A cerium oxide supported ruthenium-cobalt bimetallic catalyst for ammonia decomposition and a method for preparing the same

Abstract

This invention discloses a cerium oxide-supported ruthenium-cobalt bimetallic catalyst for ammonia decomposition and its preparation method. The cerium oxide-supported ruthenium-cobalt bimetallic catalyst of this invention has an active metal ruthenium mass percentage of 0.5-3.0 wt% and an active metal cobalt mass percentage of 0.5-1.5 wt%. In the catalyst preparation process, concentrated nitric acid and deionized water are first mixed, and cerium salt precursor and cobalt precursor are added to obtain an acid-water mixed solution of cerium and cobalt. Then, an alcohol solution containing P123 is added, and the mixture is stirred, aged, washed, centrifuged, and dried to obtain a powder sample. Subsequently, the sample is calcined in an oxygen-containing gas, cooled, and impregnated with a ruthenium precursor alcohol solution to introduce the ruthenium active component. Finally, the sample is carbonized and reduced in a carbon-containing gas to obtain the cerium oxide-supported ruthenium-cobalt bimetallic catalyst. The catalyst of this invention exhibits excellent ammonia decomposition performance and has good application prospects.

Description

Technical Field

[0001] This invention belongs to the field of ammonia decomposition catalyst technology, specifically a cerium oxide-supported ruthenium-cobalt catalyst for ammonia decomposition and its preparation method. Background Technology

[0002] Hydrogen possesses advantages such as high heat of combustion and zero emissions during combustion, making it a clean, efficient, and pollution-free green energy source and a crucial component of future national low-carbon energy systems. However, hydrogen's low density and wide explosion limits (4%–75%) lead to safety issues during storage and transportation, hindering the development of hydrogen energy. Therefore, there is an urgent need to develop safe and efficient hydrogen storage materials and hydrogen production technologies. Ammonia molecules contain up to 17.6% hydrogen by mass. Furthermore, ammonia is a major chemical in modern agriculture and industry, with high yields and mature transportation technologies, making it an ideal hydrogen energy carrier. Efficient ammonia decomposition technology is a prerequisite for ammonia as a hydrogen energy carrier, and the key lies in the development of highly efficient ammonia decomposition catalysts.

[0003] Each mole of ammonia decomposes to produce 0.5 moles of nitrogen and 1.5 moles of hydrogen. The ammonia decomposition reaction is thermodynamically endothermic, typically requiring high reaction temperatures to ensure complete ammonia decomposition. For example, the ammonia decomposition temperature of widely used commercial cobalt-based catalysts is usually above 800°C. Furthermore, Chinese patent document CN115318317A discloses a low-cost Fe / SiC ammonia decomposition catalyst; however, Fe readily undergoes nitridation at low temperatures, forming nitrides, and Fe metal particles tend to agglomerate into large particles, significantly reducing ammonia decomposition activity and hindering industrial application. In addition, ruthenium-based ammonia decomposition catalysts, with ruthenium as the active component, exhibit high ammonia decomposition performance at low temperatures, but their high cost prevents large-scale industrial application. Various methods have been employed to improve the performance of ruthenium-based ammonia decomposition catalysts. These include introducing alkaline oxides such as MgO and La₂O₃ to adjust the properties of the support and optimize the state of the active metal, or utilizing the strong interactions between composite oxide supports like CeO₂-La₂O₃ and MgO-Al₂O₃ and the metal to enhance the ammonia decomposition performance of ruthenium catalysts. However, the high cost of ruthenium catalysts and their low ammonia decomposition activity under low-temperature reaction conditions severely hinder the development of ammonia decomposition technology and hydrogen energy technologies using ammonia as a hydrogen storage material. Summary of the Invention

[0004] To address the shortcomings of the existing technology, and considering that the ammonia decomposition process consists of different reactions including ammonia adsorption, decomposition, and desorption of the products nitrogen and hydrogen, and that the active sites required for different reaction steps have different properties, this invention proposes an ammonia decomposition catalyst with cerium oxide as a support and containing two active components, cobalt and ruthenium. Through the synergistic effect of the two different active sites, ruthenium and cobalt, in the catalyst, excellent ammonia decomposition activity is achieved.

