In-situ reduced high-efficiency CO2 methanation catalyst as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of CO2 catalytic conversion, and discloses an in-situ reduction efficient CO2 methanation catalyst as well as a preparation method and application thereof. The efficient CO2 methanation catalyst NiA (CO3) xRe is formed by in-situ reduction of Ni and A coupled carbonate NiA (CO3) x, wherein A is selected from one of Mg, Ce and Al. NiA (CO3) xRe is prepared by a coprecipitation method. According to the present invention, the reaction equilibrium conversion is achieved at 300 DEG C in the reaction atmosphere with the CO2: H2: N2 volume ratio of 1: 4: 5 and the air speed of 150000 mL.gcat <-1 >. H <-1 >, the methane selectivity reaches 100%, the methane yield reaches 677.8 mmol.gcat <-1 >. H <-1 >, and the methane selectivity is still not reduced after the operation is performed for 100 h under the condition; compared with the prior art, the prepared catalyst greatly improves the high efficiency and stability of methanation catalytic reaction, the preparation process is simple, large-scale production is easy to achieve, the catalyst is matched with the temperature of coal-fired flue gas, energy does not need to be input again, efficient conversion can be completed, carbon emission is effectively reduced, and high-value products are obtained for use; and a favorable way is provided for realizing a carbon neutralization target.

Description

Technical Field

[0001] This invention belongs to the field of CO2 catalytic conversion technology, including an in-situ reduction high-efficiency CO2 methanation catalyst, its preparation method and application. Background Technology

[0002] Carbon dioxide (CO2) is one of the most significant anthropogenic greenhouse gases, and its continued emissions are a major cause of global warming. Climate change has become a major challenge hindering sustainable human development. According to a UN IPCC report, the global average temperature in 2023 was approximately 1.32190°C higher than pre-industrial levels (1850–1900). Without effective measures, this increase could reach 6% by 2050, severely impacting ecological and economic systems. Therefore, the Paris Agreement proposes limiting global warming to well below 1.5°C to achieve long-term stability of the climate system.

[0003] Since industrialization, the widespread use of fossil fuels (coal, oil, and natural gas) has led to a continuous increase in CO2 emissions, becoming a major driver of climate change. Despite the ongoing development of renewable energy, the global energy structure will remain dominated by fossil fuels in the short term. Data from the International Energy Agency shows that global energy-related CO2 emissions increased by approximately 0.8% in 2024, adding about 300 million tons, reaching a record high of 37.8 billion tons, with coal accounting for over 40% of these emissions. Excessive CO2 emissions not only contribute to global warming but also cause problems such as ocean acidification and ecological degradation. Achieving efficient resource utilization of CO2 is a key pathway to carbon neutrality. By converting CO2 into high-value-added fuels or chemicals such as methane and methanol, greenhouse gas emission reduction and energy recycling can be achieved simultaneously. Therefore, developing in-situ catalytic systems capable of simultaneously achieving CO2 adsorption and catalytic conversion is of great significance for promoting the closed-loop utilization of carbon resources and the conversion to clean energy.

[0004] In recent years, CO2 utilization technologies have received widespread attention, mainly including its conversion into high-value-added chemicals or fuels such as methane (CH4), carbon monoxide (CO), and methanol (CH3OH). The core lies in developing catalytic systems capable of efficiently and stably activating and converting CO2. Currently, commonly used technical pathways include thermocatalysis, photocatalysis, electrocatalysis, and plasma catalysis. Electrocatalysts are currently the most extensively developed. The amino-modified monobenzene ring copper-based MOFs prepared by CN202511348809.8 possess a unique morphology, with active sites exposed on both the inner and outer surfaces, improving the accessibility of active sites and enhancing reaction mass transfer capabilities. CN120700530A prepared a copper-based metal framework Cu-PTD with N / O co-coordination, exhibiting strong electrocatalytic carbon dioxide reduction and electron transfer capabilities, and high selectivity for the electrocatalytic carbon dioxide reduction products. However, the CO2 concentration in actual industrial exhaust gases is low and often accompanied by other components, making it difficult for electrocatalysis to utilize the energy potential of this heat. In contrast, thermocatalysis is considered the most industrially promising technology due to its stability and ease of continuous operation. However, traditional thermocatalytic reduction catalysts are difficult to directly and efficiently activate CO2 under low concentration conditions and are easily deactivated by fluctuations in the reaction environment. Therefore, developing a catalytic system that combines one-step in-situ reduction of precursors with both CO2 activation and catalysis functions can not only significantly save energy consumption from precursor calcination but also achieve CO2 activation and efficient conversion within the same system, thereby improving reaction efficiency and stability. Based on this, there is an urgent need to develop a low-cost, structurally stable, and easily scalable in-situ reduction high-efficiency CO2 methanation catalyst to meet future application needs for carbon neutrality and energy conversion. Summary of the Invention

