Ammonia gas synthesis method based on osmium-platinum catalyst and nitrogen oxide

Abstract

The invention provides an ammonia gas synthesis method based on an osmium-platinum catalyst and nitrogen oxide, and solves the technical problem of high production cost caused by high price of a catalyst used for hydrogen reduction of nitrogen oxide in the prior art. The method comprises the following steps: respectively preparing NO, H2 and inert gas according to preset requirements; weighing an osmium-platinum catalyst, and adding the osmium-platinum catalyst into the tubular reactor containing the quartz wool; h2 is introduced into the tubular reactor, the reactor is heated to 200-400 DEG C, the osmium-platinum catalyst is pretreated at the temperature, and then the osmium-platinum catalyst continues to be cooled to the room temperature under purging of H2; meanwhile, NO, H2 and inert gas are introduced into the reactor to form mixed gas, the temperature in the tubular reactor is raised to a preset temperature, then heat preservation is conducted, the mixed gas reacts under the action of the osmium-platinum catalyst, and then ammonia gas can be synthesized. The method has lower energy consumption and higher yield, and the used catalyst is lower in cost and better in performance.

Description

Technical Field

[0001] The present invention relates to nitrogen oxides (NO x ), specifically a method for converting nitrogen oxides into ammonia using an osmium platinum catalyst. Background Art

[0002] Ammonia (NH3), a basic chemical raw material widely used in agriculture and industry, maintains the sustainable development of nature and society under a stable nitrogen cycle system. Traditional ammonia synthesis typically uses the Haber-Bosch (HB) process, which directly synthesizes ammonia using nitrogen (N2) and hydrogen (H2) over an iron (Fe)-based catalyst. This method requires the dissociation of N2 into active nitrogen atoms (N*). However, the activation energy required to break the N≡N triple bond is very high, and the HB process must be operated under high temperature and high pressure conditions, resulting in high energy consumption and low yield. Therefore, how to achieve efficient ammonia synthesis under mild conditions has attracted widespread attention from researchers.

[0003] Nitrogen oxides (NO x ) is a common pollutant in the atmosphere. Its large-scale emission can cause environmental problems such as photochemical smog, PM2.5, and acid rain. Therefore, treating nitrogen oxides is beneficial to protecting the atmospheric environment. Based on this, researchers have found that the reduction of nitrogen oxides using H2 has high reactivity and the final product is free of secondary pollution. At the same time, the activation energy required for the dissociation of nitrogen oxides is lower than that of N2, which is expected to simultaneously meet the requirements of low energy consumption and high yield in the synthetic ammonia process, and achieve efficient and clean treatment of nitrogen oxides.

[0004] Existing technologies often use platinum (Pt) as a catalyst for the reduction of nitrogen oxides with hydrogen to achieve efficient ammonia synthesis. However, Pt's catalytic activity is limited, and the reaction consumes a high amount of energy. Furthermore, Pt is a precious metal, making it expensive, leading to high production costs. Summary of the Invention

[0005] The purpose of the present invention is to solve the technical problems that the catalytic activity of the existing catalyst used for H2 reduction of nitrogen oxides is generally poor and the high price leads to high production costs, and to provide a method for synthesizing ammonia based on an osmium platinum catalyst and nitrogen oxides.

[0006] To achieve the above objectives, the technical solutions provided by the present invention are:

[0007] A method for synthesizing ammonia based on an osmium platinum catalyst and nitrogen oxides, which is special in that it comprises the following steps:

[0008] Step 1: Prepare NO, H2, and an inert gas in preset amounts; the volume concentration ratio of the NO and H2 when flowing into the reactor at uniform flow rates is (0.25% to 5%): (2.5% to 50%), with the remainder being inert gas; the flow rates of the NO and H2 during the reaction are preset according to process requirements;

[0009] Step 2, weighing an osmium platinum catalyst and adding it to a tubular reactor containing quartz wool; defining the amount of the osmium platinum catalyst as m, in mg, and the preset flow rate of NO gas entering the reactor as v, in ccm, then the amount of the osmium platinum catalyst m = (0.5-2) v; the molar ratio of osmium element and platinum element in the osmium platinum catalyst is 0.05-0.75:0.25-0.95;

[0010] Step 3, introducing H2 into the tubular reactor and heating the tubular reactor to 200-400°C, pretreating the osmium platinum catalyst at this temperature to activate it, and then continuing to cool the osmium platinum catalyst to room temperature under H2 purge; the flow rate of the H2 introduced is 30% to 100% of the H2 flow rate during the reaction, and the H2 flow rate during the reaction has been predetermined according to the process requirements;

[0011] Step 4: Simultaneously, the NO, H2, and inert gas prepared in step 1 are introduced into the tubular reactor at a uniform flow rate to form a mixed gas, and the temperature in the tubular reactor is raised to 50-200°C and then kept warm, so that the mixed gas reacts for 30 minutes to 3 hours under the action of the osmium platinum catalyst, and NO is converted into ammonia and collected, thereby completing the ammonia synthesis based on the osmium platinum catalyst and nitrogen oxides.

[0012] Furthermore, in step 1, the volume concentration ratio of NO and H2 is 0.25%:2.5%.

[0013] Furthermore, in step 2, the molar ratio of osmium element to platinum element in the osmium platinum catalyst is 0.05-0.15:0.85-0.95.

[0014] Furthermore, in step 2, the molar ratio of osmium element to platinum element in the osmium platinum catalyst is 0.1:0.9.

[0015] Furthermore, in step 3, the flow rate of the H2 is 40 to 60 ccm; and the pretreatment time is 0.5 to 2 h.

[0016] Furthermore, in step 4, when NO, H2 and an inert gas are introduced into the tubular reactor to form a mixed gas, the flow rate of NO is 100 ccm and the flow rate of H2 is 100 ccm.

