Solid reverse-flow catalyst and its method of preparation and use in carbon dioxide methanation at low temperatures - Patents.com

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] The present invention relates to a solid reverse-flow catalyst and a method for its preparation and use in the multiphase catalytic reaction of hydromethanation of carbon dioxide. [Background technology]

[0002] Humankind's excessive extraction and use of fossil fuels has resulted in large amounts of CO 2 This has led to a series of serious environmental problems, such as climate change, rising sea levels, glacial retreat, thawing permafrost, and a decline in plant and animal diversity. 2 Capturing CO and converting it into methane, methanol or other high-value chemicals is a compatible solution to both environmental pollution and energy shortages. 2 Methanation is a method for energy conversion and H 2 It has great potential for energy storage applications.

[0003] [ka] CO 2 The methanation reaction (Equation 1) has a thermodynamic enthalpy change of -165.1 kJmol -1 Since this reaction is highly exothermic, the reaction process is thermodynamically favored at low temperatures. However, CO 2 From CH 4 The reduction of 1,2-dichlorophenyl ether to 1,2-dichlorophenyl ether involves the transfer of eight electrons, and a high kinetic barrier exists for the hydrogenation process, which usually results in a satisfactory CH 4 To obtain a high space-time yield, a high operating temperature (>300°C) is required. However, too high a reaction temperature can cause the CO 2 Not only does it suppress methanation, but it also favors the occurrence of the side reaction, the reverse steam shift reaction (Equation 2), and the generated by-product CO is converted into CH for subsequent energy utilization. 4 requires further separation and purification steps, and CH4 as fuel 4 Increase the cost of using CO 2 This weakens the application advantages of methanation. Therefore,2 The design and development of methanation catalysts is 2 This will effectively promote the practical application of methanation and enhance competitiveness.

[0004] Conventional low temperature CO 2 The design of hydrogenation to produce methane catalysts mainly revolves around metal / oxide supported catalysts formed from metal nanoparticles and oxide bases. At the interface of traditional metal / oxide catalysts, oxygen-containing intermediates partially adsorbed on oxide sites usually have extremely high thermodynamic stability, high hydrogenation conversion energy barriers, and are easy to occupy active centers, greatly reducing the low-temperature activity of the catalyst. The reverse oxide / metal catalysts formed by oxide clusters supported on metal supports have an interface spatial structure different from traditional metal / oxides, which has the potential to improve the conversion rate of oxygen-containing intermediates and even change the reaction pathway and improve the catalytic performance. In practical applications, the cost of some metals (e.g., iron, cobalt, nickel, copper, etc.) is almost flat or even lower than that of oxides. Therefore, the design of reverse oxide / metal structures is a promising way to achieve high-efficiency CO 2 It can provide new opportunities for the production of hydrogenation catalysts.

[0005] The present invention provides a solid reverse catalyst in which oxide nanoparticles are supported on a metal carrier, and a method for producing the same. The reverse catalyst can be used under low temperature conditions of 200°C or less and at a high reaction space velocity (127,000 h -1 ) exceeds that of most previously reported catalysts. 2 It has methanation activity, the selectivity for methane is >99%, and the methane production rate is >50 g / ml. CH4 / g cat / h, and the reverse catalyst has excellent stability even after a long operation of 1500 h. Summary of the Invention [Problem to be solved by the invention]

[0006] The object of the present invention is to provide a solid reverse flow catalyst and a method for producing the same, which has high conversion, high selectivity and high stability at low temperature. 2 The methanation process can be realized. [Means for solving the problem]

[0007] The technical solution of the present invention is as follows:

[0008] A solid reverse catalyst, comprising a metal that dissociates hydrogen gas as a carrier, a nano-oxide that generates oxygen vacancies and adsorbs activated carbon dioxide as a carrier phase, the nano-oxide being uniformly dispersed on the surface of the metal carrier, and having a nano-oxide / metal reverse interface structure; The support metal is one or more selected from cobalt, nickel, aluminum, copper, and ruthenium; The support 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% based on the total molar amount of the metal in the support and the supported phase.

[0009] The method for preparing the solid reverse catalyst according to the present invention includes the steps of preparing a carrier precursor by hydrothermal method, co-precipitation method under the conditions of suitable precipitant and solvent, preparing a nano-oxide dispersion by sol method under the conditions of suitable precipitant, solvent and protective agent, depositing and precipitating or immersing the nano-oxide on the carrier precursor in situ by means of in situ precipitation, excess immersion and other methods, calcining and reducing the obtained powdery solid, and then dispersing the minor nano-oxide uniformly on the metal carrier surface to obtain a solid reverse catalyst.

