Ammonia synthesis catalyst, production method, and ammonia synthesis method

Abstract

This invention discloses an ammonia synthesis catalyst, its manufacturing method, and an ammonia synthesis method. The ammonia synthesis catalyst is a metal-supported catalyst, comprising a support and an active metal supported on the support. The support is an electron-containing compound containing a pinned phase, which is a transition metal oxide or a transition metal nitride. The active metal is a transition metal. The metal-supported catalyst of this invention exhibits high ammonia synthesis activity even under low reaction temperature and low reaction pressure conditions, and possesses excellent durability, making it particularly suitable as a catalyst for ammonia synthesis.

Description

Technical Field

[0001] This invention belongs to the field of ammonia synthesis technology, and relates to an ammonia synthesis catalyst, a manufacturing method, and an ammonia synthesis method. Specifically, it relates to a metal-supported ammonia synthesis catalyst, a manufacturing method, and an ammonia synthesis method that uses an electron-supported compound containing a pinned phase as a carrier and a transition metal as the active metal. Background Technology

[0002] Ammonia is one of the world's most widely traded chemicals, with a mature production, transportation, and storage system, and it has important applications in agriculture, medicine, and chemical industries. With increasing environmental pollution and climate change, the global demand for clean, zero-carbon energy is growing. Ammonia, as a zero-carbon hydrogen storage carrier, has demonstrated enormous potential.

[0003] The Haber-Bosch process is the most widely used ammonia production technology. It involves synthesizing ammonia by reacting nitrogen and hydrogen under high temperature and pressure conditions (300–500°C, 200–300 atm) using an iron-based catalyst. However, the Haber-Bosch process suffers from high energy consumption and high carbon emissions, consuming 1–2% of the world's total energy annually and generating approximately 1.5% of total greenhouse gas emissions annually. Therefore, developing efficient catalysts to achieve ammonia synthesis at lower temperatures and pressures is of great significance for addressing the energy consumption, pollution, and safety issues in the ammonia synthesis industry.

[0004] Electron compounds are salts with specific crystal structures. Their characteristic feature is that some electrons can act independently as anions, residing in interstitial lattice spaces, while others move freely within the framework of cations. Therefore, electron compounds generally exhibit extremely strong reducing properties. Based on these unique properties, electron compounds can be used as catalyst supports to modulate the electronic structure of active metal centers. Existing research has shown that when electron compounds are used as catalyst supports in ammonia synthesis, after the support transfers electrons to the active metal, the electrons shift from the metal to the N2 antibonding orbitals, making it easier to break the nitrogen-nitrogen triple bond of N2. H2 dissociates into H on the active metal, which then enters the electron compound and reacts with the captured electrons to form H2. - H atoms that overflow onto the surface of the electron-carrying compound react with N atoms to form NH3. The easier cleavage of the nitrogen-nitrogen triple bond in N2 is key to the increased reaction rate and reduced reaction conditions achieved by using an electron-carrying compound. Therefore, electron-carrying compounds are a promising carrier material.

[0005] However, electron-supported catalysts suffer from insufficient stability during long-term use. Because the active metal and the electron compound rely on van der Waals forces or weak electrostatic interactions, they lack strong metallic or covalent bonds. Furthermore, the mismatch in lattice constants at the interface leads to lattice stress and defects, further weakening the bond between them. This results in the active metal easily peeling off from the support surface under high temperature and high pressure conditions, affecting the performance and lifespan of the catalyst. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a metal-supported ammonia synthesis catalyst with good selectivity and stability, using an electronic compound containing a pinned phase (the pinned phase is a transition metal oxide / nitride) as a carrier and a transition metal as the active metal, along with its manufacturing method and ammonia synthesis method. In the ammonia synthesis process, this catalyst not only reduces the reaction temperature and pressure but also achieves a longer service life.

[0007] This invention discloses an ammonia synthesis catalyst, which is a metal-supported catalyst, comprising a support and an active metal supported on the support;

[0008] The carrier is an electronic compound containing a pinned phase, wherein the pinned phase is a transition metal oxide or a transition metal nitride;

[0009] The active metal is a transition metal, preferably an elemental transition metal.

