Supported ruthenium-based ammonia synthesis catalyst prepared from organic matter modified activated carbon

Abstract

The invention discloses a supported ruthenium-based ammonia synthesis catalyst prepared from organic matter modified activated carbon, which is prepared by taking the organic matter modified activated carbon as a carrier, and dipping the organic matter modified activated carbon into a ruthenium salt solution and a barium salt solution in sequence. Compared with an activated carbon supported ruthenium catalyst prepared by a traditional impregnation method, the obtained catalyst has the advantages that the ammonia synthesis activity of the catalyst with low ruthenium loading capacity is improved, and the catalyst has a relatively good application prospect.

Description

Technical Field

[0001] The present invention belongs to the field of ammonia synthesis, and particularly relates to a supported ruthenium-based ammonia synthesis catalyst prepared by modifying activated carbon with an organic substance. Background Art

[0002] Ammonia is one of the most widely produced and applied chemicals globally. More than 80% of ammonia is used in the production of chemical fertilizers, and a small amount is used in the chemical industry. With the drive of energy conservation and emission reduction policies and the adjustment of energy supply and use structures under the background of "dual carbon", the consumption attribute of ammonia is shifting towards a hydrogen storage carrier and a clean fuel. It can be seen that the importance of ammonia synthesis in industrial production is self-evident. Therefore, in the field of ammonia synthesis, developing high-performance catalysts under mild conditions is a key research direction.

[0003] In the research of ammonia synthesis catalysts, selecting a suitable carrier is a key factor in achieving high metal dispersion, making full use of the surface of metal particles, and reducing the usage of expensive metals. Activated carbon has a rich pore structure and a large specific surface area, which can effectively improve the utilization rate of active metal components and is an ideal carrier for Ru-based catalysts. Appropriate modification of the carbon-supported ruthenium catalyst can usually improve the performance of the ruthenium catalyst. For example, in patent CN 110813359A, it is reported that during the catalyst preparation process, a nitrogen-containing porous carbon carrier is prepared using zinc nitrate hexahydrate, 2-methylimidazole, N,N-dimethylformamide, etc., and then it is added to an ethanol solution of a polyvinylpyrrolidone-ruthenium precursor, and finally a ruthenium-based catalyst with nitrogen-doped porous carbon as the carrier is prepared, and this method improves the ammonia synthesis activity. Although the existing Ru catalysts supported on graphitized activated carbon have achieved certain success in industrial applications, due to defects such as the low abundance of ruthenium in nature, high application costs, and susceptibility to hydrogen poisoning, their widespread application is limited. Therefore, improving the activity of low-ruthenium-content catalysts has become the focus of current research.

[0004] During the research process, researchers found that Ru in the catalyst may exist in the form of metallic ruthenium (Ru 0 ) and ruthenium oxide (Ru n+ ). Through some means, the ratio of Ru 0 to Ru n+ in the Ru-based catalyst can reach the optimal range, thereby increasing the exposure amount of Ru and improving the metal utilization rate. Li et al. (Arming Ru with Oxygen-Vacancy-EnrichedRuO 2Sub-Nanometer Skin Activates Superior Bifunctionality for pH-Universal Overall Water Splitting [J]. Advanced Materials, 2023, 35(24): 2206351). Through Ru 3 + -melamine precursors are calcined at high temperature in an inert gas to form Ru / C hybrid microplates, and then a sub-nanometer skin rich in RuO is coated on the Ru surface to obtain the final product. During this process, Ru 2 -melamine precursors are formed through the electrostatic interaction between the N atoms in melamine molecules and Ru 3+ ions. Then, due to the "self-templating" of melamine crystals, carbothermal reduction forms carbon-based hybrid microplates modified by dense Ru nanoclusters. Although this method is instructive, it is not conducive to the application of Ru catalysts with B 3+ as the active site in ammonia synthesis. 5 Summary of the Invention

[0005] The purpose of the present invention is to provide a supported ruthenium-based ammonia synthesis catalyst prepared by modifying activated carbon with an organic substance. Compared with the traditional activated carbon-supported ruthenium-based catalyst obtained through impregnation and hydrogen treatment, the catalyst obtained in the present invention has significantly improved catalytic activity and stability, and has good application prospects.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions: A supported ruthenium-based ammonia synthesis catalyst prepared by modifying activated carbon with an organic substance, which is composed of activated carbon modified with an organic substance as the carrier, ruthenium as the active component, and barium as the promoter; wherein, the organic substance is any one of polyvinylpyrrolidone and L-ascorbic acid.

