Preparation method and application of high-thermal-stability nickel-based catalyst for carbon dioxide methanation reaction

Abstract

This invention discloses a method for preparing a highly thermally stable nickel-based catalyst for the carbon dioxide methanation reaction and its application. The catalyst has a composition of Ni / AlMeO₂. x Me represents one or more of the auxiliary metals Ce, Zr, La, and Zn. The preparation method includes: weighing and mixing Ni source, Al source, and auxiliary metal Me source, grinding them together, transferring the ground solid powder to a ball mill jar, adding a binder (one or more of oxalic acid, citric acid, ammonium bicarbonate, and ascorbic acid), adding ball milling media, and performing ball milling treatment. The product is then dried, ground, and calcined to complete the preparation. This invention enhances the methanation catalytic activity and high-temperature anti-sintering ability of Ni-based catalysts, while the prepared catalyst exhibits higher Ni species dispersion.

Description

Technical Field

[0001] This invention belongs to the field of catalytic synthesis, specifically relating to a method for preparing and applying a highly thermally stable nickel-based catalyst for the methanation of carbon dioxide. Background Technology

[0002] The hydrogenation of carbon dioxide to methane is an important pathway for the efficient energy conversion of carbon dioxide. It can process large quantities of carbon dioxide, increasing its value and alleviating energy shortages. Furthermore, the high-purity methane obtained can be integrated into natural gas pipelines, increasing natural gas reserves. It also enables the long-distance transportation of green hydrogen obtained from water electrolysis, which is of great significance for environmental protection and energy structure upgrading. The carbon dioxide hydrogenation-methane reaction is a strongly exothermic reaction, and its reaction equation is as follows: .

[0003] The methanation reaction releases a large amount of heat, leading to the formation of localized hotspots with temperatures exceeding 500°C. In industrial production, the gas flow rate is even greater, resulting in even higher temperatures at these hotspots. While commercially available Ni / Al₂O₃ catalysts offer high activity and low cost, they are prone to sintering and agglomeration under high-temperature conditions, leading to a decrease in catalyst activity. Therefore, there is an urgent need to develop a CO₂ methanation catalyst with excellent catalytic activity and high thermal stability.

[0004] Currently, methods for synthesizing methanation catalysts include impregnation, hydrothermal synthesis, co-precipitation, and sol-gel methods. For example, Chinese patent CN102029161B discloses a method for synthesizing Ni-based methanation catalysts using a hydrothermal method. This method utilizes the hydrothermal synthesis process to form a catalyst precursor, which is then filtered, washed, dried, calcined, shaped, re-calcined, and reduced to form the catalyst. The hydrothermal method improves the thermal stability of the catalyst. Chinese patent CN101884927B discloses a method for preparing methanation catalysts using an impregnation method. This catalyst uses Ni and Fe as active metals and γ-Al₂O₃ as a support, exhibiting high activity at 350 °C. However, these methods suffer from complex synthesis processes, long synthesis times, high energy consumption, and high activation temperatures. Furthermore, using water as a solvent generates a large amount of wastewater. Therefore, a green, environmentally friendly, and simple method for synthesizing high thermal stability methanation catalysts is needed.

[0005] This invention employs a ball mill-mediated mechanochemical strategy to synthesize Ni / AlMeO with excellent thermal stability. xThe methanation catalyst utilizes the mechanical stress generated during ball milling to highly disperse reducible metals within Al2O3 crystals, forming abundant Me-O-Ni active sites. This improves the stability of Ni species in the catalyst during high-temperature reactions and enhances the thermal stability of oxygen-containing intermediates in the high-temperature hydrogenation conversion of CO2, reducing CO selectivity. Consequently, it strengthens the methanation catalytic activity and high-temperature anti-sintering ability of Ni-based catalysts. Furthermore, this synthesis method avoids the use of solvents, offering advantages such as energy saving, environmental friendliness, simple synthesis steps, and no waste liquid generation. Summary of the Invention

[0006] In view of the above-mentioned technical problems existing in the prior art, the purpose of the present invention is to provide a method for preparing a high thermal stability nickel-based catalyst for carbon dioxide methanation reaction and its application.

