Supported ruthenium-containing alkali metal hydride, process for its preparation and ammonia synthesis catalyst
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- YONGJIANG LAB
- Filing Date
- 2023-12-05
- Publication Date
- 2026-06-23
Smart Images
Figure CN117960166B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of catalysis technology, and particularly relates to supported ruthenium-containing alkali metal hydrides, their preparation methods, and ammonia synthesis catalysts. Background Technology
[0002] Ammonia possesses advantages such as high energy density, large hydrogen storage capacity, easy liquefaction, mature production, storage, and transportation technologies, and no carbon-containing compounds produced during decomposition. It is an energy carrier with broad application prospects; for example, ammonia is a major raw material for nitrogen fertilizers and a nitrogen source for the artificial synthesis of almost all important nitrogen-containing chemicals. Ammonia synthesis is one of the world's largest chemical industries, with an annual output approaching 200 million tons.
[0003] Industrial ammonia synthesis mainly employs the Haber-Bosch process, which converts nitrogen into ammonia through the reaction N2 + 3H2 = 2NH3 under catalytic conditions. From a thermodynamic equilibrium perspective, low temperature and high pressure conditions are favorable for ammonia formation. However, due to the high kinetic resistance of the ammonia synthesis reaction, in actual industrial production, the reaction needs to be carried out under high temperature and high pressure conditions (400℃~500℃, 15MPa~30MPa) to achieve a high reaction rate and ammonia yield, resulting in very high energy consumption. This process consumes 1% to 2% of the global energy supply annually and emits approximately 450 million tons of CO2, accounting for 1.2% of global carbon emissions.
[0004] The key to reducing energy consumption and costs in ammonia synthesis lies in developing ammonia synthesis catalysts with high activity and stability under relatively mild reaction conditions. Over the past century of ammonia synthesis development, two generations of industrial-scale ammonia synthesis catalysts have emerged: iron-based and ruthenium-based. Iron-based catalysts offer the advantage of lower cost, but their reaction conditions are more demanding, requiring operation under high temperature and pressure, resulting in high energy consumption and significant pollutant emissions. In contrast, ruthenium-based ammonia synthesis catalysts offer advantages such as high activity, mild reaction conditions, low energy consumption, and insensitivity to water, carbon oxides, and ammonia concentrations, significantly reducing production costs. They are considered the ideal second-generation ammonia synthesis catalyst after iron-based catalysts. Currently, the KAAP process based on activated carbon-supported ruthenium ammonia synthesis catalysts, developed by BP and Kellogg, has been industrialized. However, most Ru-based catalysts still require medium to high temperature conditions (350℃~450℃) to exhibit high ammonia synthesis rates, and their activity under low temperature conditions still needs to be improved. In addition, the high price of metallic Ru leads to high catalyst costs, which is another major factor restricting its widespread application. Therefore, how to reduce the amount of precious metal Ru, improve Ru atom utilization, and reduce catalyst costs is one of the technical problems that need to be solved. Summary of the Invention
[0005] In view of the above-mentioned technological status, the present invention provides a supported ruthenium-containing alkali metal hydride that can be used as a catalyst for ammonia synthesis, which can balance low ruthenium content, low energy consumption and high activity.
[0006] The technical solution provided by this invention is: a supported ruthenium-containing alkali metal hydride, which is composed of a carrier, ruthenium particles and alkali metal hydride, wherein the ruthenium particles and alkali metal hydride are loaded on the carrier.
[0007] The alkali metal is not limited, but includes lithium, sodium, potassium, rubidium, cesium, etc.
[0008] The carrier is not limited and includes carbon materials (such as graphene, carbon nanotubes, nanodiamonds, etc.), two-dimensional materials (such as hexagonal boron nitride, g-C3N4, MXene, etc.), oxides (such as magnesium oxide, silicon oxide, rare earth oxides, etc.).
[0009] In the supported ruthenium-containing alkali metal hydride, preferably, the mass percentage of metallic ruthenium is 0.1% to 20%, more preferably 0.1% to 10%, and even more preferably 0.1% to 5%.
