Carbon dioxide hydrogenation catalyst, preparation method and application thereof

Abstract

The application provides a carbon dioxide hydrogenation catalyst and a preparation method and application thereof, and relates to the technical field of catalyst preparation.The catalyst comprises a carrier and an active component, the carrier has a nanorod structure, the active component Mo2C is loaded on the outer surface of the carrier, and forms a catalytic reaction layer with the outer surface of the carrier to perform synergistic regulation and improve the ethanol selectivity of the catalyst.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of catalyst preparation, in particular to a carbon dioxide hydrogenation catalyst and a preparation method and application thereof. BACKGROUND

[0002] Due to industrial and human activities, the emission of CO2 after the combustion of fossil fuels is increasing year by year, which has brought changes to the global climate and gradually attracted people's attention. CO2 is a rich and sustainable carbon resource, and its utilization can not only reduce CO2 emissions, but also convert CO2 into valuable chemical products or energy. Therefore, the utilization of CO2 has important strategic significance.

[0003] At present, CO2 hydrogenation is mainly used for the synthesis of methanol, such as Chinese patents CN111530458A and CN106861689A. Compared with the synthesis of methanol, the synthesis of low-toxicity ethanol is a better choice. Ethanol is not only an important basic chemical raw material, but also an excellent liquid fuel and gasoline additive, and the transportation process is simpler and the stability is better.

[0004] Therefore, the technology of using green hydrogen to catalytically hydrogenate CO2 to ethanol has attracted widespread attention, and the ethanol selectivity of the catalyst for the direct hydrogenation of CO2 / CO to ethanol is still not ideal. Chinese patent CN111185209A discloses a carbonized molybdenum supported nickel-based catalyst and its application in the preparation of ethanol by hydrogenation of carbon dioxide. The technology uses NiMoO x as a precursor to prepare a Ni / Mo2C catalyst for ethanol synthesis, and the ethanol selectivity is low.

[0005] In summary, it is of great application significance to develop a hydrogenation catalyst with high ethanol selectivity. SUMMARY

[0006] In view of the low ethanol selectivity of the current CO2 hydrogenation catalyst for ethanol, the present application provides a catalyst Mo2C / CeO2 with a nanorod carrier structure to improve the ethanol selectivity of the carbon dioxide hydrogenation catalyst during the reaction process.

[0007] One of the purposes of the present application is to provide a carbon dioxide hydrogenation catalyst.

[0008] The second purpose of the present application is to provide a preparation method of the carbon dioxide hydrogenation catalyst.

[0009] The third purpose of the present application is to provide an application of the carbon dioxide hydrogenation catalyst.

[0010] In order to achieve the above-mentioned purposes of the present application, the following technical solutions are adopted:

[0011] In a first aspect, the present application provides a carbon dioxide hydrogenation catalyst, comprising a CeO2 nanorod carrier and an active component Mo2C loaded on the outer surface of the carrier.

[0012] The loading amount of the active component Mo2C is 3.5wt%-30.5wt% based on the mass of the CeO2 nanorod carrier.

[0013] In some embodiments, the diameter of the CeO2 nanorod carrier is 8-12nm.

[0014] The catalyst of the present application comprises a carrier and an active component, the carrier has a nanorod structure, the active component Mo2C is loaded on the outer surface of the carrier and forms a catalytic reaction layer with the outer surface of the carrier for synergistic regulation.

[0015] In a second aspect, the present application provides a preparation method of the above-mentioned carbon dioxide hydrogenation catalyst, comprising the following steps:

[0016] S1, providing a CeO2 nanorod carrier;

[0017] S2, loading a molybdenum salt on the CeO2 nanorod carrier, and then drying in air to obtain MoO3 / CeO2, the loading amount of MoO3 is 5wt%-30wt% based on the total mass of CeO2 and MoO3;

[0018] S3, reducing and carbonizing MoO3 / CeO2 to obtain a carbon dioxide hydrogenation catalyst Mo2C / CeO2.