[0010] Advantageously, the method for preparing the solid inverse catalyst according to the present invention comprises the steps of: The method includes the following steps (1) and (2), (1) In the synthesis of nano-oxides, The precursor salt of the support phase is dissolved in a solvent, the resulting solution (concentration 0.01-5 mol / L) is put into a precipitant solution (concentration 0.01-5 mol / L) to obtain a hydroxide sol, the resulting hydroxide sol is put into ethanol to obtain a hydroxide-ethanol sol, and the hydroxide-ethanol sol is dispersed in a mixed solution of oleic acid / oleylamine / ethanol, stirred uniformly, transferred to an autoclave, sealed, and solvent heat-treated at 80-220°C for 1-24h, after which the solid product is collected, washed with deionized water until the pH of the washing solution becomes neutral, freeze-dried, and obtained nano-oxide, which is dispersed in ethanol to obtain a nano-oxide 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, tungsten chloride; the solvent is one or more selected from water, methanol, ethanol, butanol, tetrahydrofuran, methyl t-butyl ether; The precipitating agent is one or more selected from ammonium carbonate, aqueous ammonia, urea, sodium hydroxide, sodium bicarbonate, ammonium valerate, and valeric acid; (2) In the synthesis of solid reverse catalysts (in situ precipitation method), Dissolve the precursor salt of the carrier in a solvent, add the nano oxide dispersion (concentration: 0.01-5 mol / L) prepared in step (1) dropwise to the obtained solution (concentration: 0.01-5 mol / L), and then add the precipitant solution dropwise while stirring, control the pH to 9, and then age at room temperature, filter, wash, dry, and calcinate in still air. After calcination, reduce in a hydrogen gas atmosphere to prepare a solid reverse catalyst; In step (2), 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; the solvent is one or more selected from water, methanol, ethanol, butanol, tetrahydrofuran, methyl t-butyl ether; The precipitating agent is one or more selected from ammonium carbonate, aqueous ammonia, urea, sodium hydroxide, sodium bicarbonate, ammonium valerate, and valeric acid; The preferred aging time is 1 to 24 hours. The preferred drying temperature is 40 to 200°C, and the preferred drying time is 1 to 24 hours. The preferred firing temperature is 200 to 600°C, and the preferred firing time is 1 to 12 hours. The preferred reduction temperature is 200 to 700°C, the preferred reduction time is 1 to 6 hours, the preferred hydrogen gas concentration range in the reduction atmosphere is 5 to 100%, and the preferred total flow rate range is 5 to 100 ml / min. The particle size of the solid reverse flow catalyst produced is 10-200 mesh.

[0011] The solid reverse catalyst described in the present invention can be applied to the carbon dioxide methanation reaction. The specific application method is as follows: The solid reverse flow catalyst is placed in a fixed bed reactor. The molar ratio of the flowing carbon dioxide and hydrogen gas is 1:4. The gas hourly space velocity is 9000-127000 h -1 The reaction pressure range is from normal pressure to 6 MPa, and the reaction temperature range is from 25 to 450°C. The catalyst stability test results showed that the catalyst was operated stably for 1500 hours, the carbon dioxide conversion rate was maintained at about 90%, the methane selectivity was >99%, and the suitable reaction temperature was 200°C and the pressure was normal pressure. Effect of the Invention

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

[0013] The oxide / metal reverse catalyst prepared in the present invention can catalyze the carbon dioxide methanation reaction at low temperatures not exceeding 200°C and normal pressure conditions with high conversion, high selectivity and high stability, and the carbon dioxide conversion rate is greater than 80% and the methane selectivity is >99% under high space velocity conditions. Conventional metal / oxide catalysts all require temperature and pressure conditions of 250°C or higher to achieve the activity of the present invention. In addition, the solid reverse catalyst prepared in the present invention has good stability in the carbon dioxide hydrogenation reaction system and can be used for a long time or cycled multiple times. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a thermodynamic diagram of the change with temperature of the CO2 methanation reaction and the side reaction, the reverse steam shift reaction. [Diagram 2] 4 shows reaction results of a catalyst at different temperatures in one embodiment. [Diagram 3] 1 is a reaction result of a catalyst in one embodiment at different gas hourly space velocities. [Figure 4] 4 shows the test results of the CO2 conversion and CH4 selectivity of a catalyst in one embodiment within 1500 hours. [Diagram 5] 1 is a study of the effect of different precipitants on the methanation activity of a reverse catalyst in one embodiment. [Figure 6] 1 is a comparison of the methanation activity of metal oxide cluster catalysts supported on different metal supports in one embodiment. [Figure 7] 1 is a comparison result of methanation activity of a dual backward-flow catalyst and a conventional forward-flow catalyst according to one embodiment. [Figure 8] 1 is a HAADF-STEM photograph of the catalyst produced in Example 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] In order to more clearly understand the objectives, technical solutions and advantages of the present application, the present application will be described in more detail below with reference to the drawings and embodiments. Obviously, the described embodiments are only some of the embodiments of the present application, but not all of the embodiments. Based on the embodiments of the present application, all other technical solutions obtained by those skilled in the art belong to the scope of protection of the present application.

[0016] Conventional methanation catalysts are usually manufactured by methods such as impregnation and liquid phase reduction, and in catalysts manufactured by such methods, after calcination and reduction steps, the minor metal components are dispersed in the form of nanoparticles on the oxide support to further form a metal / oxide interface structure. Conventional carbon dioxide methanation catalysts usually use oxides such as cerium oxide, zirconium oxide, aluminum oxide, silicon oxide, titanium oxide, etc., with a molar fraction of about 50% to 99.9% in the catalyst as the support phase, and provide oxygen vacancies to dissociate carbon dioxide. Metals such as iron, cobalt, nickel, copper, ruthenium, rhodium, palladium, platinum, etc., for dissociating hydrogen gas, with a molar fraction of about 0.01% to 30% in the catalyst, are used as the catalyst support phase. Conventional forward catalysts often require temperatures of 250°C or higher to catalyze the methanation reaction, and the active centers of the supported nanoparticles are prone to agglomeration and deactivation in strongly exothermic reaction systems. The highly unsaturated coordination of the nanoparticles also tends to cause catalyst deposits and deactivation.

