Preparation method and application of graphene-wrapped bismuth oxide-loaded copper oxide nanoparticle catalyst

Abstract

The present invention provides a method for preparing and applying a graphene-wrapped bismuth oxide-supported copper oxide nanoparticle catalyst. This method utilizes graphene-wrapped bismuth oxide as a carrier, supported copper oxide nanoparticles as the catalytically active component, a tantalum-hafnium composite oxide as a co-catalyst, and a complex of potassium iodide and sodium bromide as a directed growth agent. The catalyst incorporates graphene-wrapped bismuth oxide as a carrier, increasing its specific surface area and improving its activity and selectivity. Furthermore, the catalyst exhibits excellent heat resistance and stability, high conversion efficiency, and environmental friendliness, making it widely applicable to fields such as the hydrogenation of carbon dioxide to produce methanol.

Description

Technical Field

[0001] The present invention relates to a preparation method and application of a graphene-wrapped bismuth oxide-loaded copper oxide nanoparticle catalyst, belonging to the fields of environmentally friendly catalytic materials and carbon dioxide treatment. The catalyst prepared by the method can improve the carbon dioxide conversion rate and methanol selectivity. Background Art

[0002] With the rapid development of global industry, the consumption of fossil fuel energy such as coal, oil, and natural gas has continued to grow, making natural resources increasingly scarce. In addition, the large-scale burning of fossil fuels has led to an increase in carbon dioxide emissions. The greenhouse effect caused by CO2 emissions has aroused great concern about catastrophic consequences such as climate change, energy crisis and sea level rise. Therefore, it is urgent to reduce carbon dioxide emissions and achieve clean energy regeneration. At present, in order to effectively alleviate the above problems, countries around the world are constantly developing key technologies of CCUS (CO2 capture, utilization and storage), which can effectively control the content of CO2 and make important contributions to achieving carbon neutrality goals. Among them, the catalytic conversion of carbon dioxide into high-value-added products such as methanol, formic acid, hydrocarbons, etc. is the key to achieving efficient resource utilization of carbon dioxide, which has more far-reaching practical significance and greater market prospects.

[0003] Currently, researchers have developed key technologies for CO2 absorption and conversion, including catalytic hydrogenation, thermal catalysis, photocatalysis, electrocatalysis, and photoelectrocatalysis. Considering that fossil energy is produced through natural hydrocarbon hydrogenation, utilizing the catalytic hydrogenation of CO2 to produce high-value-added products such as methanol is particularly beneficial for carbon reduction. However, in catalytic hydrogenation, CO2 is an inert gas with a stable chemical structure, requiring high temperatures to generate sufficient activation energy. Therefore, the catalyst is crucial for CO2 hydrogenation to methanol. The activity, stability, and cost of the catalyst largely determine the methanol yield, purity, and economic viability of CO2 hydrogenation to methanol technology. In recent years, numerous researchers have conducted extensive research on the preparation and modification of CO2 hydrogenation catalysts, some of which have been used in pilot plants and demonstration facilities. Among the various catalysts used in the reaction of carbon dioxide hydrogenation to methanol, Cu-based catalysts are the earliest used and most studied catalysts, mainly Cu / Zn system. Common ones include Cu / ZnO, Cu / ZnO / Al2O3, Cu / ZnO / ZrO2, Cu / ZnO / SiO2 and other catalysts with oxides as carriers.

[0004] Among the existing patents for catalysts for the hydrogenation of carbon dioxide to produce methanol, patent CN202110931675.8 synthesizes defect-rich thin-layer two-dimensional metal sulfide for the hydrogenation of carbon dioxide to produce methanol by adopting a high-temperature and high-pressure solvent thermal coupling reduction method. The rich defects make it have high activity for the hydrogenation of carbon dioxide to produce methanol. Patent CN202111534364.4 uses zinc acetate and hexamethylenetetramine as raw materials, and prepares a Cu / ZnO / ZrO2 catalyst derived from a two-dimensional layered structure coordination polymer by a self-assembly method. The methanol space-time yield of this catalyst is higher than that of the impregnation method and has good stability. Patent CN202010514932.3 prepares a Cu / ZnO catalyst with an ultra-small surface area using graphene oxide with a high specific surface area as a carrier. x The nanoparticle CuZn@UiO-bpy / GO catalyst exhibits high stability and dispersibility, improving methanol selectivity and yield. GO also exhibits strong thermal stability, preventing carbon deposition and catalyst deactivation caused by the high reaction temperatures during CO2 conversion. Therefore, developing catalysts with high activity, selectivity, and stability has become a research priority and has far-reaching implications for CO2 emission reduction. Summary of the Invention