[0005] To achieve the above objectives, the present invention adopts the following technical solution.

[0006] A cerium oxide-supported ruthenium-cobalt bimetallic catalyst for ammonia decomposition, the catalyst comprising a cerium oxide support and two active components, ruthenium and cobalt, wherein the mass percentage of active metal ruthenium is 0.5-3.0 wt% and the mass percentage of active metal cobalt is 0.2-1.5 wt%.

[0007] The preparation method of the above-mentioned cerium oxide-supported ruthenium-cobalt bimetallic catalyst includes the following steps: 1) Mix concentrated nitric acid and deionized water to obtain an acid-water mixture; 2) Add the cerium salt precursor and cobalt precursor to the acidic aqueous mixture and stir until completely dissolved to obtain an acidic aqueous mixture containing cerium and cobalt; 3) Add nonionic surfactant P123 to alcohol solvent and stir to obtain an alcohol solution containing P123; 4) The acidic aqueous solution containing cerium and cobalt obtained in step 2) is added dropwise to the alcoholic solution containing P123 obtained in step 3), and the mixture is stirred, aged, washed, centrifuged and dried to obtain a powder sample; 5) Calcine the powder sample obtained in step 4) in an oxygen-containing gas; 6) The sample obtained in step 5) is immersed in a ruthenium precursor alcohol solution to introduce the ruthenium active component; 7) The sample obtained in step 6) is carbonized and reduced in a carbon-containing gas to obtain a cerium oxide-supported ruthenium-cobalt bimetallic catalyst.

[0008] This invention involves adding P123 (EO) to a cerium- and cobalt-containing acidic aqueous solution. 20 PO 70 EO 20 A cobalt-containing cerium oxide sample was prepared by impregnating a ruthenium precursor alcohol solution with a carbonization treatment and reduction steps in a carbon-containing gas.

[0009] Further, in step 1), the volume ratio of concentrated nitric acid to deionized water is 0.8-2:1.

[0010] Further, in step 2), the cerium salt precursor is one of cerium nitrate, cerium acetate, and cerium chloride, and the cobalt precursor is one of cobalt nitrate, cobalt chloride, cobalt acetate, and cobalt oxalate.

[0011] Further, in step 3), the alcohol solvent is one of ethanol, n-butanol, isopropanol, and n-propanol.

[0012] Further, in step 3), the concentration of P123 in the alcohol solution containing P123 is 15-60 mg / mL.

[0013] Further, in step 4), the aging process involves standing at 35-120°C for 3-24 hours; the washing solution used is methanol or ethanol.

[0014] Furthermore, in step 5), the oxygen volume content in the oxygen-containing gas is 20-100%; the calcination temperature is 500-1000℃; and the treatment time is 2-48 hours.

[0015] Further, in step 6), the ruthenium precursor is one of ruthenium nitrite, ruthenium acetylacetonate, or ruthenium acetate; the ruthenium precursor is dried at 60-110°C for 0.2-5 hours before the preparation of the ruthenium precursor alcohol solution; the solvent in the alcohol solution is methanol or ethanol.

[0016] Further, in step 7), the carbon-containing gas is a mixture of CO, CH4, C2H6 and nitrogen or an inert gas, wherein the volume content of the carbon-containing gas is 20-100%; the carbonization temperature is 400-700℃, and the treatment time is 1-20 hours; the reduction is performed in a hydrogen-containing gas at 200-600℃ for 0.5-24 hours, wherein the volume ratio of hydrogen in the hydrogen-containing gas is 5%-100%.

[0017] The beneficial effects of this invention are as follows: Compared to cerium oxide-supported ruthenium catalysts without cobalt and cerium oxide-supported ruthenium-cobalt bimetallic catalysts prepared by conventional methods, the ruthenium electronic properties in the catalyst of this invention change, leading to a redshift in the infrared spectral signal of CO species linearly adsorbed on metal Ru particles. This change in ruthenium electronic properties enhances the ammonia decomposition capacity of the sample. Simultaneously, thanks to the optimization of catalyst properties such as the metal-support interaction, the diffusion and adsorption capacity of hydrogen atoms on the surface of the cerium oxide-supported ruthenium-cobalt bimetallic catalyst of this invention is significantly improved. Timely removal of hydrogen during the ammonia decomposition reaction effectively prevents the accumulation of large amounts of hydrogen on the catalyst surface, improving the utilization efficiency of active sites and effectively promoting the continuous ammonia decomposition reaction. This results in a catalyst exhibiting superior ammonia decomposition activity and promising application prospects. Attached Figure Description

[0018] The present invention will now be further described with reference to the accompanying drawings.