[0019] Step S1:

[0020] In some embodiments, the preparation method of the CeO2 nanorod carrier comprises the following steps:

[0021] The cerium salt is dissolved in deionized water to form a cerium precursor aqueous solution, and the solution is magnetically stirred. A strong alkali aqueous solution is added dropwise into the cerium precursor aqueous solution to precipitate, and a mixed suspension is obtained. The mixed suspension is placed in a polytetrafluoroethylene kettle with a stainless steel autoclave for hydrothermal treatment. The precipitate is collected, separated, washed with deionized water and ethanol several times, and then dried in a vacuum oven. The dried powder is calcined in air to obtain the CeO2 nanorod carrier.

[0022] Preferably, the cerium salt is at least one selected from Ce(NO3)3·6H2O, (CH3CO2)3Ce·6H2O and CeCl3·7H2O;

[0023] Preferably, the mass-volume concentration of the cerium precursor aqueous solution is 0.2-0.5g / ml;

[0024] Preferably, the strong alkali aqueous solution is at least one selected from the group consisting of NaOH aqueous solution and KOH aqueous solution;

[0025] Preferably, the molar concentration of the strong alkali aqueous solution is 10-20 mol / L;

[0026] Preferably, the volume ratio of the cerium precursor aqueous solution and the strong alkali aqueous solution is 1:4-6;

[0027] Preferably, the hydrothermal treatment temperature is 100-150℃, and the time is 5-24h;

[0028] Preferably, the calcination temperature is 300-600℃, and the time is 1-4h.

[0029] Step S2:

[0030] The molybdenum salt can be loaded on the CeO2 nanorod carrier by impregnation method, sol-gel method, etc.

[0031] In some embodiments, the molybdenum salt is at least one selected from the group consisting of molybdic acid, paramolybdic acid, molybdate and paramolybdate, and is preferably ammonium molybdate.

[0032] Method one, sol-gel method: dissolve the molybdenum salt in deionized water to form a molybdenum salt aqueous solution, add citric acid, cook in a water bath to make it present as sol, then put the CeO2 nanorod carrier in the sol, and the loading amount of MoO3 is 5wt%-30wt% based on the total mass of the CeO2 nanorod carrier and MoO3.

[0033] Preferably, the molar ratio of citric acid and Mo 3+ is 1-1.1:1;

[0034] Preferably, the water bath temperature is 60-100℃, and is preferably 80℃.

[0035] Method two, impregnation method: dissolve the molybdenum salt in deionized water to form a molybdenum salt aqueous solution, put the CeO2 nanorod carrier into the molybdenum salt aqueous solution for equal volume impregnation, and the loading amount of MoO3 is 5wt%-30wt% based on the total mass of the CeO2 nanorod carrier and MoO3.

[0036] Step S3:

[0037] In some embodiments, the reducing includes: passing hydrogen, and heating to 300-400℃;

[0038] In some embodiments, the heating and carbonizing includes: passing carbonizing gas, heating to 700-800℃ at a heating rate of 2-5℃ / min and maintaining for 2-4h;

[0039] Preferably, the carbonization gas comprises methane and hydrogen, the volume content of methane is 10-20%, and the volume content of hydrogen is 80-90%.

[0040] In a third aspect, the present application provides a use of the above-mentioned carbon dioxide hydrogenation catalyst in the preparation of ethanol by carbon dioxide hydrogenation.

