Ammonia decomposition hydrogen production catalyst, preparation method and application thereof

Abstract

The application discloses a kind of ammonia decomposition hydrogen production catalyst and its preparation method and application, including the following steps: aluminum source, silicon source, sodium hydroxide and water are mixed to configure gel, SOD molecular sieve is obtained after high-temperature crystallization;SOD molecular sieve is mixed with ruthenium salt, and the SOD molecular sieve loaded with ruthenium is obtained by high-temperature heat treatment and shaping.Ruthenium is the active metal of catalyst, and SOD cage is rich in stable sodium ion, which provides electrons to metal ruthenium through sodium ion, enhances the activation of ammonia to metal ruthenium, and reduces the temperature of ammonia complete decomposition;The preparation method of the catalyst of the application is simple, the catalyst prepared has a lower operating temperature, and avoids the problem that the operating temperature of ruthenium-based catalyst in the prior art is too high and is easy to deactivate.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydrogen production by ammonia decomposition catalyst, and particularly relates to a hydrogen production by ammonia decomposition catalyst, a preparation method and application thereof. BACKGROUND

[0002] When traditional fossil fuels are used by combustion, chemical processing, etc., a large amount of carbon dioxide will be inevitably released, causing environmental problems. Under the demand of global carbon reduction, the development and utilization of non-carbon new energy has very great significance. Hydrogen (H) energy is considered as an ultimate clean fuel because of its high energy density (120 megajoules / kilogram) and the characteristics of only producing water and not emitting carbon dioxide during combustion. However, the wide flammability range and low ignition energy (0.17 kilojoules / mole) of hydrogen make it face great risks during transportation and storage. Limited by the lack of effective storage and transportation (steel cylinder storage of H2 requires high pressure of about 700 bar), the direct use of hydrogen has been greatly hindered. Therefore, the development of a "hydrogen carrier" with low cost, high density, high storage efficiency and on-demand hydrogen production is considered as the key to solving the problem of effective utilization of hydrogen energy.

[0003] Ammonia (NH3) contains 17.8wt% H, and can produce nitrogen (N2) and hydrogen (H2) with a volume ratio of 1:3 by decomposition. Compared with carbon-based hydrogen carriers (such as methanol, methane, etc.) that produce carbon dioxide during hydrogen production, ammonia has been widely concerned due to its high hydrogen production and zero carbon emission (Valera-Medina, A. et al, Energy. Fuels. 2021, 35, 6964). Hydrogen production by ammonia decomposition provides a new possibility for the low-carbon transformation of hydrogen energy economy (Goetsch, D. A. et al, WO Patent, 2001, 0187770). For more than 20 years, the development of high-efficiency catalysts is the key to hydrogen production by ammonia decomposition technology. Ruthenium-based catalysts and ruthenium-based catalysts are currently the main research fields (Schuth, R. et al, Energy. Environ. Sci, 2012, 5, 6278). Ruthenium catalysts have high ammonia decomposition activity and can decompose ammonia at 350-500℃ (CN107876796B; Nagaoka, K. et al, Sci Advs, 2017, 3, e1602747), but the scarcity and high cost of Ru limit its large-scale commercial application. Therefore, the preparation of Ru catalysts with low production cost, low operating temperature, high conversion rate and long service life is the key to realizing large-scale commercial application of hydrogen production by ammonia catalytic decomposition. SUMMARY

[0004] The technical problem solved by the present application is to provide an ammonia decomposition hydrogen production catalyst, a preparation method and application thereof, wherein SOD molecular sieves are first prepared, then ruthenium is loaded on the SOD molecular sieves to obtain a ruthenium-based ammonia decomposition hydrogen production catalyst, the catalyst has high stability and can be used continuously, and the temperature for ammonia decomposition hydrogen production is reduced, thereby reducing the cost and effectively avoiding the problems of high operating temperature and high cost of the ruthenium-based catalyst.