[0010] As a further improvement of the present invention, the electronic compound is C 12 One or a combination of A7, Y5Si3, LaScSi, LaRuSi, LaNiSi, LaCoSi, LiH, La3AlN, Ba-Ca(NH2)2, CaFH, Ca2N, Sr2N, Y2C, C5A3, C3A, Gd2C, Tb2C, Dy2C, Ho2C, and Er2C.

[0011] As a further improvement of the present invention, the transition metal involved in the pinned phase and the active metal includes at least one of Ru, Co, Ni, Fe, and Mo.

[0012] As a further improvement of the present invention, the content of the stapled phase in the carrier is 0.01wt% to 2wt%.

[0013] As a further improvement of the present invention, the loading of the active metal relative to the carrier is 0.01wt% to 50wt%.

[0014] This invention also discloses a method for preparing an ammonia synthesis catalyst, comprising:

[0015] Step 1: Prepare an electron compound containing a pinned phase to obtain a carrier;

[0016] Step 2: Load the transition metal onto the carrier;

[0017] Step 3: Reduce the carrier loaded with transition metal.

[0018] As a further improvement of the present invention, in step 1, an electronic compound containing a pinned phase is prepared by hydrothermal synthesis, single crystal pulling, sol-gel method, combustion synthesis or coprecipitation method.

[0019] As a further improvement of the present invention

[0020] A method for manufacturing an electronic compound containing a pinned phase via a hydrothermal process includes: mixing a precursor of the electronic compound with a transition metal oxide / transition metal nitride and water to form a slurry; transferring the slurry to a sealed hydrothermal reactor and reacting it at 180°C–240°C for 12–24 h; naturally cooling it to room temperature; and repeatedly washing it to remove unreacted raw materials and byproducts; drying the washed product at 80°C–100°C for 5–10 h to obtain a dry powder, which is the electronic compound containing the pinned phase.

[0021] A method for manufacturing an electronic compound containing a pinned phase by single crystal pulling includes: uniformly mixing an electronic compound precursor with a transition metal oxide / transition metal nitride, placing the mixture in a crucible, heating it to a molten state in a high-temperature furnace, immersing the electronic compound crystal as a seed crystal into the molten mixture by a Czochralski method, and pulling it out at a constant preset speed, controlling the temperature gradient and crystal pulling speed to form an electronic compound containing a pinned phase;

[0022] A method for preparing an electronic compound containing a pinned phase by a sol-gel method includes: dissolving a precursor of the electronic compound and a precursor of a transition metal oxide / transition metal nitride in a suitable solvent to form a homogeneous sol; then gradually transforming the sol into a gel by controlling the hydrolysis and condensation reactions of the sol; and then drying and calcining the gel to remove organic components and solvents to form an electronic compound containing a pinned phase.

[0023] A method for preparing an electronic compound containing a pinned phase by combustion synthesis includes: mixing an electronic compound precursor with a transition metal oxide / transition metal nitride precursor in a certain proportion, adding fuel, and igniting at a high temperature to form an electronic compound containing a pinned phase.

[0024] A method for preparing an electronic compound containing a pinned phase by coprecipitation includes: dissolving an electronic compound precursor and a transition metal oxide / transition metal nitride precursor in water to form a homogeneous solution; adding a precipitant dropwise to simultaneously precipitate the metal contained in the electronic compound and the hydroxide of the transition metal to form a coprecipitate; filtering, washing, drying, and calcining the coprecipitate at high temperature to remove moisture and organic impurities, thereby forming an electronic compound containing a pinned phase.

[0025] As a further improvement of the present invention, in step 2, the transition metal is loaded onto the carrier by impregnation, physical mixing, thermal decomposition, vapor deposition or atomic layer deposition.

[0026] As a further improvement of the present invention, in step 3, the carrier loaded with transition metal is reduced by a gas containing hydrogen.

