Solid reverse-direction catalyst, method for producing the same, and use of the catalyst in carbon dioxide methane at low temperatures.

Abstract

The present invention discloses a solid reverse catalyst and its manufacturing method, as well as its use in the catalyst for carbon dioxide methanation at low temperatures. In the present invention, a single metal or alloy component having the ability to dissociate hydrogen gas is used as the support phase, and metal oxide nanoparticles that generate oxygen vacancies and adsorb activated carbon dioxide are used as the support phase. At the interface of the catalyst produced, the oxide nanoparticles are supported on the metal surface, which is different from the conventional catalyst in which the metal is supported on the surface of the oxide support, making it a novel solid reverse catalyst. Under certain reaction conditions, the reverse catalyst produced by the present invention is applied to the carbon dioxide methanation reaction, and the catalyst can be used at a low temperature of 200°C or less and at a high reaction space velocity (127,000 h -1 ) has superior performance to most previously reported catalysts, with methane selectivity reaching >99% and methane production rate reaching 50g / methane. CH4 / g cat / h and shows excellent stability even after long-term operation of 1500 hours.

Description

[Technical Field]

[0001] This invention relates to a solid reverse catalyst, a method for producing the same, and its application in the multiphase catalytic reaction of hydrogenation and methane of carbon dioxide. [Background technology]

[0002] Humanity's over-extraction and use of fossil fuels has resulted in massive CO2 emissions, causing a series of serious environmental problems including climate anomalies, sea-level rise, glacial retreat, permafrost thawing, and a decline in flora and fauna biodiversity. Capturing CO2 from factory exhaust gases and converting it into methane, methanol, or other high-value chemicals is a compatible solution to address both environmental pollution and energy shortages. CO2 methane conversion has broad potential in energy conversion and H2 energy storage applications.

[0003] [ka] The CO2 methane reaction (Equation 1) has a thermodynamic enthalpy change of -165.1 kJ / mol. -1 As this is a strongly exothermic reaction, the reaction process is thermodynamically favorable at low temperatures. However, the reduction of CO2 to CH4 involves the transfer of eight electrons, and a high kinetic barrier exists in the hydrogenation process, usually requiring high operating temperatures (>300°C) to obtain a satisfactory space-time yield of CH4. However, excessively high reaction temperatures not only suppress CO2 methane production but also favor the occurrence of the side reaction, the reverse steam conversion reaction (equation 2). The resulting by-product CO requires further separation and purification steps of CH4 for subsequent energy utilization, increasing the cost of using CH4 as fuel and weakening the applicability advantage of CO2 methane. Therefore, the design and development of inexpensive, low-temperature, and highly efficient CO2 methane catalysts can effectively promote the practical application of CO2 methane and enhance its competitiveness.

[0004] Conventional designs for producing methane catalysts by CO2 hydrogenation at low temperatures primarily focus on metal / oxide-supported catalysts formed from metal nanoparticles and oxide bases. At the interface of conventional metal / oxide catalysts, oxygen-containing intermediates partially adsorbed on the oxide moiety typically exhibit extremely high thermodynamic stability, resulting in a high hydrogenation conversion energy barrier, making them prone to occupying the active site and significantly reducing the catalyst's low-temperature activity. Reverse oxide / metal catalysts, formed by oxide clusters supported on a metal support, possess a different interface structure than conventional metal / oxide catalysts, potentially improving the conversion rate of oxygen-containing intermediates, altering the reaction pathway, and enhancing catalytic performance. Furthermore, in practical applications, the cost of some metals (e.g., iron, cobalt, nickel, copper) is roughly the same as or even lower than that of oxides. Therefore, designing reverse oxide / metal structures offers new opportunities for the production of highly efficient CO2 hydrogenation catalysts.

[0005] This invention provides a solid reverse catalyst in which oxide nanoparticles are supported on a metal support, and a method for producing the same, wherein the reverse catalyst can be used under low temperature conditions of 200°C or lower and with a high reaction space rate (127,000 h) -1 ) possesses CO2 methanation activity that surpasses the majority of previously reported catalysts, with methane selectivity >99%, and a methane production rate of 50g CH4 / g cat It was demonstrated that the reverse-direction catalyst could reach a certain level of 1500 hours of operation and exhibited excellent stability even after prolonged operation. [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The object of the present invention is to provide a solid reverse catalyst and a method for producing the same, wherein the catalyst of the present invention can realize a CO2 methane process with high conversion rate, high selectivity, and high stability under low temperature conditions. [Means for solving the problem]

[0007] The technical proposal of this invention is as follows:

[0008] A solid reverse catalyst, which uses a metal that dissociates hydrogen gas as a carrier, a nano-oxide that generates oxygen vacancies and adsorbs activated carbon dioxide as a supported phase, uniformly disperses the nano-oxide on the surface of the metal carrier, and has a nano-oxide / metal reverse interface structure. The carrier metal is one or more selected from cobalt, nickel, aluminum, copper, and ruthenium. The supported-phase nano-oxide is one or more selected from titanium oxide, aluminum oxide, manganese oxide, cerium oxide, zirconium oxide, silicon oxide, and tungsten oxide. The molar fraction of the supported-phase metal is 0.01 to 30% with respect to the total molar amount of the metals in the carrier and the supported phase.

[0009] The method for manufacturing the solid reverse catalyst described in the present invention includes manufacturing a carrier precursor by a hydrothermal method or a coprecipitation method under conditions of an appropriate precipitant and solvent, manufacturing a nano-oxide dispersion by a sol method under conditions of an appropriate precipitant, solvent, and protective agent, Precipitation method , Soaking method and other methods to deposit and precipitate or immerse the nano-oxide on the carrier precursor in situ, firing the obtained powdery solid, and reducing it. After that, uniformly disperse the nano-oxide that occupies at least on the surface of the metal carrier to obtain a solid reverse catalyst.