[0010] In the supported ruthenium-containing alkali metal hydride, preferably, the mass percentage of the alkali metal hydride is 0.1% to 50%, more preferably 1% to 30%, and even more preferably 5% to 30%.
[0011] This invention also provides a method for preparing a supported ruthenium-containing alkali metal hydride, comprising the following steps:
[0012] The support is mixed with a ruthenium precursor solution to load the ruthenium precursor onto the support, resulting in a precursor mixture. The precursor mixture is then mixed with an alkali metal to obtain a mixture. In a high-pressure reactor under a hydrogen atmosphere, the alkali metal is controlled to be in a molten state, and the alkali metal reacts with hydrogen to obtain a supported ruthenium-containing alkali metal hydride.
[0013] The ruthenium precursor is not limited, and includes one or more of the following: ruthenium chloride, ruthenium nitrite, ruthenium acetylacetone, potassium ruthenate, and ruthenium dodecylcarbonyl.
[0014] The reaction temperature needs to ensure that the alkali metal is in a molten state, that is, above the melting point of the alkali metal, preferably 50℃~500℃.
[0015] Preferably, the pressure during the reaction is 0.1 MPa to 10.0 MPa.
[0016] Preferably, the support is first calcined in argon gas and then mixed with the ruthenium precursor. More preferably, the calcination temperature is 200℃~1200℃ and the calcination time is 1~20h.
[0017] Preferably, the reaction time is 1 to 20 hours.
[0018] To further improve the dispersion of alkali metal hydrides, the reaction product was ground and then calcined in Ar at a temperature of 200℃ to 1200℃ for a time of 1h to 20h.
[0019] The supported ruthenium-containing alkali metal hydride of the present invention can be used as a catalyst for ammonia synthesis. That is, an ammonia synthesis catalyst includes the supported ruthenium-containing alkali metal hydride.
[0020] Preferably, in the ammonia synthesis reaction, the volume ratio of nitrogen to hydrogen, N2:H2, is 1:9 to 9:1.
[0021] Preferably, the total pressure in the ammonia synthesis reaction is 0.1 MPa to 30 MPa.
[0022] Preferably, the gas space velocity (GHSV) during ammonia synthesis is 1000–1000000 mL / g. cat -1 h -1 .
[0023] Preferably, the reaction temperature in the ammonia synthesis reaction is 100℃~600℃, more preferably 250℃~500℃, and even more preferably 300℃~400℃.
[0024] As a catalyst for ammonia synthesis, in order to balance low cost, low energy consumption and high activity, the reaction temperature is preferably 300℃~400℃, and the mass percentage of metallic ruthenium in the supported ruthenium-containing alkali metal hydride is preferably 0.1%~20%, more preferably 0.1%~10%, and even more preferably 0.1%~5%.
[0025] Compared with the prior art, the present invention has the following advantages:
[0026] (1) In this invention, ruthenium particles and alkali metal hydrides are simultaneously supported on the support. Both ruthenium metal and alkali metal hydrides have catalytic activity. Therefore, the obtained supported ruthenium-containing alkali metal hydrides have good catalytic activity.
[0027] (2) In this invention, the method for preparing supported ruthenium-containing alkali metal hydrides is simple and easy to implement. Alkali metal hydrides are obtained through alkali metal hydrogenation reactions. During the reaction, the alkali metal is in a molten state, which can effectively disperse it on the surface of the support, thereby improving the dispersion of the metal. Therefore, the obtained alkali metal hydrides have a uniform particle size distribution and are highly dispersed on the support, reaching sub-nanometer clusters or even single-atom levels.
[0028] (3) The supported ruthenium-containing alkali metal hydride of the present invention can be used as a catalyst for ammonia synthesis reaction. Due to the synergistic effect of alkali metal hydride and Ru, the catalytic activity of ammonia synthesis reaction can be effectively improved. Compared with single alkali metal hydride active component and single Ru active component, the catalytic activity of ammonia synthesis is greatly improved.