[0017] In the present invention, the reverse catalyst obtained by using a metal that dissociates hydrogen gas as a support phase and an oxide that generates oxygen vacancies and adsorbs activated carbon dioxide as a support phase can realize the carbon dioxide methanation process at a high space velocity of 200°C or less with high activity and high selectivity, and has high-temperature cycle stability at 450°C. By using a metal in the continuous phase as a support, surface coordination unsaturation is reduced and the formation of deposits is suppressed. In one specific embodiment, the gas hourly space velocity is 9,000 to 127,000 h -1 The conversion rate of carbon dioxide is >80%, the selectivity of methane is >99%, and the stability is more than 1500h. The specific synthesis method is as follows:

[0018] 1. Synthesis of Nano-Oxides A precursor salt or hydrate corresponding to one or more metals that generate oxygen vacancies and adsorb activated carbon dioxide is dissolved in a solvent at a certain concentration (0.01 mol / L-5 mol / L), stirred until completely dissolved, then placed in a precipitant solution to obtain a hydroxide sol, and the resulting sol is placed in ethanol to obtain a hydroxide-ethanol sol. A certain amount of hydroxide sol is dispersed in a mixed solution of oleic acid:oleylamine: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 certain temperature (80°C-220°C) for a period of time (1-24 h). The resulting precursor is washed multiple times with deionized water until the pH of the washing solution is neutral, freeze-dried overnight, and then dissolved in ethanol to obtain a transparent dispersion of nano-oxide.

[0019] The method described above applies to the synthesis of the following nano-oxides or mixed oxides: titanium oxide, aluminum oxide, manganese oxide, cerium oxide, zirconium oxide, silicon oxide, tungsten oxide, etc.

[0020] 2. Preparation of support oxide 2.1 Hydrothermal method A precursor salt or hydrate corresponding to one or more of the metals (cobalt, nickel, aluminum, copper, ruthenium) that dissociate hydrogen gas is dissolved in a solvent at a certain concentration (0.01 mol / L-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 milliliters of solvent and added to the above suspension to form a stock solution. The autoclave is sealed and hydrothermally treated at a certain temperature (80°C-220°C) for a period of time (1-24 h). The resulting precursor is washed with deionized water multiple times until the pH of the washing solution is neutral, and then freeze-dried overnight to obtain the metal-supported oxide.

[0021] 2.2 Co-precipitation method A precursor salt or hydrate corresponding to one or more of the metals that dissociate hydrogen gas (cobalt, nickel, aluminum, copper, ruthenium) is dissolved in a solvent at a certain concentration (0.01 mol / L to 5 mol / L) and ultrasonically stirred until completely dissolved. An appropriate amount of precipitant solution is dropped into the precursor salt solution while stirring vigorously, and after the dropwise addition is completed, stirring is continued for 4 hours, followed by centrifugal washing three times with absolute ethanol, drying in an oven, polishing, and then calcining in a muffler furnace to obtain a metal-supported oxide.

[0022] 3. Synthesis of Reverse Catalyst 3.1 In situ deposition precipitation of metal precursors in nanoparticle solutions A precursor salt or hydrate corresponding to one or more of the metals (cobalt, nickel, aluminum, copper, ruthenium) that dissociate hydrogen gas is dissolved in a solvent at a certain concentration (0.01 mol / L to 5 mol / L) and ultrasonically stirred until completely dissolved. Then a certain amount of the nano-oxide suspension produced in step 1 is dripped into the above solution at a certain molar ratio. A precipitant solution of a certain concentration is dripped into the suspension under vigorous stirring, and the pH value is controlled to about 9. The obtained precipitate is aged at room temperature for another hour, then filtered and washed with deionized water at room temperature. The obtained material is dried in air overnight and calcined in still air. After the calcination is completed, it is reduced in a hydrogen gas atmosphere, and the nano-oxide obtained by reduction is supported on the metal solid to obtain the reverse catalyst produced.

[0023] 3.2 Excessive immersion The metal support oxide powder produced in step 2 (or the metal support reduced and passivated in step 2) is dispersed in 100 mL of anhydrous ethanol. Then, a certain amount of the nano-oxide suspension produced in step 1 is dropped into the above solution at a certain molar ratio. Then, the mixture is stirred for 0.5 h and then ultrasonicated for 1 h to disperse the slurry well. Then, the slurry is condensed and refluxed at 70 °C for 2 h. Then, the solution is spin-dried, and the resulting precipitate is freeze-dried overnight. After freeze-drying, the precipitate is reduced in a hydrogen gas (residual nitrogen gas) atmosphere, and the nano-oxide obtained by reduction is supported on the metal solid to obtain the catalyst produced.

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

[0025] In the present invention, the metal loading rate is the mass percentage of the amount of the metal substance relative to the total amount of the catalyst substance, and is calculated by the formula: metal loading amount=amount of metal substance / total amount of catalyst substance×100%. In the present invention, the particle size of the solid catalyst carrier is 10-200 mesh (20 mesh, 30 mesh, 60 mesh, 80 mesh, 100 mesh, 150 mesh), and is placed in a gas-solid phase to carry out the carbon dioxide methanation reaction.