[0027] This invention also discloses an ammonia synthesis method based on the above-mentioned ammonia synthesis catalyst, comprising:

[0028] In the ammonia synthesis reactor, under reaction temperatures of 50℃ to 500℃ and reaction pressures of 10kPa to 10MPa, the raw materials hydrogen and nitrogen are continuously reacted on the ammonia synthesis catalyst.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] The metal-supported catalyst of this invention exhibits a stronger anchoring effect with the support through strong metallic bonds formed between the active metal and the pinned phase, and through lattice matching formed by the close lattice constants between the active metal and the pinned phase. Therefore, it can stably produce ammonia over a long period. Furthermore, due to the low electron work function of the electron-supported compound, it has a stronger electron transfer capacity compared to traditional catalyst supports such as carbon supports and metal oxide supports. Thus, the metal-supported catalyst of this invention exhibits high ammonia synthesis activity even under low reaction temperature and low reaction pressure conditions, and possesses excellent durability, making it particularly suitable as a catalyst for ammonia synthesis. Attached Figure Description

[0031] Figure 1 This is a flowchart of the preparation method of the ammonia synthesis catalyst disclosed in this invention.

[0032] Figure 2 The graphs show the catalyst ammonia synthesis activity test results of Examples 1-3 and Comparative Example 1 of this invention;

[0033] Figure 3 These are catalyst lifetime test diagrams for Examples 1-3 and Comparative Example 1 of the present invention. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] The present invention will now be described in further detail with reference to the accompanying drawings:

[0036] Adding transition metal oxides or nitrides as pinning phases to electronic compounds is an effective solution. On one hand, it enhances the corrosion resistance of the electronic compounds, preventing degradation in harsh environments. On the other hand, the pinning phase can form strong metallic bonds with the metal, and the lattice constants of the pinning phase and the active metal are relatively close on certain crystal planes, resulting in good lattice matching. This helps reduce interfacial energy, improves interfacial stability, and enhances the anchoring effect of the metal on the support surface, effectively preventing metal agglomeration and exfoliation. Furthermore, the pinning phase provides more active sites, promoting the reaction and improving the overall performance and lifetime of the catalyst, leading to superior performance in industrial applications. As found in the paper "Metal-support interactions in designing noble metal-based catalysts for advanced catalysis," regulating the interaction between the metal and the oxide support can significantly improve catalyst performance and extend its lifetime. The paper “Structurally disordered RuO2 nanosheets with rich oxygen vacancies for enhanced nitrate electroreduction to ammonia” found that RuO2 has excellent selectivity (96.42%) and Faraday efficiency (97.46%) in ammonia synthesis, thus achieving the best ammonia synthesis performance.

[0037] This invention provides an ammonia synthesis catalyst, which is a metal-supported catalyst comprising a support and an active metal supported on the support; the support is an electron compound containing a pinned phase, wherein the pinned phase is a transition metal oxide or a transition metal nitride; the active metal is a transition metal, preferably an elemental transition metal.

[0038] The electron compound is C 12One or a combination of A7, Y5Si3, LaScSi, LaRuSi, LaNiSi, LaCoSi, LiH, La3AlN, Ba-Ca(NH2)2, CaFH, Ca2N, Sr2N, Y2C, C5A3, C3A, Gd2C, Tb2C, Dy2C, Ho2C, and Er2C, wherein the transition metal involved in the pinned phase and the active metal includes at least one of Ru, Co, Ni, Fe, and Mo; furthermore, the pinned phase and the active metal are preferably the same transition metal.

[0039] In the carrier, the content of the pinned phase is 0.01 wt% to 2 wt%; and the loading of the active metal relative to the carrier is 0.01 wt% to 50 wt%.

[0040] like Figure 1 As shown, the present invention provides a method for preparing an ammonia synthesis catalyst, comprising:

[0041] Step 1: Prepare an electron-containing compound containing a pinned phase by hydrothermal synthesis, single crystal pulling, sol-gel method, combustion synthesis or coprecipitation method to obtain a carrier;

[0042] Specifically:

[0043] A method for manufacturing an electronic compound containing a pinned phase via a hydrothermal process includes: mixing a precursor of the electronic compound with a transition metal oxide / transition metal nitride and water to form a slurry; transferring the slurry to a sealed hydrothermal reactor and reacting it at 180°C–240°C for 12–24 h; naturally cooling it to room temperature; and repeatedly washing it to remove unreacted raw materials and byproducts; drying the washed product at 80°C–100°C for 5–10 h to obtain a dry powder, which is the electronic compound containing the pinned phase.