[0010] Preferably, the method for manufacturing the solid reverse catalyst described in the present invention includes the following steps (1) and (2). (1) In the synthesis of the nano-oxide, The precursor salt of the supported phase is dissolved in a solvent, the resulting solution (concentration 0.01-5 mol / L) is added to a precipitating agent solution (concentration 0.01-5 mol / L) to obtain a hydroxide sol, the obtained hydroxide sol is added to ethanol to obtain a hydroxide-ethanol sol, the hydroxide-ethanol sol is dispersed in a mixed solution of oleic acid / oleylamine / ethanol, stirred uniformly, transferred to an autoclave, sealed, and subjected to solvent heat treatment at 80-220°C for 1-24 hours, after which the solid product is collected, washed with deionized water to neutralize the pH of the washing solution, freeze-dried to obtain nanooxides, and dispersed in ethanol to obtain a nanooxide dispersion. In step (1), the precursor salt of the supported phase is one or more selected from titanium tetrachloride, tetrabutyl titanate, aluminum nitrate, aluminum nitrate hydrate, aluminum chloride, manganese nitrate, manganese nitrate hydrate, manganese chloride, cerium nitrate, cerium nitrate hydrate, cerium chloride, zirconium nitrate, zirconium nitrate hydrate, zirconium chloride, tetraethyl orthosilicate, ammonium metatungstate, sodium tungstate, and tungsten chloride. The solvent is one or more selected from water, methanol, ethanol, butanol, tetrahydrofuran, and methyl t-butyl ether. The precipitating agents are ammonium carbonate, aqueous ammonia, urea, sodium hydroxide, sodium bicarbonate, Oxalic acid Ammonium, Oxalic acid One or more selected from, (2) Synthesis of solid reverse catalysts Precipitation method ) in The precursor salt of the support is dissolved in a solvent, the nanooxide dispersion (concentration 0.01-5 mol / L) produced in step (1) is added dropwise to the resulting solution (concentration 0.01-5 mol / L), and the precipitating agent solution is added dropwise while stirring to control the pH to =9, then aged at room temperature, filtered, washed, dried, calcined in still air, and after calcination, reduced in a hydrogen gas atmosphere to produce a solid reverse catalyst. In step (2), the precursor salt of the carrier is one or more selected from cobalt nitrate, cobalt nitrate hydrate, cobalt chloride, nickel nitrate, nickel nitrate hydrate, nickel chloride, copper nitrate, copper nitrate hydrate, cupric chloride, and ruthenium chloride. The solvent is one or more selected from water, methanol, ethanol, butanol, tetrahydrofuran, and methyl t-butyl ether. The precipitating agents are ammonium carbonate, aqueous ammonia, urea, sodium hydroxide, sodium bicarbonate, Oxalic acid Ammonium, Oxalic acid One or more selected from, The optimal aging time is 1 to 24 hours. The preferred drying temperature is 40-200°C, and the drying time is 1-24 hours. The preferred firing temperature is 200-600°C, and the firing time is 1-12 hours. The preferred reduction temperature is 200-700°C, the duration is 1-6 hours, the preferred hydrogen gas concentration range in the reducing atmosphere is 5-100%, and the total flow rate range is 5-100 ml / min. The particle size of the solid reverse-direction catalyst produced is 10 to 200 mesh.

[0011] The solid reverse catalyst described in the present invention can be applied to the carbon dioxide methanation reaction. Specific application methods are as follows: This involves placing a solid reverse catalyst in a fixed-bed reactor, with a molar ratio of carbon dioxide to hydrogen gas flowing in the reaction gases of 1:4, and a space velocity of 9,000 to 127,000 h⁻¹ per gas hour. -1 The reaction pressure range is atmospheric pressure to 6 MPa, and the reaction temperature range is 25 to 450°C. The catalyst stability experiment results showed that it operated stably for 1500 hours, maintaining a carbon dioxide conversion rate of approximately 90%, with a methane selectivity of >99%, a suitable reaction temperature of 200°C, and atmospheric pressure. [Effects of the Invention]

[0012] The advantages of the present invention are as follows:

[0013] The oxide / metal reverse catalyst produced can catalyze the carbon dioxide methanation reaction with high conversion rate, high selectivity, and high stability at low temperatures (not exceeding 200°C) and atmospheric pressure conditions. Under high space velocity conditions, the conversion rate of carbon dioxide is greater than 80%, and the selectivity of methane is >99%. Conventional metal / oxide catalysts all require temperatures and pressure conditions of 250°C or higher to achieve the activity of the present invention. Furthermore, the solid reverse catalyst produced by the present invention exhibits good stability in the carbon dioxide hydrogenation reaction system and can be used for long periods of time or in multiple cycles. [Brief explanation of the drawing]

[0014] [Figure 1] This is a thermodynamic diagram showing the temperature-dependent changes in the CO2 methane reaction and its side reaction, the reverse water vapor conversion reaction. [Figure 2] These are the reaction results of the catalyst at different temperatures in one embodiment. [Figure 3] This shows the reaction results of a catalyst at different gas-time space velocities in one embodiment. [Figure 4] This shows the test results for the CO2 conversion rate and CH4 selectivity of a catalyst within 1500 hours in one embodiment. [Figure 5] This is a study on the effect of different precipitants on the methanation activity of the reverse catalyst in one embodiment. [Figure 6] This is a comparison of the methanation activity of metal oxide cluster catalysts supported on different metal supports in one embodiment. [Figure 7] This is a comparison of the methanation activity of a binary reverse catalyst in one embodiment and a conventional forward catalyst. [Figure 8] This is a HAADF-STEM image of the catalyst produced in Example 1. [Modes for carrying out the invention]

[0015] To better understand the purpose, technical proposal, and advantages of this application, the application will be described in more detail below with reference to the drawings and examples. Clearly, the examples described are only a selection of the examples of this application, not all of them. All other technical proposals acquired by those skilled in the art based on the examples of this application are within the scope of protection of this application.

[0016] Conventional methanation catalysts are typically manufactured by methods such as immersion or liquid-phase reduction. In catalysts manufactured using these methods, after calcination and reduction steps, the small amount of metal components are dispersed on the oxide support in the form of nanoparticles, further forming a metal / oxide interface structure. Conventional carbon dioxide methanation catalysts typically use oxides such as cerium oxide, zirconium oxide, aluminum oxide, silicon oxide, and titanium oxide as the support phase, with a mole fraction of approximately 50% to 99.9% of the catalyst, providing oxygen vacancies to dissociate carbon dioxide. Metals such as iron, cobalt, nickel, copper, ruthenium, rhodium, palladium, and platinum, with a mole fraction of approximately 0.01% to 30% of the catalyst, are used as the catalyst support phase for dissociating hydrogen gas. Conventional forward-oriented catalysts often require temperatures above 250°C to catalyze the methanation reaction. Furthermore, the active centers of the supported nanoparticles tend to aggregate and become inactive in strongly exothermic reaction systems. In addition, the highly unsaturated coordination of the nanoparticles also easily leads to catalyst deposit and deactivation.

[0017] In this invention, a reverse catalyst obtained using a metal that dissociates hydrogen gas as the support phase and an oxide that generates oxygen vacancies and adsorbs activated carbon dioxide as the supporting phase can realize the carbon dioxide methane process at a high space velocity, with high activity and selectivity at temperatures below 200°C, and has high-temperature cycle stability at 450°C. By using a continuous phase metal as the support, surface coordination unsaturation is reduced, and deposit formation is suppressed. In one specific embodiment, the space velocity per gas hour is 9000 to 127000 h. -1 The carbon dioxide conversion rate is >80%, the methane selectivity is >99%, and the stability exceeds 1500 h. The specific synthesis method is as follows.

[0018] 1. Synthesis of nanooxides A precursor salt or hydrate corresponding to one or more metals that create oxygen deficiencies and adsorb activated carbon dioxide is dissolved in a solvent at a constant concentration (0.01 mol / L to 5 mol / L), stirred until completely dissolved, and then added to a precipitant solution to obtain a hydroxide sol. The obtained sol is then added to ethanol to obtain a hydroxide-ethanol sol. A certain amount of hydroxide sol is dispersed in a mixed solution of oleic acid, oleylamine, and ethanol, stirred uniformly, and transferred to a 100 ml polytetrafluoroethylene-lined autoclave. The autoclave is then sealed and subjected to solvent heat treatment at a constant temperature (80°C-220°C) for a period of time (1-24 hours). The obtained precursor is washed multiple times with deionized water until the pH of the washing solution becomes neutral, freeze-dried overnight to obtain nanooxides, and then dissolved in ethanol to obtain a transparent dispersion of nanooxides.