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

[0027] In one specific embodiment, the results of the catalyst stability experiment are as follows: after stable operation for 1500 hours, the carbon dioxide conversion rate is maintained at about 90%, the methane selectivity is >99%, the reaction temperature is 200°C, and the pressure is normal pressure.

[0028] Hereinafter, the embodiments of the present invention will be described more specifically with reference to examples and comparative examples.

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

[0030] 0.01 mol Ni(NO 3 )·6H 2 100 mL of ethanol was dissolved in 100 mL of anhydrous ethanol. Then, a certain amount of the nano-zirconium oxide and nano-manganese oxide mixed oxide suspension prepared above was added dropwise to the nickel nitrate solution in a molar ratio of Ni:Mn:Zr=40:3:3. While stirring vigorously (500 r), an appropriate amount of 0.50 molL -1 Na 2 CO 3 The solution (0.5 mol / L, 50 ml) was injected into the precursor salt solution by a syringe pump (1 ml / min), and the pH value of the solution was controlled at about 9. The obtained precipitate was aged at room temperature for another hour, then filtered and washed with deionized water at room temperature. The obtained material was dried in air at 75 °C overnight, and calcined in still air at 400 °C for 3 hours. After the calcination was completed, it was reduced in a hydrogen gas atmosphere at 450 °C for 3 hours. The reduced solid powder was the produced reverse catalyst, ZrMnO 4 It was written as / Ni.

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

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

[0033] 0.01 mol Ni(NO 3 )6H 2 100 mL of ethanol was dissolved in 100 mL of anhydrous ethanol. Then, a certain amount of the nano-zirconium oxide and nano-titanium oxide mixed oxide suspension prepared above was added dropwise to the nickel nitrate solution in a molar ratio of Ni:Ti:Zr=40:3:3. An appropriate amount of 0.50 molL was added while stirring vigorously (500 r). -1 Na 2 CO 3The solution (0.5 mol / L 50 ml) was injected into the precursor salt solution by a syringe pump (1 ml / min), and the pH value of the solution was controlled at about 9. The obtained precipitate was aged at room temperature for another hour, then filtered and washed with deionized water at room temperature. The obtained material was dried in air at 75 °C overnight, and calcined in still air at 400 °C for 3 hours. After the calcination was completed, it was reduced in a hydrogen gas atmosphere at 450 °C for 3 h. The reduced solid powder was the produced reverse catalyst, ZrTiO 4 It was written as / 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 methanation reaction. The molar ratio of the carbon dioxide and hydrogen gas flowing in the reaction gas was 1:4, and the space velocity was 21,000 h -1 The reaction pressure was normal pressure and the reaction temperature was 130-320°C.

[0035] [Example 3] Same as Example 2, except the precursor salts were nickel nitrate hexahydrate, titanium tetrachloride and cerium chloride.

[0036] [Example 4] Same as Example 1, except the precursor salts were nickel nitrate hexahydrate, aluminum chloride and zirconium chloride.

[0037] [Example 5] The same as in Example 1, except that the support precursor salts were nickel nitrate hexahydrate and aluminum nitrate nonahydrate, 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] Same as Example 1, except the support precursor salt was cobalt nitrate hexahydrate.

[0039] [Example 7] 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 50mL of water at a concentration of 0.075mol / L and stirred until completely dissolved. Then, the zirconium chloride and manganese chloride solution was added to 50mL of 2.5% aqueous ammonia solution and stirred for 2h to obtain zirconium hydroxide and manganese hydroxide sol. Finally, it was added to 20mL of absolute ethanol to obtain zirconium ethoxide and manganese ethoxide sol. 5g of zirconium ethoxide and manganese ethoxide sol was added to a mixture of oleic acid:oleylamine:ethanol (40mL:5mL:5mL) and stirred uniformly, then transferred to a 100mL polytetrafluoroethylene-lined autoclave. The autoclave was then sealed and heated at 200℃ for 12h. The resulting precipitate was washed with deionized water several times until the pH of the washing solution was neutral, freeze-dried overnight to obtain nano-zirconium oxide and nano-manganese oxide, and dispersed in ethanol to obtain a transparent dispersion of nano-zirconium oxide and nano-manganese oxide mixed oxide.

[0041] 0.01 mol Ni(NO 3 )·6H 2 A certain amount of the nano-zirconium oxide and nano-manganese oxide mixed oxide suspension prepared above was then dropped into the nickel nitrate solution in a molar ratio of Ni:Mn:Zr=40:3:3. An appropriate amount of 0.50 mol L was added dropwise while stirring vigorously (500 r). -1 Na 2 CO 3 The solution (0.5 mol / L 50 ml) was injected into the precursor salt solution by a syringe pump (1 ml / min) and the pH value of the solution was controlled at about 9. The obtained precipitate was aged at room temperature for another hour, then filtered and washed with deionized water at room temperature. The obtained 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 with vigorous stirring. The suspension was then evaporated to dryness in a water bath at 60°C and dried at 110°C. The resulting solid was ZrMnO x The catalyst was expressed as ZrMnO / Ni-Ru and calcined in air at 400 °C for 3 h. After calcination, it was reduced in a hydrogen gas atmosphere at 450 °C for 3 h. The solid powder obtained by reduction was the reverse catalyst produced, ZrMnO 4 Written as / Ni-Ru.

