Ruthenium-based catalyst, preparation method thereof and application of ruthenium-based catalyst in hydrogen production through ammonia decomposition

Abstract

The invention discloses a ruthenium-based catalyst, a preparation method of the ruthenium-based catalyst and application of the ruthenium-based catalyst in hydrogen production through ammonia decomposition. The ruthenium-based catalyst comprises a carrier and an active component loaded on the carrier, the carrier is CeO2; the active component is metal ruthenium, and ruthenium atoms are dispersed on the surface of CeO2 in a monatomic form. The chemical interaction between the oxide carrier and Ru is utilized, so that Ru is dispersed on the surface of CeO2 in an atomic scale, the loading capacity of metal Ru in a traditional Ru-based catalyst is effectively reduced, and the atom utilization rate of precious metal is increased. The Ru monatomic catalyst can be used in the process of hydrogen production through ammonia decomposition, and ammonia gas (the chemical formula is NH3) is catalyzed to be decomposed to produce nitrogen (the chemical formula is N2) and hydrogen (the chemical formula is H2) under the condition of high temperature. The catalyst is simple in preparation method, high in stability and low in cost, and has a wide application prospect in the field of hydrogen energy utilization such as ammonia decomposition hydrogen refueling stations.

Description

Technical Field

[0001] The present application relates to a ruthenium-based catalyst, a preparation method thereof, and an application thereof in ammonia decomposition for hydrogen production, belonging to the field of hydrogen energy utilization materials. Background Art

[0002] The use of fossil energy has led to a large amount of carbon dioxide (chemical formula: CO2) emissions, causing environmental problems such as the greenhouse effect, glacier melting, and seawater acidification, threatening the living environment of humans and other organisms. To achieve the sustainable development of human society, the world is actively seeking solutions. China officially put forward the "dual carbon" goal in September 2020, that is, striving to achieve carbon peak before 2030 and carbon neutrality before 2060. As a clean, efficient, and pollution-free green energy, hydrogen energy will occupy an important position in the future energy system. However, hydrogen (H2) has a low density and a wide explosion limit (4% - 75%), and currently, its storage and transportation face technical bottlenecks and safety hazards. In recent years, ammonia (NH3) as an emerging energy carrier, with a hydrogen mass content as high as 17.6%, is easy to transport and store, and does not produce carbon oxides after decomposition, making it an ideal hydrogen storage material. Therefore, studying the in-situ ammonia decomposition for hydrogen production process is of great significance for the effective utilization of hydrogen energy.

[0003] Each mole of ammonia can generate 0.5 mol of N2 and 1.5 mol of H2 after decomposition. Thermodynamically, the ammonia decomposition for hydrogen production reaction is an endothermic process. Therefore, to fully convert ammonia, a reaction temperature of 400 - 700 °C is usually required. Currently, for the catalytic ammonia decomposition for hydrogen production reaction process, oxide-supported Ru-based catalysts have the best catalytic activity. However, ruthenium is a precious metal with scarce resources. The key to reducing the cost of Ru-based ammonia decomposition for hydrogen production catalysts lies in reducing the loading amount of metallic Ru and improving the atomic utilization rate of Ru.

[0004] As a catalyst with 100% atomic utilization rate, single-atom catalysts have shown high activity in many chemical reactions such as carbon monoxide oxidation, selective hydrogenation of organic compounds, and reductive amination of aldehydes and ketones. On the surface of single-atom catalysts, the active components are dispersed in atomic form on the surface of the support, enabling the active components to come into full contact with the reactants, greatly improving the atomic utilization efficiency of the active components. Therefore, selecting a suitable support and preparing an atomically dispersed Ru-based catalyst for ammonia decomposition for hydrogen production reaction is an effective way to improve the utilization rate of precious metal Ru. (Accounts of Chemical Research, 2013, 46(8), 1740 - 1748, doi: 10.1021 / ar300361m)

[0005] China is a major country in rare earth resources. Among them, the oxide of cerium element is most commonly cerium dioxide (CeO2). CeO2 has the characteristics of high hardness, stable structure, high temperature resistance, etc., and is used in the manufacture of semiconductors, polishing materials, catalyst carriers, etc. On the other hand, the O atoms in CeO2 will leave the lattice under high temperature conditions to form an oxygen vacancy defect structure. This defect structure is conducive to the dispersion of noble metal species and maintaining stability under high temperature conditions. Therefore, CeO2 is an ideal carrier for preparing Ru-based single-atom catalysts.

