Ruthenium-based ammonia decomposition catalyst and preparation method and application thereof

Abstract

The invention discloses a ruthenium-based ammonia decomposition catalyst as well as a preparation method and application thereof. The ruthenium-based ammonia decomposition catalyst comprises a carrier, an active component and an auxiliary component, wherein the active component and the auxiliary component are loaded on the carrier; the active component is Ru; the auxiliary agent component is a metal oxide; the metal element in the metal oxide is selected from at least one of Li, K, Cs, Ca, Sr, Ba, Rb and Na; the carrier is selected from at least one of Al2O3, SiO2, CeO2, MgO and TiO2. Compared with the nickel-based catalyst used in the industry at present, the catalyst prepared by the method provided by the invention shows higher catalytic activity and stability in ammonia decomposition reaction, and the ammonia decomposition temperature can be reduced by 200-300 DEG C. When the gas production rate is the same, the loading amount of the catalyst and the equipment volume are greatly reduced, and the ammonia decomposition energy consumption is obviously reduced.

Description

Technical Field

[0001] The present application relates to a ruthenium-based ammonia decomposition catalyst, a preparation method and an application thereof, belonging to the technical field of catalyst preparation. Background Art

[0002] With the development of human society, the consumption of fossil energy (coal, oil, natural gas) has gradually increased, emitting a large amount of CO2 and causing a series of environmental problems such as global warming and ocean acidification. As a green and clean energy, hydrogen energy has the characteristics of high energy density (142 MJ kg-1) and zero emissions, and is the most ideal alternative energy to fossil fuels. Promoting the large-scale application of hydrogen energy is of great significance for building a clean, low-carbon, safe and efficient energy system.

[0003] Due to the characteristics of small molecular size and low density of hydrogen itself (the volume densities of gaseous and liquid states are 0.089 and 71 g / L respectively, and the corresponding temperatures are 25°C and -252°C), the storage and transportation of hydrogen face huge challenges. If the storage and transportation process of hydrogen can be avoided, the use cost of hydrogen will be greatly reduced, promoting the large-scale application of hydrogen energy. Ammonia as a hydrogen storage carrier has the following advantages: 1. Ammonia is easy to liquefy and store (the liquefaction pressure at 20°C is 0.8 MPa); 2. The high energy density (3000 Wh·kg -1 ) and high hydrogen-carrying capacity (17.6 wt%) of ammonia are much higher than those of methanol and other carbon-based compound fuels and compressed hydrogen; 3. The decomposition products of ammonia are N2 and H2, avoiding the poisoning of Pt electrodes by CO x substances. And the technology of synthesizing ammonia is very mature, and the price of ammonia is low. Therefore, ammonia as a hydrogen carrier converts the storage and transportation of hydrogen into the storage and transportation of ammonia, and ammonia decomposition to produce hydrogen has great application prospects.

[0004] The ammonia decomposition to produce hydrogen reaction is shown in Equation (1). This reaction is an endothermic reaction with an increase in volume. Therefore, increasing the temperature and decreasing the pressure are beneficial to the progress of the reaction. According to thermodynamic calculations, at normal pressure and a temperature of 400°C, the equilibrium conversion rate of ammonia decomposition can reach 99%. However, from a kinetic perspective, due to the very high activation energy of this reaction, the conversion rate of the ammonia decomposition reaction is extremely low under the condition of no catalyst catalysis at normal pressure. At normal pressure and without using any catalyst, the actual conversion rate of the ammonia decomposition reaction at 700°C is less than 10%. Therefore, a highly active catalyst is required to achieve efficient decomposition of ammonia.

[0005] 2NH3 = N2 + 3H2, ΔH = 92.5 kJ mol -1 (1)

[0006] Currently, the ammonia decomposition catalysts mainly include noble metal catalysts (such as Ru, Ir, etc.), non-noble metal catalysts (such as Fe, Co, Ni, Mo, etc.), transition metal carbides and nitrides (such as WC x , MoN x , etc.) and mixed catalysts of transition metals or their nitrides-alkali (earth) metal imide compounds (such as Co-Ba(NH2)2, MnN-Li2NH, etc.).

[0007] Currently, some applications for the preparation of ammonia decomposition catalysts have been patented. The following lists several reported patents for detailed description:

[0008] Chinese Patent CN112774676A has a publication name of: Ruthenium catalyst supported on rare earth oxide and its preparation method and use. This patent reports that a ruthenium catalyst supported on rare earth oxide is prepared by the deposition-precipitation method using rare earth oxide as the carrier and ruthenium as the active component for ammonia decomposition reaction. The catalyst involved in this patent is a rare earth oxide, which is difficult to produce on a large scale and has low catalytic efficiency.

[0009] Chinese Patent CN114570361A has a publication name of: A Ru-based catalyst for hydrogen production by ammonia decomposition and its preparation method. The catalyst reported in this patent uses carbon layer-modified SiO2 as the carrier of the ammonia decomposition catalyst, and the active component is metal ruthenium, which improves the surface basicity of the catalyst and is beneficial to improving the ammonia decomposition reaction efficiency. However, the carbon layer-modified SiO2 faces the problem of carbon layer instability during the actual reaction process, affecting the service life.

[0010] Chinese Patent CN115920942A has a publication name of: A Ru-based catalyst for hydrogen production by ammonia decomposition and its preparation and application methods. This patent reports the use of MOF74-coated ZIF 8 or ZIF67 as the carrier and ruthenium as the active component for ammonia decomposition reaction. However, MOF74, ZIF 8, and ZIF 67 are all difficult to prepare on a large scale and are still very far from practical applications.

[0011] Currently, there is an urgent need to develop an efficient ammonia decomposition catalyst that can meet the requirements of practical applications and can be produced on a large scale while improving the catalyst efficiency. Summary of the Invention

[0012] Aiming at the problems of complex preparation process and difficulty in large-scale production in the above-mentioned ammonia decomposition catalysts, a ruthenium-based ammonia decomposition catalyst, its preparation method and application are provided. By adopting an optimized preparation method and using a conventional carrier, a highly dispersed Ru-based catalyst is prepared, which can be produced on a large scale and has good performance in ammonia decomposition reaction.

[0013] According to one aspect of the present application, a ruthenium-based ammonia decomposition catalyst is provided. The ruthenium-based ammonia decomposition catalyst includes a carrier, and an active component and a promoter component supported on the carrier;

[0014] The active component is Ru;

[0015] The promoter component is a metal oxide;

[0016] The metal element in the metal oxide is selected from at least one of Li, K, Cs, Ca, Sr, Ba, Rb, and Na;

[0017] The carrier is selected from at least one of Al2O3, SiO2, CeO2, MgO, and TiO2.