[0029] (4) When the supported ruthenium-containing alkali metal hydride of the present invention is used as a catalyst for ammonia synthesis, since Ru is highly dispersed in the catalyst, its active sites can be fully utilized. Therefore, under the condition of reducing the amount of precious metal Ru, the utilization rate of Ru atoms can be improved and the cost of catalyst can be reduced.
[0030] (5) When the supported ruthenium-containing alkali metal hydride of the present invention is used as a catalyst for ammonia synthesis, it exhibits significant catalytic activity at a low temperature of 200°C. When the reaction temperature is between 300°C and 400°C, it still has good catalytic activity at a low ruthenium content. Therefore, it can take into account low cost, low energy consumption and high activity. Attached Figure Description
[0031] Figure 1 These are the X-ray diffraction patterns of Ru-KH / C in Examples 1-3 and KH / C in Comparative Example 2 of the present invention.
[0032] Figure 2 These are the ammonia synthesis catalytic performance curves of Examples 1-3 and Comparative Examples 1-2 of the present invention. Detailed Implementation
[0033] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings. It should be noted that the embodiments described below are intended to facilitate the understanding of the present invention and do not limit it in any way.
[0034] Example 1:
[0035] 200 mg of graphene was weighed and calcined at 550 °C for 6 h in an Ar atmosphere to serve as a support. 0.42 mg of dodecyltriruthenium carbonyl was weighed and dissolved in 5 mL of acetone to obtain a dodecyltriruthenium carbonyl / acetone solution. This solution was added to the support to load the dodecyltriruthenium carbonyl onto it, yielding a precursor (Ru / C). 50 mg of metallic potassium was weighed and added to the precursor, mixed thoroughly. The mixture was reacted in a high-pressure reactor at 100 °C and 1.0 MPa in an H2 atmosphere for 10 h. The product was thoroughly ground in a mortar and then calcined at 400 °C for 2 h in an Ar atmosphere to obtain graphene-supported ruthenium-containing potassium hydride, with a ruthenium mass percentage of 0.1%, denoted as 0.1%Ru-KH / C.
[0036] The 0.1% Ru-KH / C catalyst was used for the ammonia synthesis reaction, with the chemical formula N2 + 3H2 = 2NH3. The 0.1% Ru-KH / C catalyst was tested in a fixed-bed ammonia synthesis catalytic performance evaluation system, as detailed below:
[0037] A fixed-bed reactor was used, in which 0.1% Ru-KH / C was dispersed in a fixed bed, and nitrogen and hydrogen gases were introduced at a ratio of N2:H2 = 1:3. The reaction temperature range was 200℃ to 400℃, the pressure was 1.0 MPa, and the gas hourly space velocity was 36000 mLg. cat -1 h -1 The concentration of ammonia in the product was quantitatively analyzed online using a conductivity meter.
[0038] Example 2:
[0039] 200 mg of graphene was weighed and calcined at 550 °C for 6 h in an Ar atmosphere to serve as a support. 3.37 mg of dodecylruthenium carbonyl was weighed and added to the support, dissolved in 5 mL of acetone to obtain a dodecylruthenium carbonyl / acetone solution. This solution was added to the support to load the dodecylruthenium carbonyl onto it, yielding a precursor (Ru / C). 50 mg of metallic potassium was weighed and added to the precursor, mixed thoroughly. The mixture was reacted in a high-pressure reactor at 100 °C and 1.0 MPa in an H2 atmosphere for 10 h. The product was thoroughly ground in a mortar and then calcined at 400 °C for 2 h in an Ar atmosphere to obtain graphene-supported ruthenium-containing potassium hydride, with a ruthenium mass percentage of 0.8%, denoted as 0.8%Ru-KH / C.