[0005] To solve the above technical problem, the present application provides, in one aspect, a preparation method of an ammonia decomposition hydrogen production catalyst, comprising the following steps:

[0006] S1, mixing an aluminum source, a silicon source, sodium hydroxide and water to configure a gel, and obtaining SOD molecular sieves after high-temperature crystallization;

[0007] S2, mixing the SOD molecular sieves with a ruthenium salt, and obtaining a ruthenium-loaded SOD molecular sieve through high-temperature heat treatment and molding;

[0008] The mass fraction of ruthenium in the ruthenium-loaded SOD molecular sieve is 0.5% to 20%.

[0009] The SOD molecular sieves are prepared by the reaction of an aluminum source, a silicon source and sodium hydroxide, the molecular sieves have a high specific surface area, can stabilize the surface metal nanoparticles, and can adjust the surface chemistry by increasing the active site density to promote the diffusion of intermediates in the reaction process. At the same time, in this reaction, increasing the basicity of the catalyst can promote the dissociation of the nitrogen-hydrogen bond, thereby improving the catalytic activity. The SOD molecular sieves stand out among numerous molecular sieves due to their low silicon-aluminum ratio and high alkalinity. In the synthesis of the SOD molecular sieves, a large number of sodium ions are contained in the cage, and at the same time, the diameter of the SOD cage is only 0.3 nanometers, which can well fix the sodium ions. After the SOD molecular sieves are loaded with ruthenium, the sodium ions can provide electrons to the metal ruthenium, accelerate the activation of the metal ruthenium, and further reduce the temperature for complete decomposition of ammonia. Experimental results show that the reaction activity of the molecular sieves with high alkali metal concentration is higher than that of the catalyst without adding alkali metal.

[0010] Therefore, the Ru-SOD catalyst can obtain a good conversion rate at a relatively low temperature (500℃). Through the above means, the problems of high operating temperature and easy deactivation of the ruthenium-based catalyst are effectively avoided. In addition, the preparation method is simple and can realize large-scale production.

[0011] Further, in S2, the mixing method is one of co-precipitation, ball milling and impregnation.

[0012] Further, the co-precipitation is specifically as follows: the SOD molecular sieves are mixed with a ruthenium salt aqueous solution with a mass concentration of 0.5 mol / L to 2 mol / L, stirred under the condition that the pH is 8.5 to 9.5, and then filtered, washed and dried after precipitation.

[0013] Further, the impregnation is specifically: stirring and mixing the SOD molecular sieve, the ruthenium salt and the deionized water, and then drying.

[0014] Further, when the mixing mode is co-precipitation or impregnation, the high-temperature heat treatment is calcination at 300-600 DEG C and reduction in hydrogen atmosphere at 500-600 DEG C; when the mixing mode is ball milling, the high-temperature heat treatment is reduction in hydrogen atmosphere at 500-600 DEG C. Preferably, the calcination at 300-600 DEG C is calcination at 300 DEG C for 1h and calcination at 600 DEG C for 3h; the reduction in hydrogen atmosphere at 500-600 DEG C is preferably reduction at 550 DEG C for 2h.

[0015] Further, in S2, the ruthenium salt is one or more of ruthenium nitrate hexahydrate, ruthenium carbonate and ruthenium chloride.

[0016] Further, in S1, the aluminum source is one or more of sodium aluminate, aluminum hydroxide and aluminum isopropoxide.

[0017] Further, in S1, the silicon source is one or more of sodium silicate nonahydrate, silica gel and fumed silica.

[0018] Further, in S1, the molar ratio of sodium, aluminum and silicon in the SOD molecular sieve is 7.5:1:(1-4).

[0019] Further, in S1, the temperature of the high-temperature crystallization is 80-120 DEG C, and the pressure is normal pressure.

[0020] Further, the forming is sieving after tabletting.

[0021] The second aspect of the application provides the ammonia decomposition hydrogen production catalyst prepared by the preparation method of the first aspect.