[0005] The purpose of the present invention is to address the current status and problems of carbon dioxide emissions and carbon emission reduction, and to propose a graphene-wrapped bismuth oxide-loaded copper oxide nanoparticle catalyst. Another purpose of the present invention is to provide a method for preparing the above-mentioned catalyst to improve the conversion rate of carbon dioxide and the selectivity of methanol.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] The technical solution of the present invention is as follows: the present invention adopts graphene-wrapped bismuth oxide as a carrier, uses potassium iodide and sodium bromide as directional growth agents for graphene, so that the graphene grows into a graphene form with a large specific surface area, high structural stability, and high chemical stability and activity; supports copper oxide nanoparticles as catalytically active components, which have good catalytic activity and can increase the reaction rate; and selects tantalum-hafnium composite oxide as a co-catalyst, which can increase the dispersion of copper oxide, control the particle size of copper oxide, and inhibit sintering, so that the copper oxide has better catalytic performance and stability.

[0008] The specific technical solutions of the present invention are:

[0009] A graphene-wrapped bismuth oxide-loaded copper oxide nanoparticle catalyst uses graphene-wrapped bismuth oxide as a carrier, loaded copper oxide nanoparticles as a catalytically active component, a tantalum-hafnium composite oxide as a co-catalyst, and a complex of potassium iodide and sodium bromide as a directional growth agent. Based on the mass of the carrier, the mass percentage of the catalytically active component, copper oxide, is 2% to 10%, and the mass percentage of the co-catalyst, tantalum-hafnium composite, is 2% to 8%.

[0010] In the technical solution of the present invention, the mass ratio of bismuth oxide to graphene in the carrier is 2-6:94-98; the mass ratio of tantalum pentoxide to hafnium oxide in the promoter is 1:(0.2-0.5).

[0011] A method for preparing the above catalyst comprises the following steps:

[0012] (1) Preparation of catalyst carrier

[0013] Weigh a bismuth nitrate solution, add a sodium hydroxide aqueous solution dropwise at 80-90° C., mix and stir to react to obtain a bismuth oxide hydrate, wash, filter and dry, and then heat in an oven at 80-90° C. for 10-30 minutes to obtain bismuth oxide; add deionized water, potassium iodide and sodium bromide to the bismuth oxide, mix evenly, stir, and filter and dry; then place the obtained bismuth oxide modified with potassium iodide and sodium bromide in a tube furnace, introduce toluene and water vapor to react, and obtain a graphene-wrapped bismuth oxide carrier;

[0014] (2) Preparation of active component precursor solution

[0015] Adding copper salt to deionized water and stirring evenly to obtain an active component precursor solution;

[0016] (3) Preparation of co-catalyst precursor ion solution

[0017] Adding tantalum salt and hafnium salt into deionized water and stirring uniformly to obtain a co-catalyst precursor solution;

[0018] (4) Preparation of catalyst

[0019] The active component precursor ion solution prepared in step (2) and the co-catalyst precursor ion solution prepared in step (3) are mixed evenly, and added together to the graphene-wrapped bismuth oxide carrier prepared in step (1), and transferred to a hydrothermal reactor for hydrothermal reaction. The mixture obtained after the reaction is placed in a blast drying oven for heat preservation and drying, and then placed in a muffle furnace and calcined in an air atmosphere to obtain a graphene-wrapped bismuth oxide-loaded copper oxide catalyst.