[0019] The above method is applicable to the synthesis of the following nanooxides or mixed oxides (titanium oxide, aluminum oxide, manganese oxide, cerium oxide, zirconium oxide, silicon oxide, tungsten oxide, etc.).

[0020] 2. Production of carrier oxides 2.1 Hydrothermal method A precursor salt or hydrate corresponding to one or more of the hydrogen gas-dissociating metals (cobalt, nickel, aluminum, copper, ruthenium) is dissolved in a solvent at a constant concentration (0.01 mol / L to 5 mol / L), stirred until completely dissolved, and transferred to a 100 ml polytetrafluoroethylene-lined autoclave. A certain amount of precipitant is dissolved in 50 ml of solvent and added to the above suspension to form the stock solution. The autoclave is sealed and hydrothermally treated at a constant temperature (80°C-220°C) for a period of time (1-24 hours). The obtained precursor is washed multiple times with deionized water until the pH of the washing solution becomes neutral, and then freeze-dried overnight to obtain a metal support oxide.

[0021] 2.2 Co-precipitation method A precursor salt or hydrate corresponding to one or more metals that dissociate hydrogen gas (cobalt, nickel, aluminum, copper, ruthenium) is dissolved in a solvent at a constant concentration (0.01 mol / L to 5 mol / L) and ultrasonically stirred until completely dissolved. An appropriate amount of precipitant solution is added dropwise to the precursor salt solution while vigorously stirring. After the addition is complete, stirring is continued for 4 hours, then the mixture is centrifuged three times with anhydrous ethanol, dried in an oven, polished, and calcined in a muffler furnace to obtain a metal support oxide.

[0022] 3. Synthesis of reverse catalysts 3.1 In-situ metal precursors in nanoparticle solutions at Sedimentation A precursor salt or hydrate corresponding to one or more of the hydrogen gas-dissociating metals (cobalt, nickel, aluminum, copper, ruthenium) is dissolved in a solvent at a constant concentration (0.01 mol / L to 5 mol / L) and ultrasonically stirred until completely dissolved. A constant amount of the nanooxide suspension produced in step 1 is then added dropwise to the solution in a constant molar ratio. A constant concentration of precipitant solution is added dropwise to the suspension while vigorously stirring to control the pH value to approximately 9. The resulting precipitate is aged at room temperature for a further hour, filtered, and then washed with deionized water at room temperature. The obtained material is dried in air overnight and then calcined in still air. After calcination, it is reduced in a hydrogen gas atmosphere, and the reduced nanooxide is supported on a metal solid to obtain the reverse catalyst produced.

[0023] 3.2 Soaking method The metal support oxide powder (or the metal support reduced and passivated in Step 2) produced in Step 2 is dispersed in 100 mL of anhydrous ethanol. A fixed amount of the nanooxide suspension produced in Step 1 is then added dropwise to the solution in a fixed molar ratio. The mixture is stirred for 0.5 hours, followed by sonication for 1 hour to thoroughly disperse the slurry. The slurry is then condensed under reflux at 70°C for 2 hours. The solution is then spin-dried, and the resulting precipitate is freeze-dried overnight. After freeze-drying, it is reduced in a hydrogen gas (residual nitrogen gas) atmosphere, and the reduced nanooxide is supported on a metal solid to obtain the catalyst.

[0024] 3.3 Monolithic catalyst A sheet of foamed nickel, foamed copper, or foamed cobalt, measuring 3 cm in length, 2 cm in width, and 2 mm in thickness, is ultrasonically treated for 30 minutes each with dilute hydrochloric acid (2 mol / L), ethanol, and deionized water. The treated sheet is then immersed in the hydroxide ethanol sol from step 1, uniformly stirred, and transferred to a 100 mL polytetrafluoroethylene-lined autoclave. The autoclave is then sealed and heat-treated at a constant temperature (80-200°C) for 1-12 hours. The resulting sheet of foamed metal is washed multiple times with deionized water, dried overnight in air, and then calcined in still air. After calcination, it is reduced in a hydrogen gas atmosphere, and the nanooxide obtained by reduction is supported on the sheet of foamed metal material to obtain the reverse catalyst.

[0025] In this invention, the metal loading rate is the mass percentage of the amount of metallic substance relative to the total amount of catalyst material, and the calculation formula is: Metal loading rate = Amount of metallic substance / Total amount of catalyst material × 100%. In this invention, the particle size of the solid catalyst support is 10-200 mesh (20 mesh, 30 mesh, 60 mesh, 80 mesh, 100 mesh, 150 mesh), and the carbon dioxide methane reaction is carried out in a gas-solid phase.

[0026] The molar ratio of carbon dioxide to hydrogen gas flowing at room temperature is 1:4, and the space velocity per gas hour is 9000-127000 h. -1 The reaction pressure range is from atmospheric pressure to 6 MPa, and the reaction temperature range is from 25°C to 450°C.

[0027] In one specific embodiment, the catalyst stability experiment results showed stable operation for 1500 hours, with a carbon dioxide conversion rate maintained at approximately 90%, methane selectivity at >99%, a reaction temperature of 200°C, and atmospheric pressure.

[0028] The embodiments of this application will be described in more detail below with reference to examples and comparative examples.

[0029] [Example 1] Zirconium chloride and manganese chloride were dissolved in 50 mL of water at a concentration of 0.075 mol / L and stirred until completely dissolved. Then, the zirconium chloride / manganese chloride solution was added to 50 mL of 2.5% aqueous ammonia solution and stirred for 2 hours to obtain zirconium hydroxide / manganese hydroxide sol. Finally, it was added to 20 mL of anhydrous ethanol to obtain zirconium ethoxide / manganese ethoxide sol. 5 g of zirconium ethoxide / manganese ethoxide sol was added to a mixed solution of oleic acid:oleylamine:ethanol in a ratio of 40 mL:5 mL:5 mL and stirred uniformly. This mixture was then transferred to a 100 mL polytetrafluoroethylene-lined autoclave. The autoclave was then sealed and heated at 200°C for 12 hours. The resulting precipitate was washed multiple times with deionized water until the pH of the washing solution became neutral, and then freeze-dried overnight to obtain nano-zirconium oxide / nano-manganese oxide. This precipitate was then dispersed in ethanol to obtain a transparent dispersion of nano-zirconium oxide / nano-manganese oxide.

[0030] 0.01 mol of Ni(NO3)·6H2O was dissolved in 100 mL of anhydrous ethanol. Then, a certain amount of the mixed oxide suspension of nano-zirconium oxide and nano-manganese oxide produced above was added dropwise to nickel nitrate solution in a molar ratio of Ni:Mn:Zr = 40:3:3. A suitable amount of 0.50 mol L was added while vigorously stirring (500 r). -1 A Na2CO3 solution (0.5 mol / L, 50 ml) was injected into the precursor salt solution using an injection pump (1 ml / min) to control the pH of the solution to approximately 9. The resulting precipitate was aged at room temperature for another hour, filtered, and then washed with deionized water at room temperature. The obtained material was dried overnight in air at 75°C and then calcined in still air at 400°C for 3 hours. After calcination, it was reduced at 450°C for 3 hours in a hydrogen gas atmosphere, and the resulting solid powder was the manufactured reverse catalyst, denoted as ZrMnO4 / Ni.