[0019] Figure 1 The following are the DRIFTS spectra of CO adsorption at 50°C for three catalysts: Comparative Example 1, Comparative Example 4, and Example 1. Figure 2Comparison chart showing the color changes of the catalyst and WO3 mixture prepared in Comparative Example 1 and Example 1 when hydrogen-treated at 80°C for different times. Detailed Implementation

[0020] To make the content of this invention easier to understand, the technical solution of this invention will be further described below with reference to specific embodiments, but this invention is not limited thereto.

[0021] Example 1: 5 mL of concentrated nitric acid was added to 5 mL of deionized water to obtain an acid-water mixture. Cerium nitrate and cobalt nitrate were then added to the acid-water mixture and stirred to dissolve, resulting in an acid-water mixture containing cerium and cobalt. 2 g of P123 was added to 100 mL of n-butanol and stirred to obtain an alcoholic solution containing P123. Subsequently, the acid-water mixture containing cerium and cobalt was added dropwise to the alcoholic solution containing P123. The mixture was stirred at room temperature for 30 minutes, allowed to stand at 100°C for 12 hours, washed 5 times with ethanol, centrifuged, and dried at 120°C overnight. The powder sample was then calcined in air (oxygen content 21%) at 600°C for 12 hours to obtain a cerium oxide sample containing cobalt. Ruthenium nitrosonitrate was dried at 80°C for 1 hour, then dissolved in ethanol to obtain a ruthenium nitrosonitrate ethanol solution. This solution was then impregnated into the cobalt-containing cerium oxide sample and carbonized at 500°C for 6 hours in pure CO gas. Finally, it was reduced in pure hydrogen at 450°C for 6 hours to obtain the cerium oxide-supported ruthenium-cobalt bimetallic catalyst. The catalyst contained 2.5 wt% ruthenium and 1.0 wt% cobalt.

[0022] Example 2: 8 mL of concentrated nitric acid was added to 3 mL of deionized water to obtain an acid-water mixture. Cerium chloride and cobalt chloride were then added to the acid-water mixture and stirred to dissolve, resulting in an acid-water mixture containing cerium and cobalt. 2 g of P123 was added to 75 mL of ethanol and stirred to obtain an alcohol solution containing P123. Subsequently, the acid-water mixture containing cerium and cobalt was added dropwise to the alcohol solution containing P123. The mixture was stirred at room temperature for 30 minutes, allowed to stand at 80 °C for 20 hours, washed 5 times with methanol, centrifuged, and dried overnight at 60 °C. The powder sample was then calcined in pure oxygen (100% oxygen content) at 900 °C for 1 hour to obtain a cerium oxide sample containing cobalt. Ruthenium acetylacetonate was dried at 60°C for 6 hours and then dissolved in methanol to obtain a ruthenium acetylacetonate methanol solution. This solution was then impregnated into the cobalt-containing cerium oxide sample and carbonized at 650°C for 18 hours in pure CH4 gas. Finally, it was reduced at 300°C for 12 hours in a hydrogen-argon mixture with a hydrogen integral of 90% to obtain the cerium oxide-supported cobalt-ruthenium bimetallic catalyst. The catalyst contained 2.2 wt% ruthenium and 1.2 wt% cobalt.