[0020] In the above preparation method: the concentration of the bismuth nitrate solution described in step (1) is 0.1-0.3 mol / L, the concentration of sodium hydroxide is 0.1-0.3 mol / L, and the mass ratio of the bismuth nitrate and sodium hydroxide solution described in step (1) is (3-5):1.

[0021] The above preparation method is characterized in that: the mass ratio of bismuth oxide, potassium iodide and sodium bromide described in step (1) is 1:(1-3):(1-3); the stirring time is 20-40 minutes, the drying temperature is 60-80°C, and the drying time is 6-12 hours; the heating temperature of the tube furnace described in step (1) is 300-450°C, and the time of placing in the tube furnace is 6-8 hours.

[0022] The above preparation method is characterized in that the volume ratio or mass ratio of toluene and water vapor in step (1) is 1:(2-4).

[0023] In the above preparation method: the temperature of the hydrothermal reaction in step (4) is 120-180° C., and the time of the hydrothermal reaction is 8-12 h.

[0024] In the above preparation method: in step (4), the drying temperature is 60-100° C., and the drying time is 4-8 hours; the roasting temperature is 500-600° C., and the roasting time is 2-4 hours.

[0025] In the technical solution of the present invention, the graphene-wrapped bismuth oxide-supported copper oxide nanoparticle catalyst is used in the production of methanol by hydrogenation of carbon dioxide. Furthermore, the catalytic temperature is 80-180°C.

[0026] The catalytic reaction conditions and results of the present invention are as follows: a 2 mL catalyst sample is placed in a catalyst performance evaluation reaction device. The inner diameter of the quartz tube in the evaluation reaction device is 10 mm, and simulated gas is introduced for activity evaluation. The simulated gas composition is: 0.03% to 0.04% CO2, 0.12% to 0.16% H2, 2% to 6% H2O, and 93.8% to 98.7% N2 as a carrier gas. The catalytic reaction test temperature range is 80 to 180°C, the heating rate is 5 to 15°C / min, and the reaction volume space velocity is 8000 to 12000 h -1 The test results show that the carbon dioxide conversion efficiency exceeds 15% and the methanol selectivity is greater than 90% within 90-180°C.

[0027] Beneficial effects:

[0028] The present invention adopts a catalyst carrier prepared by a reforming hydrogen production method, which has a simple preparation process, good selectivity, and no secondary pollution to the environment. The catalyst of the present invention has high carbon dioxide conversion efficiency and methanol selectivity, a low active temperature, and has a high catalytic efficiency within 90 to 180 ° C. Compared with the prior art, the active temperature range of the catalyst system is 90 to 180 ° C. Compared with the catalytic temperature of 200 to 400 ° C of the existing copper-based catalyst, low-temperature catalysis is more suitable for the treatment of carbon dioxide in actual production, reducing economic costs. In addition, the prepared catalyst is loaded with active components inside and outside, and has a co-catalyst, which greatly improves the conversion rate of carbon dioxide and the selectivity of methanol. In addition, the catalyst component is environmentally friendly, can effectively reduce the investment cost and operating cost of industries such as carbon emission reduction and methanol production, and has a strong application and promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The performance diagram of the catalysts prepared in Examples 1 to 3.

[0030] Figure 2 The performance diagram of the catalysts prepared in Comparative Examples 1 to 4 is shown. DETAILED DESCRIPTION

[0031] The present invention will be further described below with reference to the following examples, but the scope of protection of the present invention is not limited thereto: Example 1

[0032] (1) Preparation of catalyst carrier

[0033] First, take 100ml of 0.1mol / L bismuth nitrate solution, add 300ml of 0.1mol / L CO2-free sodium hydroxide aqueous solution to it at 80°C, so that the mass ratio of bismuth nitrate and sodium hydroxide solution is 3:1, mix to obtain bismuth oxide hydrate, continue stirring, dehydrate, wash, filter and dry, and heat in an oven for 10 minutes to obtain bismuth oxide. Weigh 10g of the prepared bismuth oxide, add 20g of deionized water, 10g of potassium iodide and 10g of sodium bromide, mix well, stir for 20min, use the impregnation loading method to modify potassium iodide and sodium bromide on the surface of bismuth oxide, and dry at 60°C. The modified bismuth oxide is then placed in a 300°C tube furnace, and toluene and water vapor (mass ratio of 1:2) are introduced. After reacting for 6h, a graphene-wrapped bismuth oxide carrier is obtained;