[0031] The solid catalyst was granulated to a particle size of 60 - 80 mesh, placed in a gas-solid reactor, and the carbon dioxide methanation reaction was carried out. The molar ratio of the flowing carbon dioxide to hydrogen gas was a reaction gas of 1:4, and the space velocity was 21,000 - 127,000 h -1 , the reaction pressure was atmospheric pressure, and the reaction temperature was 130 - 320 °C.

[0032] [Example 2] Zirconium chloride and titanium tetrachloride were dissolved in 50 mL of water at a concentration of 0.075 mol / L and stirred until completely dissolved. Then, the zirconium chloride·titanium tetrachloride solution was added to 50 mL of a 2.5% aqueous ammonia solution and stirred for 2 h to obtain a zirconium hydroxide·titanium hydroxide sol. Finally, it was added to 20 mL of absolute ethanol to obtain a zirconium ethoxide·ethanol titanium sol. 5 g of the zirconium ethoxide·ethanol titanium sol was added to a mixed solution of oleic acid:oleylamine:ethanol of 40 mL:5 mL:5 mL and stirred uniformly, and then transferred to a 100 ml autoclave lined with polytetrafluoroethylene. Then, the autoclave was sealed and heated at 200 °C for 12 h. The obtained precipitate was washed several times with deionized water until the pH of the washing solution became neutral, freeze-dried overnight to obtain nano-zirconium oxide·nano-titanium oxide, and dispersed in ethanol to obtain a transparent dispersion of nano-zirconium titanate solid solution.

[0033] 0.01 mol of Ni(NO3)6H2O was dissolved in 100 mL of absolute ethanol. And a certain amount of the mixed oxide suspension of nano-zirconium oxide·nano-titanium oxide produced above was dropped into the nickel nitrate solution at a molar ratio of Ni:Ti:Zr = 40:3:3. While stirring vigorously (500 r), an appropriate amount of 0.50 molL -1A Na2CO3 solution (0.5 mol / L, 50 ml) was injected into the precursor salt solution using an injection pump (1 ml / min) to control the pH of the solution to approximately 9. The resulting precipitate was aged at room temperature for another hour, filtered, and washed with deionized water at room temperature. The resulting material was dried overnight in air at 75°C and then calcined in still air at 400°C for 3 hours. After calcination, the material was reduced at 450°C for 3 hours in a hydrogen gas atmosphere. The solid powder obtained by reduction was the manufactured reverse catalyst, denoted as ZrTiO4 / Ni.

[0034] The solid catalyst was granulated to a particle size of 60-80 mesh and placed in the gas-solid phase to carry out the carbon dioxide methane reaction. The molar ratio of carbon dioxide to hydrogen gas flowing was 1:4, and the space velocity was 21,000 h⁻¹. -1 The reaction pressure was atmospheric pressure, and the reaction temperature was 130-320°C.

[0035] [Example 3] The results were the same as in Example 2, except that the precursor salts were nickel nitrate hexahydrate, titanium tetrachloride, and cerium chloride.

[0036] [Example 4] The results were the same as in Example 1, except that the precursor salts were nickel nitrate hexahydrate, aluminum chloride, and zirconium chloride.

[0037] [Example 5] The configuration was the same as in Example 1, except that the support precursor salts were nickel nitrate hexahydrate and aluminum nitrate notahydrate, the supported oxide precursor salts were zirconium chloride and manganese chloride, and the molar ratio of Ni / Al / Zr / Mn was 30 / 10 / 3 / 3.

[0038] [Example 6] The procedure was the same as in Example 1, except that the carrier precursor salt was cobalt nitrate hexahydrate.

[0039] [Example 7] The configuration was the same as in Example 1, except that the support precursor salts were nickel nitrate hexahydrate and cobalt nitrate hexahydrate, the supported oxide precursor salts were zirconium chloride and manganese chloride, and the molar ratio of Ni / Co / Zr / Mn was 30 / 10 / 3 / 3.

[0040] [Example 8] Zirconium chloride and manganese chloride were dissolved in 50 mL of water at a concentration of 0.075 mol / L and stirred until completely dissolved. Then, the zirconium chloride / manganese chloride solution was added to 50 mL of 2.5% aqueous ammonia solution and stirred for 2 hours to obtain a zirconium hydroxide / manganese hydroxide sol. Finally, it was added to 20 mL of anhydrous ethanol to obtain a zirconium ethoxide / manganese ethoxide sol. 5 g of the zirconium ethoxide / manganese ethoxide sol was added to a mixed solution of oleic acid:oleylamine:ethanol in a ratio of 40 mL:5 mL:5 mL and stirred uniformly. This mixture was then transferred to a 100 mL polytetrafluoroethylene-lined autoclave. The autoclave was then sealed and heated at 200 °C for 12 hours. The resulting precipitate was washed multiple times with deionized water until the pH of the washing solution became neutral, and then freeze-dried overnight to obtain nano-zirconium oxide / nano-manganese oxide. This precipitate was then dispersed in ethanol to obtain a transparent dispersion of the mixed oxide of nano-zirconium oxide / nano-manganese oxide.

[0041] 0.01 mol of Ni(NO3)·6H2O was dissolved in 100 mL of anhydrous ethanol. Then, a certain amount of the mixed oxide suspension of nano-zirconium oxide and nano-manganese oxide produced above was added dropwise to nickel nitrate solution in a molar ratio of Ni:Mn:Zr = 40:3:3. A suitable amount of 0.50 mol·L was added while vigorously stirring (500 r). -1 A Na2CO3 solution (0.5 mol / L, 50 ml) was injected into the precursor salt solution using an injection pump (1 ml / min) to control the pH of the solution to approximately 9. The resulting precipitate was aged at room temperature for another hour, filtered, and then washed with deionized water at room temperature. The resulting precipitate was dried overnight in air at 75°C.

[0042] 0.32 ml of ruthenium(III) chloride solution (13.89 mg / ml) was diluted to 15 mL with deionized water, and 1.0 g of the dried precipitate was added while vigorously stirring. The suspension was then evaporated in a 60°C water bath and dried at 110°C. The resulting solid was ZrMnO x The material was represented as / Ni-Ru and calcined in air at 400°C for 3 hours. After calcination, it was reduced in a hydrogen gas atmosphere at 450°C for 3 hours. The solid powder obtained by reduction was the reverse catalyst produced and was denoted as ZrMnO4 / Ni-Ru.

[0043] [Example 9] The configuration was the same as in Example 1, except that the support precursor salt was nickel nitrate hexahydrate, the supported metal oxide precursor salt was zirconium chloride, and the Ni / Zr molar ratio was 40 / 6.

[0044] [Example 10] The configuration was the same as in Example 1, except that the carrier precursor salt was nickel nitrate hexahydrate, the supported metal oxide precursor salt was manganese hexanitrate hydrate, and the Ni / Mn molar ratio was 40 / 6.

[0045] [Example 11] The method was the same as in Example 2, except that the support precursor salt was nickel nitrate hexahydrate, the supported oxide precursor salt was titanium tetrachloride, and the Ni / Ti molar ratio was 40 / 6.