[0022] The third aspect of the application provides the application of the catalyst in geothermal aspect, the catalyst is loaded in a fixed bed reactor, ammonia passes through the catalyst bed, and the decomposition reaction is carried out at 200-600 DEG C.

[0023] Further, the mass space velocity of the decomposition reaction is 600-60000 mL·h -1 ·g -1 .

[0024] The beneficial effects of the application are:

[0025] The preparation method of the ammonia decomposition hydrogen production ruthenium catalyst is simple, which greatly reduces the preparation difficulty of the catalyst. At the same time, the catalyst has a lower operating temperature, which avoids the problem of high operating temperature and easy deactivation of the ruthenium-based catalyst in the prior art.

[0026] The SOD molecular sieve used in the present application has a six-membered ring window with a diameter of about 0.7 nm. The alkali metal ions can be protected to the maximum extent and prevented from being lost. The SOD cage contains a large amount of sodium ions, and the sodium ions can provide a large amount of electrons to the metal ruthenium position, accelerate the activation of the metal ruthenium, and further reduce the temperature of the complete decomposition of ammonia. By using the SOD molecular sieve to load ruthenium, the effective breaking of the nitrogen-hydrogen bond in the ammonia molecule is promoted in the ammonia decomposition reaction system, the forward progress of the equilibrium reaction is accelerated, and a better conversion rate can be obtained at a lower temperature. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a comparison chart of X-ray diffraction spectra of the SOD and Ru / SOD catalysts of the present application;

[0028] Figure 2 is a comparison chart of X-ray diffraction spectra of the catalyst of the present application before and after the ammonia decomposition reaction. DETAILED DESCRIPTION

[0029] The present application will be further described below in conjunction with the drawings and specific examples, so that those skilled in the art can better understand the present application and implement it, but the examples are not limiting to the present application.

[0030] Example 1

[0031] 44.16 g of ultrapure water, 2.731 g of sodium metaaluminate, 6.309 g of sodium hydroxide, and 9.474 g of sodium silicate nonahydrate are mixed and stirred to prepare a gel, and the components and molar ratio in the gel are 7.5 (Na2O): 1.0 (Al2O3): 2.0 (SiO2): 165 (H2O). Then, the gel is crystallized at 100℃ for 12 h, and after the precipitate is centrifuged, washed, and dried, the SOD molecular sieve is obtained.

[0032] According to the mass percentage of ruthenium ions in the molecular sieve catalyst being 1%, ruthenium chloride is taken and added to deionized water to prepare a 1 mol / L ruthenium chloride solution (metal precursor solution A); sodium hydroxide is taken and added to deionized water to prepare a 0.2 mol / L solution. The SOD molecular sieve is mixed with the solution A in a stirrer, stirred at a speed of 600 r / min, and 0.2 mol / L NaOH solution is added dropwise to the mixture to adjust the pH value of the solution in the beaker to 9. Continue to stir and age for 2 h, filter and wash, then dry in an oven, calcine at 600℃ for 3 h, reduce at 550℃ in a hydrogen atmosphere for 2 h, press into a tablet, sieve, and obtain the 7% Ru-SOD-DP-Na catalyst by a two-step precipitation method.

[0033] The catalyst was loaded in a fixed bed reactor to catalytically evaluate the ammonia decomposition reaction in the fixed bed reactor. The specific conditions are as follows: 0.5 g of 1% Ru-SOD-DP-Na catalyst (40-60 mesh), the reaction temperature is 200-500°C, the reaction pressure is normal pressure, the reaction gas ammonia flow is 50 ml / min, the mass space velocity is 6000 mL·h -1 ·g -1 The 1% Ru-SOD-DP-Na catalyst was heated to 200°C under an inert gas atmosphere, and then ammonia was introduced for reaction. The temperature was increased by 50°C every hour until 500°C to end the reaction. The conversion rate of ammonia at different temperatures was detected.