[0034] (2) Preparation of active component precursor solution

[0035] Weigh 17.0886 g of copper chloride, add 40 g of deionized water, and stir at room temperature for 30 minutes to obtain an active component precursor solution; wherein the mass percentage of copper oxide in the active component is 2%;

[0036] (3) Preparation of co-catalyst precursor ion solution

[0037] Weigh 8.8919 g of potassium fluorotantalate and 3.0434 g of hafnium tetrachloride, add 25 g of deionized water, and stir at room temperature for 15 minutes to obtain a co-catalyst precursor solution; wherein the mass percentage of the co-catalyst is 8%, and the mass ratio of tantalum pentoxide to hafnium oxide is 1:0.2;

[0038] (4) Preparation of catalyst

[0039] The active component precursor ion solution prepared in step (2) and the co-catalyst precursor ion solution prepared in step (3) are mixed, and the mixture is added together to the graphene-wrapped bismuth oxide carrier prepared in step (1), and the mixture is transferred to a hydrothermal reactor. After the mixture is hydrothermally reacted at 130° C. for 8 h, the mixture is taken out and cooled to room temperature, placed in a forced air drying oven, dried at 60° C. for 4 h, and then placed in a muffle furnace at 500° C., and calcined in an air atmosphere for 2 h to obtain a graphene-wrapped bismuth oxide-supported copper oxide catalyst;

[0040] (5) Catalytic activity test

[0041] A 2mL catalyst sample was placed in a 10mm inner diameter quartz tube in the catalyst performance evaluation reactor. Simulated gas was introduced for activity evaluation. The simulated gas composition consisted of 0.03% CO2, 0.12% H2, 2% H2O, and 97.85% N2 as a carrier gas. The catalytic reaction was tested at a temperature range of 80-180°C, a heating rate of 5°C / min, and a reaction volume space velocity of 8000 h / min. -1 The test results show that the carbon dioxide conversion efficiency exceeds 15% and the methanol selectivity is greater than 90% within 90-180°C.

[0042] Example 2

[0043] (1) Preparation of catalyst carrier

[0044] First, take 295ml of 0.3mol / L bismuth nitrate solution, add 150ml of 0.3mol / L CO2-free sodium hydroxide aqueous solution to it at 90°C, so that the mass ratio of bismuth nitrate and sodium hydroxide solution is 5:1, mix, and obtain bismuth oxide hydrate. Continue stirring, dehydrate, wash, filter, and dry, and heat in an oven for 30min to obtain bismuth oxide. Weigh 10g of the prepared bismuth oxide, add 25g of deionized water, 10g of potassium iodide, and 11g of sodium bromide, mix evenly, stir for 40min, use the impregnation loading method to modify potassium iodide and sodium bromide on the surface of bismuth oxide, and dry at 80°C. The modified bismuth oxide is then placed in a 450°C tube furnace, and toluene and water vapor (mass ratio of 1:4) are introduced. After reacting for 8h, a graphene-wrapped bismuth oxide carrier is obtained.

[0045] (2) Preparation of active component precursor solution

[0046] Weigh 85.443 g of copper chloride, add 200 g of deionized water, and stir at room temperature for 30 minutes to obtain an active component precursor solution; wherein the mass percentage of copper oxide in the active component is 10%;

[0047] (3) Preparation of co-catalyst precursor ion solution

[0048] Weigh 35.5676 g of potassium fluorotantalate and 12.1736 g of hafnium tetrachloride, add 120 g of deionized water, and stir at room temperature for 15 minutes to obtain a co-catalyst precursor solution; wherein the mass percentage of the co-catalyst is 8%, and the mass ratio of tantalum pentoxide to hafnium oxide is 1:0.5;