[0005] The problem this invention aims to solve is the selectivity and stability issues of current methanation catalysts. It provides a highly efficient and stable CO2 methanation catalyst under in-situ reduction and its simple preparation method. This catalyst can be prepared in large quantities using a simple co-precipitation method. 95% methanation and 677.8 mmol·gcat can be achieved at 300 °C. -1 ·h -1 It features high methane yield and good stability, which greatly contributes to achieving dual-carbon goals.

[0006] To address the current issues of selectivity, yield, and stability, the technical solution adopted in this invention is as follows: This invention provides an in-situ reduction of a highly efficient CO2 methanation catalyst, NiA(CO3)x. Re It is formed by the in-situ reduction of NiA(CO3)x carbonate coupled with Ni and A, wherein A is selected from Mg, Ce and Al.

[0007] Furthermore, the catalyst at 150,000 mL·g cat -1 ·h -1 The reaction was carried out at a space velocity in an atmosphere with a CO2:H2:N2 volume ratio of 1:4:5. The reaction equilibrium yield was reached at 300 °C, with a conversion rate of 95.7% and 100% selectivity for methane. No other byproducts were produced. Furthermore, the reaction was continuously tested at 300 °C for 100 h, and the selectivity for methane remained unchanged, indicating that the invented catalyst has good stability.

[0008] This invention also provides a method for preparing an in-situ reduced, highly efficient CO2 methanation catalyst, comprising the following steps: (1) Add a certain amount of nickel nitrate and citric acid to nitric acid A solution, dissolve them completely to form a mixed solution, and prepare sodium carbonate solution.

[0009] (2) Place the sodium carbonate solution in a water bath and, with vigorous stirring, slowly add the mixed solution dropwise into the sodium carbonate solution; (3) Let it mature in a water bath for a certain period of time with slow stirring; (4) After aging, the precipitate was washed with water and alcohol several times and dried overnight to obtain the product, named NiA(CO3)x; (5) After drying, the catalyst is reduced in situ under a hydrogen atmosphere to obtain a highly efficient CO2 methanation catalyst for in-situ reduction, denoted as NiA(CO3)x Re .

[0010] Furthermore, in step (1), the concentration of nitric acid A solution is 0.95-1.05 mol / L.

[0011] Furthermore, the magnesium nitrate solution is prepared by reacting brucite with nitric acid, with a concentration of 0.95-1.05 mol / L, and a dosage of 40-45 mL.

[0012] Furthermore, in step (1), the molar ratio of citric acid dosage to the total amount of nitric acid A and nickel nitrate metal ions is 1:(9.9-10.1). Furthermore, in step (1), the molar ratio of nickel nitrate to nitric acid A is 1:(1.9-2.1). Furthermore, in step (1), the sodium carbonate solution contains 1.5 times the molar amount required for the carbonation of nitric acid A and nickel nitrate, dissolved in 28-32 mL of water; Furthermore, in step (2), the addition is carried out dropwise using a peristaltic pump at a flow rate of 5-7 mL / min; Furthermore, in step (3), the water bath temperature is 55-65℃, and the maturation time is 2-2.5h; Furthermore, in step (4), the water wash is performed using deionized water 6-7 times, and the alcohol wash is performed using anhydrous ethanol 2-3 times. Furthermore, in step (4), the drying is carried out in a vacuum drying oven at a temperature of 75-85 ℃ for 11-13 h.

[0013] Furthermore, in step (5), the reduction temperature is 445-455 ℃, the reduction time is 1.5-2h, the hydrogen atmosphere consists of 50% hydrogen and 50% nitrogen by volume, and the gas flow rate is 75-85 mL / min.

[0014] The present invention also provides the application of the above-mentioned in-situ reduction high-efficiency CO2 methanation catalyst in carbon dioxide capture and utilization, which can be used in the CO2-containing flue gas emitted by boiler equipment such as thermal power plants.