[0007] The technical solution adopted in this invention is as follows: A method for preparing a highly thermally stable nickel-based catalyst for the carbon dioxide methanation reaction, wherein the catalyst has the composition Ni / AlMeO₂. x Me represents one or more of the auxiliary metals Ce, Zr, La, and Zn. The preparation method includes the following steps: S1: Weigh out the Ni source, Al source, and auxiliary metal Me source, and mix and grind them together; S2: Transfer the solid powder ground in step S1 to a ball mill jar, add a binder (one or more of oxalic acid, citric acid, ammonium bicarbonate, and ascorbic acid), add ball milling media, and perform ball milling. S3: After ball milling, the product is dried, ground, and then calcined at high temperature in a muffle furnace.

[0008] Furthermore, based on the molar percentage of all metal elements being 100%, the molar content of Ni is 10%-30%, preferably 12%-20%; the molar ratio of Al to Me is 5:1-1:10, preferably 1:1-1.5.

[0009] Furthermore, in step S1, the Ni source, Al source, and Me source are all metal nitrates.

[0010] Furthermore, in step S2, the molar ratio of the adhesive to all metal sources in step S1 is 1-5:1, preferably 1.5-2.5:1.

[0011] Further, in step S2, the ball milling speed is 300-900 rpm, preferably 480-600 rpm, the ball milling time is 0.5h-12h, preferably 1-3h, and the ball-to-material ratio is 1-10:1, preferably 2-5:1.

[0012] Furthermore, in step S3, the high-temperature calcination temperature is 300-550℃, preferably 400-450℃, and the calcination time is 1-5h, preferably 2-3h.

[0013] The present invention also discloses the application of the aforementioned high thermal stability nickel-based catalyst in the catalytic carbon dioxide methanation reaction.

[0014] Furthermore, before catalytic application, the catalyst also includes a step of heating and activating it in a mixed atmosphere of H2 and N2, wherein the volume ratio of H2 to N2 is 1:8-10, the heating and activation temperature is 300-500℃, preferably 400-450℃, and the heating and activation time is 1-6h.

[0015] Compared with the prior art, the beneficial effects achieved by the present invention are: 1. The Ni / AlMeO prepared by this invention x While ensuring low-temperature methanation activity, the catalyst also improves high-temperature catalytic stability, maintaining high methanation catalytic performance even after high-temperature heat treatment.

[0016] 2. This invention utilizes the mechanical stress generated during ball milling to disperse reducible metals in Al2O3 crystals, forming abundant Me-O-Al and Me-O-Ni active sites, which significantly enhances the catalytic activity and high-temperature anti-sintering ability of Ni-based catalysts for methanation. At the same time, the prepared catalyst has a higher Ni species dispersion.

[0017] 3. This invention uses a mechanochemical method to synthesize catalysts, avoiding the use of solvents, and has the advantages of energy saving and environmental protection, simple synthesis steps, and no waste liquid generation. Attached Figure Description

[0018] Figure 1 Comparative Example 1 Ni / Al2O3 catalyst and Example 3 Ni / Al2Ce3O x Comparison of TEM images and particle size distribution of the catalyst. Detailed Implementation

[0019] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0020] Comparative Example 1: Synthesis of a conventional Ni / Al2O3 catalyst 39.23 mmol of Al(NO3)3·9H2O was weighed and dissolved in deionized water, sonicated for 0.5 h, and then placed in a 70 ℃ water bath and stirred continuously at 500 rpm. This solution is denoted as solution A. 8.82 mmol of Na2CO3 was weighed and dissolved in deionized water, and stirred vigorously for 0.5 h until homogeneous. This solution is denoted as solution B. Under constant temperature water bath magnetic stirring, solution B was added dropwise to solution A at a rate of 2.5 mL / min using a microsyringe. After stirring for 2.0 h, the precipitated solid was separated and collected by vacuum filtration and washed three times with deionized water. The collected solid was dried in an oven at 110 ℃ for 12 h, and then calcined in a muffle furnace at 400 ℃ for 3 h to obtain the prepared Al2O3 support. 1.70 mmol of Ni(NO3)2·6H2O was dissolved in deionized water and stirred vigorously to obtain solution C. 0.9 g of Al2O3 support was added to solution C, and stirring was continued for 30 min. The solution was then rotary evaporated at 45 °C for 2 h. The resulting solid was dried in an oven at 110 °C for 12 h, and then calcined in a muffle furnace at 400 °C for 3 h. The resulting catalyst was named Ni / Al2O3(400).