[0006] Although there have been literature reports on the Ru-based ammonia decomposition hydrogen production catalyst prepared by using the chemical interaction between CeO2 and Ru, the Ru component is distributed in the form of clusters, and the Ru loading is 0.3% - 1.0%. Theoretically, the Ru loading can be further reduced by improving the atomic utilization rate of Ru. Therefore, the preparation of Ru-based single-atom catalysts for catalytic ammonia decomposition hydrogen production reaction is an urgent problem to be solved at present, and it is of great significance in reducing the cost of Ru-based catalysts and realizing hydrogen energy utilization through ammonia decomposition hydrogen production. (Applied Catalysis B: Environmental, 2020, 268 118424, doi.org / 10.1016 / j.apcatb.2019.118424) Summary of the Invention

[0007] Aiming at the problems existing in the prior art, this application utilizes the chemical interaction between the oxide carrier and Ru to achieve the atomic dispersion of Ru on the surface of CeO2, effectively reducing the loading of metallic Ru in traditional Ru-based catalysts and improving the atomic utilization rate of noble metals. This Ru single-atom catalyst can be used in the process of ammonia decomposition hydrogen production, and catalyze the decomposition of ammonia (chemical formula: NH3) to produce nitrogen (chemical formula: N2) and hydrogen (chemical formula: H2) under high temperature conditions.

[0008] In one aspect of this application, a ruthenium-based catalyst is provided. The ruthenium-based catalyst includes a carrier and an active component supported on the carrier;

[0009] The carrier is cerium dioxide CeO2;

[0010] The active component is metallic ruthenium, and ruthenium atoms are uniformly dispersed in the form of single atoms on the surface of CeO2.

[0011] Optionally, in the ruthenium-based catalyst, the ruthenium loading is 0.01% - 0.3% of the mass of the ruthenium-based catalyst.

[0012] Another aspect of the present application provides a method for preparing the above-mentioned ruthenium-based catalyst. The preparation method of the ruthenium-based catalyst is an adsorption method. CeO2 is impregnated in a solution containing metal Ru, filtered, dried, and then heat-treated at a high temperature in a reducing atmosphere. By utilizing the chemical interaction between the oxide support and Ru, Ru is atomically dispersed on the surface of CeO2, effectively reducing the loading amount of metal Ru in the traditional Ru-based catalyst and improving the atomic utilization rate of the noble metal.

[0013] The preparation method includes:

[0014] Impregnating CeO2 in a ruthenium solution, drying, and performing a reduction treatment in a reducing atmosphere to obtain the ruthenium-based catalyst;

[0015] Wherein, the temperature of the reduction treatment is 150-450 °C, and the time of the reduction treatment is 0.5-5 h.

[0016] As a specific implementation manner, first, impregnate the cerium dioxide solid powder in a ruthenium solution with a certain concentration, perform suction filtration and drying treatments, and then heat and reduce it in a reducing gas to obtain the ruthenium-based single-atom catalyst material.

[0017] Optionally, the solute of the ruthenium solution is at least one of ruthenium trichloride (chemical formula: RuCl3), ruthenium nitrosyl nitrate (chemical formula: Ru(NO)(NO3)3), and ruthenium acetylacetonate (chemical formula: Ru(C5H7O2)3).

[0018] Optionally, the ruthenium solution further includes a solvent, and the solvent is water;

[0019] Optionally, in the ruthenium solution, the mass percentage of ruthenium is 0.005%-0.1%;

[0020] Optionally, the solid-liquid mass ratio of CeO2 to the ruthenium solution is selected from any value in 2:1-1:4 g / ml or the range value between any two of the above.

[0021] Optionally, the solid-liquid ratio of CeO2 to the ruthenium solution is independently selected from any value in 2 g / ml, 1.5 g / ml, 1 g / ml, 0.6 g / ml, 0.5 g / ml, 0.25 g / ml or the range value between any two of the above.

[0022] Optionally, the temperature of the reduction treatment is 200-400 °C, and the time of the reduction treatment is 1-3 h.

[0023] Optionally, the temperature of the reduction treatment is independently selected from any value in 150 °C, 200 °C, 250 °C, 300 °C, 350 °C, 400 °C, 450 °C or the range value between any two of the above.

[0024] Optionally, the time of the reduction treatment is independently selected from any value among 0.5 h, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h or the range value between any two of the above.