[0018] Optionally, the active component accounts for 0.01 to 10 wt.% of the mass percentage of the ruthenium-based ammonia decomposition catalyst.

[0019] Optionally, the mass percentage of the active component in the ruthenium-based ammonia decomposition catalyst is independently selected from any value of 0.01 wt.%, 0.05 wt.%, 0.1 wt.%, 0.5 wt.%, 1 wt.%, 2 wt.%, 4 wt.%, 5 wt.%, 6 wt.%, 8 wt.%, 10 wt.% or a range value between any two of the above.

[0020] Optionally, the promoter component accounts for 1 to 10 wt.% of the mass percentage of the nickel-based ammonia decomposition catalyst.

[0021] Optionally, the mass percentage of the promoter component in the nickel-based ammonia decomposition catalyst is independently selected from any value of 1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, 5 wt.%, 6 wt.%, 7 wt.%, 8 wt.%, 10 wt.% or a range value between any two of the above.

[0022] Optionally, the carrier accounts for 80 to 98.99 wt.% of the mass percentage of the nickel-based ammonia decomposition catalyst.

[0023] Optionally, the mass percentage of the carrier in the nickel-based ammonia decomposition catalyst is independently selected from any value of 80 wt.%, 82 wt.%, 83 wt.%, 85 wt.%, 90 wt.%, 95 wt.%, 98 wt.%, 98.5 wt.%, 98.99 wt.% or a range value between any two of the above.

[0024] According to another aspect of the present application, a preparation method of the above-mentioned ruthenium-based ammonia decomposition catalyst is provided. The preparation method includes the following steps:

[0025] (1) In an inert atmosphere, a mixture I containing a ruthenium precursor salt and an alkali-containing ethylene glycol solution is subjected to Reaction I to obtain a Ru nano-sol;

[0026] (2) A mixture II containing the Ru nano-sol and a carrier-containing ethylene glycol solution is subjected to Reaction II, aging, and drying I to obtain a matrix containing the carrier;

[0027] (3) A mixture III containing the matrix with the carrier and a metal salt solution is impregnated, dried II, calcined, and reduced to obtain the ruthenium-based ammonia decomposition catalyst.

[0028] Optionally, in step (1), the ruthenium precursor salt is selected from at least one of ruthenium chloride, ruthenium nitrate, and ruthenium acetylacetonate.

[0029] Optionally, in step (1), the alkali in the alkali-containing ethylene glycol solution is selected from sodium hydroxide and / or potassium hydroxide.

[0030] Optionally, in step (1), the inert atmosphere is selected from nitrogen and / or argon.

[0031] Optionally, in step (1), the concentration of the alkali-containing ethylene glycol solution is 0.2 mol / L to 1 mol / L, and the concentration of the alkali-containing ethylene glycol solution is based on the molar concentration of the alkali.

[0032] Optionally, in step (1), the concentration of the alkali-containing ethylene glycol solution independently is selected from any value of 0.2 mol / L, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, 0.8 mol / L, 0.9 mol / L, 1 mol / L or the range value between any two of the above.

[0033] Optionally, in step (1), the concentration of the Ru nano-sol is 2 mg / mL to 20 mg / mL, and the concentration of the Ru nano-sol is based on the mass content of the Ru element.

[0034] Optionally, in step (1), the concentration of the Ru nano-sol independently is selected from any value of 2 mg / mL, 4 mg / mL, 6 mg / mL, 8 mg / mL, 10 mg / mL, 12 mg / mL, 14 mg / mL, 16 mg / mL, 20 mg / mL or the range value between any two of the above.

[0035] Optionally, in step (1), the temperature of Reaction I is 130 to 180 °C, and the time of Reaction I is 1 to 12 h.

[0036] Optionally, in step (2), the concentration of the carrier-containing ethylene glycol solution is 10 g / L to 50 g / L, and the concentration of the carrier-containing ethylene glycol solution is based on the mass concentration of the carrier.

[0037] Optionally, in step (2), the concentration of the ethylene glycol solution containing the carrier is independently selected from any value of 10 g / L, 15 g / L, 20 g / L, 25 g / L, 30 g / L, 35 g / L, 40 g / L, 45 g / L, 50 g / L or the range value between any two of the above.

[0038] Optionally, in step (2), the temperature of Reaction II is 60 - 80 °C, and the time of Reaction II is 1 - 4 h.

[0039] Optionally, in step (2), the aging time is 1 - 4 h.

[0040] Optionally, in step (2), the temperature of Drying I is 60 - 120 °C, and the time of Drying I is 4 - 12 h.

[0041] Optionally, in step (3), the metal salt solution is selected from at least one of nitrates and chlorides containing metal elements.

[0042] Optionally, the metal element is selected from at least one of Li, K, Cs, Ca, Sr, Ba, Rb, Na.

[0043] Optionally, the metal element is selected from at least one of Na, K, Cs, Ca, Ba.

[0044] Optionally, the mass concentration of the metal salt solution is 0.1 wt% - 10 wt%, and the mass concentration of the metal salt solution is calculated based on the mass content of the metal element.

[0045] Optionally, the mass concentration of the metal salt solution is independently selected from any value of 0.1 wt%, 0.5 wt.%, 1 wt.%, 2 wt.%, 4 wt.%, 5 wt.%, 6 wt.%, 8 wt.%, 10 wt.% or the range value between any two of the above.

[0046] Optionally, in step (3), the impregnation time is 0.5 - 48 h.

[0047] Optionally, in step (3), the temperature of Drying II is 60 - 120 °C, and the time of Drying II is 4 - 12 h.

[0048] Optionally, the calcination temperature is 200 - 400 °C, and the calcination time is 4 - 12 h.

[0049] Preferably, the reduction is a high-temperature gas-phase reduction method, and the reducing atmosphere for the reduction is selected from ammonia gas and / or hydrogen gas;

[0050] Optionally, the volume hourly space velocity of the reducing atmosphere for reduction is 100 to 3600 h -1 .

[0051] Optionally, the heating rate during reduction is 1 to 10 °C / min, the reduction temperature is 200 to 600 °C, and the reduction time is 1 to 48 h.