[0021] Example 1: High thermal stability Ni / Al2Ce1O x Catalyst Synthesis Weigh 3.41 mmol Ni(NO3)2·6H2O, 6.37 mmol Ce(NO3)3·6H2O, and 12.74 mmol Al(NO3)3·9H2O and place them in an agate mortar. Grind for 10 min to crush large solid particles. Transfer the solid powder to a 50 mL ball mill jar and add 52.88 mmol H2C2O4·2H2O. Add agate balls to the ball mill jar at a ball-to-powder ratio of 2.5:1, with a small:medium:large ball ratio of 5:3:2 (small ball diameter 8 mm, medium ball diameter 10 mm, large ball diameter 15 mm, the same in the following examples). Stir to ensure uniform dispersion of the solid powder and agate balls. Install the ball mill jar on a ball mill and set the rotation speed to 480 rpm for 1 h. After ball milling, remove the blue paste-like solid from the jar and dry it in a 110 ℃ oven for 12 h. After drying, the sample was ground in an agate mortar for 30 min. Then, the sample was transferred to a muffle furnace and calcined at 400℃ for 3 h. The resulting catalyst was named Ni / Al2Ce1O. x (400).

[0022] Example 2: High thermal stability Ni / Al2Zr1O x Catalyst Synthesis Weigh 3.41 mmol Ni(NO3)2·6H2O, 7.75 mmol Zr(NO3)4·5H2O, and 15.51 mmol Al(NO3)3·9H2O and place them in an agate mortar. Grind for 10 min to crush large solid particles. Transfer the solid powder to a 50 mL ball mill jar and add 63.93 mmol H2C2O4·2H2O. Add agate balls to the jar at a ball-to-powder ratio of 2:1, with a small, medium, and large ball ratio of 5:3:2. Stir to ensure uniform dispersion of the solid powder and agate balls. Install the ball mill jar on a ball mill and set the speed to 480 rpm for 1 h. After ball milling, remove the blue paste-like solid from the jar and dry it in a 110℃ oven for 12 h. After drying, grind the sample in an agate mortar for 30 min. After completion, the sample was transferred to a muffle furnace and calcined at 400℃ for 3 h. The resulting catalyst was named Ni / Al2Zr1O. x (400).

[0023] Example 3: High thermal stability Ni / Al1La1O x Catalyst Synthesis Weigh 3.41 mmol Ni(NO3)2·6H2O, 8.16 mmol La(NO3)3·6H2O, and 8.16 mmol Al(NO3)3·9H2O and place them in an agate mortar. Grind for 10 min to crush large solid particles. Transfer the solid powder to a 50 mL ball mill jar and add 41.83 mmol H2C2O4·2H2O. Add agate balls to the jar, with a ball-to-powder ratio of 3:1, and a ratio of small, medium, and large balls of 5:3:2. Stir to ensure uniform dispersion of the solid powder and agate balls. Install the ball mill jar on a ball mill and set the speed to 480 rpm. Continue ball milling for 1 h. After ball milling, remove the blue paste-like solid from the jar and dry it in a 110℃ oven for 12 h. After drying, grind the sample in an agate mortar for 30 min. After completion, the sample was transferred to a muffle furnace and calcined at 400℃ for 3 h. The resulting catalyst was named Ni / Al1La1O. x (400).

[0024] Example 4: High thermal stability Ni / Al4Ce1O x Catalyst Synthesis Weigh 3.41 mmol Ni(NO3)2·6H2O, 4.64 mmol Ce(NO3)3·6H2O, and 18.56 mmol Al(NO3)3·9H2O and place them in an agate mortar. Grind for 10 min to crush large solid particles. Transfer the solid powder to a 50 mL ball mill jar and add 60.77 mmol H2C2O4·2H2O. Add agate balls to the jar at a ball-to-powder ratio of 2:1, with a small, medium, and large ball ratio of 5:3:2. Stir to ensure uniform dispersion of the solid powder and agate balls. Install the ball mill jar on a ball mill and set the speed to 480 rpm for 1 h. After ball milling, remove the blue paste-like solid from the jar and dry it in a 110℃ oven for 12 h. After drying, grind the sample in an agate mortar for 30 min. After completion, the sample was transferred to a muffle furnace and calcined at 400 °C for 3 h. The resulting catalyst was named Ni / Al4Ce1O. x (400).