[0025] Optionally, the reducing atmosphere includes a reducing gas;

[0026] The reducing gas is ammonia and / or hydrogen;

[0027] Optionally, the reducing atmosphere further includes an inert gas, and the inert gas is selected from at least one of argon (chemical formula Ar) and helium (chemical formula He).

[0028] Optionally, in the reducing atmosphere, the volume fraction of ammonia in the reducing gas is 5% - 50%.

[0029] Optionally, the volume fraction of ammonia in the reducing gas is independently selected from any value among 5%, 10%, 20%, 30%, 40%, 50% or the range value between any two of the above.

[0030] Optionally, in the reducing atmosphere, the volume fraction of hydrogen in the reducing gas is 5% - 30%.

[0031] Optionally, the volume fraction of hydrogen in the reducing gas is independently selected from any value among 5%, 10%, 15%, 20%, 25%, 30% or the range value between any two of the above.

[0032] Optionally, the drying treatment means heating in an oven for a certain time;

[0033] Optionally, the drying temperature is 50 - 150 °C; the drying time is 3 - 24 h.

[0034] Optionally, the drying temperature is independently selected from any value among 50 °C, 60 °C, 70 °C, 80 °C, 90 °C, 100 °C, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C or the range value between any two of the above;

[0035] Optionally, the drying time is independently selected from any value among 3 h, 6 h, 9 h, 12 h, 15 h, 18 h, 21 h, 24 h or the range value between any two of the above.

[0036] Optionally, the drying temperature is 60 - 80 °C.

[0037] Another aspect of the present application provides an application of the above ruthenium-based catalyst in ammonia decomposition to produce hydrogen, characterized in that,

[0038] Contact the raw material gas containing ammonia with a catalyst and react to produce nitrogen and hydrogen;

[0039] Among them, the catalyst is the ruthenium-based catalyst described above.

[0040] Specifically, load the ruthenium-based single-atom catalyst material in a fixed-bed reactor, introduce the ammonia-containing gas, and at a certain reaction temperature, ammonia undergoes a chemical reaction in the reaction tube under the action of the catalyst to produce nitrogen and hydrogen.

[0041] Optionally, in the raw material gas, the volume fraction of ammonia is 0.5% to 100%.

[0042] Optionally, the temperature of the reaction is 300°C to 600°C.

[0043] Optionally, the temperature of the reaction is independently selected from any value of 300°C, 400°C, 500°C, 600°C or the range value between any two of the above.

[0044] Optionally, the space velocity of the raw material gas is 1000 to 30000 mL g Cat. -1 h -1 .

[0045] The beneficial effects that can be produced by this application include:

[0046] (1) The ruthenium-based catalyst provided by this application utilizes the chemical interaction between the oxide support and Ru to achieve the atomic dispersion of Ru on the surface of CeO2, effectively reducing the loading of metallic Ru in the traditional ruthenium-based catalyst and improving the atomic utilization rate of the noble metal. This Ru single-atom catalyst can be used in the process of ammonia decomposition to hydrogen, and catalyzes the decomposition of ammonia (chemical formula: NH3) to produce nitrogen (chemical formula: N2) and hydrogen (chemical formula: H2) under high-temperature conditions. The preparation method of this catalyst is simple, has high stability and low cost, and has broad application prospects in the field of hydrogen energy utilization such as ammonia decomposition hydrogenation stations.

[0047] (2) Compared with the traditional ruthenium-based catalyst, Ru in the ruthenium-based single-atom catalyst prepared by this application is dispersed in the form of single atoms, which improves the atomic utilization rate of Ru and reduces the cost of the ammonia decomposition to hydrogen catalyst, and has application prospects in fields such as ammonia decomposition hydrogenation stations. Description of the Drawings

[0048] Figure 1 It is the X-ray diffraction pattern of the Ru-based single-atom catalyst materials 1-4 in the examples of this application.

[0049] Figure 2 It is the high-resolution scanning transmission electron micrograph of the Ru-based single-atom catalyst material in Example 3 of this application, and the scale bar is 2 nm.

[0050] Figure 3 This is the high-resolution transmission electron microscopy image of the catalyst material in Comparative Example 1 of this application, and the scale bar is 1 nm.

[0051] Figure 4 This is the activity data of the Ru-based single-atom catalyst in Test Examples 1-3 of this application for ammonia decomposition to produce hydrogen. Detailed Description of the Invention

[0052] The present application will be described in detail below in conjunction with the embodiments, but the present application is not limited to these embodiments.