[0017] Furthermore, in step 2, the osmium platinum catalyst is prepared by the following method:

[0018] 2.1. Weigh the osmium compound and the platinum compound based on the predetermined ratio of osmium and platinum in the osmium-platinum catalyst and the total amount of osmium and platinum in the desired osmium-platinum catalyst;

[0019] 2.2. Add the osmium compound and the platinum compound into a container respectively, and then add a solvent until the osmium compound and the platinum compound are completely dissolved to obtain an osmium platinum precursor solution;

[0020] 2.3. Adding the catalyst support and the solvent to the osmium platinum precursor solution in sequence and stirring uniformly to obtain a mixed solution; the mass of the catalyst support is N times the total mass of the osmium element and the platinum element, where 0≤N≤99; the total mass concentration of the osmium element and the platinum element in the mixed solution is 20 mg / L to 10 g / L; the total mass of the osmium element and the platinum element is calculated by the total amount of the osmium element and the platinum element and the ratio of the predetermined amount of the substance;

[0021] 2.4. Adding a reducing agent to the mixed solution at a temperature ranging from room temperature to below the boiling point of the solvent, and carrying out a heat-insulating reaction, followed by cooling to room temperature to obtain a suspension; the amount of the reducing agent is 2 to 200 times the sum of the amounts of the osmium element and the platinum element;

[0022] 2.5. Centrifuge, wash and dry the suspension in sequence to obtain the osmium platinum catalyst.

[0023] Further, in step 2.1, the osmium compound is selected from one or more of potassium hexachloroosmate, osmium (III) chloride hydrate, ammonium chloroosmate, sodium hexachloroosmium (IV) dihydrate, triosmium dodecacarbonyl, bis(cyclopentadienyl)osmium, and potassium osmate dihydrate;

[0024] The platinum compound is selected from one or more of potassium chloroplatinate, chloroplatinic acid hydrate, platinum tetrachloride, sodium chloroplatinite, sodium hexachloroplatinate, tetrachloroplatinum, tetraammineplatinate, cisplatin, ammonium chloroplatinate, potassium chloroplatinite, tetraammineplatinum nitrate, potassium tetranitroplatinate (II), potassium trichloroammineplatinate (II), and tetraammineplatinum chloride hydrate.

[0025] Furthermore, in step 2.2 and step 2.3, the solvent is selected from one of deionized water, ethylene glycol, diethylene glycol, and triethylene glycol;

[0026] In step 2.3, the catalyst carrier is selected as γ-Al2O3, and the mass of the catalyst carrier is 99 times the total mass of the osmium element and the platinum element.

[0027] Furthermore, in step 2.4, the reducing agent is sodium borohydride, and the amount of sodium borohydride is 100 times the sum of the amounts of osmium and platinum;

[0028] In step 2.5, the washing is performed by washing with deionized water 2 to 3 times and then washing with anhydrous ethanol once.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. The present invention uses an osmium platinum catalyst as a catalyst for the catalytic hydrogenation reduction of nitrogen oxides to synthesize ammonia. The overall preparation process is simple, the reaction conditions are milder, the reaction yield is higher, and the osmium platinum catalyst has lower cost and better performance than pure platinum catalysts.

[0031] 2. In the osmium platinum catalyst used in the present invention, when the molar ratio of osmium element and platinum element is 0.1:0.9, the ammonia yield is the highest. The use of an osmium platinum catalyst with this ratio can not only efficiently treat nitrogen oxides, but also obtain ammonia, an important chemical raw material. Therefore, the use of this type of catalyst has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The figure is a graph showing the change in the yield of ammonia synthesized in Examples 1, 2, 3 and 4 of the present invention as a function of temperature.

[0033] Figure 2 The figure is a graph showing the ammonia yield and synthesis rate of Examples 1, 5, 6, 7, 8 and Comparative Example 1 of the present invention as a function of the osmium metal content.

[0034] Figure 3 NO in Example 1 and Comparative Example 1 of the present invention x A graph showing the conversion rate versus temperature. DETAILED DESCRIPTION

[0035] In order to make the objects, advantages and features of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and specific examples. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0036] In the description of the present invention, it should be noted that if specific conditions are not specified in the examples, the experiments were carried out according to conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used, if the manufacturer is not specified, are all conventional products that can be purchased commercially.

[0037] Example 1

[0038] This embodiment provides a method for synthesizing ammonia based on an osmium platinum catalyst and nitrogen oxides, comprising the following steps:

[0039] Step 1: Prepare 1250 ppm of NO, 12500 ppm of H2, and the rest of Ar.

[0040] Step 2: Weigh 200 mg of osmium platinum catalyst and add it to a tubular reactor containing quartz wool. The osmium platinum catalyst used in this example was prepared as follows:

[0041] According to the total amount of osmium element and platinum element being 0.2 mmol and the molar ratio being 0.1:0.9, 9.6 mg of potassium hexachloroosmate and 73.8 mg of potassium chloroplatinate were taken and mixed respectively, and deionized water was added until the two were completely dissolved to obtain an osmium platinum precursor solution; then, 3853.0 mg of catalyst support γ-Al2O3 was added to the osmium platinum precursor solution, 250 mL of deionized water was added and stirred for 4 hours, and then heated to 60°C, and 756.6 mg of sodium borohydride solution was quickly added, and the mixture was kept warm for 10 minutes. After being taken out and cooled to room temperature, a gray suspension was obtained; finally, the solid product was centrifuged, washed twice with deionized water, and once with anhydrous ethanol, and dried to obtain the required proportion of osmium platinum catalyst.

[0042] Step 3: H2 was introduced into the tubular reactor, and the osmium platinum catalyst was pretreated at 200°C for 1 hour to activate it. The osmium platinum catalyst was then cooled to room temperature under H2 purge. The amount of H2 introduced during this process was 60ccm.

[0043] Step 4: NO, H2 and Ar are simultaneously introduced into a tubular reactor to form a mixed gas. The total flow rate of the mixed gas is 200 ccm, and the flow rates of NO and H2 are 100 ccm respectively. The temperature in the tubular reactor is then raised to 200°C and kept warm, so that the mixed gas reacts under the action of the osmium platinum catalyst for more than 1 hour to obtain a mixed gas containing ammonia, which is further collected to obtain ammonia.

[0044] 300 mL of the mixed gas containing ammonia obtained in this example was extracted with a syringe and then injected into 30 mL of HCl solution with a pH of 3 for absorption. The NH4 in the HCl solution was then measured using ion chromatography and a pH meter. + The content of NH3 can be obtained, and the data of NH3 production and generation rate can be obtained. The generation rate of ammonia in this embodiment is measured by the nitrogen oxide hydrogenation ammonia performance test device to be 296mmol·g metal -1 ·h -1 The yield of ammonia is 97% ( Figure 1 The reaction conditions for synthesizing ammonia in this embodiment are mild, the reaction rate is fast, and the yield is higher than that of the HB process (about 15%).