[0025] Example 5: High thermal stability Ni / Al1Ce1O x Catalyst Synthesis Weigh 3.41 mmol Ni(NO3)2·6H2O, 7.82 mmol Ce(NO3)3·6H2O, and 7.82 mmol Al(NO3)3·9H2O and place them in an agate mortar. Grind for 10 min to crush large solid particles. Transfer the solid powder to a 50 mL ball mill jar and add 46.56 mmol H2C2O4·2H2O. Add agate balls to the jar at a ball-to-powder ratio of 3:1, with a small, medium, and large ball ratio of 5:3:2. Stir to ensure uniform dispersion of the solid powder and agate balls. Install the ball mill jar on a ball mill and set the speed to 480 rpm. Continue ball milling for 1 h. After ball milling, remove the blue paste-like solid from the jar and dry it in a 110℃ oven for 12 h. After drying, grind the sample in an agate mortar for 30 min. After the process, the sample was transferred to a muffle furnace and calcined at 400 °C for 3 h. The resulting catalyst was named Ni / Al1Ce1O. x (400).

[0026] Example 6: High thermal stability Ni / Al2Ce3O x Catalyst Synthesis Weigh 3.41 mmol Ni(NO3)2·6H2O, 8.47 mmol Ce(NO3)3·6H2O, and 5.65 mmol Al(NO3)3·9H2O and place them in an agate mortar. Grind for 10 min to crush large solid particles. Transfer the solid powder to a 50 mL ball mill jar and add 43.41 mmol H2C2O4·2H2O. Add agate balls to the jar, with a ball-to-powder ratio of 3:1, and a ratio of small, medium, and large balls of 5:3:2. Stir to ensure uniform dispersion of the solid powder and agate balls. Install the ball mill jar on a ball mill and set the speed to 480 rpm. Continue ball milling for 1 h. After ball milling, remove the blue paste-like solid from the jar and dry it in a 110℃ oven for 12 h. After drying, grind the sample in an agate mortar for 30 min. After completion, the sample was transferred to a muffle furnace and calcined at 400 °C for 3 h. The resulting catalyst was named Ni / Al2Ce3O x (400).

[0027] Example 7: High thermal stability Ni / Al2Ce5O x Catalyst Synthesis Weigh 3.41 mmol Ni(NO3)2·6H2O, 9.06 mmol Ce(NO3)3·6H2O, and 3.62 mmol Al(NO3)3·9H2O and place them in an agate mortar. Grind for 10 min to crush large solid particles. Transfer the solid powder to a 50 mL ball mill jar and add 41.83 mmol H2C2O4·2H2O. Add agate balls to the jar at a ball-to-powder ratio of 3:1, with a small, medium, and large ball ratio of 5:3:2. Stir to ensure uniform dispersion of the solid powder and agate balls. Install the ball mill jar on a ball mill and set the speed to 480 rpm for 1 h. After ball milling, remove the blue paste-like solid from the jar and dry it in a 110℃ oven for 12 h. After drying, grind the sample in an agate mortar for 30 min. After completion, the sample was transferred to a muffle furnace and calcined at 400 °C for 3 h. The resulting catalyst was named Ni / Al2Ce5O. x (400).

[0028] Example 8: High thermal stability Ni / Al2Ce3O x Synthesis with NH4HCO3 catalyst Weigh 3.41 mmol Ni(NO3)2·6H2O, 8.47 mmol Ce(NO3)3·6H2O, and 5.65 mmol Al(NO3)3·9H2O and place them in an agate mortar. Grind for 10 min to crush large solid particles. Transfer the solid powder to a 50 mL ball mill jar and add 43.41 mmol NH4HCO3. Add agate balls to the jar at a ball-to-powder ratio of 3:1, with a small, medium, and large ball ratio of 5:3:2. Stir to ensure uniform dispersion of the solid powder and agate balls. Install the ball mill jar on a ball mill and set the rotation speed to 480 rpm for 1 h. After ball milling, remove the blue paste-like solid from the jar and dry it in a 110 ℃ oven for 12 h. After drying, grind the sample in an agate mortar for 30 min. After completion, the sample was transferred to a muffle furnace and calcined at 400 °C for 3 h. The resulting catalyst was named Ni / Al2Ce3O x -NH4HCO3 (400).