[0007] The preparation method of the supported ruthenium-based ammonia synthesis catalyst includes the following steps: 1) Add activated carbon and an organic substance to a solvent, stir and mix at room temperature, then let it stand overnight, and then centrifuge, wash, and dry; 2) Place the sample prepared in step 1) in an acid solution, stir and mix evenly at room temperature, then centrifuge and wash until neutral, and finally dry to obtain activated carbon modified with an organic substance; 3) Impregnate the activated carbon modified with an organic substance obtained in step 2) with a ruthenium salt solution, and then perform high-temperature treatment in an inert atmosphere; 4) Impregnate the sample obtained in step 3) with a barium salt solution, and then dry and reduce it to obtain the supported ruthenium-based ammonia synthesis catalyst.

[0008] Further, the mass ratio of the organic matter to the activated carbon used in step 1) is 0.01:1 - 1:1.

[0009] Further, the solvent in step 1) is one of deionized water, methanol, and ethanol.

[0010] Further, the acid solution in step 2) is a deionized water, methanol, or ethanol solution of any one of nitric acid, hydrochloric acid, and acetic acid, and its concentration is 0.1 - 5 mol / L.

[0011] Further, the ruthenium salt solution in step 3) is a deionized water, methanol, or ethanol solution of any one of ruthenium nitrosyl nitrate, ruthenium acetylacetonate, and ruthenium trichloride.

[0012] Further, the dosage of the ruthenium salt solution in step 3) is converted according to the mass ratio of ruthenium to activated carbon therein being 0.001:1 - 0.1:1.

[0013] Further, the inert atmosphere in step 3) is one or more of nitrogen and group 0 gases.

[0014] Further, the temperature of the high-temperature treatment in step 3) is 300 - 1000 °C, and the time is 0.5 - 6 hours.

[0015] Further, the barium salt solution in step 4) is an aqueous solution of any one of barium nitrate and barium oxalate.

[0016] Further, the dosage of the barium salt solution in step 4) is converted according to the mass ratio of barium to activated carbon therein being 0.001:1 - 0.1:1.

[0017] Further, the reduction in step 4) is carried out in a hydrogen-containing gas environment at 200 - 600 °C for 0.2 - 48 hours.

[0018] Furthermore, the hydrogen-containing gas is a mixture of hydrogen and nitrogen or group 0 gases, and the volume content of hydrogen therein is 1% - 100%.

[0019] Remarkable advantages of the present invention: The present invention provides a supported ruthenium catalyst for ammonia synthesis modified with an organic matter on activated carbon, which is prepared by using activated carbon modified with an organic matter as a carrier and successively introducing a ruthenium active component and a barium promoter. Compared with the ruthenium catalyst supported on activated carbon prepared by the traditional impregnation method, this catalyst has higher ammonia synthesis activity and good application prospects. Description of the drawings

[0020] Figure 1 STEM-HAADF, Mapping, and Ru particle size distribution diagrams of the catalysts obtained in Example 1 and Comparative Example 1.

[0021] Figure 2 Mass spectrometry signal diagrams of the catalysts obtained in Example 1 and Comparative Example 1 in the H / D exchange experiment at 50 °C.