[0034] Example 2

[0035] 44.16 g of ultrapure water, 2.731 g of sodium metaaluminate, 6.309 g of sodium hydroxide, and 9.474 g of sodium silicate nonahydrate were mixed and stirred to prepare a gel. The components and molar ratio in the gel were 7.5 (Na2O): 1.0 (Al2O3): 2.0 (SiO2): 165 (H2O). Then, crystallization was carried out at 100°C for 12 h to obtain a mixed solution of SOD molecular sieve and alkaline solution. The pH was adjusted to 9 to obtain solution A.

[0036] According to the molar ratio of 1% of ruthenium ions to the mass percentage of the molecular sieve catalyst, ruthenium chloride was added to deionized water to prepare a 1 mol / L ruthenium chloride solution (metal precursor solution B). Solution B was added to solution A with pH = 9, stirred at a speed of 600 r / min, aged for 2 h, filtered and washed, then placed in an oven for drying, calcined at 600°C for 3 h, reduced at 550°C under a hydrogen atmosphere for 2 h, pressed into a tablet, sieved, and a 1% Ru-SOD-ODP catalyst was obtained by one-step precipitation method.

[0037] The catalyst was loaded in a fixed bed reactor to catalytically evaluate the ammonia decomposition reaction in the fixed bed reactor. The specific conditions are as follows: 0.5 g of 1% Ru-SOD-DP-Na catalyst (40-60 mesh), the reaction temperature is 200-500°C, the reaction pressure is normal pressure, the reaction gas ammonia flow is 50 ml / min, the mass space velocity is 6000 mL·h -1 ·g -1 The 1% Ru-SOD-DP-Na catalyst was heated to 200°C under an inert gas atmosphere, and then ammonia was introduced for reaction. The temperature was increased by 50°C every hour until 500°C to end the reaction. The conversion rate of ammonia at different temperatures was detected.

[0038] Example 3

[0039] Take 44.16 g of ultrapure water, 2.731 g of sodium metaaluminate, 6.309 g of sodium hydroxide, 9.474 g of sodium silicate nonahydrate, mix and stir to prepare a gel, the components in the gel and the molar ratio are 7.5 (Na2O): 1.0 (Al2O3): 2.0 (SiO2): 165 (H2O). Then crystallize at 100℃ for 12h, centrifuge, wash and dry the precipitate to obtain SOD molecular sieve.

[0040] According to the mass percentage of ruthenium ions in the molecular sieve catalyst being 1%, take ruthenium chloride and add it to deionized water to prepare a 1 mol / L ruthenium chloride solution (metal precursor solution A); mix the SOD molecular sieve with solution A in a stirrer, stir at a speed of 600 r / min, and add 0.2 mol / L ammonia solution dropwise to the mixture to adjust the pH value of the solution in the beaker to 9. Continue to stir for 2h, filter and wash, then dry in an oven, calcine at 600℃ for 3h, reduce at 550℃ in a hydrogen atmosphere for 2h, press into tablets, sieve, and obtain 1% Ru-SOD-DP catalyst by two-step precipitation method.

[0041] The catalyst is loaded in a fixed bed reactor to catalytically evaluate the ammonia decomposition reaction in the fixed bed reactor. The specific conditions are as follows: 0.5g of 1% Ru-SOD-DP catalyst (40-60 mesh), reaction temperature is 200-500℃, reaction pressure is atmospheric pressure, reaction gas ammonia flow is 50ml / min, mass space velocity is 6000mL·h -1 ·g -1 The 7% Ru-SOD-DP catalyst is heated to 200℃ in an inert gas atmosphere, and then ammonia gas is introduced for reaction. The temperature is increased by 50℃ every hour until 500℃, and the reaction is stopped. The conversion rate of ammonia gas at different temperatures is detected.