[0015] The present invention has the following advantages over existing catalysts: (1) This catalyst is prepared by co-precipitation method, which is simple and easy to scale up for industrial use; (2) The active component of the present invention is a simple transition metal nickel. Compared with rare earth and precious metal elements, the raw materials are inexpensive and can greatly reduce the production cost of the catalyst. (3) The catalyst precursor prepared by the present invention does not require calcination oxidation and can be directly reduced and formed in situ in hydrogen, which further saves energy consumption; (4) The Mg, Ce or Al selected in the catalyst prepared by the present invention can assist in CO2 adsorption and activation, realize CO2 enrichment, promote CO2 methanation, and ensure CO2 methanation yield.

[0016] (5) The catalyst prepared in this invention can achieve a conversion rate of over 95% for the methanation of the product, a selectivity of up to 100%, and a methane yield as high as 677.8 mmol·gcat. -1 ·h -1 It is superior to most catalysts; (6) The catalyst prepared by the present invention can maintain stable operation at 300 °C for more than 100 h, and has excellent stability. Attached Figure Description

[0017] Figure 1 This is a graph showing the activity and selectivity of the in-situ reduction methanation catalysts described in Examples 6, 9, and 10.

[0018] Figure 2This is a graph showing the methane yield of the in-situ reduced methanation catalyst described in Examples 6, 9, and 10.

[0019] Figure 3 This is a stability diagram of the in-situ reduction methanation catalyst described in Example 6.

[0020] Figure 4 These are in-situ reduced methanation catalysts from Examples 6, 9, and 10, and their precursor adsorption isotherms from Examples 1, 4, and 5.

[0021] Figure 5 These are the in-situ reduction methanation catalysts of Examples 6, 9, and 10 and their precursor pore size distributions in Examples 1, 4, and 5.

[0022] Figure 6 The attached diagram shows the in-situ reduction of the methanation catalyst after CO2 temperature-programmed dehydrogenation in Examples 6, 9, and 10. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to specific embodiments and accompanying drawings, and the embodiments of the present invention are not limited thereto.

[0024] The formulation elements involved in this invention include, but are not limited to, the elements in the following embodiments, and the preparation methods involved include, but are not limited to, the preparation methods in the following embodiments. Any modifications or equivalent substitutions to the technical solutions of this invention that do not depart from the spirit and scope of the invention should be covered within the protection scope of this invention.

[0025] Example 1 The method is a coprecipitation method. 20 mmol of nickel nitrate and 6 mmol of citric acid were added to 40 mL of a 1 mol / L magnesium nitrate solution prepared by the reaction of nitric acid and brucite, and the mixture was stirred until dissolved to form a mixed solution. Separately, 90 mmol of sodium carbonate was dissolved in 30 mL of deionized water to form a sodium carbonate solution. The sodium carbonate solution was placed in a 60 °C water bath and stirred vigorously. The mixed solution was then added dropwise using a peristaltic pump at a flow rate of 6 mL / min, and the mixture was allowed to mature for 2 h with gentle stirring in the water bath. The precipitate was then washed with water and centrifuged 6 times, washed with anhydrous ethanol and centrifuged twice, and dried in a vacuum drying oven at 80 °C for 12 h to obtain the NiMg(CO3)x precursor.

[0026] Example 2 20 mmol of nickel nitrate and 6 mmol of citric acid were added to 40 mL of a 0.95 mol / L magnesium nitrate solution prepared by the reaction of nitric acid and brucite, and the mixture was stirred to dissolve and form a mixed solution. Separately, 90 mmol of sodium carbonate was dissolved in 30 mL of deionized water to form a sodium carbonate solution. The sodium carbonate solution was placed in a 55°C water bath and stirred vigorously. The mixed solution was then added dropwise using a peristaltic pump at a flow rate of 5 mL / min, and the mixture was allowed to mature under gentle stirring in the water bath for 2.5 h. The precipitate was then washed with water and centrifuged 7 times, washed with anhydrous ethanol and centrifuged 3 times, and dried in a vacuum drying oven at 75°C for 11 h to obtain the NiMg(CO3)x precursor.

[0027] Example 3 20 mmol of nickel nitrate and 6 mmol of citric acid were added to 40 mL of a 1.05 mol / L magnesium nitrate solution prepared by the reaction of nitric acid and brucite, and the mixture was stirred to dissolve and form a mixed solution. Separately, 90 mmol of sodium carbonate was dissolved in 30 mL of deionized water to form a sodium carbonate solution. The sodium carbonate solution was placed in a 65°C water bath and stirred vigorously. The mixed solution was then added dropwise using a peristaltic pump at a flow rate of 7 mL / min, and the mixture was allowed to mature for 2 hours with gentle stirring in the water bath. The precipitate was then washed with water and centrifuged 6 times, washed with anhydrous ethanol and centrifuged twice, and dried in a vacuum drying oven at 85°C for 13 hours to obtain the NiMg(CO3)x precursor.