[0049] (4) Preparation of catalyst

[0050] The active component precursor ion solution prepared in step (2) and the co-catalyst precursor ion solution prepared in step (3) are mixed, and the mixture is added together to the graphene-wrapped bismuth oxide carrier prepared in step (1), and the mixture is transferred to a hydrothermal reactor. After the mixture is hydrothermally reacted at 180° C. for 12 h, the mixture is taken out and cooled to room temperature, placed in a forced air drying oven, dried at 100° C. for 8 h, and then placed in a muffle furnace at 600° C., and calcined in an air atmosphere for 4 h to obtain a graphene-wrapped bismuth oxide-supported copper oxide catalyst;

[0051] (5) Catalytic activity test

[0052] A 2mL catalyst sample was placed in a 10mm inner diameter quartz tube in a catalyst performance evaluation reactor. Simulated gas was introduced for activity evaluation. The simulated gas composition consisted of 0.04% CO2, 0.16% H2, 6% H2O, and 93.8% N2 as a carrier gas. The catalytic reaction was tested at a temperature range of 80-180°C, a heating rate of 15°C / min, and a reaction volume space velocity of 12,000 h / min. -1 The test results show that the carbon dioxide conversion efficiency exceeds 15% and the methanol selectivity is greater than 90% within 90-180°C.

[0053] Example 3

[0054] (1) Preparation of catalyst carrier

[0055] First, take 247ml of 0.2mol / L bismuth nitrate solution, add 100ml of 0.2mol / L CO2-free sodium hydroxide aqueous solution to it at 85°C, so that the mass ratio of bismuth nitrate and sodium hydroxide solution is 4:1, mix, and obtain bismuth oxide hydrate. Continue stirring, dehydrate, wash, filter, and dry, and heat in an oven for 20min to obtain bismuth oxide. Weigh 10g of the prepared bismuth oxide, add 30g of deionized water, 10g of potassium iodide, and 12g of sodium bromide, mix evenly, stir for 30min, use the impregnation loading method to modify potassium iodide and sodium bromide on the surface of bismuth oxide, and dry at 70°C. The modified bismuth oxide is then placed in a 375°C tube furnace, and toluene and water vapor (mass ratio of 1:3) are introduced. After reacting for 7h, a graphene-wrapped bismuth oxide carrier is obtained.

[0056] (2) Preparation of active component precursor solution

[0057] Weigh 51.2658 g of copper chloride, add 150 g of deionized water, and stir at room temperature for 30 minutes to obtain an active component precursor solution; wherein the mass percentage of copper oxide in the active component is 6%;

[0058] (3) Preparation of co-catalyst precursor ion solution

[0059] Weigh 22.2298 g of potassium fluorotantalate and 7.6085 g of hafnium tetrachloride, add 90 g of deionized water, and stir at room temperature for 15 minutes to obtain a co-catalyst precursor solution; wherein the mass percentage of the co-catalyst is 5%, and the mass ratio of tantalum pentoxide to hafnium oxide is 1:0.35;

[0060] (4) Preparation of catalyst

[0061] The active component precursor ion solution prepared in step (2) and the co-catalyst precursor ion solution prepared in step (3) are mixed, and the mixture is added together to the graphene-wrapped bismuth oxide carrier prepared in step (1), and the mixture is transferred to a hydrothermal reactor. After the hydrothermal reaction at 155° C. for 10 h, the mixture is taken out and cooled to room temperature, placed in a forced air drying oven, dried at 90° C. for 6 h, and then placed in a muffle furnace at 550° C. and calcined in an air atmosphere for 3 h to obtain a graphene-wrapped bismuth oxide-supported copper oxide catalyst;

[0062] (5) Catalytic activity test

[0063] A 2mL catalyst sample was placed in a 10mm inner diameter quartz tube in the catalyst performance evaluation reactor. Simulated gas was introduced for activity evaluation. The simulated gas composition consisted of 0.035% CO2, 0.14% H2, 4% H2O, and 95.825% N2 as a carrier gas. The catalytic reaction was tested at a temperature range of 80-180°C, a heating rate of 10°C / min, and a reaction volume space velocity of 20,000 h. -1 The test results show that the carbon dioxide conversion efficiency exceeds 15% and the methanol selectivity is greater than 90% within 90-180°C.