[0022] Figure 3 For the comparison diagram of the color changes of the mixture of the catalysts obtained in Example 1 and Comparative Example 1 and WO 3 under different hydrogen treatment times. Detailed implementation manners

[0023] A supported ruthenium-based ammonia synthesis catalyst prepared by modifying activated carbon with an organic substance, and its preparation method includes the following steps: 1) Add the organic substance and activated carbon to a solvent according to a mass ratio of 0.01:1 - 1:1, stir and mix at room temperature, let stand overnight, then centrifuge, wash, and dry; 2) Place the sample prepared in step 1) in an acid solution with a concentration of 0.1 - 5 mol / L, stir and mix evenly at room temperature, then centrifuge and wash until neutral, and finally dry to obtain the activated carbon modified with the organic substance; 3) Impregnate the activated carbon modified with the organic substance obtained in step 2) with a ruthenium salt solution, and then perform high-temperature treatment at 300 - 1000 °C for 0.5 - 6 hours in an inert atmosphere; 4) Impregnate the sample obtained in step 3) with a barium salt solution, and then reduce it in a hydrogen-containing gas environment at 200 - 600 °C for 0.2 - 48 hours after drying to obtain a supported ruthenium-based ammonia synthesis catalyst, wherein the ruthenium content is 0.1% - 10% of the mass of the activated carbon, and the barium content is 0.1% - 10% of the mass of the activated carbon.

[0024] Among them, the organic substance in step 1) is any one of polyvinylpyrrolidone and L-ascorbic acid. The solvent is one of deionized water, methanol, and ethanol.

[0025] The acid solution in step 2) is a deionized water, methanol, or ethanol solution of any one of nitric acid, hydrochloric acid, and acetic acid.

[0026] The ruthenium salt solution in step 3) is a deionized water, methanol, or ethanol solution of any one of ruthenium nitrosyl nitrate, ruthenium acetylacetonate, and ruthenium trichloride. The inert atmosphere is one or more of nitrogen and Group 0 gases.

[0027] The barium salt solution in step 4) is an aqueous solution of any one of barium nitrate and barium oxalate. The hydrogen-containing gas is a mixture of hydrogen and nitrogen or Group 0 gases, and the volume content of hydrogen is 1% - 100%.

[0028] The gas flow rate in the operation is 20 - 1000 mL / min.

[0029] To make the content of the present invention easier to understand, the technical solutions of the present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited thereto.

[0030] Example 1: 1) Mix activated carbon and polyvinylpyrrolidone in a mass ratio of 1:1 and place them in 50 mL of methanol. Stir at room temperature for 1 hour, then let it stand overnight. Then centrifuge at a speed of 10000 rmp for 5 minutes to remove the solution, and leave the solid to dry. 2) Place the solid obtained in step 1) in a methanol solution of 5 mol / L nitric acid, stir at room temperature for 5 minutes, then centrifuge at a speed of 10000 rpm for 3 minutes. Then wash with methanol until neutral, and finally dry to obtain polyvinylpyrrolidone-modified activated carbon. 3) Impregnate the polyvinylpyrrolidone-modified activated carbon obtained in step 2) with a methanol solution of 2 wt% ruthenium nitrosyl nitrate by the equal-volume impregnation method. After drying, calcine in pure nitrogen (gas flow rate is 150 mL / min) at 950 °C for 3 hours. 4) Impregnate the sample obtained in step 3) with an aqueous solution of 6 wt% barium nitrate. After drying, reduce it in pure hydrogen (gas flow rate is 150 mL / min) at 500 °C for 8 hours to obtain Ba-(2Ru / AC-PVP) N , where the ruthenium content is 2% of the mass of the activated carbon, and the barium content is 6% of the mass of the activated carbon.