[0028] Example 4 Add 40 mmol of cerium nitrate, 20 mmol of nickel nitrate, and 6 mmol of citric acid to 40 mL of deionized water and stir to dissolve, forming a mixed solution. Separately, dissolve 120 mmol of sodium carbonate in 30 mL of deionized water to form a sodium carbonate solution. Place the sodium carbonate solution in a 60 °C water bath and stir vigorously. Add the mixed solution dropwise using a peristaltic pump at a flow rate of 6 mL / min and continue to mature under gentle stirring for 2 h. Then, wash the precipitate with water and centrifuge 6 times, wash with anhydrous ethanol and centrifuge 2 times, and dry in a vacuum drying oven at 80 °C for 12 h to obtain the NiCe(CO3)x precursor.

[0029] Example 5 Add 40 mmol of aluminum nitrate, 20 mmol of nickel nitrate, and 6 mmol of citric acid to 40 mL of deionized water and stir to dissolve, forming a mixed solution. Separately, dissolve 120 mmol of sodium carbonate in 30 mL of deionized water to form a sodium carbonate solution. Place the sodium carbonate solution in a 60 °C water bath and stir vigorously. Then, add the mixed solution dropwise using a peristaltic pump at a flow rate of 6 mL / min and continue to mature under gentle stirring for 2 h. Subsequently, wash the precipitate with water and centrifuge 6 times, wash with anhydrous ethanol and centrifuge 2 times, and dry it in a vacuum drying oven at 80 °C for 12 h to obtain the NiAl(CO3)x precursor.

[0030] Example 6 The catalyst was a sample obtained from the in-situ reduction of the precursor obtained in Example 1 in a fixed-bed reactor, followed by performance testing. The in-situ reduction conditions were as follows: the NiMg(CO3)x precursor was placed in a reactor and a mixture of 50% (v / v) H2 and 50% (v / v) N2 gas was introduced and reduced in situ at 450 °C for 1.5 h at a gas flow rate of 80 mL / min, yielding the methanation catalyst NiMg(CO3)x. Re The amount of precursor used is 0.1 g.

[0031] Performance testing employed a programmed temperature ramp-up mode: after in-situ reduction at 450℃, the temperature was lowered to 200℃, and 50% (v / v) CO2 + 50% (v / v) N2 and 50% (v / v) H2 + 50% (v / v) N2 were introduced into a fixed-bed reactor at a volume ratio of 1:4, with a reaction space velocity of 150,000 mL·g. cat -1 ·h -1 The tests were conducted at temperature gradients of 200 ℃, 250 ℃, 300 ℃, 350 ℃, 400 ℃, and 450 ℃, with each temperature increment taking 15 minutes to rise and 60 minutes to maintain.

[0032] Example 7 The catalyst was a sample obtained from the in-situ reduction of the precursor obtained in Example 1 in a fixed-bed reactor, followed by performance testing. The in-situ reduction conditions were as follows: the NiMg(CO3)x precursor was placed in a reactor and a 50% (v / v) H2 + 50% (v / v) N2 mixture was introduced and reduced in situ at 445 °C for 2 h at a gas flow rate of 75 mL / min, yielding the methanation catalyst NiMg(CO3)x. Re The amount of precursor used is 0.1 g.

[0033] Example 8 The catalyst was a sample obtained from the in-situ reduction of the precursor obtained in Example 1 in a fixed-bed reactor, followed by performance testing. The in-situ reduction conditions were as follows: the NiMg(CO3)x precursor was placed in a reactor and a mixture of 50% (v / v) H2 and 50% (v / v) N2 gas was introduced and reduced in situ at 455 °C for 1.5 h at a gas flow rate of 85 mL / min, yielding the methanation catalyst NiMg(CO3)x. Re The amount of precursor used is 0.1 g.

[0034] Example 9 The catalyst was a sample obtained from the in-situ reduction of the precursor obtained in Example 4 in a fixed-bed reactor, followed by performance testing. The in-situ reduction conditions were as follows: the NiCe(CO3)x precursor was placed in a reactor and a 50% H2 + 50% N2 mixture was introduced for in-situ reduction at 450°C for 1.5 h at a gas flow rate of 80 mL / min, yielding the methanation catalyst NiCe(CO3)x. Re The amount of precursor used is 0.1 g.

