilizes at around 50% after 40 hours, indicating that the catalyst system has entered a steady-state activity stage. From an in-depth analysis of the catalytic mechanism, this stability shows that after the initial reaction, the Cat 3 catalyst can maintain stable catalytic performance despite the possible carbon deposition coverage or structural micro-adjustment of the active sites, reflecting that its active sites have the ability to resist deactivation under high temperature and high space velocity conditions.

[0085] In summary, the present invention can provide a Cu-CeO2 / Mo2C catalyst with high catalytic activity. Compared with the prior art, the present invention has significant progress.

[0086] The above description is merely a representative embodiment of the present invention and does not constitute any form of limitation to the present invention. Any technical personnel familiar with the present invention who, without departing from the scope of the technical solution of the present invention, makes some changes or modifications to the embodiments disclosed above using the technical contents disclosed above are equivalent embodiments of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a Cu-based catalyst for catalytic conversion of carbon dioxide, characterized in that: The following steps are involved: S1: preparing a precursor solution for providing a molybdenum source, and mixing the precursor solution with an organic matter, stirring uniformly to obtain a mixture; S2: drying the mixture, and then calcining it at high temperature under a pure hydrogen atmosphere to obtain a Mo2C carrier; S3: dispersing the Mo2C support into pure water, and dropping a metal cation salt aqueous solution providing a copper source and a cerium source, adjusting the pH to alkaline, stirring, aging, and filtering to obtain a precipitate; S4: drying the precipitate in a vacuum, and then calcining the precipitate under a pure hydrogen atmosphere to obtain a Cu-CeO2 / Mo2C catalyst.

2. The method for preparing a Cu-based catalyst for catalytic conversion of carbon dioxide according to claim 1, characterized in that: In step S1, the solute of the precursor solution is any one or more of ammonium molybdate tetrahydrate, sodium molybdate, and molybdenum chloride.

3. The method for preparing a Cu-based catalyst for catalytic conversion of carbon dioxide according to claim 1, characterized in that: In step S1, the organic matter is any one or more of sucrose, glucose, maltose, lactose, fructose, cellobiose, D-xylose, xylitol, erythritol, and sorbitol.

4. The method for preparing a Cu-based catalyst for catalytic conversion of carbon dioxide according to claim 1, characterized in that: In step S1, the molar ratio of the solute in the precursor solution to the organic matter is 1:1-10.

5. The method for preparing a Cu-based catalyst for catalytic conversion of carbon dioxide according to claim 1, characterized in that: In step S1, when stirring is performed, the temperature is 10-30°C and the time is 0.1-5h; in step S2, when drying is performed, the temperature is 50-130°C and the time is 10-48h; in step S2, when high-temperature calcination is performed, the heating rate is 1-10°C / min, the temperature is 400-600°C, and the time is 10-48h.

6. The method for preparing a Cu-based catalyst for catalytic conversion of carbon dioxide according to claim 1, characterized in that: In step S3, the solute of the metal cation salt solution is a mixed salt of a copper salt and a cerium salt, the copper salt is any one or more of copper nitrate trihydrate, copper chloride dihydrate, copper sulfate pentahydrate, and copper acetate, and the cerium salt is any one or more of cerium nitrate hexahydrate, cerium chloride heptahydrate, cerous sulfate, cerium acetate, and ammonium ceric nitrate; the molar ratio of the copper salt, the cerium salt, and the Mo2C carrier is 1:1:50-30:30:

50.

7. The method for preparing a Cu-based catalyst for catalytic conversion of carbon dioxide according to claim 1, characterized in that: In step S3, an alkaline solution with a concentration of 0.1-15 mol / L is used to adjust the pH to 8-10, and the solute of the alkaline solution is any one or more of urea, ammonium carbonate, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, ammonia water, sodium hydroxide, and potassium hydroxide.

8. The method for preparing a Cu-based catalyst for catalytic conversion of carbon dioxide according to claim 1, characterized in that: In step S3, the stirring is performed at a temperature of 10-80° C. and a time of 0.1-2 h; and the aging is performed at a temperature of 10-80° C. and a time of 0.1-2 h.

9. The method for preparing a Cu-based catalyst for catalytic conversion of carbon dioxide according to claim 1, characterized in that: In step S4, during drying, the temperature is 50-100° C. and the time is 4-48 hours; during calcination, the heating rate is 1-10° C. / min, the temperature is 400-800° C. and the time is 1-8 hours.

10. A Cu-based catalyst for catalytic conversion of carbon dioxide, characterized in that: The catalyst is prepared by the method for preparing a Cu-based catalyst for catalytic conversion of carbon dioxide according to any one of claims 1 to 9.

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