[0045] Example 2

[0046] This embodiment provides a method for synthesizing ammonia based on an osmium platinum catalyst and nitrogen oxides, comprising the following steps:

[0047] Step 1: Prepare 1250 ppm of NO, 12500 ppm of H2, and the rest of Ar.

[0048] Step 2: Weigh 200 mg of osmium platinum catalyst and add it to a tubular reactor containing quartz wool. The osmium platinum catalyst used in this example was prepared as follows:

[0049] According to the total amount of osmium element and platinum element being 0.2 mmol and the molar ratio of 0.1:0.9, 6.3 mg of osmium (III) chloride hydrate and 73.8 mg of potassium chloroplatinate were taken and mixed respectively, and deionized water was added until the two were completely dissolved to obtain an osmium platinum precursor solution; then 3853.0 mg of catalyst support γ-Al2O3 was added to the osmium platinum precursor solution, 250 mL of deionized water was added and stirred for 3 hours, and then heated to 55°C, and 756.6 mg of sodium borohydride solution was quickly added, and the mixture was kept warm for 7 minutes. After being taken out and cooled to room temperature, a gray suspension was obtained; finally, the solid product was washed twice by centrifugation, washed once with anhydrous ethanol, and dried to obtain the required proportion of osmium platinum catalyst.

[0050] Step 3: H2 was introduced into the tubular reactor, and the osmium platinum catalyst was pretreated at 200°C for 1 hour to activate it. The osmium platinum catalyst was then cooled to room temperature under H2 purge. The amount of H2 introduced during this process was 60ccm.

[0051] Step 4: NO, H2 and Ar are introduced into the tubular reactor at the same time to form a mixed gas. The total flow rate of the mixed gas is 200 ccm. The temperature in the tubular reactor is then raised to 150°C and kept warm. The mixed gas reacts for more than 1 hour under the action of the osmium platinum catalyst to obtain a mixed gas containing ammonia, which is further collected to obtain ammonia.

[0052] 300 mL of the mixed gas containing ammonia obtained in this example was extracted with a syringe and then injected into 30 mL of HCl solution with a pH of 3 for absorption. The NH4 + The content of NH3 can be used to obtain the production and generation rate of NH3. Figure 1 As shown, the reaction conditions of this embodiment are mild, and the yield of synthetic ammonia is 77%, which is relatively high.

[0053] Example 3

[0054] This embodiment provides a method for synthesizing ammonia based on an osmium platinum catalyst and nitrogen oxides, comprising the following steps:

[0055] Step 1: Prepare 1250 ppm of NO, 12500 ppm of H2, and the rest of Ar.

[0056] Step 2: Weigh 200 mg of osmium platinum catalyst and add it to a tubular reactor containing quartz wool; the osmium platinum catalyst used in this example was prepared as follows:

[0057] According to the total amount of osmium element and platinum element being 0.2 mmol and the molar ratio being 0.1:0.9, 9.6 mg of potassium hexachloroosmate and 93.2 mg of chloroplatinic acid hydrate were taken and mixed respectively, and then deionized water was added until the two were completely dissolved to obtain an osmium platinum precursor solution; then 3853.0 mg of catalyst support γ-Al2O3 was added to the osmium platinum precursor solution, 250 mL of deionized water was added and stirred for 2 hours, and then heated to 50°C, and 756.6 mg of sodium borohydride solution was quickly added, and the mixture was kept warm for reaction for 5 minutes. After being taken out, it was cooled to room temperature to obtain a gray suspension; finally, the solid product was washed twice by centrifugation, washed once with anhydrous ethanol, and dried to obtain the required proportion of osmium platinum catalyst.

[0058] Step 3: H2 was introduced into the tubular reactor, and the osmium platinum catalyst was pretreated at 200°C for 1 hour to activate it. The osmium platinum catalyst was then cooled to room temperature under H2 purge. The amount of H2 introduced during this process was 60ccm.

[0059] Step 4: NO, H2 and Ar are introduced into the tubular reactor at the same time to form a mixed gas with a total flow rate of 200 ccm. The temperature in the reactor is then raised to 100°C and kept warm, so that the mixed gas reacts for more than 1 hour under the action of the osmium platinum catalyst to obtain a mixed gas containing ammonia, which is further collected to obtain ammonia.

[0060] 300 mL of the mixed gas containing ammonia obtained in this example was extracted with a syringe and then injected into 30 mL of HCl solution with a pH of 3 for absorption. The NH4 + The content of NH3 can be used to obtain the production and generation rate of NH3. Figure 1 As shown, the reaction conditions of this embodiment are mild, and the yield of synthetic ammonia is 47%, which is relatively low, but still higher than the yield of the HB process (about 15%).

[0061] Example 4

[0062] This embodiment provides a method for synthesizing ammonia based on an osmium platinum catalyst and nitrogen oxides, comprising the following steps:

[0063] Step 1: Prepare 1250 ppm of NO, 12500 ppm of H2, and the rest of Ar.

[0064] Step 2: Weigh 200 mg of osmium platinum catalyst and add it to a tubular reactor containing quartz wool; the osmium platinum catalyst used in this example was prepared as follows:

[0065] According to the total amount of osmium element and platinum element being 0.2 mmol and the molar ratio being 0.1:0.9, 8.8 mg of ammonium chloroosmate and 73.8 mg of potassium chloroplatinate were taken and mixed respectively, and deionized water was added until the two were completely dissolved to obtain an osmium platinum precursor solution; then 3853.0 mg of catalyst support γ-Al2O3 was added to the osmium platinum precursor solution, 250 mL of deionized water was added and stirred for 3 hours, and then heated to 65°C, and 756.6 mg of sodium borohydride solution was quickly added, and the mixture was kept warm for reaction for 3 minutes. After being taken out, it was cooled to room temperature to obtain a gray suspension; finally, the solid product was centrifuged, washed twice with deionized water, and once with anhydrous ethanol, and dried to obtain the required proportion of osmium platinum catalyst.

[0066] Step 3: H2 was introduced into the tubular reactor, and the osmium platinum catalyst was pretreated at 200°C for 1 hour to activate it. The osmium platinum catalyst was then cooled to room temperature under H2 purge. The amount of H2 introduced during this process was 60ccm.