[0031] Example 2: 1) Mix activated carbon and L-ascorbic acid in a mass ratio of 1:1 and place them in 50 mL of methanol. Stir at room temperature for 1 hour, then let it stand overnight. Then centrifuge at a speed of 10000 rmp for 5 minutes to remove the solution, and leave the solid to dry. 2) Place the solid obtained in step 1) in a methanol solution of 5 mol / L nitric acid, stir at room temperature for 5 minutes, then centrifuge at a speed of 10000 rpm for 3 minutes. Then wash with methanol until neutral, and finally dry to obtain L-ascorbic acid-modified activated carbon. 3) Impregnate the L-ascorbic acid-modified activated carbon obtained in step 2) with a methanol solution of 2 wt% ruthenium nitrosyl nitrate by the equal-volume impregnation method. After drying, calcine in pure nitrogen (gas flow rate is 150 mL / min) at 950 °C for 3 hours. 4) Impregnate the sample obtained in step 3) with an aqueous solution of 6 wt% barium nitrate. After drying, reduce it in pure hydrogen (gas flow rate is 150 mL / min) at 500 °C for 8 hours to obtain the final catalyst, where the ruthenium content is 2% of the mass of the activated carbon, and the barium content is 6% of the mass of the activated carbon.

[0032] Example 3: 1) Mix activated carbon and polyvinylpyrrolidone in a mass ratio of 2:1, place them in 50 mL of methanol, stir at room temperature for 1 hour, then let it stand overnight, and then centrifuge at a speed of 10000 rmp for 5 minutes to remove the solution, leaving the solid to dry; 2) Place the solid obtained in step 1) in a methanol solution of 5 mol / L nitric acid, stir at room temperature for 5 minutes, then centrifuge at a speed of 10000 rpm for 3 minutes, then wash with methanol until neutral, and finally dry to obtain polyvinylpyrrolidone-modified activated carbon; 3) Impregnate the polyvinylpyrrolidone-modified activated carbon obtained in step 2) with a methanol solution of 2 wt% ruthenium nitrosyl nitrate by the equal-volume impregnation method, dry, and then calcine in pure nitrogen (gas flow rate is 150 mL / min) at 950 °C for 3 hours; 4) Impregnate the sample obtained in step 3) with an aqueous solution of 6 wt% barium nitrate, dry, and then reduce in pure hydrogen (gas flow rate is 150 mL / min) at 500 °C for 8 hours to obtain the final catalyst, in which the ruthenium content is 2% of the mass of the activated carbon and the barium content is 6% of the mass of the activated carbon.

[0033] Example 4: 1) Mix activated carbon and polyvinylpyrrolidone in a mass ratio of 4:1, place them in 50 mL of methanol, stir at room temperature for 1 hour, then let it stand overnight, and then centrifuge at a speed of 10000 rmp for 5 minutes to remove the solution, leaving the solid to dry; 2) Place the solid obtained in step 1) in a methanol solution of 5 mol / L nitric acid, stir at room temperature for 5 minutes, then centrifuge at a speed of 10000 rpm for 3 minutes, then wash with methanol until neutral, and finally dry to obtain polyvinylpyrrolidone-modified activated carbon; 3) Impregnate the polyvinylpyrrolidone-modified activated carbon obtained in step 2) with a methanol solution of 2 wt% ruthenium nitrosyl nitrate by the equal-volume impregnation method, dry, and then calcine in pure nitrogen (gas flow rate is 150 mL / min) at 950 °C for 3 hours; 4) Impregnate the sample obtained in step 3) with an aqueous solution of 6 wt% barium nitrate, dry, and then reduce in pure hydrogen (gas flow rate is 150 mL / min) at 500 °C for 8 hours to obtain the final catalyst, in which the ruthenium content is 2% of the mass of the activated carbon and the barium content is 6% of the mass of the activated carbon.