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

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

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

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

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

[0048] Sheet-shaped nickel foam (0.47 g) with a length of 3 cm, width of 2 cm, and thickness of 2 mm was ultrasonically treated with dilute hydrochloric acid (2 mol / L), ethanol, and deionized water for 30 min, respectively. After the treatment, the nickel foam was immersed in the above 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 h, the resulting nickel foam was washed multiple times with deionized water, the resulting material was dried in air at 75 °C overnight, and calcined in still air at 400 °C for 3 h. After the calcination, it was reduced in a hydrogen gas atmosphere at 450 °C for 3 h. The sheet-shaped material obtained by the reduction is the reverse catalyst to be produced, ZrMnO 4 It is marked / NF.

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

[0050] [Comparative Example 1] Same as Example 1, except that the molar ratio of Ni / Zr / Mn was 40 / 1 / 9.

[0051] [Comparative Example 2] Same as Example 1, except that the molar ratio of Ni / Zr / Mn was 40 / 9 / 1.

[0052] [Comparative Example 3] Same as Example 1, except that the molar ratio of Ni / Zr / Mn was 6 / 20 / 20.

[0053] [Comparative Example 4] Same as Example 1, except that the Ni / Mn molar ratio was 6 / 40.

[0054] [Comparative Example 5] Same as Example 1, except that the Ni / Zr molar ratio was 6 / 40.

[0055] [Comparative Example 6] Same as Example 1, except the precipitant was ammonium carbonate.

[0056] [Comparative Example 7] Same as Example 1 except the precipitant was ammonium valerate.

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

[0058] [Comparative Example 9] Same as Example 1, except the precipitant was sodium hydroxide.

[0059] [Comparative Example 10] Zirconium chloride and manganese chloride were dissolved in 50mL of water at a concentration of 0.075mol / L and stirred until completely dissolved. Then, the zirconium chloride-manganese chloride solution was added to 50mL of 2.5% aqueous ammonia solution and stirred for 2h to obtain zirconium hydroxide-manganese hydroxide sol, and finally, it was added to 20mL of absolute ethanol to obtain zirconium ethoxide-manganese ethoxide sol. 5g of zirconium ethoxide-manganese ethoxide sol was added to a 40mL:5mL:5mL mixture of oleic acid:oleylamine:ethanol and stirred uniformly, and then transferred to a 100mL polytetrafluoroethylene-lined autoclave. The autoclave was then sealed and heated at 200℃ for 12h. The resulting precipitate was washed multiple times with deionized water until the pH of the washing solution was neutral, and freeze-dried overnight to obtain nano-zirconium oxide-nano-manganese oxide mixed oxide, which was then dispersed in ethanol to obtain a transparent dispersion of nano-zirconium oxide-nano-manganese oxide mixed 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 above suspension to form a stock solution. The autoclave was then sealed and heated at 140 °C for 12 h, and the precipitate was collected by centrifugation, washed with deionized water and ethanol, and freeze-dried overnight. The resulting solid was heated in a tube furnace at 400 °C for 3 h 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. Then, a certain amount of the nano-zirconium oxide-nano-manganese oxide mixed oxide suspension prepared above was dropped into the round-bottom flask with a molar ratio of Ni:Mn:Zr=40:3:3. Then, the slurry was stirred for 0.5 h and ultrasonicated for 1 h to ensure good dispersion. Then, the slurry was condensed and refluxed at 70 °C for 2 h. The flask was transferred to a rotary evaporator, heated to 60 °C, and the rotation speed was controlled at 200 r / min. The solution was rotary dried, and the resulting precipitate was freeze-dried overnight.

[0062] After freeze-drying, the mixture was reduced in a hydrogen gas atmosphere at 400 °C for 2 h. The reduced solid powder (ZrMnO 4 The solid catalyst had a particle size of 60-80 mesh and was placed in the gas-solid phase to carry out the carbon dioxide methanation reaction. The molar ratio of the carbon dioxide and hydrogen gas flowing in the reaction gas was 1:4, and the space velocity was 21,000 h -1 The reaction pressure was normal pressure and the reaction temperature was 150-300°C.

[0063] [Comparative Example 11] It was the same as Comparative Example 10, except that the support precursor salt was nickel nitrate hexahydrate, the supported metal oxide precursor salt was manganese chloride, and the molar ratio of Ni / Mn was 40 / 6.

[0064] [Comparative Example 12] It was the same as Comparative Example 10, except that the support precursor salt was nickel nitrate hexahydrate, the supported metal oxide precursor salt was zirconium chloride, and the molar ratio of Ni / Zr was 40 / 6.

[0065] [Comparative Example 13] Same as 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] Same as Example 2, except that the support precursor salt was nickel nitrate hexahydrate, the supported metal oxide precursor salt was tetrabutyl titanate, and the molar ratio of Ni / Ti was 6 / 40.