[0052] Optionally, the reduction is a high-temperature gas-phase reduction method. The reducing atmosphere for reduction is selected from one of ammonia gas, hydrogen gas, and ammonia-hydrogen mixed gas. The volume hourly space velocity of the reducing gas is 100 to 3600 h -1 , the heating rate from room temperature to the reduction temperature is 1 to 10 °C / min, the reduction temperature is 200 to 600 °C, the pressure is atmospheric pressure, and the reduction time is 1 to 48 h.

[0053] According to another aspect of the present application, there is provided an application of the ruthenium-based ammonia decomposition catalyst described above in ammonia decomposition.

[0054] Optionally, the reaction space velocity of the ammonia decomposition is 200 to 60000 ml / g·h.

[0055] Optionally, the reaction temperature of the ammonia decomposition is 300 to 900 °C.

[0056] Optionally, the reaction temperature of the ammonia decomposition is 350 to 500 °C.

[0057] As an optional implementation manner, the present application is realized through the following technical solutions:

[0058] The ruthenium-based ammonia decomposition catalyst includes the following steps:

[0059] a: Preparation of Ru nano-sol. A solution containing a Ru precursor salt is prepared, and then an ethylene glycol solution of a base with a certain concentration is added. After mixing evenly, it is transferred to an oil bath and stirred for a period of time under the protection of argon or nitrogen to obtain Ru nano-sol.

[0060] b: Preparation of Ru / S. Weigh a certain amount of Ru nano-sol and drop it into a stirred ethylene glycol suspension of an S oxide support, stir and react in a water bath for a period of time, then age, filter and wash while it is hot, and obtain a Ru / S sample after drying;

[0061] c: Preparation of Ru-X / S catalyst. The Ru / S sample prepared in step b is impregnated in a salt solution of an alkali metal or alkaline earth metal, dried, calcined, and reduced I to obtain the Ru-X / S catalyst.

[0062] Optionally, the oxide support S in step b is at least one of Al2O3, MgO, and CeO2.

[0063] The present application discloses a low-temperature and highly efficient ammonia decomposition catalyst, a preparation method thereof, and an application thereof. The catalyst comprises a carrier, an auxiliary agent, and an active component. The carrier is alumina, magnesia, cerium oxide, silica, or titanium oxide; the auxiliary agent is an alkali metal and / or an alkaline earth metal; and the active component is ruthenium. Preparation method: First, synthesize a Ru sol, and then load the Ru sol and the auxiliary agent onto the carrier. Finally, treat the obtained Ru-X / S supported catalytic material under a reducing atmosphere. The catalyst prepared according to the method provided by the present invention exhibits higher catalytic activity and stability in the ammonia decomposition reaction compared with the nickel-based catalyst currently used in industry, and the ammonia decomposition temperature can be reduced by 200 °C to 300 °C. When the gas production is the same, the loading amount of the catalyst and the volume of the equipment are greatly reduced, and the energy consumption for ammonia decomposition is significantly reduced.

[0064] The beneficial effects that can be produced by the present application include:

[0065] 1) The ammonia decomposition catalyst provided by the present application can achieve efficient decomposition of ammonia at a lower temperature.

[0066] 2) For the ammonia decomposition catalyst provided by the present application, the carriers used are all commonly used carriers in industry, which are cheap and easily available, and large-scale production can be realized.

[0067] 3) The ruthenium-based ammonia decomposition catalyst, a preparation method thereof, and an application thereof provided by the present application have the advantages of low ammonia decomposition reaction temperature, high ammonia space velocity, and high ammonia conversion rate. The catalyst prepared according to the method provided by the present invention exhibits higher catalytic activity and stability in the ammonia decomposition reaction compared with the nickel-based catalyst currently used in industry, and the ammonia decomposition temperature can be reduced by 200 °C to 300 °C. When the gas production is the same, the loading amount of the catalyst and the volume of the equipment are greatly reduced, and the energy consumption for ammonia decomposition is significantly reduced. Specific Embodiments

[0068] The present application will be described in detail below in conjunction with embodiments, but the present application is not limited to these embodiments.

[0069] Unless otherwise specified, the raw materials in the embodiments of the present application are all purchased through commercial channels.

[0070] The products of ammonia decomposition are detected by an Agilent 7890B gas chromatograph, using a Propark Q chromatographic column and a TCD detector.

[0071]

[0072] The peak area of N2 in the reaction tail gas detected by the TCD detector;

[0073] The peak area of NH3 in the reaction tail gas detected by the TCD detector;

[0074] Molar correction factor of NH3 relative to N2, TCD detector.

[0075] Example 1

[0076] 1) Prepare Ru nanosol.

[0077] Dissolve 20 g of RuCl3 in 80 g of 10 wt% hydrochloric acid aqueous solution to obtain Ru solution A with a Ru mass content of 10 wt%. Weigh 1 g of 10 wt% Ru solution A, add 50 mL of sodium hydroxide ethylene glycol solution with a molar concentration of 0.25 mol L -1 Stir at room temperature for 1 h, then transfer it to an oil bath at 160 °C and stir and react for 1 h under argon atmosphere protection to obtain Ru sol (Ru mass concentration is 2 mg mL -1 ).

[0078] 2) Prepare Ru / S sample.

[0079] Weigh 1.0 g of Al2O3 support and add it to a beaker containing 100 mL of ethylene glycol. Stir in a water bath at 80 °C for 20 min to form an Al2O3 ethylene glycol suspension. Measure 5 ml of Ru sol with a Ru mass concentration of 2 mg mL -1 Drop it into the vigorously stirred Al2O3 support suspension, react at 80 °C for 3 h, age for 1 h, filter and wash while it is hot, and then dry in an oven at 80 °C for 6 h to obtain Ru / Al2O3 sample, denoted as 1% Ru / Al2O3.

[0080] 3) Prepare Ru-X / S catalyst.

[0081] Weigh 1.0 g of the prepared 1% Ru / Al2O3 support, weigh 0.0259 g of KNO3, dissolve it in 2 g of deionized water to form a mixed solution with a K mass concentration of 0.49 wt%, drop it into the 1% Ru / Al2O3 sample and mix it evenly. Impregnate at room temperature for 12 h, dry at 80 °C for 12 h, calcine in air atmosphere at 300 °C for 4 h, with a K mass content of 1%. Then, carry out hydrogen reduction, the temperature is 300 °C, the heating rate from room temperature to the reduction temperature is 5 °C / min, the volume space velocity of hydrogen is 100 h -1 , the pressure is atmospheric pressure, and the reduction time is 4 h. Obtain the catalyst, denoted as 1% Ru-1% K / Al2O3.