[0053] Unless otherwise specified, the raw materials in the embodiments of the present application are all purchased through commercial channels, among which:

[0054] Cerium dioxide was purchased from Sigma-Aldrich.

[0055] Ruthenium trichloride and ruthenium acetylacetonate were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0056] Ruthenium nitrosyl nitrate was purchased from Thermo Fisher Scientific Inc.

[0057] The X-ray diffraction pattern was measured by an Empyrean model X-ray diffractometer from Malvern Panalytical.

[0058] The high-resolution scanning transmission electron microscopy image was measured by a spherical aberration corrector electron microscope of the JEM-ARM200F model produced by JEOL Ltd.

[0059] The high-resolution transmission electron microscopy image was measured by an electron microscope of the 2100F model produced by JEOL Ltd.

[0060] The mass fraction of Ru in the catalyst material was measured by an ICP-OES spectrometer of the 7300DV model from PerkinElmer.

[0061] The conversion rate (C) in the embodiments of the present application was calculated from the product peak area obtained by a gas chromatograph of the GC7890 model from Agilent, and the hydrogen production rate (r) was the product of 1.5 times the reaction space velocity (GHSV) and the conversion rate, as shown in the following formula.

[0062]

[0063] r = 1.5 * GHSV * C

[0064] The preparation method of the Ru-based single-atom catalyst adopted in the present application includes the following steps:

[0065] First, impregnate the cerium dioxide solid powder in a ruthenium solution of a certain concentration. After suction filtration and drying, heat it in a reducing gas for reduction treatment to obtain the ruthenium-based single-atom catalyst material.

[0066] Example 1

[0067] Weigh 0.02 g of ruthenium nitrosyl nitrate (Ru(NO)(NO3)3), where the mass percentage of Ru is 31.3%. Add 3.0 g of water and stir to completely dissolve Ru(NO)(NO3)3. Then add 2.0 g of cerium dioxide (CeO2) powder and impregnate it in the dark for 4 h. After suction filtration and separation, place the solid powder in an oven at 60 °C and dry it for 12 h. Take out 0.1 g of the dried solid, load it on a fixed-bed reactor, and introduce a reducing gas (20% H2 - 80% He) with a gas flow rate of 50 mL / min. Heat it from 20 °C to 400 °C at a heating rate of 8 °C / min and hold it at this temperature for 1 h. Then stop heating and cool it to room temperature to obtain Ru-based single-atom catalyst material 1, where the ruthenium loading is 0.3% of the catalyst mass. As Figure 1 shown, the main X-ray diffraction peaks of Ru-based single-atom catalyst material 1 are located at diffraction peaks at 28.5, 33.1, 47.5, and 56.3°, corresponding to the (111), (200), (220), and (311) crystal planes of CeO2, respectively. The remaining diffraction peaks also match the standard card of CeO2, indicating that the dispersion of Ru in material 1 is very high and the grain size is lower than the detection limit of the X-ray diffractometer. In addition, from Figure 2 it can be seen that under the aberration-corrected electron microscope, no Ru particles can be observed, indicating that Ru is atomically dispersed on the surface of the carrier CeO2, and material 1 is a Ru-based single-atom catalyst.

[0068] Example 2

[0069] Weigh 0.01 g of Ru(NO)(NO3)3, where the mass percentage of Ru is 31.3%. Add 2.0 g of water and stir to completely dissolve Ru(NO)(NO3)3. Then add 3.0 g of CeO2 powder and impregnate it in the dark for 6 h. After suction filtration and separation, place the solid powder in an oven at 50 °C and dry it for 24 h. Take out 0.1 g of the dried solid, load it on a fixed-bed reactor, and introduce a reducing gas (5% H2 - 90% Ar) with a gas flow rate of 40 mL / min. Heat it from 20 °C to 300 °C at a heating rate of 8 °C / min and hold it at this temperature for 3 h. Then stop heating and cool it to room temperature to obtain Ru-based single-atom catalyst material 2, where the ruthenium loading is 0.1% of the catalyst mass.