[0041] Preferably, the reaction conditions of the carbon dioxide hydrogenation catalyst are as follows: the reaction temperature is 200-400 ℃, the reaction pressure is 2-8 MPa, the volume space velocity is 2000-6000 h-1, and the volume ratio of hydrogen to carbon dioxide is 4:1-1:1. -1

[0042] Technical effects:

[0043] The carbon dioxide hydrogenation catalyst of the present application has a special CeO2 nanorod structure, the diameter is 8-12 nm, the active component Mo2C is loaded on the outer surface of the carrier, and forms a catalytic reaction layer with the outer surface of the carrier. MoO3 / CeO2 produces strong synergistic effect, and the H2 reduction peak of CeO2 nanorod and MoO3 appears between 585 ℃ and 590 ℃. After carbonization of the Mo2C / CeO2 carbon dioxide hydrogenation catalyst, the activated CO2 of CeO2 and the activated H2 of molybdenum carbide synergistically react to improve the ethanol selectivity of the catalyst.

[0044] The present application has been described in detail above, but the above-mentioned embodiments are only illustrative in nature and are not intended to limit the present application. In addition, this document is not limited by any theory described in the foregoing prior art or summary or in the following examples. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 H2-TPR spectrum of the MoO3 / CeO2 catalyst prepared in Example 1. DETAILED DESCRIPTION

[0046] The present application will be further described below in conjunction with examples, and it should be noted that the following examples are provided only for illustrative purposes and do not constitute a limitation on the scope of protection required by the present application.

[0047] Unless otherwise specified, the raw materials, reagents, methods, etc. used in the examples are conventional raw materials, reagents, methods in the art.

[0048] Example 1

[0049] (1) Dissolve 26.4 g of Ce(NO3)3·6H2O in 100 ml of deionized water, and magnetically stir to form a cerium precursor solution A. Take 252.0 g of NaOH and dissolve in 400 ml of deionized water to form solution B, and drop solution B into solution A. ​

[0050] (2) The mixture of A and B was placed in a polytetrafluoroethylene autoclave equipped with a stainless steel autoclave and subjected to hydrothermal treatment at 100°C for 24 hours. After hydrothermal treatment, the precipitate was separated, washed several times with deionized water and ethanol, and then dried in a vacuum oven at 60°C for 12 hours. The dried powder was calcined in a muffle furnace at 500°C for 2 hours to form CeO2 nanorod carriers.

[0051] (3) The sol-gel method was used to mix 1.22g of (NH4)6Mo7O 24 • Dissolve 4H2O in 10 ml of deionized water, add 1.4 g of citric acid, add 9 g of CeO2 nanorods prepared in (2), stir at 80 °C, and load the molybdenum salt solution onto the CeO2 nanorod support. Dry the prepared precursor in an oven. The loading of MoO3 relative to MoO3 / CeO2 is 10 wt%, and the loading of MoO3 relative to CeO2 is 11.1 wt%.

[0052] (4) After drying, the catalyst was reduced and carbonized by heating in a reaction tube. Hydrogen gas was introduced into the apparatus and the temperature was raised to 300°C. Starting at 300°C, carbonizing gas (10% methane, 90% hydrogen) was introduced, and the temperature was raised to 700°C at a rate of 2°C / min and maintained for 3 hours to complete carbonization, preparing Mo2C / CeO2. The loading of Mo2C relative to CeO2 was 7.86 wt%. Its H2-TPR spectrum is shown below. Figure 1 As shown, MoO3 / CeO2 exhibits a strong synergistic effect, with H2 reduction peaks appearing for CeO2 nanorods and MoO3 between 585℃ and 590℃.

[0053] Example 2

[0054] (1) Dissolve 26.4g Ce(NO3)3·6H2O in 100ml of deionized water and stir magnetically to form cerium precursor solution A. Dissolve 252.0g NaOH in 400ml of deionized water to prepare solution B, and add solution B dropwise to solution A.

[0055] (2) The mixture of A and B was placed in a polytetrafluoroethylene autoclave equipped with a stainless steel autoclave and subjected to hydrothermal treatment at 100°C for 24 hours. After hydrothermal treatment, the precipitate was separated, washed several times with deionized water and ethanol, and then dried in a vacuum oven at 60°C for 12 hours. The dried powder was calcined in a muffle furnace at 500°C for 2 hours to form CeO2 nanorod carriers.