[0082] Reaction conditions for ammonia decomposition of the catalyst: ammonia concentration is 99.9%, fixed-bed reactor, reaction temperature is 400 °C - 500 °C, and space velocity is 30000 ml / g·h. The reaction results are shown in Table 1.

[0083] Example 2

[0084] Weigh 1.0 g of the 1% Ru / Al₂O₃ support prepared in Example 1. Weigh 0.0778 g of KNO₃, dissolve it in 2 g of deionized water to form a mixed solution with a mass concentration of K of 1.44 wt%, and drop it into the 1% Ru / Al₂O₃ sample and mix them evenly. Impregnate at room temperature for 2 h, dry at 60 °C for 12 h, and calcine in an air atmosphere at 200 °C for 12 h, with the mass content of K being 3%. Then, carry out ammonia reduction on it, with the temperature being 600 °C, the heating rate from room temperature to the reduction temperature being 10 °C / min, the volumetric space velocity of hydrogen being 3600 h -1 , under atmospheric pressure, and the reduction time being 12 h. A catalyst is obtained, denoted as 1% Ru-3% K / Al₂O₃.

[0085] Reaction conditions for the catalyst to decompose ammonia: ammonia concentration is 99.9%, fixed-bed reactor, reaction temperature is 400 °C - 500 °C, and space velocities are 200, 1000, 30000, and 60000 ml / g·h respectively. The reaction results are shown in Table 1.

[0086] Example 3

[0087] Weigh 1.0 g of the 1% Ru / Al₂O₃ support prepared in Example 1. Weigh 0.1296 g of KNO₃, dissolve it in 2 g of deionized water to form a mixed solution with a mass concentration of K of 2.35 wt%, and drop it into the 1% Ru / Al₂O₃ sample and mix them evenly. Impregnate at room temperature for 48 h, dry at 120 °C for 4 h, and calcine in an air atmosphere at 400 °C for 4 h, with the mass content of K being 5%. Then, carry out reduction with a hydrogen-ammonia mixed gas, with the hydrogen ratio being 50%, the temperature being 300 °C, the heating rate from room temperature to the reduction temperature being 10 °C / min, and the volumetric space velocity of hydrogen being 2000 h -1 , under atmospheric pressure, and the reduction time being 4 h. A catalyst is obtained, denoted as 1% Ru-5% K / Al₂O₃.

[0088] Reaction conditions for the catalyst to decompose ammonia: ammonia concentration is 99.9%, fixed-bed reactor, reaction temperature is 400 °C - 500 °C, and the space velocity is 30000 ml / g·h. The reaction results are shown in Table 1.

[0089] Example 4

[0090] Weigh 1.0 g of the 1% Ru / Al₂O₃ support prepared in Example 1. Weigh 0.2074 g of KNO₃, dissolve it in 2 g of deionized water to form a mixed solution with a K mass concentration of 3.62 wt%, and add it dropwise to the 1% Ru / Al₂O₃ sample and mix them evenly. Immerse at room temperature for 12 h, dry at 100 °C for 6 h, and calcine in an air atmosphere at 300 °C for 6 h, with a K mass content of 8%. Then, perform hydrogen reduction on it at a temperature of 300 °C, with a heating rate from room temperature to the reduction temperature of 5 °C / min, a hydrogen volumetric space velocity of 2000 h -1 , at atmospheric pressure, and a reduction time of 4 h. The catalyst obtained is denoted as 1% Ru-8% K / Al₂O₃.

[0091] Reaction conditions for ammonia decomposition over the catalyst: ammonia concentration is 99.9%, fixed-bed reactor, reaction temperature is 400 °C to 500 °C, and space velocity is 30000 ml / g·h. The reaction results are shown in Table 1.

[0092] Example 5

[0093] Weigh 1.0 g of the 1% Ru / Al₂O₃ support prepared in Example 1. Weigh 0.2592 g of KNO₃, dissolve it in 2 g of deionized water to form a mixed solution with a K mass concentration of 4.43 wt%, and add it dropwise to the 1% Ru / Al₂O₃ sample and mix them evenly. Immerse at room temperature for 12 h, dry at 120 °C for 6 h, and calcine in an air atmosphere at 300 °C for 6 h, with a K mass content of 10%. Then, perform hydrogen reduction on it at a temperature of 300 °C, with a heating rate from room temperature to the reduction temperature of 5 °C / min, a hydrogen volumetric space velocity of 2000 h -1 , at atmospheric pressure, and a reduction time of 4 h. The catalyst obtained is denoted as 1% Ru-10% K / Al₂O₃.

[0094] Reaction conditions for ammonia decomposition over the catalyst: ammonia concentration is 99.9%, fixed-bed reactor, reaction temperature is 400 °C to 500 °C, and space velocity is 30000 ml / g·h. The reaction results are shown in Table 1.

[0095] Example 6

[0096] Weigh 1.0 g of the Al₂O₃ support and add it to a beaker containing 100 mL of ethylene glycol. Stir in a water bath at 80 °C for 20 min to form an Al₂O₃ ethylene glycol suspension. Measure 0.05 ml of the Ru sol with a Ru mass concentration of 2 mg mL -1 prepared in Example 1 and add it dropwise to the vigorously stirred Al₂O₃ support suspension. React at 80 °C for 3 h, age for 1 h, filter and wash while it is hot, and then dry in an oven at 80 °C for 6 h to obtain the Ru / Al₂O₃ sample, denoted as 0.01% Ru / Al₂O₃.

[0097] Weigh 1.0 g of the prepared 0.01% Ru / Al₂O₃ support. Weigh 0.0778 g of KNO₃, dissolve it in 2 g of deionized water to form a mixed solution with a K mass concentration of 1.44 wt%. Drop it into the 0.01% Ru / Al₂O₃ sample and mix them evenly. Impregnate at room temperature for 12 h, dry at 80 °C for 12 h, and calcine in air atmosphere at 300 °C for 4 h, with the K mass content being 3%. Then, carry out hydrogen reduction at a temperature of 300 °C, with a heating rate from room temperature to the reduction temperature of 5 °C / min and a hydrogen volumetric space velocity of 1000 h -1 , at atmospheric pressure and a reduction time of 4 h. The catalyst obtained is denoted as 0.01% Ru-3% K / Al₂O₃.