[0034] Example 5: 1) Mix activated carbon and polyvinylpyrrolidone in a mass ratio of 8:1, place them in 50 mL of methanol, stir at room temperature for 1 hour, then let it stand overnight, and then centrifuge at a speed of 10000 rmp for 5 minutes to remove the solution, leaving the solid to dry; 2) Place the solid obtained in step 1) in a methanol solution of 5 mol / L nitric acid, stir at room temperature for 5 minutes, then centrifuge at 10000 rpm for 3 minutes, then wash with methanol until neutral, and finally dry to obtain polyvinylpyrrolidone-modified activated carbon; 3) Impregnate the polyvinylpyrrolidone-modified activated carbon obtained in step 2) with a methanol solution of 2 wt% ruthenium nitrosyl nitrate by the equal-volume impregnation method, dry, and then calcine in pure nitrogen (gas flow rate: 150 mL / min) at 950 °C for 3 hours; 4) Impregnate the sample obtained in step 3) with an aqueous solution of 6 wt% barium nitrate, dry, and then reduce in pure hydrogen (gas flow rate: 150 mL / min) at 500 °C for 8 hours to obtain the final catalyst, in which the ruthenium content is 2% of the mass of the activated carbon and the barium content is 6% of the mass of the activated carbon.

[0035] Comparative Example 1: 1) Impregnate activated carbon with an aqueous solution of 2 wt% ruthenium nitrosyl nitrate by the equal-volume impregnation method, dry, and then calcine in pure hydrogen (gas flow rate: 150 mL / min) at 500 °C for 2 hours; 2) Impregnate the sample obtained in step 1) with an aqueous solution of 6 wt% barium nitrate, dry, and then reduce in pure hydrogen (gas flow rate: 150 mL / min) at 500 °C for 8 hours to obtain Ba-(2Ru / AC) H , in which the ruthenium content is 2% of the mass of the activated carbon and the barium content is 6% of the mass of the activated carbon.

[0036] Comparative Example 2: 1) Mix activated carbon and polyvinylpyrrolidone in a mass ratio of 1:1, place them in 50 mL of methanol, stir at room temperature for 1 hour, then let stand overnight, then centrifuge at 10000 rmp for 5 minutes, remove the solution, and leave the solid to dry; 2) Place the solid obtained in step 1) in a methanol solution of 5 mol / L nitric acid, stir at room temperature for 5 minutes, then centrifuge at 10000 rpm for 3 minutes, then wash with methanol until neutral, and finally dry to obtain polyvinylpyrrolidone-modified activated carbon; 3) Impregnate the polyvinylpyrrolidone-modified activated carbon obtained in step 2) with a methanol solution of 2 wt% ruthenium nitrosyl nitrate by the equal-volume impregnation method, and dry; 4) Impregnate the sample obtained in step 3) with an aqueous solution of 6 wt% barium nitrate, dry, and then reduce in pure hydrogen (gas flow rate: 150 mL / min) at 500 °C for 8 hours to obtain Ba-2Ru / AC-PVP, in which the ruthenium content is 2% of the mass of the activated carbon and the barium content is 6% of the mass of the activated carbon.

[0037] Comparative Example 3: 1) The activated carbon was impregnated with a methanol solution of 2 wt% ruthenium nitrosyl nitrate by the equal-volume impregnation method and dried; 2) The sample prepared in step 1) was mixed with polyvinylpyrrolidone and placed in 50 mL of methanol (the amount of polyvinylpyrrolidone was added according to the mass ratio of activated carbon to polyvinylpyrrolidone of 1:1). After stirring at room temperature for 1 hour, it was left standing overnight, and then centrifuged at 10000 rmp for 5 minutes to remove the solution, and the solid was left to dry; 3) The solid obtained in step 2) was placed in a methanol solution of 5 mol / L nitric acid, stirred at room temperature for 5 minutes, then centrifuged at 10000 rpm for 3 minutes, and then washed with methanol until neutral, and finally dried; 4) The sample obtained in step 3) was calcined in pure nitrogen (gas flow rate of 150 mL / min) at 950 °C for 3 hours; 5) The sample obtained in step 4) was impregnated with an aqueous solution of 6 wt% barium nitrate, dried, and then reduced in pure hydrogen (gas flow rate of 150 mL / min) at 500 °C for 8 hours to obtain Ba-(PVP-2Ru / AC) N , where the ruthenium content was 2% of the mass of the activated carbon, and the barium content was 6% of the mass of the activated carbon.