[0067] Step 4: NO, H2 and Ar are introduced into the tubular reactor at the same time to form a mixed gas. The total flow rate of the mixed gas is 200 ccm. The temperature in the tubular reactor is then raised to 50°C and kept warm. The mixed gas is reacted for more than 1 hour under the action of the osmium platinum catalyst to obtain a mixed gas containing ammonia, which is further collected to obtain ammonia.

[0068] 300 mL of the mixed gas containing ammonia obtained in this example was extracted with a syringe and then injected into 30 mL of HCl solution with a pH of 3 for absorption. The NH4 + The content of NH3 can be used to obtain the production and generation rate of NH3. Figure 1 As shown, the reaction conditions of this embodiment are mild, and the yield of synthetic ammonia is 22%, which is relatively low and slightly higher than the yield of the HB process (about 15%).

[0069] Example 5

[0070] This embodiment provides a method for synthesizing ammonia based on an osmium platinum catalyst and nitrogen oxide hydrogenation reduction, comprising the following steps:

[0071] Step 1: Prepare 1250 ppm of NO, 12500 ppm of H2, and the rest of Ar.

[0072] Step 2: Weigh 200 mg of osmium platinum catalyst and add it to a tubular reactor containing quartz wool; the osmium platinum catalyst used in this example was prepared as follows:

[0073] According to the total amount of osmium element and platinum element being 0.2 mmol and the molar ratio being 0.3:0.7, 9.6 mg of potassium hexachloroosmate and 73.8 mg of potassium chloroplatinate were taken respectively and mixed, and then deionized water was added until the two were completely dissolved to obtain an osmium platinum precursor solution; then 3833.8 mg of catalyst support γ-Al2O3 was added to the osmium platinum precursor solution, 250 mL of deionized water was added and stirred for 4 hours, and then heated to 60°C, and 756.6 mg of sodium borohydride solution was quickly added, and the mixture was kept warm for 10 minutes. After being taken out and cooled to room temperature, a gray suspension was obtained; finally, the solid product was centrifuged, washed twice with deionized water, and once with anhydrous ethanol, and dried to obtain the required proportion of osmium platinum catalyst.

[0074] Step 3: H2 was introduced into the tubular reactor, and the osmium platinum catalyst was pretreated at 200°C for 1 hour to activate it. The osmium platinum catalyst was then cooled to room temperature under H2 purge. The amount of H2 introduced during this process was 60ccm.

[0075] Step 4: NO, H2 and Ar are introduced into the tubular reactor at the same time to form a mixed gas with a total flow rate of 200 ccm. The temperature in the reactor is then raised to 200°C and kept warm, so that the mixed gas reacts for more than 1 hour under the action of the osmium platinum catalyst to obtain a mixed gas containing ammonia, which is further collected to obtain ammonia.

[0076] 300 mL of the mixed gas containing ammonia obtained in this example was extracted with a syringe and then injected into 30 mL of HCl solution with a pH of 3 for absorption. The NH4 + The content of NH3 can be determined, and then the production and generation rate of NH3 and other data can be determined.

[0077] like Figure 2 As shown, the generation rate of ammonia in this embodiment is 271mmol·gmetal -1 ·h -1 , with a yield of 88%. The reaction conditions for synthesizing ammonia in this embodiment are mild, the reaction rate is fast, and the yield is high. Compared with Example 1, the content of osmium in the osmium platinum catalyst in this embodiment is increased, and the ammonia generation rate and yield are both reduced.

[0078] Example 6

[0079] This embodiment provides a method for synthesizing ammonia based on an osmium platinum catalyst and nitrogen oxides, comprising the following steps:

[0080] Step 1: Prepare 1250 ppm of NO, 12500 ppm of H2, and the rest of Ar.

[0081] Step 2: Weigh 200 mg of osmium platinum catalyst and add it to a tubular reactor containing quartz wool; the osmium platinum catalyst used in this example was prepared as follows:

[0082] According to the total amount of osmium element and platinum element being 0.2 mmol and the molar ratio being 0.5:0.5, 9.6 mg of potassium hexachloroosmate and 73.8 mg of potassium chloroplatinate were taken and mixed respectively, and deionized water was added until the two were completely dissolved to obtain an osmium platinum precursor solution; then 3814.6 mg of catalyst support γ-Al2O3 was added to the osmium platinum precursor solution, 250 mL of deionized water was added and stirred for 3 hours, and then heated to 60°C, and 756.6 mg of sodium borohydride solution was quickly added, and the mixture was kept warm for 10 minutes. After being taken out and cooled to room temperature, a gray suspension was obtained; finally, the solid product was centrifuged, washed twice with deionized water, and once with anhydrous ethanol, and dried to obtain the required proportion of osmium platinum catalyst.

[0083] Step 3: H2 was introduced into the tubular reactor, and the osmium platinum catalyst was pretreated at 300°C for 0.5h to activate it, and then the osmium platinum catalyst was cooled to room temperature under H2 purge. The amount of H2 introduced during this process was 60ccm.

[0084] Step 4: NO, H2 and Ar are introduced into the tubular reactor at the same time to form a mixed gas with a total flow rate of 200 ccm. The temperature in the reactor is then raised to 200°C and kept warm, so that the mixed gas reacts for more than 1 hour under the action of the osmium platinum catalyst to obtain a mixed gas containing ammonia, which is further collected to obtain ammonia.

[0085] 300 mL of the mixed gas containing ammonia obtained in this example was extracted with a syringe and then injected into 30 mL of HCl solution with a pH of 3 for absorption. The NH4 + The content of NH3 can be determined, and then the production and generation rate of NH3 and other data can be determined.

[0086] like Figure 2 As shown, the generation rate of ammonia in this embodiment is 261mmol·gmetal -1 ·h -1 , the yield is 85%. The reaction conditions for synthesizing ammonia in this embodiment are mild, the reaction rate is fast, and the yield is high.

[0087] Example 7

[0088] This embodiment provides a method for synthesizing ammonia based on an osmium platinum catalyst and nitrogen oxides, comprising the following steps:

[0089] Step 1: Prepare 1250 ppm of NO, 12500 ppm of H2, and the rest of Ar.