[0098] Reaction conditions for ammonia decomposition by the catalyst: ammonia concentration is 99.9%, fixed-bed reactor, reaction temperature is 400 °C to 500 °C, and space velocity is 30000 ml / g·h. The reaction results are shown in Table 1.

[0099] Example 7

[0100] 1) Prepare Ru nano-sol.

[0101] Dissolve 10 g of ruthenium nitrate in 20 g of deionized water to obtain Ru solution B with a Ru mass content of 10 wt%. Weigh 5 g of 10 wt% Ru solution B, add 50 mL of potassium hydroxide ethylene glycol solution with a molar concentration of 0.5 mol L -1 , stir at room temperature for 1 h, then transfer it to an oil bath at 180 °C, and stir and react for 12 h under argon atmosphere protection to obtain Ru sol (Ru mass concentration is 10 mg mL -1 ).

[0102] 2) Prepare Ru / S sample.

[0103] Weigh 2.0 g of Al₂O₃ support and add it to a beaker containing 100 mL of ethylene glycol, stir in a water bath at 80 °C for 20 min to form an Al₂O₃ ethylene glycol suspension. Measure 20 ml of Ru sol with a Ru mass concentration of 10 mg mL -1 and drop it into the vigorously stirred Al₂O₃ support suspension, react at 80 °C for 4 h, age for 4 h, filter and wash while it is hot, and then put it in an oven at 120 °C to dry for 4 h to obtain the Ru / Al₂O₃ sample, denoted as 10% Ru / Al₂O₃.

[0104] 3) Prepare Ru-X / S catalyst.

[0105] Weigh 1.0 g of the prepared 10% Ru / Al₂O₃ support. Weigh 0.0778 g of KNO₃, dissolve it in 2 g of deionized water to form a mixed solution with a mass concentration of K being 1.44 wt%, and drop it into the 10% Ru / Al₂O₃ sample and mix them evenly. Impregnate at room temperature for 12 h, dry at 80 °C for 12 h, and calcine in air atmosphere at 300 °C for 4 h, with the mass content of K being 3%. Then, carry out hydrogen reduction on it at a temperature of 600 °C, with a heating rate from room temperature to the reduction temperature of 5 °C / min and a hydrogen volume space velocity of 3600 h -1 , at atmospheric pressure, and the reduction time is 1 h. The obtained catalyst is denoted as 10% Ru-3% K / Al₂O₃.

[0106] The reaction conditions for the catalyst in ammonia decomposition: the ammonia concentration is 99.9%, in a fixed-bed reactor, the reaction temperature is 400 °C to 500 °C, and the space velocity is 30000 ml / g·h. The reaction results are shown in Table 1.

[0107] Example 8

[0108] Weigh 1.0 g of the 1% Ru / Al₂O₃ support prepared in Example 1. Weigh 0.4967 g of LiNO₃, dissolve it in 2 g of deionized water to form a mixed solution with a mass concentration of Li being 2.0 wt%, and drop it into the 1% Ru / Al₂O₃ sample and mix them evenly. Impregnate at room temperature for 12 h, dry at 120 °C for 6 h, and calcine in air atmosphere at 300 °C for 6 h, with the mass content of Li being 5%. Then, carry out hydrogen reduction on it at a temperature of 300 °C, with a heating rate from room temperature to the reduction temperature of 5 °C / min and a hydrogen volume space velocity of 1000 h -1 , at atmospheric pressure, and the reduction time is 4 h. The obtained catalyst is denoted as 1% Ru-5% Li / Al₂O₃.

[0109] The reaction conditions for the catalyst in ammonia decomposition: the ammonia concentration is 99.9%, in a fixed-bed reactor, the reaction temperature is 400 °C to 500 °C, and the space velocity is 30000 ml / g·h. The reaction results are shown in Table 1.

[0110] Example 9

[0111] Weigh 1.0 g of the 1% Ru / Al₂O₃ support prepared in Example 1. Weigh 0.1270 g of NaCl, dissolve it in 2 g of deionized water to form a mixed solution with a mass concentration of Na being 2.35 wt%, and drop it into the 1% Ru / Al₂O₃ sample and mix them evenly. Impregnate at room temperature for 12 h, dry at 120 °C for 6 h, and calcine in air atmosphere at 300 °C for 6 h, with the mass content of Na being 5%. Then, carry out hydrogen reduction on it at a temperature of 300 °C, with a heating rate from room temperature to the reduction temperature of 5 °C / min and a hydrogen volume space velocity of 1000 h-1 , the pressure is atmospheric pressure, and the reduction time is 4 h. A catalyst is obtained and denoted as 1% Ru-5% Na / Al2O3.

[0112] Reaction conditions for the catalyst in ammonia decomposition: ammonia concentration is 99.9%, fixed-bed reactor, reaction temperature is 400 °C to 500 °C, and space velocity is 30,000 ml / g·h. The reaction results are shown in Table 1.

[0113] Example 10

[0114] Weigh 1.0 g of the 1% Ru / Al2O3 support prepared in Example 1. Weigh 0.0863 g of RbNO3, dissolve it in 2 g of deionized water to form a mixed solution with a mass concentration of Rb of 2.4 wt%. Drop it onto the 1% Ru / Al2O3 sample and mix evenly. Impregnate at room temperature for 12 h, dry at 120 °C for 6 h, and calcine in air atmosphere at 300 °C for 6 h, with the mass content of Rb being 5%. Then, carry out hydrogen reduction at a temperature of 300 °C, with a heating rate from room temperature to the reduction temperature of 5 °C / min and a hydrogen volume space velocity of 1000 h -1 , the pressure is atmospheric pressure, and the reduction time is 4 h. A catalyst is obtained and denoted as 1% Ru-5% Rb / Al2O3.

[0115] Reaction conditions for the catalyst in ammonia decomposition: ammonia concentration is 99.9%, fixed-bed reactor, reaction temperature is 400 °C to 500 °C, and space velocity is 30,000 ml / g·h. The reaction results are shown in Table 1.

[0116] Example 11

[0117] Weigh 1.0 g of the 1% Ru / Al2O3 support prepared in Example 1. Weigh 0.0733 g of CsNO, dissolve it in 2 g of deionized water to form a mixed solution with a mass concentration of Cs of 2.41 wt%. Drop it onto the 1% Ru / Al2O3 sample and mix evenly. Impregnate at room temperature for 12 h, dry at 120 °C for 6 h, and calcine in air atmosphere at 300 °C for 6 h, with the mass content of Cs being 5%. Then, carry out hydrogen reduction at a temperature of 300 °C, with a heating rate from room temperature to the reduction temperature of 5 °C / min and a hydrogen volume space velocity of 1000 h -1 , the pressure is atmospheric pressure, and the reduction time is 4 h. A catalyst is obtained and denoted as 1% Ru-5% Cs / Al2O3.