[0042] Example 4

[0043] Take 44.16 g of ultrapure water, 2.731 g of sodium metaaluminate, 6.309 g of sodium hydroxide, 9.474 g of sodium silicate nonahydrate, mix and stir to prepare a gel, the components in the gel and the molar ratio are 7.5 (Na2O): 1.0 (Al2O3): 2.0 (SiO2): 165 (H2O). Then crystallize at 100℃ for 12h, centrifuge, wash and dry the precipitate to obtain SOD molecular sieve.

[0044] According to the mass percentage of ruthenium ions in the molecular sieve catalyst being 1%, take 0.21 g of ruthenium nitrate hexahydrate and 1.5 g of SOD molecular sieve and put them into a ball mill device for 1h to obtain a uniformly mixed powder, which is placed in a reduction furnace and reduced at 550℃ in a hydrogen atmosphere for 2h, then pressed into tablets, sieved, and 1% Ru-SOD-QM catalyst is obtained by ball milling method.

[0045] The catalyst was loaded in a fixed bed reactor to catalytically evaluate the ammonia decomposition reaction in the fixed bed reactor. The specific conditions are as follows: 0.5 g of 1% Ru-SOD-QM catalyst (40-60 mesh), the reaction temperature is 200-500°C, the reaction pressure is normal pressure, the reaction gas ammonia flow is 50 ml / min, the mass space velocity is 6000 mL·h -1 ·g -1 The 1% Ru-SOD-QM catalyst was heated to 200°C under an inert gas atmosphere, and then ammonia was introduced for reaction. The temperature was increased by 50°C every hour until 500°C, and the reaction was stopped. The conversion rate of ammonia at different temperatures was detected.

[0046] Example 5

[0047] 44.16 g of ultrapure water, 2.731 g of sodium metaaluminate, 6.309 g of sodium hydroxide, and 9.474 g of sodium silicate nonahydrate were mixed and stirred to prepare a gel. The components and molar ratio in the gel were 7.5 (Na2O): 1.0 (Al2O3): 2.0 (SiO2): 165 (H2O). After crystallization at 100°C for 12 h, the precipitate was centrifuged, washed, and dried to obtain SOD molecular sieve.

[0048] According to the mass percentage of ruthenium ions in the molecular sieve catalyst being 1%, 0.21 g of ruthenium nitrate hexahydrate was dissolved in 0.56 g of deionized water to obtain solution A. Solution A was added dropwise to 1.5 g of SOD molecular sieve while stirring, and then dried at 80°C for 10 h, calcined at 600°C for 3 h, and reduced at 550°C for 2 h in a hydrogen atmosphere. The product was pressed into a tablet, sieved, and then impregnated to obtain 1% Ru-SOD-IMP catalyst.

[0049] The catalyst was loaded in a fixed bed reactor to catalytically evaluate the ammonia decomposition reaction in the fixed bed reactor. The specific conditions are as follows: 0.5 g of 1% Ru-SOD-IMP catalyst (40-60 mesh), the reaction temperature is 200-500°C, the reaction pressure is normal pressure, the reaction gas ammonia flow is 50 ml / min, the mass space velocity is 6000 mL·h -1 ·g -1 The 1% Ru-SOD-IMP catalyst was heated to 200°C under an inert gas atmosphere, and then ammonia was introduced for reaction. The temperature was increased by 50°C every hour until 500°C, and the reaction was stopped. The conversion rate of ammonia at different temperatures was detected.

[0050] Examples 6-9

[0051] The difference between Example 1 and the present example is that the mass percentage of ruthenium ions in the molecular sieve catalyst is different, and the other steps are the same.

[0052] Examples 10-12

[0053] The difference from Example 3 is that the mass space velocity is different, and the other steps are the same.

[0054] Examples 13-16

[0055] The difference from Example 2 is that the mass percentage of ruthenium ions in the molecular sieve catalyst is different, and the other steps are the same.