[0023] Example 3: 9 mL of concentrated nitric acid was added to 5 mL of deionized water to obtain an acid-water mixture. Cerium acetate and cobalt acetate were then added to the acid-water mixture and stirred to dissolve, resulting in an acid-water mixture containing cerium and cobalt. 2 g of P123 was added to 80 mL of isopropanol and stirred to obtain an alcoholic solution containing P123. Subsequently, the acid-water mixture containing cerium and cobalt was added dropwise to the alcoholic solution containing P123. The mixture was stirred at room temperature for 60 minutes, allowed to stand at 110 °C for 6 hours, washed 5 times with ethanol, centrifuged, and dried overnight at 100 °C. The powder sample was then calcined at 900 °C for 2 hours in a mixture of oxygen and nitrogen (oxygen content 60%) to obtain a cerium oxide sample containing cobalt. Ruthenium nitrosonitrate was dried at 70°C for 4.5 hours and then dissolved in ethanol to obtain a ruthenium nitrosonitrate ethanol solution. This solution was then impregnated into the cobalt-containing cerium oxide sample and carbonized at 600°C for 3 hours in pure C2H6 gas. Finally, it was reduced at 350°C for 18 hours in a nitrogen-hydrogen mixture with a hydrogen volume ratio of 30% to obtain the cerium oxide-supported cobalt-ruthenium bimetallic catalyst. The catalyst contained 1.0 wt% ruthenium and 1.2 wt% cobalt.

[0024] Example 4: 4 mL of concentrated nitric acid was added to 5 mL of deionized water to obtain an acid-water mixture. Cerium nitrate and cobalt oxalate were then added to the acid-water mixture and stirred to dissolve, resulting in an acid-water mixture containing cerium and cobalt. 2 g of P123 was added to 90 mL of n-propanol and stirred to obtain an alcoholic solution containing P123. Subsequently, the acid-water mixture containing cerium and cobalt was added dropwise to the alcoholic solution containing P123. The mixture was stirred at room temperature for 30 minutes, allowed to stand at 50 °C for 24 hours, washed five times with methanol, centrifuged, and dried overnight at 90 °C. The powder sample was then calcined at 700 °C for 10 hours in a mixture of oxygen and helium (90% oxygen content) to obtain a cerium oxide sample containing cobalt. Ruthenium acetylacetonate was dried at 105°C for 4 hours, then dissolved in ethanol to obtain a ruthenium acetylacetonate ethanol solution. This solution was then impregnated into the cobalt-containing cerium oxide sample and carbonized at 350°C for 12 hours in a mixture of carbon monoxide and argon with a CO volume content of 60%. Finally, it was reduced at 400°C for 20 hours in a hydrogen-argon mixture with a hydrogen volume ratio of 30% to obtain the cerium oxide-supported cobalt-ruthenium bimetallic catalyst. The catalyst contained 1.3 wt% ruthenium and 0.5 wt% cobalt.

[0025] Example 5: 6 mL of concentrated nitric acid was added to 5 mL of deionized water to obtain an acid-water mixture. Cerium nitrate and cobalt nitrate were then added to the acid-water mixture and stirred to dissolve, resulting in an acid-water mixture containing cerium and cobalt. 2 g of P123 was added to 110 mL of n-butanol and stirred to obtain an alcoholic solution containing P123. Subsequently, the acid-water mixture containing cerium and cobalt was added dropwise to the alcoholic solution containing P123. The mixture was stirred at room temperature for 30 minutes, allowed to stand at 90°C for 5 hours, washed 5 times with methanol, centrifuged, and dried overnight at 110°C. The powder sample was then calcined in air (oxygen content 21%) at 550°C for 7 hours to obtain a cerium oxide sample containing cobalt. Ruthenium nitrosonitrate was dried at 70°C for 1.5 hours and then dissolved in ethanol to obtain a ruthenium nitrosonitrate ethanol solution. This solution was then impregnated into the cobalt-containing cerium oxide sample and carbonized at 550°C for 3 hours in pure CO gas. Finally, it was reduced at 550°C for 4 hours in pure hydrogen to obtain the cerium oxide-supported cobalt-ruthenium bimetallic catalyst. The catalyst contained 2.2 wt% ruthenium and 1.3 wt% cobalt.