[0040] The 0.8% Ru-KH / C catalyst was used for the ammonia synthesis reaction, with the chemical formula N2 + 3H2 = 2NH3. The 0.8% Ru-KH / C catalyst was tested in a fixed-bed ammonia synthesis catalytic performance evaluation system, as detailed below:
[0041] A fixed-bed reactor was used, in which 0.8% Ru-KH / C was dispersed in a fixed bed, and nitrogen and hydrogen gases were introduced at a ratio of N2:H2 = 1:3. The reaction temperature range was 200℃ to 400℃, the pressure was 1.0 MPa, and the gas hourly space velocity was 36000 mLg. cat -1 h -1 The concentration of ammonia in the product was quantitatively analyzed online using a conductivity meter.
[0042] Example 3:
[0043] 200 mg of graphene was weighed and calcined at 550 °C for 6 h in an Ar atmosphere to serve as a support. 16.9 mg of dodecylruthenium carbonyl was weighed and added to the support, dissolved in 5 mL of acetone to obtain a dodecylruthenium carbonyl / acetone solution. This solution was added to the support to load the dodecylruthenium carbonyl onto it, yielding a precursor (Ru / C). 50 mg of metallic potassium was weighed and added to the precursor, mixed thoroughly. The mixture was reacted in a high-pressure reactor at 100 °C and 1.0 MPa in an H2 atmosphere for 10 h. The product was thoroughly ground in a mortar and then calcined at 400 °C for 2 h in an Ar atmosphere to obtain graphene-supported ruthenium-containing potassium hydride, with a ruthenium mass percentage of 4%, denoted as 4%Ru-KH / C.
[0044] The 4% Ru-KH / C catalyst was used in the ammonia synthesis reaction, with the chemical formula N2 + 3H2 = 2NH3. The 4% Ru-KH / C catalyst was tested in a fixed-bed ammonia synthesis catalytic performance evaluation system, as detailed below:
[0045] A fixed-bed reactor was used, in which 4% Ru-KH / C was dispersed in a fixed bed, and nitrogen and hydrogen were introduced at a ratio of N2:H2 = 1:3. The reaction temperature range was 200℃ to 400℃, the pressure was 1.0 MPa, and the gas hourly space velocity was 36000 mLg. cat -1 h -1 The concentration of ammonia in the product was quantitatively analyzed online using a conductivity meter.
[0046] Comparative Example 1:
[0047] 200 mg of graphene was weighed and calcined at 550 °C for 6 h in an Ar atmosphere to obtain a support. 3.37 mg of ruthenium dodecylcarbonyl was weighed and added to the support, dissolved in 5 mL of acetone to obtain a ruthenium dodecylcarbonyl / acetone solution. This solution was added to the support to load ruthenium dodecylcarbonyl, and then calcined at 400 °C for 2 h in an Ar atmosphere to obtain graphene-supported ruthenium, wherein the ruthenium mass percentage was 0.8%, denoted as 0.8% Ru / C.
[0048] The 0.8% Ru / C catalyst was used in the ammonia synthesis reaction, with the chemical formula N2 + 3H2 = 2NH3. The 0.8% Ru / C catalyst was tested in a fixed-bed ammonia synthesis catalytic performance evaluation system, as detailed below:
[0049] A fixed-bed reactor was used, with 0.8% Ru / C dispersed in a fixed bed. Nitrogen and hydrogen gases were introduced, with an N2:H2 ratio of 1:3. The reaction temperature range was 200℃ to 400℃, the pressure was 1.0 MPa, and the gas hourly space velocity (GHSV) was 36000 mLg. cat -1 h -1The concentration of ammonia in the product was quantitatively analyzed online using a conductivity meter.
[0050] Comparative Example 2:
[0051] 200 mg of graphene was weighed and calcined at 550 °C for 6 h in an Ar atmosphere to obtain a support. 50 mg of metallic potassium was weighed and added to the support, and mixed thoroughly. In a high-pressure reactor, the mixture was hydrogenated at H2, 100 °C, and 1.0 MPa for 10 h. The hydrogenated product was thoroughly ground in a mortar and then calcined at 400 °C for 2 h in an Ar atmosphere to obtain graphene-supported potassium hydride, denoted as KH / C.