[0035] Performance testing employed a programmed temperature ramp mode: after in-situ reduction at 450℃, the temperature was lowered to 200℃, and 50% CO2 + 50% N2 and 50% H2 + 50% N2 were introduced into a fixed-bed reactor at a volume ratio of 1:4, with a reaction space velocity of 150,000 mL·g. cat -1 ·h -1 The tests were conducted at temperature gradients of 200 ℃, 250 ℃, 300 ℃, 350 ℃, 400 ℃, and 450 ℃, with each temperature increment taking 15 minutes to rise and 60 minutes to maintain.

[0036] Example 10 The catalyst was a sample obtained from the in-situ reduction of the precursor obtained in Example 5 in a fixed-bed reactor, followed by performance testing. The in-situ reduction conditions were as follows: the NiAl(CO3)x precursor was placed in a reactor and a 50% H2 + 50% N2 mixture was introduced for in-situ reduction at 450°C for 1.5 h at a gas flow rate of 80 mL / min, yielding the methanation catalyst NiAl(CO3)x. Re The amount of precursor used is 0.1 g.

[0037] Performance testing employed a programmed temperature ramp mode: after in-situ reduction at 450℃, the temperature was lowered to 200℃, and 50% CO2 + 50% N2 and 50% H2 + 50% N2 were introduced into a fixed-bed reactor at a volume ratio of 1:4, with a reaction space velocity of 150,000 mL·g. cat -1 ·h -1 The tests were conducted at temperature gradients of 200 ℃, 250 ℃, 300 ℃, 350 ℃, 400 ℃, and 450 ℃, with each temperature increment taking 15 minutes to rise and 60 minutes to maintain.

[0038] Sample Analysis The activity test results of Examples 6, 9, and 10 are as follows: Figure 1 As shown, NiMg(CO3)x ReExample 6 exhibits the best methanation performance, reaching its peak at 300 °C, achieving theoretical equilibrium conversion with a CO2 conversion of 95.7% and a methane selectivity approaching 100%. It is one of the few catalysts currently available capable of achieving such high conversion rates and selectivity. Furthermore, this catalyst utilizes two non-precious metals, Ni and Mg, resulting in low cost and low quantity. The co-precipitation method also facilitates large-scale production, laying a solid foundation for industrialization.

[0039] Figure 2 The methane yields for Examples 6, 9, and 10 are represented by NiMg(CO3)x. Re Example 6 showed the highest methane yield at 300°C, at 677.8 mmol·g. cat -1 ·h -1 This represents the current pinnacle of CO2 methanation technology in the field of thermocatalysis.

[0040] Figure 3 The results of the stability test in Example 6 were obtained under optimal conversion conditions at 300 °C. It was found that after 100 hours of testing, the methane selectivity remained unchanged, and the conversion rate decreased by only 3.2%, indicating that the catalyst has good stability.

[0041] Figure 4 The images show adsorption isotherms of the precursors in Examples 1, 4, and 5, and the in-situ reduced methanation catalysts in Examples 6, 9, and 10. All precursors and their in-situ reduced catalysts exhibit type IV isotherms and H3 hysteresis loops, which are typical characteristics of mesoporous materials.

[0042] Figure 5 The figures show the pore size distribution of the precursors in Examples 1, 4, and 5, and the catalytic reduction after in-situ reduction in Examples 6, 9, and 10 for methanation. The precursors are predominantly mesoporous (2-10 nm), with the NiCe(CO3)x precursor exhibiting additional wider pores (10-50 nm), indicating a richer hierarchical pore structure. The in-situ reduction process triggered a significant evolution in the catalyst texture. Notably, the specific surface area (SSA) of all catalysts decreased dramatically after reduction. According to Table 1, the SSA of NiMg(CO3)x... Re NiCe(CO3)x Re With NiAl(CO3)x Re The specific surface area decreased to 39.7% (114.0 m²) of its precursor. 2 / g), 21.3% (15.1 m) 2 / g) and 26.1% (112.9 m) 2 / g).

[0043] Table 1

[0044] Figure 6 The attached diagrams show the CO2 temperature-programmed desorption of the in-situ reduced methanation catalysts in Examples 6, 9, and 10. Based on the CO2 desorption temperature range, the basicity sites can be classified into three categories: weak (50-200 °C), medium (200-450 °C), and strong (450-800 °C). NiMg(CO3)x Re The catalyst is dominated by weak and medium-alkaline sites, and the desorption peak temperature is relatively low, indicating that the CO2 species adsorbed on its surface have high mobility and reactivity.