[0044] A method for manufacturing an electronic compound containing a pinned phase by single crystal pulling includes: uniformly mixing an electronic compound precursor with a transition metal oxide / transition metal nitride, placing the mixture in a crucible, heating it to a molten state in a high-temperature furnace, immersing the electronic compound crystal as a seed crystal into the molten mixture by a Czochralski method, and pulling it out at a constant preset speed, controlling the temperature gradient and crystal pulling speed to form an electronic compound containing a pinned phase;

[0045] A method for preparing an electronic compound containing a pinned phase by a sol-gel method includes: dissolving a precursor of the electronic compound and a precursor of a transition metal oxide / transition metal nitride in a suitable solvent to form a homogeneous sol; then gradually transforming the sol into a gel by controlling the hydrolysis and condensation reactions of the sol; and then drying and calcining the gel to remove organic components and solvents to form an electronic compound containing a pinned phase.

[0046] A method for preparing an electronic compound containing a pinned phase by combustion synthesis includes: mixing an electronic compound precursor with a transition metal oxide / transition metal nitride precursor in a certain proportion, adding fuel, and igniting at a high temperature to form an electronic compound containing a pinned phase.

[0047] A method for preparing an electronic compound containing a pinned phase by coprecipitation includes: dissolving an electronic compound precursor and a transition metal oxide / transition metal nitride precursor in water to form a homogeneous solution; adding a precipitant dropwise to simultaneously precipitate the metal contained in the electronic compound and the hydroxide of the transition metal to form a coprecipitate; filtering, washing, drying, and calcining the coprecipitate at high temperature to remove moisture and organic impurities, thereby forming an electronic compound containing a pinned phase.

[0048] Step 2: Load the transition metal onto the carrier using methods such as impregnation, physical mixing, thermal decomposition, vapor deposition, or atomic layer deposition.

[0049] Step 3: The support loaded with transition metal is reduced by a gas containing hydrogen to obtain a metal-supported catalyst, which is used as an ammonia synthesis catalyst.

[0050] This invention provides an ammonia synthesis method based on an ammonia synthesis catalyst, comprising:

[0051] In the ammonia synthesis reactor, under reaction temperatures of 50℃ to 500℃ and reaction pressures of 10kPa to 10MPa, the raw materials hydrogen and nitrogen are continuously reacted on the ammonia synthesis catalyst.

[0052] Example 1:

[0053] An ammonia synthesis catalyst comprising: Ru / C 12 A7-RuO2.

[0054] The preparation method of the above-mentioned ammonia synthesis catalyst includes: weighing Al(OH)3, CaCO3, and RuO2, such that the molar ratio of Al to Ca is 12:7 and the specific gravity of RuO2 is 0.02wt%, mixing these raw materials with water to form a slurry, and then transferring it to a sealed hydrothermal reactor for reaction at 200℃ for 13 hours. After the reaction, the reactor is naturally cooled to room temperature, the product is removed, and washed repeatedly with deionized water. The product is dried at 80℃ for 5 hours to obtain a dry powder. Ru catalyst is then loaded onto the surface using an impregnation method; the Ru loading is 10wt%. Finally, the support loaded with the transition metal is reduced by a gas containing hydrogen.

[0055] The ammonia synthesis method based on the above-mentioned ammonia synthesis catalyst includes: in an ammonia synthesis reactor, under the conditions of a reaction temperature of 350°C and a reaction pressure of 1 MPa, continuously reacting the raw materials hydrogen and nitrogen on the ammonia synthesis catalyst.

[0056] Example 2:

[0057] An ammonia synthesis catalyst comprising: Ru / C 12 A7-RuO2.

[0058] The preparation method of the above-mentioned ammonia synthesis catalyst includes: using CaCO3, Al2O3 and RuO2 as raw materials, mixing them, sintering them in a high-temperature furnace at 800°C for 2 hours, then raising the temperature to 1200°C and holding for 5 hours to obtain C. 12 A7 polycrystalline, with RuO2 added at 1.2 wt%. C 12 A7 polycrystalline material was placed in a crucible and heated to 1340℃, held at that temperature for 1 hour to ensure uniform mixing. The C4 polycrystalline material was then mixed using the Czochralski method. 12 A7 seed crystal is immersed in the melt and slowly pulled out at a constant speed to form C containing RuO2 pinned phase. 12 A7 single crystal. The single crystal was pulverized into nanoparticles using an air jet mill, and then deposited onto C64 using a vapor deposition method. 12 A7-RuO2 supports a Ru catalyst with a Ru loading of 9 wt%; finally, the support containing the transition metal is reduced by a gas containing hydrogen.