[0052] The KH / C catalyst was used in the ammonia synthesis reaction, with the chemical formula N2 + 3H2 = 2NH3. The KH / C catalyst was tested in a fixed-bed ammonia synthesis catalytic performance evaluation system, as detailed below:
[0053] A fixed-bed reactor was used, in which KH / C was dispersed in a fixed bed, and nitrogen and hydrogen were introduced at a ratio of N2:H2 = 1:3. The reaction temperature range was 200℃ to 400℃, the pressure was 1.0 MPa, and the gas hourly space velocity was 36000 mLg. cat -1 h -1 The concentration of ammonia in the product was quantitatively analyzed online using a conductivity meter.
[0054] In Examples 1-7, the ruthenium particles and alkali metal hydrides in the supported ruthenium-containing alkali metal hydrides are loaded on a support, and the alkali metal hydrides have a uniform particle size distribution and are highly dispersed on the support. For example, the X-ray diffraction patterns of 0.1% Ru-KH / C in Example 1, 0.8% Ru-KH / C in Example 2, 4% Ru-KH / C in Example 3, and KH / C in Comparative Example 2 are shown below. Figure 1 As shown, it can be seen that KH in Ru-KH / C forms KH with the graphene support. 0.35 C 24 In the compound, Ru is supported on a support. Due to the high dispersion and small particle size of Ru on the support, no obvious diffraction peaks related to Ru can be observed in XRD.
[0055] The ammonia synthesis catalytic performance curves of Examples 1-3 and Comparative Examples 1-2 are as follows: Figure 2 As shown, it can be seen that:
[0056] (1) The catalytic activity of 0.8% Ru-KH / C in Example 2 was compared with that in Comparative Example 1. At the same temperature, the catalytic activity of 0.8% Ru-KH / C in Example 2 was much higher than that of 0.8% Ru / C in Comparative Example 1. For example, at 400°C, the catalytic activity of 0.8% Ru-KH / C in Example 2 was 33670 μmol / g. cat The catalytic activity of 0.8% Ru / C in Comparative Example 1 was only 171 μmol / g, while the catalytic activity of 0.8% Ru / C was only 171 μmol / g. cat The result shows that the catalytic activity increased by more than two orders of magnitude after the addition of KH, indicating that the addition of KH has a very significant effect on improving catalytic activity.
[0057] (2) Compared with KH / C in Comparative Example 2, the catalytic activity of 0.1% Ru-KH / C in Example 1, 0.8% Ru-KH / C in Example 2, and 4% Ru-KH / C in Example 3 were all improved. In particular, the catalytic activity of 0.8% Ru-KH / C in Example 2 and 4% Ru-KH / C in Example 3 was significantly improved, indicating that the addition of Ru also has a significant effect on improving the activity of the catalyst.
[0058] (3) Comparing 0.1% Ru-KH / C in Example 1, 0.8% Ru-KH / C in Example 2, and 4% Ru-KH / C in Example 3, it was found that the catalytic activity of Ru-KH / C increased with the increase of Ru content, indicating that Ru is also one of the active components of the catalyst.
[0059] (4) For 0.1% Ru-KH / C in Example 1, 0.8% Ru-KH / C in Example 2, and 4% Ru-KH / C in Example 3, the catalytic activity gradually increases above 300℃, especially at 350℃-400℃, where it exhibits good catalytic activity.
[0060] Example 4:
[0061] 200 mg of graphene was weighed and calcined at 550 °C for 6 h in an Ar atmosphere to serve as a support. 4.2 mg of dodecyltriruthenium carbonyl was weighed and dissolved in 5 mL of acetone to obtain a dodecyltriruthenium carbonyl / acetone solution. This solution was added to the support to load the dodecyltriruthenium carbonyl onto it, yielding a precursor (Ru / C). 50 mg of lithium metal was weighed and added to the precursor, mixed thoroughly. The mixture was reacted in a high-pressure reactor at 200 °C and 1.0 MPa in an H2 atmosphere for 10 h. The product was thoroughly ground in a mortar and then calcined at 400 °C for 2 h in an Ar atmosphere to obtain graphene-supported ruthenium-containing lithium hydride, wherein the ruthenium mass percentage was 1%, denoted as 1%Ru-LiH / C.