[0045] In summary, the present invention has the following advantages over existing catalysts: (1) This catalyst is prepared by co-precipitation method, which is simple and easy to scale up for industrial use; (2) The active component of the present invention is a simple transition metal nickel. Compared with rare earth and precious metal elements, the raw materials are inexpensive and can greatly reduce the production cost of the catalyst. (3) The catalyst precursor prepared by the present invention does not require calcination oxidation and can be directly reduced and formed in situ in hydrogen, which further saves energy consumption; (4) The Mg, Ce or Al selected in the catalyst prepared by the present invention can assist in CO2 adsorption and activation, realize CO2 enrichment, promote CO2 methanation, and ensure CO2 methanation yield.

[0046] (5) The catalyst prepared in this invention can achieve a conversion rate of over 95% for the methanation of the product, a selectivity of up to 100%, and a methane yield as high as 677.8 mmol·gcat. -1 ·h -1 It is superior to most catalysts; (6) The catalyst prepared by the present invention can maintain stable operation at 300 °C for more than 100 h, and has excellent stability.

Claims

1. A highly efficient CO2 methanation catalyst for in-situ reduction, characterized in that, The highly efficient CO2 methanation catalyst NiA(CO3)x Re It is formed by the in-situ reduction of NiA(CO3)x carbonate coupled with Ni and A, wherein A is selected from Mg, Ce and Al.

2. The in-situ reduction high-efficiency CO2 methanation catalyst according to claim 1, characterized in that, The catalyst was used at 150,000 mL·g cat -1 ·h -1 The reaction was carried out at a space velocity in an atmosphere with a CO2:H2:N2 volume ratio of 1:4:

5. The reaction equilibrium yield was reached at 300 °C, with a conversion rate of 95.7%. The selectivity for methane was 100%, and there were no other byproducts. The catalyst exhibited good stability.

3. The method for preparing an in-situ reduction high-efficiency CO2 methanation catalyst as described in claims 1 and 2, characterized in that, Includes the following steps: (1) Add nickel nitrate and citric acid to nitric acid solution A, dissolve them completely to form a mixed solution, and prepare sodium carbonate solution; (2) Place the sodium carbonate solution in a water bath and, with vigorous stirring, slowly add the mixed solution dropwise into the sodium carbonate solution; (3) With gentle stirring, mature in a water bath for a certain period of time; (4) After aging, the precipitate is washed with water and alcohol several times and dried overnight to obtain the product, NiA(CO3)x; (5) After drying, the catalyst is reduced in a hydrogen atmosphere to obtain the highly efficient CO2 methanation catalyst NiA(CO3)x obtained by in-situ reduction. Re .

4. The preparation method according to claim 3, characterized in that, In step (1), the concentration of the nitric acid A solution is 0.95-1.05 mol / L; the molar ratio of nickel nitrate to nitric acid A is 1:(1.9-2.1).

5. The preparation method according to claim 3, characterized in that, In step (1), the sodium carbonate solution contains 1.5 times the amount of sodium carbonate required for the carbonation of nitrate A and nickel nitrate.

6. The preparation method according to claim 3, characterized in that, In step (2), the dripping is performed using a peristaltic pump at a flow rate of 5-7 mL / min.

7. The preparation method according to claim 3, characterized in that, In steps (2) and (3), the temperature of the water bath is 55-65℃, and the curing time is 2-2.5 hours.

8. The preparation method according to claim 3, characterized in that, In step (4), the water washing is performed using deionized water 6-7 times, and the alcohol washing is performed using anhydrous ethanol 2-3 times; the drying is carried out in a vacuum drying oven at a temperature of 75-85 ℃ for 11-13 h.

9. The preparation method according to claim 3, characterized in that, In step (5), the reduction is carried out in a hydrogen atmosphere at a temperature of 445-455 °C for 1.5-2 h. The hydrogen atmosphere consists of 50% hydrogen and 50% nitrogen by volume, and the gas flow rate is 75-85 mL / min.

10. The application of the in-situ reduction high-efficiency CO2 methanation catalyst as described in claim 1 or 2 in carbon dioxide capture and utilization, characterized in that, The high-efficiency CO2 methanation catalyst can be used in the CO2-containing flue gas emitted from boiler equipment such as thermal power plants.

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