[0059] The ammonia synthesis method based on the above-mentioned ammonia synthesis catalyst includes: continuously reacting raw material hydrogen and nitrogen on the ammonia synthesis catalyst in an ammonia synthesis reactor at a reaction temperature of 400°C and a reaction pressure of 1.3 MPa.

[0060] Example 3:

[0061] An ammonia synthesis catalyst comprising: Co / Ca2N-CoO.

[0062] The preparation method of the above-mentioned ammonia synthesis catalyst includes: dissolving calcium nitrate and cobalt nitrate in deionized water to form a homogeneous solution; adding citric acid to the calcium-cobalt solution and stirring until homogeneous to form a sol; heating the sol to 60°C and stirring at a constant temperature until the sol gradually becomes a transparent and homogeneous gel; drying the gel at 80°C for 12 hours, then placing it in a muffle furnace and maintaining it at 900°C for 4 hours, followed by natural cooling to room temperature to obtain a Ca2N-CoO support with a CoO content of 0.05 wt%; loading a Co catalyst onto the Ca2N-CoO surface using atomic layer deposition with a Co loading of 25 wt%; and finally, reducing the support loaded with transition metals using a hydrogen-containing gas.

[0063] The ammonia synthesis method based on the above-mentioned ammonia synthesis catalyst includes: in an ammonia synthesis reactor, under the conditions of a reaction temperature of 300°C and a reaction pressure of 1 MPa, continuously reacting the raw materials hydrogen and nitrogen on the ammonia synthesis catalyst.

[0064] Comparative example:

[0065] An ammonia synthesis catalyst comprising: Ru / C 12 A7.

[0066] The preparation method of the above-mentioned ammonia synthesis catalyst includes: weighing Al(OH)3 and CaCO3 to achieve a molar ratio of Al to Ca of 12:7; mixing these raw materials with water to form a slurry; then transferring the slurry to a sealed hydrothermal reactor and reacting at 200°C for 13 hours. After the reaction, the reactor is naturally cooled to room temperature, the product is removed, and washed repeatedly with deionized water. The product is dried at 80°C for 5 hours to obtain a dry powder. Ru catalyst is then loaded onto the surface using an impregnation method, with a Ru loading of 10 wt%.

[0067] The ammonia synthesis method based on the above-mentioned ammonia synthesis catalyst includes: in an ammonia synthesis reactor, under the conditions of a reaction temperature of 350°C and a reaction pressure of 1 MPa, continuously reacting the raw materials hydrogen and nitrogen on the ammonia synthesis catalyst.

[0068] test:

[0069] The catalyst ammonia synthesis activity test results of Examples 1-3 and the comparative examples are as follows: Figure 2 As shown.

[0070] The lifetime test results of ammonia synthesis catalysts in Examples 1-3 and the comparative examples are as follows: Figure 3 As shown.

[0071] result:

[0072] Lifetime tests were performed on catalysts in different embodiments, revealing that catalysts containing the pinned phase had longer lifetimes. For example... Figure 2 As shown, Ru / C 12 The ammonia synthesis rate of A7-RuO2 (hydrothermal method) is 0.9 mmol / g / h, with a continuous ammonia synthesis time of 350 hours. The Ru / C ratio is... 12 The ammonia synthesis rate of A7-RuO2 (single crystallization method) was 1.1 mmol / g / h, with a continuous ammonia synthesis time of 400 hours. The ammonia synthesis rate of Co / Ca2N-CoO was 0.5 mmol / g / h, with a continuous ammonia synthesis time of 300 hours. (Comparative example: Ru / C...) 12 The ammonia synthesis rate of A7 is 0.7 mmol / g / h, with a continuous ammonia synthesis time of 200 hours. For example... Figure 3As shown, catalysts containing pinned phases exhibit significant improvements in both ammonia synthesis rate and catalyst lifetime.