[0070] Example 3

[0071] Weigh 1.6 g of ruthenium(III) chloride (RuCl3) solution, where the mass percentage of Ru is 0.07%, then add 1.4 g of water. After stirring, add 2.0 g of CeO2 powder, impregnate in the dark for 4 h, filter by suction to separate, and place the solid powder in an oven at 80 °C to dry for 8 h. Take out 0.1 g of the dried solid, load it on a fixed-bed reactor, introduce a reducing gas (10% NH3 - 90% He) with a gas flow rate of 50 mL / min, heat from 20 °C to 450 °C at a heating rate of 8 °C / min, and hold at this temperature for 0.5 h. Then stop heating and cool to room temperature to obtain Ru-based single-atom catalyst material 3, where the ruthenium loading is 0.5% of the catalyst mass.

[0072] Example 4

[0073] Weigh 0.9 g of Ru(NO)(NO3)3 solution, where the mass percentage of Ru is 0.05%, then add 2.1 g of water. After stirring, add 3.0 g of CeO2 powder, impregnate in the dark for 6 h, filter by suction to separate, and place the solid powder in an oven at 120 °C to dry for 6 h. Take out 0.1 g of the dried solid, load it on a fixed-bed reactor, introduce a reducing gas (30% H2 - 20% He - 50% Ar) with a gas flow rate of 25 mL / min, heat from 20 °C to 150 °C at a heating rate of 8 °C / min, and hold at this temperature for 1 h. Then stop heating and cool to room temperature to obtain Ru-based single-atom catalyst material 4, where the ruthenium loading is 0.01% of the catalyst mass.

[0074] Example 5

[0075] Weigh 1.0 g of ruthenium(III) chloride (RuCl3) solution, where the mass percentage of Ru is 0.005%, then add 1.0 g of water. After stirring, add 2.0 g of CeO2 powder, impregnate in the dark for 8 h, filter by suction to separate, and place the solid powder in an oven at 150 °C to dry for 2 h. Take out 0.1 g of the dried solid, load it on a fixed-bed reactor, introduce a reducing gas (50% NH3 - 50% He) with a gas flow rate of 20 mL / min, heat from 20 °C to 300 °C at a heating rate of 8 °C / min, and hold at this temperature for 2 h. Then stop heating and cool to room temperature to obtain Ru-based single-atom catalyst material 5.

[0076] Comparative Example 1

[0077] Weigh 1.0 g of ruthenium(III) chloride (RuCl3) solution, where the mass percentage of Ru is 0.08%, then add 1.0 g of water. After stirring, add 2.0 g of CeO2 powder, impregnate it in the dark for 4 h, filter it by suction for separation, and place the solid powder in an oven at 60 °C to dry for 8 h. Take out 0.1 g of the dried solid, pack it on a fixed-bed reactor, introduce a reducing gas (20% NH3 - 80% He) with a gas flow rate of 50 mL / min, heat it from 20 °C to 550 °C at a heating rate of 8 °C / min, and hold it at this temperature for 2 h. Then stop heating and cool it to room temperature to obtain the Ru-based catalyst as Material 6. As Figure 3 shown, after performing high-resolution transmission electron microscopy characterization on this material, Ru exists in the form of particles, and a Ru-based single-atom catalyst cannot be obtained.

[0078] Comparative Example 2

[0079] Weigh 0.02 g of Ru(NO)(NO3)3, add 3.0 g of water, stir to dissolve Ru(NO)(NO3)3, then add 2.0 g of CeO2 powder, impregnate it in the dark for 4 h, filter it by suction for separation, and place the solid powder in an oven at 80 °C to dry for 6 h. Take out 0.1 g of the dried solid, pack it on a fixed-bed reactor, introduce a reducing gas (50% H2 - 50% He) with a gas flow rate of 50 mL / min, heat it from 20 °C to 400 °C at a heating rate of 8 °C / min, and hold it at this temperature for 1 h. Then stop heating and cool it to room temperature to obtain the Ru-based catalyst as Material 7, where Ru is distributed on the surface of CeO2 in the form of particles, and a Ru-based single-atom catalyst cannot be obtained.

[0080] Test Example 1

[0081] Weigh 0.10 g of the Ru-based single-atom catalyst Material 1 and pack it in an atmospheric-pressure fixed-bed reactor. Introduce a raw material gas with a flow rate of 50 mL / min, and the composition of the raw material gas is 10% NH3 - 90% He. At a reaction temperature of 450 °C, the ammonia decomposition conversion rate on the Ru-based single-atom catalyst Material 1 is 16.5%. Calculated based on the mass fraction of Ru in the catalyst, the hydrogen production rate in the reaction is as Figure 4 shown, which is 1868 mmol g Ru -1 min -1 .