[0029] Example 9: High thermal stability Ni / Al2Ce3O x Synthesis of -C6H8O7 catalyst Weigh 3.41 mmol Ni(NO3)2·6H2O, 8.47 mmol Ce(NO3)3·6H2O, and 5.65 mmol Al(NO3)3·9H2O and place them in an agate mortar. Grind for 10 min to crush large solid particles. Transfer the solid powder to a 50 mL ball mill jar and add 43.41 mmol C6H8O7 (citric acid). Add agate balls to the jar at a ball-to-powder ratio of 3:1, with a small, medium, and large ball ratio of 5:3:2. Stir to ensure uniform dispersion of the solid powder and agate balls. Install the ball mill jar on a ball mill and set the speed to 480 rpm for 1 h. After ball milling, remove the blue paste-like solid from the jar and dry it in a 110℃ oven for 12 h. After drying, grind the sample in an agate mortar for 30 min. After completion, the sample was transferred to a muffle furnace and calcined at 400 °C for 3 h. The resulting catalyst was named Ni / Al2Ce3O x -C6H8O7 (400).

[0030] Example 10: High thermal stability Ni / Al2Ce3O x Synthesis of -C6H8O6 catalyst Weigh 3.41 mmol Ni(NO3)2·6H2O, 8.47 mmol Ce(NO3)3·6H2O, and 5.65 mmol Al(NO3)3·9H2O and place them in an agate mortar. Grind for 10 min to crush large solid particles. Transfer the solid powder to a 50 mL ball mill jar and add 43.41 mmol C6H8O6 (ascorbic acid). Add agate balls to the jar at a ball-to-powder ratio of 3:1, with a small, medium, and large ball ratio of 5:3:2. Stir to ensure uniform dispersion of the solid powder and agate balls. Install the ball mill jar on a ball mill and set the speed to 480 rpm for 1 h. After ball milling, remove the blue paste-like solid from the jar and dry it in a 110 ℃ oven for 12 h. After drying, grind the sample in an agate mortar for 30 min. After completion, the sample was transferred to a muffle furnace and calcined at 400 °C for 3 h. The resulting catalyst was named Ni / Al2Ce3O x -C6H8O6(400).

[0031] Example 11: Preparation of green methane by CO2 hydrogenation CO2 hydrogenation was carried out in a stainless steel tubular fixed-bed reactor with a quartz liner. The catalysts prepared in Comparative Example 1 and Examples 1-10 were first pressed into tablets, then crushed, and screened to a size of 60-80 mesh. These tablets were then loaded into the quartz liner of the stainless steel reaction tube. Quartz wool was used to fix the catalyst particles in the middle of the reaction tube before it was installed on the fixed-bed reactor. The fixed-bed pressure was adjusted to 2.0 MPa using nitrogen, and a leak test was performed. No significant pressure drop within 0.5 h indicated good sealing. After purging the high-pressure nitrogen, a hydrogen-nitrogen mixture was used to replace the nitrogen at atmospheric pressure. The hydrogen flow rate was adjusted to 5 mL / min, and the nitrogen flow rate to 45 mL / min. The catalyst was activated by reduction at 450 °C for 3 h. After catalyst activation, a mixed gas (CO2:H2:N2 volume ratio = 18:72:10) was used at atmospheric pressure and a reaction temperature of 250-300 °C. The gas hourly space velocity (GHSV) during the hydromethanation reaction was 60,000 h⁻¹. -1 After the reaction reaches steady state, the gaseous products are detected online using a multichannel gas chromatograph (GC9790Ⅱ) equipped with TCD and FID detectors. The conversion rate of carbon dioxide is calculated using the internal standard method based on the peak areas of various gases obtained in the chromatogram.

[0032] Table 1 shows the Ni / AlMeO synthesized using different embodiments. xActivity data for CO2 hydrogenation methanation using a fixed-bed reactor were obtained for the (400) catalyst and the Ni / Al2O3 (400) catalyst of Comparative Example 1. Reaction conditions: atmospheric pressure, temperature 250-280 °C, gas feedstock composition (volume ratio CO2:H2:N2 = 18:72:10), and gas hourly space velocity (GHSV) 60000 h⁻¹. -1 As the reaction temperature increases, the CO2 conversion rate increases, as seen in the Ni / AlMeO3 example. x (400) The catalyst exhibits significantly better activity than traditional Ni / Al2O3 catalysts. This is because the mechanical stress disperses reducible metal elements within the Al2O3 crystals, creating abundant Me-O-Ni active sites. This enhances the adsorption and activation capacity of Ni species for CO2, thereby improving the methanation catalytic activity. Among these, Ni / Al2Ce1O... x The (400) catalyst exhibited a high CO2 conversion rate of 74.8% at 250 °C.