[0064] Comparative Example 1

[0065] (1) Preparation of catalyst carrier

[0066] Except that potassium iodide was not used for modification during the preparation of the catalyst support, other conditions were the same as those in Example 1;

[0067] (2) Catalyst activity test

[0068] A 2mL catalyst sample was placed in a 10mm inner diameter quartz tube in the catalyst performance evaluation reactor. Simulated gas was introduced for activity evaluation. The simulated gas composition consisted of 0.03% CO2, 0.12% H2, 2% H2O, and 97.85% N2 as a carrier gas. The catalytic reaction was tested at a temperature range of 80-180°C, a heating rate of 5°C / min, and a reaction volume space velocity of 8000 h / min. -1 The test results show that the carbon dioxide conversion efficiency is less than 10% and the methanol selectivity is less than 70% within 90-180°C.

[0069] (3) Contrast effect

[0070] Compared with Example 1, potassium iodide was not used for modification during the preparation of the catalyst support, and only very little graphene oxide was generated on the surface of the catalyst support, resulting in a significant decrease in catalytic efficiency.

[0071] Comparative Example 2

[0072] (1) Preparation of catalyst carrier

[0073] Except that sodium bromide was not used for modification during the preparation of the catalyst support, other conditions were the same as those in Example 1;

[0074] (2) Catalyst activity test

[0075] A 2mL catalyst sample was placed in a 10mm inner diameter quartz tube in the catalyst performance evaluation reactor. Simulated gas was introduced for activity evaluation. The simulated gas composition consisted of 0.03% CO2, 0.12% H2, 2% H2O, and 97.85% N2 as a carrier gas. The catalytic reaction was tested at a temperature range of 80-180°C, a heating rate of 5°C / min, and a reaction volume space velocity of 8000 h / min. -1 The test results show that the carbon dioxide conversion efficiency is less than 10% and the methanol selectivity is less than 70% within 90-180°C.

[0076] (3) Contrast effect

[0077] Compared with Example 1, sodium bromide was not used for modification during the preparation of the catalyst support, and only very little graphene oxide was generated on the surface of the catalyst support, resulting in a significant decrease in catalytic efficiency.

[0078] Comparative Example 3

[0079] (1) Preparation of catalyst carrier

[0080] Except that potassium iodide and sodium bromide were not used for modification during the preparation of the catalyst support, other conditions were the same as those in Example 1;

[0081] (2) Catalyst activity test

[0082] A 2mL catalyst sample was placed in a 10mm inner diameter quartz tube in the catalyst performance evaluation reactor. Simulated gas was introduced for activity evaluation. The simulated gas composition consisted of 0.03% CO2, 0.12% H2, 2% H2O, and 97.85% N2 as a carrier gas. The catalytic reaction was tested at a temperature range of 80-180°C, a heating rate of 5°C / min, and a reaction volume space velocity of 8000 h / min. -1 The test results show that the carbon dioxide conversion efficiency is less than 10% and the methanol selectivity is less than 70% within 90-180°C.

[0083] (3) Contrast effect

[0084] Compared with Example 1, potassium iodide and sodium bromide were not used for modification during the preparation of the catalyst support, graphene oxide could not be generated on the surface of the catalyst support, and the catalytic efficiency decreased significantly.

[0085] Comparative Example 4

[0086] (1) Preparation of co-catalyst precursor ion solution

[0087] Except that hafnium tetrachloride is not added when preparing the co-catalyst precursor ion solution, other conditions are the same as those in Example 3;

[0088] (2) Catalyst activity test

[0089] A 2mL catalyst sample was placed in a 10mm inner diameter quartz tube in the catalyst performance evaluation reactor. Simulated gas was introduced for activity evaluation. The simulated gas composition consisted of 0.035% CO2, 0.14% H2, 4% H2O, and 95.825% N2 as a carrier gas. The catalytic reaction was tested at a temperature range of 80-180°C, a heating rate of 10°C / min, and a reaction volume space velocity of 20,000 h. -1 The test results show that the carbon dioxide conversion efficiency is less than 10% and the methanol selectivity is less than 80% within 90-180°C.