[0046] [Example 12] The method was the same as in Example 1, except that the support precursor salt was nickel nitrate hexahydrate, the supported metal oxide precursor salt was aluminum trichlorate, and the Ni / Al molar ratio was 40 / 6.

[0047] [Example 13] Zirconium chloride and manganese chloride were dissolved in 50 mL of water at a concentration of 0.075 mol / L, and stirred until completely dissolved. Then, the zirconium chloride / manganese chloride solution was added to 50 mL of 2.5% aqueous ammonia solution and stirred for 2 hours to obtain zirconium hydroxide / manganese hydroxide sol. Finally, it was added to 20 mL of anhydrous ethanol to obtain zirconium ethoxide / manganese ethoxide sol. 5 g of zirconium ethoxide / manganese ethoxide sol was added to a mixed solution of oleic acid:oleylamine:ethanol in a ratio of 40 mL:5 mL:5 mL and stirred uniformly.

[0048] A sheet of foamed nickel (0.47 g) measuring 3 cm in length, 2 cm in width, and 2 mm in thickness was ultrasonically treated for 30 minutes with dilute hydrochloric acid (2 mol / L), ethanol, and deionized water, respectively. After treatment, the foamed nickel was immersed in the above-mentioned zirconium ethoxide (0.0006 mol) / manganese ethoxide (0.0006 mol) sol (Zr:Mn=1:1) and placed in a 100 mL polytetrafluoroethylene-lined autoclave. The autoclave was then sealed and heated at 200°C for 12 hours. The resulting foamed nickel was washed multiple times with deionized water, dried overnight in 75°C air, and then calcined in still air at 400°C for 3 hours. After calcination, it was reduced in a hydrogen gas atmosphere at 450°C for 3 hours. The resulting sheet material was the manufactured reverse catalyst and was denoted as ZrMnO4 / NF.

[0049] The solid catalyst had a particle size of 60-80 mesh and was placed in a gas-solid-phase reactor to carry out the carbon dioxide methane reaction. The molar ratio of carbon dioxide to hydrogen gas flowing through the reaction gas was 1:4, and the space velocity was 21,000 to 127,000 h⁻¹. -1 The reaction pressure was atmospheric pressure, and the reaction temperature was 180-320°C.

[0050] [Comparative Example 1] Except for the molar ratio of Ni / Zr / Mn being 40 / 1 / 9, it was the same as Example 1.

[0051] [Comparative Example 2] Except for the molar ratio of Ni / Zr / Mn being 40 / 9 / 1, it was the same as Example 1.

[0052] [Comparative Example 3] Except for the molar ratio of Ni / Zr / Mn being 6 / 20 / 20, it was the same as Example 1.

[0053] [Comparative Example 4] Except for the Ni / Mn molar ratio being 6 / 40, it was the same as Example 1.

[0054] [Comparative Example 5] Except for the Ni / Zr molar ratio being 6 / 40, it was the same as Example 1.

[0055] [Comparative Example 6] The procedure was the same as in Example 1, except that the precipitating agent was ammonium carbonate.

[0056] [Comparative Example 7] Precipitant Oxalic acid Except for being ammonium, it was the same as in Example 1.

[0057] [Comparative Example 8] The procedure was the same as in Example 1, except that the precipitant was aqueous ammonia.

[0058] [Comparative Example 9] The procedure was the same as in Example 1, except that the precipitating agent was sodium hydroxide.

[0059] [Comparative Example 10] Zirconium chloride and manganese chloride were dissolved in 50 mL of water at a concentration of 0.075 mol / L and stirred until completely dissolved. Then, the zirconium chloride / manganese chloride solution was added to 50 mL of 2.5% aqueous ammonia solution and stirred for 2 hours to obtain a zirconium hydroxide / manganese hydroxide sol. Finally, it was added to 20 mL of anhydrous ethanol to obtain a zirconium ethoxide / manganese ethoxide sol. 5 g of the zirconium ethoxide / manganese ethoxide sol was added to a mixed solution of oleic acid:oleylamine:ethanol in a ratio of 40 mL:5 mL:5 mL and stirred uniformly. This mixture was then transferred to a 100 mL polytetrafluoroethylene-lined autoclave. The autoclave was then sealed and heated at 200 °C for 12 hours. The resulting precipitate was washed multiple times with deionized water until the pH of the washing solution became neutral, and then freeze-dried overnight to obtain a mixed oxide of nano-zirconium oxide and nano-manganese oxide. This mixture was then dispersed in ethanol to obtain a transparent dispersion of the mixed oxide of nano-zirconium oxide and nano-manganese oxide.

[0060] 1 g of P123 was dissolved in 50 ml of deionized water and transferred to a 50 ml polytetrafluoroethylene-lined autoclave. Then, 0.9 g of nickel nitrate hexahydrate, 0.9 g of urea, and 25 ml of deionized water were added to the suspension to form the stock solution. The autoclave was then sealed and heated at 140°C for 12 hours. The precipitate was collected by centrifugation, washed with deionized water and ethanol, and freeze-dried overnight. The resulting solid was heated in a tubular furnace at 400°C for 3 hours to obtain NiO powder.

[0061] 0.01 mol of nickel oxide powder was dispersed in 100 mL of anhydrous ethanol and added to a round-bottom flask. A fixed amount of the mixed oxide suspension of nano-zirconium oxide and nano-manganese oxide produced above was then added dropwise to the round-bottom flask in a molar ratio of Ni:Mn:Zr = 40:3:3. The mixture was stirred for 0.5 hours and then sonicated for 1 hour to thoroughly disperse the slurry. The slurry was then condensed under reflux at 70°C for 2 hours. The flask was transferred to a rotary evaporator, heated to 60°C, and the rotation speed was controlled to 200 r / min to rotary-dry the solution. The resulting precipitate was freeze-dried overnight.

[0062] After freeze-drying, the catalyst was reduced in a hydrogen gas atmosphere at 400°C for 2 hours. The resulting solid powder (ZrMnO4 / Ni) was the catalyst to be produced. The particle size of the solid catalyst was 60-80 mesh, and the carbon dioxide methane reaction was carried out in the gas-solid phase. The molar ratio of the flowing carbon dioxide to hydrogen gas was 1:4, and the space velocity was 21,000 h⁻¹. -1 The reaction pressure was atmospheric pressure, and the reaction temperature was 150-300°C.

[0063] [Comparative Example 11] Except for the carrier precursor salt being nickel nitrate hexahydrate, the supported metal oxide precursor salt being manganese chloride, and the Ni / Mn molar ratio being 40 / 6, it was the same as Comparative Example 10.

[0064] [Comparative Example 12] Except for the fact that the carrier precursor salt was nickel nitrate hexahydrate, the supported metal oxide precursor salt was zirconium chloride, and the Ni / Zr molar ratio was 40 / 6, it was the same as Comparative Example 10.

[0065] [Comparative Example 13] The configuration was the same as in Example 1, except that the support precursor salt was cobalt nitrate hexahydrate, the supported metal oxide precursor salts were zirconium chloride and manganese chloride, and the molar ratio of Co / Zr / Mn was 6 / 20 / 20.

[0066] [Comparative Example 14] The configuration was the same as in Example 2, except that the support precursor salt was nickel nitrate hexahydrate, the supported metal oxide precursor salt was tetrabutyl titanate, and the Ni / Ti molar ratio was 6 / 40.