[0090] Step 2: Weigh 200 mg of osmium platinum catalyst and add it to a tubular reactor containing quartz wool; the osmium platinum catalyst used in this example was prepared as follows:

[0091] According to the total amount of osmium element and platinum element being 0.2 mmol and the molar ratio being 0.7:0.3, 9.6 mg of potassium hexachloroosmate and 73.8 mg of potassium chloroplatinate were taken and mixed respectively, and deionized water was added until the two were completely dissolved to obtain an osmium platinum precursor solution; then 3795.4 mg of catalyst support γ-Al2O3 was added to the osmium platinum precursor solution, 250 mL of deionized water was added and stirred for 4 hours, and then heated to 55°C, 756.6 mg of sodium borohydride solution was quickly added, and the mixture was kept warm for 7 minutes. After being taken out and cooled to room temperature, a gray suspension was obtained; finally, the solid product was centrifuged, washed twice with deionized water, and once with anhydrous ethanol, and dried to obtain the required proportion of osmium platinum catalyst.

[0092] Step 3: H2 is introduced into the tubular reactor, and the osmium platinum catalyst is pretreated at 300°C for 2 hours to activate it. The osmium platinum catalyst is then cooled to room temperature under H2 purge. The amount of H2 introduced during this process is 60ccm.

[0093] Step 4: NO, H2 and Ar are introduced into the tubular reactor at the same time to form a mixed gas. The total flow rate of the mixed gas is 200 ccm, and the temperature in the tubular reactor is raised to 200°C and then kept warm. The mixed gas reacts for more than 1 hour under the action of the osmium platinum catalyst to obtain a mixed gas containing ammonia, which is further collected to obtain ammonia.

[0094] 300 mL of the mixed gas containing ammonia obtained in this example was extracted with a syringe and then injected into 30 mL of HCl solution with a pH of 3 for absorption. The NH4 + The content of NH3 can be measured, and then the data such as NH3 production and generation rate can be obtained.

[0095] like Figure 2 As shown, the generation rate of ammonia in this embodiment is 267mmol·gmetal -1 ·h -1 , the yield is 87%. The reaction conditions for synthesizing ammonia in this embodiment are mild, the reaction rate is fast, and the yield is high.

[0096] Example 8

[0097] This embodiment provides a method for synthesizing ammonia based on an osmium platinum catalyst and nitrogen oxides, comprising the following steps:

[0098] Step 1: Prepare 1250 ppm of NO, 12500 ppm of H2, and the rest of Ar.

[0099] Step 2: Weigh 200 mg of osmium platinum catalyst and add it to a tubular reactor containing quartz wool; the osmium platinum catalyst used in this example was prepared as follows:

[0100] According to the total amount of osmium element and platinum element being 0.2 mmol and the molar ratio being 0.9:0.1, 9.6 mg of potassium hexachloroosmate and 73.8 mg of potassium chloroplatinate were taken and mixed respectively, and deionized water was added until the two were completely dissolved to obtain an osmium platinum precursor solution; then 3776.2 mg of catalyst support γ-Al2O3 was added to the osmium platinum precursor solution, 250 mL of deionized water was added and stirred for 4 hours, and then heated to 50°C, and 756.6 mg of sodium borohydride solution was quickly added, and the mixture was kept warm for 12 minutes. After being taken out and cooled to room temperature, a gray suspension was obtained; finally, the solid product was centrifuged, washed twice with deionized water, and once with anhydrous ethanol, and dried to obtain the required proportion of osmium platinum catalyst.

[0101] Step 3: H2 was introduced into the tubular reactor, and the osmium platinum catalyst was pretreated at 400°C for 0.5h to activate it, and then the osmium platinum catalyst was cooled to room temperature under H2 purge. The amount of H2 introduced during this process was 60ccm.

[0102] Step 4: NO, H2 and Ar are introduced into the tubular reactor at the same time to form a mixed gas with a total flow rate of 200 ccm. The temperature in the reactor is then raised to 200°C and kept warm, so that the mixed gas reacts for more than 1 hour under the action of the osmium platinum catalyst to obtain a mixed gas containing ammonia, which is further collected to obtain ammonia.

[0103] 300 mL of the mixed gas containing ammonia obtained in this example was extracted with a syringe and then injected into 30 mL of HCl solution with a pH of 3 for absorption. The NH4 + The content of NH3 can be measured, and then the data such as NH3 production and generation rate can be obtained.

[0104] like Figure 2 As shown, the generation rate of ammonia in this embodiment is 252mmol·gmetal -1 ·h -1 , the yield is 82%. The reaction conditions for synthesizing ammonia in this embodiment are mild, the reaction rate is fast, and the yield is high.

[0105] Example 9

[0106] This embodiment provides a method for synthesizing ammonia based on an osmium platinum catalyst and nitrogen oxides, comprising the following steps:

[0107] Step 1: Prepare 1250 ppm of NO, 12500 ppm of H2, and the rest of Ar.

[0108] Step 2: Weigh 150 mg of osmium platinum catalyst and add it to a tubular reactor containing quartz wool; the osmium platinum catalyst used in this example was prepared as follows:

[0109] According to the total amount of osmium element and platinum element being 0.2 mmol and the molar ratio being 0.1:0.9, 9.6 mg of potassium hexachloroosmate and 73.8 mg of potassium chloroplatinate were taken respectively and mixed, and ethylene glycol was added until the two were completely dissolved to obtain an osmium platinum precursor solution; then, 3849.1 mg of catalyst support γ-Al2O3 was added to the osmium platinum precursor solution, 250 mL of ethylene glycol was added and stirred for 4 hours, and then heated to 60°C, and 756.6 mg of sodium borohydride solution was quickly added, and the mixture was kept warm for 10 minutes. After being taken out and cooled to room temperature, a gray suspension was obtained; finally, the solid product was washed twice by centrifugation, washed once with anhydrous ethanol, and dried to obtain the required proportion of osmium platinum catalyst.

[0110] Step 3: H2 was introduced into the tubular reactor, and the osmium platinum catalyst was pretreated at 400°C for 0.5h to activate it, and then the osmium platinum catalyst was cooled to room temperature under H2 purge. The amount of H2 introduced during this process was 60ccm.

[0111] Step 4: NO, H2 and Ar are introduced into the tubular reactor at the same time to form a mixed gas. The total flow rate of the mixed gas is 200 ccm. The temperature in the tubular reactor is then raised to 200°C and kept warm. The mixed gas is reacted under the action of the osmium platinum catalyst for more than 1 hour to obtain a mixed gas containing ammonia, which is further collected to obtain ammonia.