[0056] (3) Add 2.44g of (NH4)6Mo7O 24·4H2O was dissolved in 4 ml of deionized water, and 8 g of CeO2 nanorods prepared in (2) were added. The CeO2 nanorods were then loaded onto the CeO2 nanorod support using an impregnation method. The prepared precursor was dried in stagnant air. The loading of MoO3 relative to MoO3 / CeO2 was 20 wt%, and the loading of MoO3 relative to CeO2 was 25 wt%.

[0057] (4) After drying, the catalyst was reduced in a reaction tube and then carbonized by heating. Hydrogen was introduced into the apparatus and the temperature was raised to 300°C. Starting at 300°C, carbonizing gas (10% methane and 90% hydrogen) was introduced and the temperature was raised to 700°C at a rate of 2°C / min and maintained for 3 hours to complete the carbonization and prepare Mo2C / CeO2. The loading of Mo2C relative to CeO2 was 17.7 wt%.

[0058] Example 3

[0059] (1) Dissolve 26.4g Ce(NO3)3·6H2O in 100ml of deionized water and stir magnetically to form cerium precursor solution A. Dissolve 252.0g NaOH in 400ml of deionized water to prepare solution B, and add solution B dropwise to solution A.

[0060] (2) The mixture of A and B was placed in a polytetrafluoroethylene autoclave equipped with a stainless steel autoclave and subjected to hydrothermal treatment at 100°C for 24 hours. After hydrothermal treatment, the precipitate was separated, washed several times with deionized water and ethanol, and then dried in a vacuum oven at 60°C for 12 hours. The dried powder was calcined in a muffle furnace at 500°C for 2 hours to form CeO2 nanorod carriers.

[0061] (3) Add 0.61g of (NH4)6Mo7O 24 • Dissolve 4H2O in 4 ml of deionized water, add 9.5 g of CeO2 nanorods prepared in (2), and load them onto the CeO2 nanorod support using an impregnation method. Dry the prepared precursor in stagnant air. The loading of MoO3 relative to MoO3 / CeO2 is 5 wt%, and the loading of MoO3 relative to CeO2 is 5.26 wt%.

[0062] (4) After drying, the catalyst was reduced in a reaction tube and then carbonized by heating. Hydrogen was introduced into the apparatus and the temperature was raised to 300°C. Starting at 300°C, carbonizing gas (10% methane and 90% hydrogen) was introduced and the temperature was raised to 700°C at a rate of 2°C / min and maintained for 3 hours to complete carbonization and prepare Mo2C / CeO2. The loading of Mo2C relative to CeO2 was 3.72 wt%.

[0063] Example 4

[0064] (1) Dissolve 26.4g Ce(NO3)3·6H2O in 100ml of deionized water and stir magnetically to form cerium precursor solution A. Dissolve 252.0g NaOH in 400ml of deionized water to prepare solution B, and add solution B dropwise to solution A.

[0065] (2) The mixture of A and B was placed in a polytetrafluoroethylene autoclave equipped with a stainless steel autoclave and subjected to hydrothermal treatment at 100°C for 24 hours. After hydrothermal treatment, the precipitate was separated, washed several times with deionized water and ethanol, and then dried in a vacuum oven at 60°C for 12 hours. The dried powder was calcined in a muffle furnace at 500°C for 2 hours to form CeO2 nanorod carriers.

[0066] (3) Add 1.22g of (NH4)6Mo7O 24 • Dissolve 4H2O in 4 ml of deionized water, add 9 g of CeO2 nanorods prepared in (2), and load them onto the CeO2 nanorod support using an impregnation method. Dry the prepared precursor in stagnant air. The loading of MoO3 relative to MoO3 / CeO2 is 10 wt%, and the loading of MoO3 relative to CeO2 is 11.1 wt%.