[0067] [Comparative Example 15] The method was the same as in Example 1, except that the support precursor salt was nickel nitrate hexahydrate, the supported metal oxide precursor salt was aluminum chloride, and the Ni / Al molar ratio was 6 / 40.

[0068] [Comparative Example 16] The method was the same as in Example 1, except that the carrier precursor salt was nickel nitrate hexahydrate, the supported metal oxide precursor salt was magnesium chloride, and the Ni / Mg molar ratio was 6 / 40.

[0069] [Comparative Example 17] Glucose (0.01 mol) and acrylamide (0.015 mol) were stirred and then dissolved in deionized water (80 mL). Cerium nitrate hexahydrate (0.0045 mol) and lanthanum nitrate hexahydrate (0.0005 mol) were added to form a clear solution. Then, 3.2 mL of 25 wt% ammonia solution was added dropwise while stirring to control the pH to approximately 10. After stirring for 5 hours, the solution was transferred to a 100 mL polytetrafluoroethylene-lined autoclave. The autoclave was hydrothermally treated at 180 °C for 72 hours, and after cooling to room temperature, the solid precipitate was collected by filtration and washed several times with deionized water and anhydrous ethanol. It was dried at 100 °C for 10 hours and then heated at 600 °C min at a heating rate of 5 °C min. -1 It was fired for 2 hours to obtain La-CeO2-600.

[0070] Nickel nitrate hexahydrate (0.165 g) is dissolved in a certain amount of ethylene glycol (0.2 mL), and the above solution is added dropwise to the prepared carrier (0.3 g), sealed and left at 40°C for 24 hours, dried at 100°C for 12 hours, and then left in air at 5°C min. -1 The mixture was fired at 400°C for 2 hours at the specified heating rate. After firing, it was reduced in a hydrogen gas atmosphere at 400°C for 2 hours, and the Ni / La-CeO2 obtained by reduction was used as the catalyst to be produced. [1] That was the case.

[0071] [Comparative Example 18] A certain amount of nickel nitrate hexahydrate and ruthenium(III) nitrosylnitrate solution are mixed in 40 mL of deionized water, and a certain amount of Ce 0.5 Zr 0.5 It was added to O2 (commercial), and the suspension was evaporated in a water bath at 50°C and then dried at 110°C. The resulting solid was Ni-Ru / CeZrO xIt is expressed as follows, and is calcined in air at 400°C for 3 hours, and after calcination, is reduced in a hydrogen gas atmosphere at 400°C for 2 hours to obtain the Ni-Ru / Ce 0.5 Zr 0.5 O2 is the catalyst that is manufactured. [2] That was the case.

[0072] [Comparative Example 19] A certain amount of nickel nitrate hexahydrate and ruthenium(III) nitrosylnitrate solution are mixed in 40 mL of deionized water, and a certain amount of Ce 0.5 Al 0.5 It was added to O2 (commercial), and the suspension was evaporated and dried in a 50°C water bath, and then dried at 110°C. The resulting solid was calcined in air at 400°C for 3 hours. After calcination, it was reduced in a hydrogen gas atmosphere at 400°C for 2 hours to obtain the Ni-Ru / Ce 0.5 Al 0.5 O2 is the catalyst that is manufactured. [2] That was the case.

[0073] [Comparative Example 20] Nickel nitrate hexahydrate (0.297 g) and manganese acetate tetrahydrate (0.501 g) were dissolved in 6 mL of deionized water. An appropriate amount of TiO2 (approximately 2 g) was slowly added to the aqueous solution while stirring at room temperature. The suspension was left to stand for 3 hours, and then heated to 80°C to remove the excess H2O. The final solid was dried overnight in a still air oven at 110°C, and the resulting Ni-Mn / TiO2 was the catalyst to be produced. [3] That was the case.

[0074] [Comparative Example 21] Nickel nitrate hexahydrate (0.44 g, 1.50 mmol), aluminum nitrate nonahydrate (0.19 g, 0.50 mmol), zirconium nitrate pentahydrate (0.02 g, 0.005 mmol), and urea (0.60 g, 10.00 mmol) were dissolved in deionized water (70 mL). The mixed solution was then placed in a Teflon-lined autoclave and subjected to a hydrothermal reaction at 120 °C for 12 hours. The solid product was obtained by centrifugation, washed with deionized water and ethanol until the pH of the solution approached 7, and dried at 80 °C for 15 hours. 0.73 Zr0.03 Al 0.24 - It was named LDH. The obtained Ni 0.73 Zr 0.03 Al 0.24 -LDH was reduced in H2 gas at 600°C for 2 hours (heating rate 5°C / min). -1 , H2 flow rate 50mLmin -1 ) The catalyst that is manufactured afterwards [4] I obtained it.

[0075] [Comparative Example 22] A 5cm long, 2cm diameter treated cylindrical foamed nickel was immersed in a solution containing nickel nitrate hexahydrate (0.009 mol), aluminum nitrate nonahydrate (0.0015 mol), iron nitrate (0.0015 mol), and urea (0.04 mol), stirred for 30 minutes, and then transferred to a 100 mL polytetrafluoroethylene-lined autoclave. The autoclave was then sealed and heated at 110°C for 8 hours. The resulting precursor was washed multiple times with deionized water and dried in air at 65°C for 12 hours. Finally, the precursor was subjected to in-situ heating in a tubular furnace at 500°C at a heating rate of 2°C / min in a flowing H2 / N2 atmosphere (1 / 10, V / V). in The Ni-Fe-Al / NF obtained by reduction is the catalyst produced. [5] That was the case.

[0076] [Comparative Example 23] Cerium nitrate hexahydrate and chromium nitrate nonahydrate were dissolved in 30 mL of deionized water, resulting in a Cr / Ce molar ratio of 1:9. Aqueous ammonia solution was added dropwise to the precursor salt solution while continuously stirring until complete precipitation occurred at pH=10. The mixture was filtered to collect the precipitate, which was repeatedly washed with deionized water. The solid was dried overnight at 110°C and calcined at 500°C for 4 hours to obtain a Cr-CeO2 support.

[0077] Cr-CeO2 was immersed in an aqueous solution of RuCl3·3H2O. The mixture was evaporated in a 70°C water bath for 4 hours with vigorous stirring, and then dried overnight at 110°C. The resulting solid was named RuO2 / Cr-CeO2 and was calcined in air at 500°C for 4 hours. After calcination, it was reduced in a hydrogen gas atmosphere at 400°C for 2 hours. The resulting Ru / Cr-CeO2 is the catalyst to be produced. [6] That was the case.

[0078] [Comparative Example 24] Ru-TiO2: 0.6 g of ruthenium(III) chloride hydrate was diluted in 50 mL of deionized water, and 2.0 g of anatase-type titanium dioxide was added while vigorously stirring. The suspension was evaporated in a water bath at 50°C and then dried at 110°C. The resulting solid, represented as Ru / TiO2, was calcined in air at 400°C for 3 hours. The sample was repeatedly washed with dilute ammonia solution to remove residual chloride, and the sample was dried overnight at 60°C. The resulting Ru / TiO2 was the catalyst to be produced. The Ru loading in the Ru / TiO2 catalyst was 10 wt%.