[0112] 300 mL of the mixed gas containing ammonia obtained in this example was extracted with a syringe and then injected into 30 mL of HCl solution with a pH of 3 for absorption. The NH4 + The content of NH3 can be determined, and then the production and generation rate of NH3 and other data can be determined.

[0113] Example 10

[0114] This embodiment provides a method for synthesizing ammonia based on an osmium platinum catalyst and nitrogen oxides, comprising the following steps:

[0115] Step 1: Prepare 1250 ppm of NO, 12500 ppm of H2, and the rest of Ar.

[0116] Step 2: Weigh 100 mg of osmium platinum catalyst and add it to a tubular reactor containing quartz wool; the osmium platinum catalyst used in this example was prepared as follows:

[0117] According to the total amount of osmium element and platinum element being 0.2 mmol and the molar ratio being 0.1:0.9, 9.6 mg of potassium hexachloroosmate and 73.8 mg of potassium chloroplatinate were taken and mixed respectively, and then diethylene glycol was added until the two were completely dissolved to obtain an osmium platinum precursor solution; then 3845.2 mg of catalyst support γ-Al2O3 was added to the osmium platinum precursor solution, 250 mL of diethylene glycol was added and stirred for 3 hours, and then heated to 60°C, and 756.6 mg of sodium borohydride solution was quickly added, and the mixture was kept warm for 7 minutes. After being taken out and cooled to room temperature, a gray suspension was obtained; finally, the solid product was washed twice by centrifugation, washed once with anhydrous ethanol, and dried to obtain the required proportion of osmium platinum catalyst.

[0118] Step 3: H2 was introduced into the tubular reactor, and the osmium platinum catalyst was pretreated at 200°C for 1 hour to activate it. The osmium platinum catalyst was then cooled to room temperature under H2 purge. The amount of H2 introduced during this process was 60ccm.

[0119] Step 4: NO, H2 and Ar are introduced into the tubular reactor at the same time to form a mixed gas with a total flow rate of 200 ccm. The temperature in the reactor is then raised to 200°C and kept warm, so that the mixed gas reacts for more than 1 hour under the action of the osmium platinum catalyst to obtain a mixed gas containing ammonia, which is further collected to obtain ammonia.

[0120] 300 mL of the mixed gas containing ammonia obtained in this example was extracted with a syringe and then injected into 30 mL of HCl solution with a pH of 3 for absorption. The NH4 + The content of NH3 can be used to obtain data such as the production and generation rate of NH3.

[0121] Example 11

[0122] This embodiment provides a method for synthesizing ammonia based on an osmium platinum catalyst and nitrogen oxides, comprising the following steps:

[0123] Step 1: Prepare 1250 ppm of NO, 12500 ppm of H2, and the rest of Ar.

[0124] Step 2: Weigh 50 mg of osmium platinum catalyst and add it to a tubular reactor containing quartz wool; the osmium platinum catalyst used in this example was prepared as follows:

[0125] According to the total amount of osmium element and platinum element being 0.2 mmol and the molar ratio being 0.1:0.9, 9.6 mg of potassium hexachloroosmate and 73.8 mg of potassium chloroplatinate were taken and mixed respectively, and deionized water was added until the two were completely dissolved to obtain an osmium platinum precursor solution; then, 3853.0 mg of catalyst support γ-Al2O3 was added to the osmium platinum precursor solution, 200 mL of deionized water was added and stirred for 3 hours, and then heated to 65°C, and 756.6 mg of sodium borohydride solution was quickly added, and the mixture was kept warm for 12 minutes. After being taken out and cooled to room temperature, a gray suspension was obtained; finally, the solid product was centrifuged, washed twice with deionized water, and once with anhydrous ethanol, and dried to obtain the required proportion of osmium platinum catalyst.

[0126] Step 3: H2 was introduced into the tubular reactor, and the osmium platinum catalyst was pretreated at 400°C for 0.5h to activate it, and then the osmium platinum catalyst was cooled to room temperature under H2 purge. The amount of H2 introduced during this process was 60ccm.

[0127] Step 4: NO, H2 and Ar are introduced into the tubular reactor at the same time to form a mixed gas with a total flow rate of 200 ccm. The temperature in the reactor is then raised to 200°C and kept warm, so that the mixed gas reacts for more than 1 hour under the action of the osmium platinum catalyst to obtain a mixed gas containing ammonia, which is further collected to obtain ammonia.

[0128] 300 mL of the mixed gas containing ammonia obtained in this example was extracted with a syringe and then injected into 30 mL of HCl solution with a pH of 3 for absorption. The NH4 + The content can be used to obtain data such as NH3 production and generation rate.

[0129] Example 12

[0130] This embodiment provides a method for synthesizing ammonia based on an osmium platinum catalyst and nitrogen oxides, comprising the following steps:

[0131] Step 1: Prepare 7500ppm of NO, 75000ppm of H2, and the rest of Ar.

[0132] Step 2: Weigh 200 mg of osmium platinum catalyst and add it to a tubular reactor containing quartz wool; the osmium platinum catalyst used in this example was prepared as follows:

[0133] According to the total amount of osmium element and platinum element being 0.2 mmol and the molar ratio being 0.1:0.9, 9.6 mg of potassium hexachloroosmate and 73.8 mg of potassium chloroplatinate were taken respectively and mixed, and then deionized water was added until the two were completely dissolved to obtain an osmium platinum precursor solution; then 3853.0 mg of catalyst support γ-Al2O3 was added to the osmium platinum precursor solution, 150 mL of deionized water was added and stirred for 3 hours, and then heated to 65°C, and 75.6 mg of sodium borohydride solution was quickly added, and the mixture was kept warm for 12 minutes. After being taken out and cooled to room temperature, a gray suspension was obtained; finally, the solid product was centrifuged, washed twice with deionized water, and once with anhydrous ethanol, and dried to obtain the required proportion of osmium platinum catalyst.

[0134] Step 3: H2 was introduced into the tubular reactor, and the osmium platinum catalyst was pretreated at 400°C for 0.5h to activate it, and then the osmium platinum catalyst was cooled to room temperature under H2 purge. The amount of H2 introduced during this process was 60ccm.

[0135] Step 4: NO, H2 and Ar are introduced into the tubular reactor at the same time to form a mixed gas with a total flow rate of 200 ccm. The temperature in the reactor is then raised to 200°C and kept warm, so that the mixed gas reacts for more than 1 hour under the action of the osmium platinum catalyst to obtain a mixed gas containing ammonia, which is further collected to obtain ammonia.