[0038] Comparative Example 4: 1) 0.479 g of ruthenium nitrosyl nitrate was mixed with 2 g of polyvinylpyrrolidone and placed in 50 mL of methanol. Subsequently, the solvent was removed by heating to 110 °C under stirring, and it was naturally cooled to room temperature to obtain a Ru-PVP precursor; 2) The precursor obtained in step 1) was dispersed in 50 mL of methanol, 2 g of activated carbon was added, and the mixture was stirred at room temperature for 1 h and then left standing overnight. Then, it was centrifuged at 10000 rmp for 5 minutes to remove the solution, and the solid was left to dry; 3) The solid prepared in step 2) was placed in a methanol solution of 5 mol / L nitric acid, stirred at room temperature for 5 minutes, then centrifuged at 10000 rpm for 3 minutes, and then washed until neutral and finally dried; 4) The sample obtained in step 3) was calcined in pure nitrogen (gas flow rate of 150 mL / min) at 950 °C for 3 hours; 5) The sample obtained in step 4) was impregnated with an aqueous solution of 6 wt% barium nitrate, dried, and then reduced in pure hydrogen (gas flow rate of 150 mL / min) at 500 °C for 8 hours to obtain the final catalyst, where the ruthenium content was 2% of the mass of the activated carbon, and the barium content was 6% of the mass of the activated carbon.

[0039] Figure 1STEM-HAADF, Mapping, and Ru particle size distribution diagrams of the catalysts obtained in Example 1 and Comparative Example 1. As can be seen from the figure, in the catalyst obtained in Comparative Example 1, most of the Ru exists in the form of nanoparticles and atomic clusters with a lattice structure, and the average particle size is about 1.97 nm, and Ba is distributed near Ru. In the catalyst obtained in Example 1, a small amount of Ru exists as single atoms, mostly atomic clusters and particles, and the average particle size is about 1.72 nm, and Ba is evenly distributed on the support. At the same time, there is aggregation or overlap of Ru in the catalyst of Comparative Example 1, while the distribution of Ru in the catalyst of Example 1 is more dispersed. Therefore, more active sites of Ru can be exposed, which is beneficial to ammonia synthesis.

[0040] Figure 2 Mass spectrometry signal diagrams of the catalysts obtained in Example 1 and Comparative Example 1 in the H / D exchange experiment at 50 °C (the catalyst is switched from Ar gas to 50% H 2 -50% D 2 mixed gas, and the signals of m / z = 2, 3, and 4 are detected by a mass spectrometer during this process). It can be obtained from the figure that when the gas is switched to 50% H 2 -50% D 2 mixed gas, the signal of m / z = 3 of the catalyst obtained in Example 1 appears faster, and the intensity ratio in the stage of 12 - 15 min is higher than that of Comparative Example 1, indicating that the hydrogen species adsorbed on the catalyst of Example 1 have stronger activation and exchange abilities.

[0041] WO 3 reduction will form blue H x WO 3 , which can be used as an indicator for detecting H. For this reason, after mixing the catalyst and WO 3 powder in a mass ratio of 1:30 and introducing H 2 at 100 °C, observe the color change to explore the hydrogen migration on the catalyst surface. Figure 3 Color change comparison diagrams of the mixtures of the catalysts obtained in Example 1 and Comparative Example 1 and WO 3 under different hydrogen treatment times. As can be seen from the figure, the catalyst obtained in Example 1 turns significantly blue at 10 min, while Comparative Example 1 only shows green; at 20 min, the catalyst obtained in Example 1 completely turns dark blue, while the color of Comparative Example 1 is relatively lighter, indicating that the hydrogen atoms on the surface of Ru in the catalyst obtained in Example 1 have a faster migration ability to WO 3 .

[0042] The catalytic activities of the catalysts obtained in the examples and comparative examples were evaluated in a high-pressure activity test device. The specific operation was to mix 0.3 g of the catalyst with quartz sand and pack it in the isothermal zone of the reactor. The reaction gas was a nitrogen-hydrogen mixture obtained by high-temperature catalytic cracking of ammonia, and the hydrogen-nitrogen ratio was 3:1. The reaction conditions were: pressure 1 MPa, reaction temperature 400 °C, and reaction space velocity 36000 cm 3 g -1 h -1 . The results of the catalytic activity measurement are shown in Table 1.