[0118] Reaction conditions for the catalyst in ammonia decomposition: ammonia concentration is 99.9%, fixed-bed reactor, reaction temperature is 400 °C to 500 °C, and space velocity is 30,000 ml / g·h. The reaction results are shown in Table 1.

[0119] Example 12

[0120] Weigh 1.0 g of the 1% Ru / Al₂O₃ support prepared in Example 1. Weigh 0.2047 g of Ca(NO₃)₂, dissolve it in 2 g of deionized water to form a mixed solution with a mass concentration of Ca of 2.27 wt%, and drop it into the 1% Ru / Al₂O₃ sample and mix them evenly. Impregnate at room temperature for 12 h, dry at 120 °C for 6 h, and calcine in an air atmosphere at 300 °C for 6 h, with a Ca mass content of 5%. Then, perform hydrogen reduction on it at a temperature of 300 °C, with a heating rate from room temperature to the reduction temperature of 5 °C / min, a hydrogen volumetric space velocity of 1000 h -1 , at atmospheric pressure, and a reduction time of 4 h. A catalyst is obtained, denoted as 1% Ru - 5% Ca / Al₂O₃.

[0121] Reaction conditions for the catalyst in ammonia decomposition: ammonia concentration is 99.9%, fixed-bed reactor, reaction temperature is 400 °C to 500 °C, and space velocity is 30000 ml / g·h. The reaction results are shown in Table 1.

[0122] Example 13

[0123] Weigh 1.0 g of the 1% Ru / Al₂O₃ support prepared in Example 1. Weigh 0.1208 g of Sr(NO₃)₂, dissolve it in 2 g of deionized water to form a mixed solution with a mass concentration of Sr of 2.36 wt%, and drop it into the 1% Ru / Al₂O₃ sample and mix them evenly. Impregnate at room temperature for 12 h, dry at 120 °C for 6 h, and calcine in an air atmosphere at 300 °C for 6 h, with an Sr mass content of 5%. Then, perform hydrogen reduction on it at a temperature of 300 °C, with a heating rate from room temperature to the reduction temperature of 5 °C / min, a hydrogen volumetric space velocity of 1000 h -1 , at atmospheric pressure, and a reduction time of 4 h. A catalyst is obtained, denoted as 1% Ru - 5% Sr / Al₂O₃.

[0124] Reaction conditions for the catalyst in ammonia decomposition: ammonia concentration is 99.9%, fixed-bed reactor, reaction temperature is 400 °C to 500 °C, and space velocity is 30000 ml / g·h. The reaction results are shown in Table 1.

[0125] Example 14

[0126] Weigh 1.0 g of the 1% Ru / Al2O3 support prepared in Example 1. Weigh 0.0952 g of Ba(NO3)2 and dissolve it in 2 g of deionized water to form a mixed solution with a Ba mass concentration of 2.36 wt%. Drop it into the 1% Ru / Al2O3 sample and mix them evenly. Impregnate at room temperature for 12 h, dry at 120 °C for 6 h, and calcine in air atmosphere at 300 °C for 6 h, with the Ba mass content being 5%. Then, perform hydrogen reduction on it at a temperature of 300 °C, with a heating rate from room temperature to the reduction temperature of 5 °C / min, a hydrogen volumetric space velocity of 1000 h -1 , at atmospheric pressure, and a reduction time of 4 h. A catalyst is obtained, denoted as 1% Ru-5% Ba / Al2O3.

[0127] Reaction conditions for the catalyst in ammonia decomposition: ammonia concentration is 99.9%, in a fixed-bed reactor, reaction temperature is 400 °C to 500 °C, and space velocity is 30000 ml / g·h. The reaction results are shown in Table 1.

[0128] Example 15

[0129] 1) Prepare Ru nano-sol.

[0130] Dissolve 14 g of ruthenium acetylacetonate in 20 g of ethylene glycol to obtain Ru solution C with a Ru mass content of 10 wt%. Weigh 10 g of 10 wt% Ru solution C, add 50 mL of potassium hydroxide ethylene glycol solution with a molar concentration of 1.0 mol L -1 , stir at room temperature for 1 h, then transfer it to an oil bath at 130 °C, and stir and react for 1 h under argon atmosphere protection to obtain Ru sol (Ru mass concentration is 20 mg mL -1 ).

[0131] 2) Prepare Ru / S sample.

[0132] Weigh 5.0 g of MgO support and add it to a beaker containing 100 mL of ethylene glycol, stir in a water bath at 80 °C for 20 min to form a MgO ethylene glycol suspension. Measure 2.5 ml of Ru sol with a Ru mass concentration of 20 mg mL -1 and drop it into the vigorously stirred MgO support suspension. React at 80 °C for 4 h, age for 4 h, filter and wash while it is hot, and then put it in an oven at 120 °C to dry for 4 h to obtain the Ru / MgO sample, denoted as 1% Ru / MgO.

[0133] 3) Prepare Ru-X / S catalyst.

[0134] Weigh 1.0 g of the prepared 1% Ru / MgO support. Weigh 0.0778 g of KNO₃, dissolve it in 20 g of deionized water to form a mixed solution with a K mass concentration of 0.2 wt%, add it dropwise to the 1% Ru / MgO sample and mix them evenly. Impregnate at room temperature for 12 h, dry at 80 °C for 12 h, and calcine in air atmosphere at 300 °C for 4 h, with the K mass content being 3%. Then, conduct hydrogen reduction on it at a temperature of 600 °C, with a heating rate from room temperature to the reduction temperature of 5 °C / min, a hydrogen volumetric space velocity of 2000 h -1 , at atmospheric pressure, and a reduction time of 1 h. Obtain the catalyst, denoted as 1% Ru-3% K / MgO.

[0135] The reaction conditions for ammonia decomposition using the catalyst are: ammonia concentration of 99.9%, fixed-bed reactor, reaction temperature of 400 °C to 500 °C, and space velocity of 30000 ml / g·h. The reaction results are shown in Table 1.