[0067] (4) After drying, the catalyst was reduced in a reaction tube and then carbonized by heating. Hydrogen was introduced into the apparatus and the temperature was raised to 300°C. Starting at 300°C, carbonizing gas (10% methane and 90% hydrogen) was introduced and the temperature was raised to 700°C at a rate of 2°C / min and maintained for 3 hours to complete carbonization and prepare Mo2C / CeO2. The loading of Mo2C relative to CeO2 was 7.86 wt%.

[0068] Example 5

[0069] (1) Dissolve 26.4g Ce(NO3)3·6H2O in 100ml of deionized water and stir magnetically to form cerium precursor solution A. Dissolve 252.0g NaOH in 400ml of deionized water to prepare solution B, and add solution B dropwise to solution A.

[0070] (2) The mixture of A and B was placed in a polytetrafluoroethylene autoclave equipped with a stainless steel autoclave and subjected to hydrothermal treatment at 100°C for 24 hours. After hydrothermal treatment, the precipitate was separated, washed several times with deionized water and ethanol, and then dried in a vacuum oven at 60°C for 12 hours. The dried powder was calcined in a muffle furnace at 500°C for 2 hours to form CeO2 nanorod carriers.

[0071] (3) The sol-gel method was used to separate 3.66g of (NH4)6Mo7O 24·4H2O was dissolved in 10ml of deionized water, 4g of citric acid was added, and 7g of CeO2 nanorods prepared in (2) were added. The mixture was stirred at 80℃ to load the molybdenum salt solution onto the CeO2 nanorod support. The prepared precursor was dried in an oven. The loading of MoO3 relative to MoO3 / CeO2 was 30wt%, and the loading of MoO3 relative to CeO2 was 42.8wt%.

[0072] (4) After drying, the catalyst was reduced in a reaction tube and then carbonized by heating. Hydrogen was introduced into the apparatus and the temperature was raised to 300°C. Starting at 300°C, carbonizing gas (10% methane and 90% hydrogen) was introduced and the temperature was raised to 700°C at a rate of 2°C / min and maintained for 3 hours to complete carbonization and prepare Mo2C / CeO2. The loading of Mo2C relative to CeO2 was 30.34 wt%.

[0073] Comparative Example 1

[0074] (1) Dissolve 26.4g Ce(NO3)3·6H2O in 100ml of deionized water and stir magnetically to form cerium precursor solution A. Dissolve 252.0g NaOH in 400ml of deionized water to prepare solution B, and add solution B dropwise to solution A.

[0075] (2) The mixture of A and B was placed in a polytetrafluoroethylene autoclave equipped with a stainless steel autoclave and subjected to hydrothermal treatment at 100°C for 24 hours. After hydrothermal treatment, the precipitate was separated, washed several times with deionized water and ethanol, and then dried in a vacuum oven at 60°C for 12 hours. The dried powder was calcined in a muffle furnace at 500°C for 2 hours to form CeO2 nanorod carriers.

[0076] (3) The sol-gel method was used to separate 4.88g of (NH4)6Mo7O 24 • Dissolve 4H2O in 10 ml of deionized water, add 5.3 g of citric acid, add 6 g of CeO2 nanorods prepared in (2), stir at 80 °C, and load the molybdenum salt solution onto the CeO2 nanorod support. Dry the prepared precursor in an oven. The loading of MoO3 relative to MoO3 / CeO2 is 40 wt%, and the loading of MoO3 relative to CeO2 is 66.7 wt%.

[0077] (4) After drying, the catalyst was reduced in a reaction tube and then carbonized by heating. Hydrogen was introduced into the apparatus and the temperature was raised to 300°C. Starting at 300°C, carbonizing gas (10% methane and 90% hydrogen) was introduced and the temperature was raised to 700°C at a rate of 2°C / min and maintained for 3 hours to complete carbonization and prepare Mo2C / CeO2. The loading of Mo2C relative to CeO2 was 47.2 wt%.