[0082] Test Example 2

[0083] Weigh 0.10 g of the Ru-based single-atom catalyst material 2 and load it into an atmospheric fixed-bed reactor. Feed the raw material gas at a flow rate of 50 mL / min. The composition of the raw material gas is 10% NH3 - 90% He. At a reaction temperature of 450 °C, the ammonia decomposition conversion rate on the Ru-based single-atom catalyst material 2 is 9.5%. Calculated based on the mass fraction of Ru in the catalyst, the hydrogen production rate in the reaction is as Figure 4 shown, which is 3366 mmol g Ru -1 min -1 .

[0084] Test Example 3

[0085] Weigh 0.10 g of the Ru-based single-atom catalyst material 3 and load it into an atmospheric fixed-bed reactor. Feed the raw material gas at a flow rate of 50 mL / min. The composition of the raw material gas is 10% NH3 - 90% He. At a reaction temperature of 450 °C, the ammonia decomposition conversion rate on the Ru-based single-atom catalyst material 2 is 7.4%. Calculated based on the mass fraction of Ru in the catalyst, the hydrogen production rate in the reaction is as Figure 4 shown, which is 5336 mmol g Ru -1 min -1 .

[0086] As described above, these are only several embodiments of the present application and do not impose any form of limitation on the present application. Although the present application is disclosed with preferred embodiments as above, it is not intended to limit the present application. Any person skilled in the relevant art can make some changes or modifications within the scope of the technical solution of the present application by using the disclosed technical content, which are equivalent to equivalent implementation cases and all fall within the scope of the technical solution.

Claims

1. A ruthenium-based catalyst, characterized in that, The ruthenium-based catalyst includes a support and an active component supported on the support; The support is CeO2; The active component is metallic ruthenium, and ruthenium atoms are dispersed in the form of single atoms on the surface of CeO2.

2. The ruthenium-based catalyst according to claim 1, characterized in that, In the ruthenium-based catalyst, the loading amount of ruthenium is 0.01% to 0.3% of the mass of the ruthenium-based catalyst.

3. A method for preparing the ruthenium-based catalyst according to any one of claims 1 to 2, characterized in that, The preparation method includes: Impregnating CeO2 in a ruthenium solution, drying, and performing a reduction treatment in a reducing atmosphere to obtain the ruthenium-based catalyst; Among them, the temperature of the reduction treatment is 150 to 450 °C, and the time of the reduction treatment is 0.5 to 5 h.

4. The preparation method according to claim 3, characterized in that, The solute in the ruthenium solution is at least one of ruthenium trichloride, ruthenium nitrosyl nitrate, and ruthenium acetylacetonate; The ruthenium solution further includes a solvent, and the solvent is water; In the ruthenium solution, the mass percentage of ruthenium is 0.005% to 0.1%; Preferably, the solid-liquid ratio of CeO2 to the ruthenium solution is 2:1 to 1:4 g / ml.

5. The preparation method according to claim 3, characterized in that, The temperature of the reduction treatment is 200 to 400 °C, and the time of the reduction treatment is 1 to 3 h.

6. The preparation method according to claim 3, characterized in that, The reducing atmosphere includes a reducing gas; The reducing gas is ammonia and / or hydrogen; Preferably, the reducing atmosphere further includes an inert gas, and the inert gas is selected from at least one of argon and helium.

7. The preparation method according to claim 6, characterized in that, In the reducing atmosphere, the volume fraction of ammonia in the reducing gas is 5% to 50%; Preferably, in the reducing atmosphere, the volume fraction of hydrogen in the reducing gas is 5% to 30%.

8. The preparation method according to claim 3, characterized in that, The temperature of the drying is 50 to 150 °C; The time of the drying is 3 to 24 h; Preferably, the temperature of the drying is 60 to 80 °C.

9. The application of the ruthenium-based catalyst according to any one of claims 1 to 2 in ammonia decomposition for hydrogen production, characterized in that, Contacting a raw material gas containing ammonia with the catalyst and reacting to generate nitrogen and hydrogen; Among them, the catalyst is the ruthenium-based catalyst according to any one of claims 1 to 2.

10. The application according to claim 9, characterized in that, In the raw material gas, the volume fraction of ammonia is 0.5% to 100%; The space velocity of the raw material gas is 1000 - 30000 mL g Cat. -1 h -1 ; The temperature of the reaction is 300 °C to 600 °C.

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