[0033] Table 1 High thermal stability Ni / MeO x CO2 hydromethaneation activity data of (400) .

[0034] To compare the thermal stability of the various catalysts, high-temperature heat treatment was performed. Ni / AlMeO4 synthesized in different embodiments was compared. x The (400) catalyst and the Ni / Al2O3 (400) catalyst of Comparative Example 1 were calcined in a muffle furnace at 900 °C for 10 h. The product was collected, which is the heat-treated Ni / AlMeO3. x (900) catalyst or Ni / Al2O3 (900) catalyst.

[0035] Table 2 shows the activity data of the catalyst after high-temperature heat treatment (i.e., calcination at 900℃ for 10 h) for CO2 methanation. The reaction conditions were: atmospheric pressure, temperature 280-300℃, gaseous feedstock composition CO2:H2:N2 volume ratio CO2:H2:N2 = 18:72:10, and gas hourly space velocity (GHSV) 60000 h⁻¹. -1 As the reaction temperature increases, the CO2 conversion rate increases, as seen in the Ni / AlMeO3 example. xThe (900) catalyst exhibits a significantly smaller catalytic activity loss after high-temperature treatment compared to the traditional Ni / Al2O3 (900) catalyst. This is because the mechanical stress generated during ball milling improves the dispersion of Ni species, thereby suppressing sintering and agglomeration. Simultaneously, the formed Me-O-Ni active sites enhance the catalyst's stability during high-temperature reactions, thus strengthening the high-temperature anti-sintering ability of the Ni-based catalyst. Ni / Al2Ce1O x The (900) catalyst exhibited the best CO2 conversion rate and excellent high-temperature resistance to sintering, with the CO2 conversion rate decreasing by only 18.1% at 280 °C.

[0036] Table 2 High thermal stability Ni / AlMeO x CO2 hydromethaneation activity data of (900) .

[0037] Table 3 shows the Ni / Al ratios for different Al:Ce molar ratios. a Ce b O x (400) Activity data of the catalyst in a fixed-bed reactor for CO2 hydrogenation methanation. Reaction conditions: atmospheric pressure, temperature 250-280 °C, gas feedstock composition CO2:H2:N2 volume ratio CO2:H2:N2 = 18:72:10, gas hourly space velocity (GHSV) 60000 h⁻¹. -1 When the molar ratio of Al:Ce is 2:3, Ni / Al2Ce3O x (400) catalyst exhibits the best CO2 conversion rate, reaching 80.6% at 250℃.

[0038] Table 3 High thermal stability Ni / Al a Ce b O x CO2 hydromethaneation activity data of (400) .

[0039] Table 4 shows the activity data of the catalyst after high-temperature heat treatment for CO2 hydrogenation methanation. Reaction conditions: atmospheric pressure, temperature 280-300 °C, gaseous feedstock composition (volume ratio CO2:H2:N2 = 18:72:10), gas hourly space velocity (GHSV) 60,000 h⁻¹. -1 In the examples, the Al:Ce molar ratio is 2:3 for Ni / Al2Ce3O. x The (900) catalyst exhibited a high CO2 conversion rate, with the CO2 conversion rate decreasing by only 7.0% at 280 °C, demonstrating high thermal stability.

[0040] Table 4 High thermal stability Ni / Al a Ce b O x CO2 hydromethaneation activity data of (900) .

[0041] Table 5 shows the Ni / Al2Ce3O prepared using different adhesives. x Activity data of the catalyst in CO2 hydrogenation methanation using a fixed-bed reactor. Operating conditions: atmospheric pressure, temperature 250-280 °C, gas feedstock composition (volume ratio: CO2:H2:N2 = 18:72:10), gas hourly space velocity (GHSV) 60,000 h⁻¹. -1 Among them, Ni / Al2Ce3O uses oxalic acid as an adhesive. x The catalyst exhibited the best CO2 conversion rate and maintained optimal catalytic activity even after high-temperature heat treatment.