[0090] (3) Contrast effect

[0091] Compared with Example 3, hafnium tetrachloride was not added when the co-catalyst precursor ion solution was prepared, and the catalytic efficiency was significantly reduced.

Claims

1. A method for preparing a graphene-coated bismuth oxide-supported copper oxide nanoparticle catalyst, characterized in that: The catalyst uses graphene-wrapped bismuth oxide as a carrier, loaded copper oxide nanoparticles as a catalytically active component, and a tantalum-hafnium composite oxide as a co-catalyst. Based on the mass of the carrier, the mass percentage of the catalytically active component, copper oxide, is 2% to 10%, and the mass percentage of the co-catalyst, tantalum-hafnium composite, is 2% to 8%. The preparation method of the catalyst is as follows: (1) Preparation of catalyst carrier Weigh a bismuth nitrate solution, add a sodium hydroxide aqueous solution dropwise at 80-90°C, mix and stir to react to obtain a bismuth oxide hydrate, wash, filter and dry, and then place in an oven at 80-90°C and heat for 10-30 minutes to obtain bismuth oxide; add deionized water, potassium iodide and sodium bromide to the bismuth oxide, mix evenly, stir, filter and dry; then place the obtained bismuth oxide modified with potassium iodide and sodium bromide in a tube furnace, introduce toluene and water vapor to react, and obtain a graphene-wrapped bismuth oxide carrier; the complex of potassium iodide and sodium bromide is a directional growth agent, (2) Preparation of active component precursor solution Adding copper salt to deionized water and stirring evenly to obtain an active component precursor solution; (3) Preparation of co-catalyst precursor ion solution Adding tantalum salt and hafnium salt into deionized water and stirring uniformly to obtain a co-catalyst precursor solution; (4) Preparation of catalyst The active component precursor ion solution prepared in step (2) and the co-catalyst precursor ion solution prepared in step (3) are mixed evenly, and added together to the graphene-wrapped bismuth oxide carrier prepared in step (1), and transferred to a hydrothermal reactor for hydrothermal reaction. The mixture obtained after the reaction is placed in a blast drying oven for heat preservation and drying, and then placed in a muffle furnace and calcined in an air atmosphere to obtain a graphene-wrapped bismuth oxide-loaded copper oxide catalyst.

2. The preparation method according to claim 1, wherein: The mass ratio of bismuth oxide to graphene in the carrier is 2~6:94~98; the mass ratio of tantalum pentoxide to hafnium oxide in the co-catalyst is 1:(0.2~0.5).

3. The preparation method according to claim 1, wherein: The concentration of the bismuth nitrate solution described in step (1) is 0.1-0.3 mol / L, and the concentration of sodium hydroxide is 0.1-0.3 mol / L.

4. The preparation method according to claim 1, wherein: The mass ratio of bismuth oxide, potassium iodide and sodium bromide in step (1) is 1:(1-3):(1-3); the heating temperature of the tube furnace in step (1) is 300-450° C., and the time of being placed in the tube furnace is 6-8 hours.

5. The preparation method according to claim 1, wherein: The volume ratio or mass ratio of toluene and water vapor described in step (1) is 1:(2-4).

6. The preparation method according to claim 1, wherein: The temperature of the hydrothermal reaction in step (4) is 120-180° C., and the time of the hydrothermal reaction is 8-12 hours.

7. The preparation method according to claim 1, wherein: In step (4), the drying temperature is 60-100° C., and the drying time is 4-8 hours; the roasting temperature is 500-600° C., and the roasting time is 2-4 hours.

8. Use of the graphene-wrapped bismuth oxide-supported copper oxide nanoparticle catalyst prepared by the preparation method according to claim 1 in preparing methanol by hydrogenation of carbon dioxide.

9. The use according to claim 8, characterized in that The catalytic temperature is 80~180℃.

Images