[0136] Example 16

[0137] Weigh 5.0 g of the CeO₂ support and add it to a beaker containing 100 mL of ethylene glycol. Stir in a water bath at 80 °C for 20 min to form a CeO₂ ethylene glycol suspension. Measure 2.5 ml of Ru sol with a Ru mass concentration of 20 mg / mL -1 and add it dropwise to the vigorously stirred CeO₂ support suspension. React at 80 °C for 4 h, age for 4 h, filter and wash while it is hot, and then place it in an oven at 120 °C to dry for 4 h to obtain the Ru / CeO₂ sample, denoted as 1% Ru / CeO₂.

[0138] Weigh 1.0 g of the prepared 1% Ru / CeO₂ support. Weigh 0.0778 g of KNO₃, dissolve it in 20 g of deionized water to form a mixed solution with a K mass concentration of 0.2 wt%, add it dropwise to the 1% Ru / CeO₂ sample and mix them evenly. Impregnate at room temperature for 12 h, dry at 80 °C for 12 h, and calcine in air atmosphere at 300 °C for 4 h, with the K mass content being 3%. Then, conduct hydrogen reduction on it at a temperature of 600 °C, with a heating rate from room temperature to the reduction temperature of 5 °C / min, a hydrogen volumetric space velocity of 2000 h -1 , at atmospheric pressure, and a reduction time of 1 h. Obtain the catalyst, denoted as 1% Ru-3% K / CeO₂.

[0139] The reaction conditions for ammonia decomposition using the catalyst are: ammonia concentration of 99.9%, fixed-bed reactor, reaction temperature of 400 °C to 500 °C, and space velocity of 30000 ml / g·h. The reaction results are shown in Table 1.

[0140] Example 17

[0141] Weigh 5.0 g of the SiO2 support and add it to a beaker containing 100 mL of ethylene glycol. Stir for 20 min in a water bath at 80 °C to form a SiO2 ethylene glycol suspension. Measure 2.5 ml of Ru sol with a Ru mass concentration of 20 mg / mL -1 and add it dropwise to the vigorously stirred SiO 22 support suspension. React at 80 °C for 4 h, age for 4 h, filter and wash while it is hot, and then dry in an oven at 120 °C for 4 h to obtain the Ru / SiO2 sample, denoted as 1% Ru / SiO2.

[0142] Weigh 1.0 g of the prepared 1% Ru / SiO2 support, weigh 0.0778 g of KNO3, dissolve it in 20 g of deionized water to form a mixed solution with a K mass concentration of 0.2 wt%, add it dropwise to the 1% Ru / SiO2 sample and mix evenly. Impregnate at room temperature for 12 h, dry at 80 °C for 12 h, and calcine in an air atmosphere at 300 °C for 4 h, with a K mass content of 3%. Then, carry out hydrogen reduction at a temperature of 600 °C, with a heating rate from room temperature to the reduction temperature of 5 °C / min and a hydrogen volumetric space velocity of 2000 h -1 , at atmospheric pressure, and a reduction time of 1 h. Obtain the catalyst, denoted as 1% Ru-3% K / SiO2.

[0143] Reaction conditions for the catalyst in ammonia decomposition: ammonia concentration is 99.9%, fixed-bed reactor, reaction temperature is 400 °C - 500 °C, and space velocity is 30000 ml / g·h. The reaction results are shown in Table 1.

[0144] Example 18

[0145] Weigh 5.0 g of the TiO2 support and add it to a beaker containing 100 mL of ethylene glycol. Stir for 20 min in a water bath at 80 °C to form a TiO2 ethylene glycol suspension. Measure 2.5 ml of Ru sol with a Ru mass concentration of 20 mg / mL -1 and add it dropwise to the vigorously stirred TiO 22 support suspension. React at 80 °C for 4 h, age for 4 h, filter and wash while it is hot, and then dry in an oven at 120 °C for 4 h to obtain the Ru / TiO2 sample, denoted as 1% Ru / TiO2.

[0146] Weigh 1.0 g of the prepared 1% Ru / TiO₂ support. Weigh 0.0778 g of KNO₃, dissolve it in 20 g of deionized water to form a mixed solution with a K mass concentration of 0.2 wt%, and add it dropwise to the 1% Ru / TiO₂ sample and mix them evenly. Impregnate at room temperature for 12 h, dry at 80 °C for 12 h, and calcine in air atmosphere at 300 °C for 4 h, with a K mass content of 3%. Then, perform hydrogen reduction on it at a temperature of 600 °C, with a heating rate from room temperature to the reduction temperature of 5 °C / min, a hydrogen volume space velocity of 2000 h -1 , and a pressure of atmospheric pressure, and a reduction time of 1 h. The catalyst obtained is denoted as 1% Ru-3% K / TiO₂.

[0147] The reaction conditions for ammonia decomposition using the catalyst are as follows: ammonia concentration is 99.9%, in a fixed-bed reactor, the reaction temperature is 400 °C to 500 °C, and the space velocity is 30,000 ml / g·h. The reaction results are shown in Table 1.

[0148] Comparative Example 1

[0149] 1) Prepare Ru nano-sol.

[0150] Dissolve 20 g of RuCl₃ in 80 g of 10 wt% hydrochloric acid aqueous solution to obtain Ru solution A with a Ru mass content of 10 wt%. Weigh 1 g of 10 wt% Ru solution A, add 50 mL of sodium hydroxide ethylene glycol solution with a molar concentration of 0.25 mol L -1 , stir at room temperature for 1 h, then transfer it to an oil bath at 160 °C, and stir and react for 1 h under argon atmosphere protection to obtain Ru sol (Ru mass concentration is 2 mg mL -1 ).

[0151] 2) Prepare Ru / S sample.

[0152] Weigh 1.0 g of Al₂O₃ support and add it to a beaker containing 100 mL of ethylene glycol, stir in a water bath at 80 °C for 20 min to form an Al₂O₃ ethylene glycol suspension. Measure 5 ml of Ru sol with a Ru mass concentration of 2 mg mL -1 , and add it dropwise to the vigorously stirred Al₂O₃ support suspension. React at 80 °C for 3 h, age for 1 h, filter and wash while it is hot, and then place it in an oven at 80 °C to dry for 6 h to obtain the Ru / Al₂O₃ sample. Then, perform hydrogen reduction on it at a temperature of 600 °C, with a heating rate from room temperature to the reduction temperature of 5 °C / min, a hydrogen volume space velocity of 2000 h -1 , and a pressure of atmospheric pressure, and a reduction time of 1 h. The catalyst obtained is denoted as 1% Ru / Al₂O₃.