[0079] [Comparative Example 25] Commercial Ru / Al2O3 The procedure was the same as in Example 1, except that Ru-TiO2 and commercial Ru-Al2O3 were used, and the reduction temperature was 200°C.

[0080] Table 1 shows the CO2 conversion rate when each catalyst is used in the CO2 methane reaction.

[0081] [Table 1A] [Table 1B]

[0082] Compared to the comparative example, Examples 1 to 13 in Table 1 are lowThis catalyst exhibits CO2 methanation activity at warm temperatures and demonstrates superior performance in CO2 methanation reactions at low temperatures compared to conventional forward-direction metal / oxide catalysts, using a reverse-direction oxide / metal catalyst.

[0083] Figure 1 shows the thermodynamic diagram of the temperature-dependent changes in the CO2 methane reaction and its side reaction, the reverse water vapor shift reaction. The methane reaction is a strongly exothermic reaction, and low temperatures are favorable for the reaction, while the reverse water-gas shift reaction is an endothermic reaction, and high temperatures are favorable for the production of CO.

[0084] Figure 2 shows a comparison of the reaction results in the 130-320°C range for Examples 1, 9, and 10 and Comparative Examples 1, 2, 3, 24, and 25. As can be seen from the above, the reverse ZrMnO x The Ni catalyst exhibits excellent performance at 170-180°C and lasts for 21,000 hours. -1 It achieves CO2 conversion performance close to the equilibrium conversion rate at space velocity, and the selectivity for the target product, methane, is >99.9%, significantly exceeding the performance of commercial Ru / Al2O3 and Ru / TiO2 catalysts. Ni is ZrMnO x For forward-directed catalysts supported in oxide solid solutions, temperatures above 260°C are required to achieve a CO2 conversion rate of 50% or more.

[0085] Figure 3 shows the results of Example 1 at 190°C for 21,000-127,000 hours. -1 The results of the methanation activity in the spatial velocity range are shown, and as can be seen from this, even at high spatial velocities, the reverse ZrMnO x The Ni catalyst still maintained a high CO2 conversion rate and near 100% methane selectivity.

[0086] Figure 4 shows the stability test results for Example 1 at 180°C over a range of 1500 hours. After 1500 hours of operation, the catalytic activity did not change significantly.

[0087] Figure 5 shows the reaction results for Example 1 and Comparative Examples 6, 7, 8, and 9, with different precipitants: sodium carbonate, aqueous ammonia, and ammonium carbonate. Oxalic acidComparing ammonium and sodium hydroxide, both can produce high-performance reverse methanation catalysts at low temperatures, but the effect is greatest when sodium carbonate is used as a precipitant.

[0088] Figure 6 shows the reaction results for Examples 1, 6, and 7 and Comparative Example 13 in the 130-220°C range, and reverse ZrMnO x Compared to the Ni catalyst, cobalt doping results in a certain degree of decrease in activity, and Co is replaced by ZrMnO x The activity of the forward-directed catalyst supported on the oxide solid solution was significantly lower than that of the reverse-directed catalyst.

[0089] Table 1 shows the comparison results between Examples 1, 9, 10, and 13 and Comparative Examples 10, 11, and 12. Soaking method Both the deposition and sedimentation method and the production method involving immersing oxide nanoparticle precursor salts in a porous monolithic catalyst can synthesize reverse methanation catalysts with excellent performance.

[0090] Figure 7 shows the reaction results for Examples 9-10 and Comparative Examples 4-5. As can be seen, the binary reverse catalyst also exhibits superior reaction performance compared to conventional forward catalysts, consistent with the trend of the ternary reverse catalyst.

[0091] Figure 8 is a HAADF-STEM image of the catalyst produced in Example 1, showing that the particle size of the catalyst metal support produced in the present invention is about 10 nm, and that the oxide is uniformly dispersed on the metal support.

[0092] The foregoing are merely preferred embodiments of the present application and are not intended to limit it. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present application should be included within the scope of the protections of the present application.

[0093] References [1] Zhang T, Wang W, Gu F, et al. Enhancing the low-temperature CO2methanation over Ni / La-CeO2catalyst: The effects of surface oxygen vacancy and basic site on the catalytic performance[J]. Applied Catalysis B: Environmental, 2022, 312: 121385. [2] Merkouri L P, Le Sache E, Pastor-Perez L, et al. Versatile Ni-Ru catalysts for gas phase CO2conversion: Bringing closer dry reforming, reverse water gas shift and methanation to enable end-products flexibility[J]. Fuel, 2022, 315: 123097. [3] Vrijburg W L, Moioli E, Chen W, et al. Efficient base-metal NiMn / TiO2catalyst for CO2methanation[J]. Acs Catalysis, 2019, 9(9): 7823-7839. [4] He F, Zhuang J, Lu B, et al. Ni-based catalysts derived from Ni-Zr-Al ternary hydrotalcites show outstanding catalytic properties for low-temperature CO2methanation[J]. Applied Catalysis B: Environmental, 2021, 293: 120218. [5] Gao Y, Dou L, Zhang S, et al. Coupling bimetallic Ni-Fe catalysts and nanosecond pulsed plasma for synergistic low-temperature CO2methanation[J]. Chemical Engineering Journal, 2021, 420: 127693. [6] Xu X, Liu L, Tong Y, et al. Facile Cr 3+ -doping strategy dramatically promoting Ru / CeO2for low-temperature CO2methanation: Unraveling the roles of surface oxygen vacancies and hydroxyl groups[J]. ACS Catalysis, 2021, 11(9): 5762-5775.

[0094] (Note) (Note 1) A solid reverse-direction catalyst comprising a metal support that dissociates hydrogen gas, a nanooxide supporting phase that generates oxygen vacancies and adsorbs activated carbon dioxide, the nanooxide uniformly dispersed on the surface of the metal support, and having a nanooxide / metal reverse-direction interface structure, The carrier metal is one or more selected from cobalt, nickel, aluminum, copper, and ruthenium. The supported phase nanooxide is one or more selected from titanium oxide, aluminum oxide, manganese oxide, cerium oxide, zirconium oxide, silicon oxide, and tungsten oxide. A solid reverse catalyst characterized in that the mole fraction of the supported phase metal is 0.01 to 30% of the total molar amount of metal in the carrier and supported phase.

[0095] (Note 2) A method for producing a solid reverse-direction catalyst as described in Appendix 1, The aforementioned manufacturing method is A carrier precursor is produced by hydrothermal or coprecipitation methods under the conditions of a precipitant and solvent. To produce a nanooxide dispersion under the conditions of a precipitant, solvent, and protective agent by the sol method, Precipitation method or Soaking method A method for producing a solid reverse-direction catalyst, comprising the steps of: in situ depositing and precipitating or immersing nanooxides on a support precursor using the method described above; calcining and reducing the resulting powdered solid; and then uniformly dispersing the nanooxides on the surface of a metal support to obtain a solid reverse-direction catalyst.