[0062] In this 1% Ru-LiH / C catalyst, Ru particles and LiH are supported on graphene, and the LiH particles have a uniform size distribution and are highly dispersed on the graphene. This 0.1% Ru-KH / C catalyst exhibits good catalytic activity when used as a catalyst for ammonia synthesis. Specific application methods are as follows:
[0063] A fixed-bed reactor was used, in which 0.1% Ru-LiH / C was dispersed in a fixed bed, and nitrogen and hydrogen gases were introduced at a ratio of N2:H2 = 1:3. The reaction temperature range was 200℃ to 400℃, the pressure was 1.0 MPa, and the gas hourly space velocity was 36000 mLg. cat -1 h -1 The concentration of ammonia in the product was quantitatively analyzed online using a conductivity meter.
[0064] Example 5:
[0065] 200 mg of graphene was weighed and calcined at 550 °C for 6 h in an Ar atmosphere to serve as a support. 4.2 mg of dodecyltriruthenium carbonyl was weighed and dissolved in 5 mL of acetone to obtain a dodecyltriruthenium carbonyl / acetone solution. This solution was added to the support to load the dodecyltriruthenium carbonyl onto it, yielding a precursor (Ru / C). 50 mg of metallic sodium was weighed and added to the precursor, mixed thoroughly. The mixture was reacted in a high-pressure reactor at 150 °C and 1.0 MPa in an H2 atmosphere for 10 h. The product was thoroughly ground in a mortar and then calcined at 400 °C for 2 h in an Ar atmosphere to obtain graphene-supported sodium ruthenium hydride, wherein the ruthenium mass percentage was 1%, denoted as 1%Ru-NaH / C.
[0066] In this 0.1% Ru-KH / C catalyst, Ru particles and KH are supported on graphene, and the KH particles have a uniform size distribution and are highly dispersed on the graphene. This 0.1% Ru-KH / C catalyst exhibits good catalytic activity when used as a catalyst for ammonia synthesis. Specific application methods are as follows:
[0067] A fixed-bed reactor was used, in which 0.1% Ru-KH / C was dispersed in a fixed bed, and nitrogen and hydrogen gases were introduced at a ratio of N2:H2 = 1:3. The reaction temperature range was 200℃ to 400℃, the pressure was 1.0 MPa, and the gas hourly space velocity was 36000 mLg. cat -1 h -1 The concentration of ammonia in the product was quantitatively analyzed online using a conductivity meter.
[0068] Example 6:
[0069] 200 mg of graphene was weighed and calcined at 550 °C for 6 h in an Ar atmosphere to serve as a support. 4.2 mg of dodecyltriruthenium carbonyl was weighed and dissolved in 5 mL of acetone to obtain a dodecyltriruthenium carbonyl / acetone solution. This solution was added to the support to load the dodecyltriruthenium carbonyl onto it, yielding a precursor (Ru / C). 50 mg of metallic rubidium was weighed and added to the precursor, mixed thoroughly. The mixture was reacted in a high-pressure reactor at H2, 100 °C, and 1.0 MPa for 10 h. The reaction product was thoroughly ground in a mortar and then calcined at 400 °C for 2 h in an Ar atmosphere to obtain graphene-supported rubidium hydride containing ruthenium, with a ruthenium mass percentage of 1%, denoted as 1%Ru-RbH / C.
[0070] In this 0.1% Ru-RbH / C catalyst, Ru particles and RbH are supported on graphene, and the RbH particles have a uniform size distribution and are highly dispersed on the graphene. This 0.1% Ru-RbH / C catalyst exhibits good catalytic activity when used as a catalyst for ammonia synthesis. Specific application methods are as follows:
[0071] A fixed-bed reactor was used, in which 0.1% Ru-RbH / C was dispersed in a fixed bed, and nitrogen and hydrogen gases were introduced at a ratio of N2:H2 = 1:3. The reaction temperature range was 200℃ to 400℃, the pressure was 1.0 MPa, and the gas hourly space velocity was 36000 mLg. cat -1 h -1 The concentration of ammonia in the product was quantitatively analyzed online using a conductivity meter.