[0136] 300 mL of the mixed gas containing ammonia obtained in this example was extracted with a syringe and then injected into 30 mL of HCl solution with a pH of 3 for absorption. The NH4 + content, and then determine data such as NH3 production and generation rate.

[0137] Example 13

[0138] This embodiment provides a method for synthesizing ammonia based on an osmium platinum catalyst and nitrogen oxide hydrogenation reduction, comprising the following steps:

[0139] Step 1: Prepare 15000ppm of NO, 150000ppm of H2, and the rest of Ar.

[0140] Step 2: Weigh 200 mg of osmium platinum catalyst and add it to a tubular reactor containing quartz wool; the osmium platinum catalyst used in this example was prepared as follows:

[0141] According to the total amount of osmium element and platinum element being 0.2 mmol and the molar ratio being 0.1:0.9, 9.6 mg of potassium hexachloroosmate and 73.8 mg of potassium chloroplatinate were taken and mixed respectively, and deionized water was added until the two were completely dissolved to obtain an osmium platinum precursor solution; then, 3853.0 mg of catalyst support γ-Al2O3 was added to the osmium platinum precursor solution, 250 mL of deionized water was added and stirred for 3 hours, and then heated to 65°C, and 227.0 mg of sodium borohydride solution was quickly added, and the mixture was kept warm for 10 minutes. After being taken out and cooled to room temperature, a gray suspension was obtained; finally, the solid product was centrifuged, washed twice with deionized water, and once with anhydrous ethanol, and dried to obtain the required proportion of osmium platinum catalyst.

[0142] Step 3: H2 was introduced into the tubular reactor, and the osmium platinum catalyst was pretreated at 300°C for 0.5h to activate it, and then the osmium platinum catalyst was cooled to room temperature under H2 purge. The amount of H2 introduced during this process was 50ccm.

[0143] Step 4: NO, H2 and Ar are introduced into the tubular reactor at the same time to form a mixed gas with a total flow rate of 200 ccm. The temperature in the reactor is then raised to 200°C and kept warm, so that the mixed gas reacts for more than 1 hour under the action of the osmium platinum catalyst to obtain a mixed gas containing ammonia, which is further collected to obtain ammonia.

[0144] 300 mL of the mixed gas containing ammonia obtained in this example was extracted with a syringe and then injected into 30 mL of HCl solution with a pH of 3 for absorption. The NH4 + content, and then determine data such as NH3 production and generation rate.

[0145] Example 14

[0146] This embodiment provides a method for synthesizing ammonia based on an osmium platinum catalyst and nitrogen oxide hydrogenation reduction, comprising the following steps:

[0147] Step 1: Prepare 25000ppm of NO, 250000ppm of H2, and the rest of Ar.

[0148] Step 2: Weigh 200 mg of osmium platinum catalyst and add it to a tubular reactor containing quartz wool; the osmium platinum catalyst used in this example was prepared as follows:

[0149] According to the total amount of osmium element and platinum element being 0.1 mmol and the molar ratio being 0.1:0.9, 4.8 mg of potassium hexachloroosmate and 36.9 mg of potassium chloroplatinate were taken and mixed respectively, and deionized water was added until the two were completely dissolved to obtain an osmium platinum precursor solution; then, 1926.5 mg of catalyst support γ-Al2O3 was added to the osmium platinum precursor solution, 250 mL of deionized water was added and stirred for 3 hours, and then heated to 65°C, and 378.3 mg of sodium borohydride solution was quickly added, and the mixture was kept warm for 12 minutes. After being taken out and cooled to room temperature, a gray suspension was obtained; finally, the solid product was centrifuged, washed twice with deionized water, and once with anhydrous ethanol, and dried to obtain the required proportion of osmium platinum catalyst.

[0150] Step 3: H2 was introduced into the tubular reactor, and the osmium platinum catalyst was pretreated at 200°C for 1 hour to activate it. The osmium platinum catalyst was then cooled to room temperature under H2 purge. The amount of H2 introduced during this process was 40ccm.

[0151] Step 4: NO, H2 and Ar are introduced into the tubular reactor at the same time to form a mixed gas with a total flow rate of 200 ccm. The temperature in the reactor is then raised to 200°C and kept warm, so that the mixed gas reacts for more than 1 hour under the action of the osmium platinum catalyst to obtain a mixed gas containing ammonia, which is further collected to obtain ammonia.

[0152] 300 mL of the mixed gas containing ammonia obtained in this example was extracted with a syringe and then injected into 30 mL of HCl solution with a pH of 3 for absorption. The NH4 + content, and then determine data such as NH3 production and generation rate.

[0153] Example 15

[0154] This embodiment provides a method for synthesizing ammonia based on an osmium platinum catalyst and nitrogen oxide hydrogenation reduction, comprising the following steps:

[0155] Step 1: Prepare 25000ppm of NO, 250000ppm of H2, and the rest of Ar.

[0156] Step 2: Weigh 200 mg of osmium platinum catalyst and add it to a tubular reactor containing quartz wool; the osmium platinum catalyst used in this example was prepared as follows:

[0157] According to the total amount of osmium element and platinum element being 0.4 mmol and the molar ratio being 0.1:0.9, 19.2 mg of potassium hexachloroosmate and 147.5 mg of potassium chloroplatinate were taken and mixed respectively, and deionized water was added until the two were completely dissolved to obtain an osmium platinum precursor solution; then 7706.0 mg of catalyst support γ-Al2O3 was added to the osmium platinum precursor solution, 250 mL of deionized water was added and stirred for 3 hours, and then heated to 65°C, and 2156.8 mg of potassium borohydride solution was quickly added, and the mixture was kept warm for 12 minutes. After being taken out and cooled to room temperature, a gray suspension was obtained; finally, the solid product was centrifuged, washed twice with deionized water, and once with anhydrous ethanol, and dried to obtain the required proportion of osmium platinum catalyst.

[0158] Step 3: H2 was introduced into the tubular reactor, and the osmium platinum catalyst was pretreated at 200°C for 1 hour to activate it. The osmium platinum catalyst was then cooled to room temperature under H2 purge. The amount of H2 introduced during this process was 40ccm.