[0056] The SOD molecular sieve and the SOD molecular sieve catalyst loaded with 1% Ru in Example 7 were subjected to X-ray analysis, as shown in Figure 1. Figure 1 After loading the metal Ru, the diffraction peak position of the SOD did not change, and no diffraction peak of the metal oxide appeared, indicating that the loading of Ru by the preparation method of the application did not destroy the structural characteristics of the carrier itself. The catalysts before and after the decomposition of ammonia to produce hydrogen were subjected to X-ray analysis, and it was found that the diffraction peaks of the catalysts before and after the catalytic reaction did not change, indicating that the framework of the molecular sieve did not change during the entire catalytic process, maintained the original morphology, and had good stability. Figure 2

[0057] Comparative Example 1

[0058] The difference from Example 1 is that 49.5 g of ultrapure water, 4.0985 g of sodium metaaluminate, 0.3474 g of sodium hydroxide, and 14.21 g of sodium silicate nonahydrate are mixed and stirred to prepare a gel, and the components and molar ratio in the gel are 3.165 (Na2O): 1.0 (Al2O3): 2.0 (SiO2): 160 (H2O). Then, the precipitate is centrifuged, washed, and dried after crystallization at 100°C for 4h to obtain 4A molecular sieve.

[0059] The other steps are the same, and the 1% Ru-A-DP-Na catalyst is prepared, and the conversion rate is detected by the same steps.

[0060] Comparative Example 2

[0061] The difference from Example 1 is that 45 g of ultrapure water, 3.2788 g of sodium metaaluminate, 4.2105 g of sodium hydroxide, and 11.368 g of sodium silicate nonahydrate are mixed and stirred to prepare a gel, and the components and molar ratio in the gel are 5.5 (Na2O): 1.0 (Al2O3): 1.65 (K2O): 2.0 (SiO2): 143 (H2O). Then, the precipitate is centrifuged, washed, and dried after crystallization at 70°C for 6h and at 95°C for 3h to obtain 13X molecular sieve.

[0062] The other steps are the same, and the 1% Ru-X-DP-Na catalyst is prepared, and the conversion rate is detected by the same steps.

[0063] Comparative Example 3

[0064] ​The difference from example 1 is that 25.4 g of ultrapure water, 0.18 g of sodium metaaluminate, 0.072 g of sodium hydroxide, 21.26 g of tetraethyl orthosilicate, and 12.2 g of tetrapropylammonium hydroxide (TPAOH) are mixed and stirred to prepare a gel, and the components and molar ratio in the gel are 100 (SiO2): 1.1 (Al2O3): 2 (Na2O): 1.0 (TPAOH): 1920 (H2O). Then, the gel is crystallized at 170 DEG C for 36 h, and after the precipitate is centrifuged, washed, and dried, ZSM-5 zeolite is obtained.

[0065] The other steps are unchanged, and a 1% Ru-ZSM-5-DP-Na catalyst is prepared, and the conversion rate is detected by the same steps.

[0066] Comparative example 4

[0067] The difference from example 1 is that 26.9 g of ultrapure water, 0.91 g of sodium metaaluminate, 0.8 g of sodium hydroxide, 39.05 g of silica gel, and 2.72 g of piperidine (PI) are mixed and stirred to prepare a gel, and the components and molar ratio in the gel are 20 (SiO2): 0.55 (Al2O3): 2.1 (Na2O): 3.2 (PI): 280 (H2O). After stirring for 0.5 h, the gel is crystallized at 160 DEG C for 40 h, and after the precipitate is centrifuged, washed, dried, and calcined at 550 DEG C, FER zeolite is obtained.

[0068] The other steps are unchanged, and a 1% Ru-FER-DP-Na catalyst is prepared, and the conversion rate is detected by the same steps.

[0069] The preparation parameters of each example and comparative example and the conversion rates at different temperatures are shown in Table 1.

[0070] Table 1

[0071]

[0072] It can be seen from examples 1-5 that the catalyst prepared by the preparation method of example 1 has better catalytic effect in the hydrogen production by ammonia decomposition, and the conversion rate of the catalyst of example 1 is 100% at 500 DEG C.