[0042] Table 5 Different adhesives Ni / Al2Ce3O x CO2 hydrogenation methanation activity data .

[0043] Table 6 lists the traditional Ni / Al2O3 catalyst and the Ni / Al2Ce1O catalyst used in the examples. x (400), Ni / Al2Ce3O x (400) BET results table. Example Ni / MeO x The catalyst has a larger specific surface area, which helps to improve the dispersion of active metal Ni and enhances the thermal stability of the catalyst.

[0044] Table 6 Catalyst BET Data Results .

[0045] Figure 1 Ni / Al2O3 catalyst and Ni / Al2Ce3O x TEM image of the catalyst. Figure 1 The sub-figures (a) and (b) show the TEM image and particle size distribution of the Ni / Al2O3 catalyst in Comparative Example 1, respectively. Figure 1 Figures (c) and (d) respectively show the Ni / Al2Ce3O of Example 3. x TEM image and particle size distribution of the catalyst.

[0046] It can be seen that the particle size of the catalyst in the traditional Ni / Al2O3 catalyst is 23.31 nm, while that in Ni / Al2Ce3O xThe catalyst particles have a diameter of 8.31 nm, and the particle size of the active species Ni in the catalyst is reduced by 6 nm from 20 nm. This demonstrates that the synthesis scheme of the present invention can effectively reduce the particle size of the catalyst, improve the dispersion of the active metal Ni, thereby reducing the agglomeration and sintering of Ni species and improving the thermal stability of the catalyst.

[0047] The contents described in this specification are merely an enumeration of the implementation forms of the inventive concept, and the scope of protection of this invention should not be regarded as limited to the specific forms described in the embodiments.

Claims

1. A method for preparing a high-thermal-stability nickel-based catalyst for carbon dioxide methanation reaction, characterized in that, The catalyst has a composition of Ni / AlMeO x Me represents one or more of the auxiliary metals Ce, Zr, La, Zn, and the preparation method comprises the following steps: S1: Weigh out the Ni source, Al source, and auxiliary metal Me source, and mix and grind them together; S2: Transfer the solid powder ground in step S1 to a ball mill jar, add a binder (one or more of oxalic acid, citric acid, ammonium bicarbonate, and ascorbic acid), add ball milling media, and perform ball milling. S3: After ball milling, the product is dried, ground, and then calcined at high temperature in a muffle furnace.

2. The method for preparing a highly thermally stable nickel-based catalyst for carbon dioxide methanation reaction as described in claim 1, characterized in that, Based on the molar percentage of all metal elements being 100%, the molar content of Ni is 10%-30%, preferably 12%-20%; the molar ratio of Al to Me is 5:1-1:10, preferably 1:1-1.

5.

3. The method for preparing a highly thermally stable nickel-based catalyst for carbon dioxide methanation reaction as described in claim 1, characterized in that, In step S1, the Ni source, Al source, and Me source are all metal nitrates.

4. The method for preparing a highly thermally stable nickel-based catalyst for carbon dioxide methanation reaction as described in claim 1, characterized in that, In step S2, the molar ratio of the adhesive to all metal sources in step S1 is 1-5:1, preferably 1.5-2.5:

1.

5. The method for preparing a highly thermally stable nickel-based catalyst for carbon dioxide methanation reaction as described in claim 1, characterized in that, In step S2, the ball milling speed is 300-900 rpm, preferably 480-600 rpm, the ball milling time is 0.5h-12h, preferably 1-3h, and the ball-to-material ratio is 1-10:1, preferably 2-5:

1.

6. The method for preparing a highly thermally stable nickel-based catalyst for carbon dioxide methanation reaction as described in claim 1, characterized in that, In step S3, the high-temperature calcination temperature is 300-550℃, preferably 400-450℃, and the calcination time is 1-5h, preferably 2-3h.

7. A high thermal stability nickel-based catalyst prepared by any one of the methods described in claims 1-6.

8. The application of the high thermal stability nickel-based catalyst as described in claim 7 in the catalytic methanation of carbon dioxide.

9. The application as described in claim 8, characterized in that, Before catalytic application, the catalyst also includes a heating activation step in a mixed atmosphere of H2-N2, where the volume ratio of H2 to N2 is 1:8-10, the heating activation temperature is 300-500℃, preferably 400-450℃, and the heating activation time is 1-6h.

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