[0073] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An ammonia synthesis catalyst, characterized in that, The ammonia synthesis catalyst is a metal-supported catalyst, which includes a support and an active metal supported on the support; The carrier is an electronic compound containing a pinned phase, wherein the pinned phase is a transition metal oxide or a transition metal nitride; The active metal is a transition metal; The transition metals involved in the pinned phase and the active metal include at least one of Ru, Co, Ni, Fe, and Mo, and the transition metals used in the pinned phase and the active metal are the same. In the carrier, the content of the pinning phase is 0.01wt%~2wt%; The electron compound is C. 12 One or a combination of A7, Y5Si3, LaScSi, LaRuSi, LaNiSi, LaCoSi, Ca2N, Sr2N, Y2C, C5A3, C3A, Gd2C, Tb2C, Dy2C, Ho2C, and Er2C.

2. The ammonia synthesis catalyst according to claim 1, characterized in that, The loading of the active metal relative to the carrier is 0.01wt% to 50wt%.

3. A method for preparing an ammonia synthesis catalyst as described in any one of claims 1 to 2, characterized in that, include: Step 1: Prepare an electron compound containing a pinned phase to obtain a carrier; Step 2: Load the transition metal onto the carrier; Step 3: Reduce the carrier loaded with transition metal.

4. The method for preparing the ammonia synthesis catalyst according to claim 3, characterized in that, In step 1, an electronic compound containing a pinned phase is prepared by hydrothermal synthesis, single crystal pulling, sol-gel method, combustion synthesis or coprecipitation method.

5. The method for preparing the ammonia synthesis catalyst according to claim 4, characterized in that, A method for preparing an electronic compound containing a pinned phase by hydrothermal synthesis includes: mixing a precursor of the electronic compound with a transition metal oxide or transition metal nitride and water to form a slurry; transferring the slurry to a sealed hydrothermal reactor and reacting it at 180°C to 240°C for 12 to 24 hours; naturally cooling it to room temperature; and repeatedly washing it to remove unreacted raw materials and byproducts; drying the washed product at 80°C to 100°C for 5 to 10 hours to obtain a dry powder, which is the electronic compound containing the pinned phase. or, A method for manufacturing an electronic compound containing a pinned phase by single crystal pulling includes: uniformly mixing an electronic compound precursor with a transition metal oxide or a transition metal nitride, placing the mixture in a crucible, heating it to a molten state in a high-temperature furnace, immersing the electronic compound crystal as a seed crystal into the molten mixture by a Czochralski method, and pulling it out at a constant preset speed, controlling the temperature gradient and crystal pulling speed to form an electronic compound containing a pinned phase; or, A method for preparing an electronic compound containing a pinned phase by means of a sol-gel method includes: dissolving a precursor of the electronic compound and a precursor of a transition metal oxide or a transition metal nitride in a solvent to form a homogeneous sol; then gradually transforming the sol into a gel by controlling the hydrolysis and condensation reactions of the sol; and then drying and calcining the gel to remove organic components and solvent to form an electronic compound containing a pinned phase. or, A method for preparing an electronic compound containing a pinned phase by combustion synthesis includes: mixing a precursor of the electronic compound with a precursor of a transition metal oxide or a transition metal nitride in a certain proportion, adding fuel and igniting at a high temperature to form an electronic compound containing a pinned phase. or, A method for preparing an electronic compound containing a pinned phase by coprecipitation includes: dissolving an electronic compound precursor and a transition metal oxide or transition metal nitride precursor in water to form a homogeneous solution; adding a precipitant dropwise to simultaneously precipitate the metal contained in the electronic compound and the hydroxide of the transition metal to form a coprecipitate; filtering, washing, drying, and calcining the coprecipitate at high temperature to remove moisture and organic impurities, thereby forming an electronic compound containing a pinned phase.

6. The method for preparing the ammonia synthesis catalyst according to claim 3, characterized in that, In step 2, the transition metal is loaded onto the carrier by impregnation, physical mixing, thermal decomposition, vapor deposition or atomic layer deposition. In step 3, the support loaded with transition metal is reduced by a gas containing hydrogen.

7. An ammonia synthesis method based on the ammonia synthesis catalyst according to any one of claims 1 to 2, characterized in that, include: In the ammonia synthesis reactor, under reaction temperatures of 50℃ to 500℃ and reaction pressures of 10kPa to 10MPa, the raw materials hydrogen and nitrogen are continuously reacted on the ammonia synthesis catalyst.

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