[0073] It can be seen from the comparison of example 1, examples 6-9, and examples 2, examples 13-16 that the increase of the mass fraction of ruthenium in the zeolite catalyst can improve the conversion rate of ammonia, and for the preparation method of example 1, the conversion rate can reach 100% at 500 DEG C when the mass fraction of ruthenium is 1% or more, and for the preparation method of example 2, the conversion rate can reach 100% at 500 DEG C when the mass fraction of ruthenium is 2% or more. It can be seen that the zeolite loaded with ruthenium in the present application has good catalytic effect, significantly reduces the operating temperature of the ruthenium-based catalyst, and reduces the cost of hydrogen production by ammonia decomposition.

[0074] From Example 3, Examples 10-12, it can be seen that as the mass space velocity increases during the decomposition reaction, the conversion rate decreases, in Example 10, at a mass space velocity of 3000 mL·h -1 ·g -1 , the conversion rate at 500 DEG C is 97.394%.

[0075] From Example 1, Comparative Examples 1-4, it can be seen that when other molecular sieves are used in Comparative Examples 1-4, the catalytic efficiency of the prepared ruthenium-loaded molecular sieve catalyst in the hydrogen production by ammonia decomposition is relatively poor, the conversion rate at 500 DEG C is less than 85%, and it can be seen that the SOD molecular sieve loaded with ruthenium and rich in sodium ions has excellent catalytic effect.

[0076] The above-described examples are only preferred examples for fully illustrating the present application, and the protection scope of the present application is not limited thereto. Any equivalent replacement or transformation made by the person skilled in the art on the basis of the present application is within the protection scope of the present application. The protection scope of the present application is subject to the claims.

Claims

1. Use of a catalyst in the hydrogen production by ammonia decomposition, characterized in that, The preparation method of the catalyst comprises the following steps: S1, mixing an aluminum source, a silicon source, sodium hydroxide and water to configure a gel, and crystallizing at high temperature to obtain a SOD molecular sieve rich in sodium ions; S2, mixing the SOD molecular sieve with a ruthenium salt, and performing high-temperature heat treatment and molding to obtain a SOD molecular sieve loaded with ruthenium; The mass fraction of ruthenium in the SOD molecular sieve loaded with ruthenium is 0.1%-20%.

2. Use according to claim 1, wherein In S2, the mixing method is one of co-precipitation, ball milling and impregnation.

3. Use according to claim 2, wherein the compound is ###0002### The co-precipitation is specifically as follows: mixing the SOD molecular sieve with a ruthenium salt aqueous solution with a mass concentration of 0.5 mol / L-2 mol / L, stirring under the condition that the pH is 8.5-9.5, filtering, washing and drying after precipitation.

4. The use according to claim 2, wherein the compound is ###0002### The impregnation is specifically as follows: mixing the SOD molecular sieve, the ruthenium salt and deionized water after stirring, and drying.

5. The use according to claim 2, wherein the compound is ###0002### When the mixing method is co-precipitation or impregnation, the high-temperature heat treatment is calcination at 300-600 DEG C and reduction in a hydrogen atmosphere at 500-600 DEG C; when the mixing method is ball milling, the high-temperature heat treatment is reduction in a hydrogen atmosphere at 500-600 DEG C.

6. The use according to claim 1, wherein In S2, the ruthenium salt is one or more of ruthenium nitrate hexahydrate, ruthenium carbonate and ruthenium chloride.

7. The use according to claim 1, wherein In S1, the molar ratio of sodium, aluminum and silicon in the SOD molecular sieve is 7.5:1:(1-4).

8. The use according to claim 1, wherein The catalyst is loaded in a fixed bed reactor, ammonia passes through the bed of the catalyst, and a decomposition reaction is carried out at 200-600 DEG C.

9. The use according to claim 1, wherein The mass space velocity of the decomposition reaction is 600-60000 mL·h -1 ·g -1 .

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