[0072] Example 7:
[0073] 200 mg of graphene was weighed and calcined at 550 °C for 6 h in an Ar atmosphere to serve as a support. 4.2 mg of dodecyltriruthenium carbonyl was weighed and dissolved in 5 mL of acetone to obtain a dodecyltriruthenium carbonyl / acetone solution. This solution was added to the support to load the dodecyltriruthenium carbonyl onto it, yielding a precursor (Ru / C). 50 mg of metallic cesium was weighed and added to the precursor, mixed thoroughly. The mixture was reacted in a high-pressure reactor at H2, 100 °C, and 1.0 MPa for 10 h. The reaction product was thoroughly ground in a mortar and then calcined at 400 °C for 2 h in an Ar atmosphere to obtain graphene-supported cesium hydride containing ruthenium, with a ruthenium mass percentage of 1%, denoted as 1%Ru-CsH / C.
[0074] In this 1% Ru-CsH / C catalyst, Ru particles and CsH are supported on graphene, and the CsH particles have a uniform size distribution and are highly dispersed on the graphene. This 1% Ru-CsH / C catalyst exhibits good catalytic activity when used as a catalyst for ammonia synthesis. Specific application methods are as follows:
[0075] A fixed-bed reactor was used, in which 1% Ru-CsH / C was dispersed in a fixed bed, and nitrogen and hydrogen were introduced at a ratio of N2:H2 = 1:3. The reaction temperature range was 200℃ to 400℃, the pressure was 1.0 MPa, and the gas hourly space velocity was 36000 mLg. cat -1 h -1 The concentration of ammonia in the product was quantitatively analyzed online using a conductivity meter.
[0076] The embodiments described above provide a detailed explanation of the technical solution of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, additions, or similar substitutions made within the scope of the principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing supported ruthenium-containing alkali metal hydrides, characterized by: The supported ruthenium-containing alkali metal hydride consists of a support, ruthenium particles, and an alkali metal hydride, with the ruthenium particles and the alkali metal hydride loaded on the support. The preparation method of the supported ruthenium-containing alkali metal hydride includes the following steps: The support is mixed with a ruthenium precursor solution to load the ruthenium precursor onto the support, resulting in a support-loaded ruthenium precursor mixture. The precursor mixture is then mixed with an alkali metal to obtain a mixture. In a high-pressure reactor under a hydrogen atmosphere, the alkali metal is controlled to be in a molten state, and the alkali metal reacts with hydrogen to obtain a supported ruthenium-containing alkali metal hydride.
2. The method for preparing supported ruthenium-containing alkali metal hydrides as described in claim 1, characterized in that: The mass percentage of metallic ruthenium is 0.1% to 20%.
3. The method for preparing supported ruthenium-containing alkali metal hydrides as described in claim 2, characterized in that: The mass percentage of metallic ruthenium is 0.1% to 10%.
4. The method for preparing supported ruthenium-containing alkali metal hydrides as described in claim 3, characterized in that: The mass percentage of metallic ruthenium is 0.1% to 5%.
5. The method for preparing supported ruthenium-containing alkali metal hydrides as described in claim 1, characterized in that: The mass percentage of alkali metal hydrides is 0.1% to 50%.
6. The method for preparing supported ruthenium-containing alkali metal hydrides as described in claim 5, characterized in that: The mass percentage of alkali metal hydrides is 1% to 30%.
7. The method for preparing supported ruthenium-containing alkali metal hydrides as described in claim 6, characterized in that: The mass percentage of alkali metal hydrides is 5% to 30%.
8. The method for preparing supported ruthenium-containing alkali metal hydrides as described in claim 1, characterized in that: The alkali metals include one or more of lithium, sodium, potassium, rubidium, and cesium.