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

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

[0069] [Comparative Example 17] Glucose (0.01 mol) and acrylamide (0.015 mol) were dissolved in deionized water (80 mL) after stirring, and then 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 value to about 10. After stirring for 5 h, the mixture was transferred to a 100 mL polytetrafluoroethylene-lined autoclave. The autoclave was hydrothermally treated at 180 °C for 72 h and cooled to room temperature. After that, the solid precipitate was collected by filtration and washed with deionized water and absolute ethanol several times. It was dried at 100 °C for 10 h and then heated at 600 °C with a heating rate of 5 °C min -1 2 hours, and La-CeO 2 The value was set at -600.

[0070] Nickel nitrate hexahydrate (0.165 g) was dissolved in a certain amount of ethylene glycol (0.2 mL), and the solution was added dropwise to the prepared carrier (0.3 g), sealed at 40° C. for 24 h, dried at 100° C. for 12 h, and then incubated in air for 5 min. -1 After the firing, the mixture was reduced in a hydrogen gas atmosphere at 400°C for 2 hours. 2 is the catalyst produced [1] It was.

[0071] [Comparative Example 18] A certain amount of nickel nitrate hexahydrate and ruthenium(III) nitrosylnitrate solution were mixed in 40 mL of deionized water, and a certain amount of Ce 0.5 Zr 0.5 O 2 (commercial) and the suspension was evaporated to dryness in a water bath at 50° C. and dried at 110° C. The resulting solid was Ni-Ru / CeZrO xThe Ni-Ru / Ce alloy was calcined in air at 400°C for 3 hours, and then reduced in a hydrogen gas atmosphere at 400°C for 2 hours. 0.5 Zr 0.5 O 2 is the catalyst produced [2] It was.

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

[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 TiO was added to the mixture while stirring at room temperature. 2 (about 2 g) was slowly added to the aqueous solution. The suspension was left for 3 hours and then heated to 80° C. to remove the remaining H 2 Finally, the solid obtained was dried overnight at 110 °C in a static air oven to obtain Ni-Mn / TiO 2 is the catalyst produced [3] It was.

[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 hydrothermally reacted at 120 °C for 12 h. 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 h. The Ni 0.73 Zr 0.03 Al 0.24 The resulting Ni 0.73 Zr 0.03 Al 0.24 -LDH was heated at 600 °C for 12 h. 2 The mixture was reduced in gas for 2 h (heating rate 5°C / min -1 , H 2 Flow rate 50mLmin -1 ) After that, the catalyst produced [4] obtained.

[0075] [Comparative Example 22] The treated cylindrical nickel foam, 5 cm long and 2 cm in diameter, 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) and stirred for 30 min, then transferred to a 100 mL polytetrafluoro-lined autoclave. The autoclave was then sealed and heated at 110 °C for 8 h, and the resulting precursor was washed multiple times with deionized water and dried at 65 °C in air for 12 h. Finally, the precursor was heated in a tubular furnace at 500 °C with a heating rate of 2 °C / min under flowing H 2 / N 2 The Ni-Fe-Al / NF obtained by in-situ reduction in a 1 / 10 atmosphere (V / V) was [5] It was.

[0076] [Comparative Example 23] Cerium nitrate hexahydrate and chromium nitrate nonahydrate were dissolved in 30 mL of deionized water with a Cr / Ce molar ratio of 1:9. Aqueous ammonia was added dropwise to the precursor salt solution with continuous stirring until complete precipitation at pH = 10. The mixture was filtered to collect the precipitate and washed repeatedly with deionized water. The solid was dried at 110 °C overnight and calcined at 500 °C for 4 h to obtain Cr-CeO 2 A carrier was obtained.

[0077] Cr-CeO 2 RuCl 3 3H 2 The mixture was evaporated in a 70 °C water bath with vigorous stirring for 4 h and then further dried at 110 °C overnight. The resulting solid was 2 / Cr-CeO 2 The resulting Ru / Cr-CeO was calcined in air at 500°C for 4 h, and then reduced in a hydrogen gas atmosphere at 400°C for 2 h. 2 is the catalyst produced [6] It was.

[0078] [Comparative Example 24] Ru-TiO 2 0.6 g of ruthenium(III) chloride hydrate was diluted to 50 mL with deionized water and 2.0 g of anatase titanium dioxide was added with vigorous stirring. The suspension was then evaporated to dryness in a water bath at 50 °C and dried at 110 °C. The resulting solid was Ru / TiO 2 The Ru / TiO 2 was the catalyst prepared. Ru / TiO 2 The Ru loading in the catalyst was 10 wt %.

[0079] [Comparative Example 25] Commercial Ru / Al 2 O 3 Ru-TiO 2 and commercial Ru-Al 2 O3 The same as in Example 1, except that the reduction temperature was 200°C.

[0080] Table 1 shows the results of each catalyst. 2 CO when used in methanation reactions 2 The conversion was shown.

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

[0082] Compared to the Comparative Example, Examples 1 to 13 in Table 1 show that CO 2 The methanation activity of the reverse oxide / metal catalyst compared to that of the conventional forward metal / oxide catalyst at low temperatures. 2 It exhibits excellent performance in catalysis of methanation reactions.

[0083] Figure 1 shows the CO 2 Thermodynamic diagrams of the change with temperature of the methanation reaction and the by-reaction, the reverse water gas shift reaction, are shown. The methanation reaction is highly exothermic and low temperatures favor the reaction, while the reverse water gas shift reaction is endothermic and high temperatures favor the production of CO.