[0026] Comparative Example 1: 5 mL of concentrated nitric acid was added to 5 mL of deionized water to obtain an acid-water mixture. Cerium nitrate and cobalt nitrate were then added to the acid-water mixture and stirred to dissolve, resulting in an acid-water mixture containing cerium and cobalt. 2 g of P123 was added to 100 mL of n-butanol and stirred to obtain an alcoholic solution containing P123. Subsequently, the acid-water mixture containing cerium and cobalt was added dropwise to the alcoholic solution containing P123. The mixture was stirred at room temperature for 30 minutes, allowed to stand at 100°C for 12 hours, washed 5 times with ethanol, centrifuged, and dried at 120°C overnight. The powder sample was then calcined in air (oxygen content 21%) at 600°C for 12 hours to obtain a cerium oxide sample containing cobalt. Subsequently, the ruthenium nitrosonitrate aqueous solution was impregnated into the cobalt-containing cerium oxide sample, and carbonized in pure CO gas at 500°C for 6 hours. Then, it was reduced in pure hydrogen at 450°C for 6 hours to obtain a cerium oxide-supported cobalt-ruthenium bimetallic catalyst with a ruthenium mass percentage of 2.5 wt% and a cobalt mass percentage of 1.0 wt%.

[0027] Comparative Example 2: 5 mL of concentrated nitric acid was added to 5 mL of deionized water to obtain an acid-water mixture. Cerium nitrate and cobalt nitrate were then added to this acid-water mixture and stirred until dissolved, yielding an acid-water solution containing cerium and cobalt. 2 g of P123 was added to 100 mL of n-butanol and stirred to obtain an alcoholic solution containing P123. The acid-water solution containing cerium and cobalt was then added dropwise to the alcoholic solution containing P123. The mixture was stirred at room temperature for 30 minutes, allowed to stand at 100°C for 12 hours, washed five times with ethanol, centrifuged, and dried overnight at 120°C. The powder sample was then calcined in air (oxygen content 21%) at 600°C for 12 hours to obtain a cobalt-containing cerium oxide sample. Subsequently, an aqueous solution of nitrosorium nitrate was impregnated into the cobalt-containing cerium oxide sample, and then reduced in pure hydrogen at 450°C for 6 hours to obtain a cerium oxide-supported cobalt-ruthenium bimetallic catalyst. The catalyst contained 2.5 wt% ruthenium and 1.0 wt% cobalt.

[0028] Comparative Example 3: 5 mL of concentrated nitric acid was added to 5 mL of deionized water to obtain an acid-water mixture. Cerium nitrate and cobalt nitrate were then added to this acid-water mixture and stirred until dissolved, yielding an acid-water solution containing cerium and cobalt. 10 g of P123 was added to 100 mL of n-butanol and stirred to obtain an alcoholic solution containing P123. The acid-water solution containing cerium and cobalt was then added dropwise to the alcoholic solution containing P123. The mixture was stirred at room temperature for 30 minutes, allowed to stand at 100°C for 12 hours, washed five times with ethanol, centrifuged, and dried overnight at 150°C to obtain a cobalt-containing cerium oxide sample. Subsequently, an aqueous solution of nitrosorium nitrate was impregnated into the cobalt-containing cerium oxide sample, and then reduced in pure hydrogen at 450°C for 6 hours to obtain a cerium oxide-supported cobalt-ruthenium bimetallic catalyst. The catalyst contained 2.5 wt% ruthenium and 1.0 wt% cobalt.

[0029] Comparative Example 4: 5 mL of concentrated nitric acid was added to 5 mL of deionized water to obtain an acid-water mixture. Cerium nitrate was then added to this acid-water mixture and stirred until dissolved, yielding a cerium-containing acid-water solution. 2 g of P123 was added to 100 mL of n-butanol and stirred to obtain a P123-containing alcohol solution. The cerium-containing acid-water solution was then added dropwise to the P123-containing alcohol solution. The mixture was stirred at room temperature for 30 minutes, allowed to stand at 100°C for 12 hours, washed five times with ethanol, centrifuged, and dried overnight at 120°C. The powder sample was then calcined in air (oxygen content 21%) at 600°C for 12 hours to obtain a cobalt-containing cerium oxide sample. Subsequently, an aqueous solution of ruthenium nitrite was impregnated into the cobalt-containing cerium oxide sample, and the sample was carbonized in pure CO gas at 500°C for 6 hours. Then, it was reduced in pure hydrogen at 450°C for 6 hours to obtain a cerium oxide-supported ruthenium metal catalyst with a ruthenium mass percentage of 2.5 wt%.