[0096] (Note 3) This includes the following steps (1) and (2): (1) In the synthesis of nanooxides, The precursor salt of the supported phase is dissolved in a solvent, the resulting solution is added to a precipitating agent solution to obtain a hydroxide sol, the obtained hydroxide sol is added to ethanol to obtain a hydroxide-ethanol sol, the hydroxide-ethanol sol is dispersed in a mixed solution of oleic acid / oleylamine / ethanol, stirred uniformly, transferred to an autoclave, sealed, and subjected to solvent heat treatment at 80-220°C for 1-24 hours, after which the solid product is collected, washed with deionized water to neutralize the pH of the washing solution, freeze-dried to obtain nanooxides, and dispersed in ethanol to obtain a nanooxide dispersion. The precursor salt of the supported phase is one or more selected from titanium tetrachloride, tetrabutyl titanate, aluminum nitrate, aluminum nitrate hydrate, aluminum chloride, manganese nitrate, manganese nitrate hydrate, manganese chloride, cerium nitrate, cerium nitrate hydrate, cerium chloride, zirconium nitrate, zirconium nitrate hydrate, zirconium chloride, tetraethyl orthosilicate, ammonium metatungstate, sodium tungstate, and tungsten chloride. (2) In the synthesis of solid reverse catalysts, The precursor salt of the support is dissolved in a solvent, the nanooxide dispersion produced in step (1) is added dropwise to the resulting solution, and the precipitant solution is added dropwise while stirring to control the pH to =9, then aged at room temperature, filtered, washed, dried, calcined in still air, and after calcination, reduced in a hydrogen gas atmosphere to produce a solid reverse catalyst. The method for producing a solid reverse catalyst according to Appendix 2, characterized in that the precursor salt of the support is one or more selected from cobalt nitrate, cobalt nitrate hydrate, cobalt chloride, nickel nitrate, nickel nitrate hydrate, nickel chloride, copper nitrate, copper nitrate hydrate, cupric chloride, and ruthenium chloride.

[0097] (Note 4) A method for producing a solid reverse-direction catalyst according to Appendix 3, characterized in that in step (1) or step (2), the solvent is one or more selected from water, methanol, ethanol, butanol, tetrahydrofuran, and methyl t-butyl ether.

[0098] (Note 5) In step (1) or step (2), the precipitating agent is ammonium carbonate, aqueous ammonia, urea, sodium hydroxide, sodium bicarbonate, Oxalic acid Ammonium, Oxalic acid A method for producing a solid reverse catalyst according to Appendix 3, characterized in that it is one or more selected from the following.

[0099] (Note 6) The method for producing a solid reverse-direction catalyst as described in Appendix 3, characterized in that in step (2), the firing temperature is 200 to 600°C and the firing time is 1 to 12 hours.

[0100] (Note 7) The method for producing a solid reverse catalyst as described in Appendix 3, characterized in that in step (2), the reduction temperature is 200 to 700°C, the time is 1 to 6 hours, the hydrogen gas concentration range in the reducing atmosphere is 5 to 100%, and the total flow rate range is 5 to 100 ml / min.

[0101] (Note 8) Applications of the solid reverse catalyst described in Appendix 1 in the carbon dioxide methanation reaction.

[0102] (Note 9) The method of the aforementioned use is: This involves placing a solid reverse catalyst in a fixed-bed reactor, with a molar ratio of carbon dioxide to hydrogen gas flowing in the reaction gases of 1:4, and a space velocity of 9,000 to 127,000 h⁻¹ per gas hour. -1 The application described in Appendix 8 is characterized in that the reaction pressure range is atmospheric pressure to 6 MPa and the reaction temperature range is 25 to 450°C.

Claims

1. A solid reverse-direction catalyst comprising a metal support that dissociates hydrogen gas, a nanooxide supporting phase that generates oxygen vacancies and adsorbs activated carbon dioxide, the nanooxide uniformly dispersed on the surface of the metal support, and having a nanooxide / metal reverse-direction interface structure, The carrier metal is nickel or an alloy thereof. The supported phase nanooxides are manganese oxide and zirconium oxide. A solid reverse catalyst characterized in that the mole fraction of the supported phase metal is 0.01 to 30% of the total molar amount of metal in the carrier and supported phase.

2. The following steps (1) and (2) are included: (1) In the synthesis of nanooxides, The precursor salt of the supported phase is dissolved in a solvent, the resulting solution is placed in a precipitating agent solution to obtain a hydroxide sol, the obtained hydroxide sol is placed in ethanol to obtain a hydroxide-ethanol sol, the hydroxide-ethanol sol is dispersed in a mixed solution of oleic acid / oleylamine / ethanol, stirred uniformly, transferred to an autoclave, sealed, and subjected to solvent heat treatment at 80-220°C for 1-24 hours, after which the solid product is collected, washed with deionized water to neutralize the pH of the washing solution, freeze-dried to obtain nanooxides, and the nanooxides are dispersed in ethanol to obtain a nanooxide dispersion. The precursor salt of the supported phase is one or more selected from manganese nitrate, manganese nitrate hydrate, and manganese chloride, and one or more selected from zirconium nitrate, zirconium nitrate hydrate, and zirconium chloride. (2) In the synthesis of solid reverse catalysts, The precursor salt of the support is dissolved in a solvent, the nanooxide dispersion produced in step (1) is added dropwise to the resulting solution, and the precipitating agent solution is added dropwise while stirring to control the pH to =9, then aged at room temperature, filtered, washed, dried, calcined in still air, reduced in a hydrogen gas atmosphere after calcination, and after the reduction, the nanooxide is uniformly dispersed on the surface of the metal support to produce a solid reverse catalyst. The method for producing a solid reverse catalyst according to claim 1, characterized in that the precursor salt of the carrier is one or more selected from cobalt nitrate, cobalt nitrate hydrate, cobalt chloride, nickel nitrate, nickel nitrate hydrate, and nickel chloride, and contains at least one of the nickel nitrate, nickel nitrate hydrate, or nickel chloride.

3. The method for producing a solid reverse catalyst according to claim 2, characterized in that in step (1) or step (2), the solvent is one or more selected from water, methanol, ethanol, butanol, tetrahydrofuran, and methyl t-butyl ether.

4. The method for producing a solid reverse catalyst according to claim 2, characterized in that in step (1) or step (2), the precipitating agent is one or more selected from ammonium carbonate, aqueous ammonia, urea, sodium hydroxide, sodium bicarbonate, ammonium oxalate, and oxalic acid.

5. The method for producing a solid reverse-direction catalyst according to claim 2, characterized in that in step (2), the firing temperature is 200 to 600°C and the firing time is 1 to 12 hours.

6. The method for producing a solid reverse catalyst according to claim 2, characterized in that in step (2), the reduction temperature is 200 to 700°C, the time is 1 to 6 hours, the hydrogen gas concentration range in the reducing atmosphere is 5 to 100%, and the total flow rate range is 5 to 100 ml / min.

7. Use of the solid reverse catalyst according to claim 1 in the carbon dioxide methanation reaction.

8. The aforementioned method of use is This involves placing a solid reverse catalyst in a fixed-bed reactor, with a molar ratio of carbon dioxide to hydrogen gas flowing in the reaction gases being 1:4, and a space velocity of 9,000 to 127,000 h⁻¹ per gas hour. －１ The use according to claim 7, characterized in that the reaction pressure range is normal pressure to 6 MPa and the reaction temperature range is 25 to 450°C.

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