[0084] FIG. 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 showed excellent performance at 170-180℃ and was stable for 21,000h. -1 CO near equilibrium conversion at space velocity 2 The conversion performance was achieved, and the selectivity for the target product methane was >99.9%, which was comparable to that of the commercial Ru / Al catalyst. 2 O 3 Catalyst and Ru / TiO 2 The performance of the catalyst is much higher than that of the conventional catalyst. x The forward catalyst supported on oxide solid solution is a catalyst with more than 50% CO2 To achieve conversion, temperatures above 260°C are required.

[0085] FIG. 3 shows the results of Example 1 at 190° C. for 21,000-127,000 h. -1 As can be seen, even at high space velocities, the methanation activity of the reverse ZrMnO x / Ni catalyst still has high CO 2 Conversion and methane selectivity close to 100% were maintained.

[0086] FIG. 4 shows the stability test results of Example 1 at 180° C. for 1500 hours, and the catalytic activity did not change significantly after 1500 hours of operation.

[0087] Figure 5 shows the reaction results of Example 1 and Comparative Examples 6, 7, 8, and 9. Different precipitants, sodium carbonate, ammonia water, ammonium carbonate, ammonium butylate, and sodium hydroxide, were used to produce high-performance reverse methanation catalysts at low temperatures. The effect was the highest when sodium carbonate was used as the precipitant.

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

[0089] Table 1 shows the comparison results between Examples 1, 9, 10, and 13 and Comparative Examples 10, 11, and 12. The excess immersion method, the sedimentation precipitation method, and the preparation method of immersing oxide nanoparticle precursor salt in a porous monolith catalyst can all synthesize reverse methanation catalysts with excellent performance.

[0090] FIG. 7 shows the reaction results of Examples 9-10 and Comparative Examples 4-5. As can be seen from the results, the two-way reverse catalyst also has better reaction performance than the conventional forward catalyst, which is consistent with the tendency of the three-way reverse catalyst.

[0091] FIG. 8 is a HAADF-STEM photograph of the catalyst produced in Example 1. It was found that the particle size of the catalyst metal support produced in the present invention was about 10 nm, and the oxide was uniformly dispersed in the metal support.

[0092] The above are only preferred embodiments of the present application, and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

[0093] References [1] Zhang T, Wang W, Gu F, et al. Enhancing the low-temperature CO 2 Methane ionization over Ni / La-CeO 2 catalyst: The effects of surface oxygen vacancy and basic site on the catalytic performance[J]. Applied Catalysis B: Environmental, 2022, 312: 121385. [2] Merkouri LP, Le Sache E, Pastor-Perez L, et al. Versatile Ni-Ru catalysts for gas phase CO 2 conversion: Bringing closer dry reforming, reverse water gas shift and methanation to enable end-products flexibility[J]. Fuel, 2022, 315: 123097. [3] Vrijburg WL, Moioli E, Chen W, et al. Efficient base-metal NiMn / TiO 2 catalyst for CO 2Methanation[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 CO 2 methanation[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 CO 2 Methanation[J]. Chemical Engineering Journal, 2021, 420: 127693. [6] Xu X, Liu L, Tong Y, et al. Facile Cr 3+ -doping strategy dramatically promoting Ru / CeO 2 for low-temperature CO 2 Methanation: Unraveling the roles of surface oxygen vacancies and hydroxyl groups[J]. ACS Catalysis, 2021, 11(9): 5762-5775.

[0094] (Additional Note) (Appendix 1) A solid reverse catalyst, comprising a metal that dissociates hydrogen gas as a carrier, a nano-oxide that generates oxygen vacancies and adsorbs activated carbon dioxide as a carrier phase, the nano-oxide being uniformly dispersed on the surface of the metal carrier, and having a nano-oxide / metal reverse interface structure; The support metal is one or more selected from cobalt, nickel, aluminum, copper, and ruthenium; The support phase nano-oxide 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 molar fraction of the supported phase metal is 0.01 to 30% based on the total molar amount of the metal in the support and the supported phase.

[0095] (Appendix 2) A method for producing the solid reverse catalyst according to claim 1, comprising the steps of: The manufacturing method includes: preparing a carrier precursor under conditions of a precipitant and a solvent by a hydrothermal method or a co-precipitation method; Producing a nano-oxide dispersion liquid by a sol method under conditions of a precipitant, a solvent and a protective agent; A method for preparing a solid reverse catalyst, comprising the steps of depositing or immersing nano-oxides in a carrier precursor by in-situ precipitation or over-immersion, calcining and reducing the obtained powdery solid, and then dispersing the nano-oxides uniformly on the surface of the metal carrier to obtain a solid reverse catalyst.