[0030] Comparative Example 5: 5 mL of concentrated nitric acid was added to 5 mL of deionized water to obtain an acid-water mixture. Cerium nitrate and cobalt nitrate were then added to this acid-water mixture and stirred until dissolved, yielding an acid-water solution containing cerium and cobalt. 2 g of P123 was added to 100 mL of n-butanol and stirred to obtain an alcoholic solution containing P123. The acid-water solution containing cerium and cobalt was then added dropwise to the alcoholic solution containing P123. The mixture was stirred at room temperature for 30 minutes, allowed to stand at 100°C for 12 hours, washed five times with ethanol, centrifuged, and dried overnight at 120°C. The powder sample was then calcined in air (oxygen content 21%) at 600°C for 12 hours to obtain a cobalt-containing cerium oxide sample. This cobalt-containing cerium oxide sample was then carbonized in pure CO gas at 500°C for 6 hours, followed by reduction in pure hydrogen at 450°C for 6 hours to obtain the cerium oxide-supported cobalt metal catalyst, with a cobalt mass percentage of 2.5 wt%.

[0031] Figure 1 The figures show the DRIFTS spectra of CO adsorption at 50 °C for three catalysts: Comparative Example 1, Comparative Example 4, and Example 1. As can be seen from the figures, the catalyst containing only Ru metal (Comparative Example 4) shows high adsorption values ​​at 1982, 2051, 2124, and 2172 cm⁻¹. -1 There are four CO adsorption peaks, which belong to Ru atoms that interact with oxygen atoms. 0 CO adsorbed on metal, CO species linearly adsorbed on Ru particles, CO adsorbed on Ru n+ The peaks of tricarbonyl species and gaseous CO were observed. In Comparative Example 1, the addition of cobalt metal had no effect on the CO adsorption properties of ruthenium, while the corresponding infrared spectral characteristic peaks of CO species linearly adsorbed on metal Ru particles in the catalyst obtained in Example 1 were red-shifted to 2062 cm⁻¹. -1 This indicates that the preparation method of the cerium oxide-supported ruthenium-cobalt bimetallic catalyst of the present invention will change the electronic properties of ruthenium, which will improve the ammonia decomposition performance of the catalyst.

[0032] When WO3 powder reacts with hydrogen atoms, it forms H. x WO3 exhibits a noticeable color change; however, its reaction with hydrogen typically requires temperatures above 400°C. Therefore, heat treatment of a mixture of catalyst and WO3 powder in a hydrogen atmosphere allows for the detection of changes in the ability of hydrogen atoms to transfer from the catalyst surface to the WO3 powder and react with it. Figure 2The figure shows a comparison of the color changes of the mixture of catalyst and WO3 (mass ratio of catalyst to WO3 powder 1:30) obtained in Example 1 and Comparative Example 1 after hydrogen treatment at 80 °C for different times. As can be seen from the figure, although the catalyst formulations of Example 1 and Comparative Example 1 are similar, the sample of Example 1 showed a distinct deep blue color after 5 minutes of treatment, indicating that the hydrogen atoms on the surface of the sample of Example 1 have a stronger ability to migrate towards WO3. This is beneficial for the diffusion and removal of hydrogen components generated during ammonia decomposition from the active sites.

[0033] The ammonia decomposition activity of the catalyst was tested in a fixed-bed quartz tube reactor. Pure ammonia was used as the feed gas, and the catalyst was pre-reduced at 500℃ for 2 hours. The test space velocity was 5000 mL g. -1 h -1 The activity of the catalyst is expressed as the NH3 conversion rate, where the ammonia conversion rate = (ammonia content at reactor inlet - ammonia content at reactor outlet) / ammonia content at reactor inlet × 100%. The activity evaluation results are shown in Table 1.

[0034] Table 1

[0035] As can be seen from Table 1, under the same conditions, the ammonia decomposition activity of the cerium oxide-supported cobalt-ruthenium bimetallic catalyst obtained in this invention is higher than that of other comparative catalysts, proving that it has good ammonia decomposition catalytic activity and has good application prospects.

[0036] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of protection of the present invention should be included in the scope of the present invention.