[0153] Reaction conditions for ammonia decomposition using the catalyst: ammonia concentration is 99.9%, fixed-bed reactor, reaction temperature is 400°C to 500°C, and space velocity is 30,000 ml / g·h. The reaction results are shown in Table 1.

[0154] Comparative Example 2

[0155] Weigh 1.0 g of Al2O3 support, weigh 0.3113 g of NiNO3 and dissolve it in 2 g of deionized water to prepare a mixed solution with a Ni mass concentration of 1.2 wt%. Drop it into the Al2O3 support and mix it evenly. Impregnate at room temperature for 12 h, dry at 80°C for 12 h, and calcine in an air atmosphere at 300°C for 4 h, with a Ni mass content of 10%. Then, carry out hydrogen reduction at a temperature of 600°C, with a heating rate from room temperature to the reduction temperature of 5°C / min and a hydrogen volume space velocity of 2000 h -1 , at atmospheric pressure, and the reduction time is 1 h. The catalyst obtained is denoted as 10% Ni / Al2O3.

[0156] Reaction conditions for ammonia decomposition using the catalyst: ammonia concentration is 99.9%, fixed-bed reactor, reaction temperature is 400°C to 500°C, and space velocity is 30,000 ml / g·h. The reaction results are shown in Table 1.

[0157] Analysis of the results of the examples:

[0158] From the data analysis in Table 1, it can be seen that the Ru-X / S catalyst prepared using Ru sol and alkali metals or alkaline earth metals has good activity in the ammonia decomposition reaction. For the 1% Ru-3% K / Al2O3 catalyst, ammonia conversion > 99% can be achieved at 500°C. High-efficiency decomposition of ammonia can be achieved under high space velocity and low temperature conditions. And the support used is cheap and easily available, enabling large-scale preparation of the catalyst and having the potential for industrial application.

[0159] Table 1 Reaction performance of ammonia decomposition on different catalysts

[0160]

[0161]

[0162] The above 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 as above with preferred embodiments, 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 ammonia decomposition catalyst, characterized in that, The ruthenium-based ammonia decomposition catalyst comprises a support, and an active component and a promoter component supported on the support; The active component is Ru; The promoter component is a metal oxide; The metal element in the metal oxide is selected from at least one of Li, K, Cs, Ca, Sr, Ba, Rb, and Na; The support is selected from at least one of Al2O3, SiO2, CeO2, MgO, and TiO2.

2. The ruthenium-based ammonia decomposition catalyst according to claim 1, wherein The active component accounts for 0.01-10 wt.% of the mass of the ruthenium-based ammonia decomposition catalyst; Preferably, the promoter component accounts for 1-10 wt.% of the mass of the nickel-based ammonia decomposition catalyst; Preferably, the support accounts for 80-98.99 wt.% of the mass of the nickel-based ammonia decomposition catalyst.

3. The preparation method of the ruthenium-based ammonia decomposition catalyst according to any one of claims 1 to 2, characterized in that, The preparation method comprises the following steps: (1) In an inert atmosphere, a mixture I containing a ruthenium precursor salt and an ethylene glycol solution containing an alkali is subjected to Reaction I to obtain a Ru nano-sol; (2) A mixture II containing the Ru nano-sol and an ethylene glycol solution containing a support is subjected to Reaction II, aging, and drying I to obtain a matrix containing the support; (3) A mixture III containing the matrix containing the support and a metal salt solution is impregnated, dried II, calcined, and reduced to obtain the ruthenium-based ammonia decomposition catalyst.

4. The preparation method according to claim 3, wherein In step (1), the ruthenium precursor salt is selected from at least one of ruthenium chloride, ruthenium nitrate, and ruthenium acetylacetonate; Preferably, in step (1), the alkali in the ethylene glycol solution containing an alkali is selected from sodium hydroxide and / or potassium hydroxide; Preferably, in step (1), the inert atmosphere is selected from nitrogen and / or argon; Preferably, in step (1), the concentration of the ethylene glycol solution containing an alkali is 0.2 mol / L-1 mol / L, and the concentration of the ethylene glycol solution containing an alkali is based on the molar concentration of the alkali; Preferably, in step (1), the concentration of the Ru nano-sol is 2 mg / mL-20 mg / mL, and the concentration of the Ru nano-sol is based on the mass content of the Ru element; Preferably, in step (1), the temperature of Reaction I is 130-180 °C, and the time of Reaction I is 1-12 h.

5. The preparation method according to claim 3, wherein In step (2), the concentration of the ethylene glycol solution containing a support is 10 g / L-50 g / L, and the concentration of the ethylene glycol solution containing a support is based on the mass concentration of the support; Preferably, in step (2), the temperature of Reaction II is 60-80 °C, and the time of Reaction II is 1-4 h; Preferably, in step (2), the aging time is 1-4 h; Preferably, in step (2), the temperature of drying I is 60-120 °C, and the time of drying I is 4-12 h.

6. The preparation method according to claim 3, characterized in that, In step (3), the metal salt solution is selected from at least one of nitrates and chlorides containing a metal element; Preferably, the metal element is selected from at least one of Li, K, Cs, Ca, Sr, Ba, Rb, and Na; Preferably, the mass concentration of the metal salt solution is 0.1 wt%-10 wt%, and the mass concentration of the metal salt solution is based on the mass content of the metal element.

7. The preparation method according to claim 3, characterized in that, In step (3), the impregnation time is 0.5-48 h; Preferably, in step (3), the temperature of the second drying is 60-120°C, and the time of the second drying is 4-12 h; Preferably, the temperature of the roasting is 200-400°C, and the time of the roasting is 4-12 h; Preferably, the reduction is a high-temperature gas-phase reduction method, and the reducing atmosphere for the reduction is selected from ammonia gas and / or hydrogen gas; Preferably, the volumetric space velocity of the reducing atmosphere for the reduction is 100 to 3600 h -1 ; Preferably, the heating rate during the reduction is 1-10°C / min, the reduction temperature is 200-600°C, and the reduction time is 1-48 h.

8. Use of the ruthenium-based ammonia decomposition catalyst according to any one of claims 1 to 2 in ammonia decomposition.

9. The application according to claim 8, characterized in that, The reaction space velocity of the ammonia decomposition is 200-60000 ml / g·h.

10. The application according to claim 8, wherein The reaction temperature of the ammonia decomposition is 300-900°C; Preferably, the reaction temperature of the ammonia decomposition is 350-500°C.

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