[0096] (Appendix 3) The method includes the following steps (1) and (2), (1) In the synthesis of nano-oxides, The precursor salt of the support phase is dissolved in a solvent, the resulting solution is put into a precipitant solution to obtain a hydroxide sol, the resulting hydroxide sol is put into ethanol to obtain a hydroxide-ethanol sol, and the hydroxide-ethanol sol is dispersed in a mixed solution of oleic acid / oleylamine / ethanol, stirred uniformly, transferred to an autoclave, sealed, and solvent heat-treated at 80-220°C for 1-24h, after which the solid product is collected, washed with deionized water until the pH of the washing solution becomes neutral, freeze-dried, and obtained nano-oxide, which is dispersed in ethanol to obtain a nano-oxide dispersion; the precursor salt of the support phase is one or more selected from titanium tetrachloride, tetrabutyl titanate, aluminium nitrate, aluminium nitrate hydrate, aluminium 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, tungsten chloride; (2) In the synthesis of a solid reverse catalyst, Dissolve the precursor salt of the carrier in a solvent, add the nano-oxide dispersion prepared in step (1) dropwise to the resulting solution, and then add the precipitant solution dropwise under stirring, control the pH to 9, and then age at room temperature, filter, wash, dry, and calcinate in still air. After calcination, reduce in a hydrogen gas atmosphere to prepare a solid reverse catalyst; 3. The method for producing a solid reverse catalyst according to claim 2, wherein the precursor salt of the support is one or more selected from the group consisting of 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] (Appendix 4) The method for producing a solid reverse catalyst according to claim 3, characterized in that in step (1) or step (2), the solvent is one or more selected from the group consisting of water, methanol, ethanol, butanol, tetrahydrofuran, and methyl t-butyl ether.

[0098] (Appendix 5) The method for producing a solid reverse catalyst according to claim 3, wherein in step (1) or step (2), the precipitating agent is one or more selected from the group consisting of ammonium carbonate, aqueous ammonia, urea, sodium hydroxide, sodium bicarbonate, ammonium valerate, and valeric acid.

[0099] (Appendix 6) The method for producing a solid reverse catalyst according to claim 3, wherein in step (2), the calcination temperature is 200 to 600° C. and the calcination time is 1 to 12 hours.

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

[0101] (Appendix 8) Use of the solid reverse catalyst according to claim 1 in a carbon dioxide methanation reaction.

[0102] (Appendix 9) The method of use comprises: The solid reverse flow catalyst is placed in a fixed bed reactor. The molar ratio of the flowing carbon dioxide and hydrogen gas is 1:4. The gas hourly space velocity is 9000-127000 h -1 The use according to claim 8, wherein the reaction pressure ranges from normal pressure to 6 MPa and the reaction temperature ranges from 25 to 450°C.

Claims

1. A solid reverse catalyst, comprising a metal that dissociates hydrogen gas as a support, a nano-oxide that generates oxygen vacancies and adsorbs activated carbon dioxide as a support phase, the nano-oxide being uniformly dispersed on the surface of the metal support, and having a nano-oxide / metal reverse interface structure; the support metal is one or more selected from cobalt, nickel, aluminum, and ruthenium; the support phase nano-oxide is one or more selected from titanium oxide, aluminum oxide, manganese oxide, zirconium oxide, silicon oxide, tungsten oxide; A solid reverse catalyst, characterized in that the molar fraction of the supported phase metal is 0.01 to 30% relative to the total molar amount of the metal in the support and the supported phase.

2. The method includes the following steps (1) and (2): (1) In the synthesis of nano-oxides, The precursor salt of the support phase is dissolved in a solvent, the resulting solution is added to a precipitant solution to obtain a hydroxide sol, the resulting hydroxide sol is added to ethanol to obtain a hydroxide-ethanol sol, and 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 until the pH of the washing solution becomes neutral, freeze-dried to obtain a nano-oxide, and the nano-oxide is dispersed in ethanol to obtain a nano-oxide dispersion; the precursor salt of the support 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, zirconium nitrate, zirconium nitrate hydrate, zirconium chloride, tetraethyl orthosilicate, ammonium metatungstate, sodium tungstate, tungsten chloride; (2) In the synthesis of a solid reverse catalyst, Dissolve the precursor salt of the carrier in a solvent, add the nano-oxide dispersion prepared in step (1) dropwise to the resulting solution, and then add the precipitant solution dropwise while stirring, adjust the pH to 9, and then age at room temperature, filter, wash, dry, and calcinate in static air. After calcination, reduce in a hydrogen gas atmosphere. After the reduction, the nano-oxide is uniformly dispersed on the surface of the metal carrier to prepare a solid reverse catalyst; 2. The method for preparing a solid backward catalyst according to claim 1, wherein the precursor salt of the support is one or more selected from the group consisting of cobalt nitrate, cobalt nitrate hydrate, cobalt chloride, nickel nitrate, nickel nitrate hydrate, nickel chloride, and ruthenium chloride.

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

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

5. 3. The method for preparing a solid backward catalyst according to claim 2, wherein in step (2), the calcination temperature is 200-600°C and the calcination time is 1-12 hours.

6. 3. The method for preparing a solid reverse catalyst according to claim 2, wherein in step (2), the reduction temperature is 200-700°C, the reduction time is 1-6h, the hydrogen gas concentration in the reduction atmosphere is 5-100%, and the total flow rate is 5-100ml / min.

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

8. The method of use comprises: The solid reverse flow catalyst is placed in a fixed bed reactor, and the molar ratio of the flowing carbon dioxide and hydrogen gas is 1:

4. The gas hourly space velocity is 9,000-127,000 h －１ The use according to claim 7, characterized in that the reaction pressure ranges from atmospheric pressure to 6 MPa, and the reaction temperature ranges from 25 to 450°C.

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