Claims

1. A cerium oxide-supported ruthenium-cobalt bimetallic catalyst for ammonia decomposition, characterized in that, The catalyst consists of a cerium oxide support and two active components, ruthenium and cobalt, with the active metal ruthenium having a mass percentage of 0.5-3.0 wt% and the active metal cobalt having a mass percentage of 0.2-1.5 wt%.

2. The method for preparing the cerium oxide-supported ruthenium-cobalt bimetallic catalyst according to claim 1, characterized in that, Including the following steps: 1) Mix concentrated nitric acid and deionized water to obtain an acid-water mixture; 2) Add the cerium salt precursor and cobalt precursor to the acidic aqueous mixture and stir until completely dissolved to obtain an acidic aqueous mixture containing cerium and cobalt; 3) Add nonionic surfactant P123 to alcohol solvent and stir to obtain an alcohol solution containing P123; 4) The acidic aqueous solution containing cerium and cobalt obtained in step 2) is added dropwise to the alcoholic solution containing P123 obtained in step 3), and the mixture is stirred, aged, washed, centrifuged and dried to obtain a powder sample; 5) Calcine the powder sample obtained in step 4) in an oxygen-containing gas; 6) The sample obtained in step 5) is immersed in a ruthenium precursor alcohol solution to introduce the ruthenium active component; 7) The sample obtained in step 6) is carbonized and reduced in a carbon-containing gas to obtain a cerium oxide-supported ruthenium-cobalt bimetallic catalyst.

3. The method for preparing a cerium oxide-supported ruthenium-cobalt bimetallic catalyst for ammonia decomposition as described in claim 2, characterized in that, In step 1), the volume ratio of concentrated nitric acid to deionized water is 0.8-2:

1.

4. The method for preparing a cerium oxide-supported ruthenium-cobalt bimetallic catalyst for ammonia decomposition as described in claim 2, characterized in that, In step 2), the cerium salt precursor is one of cerium nitrate, cerium acetate, and cerium chloride, and the cobalt precursor is one of cobalt nitrate, cobalt chloride, cobalt acetate, and cobalt oxalate.

5. The method for preparing a cerium oxide-supported ruthenium-cobalt bimetallic catalyst for ammonia decomposition as described in claim 2, characterized in that, In step 3), the alcohol solvent is one of ethanol, n-butanol, isopropanol, and n-propanol.

6. The method for preparing a cerium oxide-supported ruthenium-cobalt bimetallic catalyst for ammonia decomposition as described in claim 2, characterized in that, In step 3), the concentration of P123 in the alcohol solution containing P123 is 15-60 mg / mL.

7. The method for preparing a cerium oxide-supported ruthenium-cobalt bimetallic catalyst for ammonia decomposition as described in claim 2, characterized in that, In step 4), the aging process involves standing at 35-120°C for 3-24 hours; the washing solution used is methanol or ethanol.

8. The method for preparing a cerium oxide-supported ruthenium-cobalt bimetallic catalyst for ammonia decomposition as described in claim 2, characterized in that, In step 5), the oxygen volume content in the oxygen-containing gas is 20-100%; the calcination temperature is 500-1000℃; and the treatment time is 2-48 hours.

9. The method for preparing a cerium oxide-supported ruthenium-cobalt bimetallic catalyst for ammonia decomposition as described in claim 2, characterized in that, In step 6), the ruthenium precursor is one of ruthenium nitrite, ruthenium acetylacetonate, or ruthenium acetate; the ruthenium precursor is dried at 60-110°C for 0.2-5 hours before the preparation of the ruthenium precursor alcohol solution; the solvent in the alcohol solution is methanol or ethanol.

10. The method for preparing a cerium oxide-supported ruthenium-cobalt bimetallic catalyst for ammonia decomposition as described in claim 2, characterized in that, In step 7), the carbon-containing gas is a mixture of CO, CH4, C2H6 and nitrogen or an inert gas, wherein the volume content of the carbon-containing gas is 20-100%; the carbonization temperature is 400-700℃, and the treatment time is 1-20 hours; the reduction is performed in a hydrogen-containing gas at 200-600℃ for 0.5-24 hours, wherein the volume ratio of hydrogen in the hydrogen-containing gas is 5%-100%.

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