[0078] Comparative Example 2

[0079] (1) Dissolve 26.4g Ce(NO3)3·6H2O in 100ml of deionized water and stir magnetically to form cerium precursor solution A. Dissolve 252.0g NaOH in 400ml of deionized water to prepare solution B, and add solution B dropwise to solution A.

[0080] (2) The mixture of A and B was placed in a polytetrafluoroethylene autoclave equipped with a stainless steel autoclave and subjected to hydrothermal treatment at 100°C for 24 hours. After hydrothermal treatment, the precipitate was separated, washed several times with deionized water and ethanol, and then dried in a vacuum oven at 60°C for 12 hours. The dried powder was calcined in a muffle furnace at 500°C for 2 hours to form CeO2 nanorod carriers.

[0081] (3) Add 1.22g of (NH4)6Mo7O 24 • Dissolve 4H2O in 4 ml of deionized water, add 9 g of CeO2 nanorods prepared in (2), and load them onto the CeO2 support using an impregnation method. Dry the prepared precursor in stagnant air. The loading of MoO3 relative to MoO3 / CeO2 is 10 wt%, and the loading of MoO3 relative to CeO2 is 11.1 wt%.

[0082] (4) Calcination in a muffle furnace, heating to 700℃ at a rate of 2℃ / min and maintaining for 3 hours to obtain MoO3 / CeO2.

[0083] Comparative Example 3

[0084] (1) 26.4g Ce(NO3)3·6H2O was calcined in a muffle furnace at 500℃ for 2h to form CeO2 support.

[0085] (2) Add 1.22g of (NH4)6Mo7O 24 • Dissolve 4H2O in 4 ml of deionized water, add 9 g of CeO2 prepared in (1), and load it onto the CeO2 support using the impregnation method. Dry the prepared precursor in an oven. The loading of MoO3 relative to MoO3 / CeO2 is 10 wt%, and the loading of MoO3 relative to CeO2 is 11.1 wt%.

[0086] (3) After drying, the catalyst was reduced in a reaction tube and then carbonized by heating. Hydrogen was introduced into the apparatus and the temperature was raised to 300°C. Starting at 300°C, carbonizing gas (10% methane and 90% hydrogen) was introduced and the temperature was raised to 700°C at a rate of 2°C / min and maintained for 3 hours to complete the carbonization and prepare Mo2C / CeO2. The loading of Mo2C relative to CeO2 was 7.86 wt%.

[0087] Catalyst activity testing:

[0088] The catalyst was loaded into the reactor, the feed gas was introduced, and the temperature was raised to the test conditions and maintained at these conditions for 30 minutes. Chromatography was then initiated, with sample analysis lasting 30 minutes. Three consecutive injections were performed, and the average of the three data points was taken.

[0089] Test conditions: catalyst loading 1 mL, temperature: 230℃, pressure: 3.0 MPa, volumetric hourly space velocity 3000 h⁻¹ -1 The volume ratio of H2 to CO2 was 3:1, and the results are shown in Table 1.

[0090] CO2 conversion rate = (CO2 volume content before reaction - CO2 volume content after reaction) / (CO2 volume content before reaction) × 100%;

[0091] Ethanol selectivity = Volume content of C2H6O after reaction / (Volume content of CO after reaction + Volume content of C after reaction) i H x Volume content + C after reaction i H x O y Volume content) × 100%, of which C i H x C i H x O y These represent the volume content of hydrocarbon and alcohol products, respectively.

[0092] Table 1. Catalytic activity evaluation results of the catalyst products from the examples and comparative examples.

[0093]

[0094]

[0095] As shown in Table 1, the conversion rate of carbon dioxide and the selectivity of ethanol were both low when preparing MoO3 / CeO2 nanorod catalysts, when the loading of MoO3 was too high, or when the catalyst was not supported by CeO2 nanorods. The catalyst of this invention exhibits good catalytic performance in the catalytic hydrogenation of carbon dioxide to ethanol, with significantly improved catalytic activity and ethanol selectivity.