9. The method for preparing supported ruthenium-containing alkali metal hydrides as described in claim 1, characterized in that: The carrier includes one or more of carbon materials, two-dimensional materials, and oxides.
10. The method for preparing supported ruthenium-containing alkali metal hydrides as described in claim 9, characterized in that: The carbon material includes one or more of graphene, carbon nanotubes, and nanodiamonds.
11. The method for preparing supported ruthenium-containing alkali metal hydrides as described in claim 9, characterized in that: The two-dimensional material includes one or more of hexagonal boron nitride, g-C3N4, and MXene.
12. The method for preparing supported ruthenium-containing alkali metal hydrides as described in claim 9, characterized in that: The oxides include one or more of magnesium oxide, silicon oxide, and rare earth oxides.
13. The method for preparing supported ruthenium-containing alkali metal hydrides as described in claim 1, characterized in that: The ruthenium precursor includes one or more of ruthenium chloride, ruthenium nitrite, ruthenium acetylacetone, potassium ruthenate, and dodecacarbonyltriruthenium.
14. The method for preparing supported ruthenium-containing alkali metal hydrides as described in claim 1, characterized in that: First, the carrier is calcined in argon gas.
15. The method for preparing supported ruthenium-containing alkali metal hydrides as described in claim 14, characterized in that: The roasting temperature is 200°C to 1200°C.
16. The method for preparing supported ruthenium-containing alkali metal hydrides as described in claim 14, characterized in that: The roasting time is 1 hour to 20 hours.
17. The preparation method according to claim 1, characterized in that: The reaction temperature is controlled at 50°C to 200°C, and the pressure is controlled at 0.1 MPa to 10.0 MPa.
18. The method for preparing supported ruthenium-containing alkali metal hydrides as described in claim 1, characterized in that: The reaction time is 1 hour to 20 hours.
19. The method for preparing supported ruthenium-containing alkali metal hydrides as described in claim 1, characterized in that: The reaction product was ground and then calcined in an argon atmosphere.
20. The method for preparing supported ruthenium-containing alkali metal hydrides as described in claim 19, characterized in that: The roasting temperature is 200°C to 400°C.
21. The method for preparing supported ruthenium-containing alkali metal hydrides as described in claim 19, characterized in that: The roasting time is 1 hour to 20 hours.
22. Ammonia synthesis catalyst, characterized by: This includes supported ruthenium-containing alkali metal hydrides prepared by the method for preparing supported ruthenium-containing alkali metal hydrides according to any one of claims 19 to 21.
23. The ammonia synthesis catalyst as described in claim 22, characterized in that: In the ammonia synthesis reaction, the volume ratio of nitrogen to hydrogen is N2:H2 = 1:9~9:
1.
24. The ammonia synthesis catalyst according to claim 22, characterized in that: In the ammonia synthesis reaction, the total pressure is 0.1 MPa to 30 MPa.
25. The ammonia synthesis catalyst as described in claim 22, characterized in that: During ammonia synthesis, the gas hourly space velocity (GHSV) is 1000 mL / g. cat -1 h -1 ~1,000,000 mLg cat -1 h -1 .
26. The ammonia synthesis catalyst according to claim 22, characterized in that: In the ammonia synthesis reaction, the reaction temperature is 100°C to 600°C.
27. The ammonia synthesis catalyst according to claim 26, characterized in that: The reaction temperature is 200°C to 500°C.
28. The ammonia synthesis catalyst as described in claim 27, characterized in that: The reaction temperature is 300°C~400°C.
29. The ammonia synthesis catalyst according to claim 22, characterized in that: The reaction temperature is 300°C to 400°C, and the mass percentage of metallic ruthenium in the supported ruthenium-containing alkali metal hydride is 0.1% to 20%.
30. The ammonia synthesis catalyst as described in claim 29, characterized in that: The supported ruthenium-containing alkali metal hydride contains 0.1% to 10% ruthenium by mass.
31. The ammonia synthesis catalyst according to claim 30, characterized in that: The supported ruthenium-containing alkali metal hydride contains 0.1% to 5% ruthenium by mass.