[0043] Table 1 Comparison of the performance of the catalysts obtained in the examples and comparative examples

[0044] As can be seen from Table 1, when the Ru loading was 2 wt% in both cases, the catalyst prepared in the example had a higher ammonia synthesis activity. At the same time, appropriate organic species and content were also key factors for obtaining high ammonia synthesis activity. In contrast, the ruthenium catalyst prepared by the traditional method (Comparative Example 1) had a lower ammonia synthesis rate.

[0045] The above are only the preferred embodiments of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

Claims

1. A supported ruthenium-based ammonia synthesis catalyst prepared by organic modified activated carbon, characterized in that: The catalyst is composed of activated carbon modified by organic matter as a carrier, ruthenium as an active component and barium as an auxiliary agent; the organic matter is any one of polyvinyl pyrrolidone and L-ascorbic acid.

2. A method for preparing a supported ruthenium-based ammonia synthesis catalyst as claimed in claim 1, characterized in that: The following steps are involved: 1) Add activated carbon and organic matter into the solvent, stir and mix at room temperature, let stand overnight, then centrifuge, wash and dry; 2) placing the sample prepared in step 1) in an acid solution, stirring and mixing at room temperature, centrifuging, washing to neutrality, and finally drying to obtain organic-modified activated carbon; The organic-modified activated carbon obtained in step 2) is impregnated with a ruthenium salt solution, and then subjected to high-temperature treatment in an inert atmosphere; 4) The sample obtained in step 3) is impregnated with a barium salt solution, and then dried and reduced to obtain the supported ruthenium-based ammonia synthesis catalyst.

3. The method for preparing a supported ruthenium-based ammonia synthesis catalyst according to claim 2, characterized in that: The mass ratio of the organic matter to the activated carbon used in step 1) is 0.01:1-1:

1.

4. The method for preparing a supported ruthenium-based ammonia synthesis catalyst according to claim 2, characterized in that: Step 1) The solvent is one of deionized water, methanol and ethanol.

5. The method for preparing a supported ruthenium-based ammonia synthesis catalyst according to claim 2, characterized in that: Step 2) The acid solution is any one of nitric acid, hydrochloric acid and acetic acid in deionized water, methanol or ethanol, and its concentration is 0.1-5 mol / L.

6. The method for preparing a supported ruthenium-based ammonia synthesis catalyst according to claim 2, characterized in that: Step 3) The ruthenium salt solution is a deionized water, methanol or ethanol solution of any one of ruthenium nitrosyl nitrate, ruthenium acetylacetonate and ruthenium trichloride, and the amount thereof is converted according to the mass ratio of ruthenium to activated carbon of 0.001:1-0.1:

1.

7. The method for preparing a supported ruthenium-based ammonia synthesis catalyst according to claim 2, characterized in that: Step 3) The inert atmosphere is one or more of nitrogen and Group 0 gases.

8. The method for preparing a supported ruthenium-based ammonia synthesis catalyst according to claim 2, characterized in that: Step 3) The temperature of the high temperature treatment is 300-1000°C and the time is 0.5-6 hours.

9. The method for preparing a supported ruthenium-based ammonia synthesis catalyst according to claim 2, characterized in that: Step 4) The barium salt solution is an aqueous solution of either barium nitrate or barium oxalate, and the amount thereof is converted according to the mass ratio of barium to activated carbon of 0.001:1-0.1:

1.

10. The method for preparing a supported ruthenium-based ammonia synthesis catalyst according to claim 2, characterized in that: Step 4) The reduction is carried out in a hydrogen-containing gas environment at 200-600° C. for 0.2-48 hours; the hydrogen-containing gas is a mixture of hydrogen and nitrogen or a Group 0 gas, wherein the volume content of hydrogen is 1%-100%.

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