[0096] The above embodiments are merely illustrative of the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, without departing from the spirit and substance defined by the claims of the present invention; and such modifications or substitutions are still within the scope defined by the claims of the present invention.

Claims

1. The application of a carbon dioxide hydrogenation catalyst in the hydrogenation of carbon dioxide to ethanol, characterized in that, The carbon dioxide hydrogenation catalyst includes a CeO2 nanorod support and an active component Mo2C loaded on the outer surface of the support. Based on the mass of the CeO2 nanorod support, the loading of the active component Mo2C is 3.5wt%-30.5wt%.

2. The application according to claim 1, characterized in that, The diameter of the CeO2 nanorod support is 8-12 nm.

3. The application according to claim 1, characterized in that, The preparation method of the carbon dioxide hydrogenation catalyst includes the following steps: S1 provides CeO2 nanorod support; S2. Molybdenum salt was loaded onto CeO2 nanorod supports and then dried in air to obtain MoO3 / CeO2. Based on the total mass of CeO2 and MoO3, the loading of MoO3 was 5wt%-30wt%. S3. MoO3 / CeO2 is reduced and carbonized by heating to obtain the carbon dioxide hydrogenation catalyst.

4. The application according to claim 3, characterized in that, The preparation method of CeO2 nanorod support in step S1 includes the following steps: Cerium salt was dissolved in deionized water and magnetically stirred to form an aqueous solution of cerium precursor. A strong alkaline aqueous solution was added dropwise to the aqueous solution of cerium precursor to precipitate, resulting in a mixed suspension. The mixed suspension was placed in a polytetrafluoroethylene autoclave equipped with a stainless steel autoclave for hydrothermal treatment. The precipitate was collected, separated, washed several times with deionized water and ethanol, and then dried in a vacuum oven. The dried powder was calcined in air to obtain CeO2 nanorod carriers.

5. The application according to claim 4, characterized in that, The mass-volume concentration of the cerium precursor aqueous solution is 0.2–0.5 g / ml; the molar concentration of the strong base aqueous solution is 10–20 mol / L; and the volume ratio of the cerium precursor aqueous solution to the strong base aqueous solution is 1:4–6. The hydrothermal treatment temperature is 100–150℃, and the time is 5–24 hours; The calcination temperature is 300–600℃, and the time is 1–4 hours.

6. The application according to claim 3, characterized in that, The load in step S2 includes one of the following methods: Method 1: Molybdenum salt was dissolved in deionized water to form an aqueous solution of molybdenum salt. Citric acid was added, and the solution was boiled in a water bath to make it into a sol. CeO2 nanorod support was then placed in the sol. Method 2: Molybdenum salt was dissolved in deionized water to form an aqueous solution of molybdenum salt, and CeO2 nanorod support was immersed in the aqueous solution of molybdenum salt for equal volume impregnation.

7. The application according to claim 3, characterized in that, In step S3, the reduction includes: introducing hydrogen gas and heating to 300-400℃; Heating carbonization includes: introducing carbonizing gas, heating to 700-800℃ at a heating rate of 2-5℃ / min and maintaining it for 2-4 hours; Carbonized gases include methane and hydrogen, with methane accounting for 10-20% by volume and hydrogen accounting for 80-90% by volume.

8. The application according to claim 1, characterized in that, The reaction conditions for the carbon dioxide hydrogenation catalyst in the preparation of ethanol by carbon dioxide hydrogenation include: a reaction temperature of 200–400°C, a reaction pressure of 2–8 MPa, and a volume hourly space velocity of 2000–6000 h⁻¹. -1 The volume ratio of hydrogen to carbon dioxide is 4:1 to 1:1.

Images