[0159] Step 4: NO, H2 and Ar are introduced into a tubular reactor at the same time to form a mixed gas with a total flow rate of 800 ccm. The temperature in the reactor is then raised to 200°C and kept warm, so that the mixed gas reacts for more than 1 hour under the action of the osmium platinum catalyst to obtain a mixed gas containing ammonia, which is further collected to obtain ammonia.

[0160] 300 mL of the mixed gas containing ammonia obtained in this example was extracted with a syringe and then injected into 30 mL of HCl solution with a pH of 3 for absorption. The NH4 + content, and then determine data such as NH3 production and generation rate.

[0161] Example 16

[0162] This embodiment provides a method for synthesizing ammonia based on an osmium platinum catalyst and nitrogen oxide hydrogenation reduction, comprising the following steps:

[0163] Step 1: Prepare 25000ppm of NO, 250000ppm of H2, and the rest of Ar.

[0164] Step 2: Weigh 50 mg of osmium platinum catalyst and add it to a tubular reactor containing quartz wool; the osmium platinum catalyst used in this example was prepared as follows:

[0165] According to the total amount of osmium element and platinum element being 0.8 mmol and the molar ratio being 0.1:0.9, 38.5 mg of potassium hexachloroosmate and 295.1 mg of potassium chloroplatinate were taken and mixed respectively, and deionized water was added until the two were completely dissolved to obtain an osmium platinum precursor solution; then, 15411.9 mg of catalyst support γ-Al2O3 was added to the osmium platinum precursor solution, 250 mL of deionized water was added and stirred for 3 hours, and then heated to 65°C, and 3026.4 mg of sodium borohydride solution was quickly added, and the mixture was kept warm for 12 minutes. After being taken out and cooled to room temperature, a gray suspension was obtained; finally, the solid product was centrifuged, washed twice with deionized water, and once with anhydrous ethanol, and dried to obtain the required proportion of osmium platinum catalyst.

[0166] Step 3: H2 was introduced into the tubular reactor, and the osmium platinum catalyst was pretreated at 200°C for 1 hour to activate it. The osmium platinum catalyst was then cooled to room temperature under H2 purge. The amount of H2 introduced during this process was 40ccm.

[0167] Step 4: NO, H2 and Ar are introduced into a tubular reactor at the same time to form a mixed gas with a total flow rate of 100 ccm. The temperature in the reactor is then raised to 200°C and kept warm, so that the mixed gas reacts for more than 1 hour under the action of the osmium platinum catalyst to obtain a mixed gas containing ammonia, which is further collected to obtain ammonia.

[0168] 300 mL of the mixed gas containing ammonia obtained in this example was extracted with a syringe and then injected into 30 mL of HCl solution with a pH of 3 for absorption. The NH4 + content, and then determine data such as NH3 production and generation rate.

[0169] Comparative Example 1

[0170] This comparative example provides a method for synthesizing ammonia based on a pure platinum catalyst and nitrogen oxides, comprising the following steps:

[0171] Step 1: Prepare 1250 ppm of NO, 12500 ppm of H2, and the rest of Ar.

[0172] Step 2: Add 200 mg of pure platinum catalyst to a tubular reactor containing quartz wool. The osmium platinum catalyst used in this example was prepared as follows:

[0173] Based on the amount of platinum element substance being 0.2 mmol, 82.0 mg of potassium chloroplatinate was taken and mixed, and deionized water was added until both were completely dissolved to obtain a platinum precursor solution; then, 3862.6 mg of catalyst support γ-Al2O3 was added to the platinum precursor solution, 250 mL of deionized water was added and stirred for 4 hours, and then heated to 60°C, and 756.6 mg of sodium borohydride solution was quickly added, and the mixture was kept warm for 10 minutes. After being taken out and cooled to room temperature, a gray suspension was obtained; finally, the solid product was washed twice by centrifugation and deionized water and once by anhydrous ethanol, and then dried to obtain a pure platinum catalyst.

[0174] Step 3: Pre-treat with H2 at 200°C for 1 h, and then cool to room temperature under H2 purge.

[0175] Step 4: NO, H2 and Ar are introduced into the tubular reactor at the same time to form a mixed gas with a total flow rate of 200 ccm. The temperature is gradually raised to 200°C and the reaction is carried out at a constant temperature for more than 1 hour. 300 mL of the mixed gas containing ammonia is collected.

[0176] 300 mL of mixed gas containing ammonia in this comparative example was extracted with a syringe and then injected into 30 mL of HCl solution with pH = 3 for absorption. The NH4 + content, and then determine data such as NH3 production and generation rate.

[0177] like Figure 2 As shown, the generation rate of ammonia synthesis in this comparative example is 267mmol·g metal -1 ·h -1 , with a yield of 87%. The reaction conditions for synthesizing ammonia in this comparative example are mild, the reaction rate is fast, and the yield is high, but the cost of the pure platinum catalyst is relatively high, and the ammonia yield is not as high as that of the osmium platinum catalyst with a molar ratio of osmium element to platinum element of 0.1:0.9.

[0178] Figure 3 The NO in Example 1 and Comparative Example 1 x The graph of conversion rate changes with temperature, where the green line represents the use of an osmium-platinum catalyst with a molar ratio of osmium to platinum of 0.1:0.9, and the blue line represents the use of a pure platinum catalyst. The graph shows that the use of an osmium-platinum catalyst, especially an osmium-platinum catalyst with a molar ratio of osmium to platinum of 0.1:0.9, as a catalyst for hydrogen reduction of nitrogen oxides has a higher T for NO conversion. 50 The value is significantly smaller than that of pure platinum catalyst. Therefore, the catalytic activity of the osmium platinum catalyst used in Example 1 is better than that of pure platinum catalyst.

[0179] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. A method for synthesizing ammonia based on an osmium platinum catalyst and nitrogen oxides, characterized in that: The following steps are involved: Step 1, preparing NO, H2 and an inert gas according to preset required amounts; the volume concentration ratio of the NO and H2 when flowing into the reactor at a uniform flow rate is (0.25% to 5%): (2.5% to 50%), and the rest is inert gas; Step 2, weighing an osmium platinum catalyst and adding it to a tubular reactor containing quartz wool; defining the amount of the osmium platinum catalyst as m, in mg, and the preset flow rate of NO gas entering the reactor as v, in ccm, then the amount of the osmium platinum catalyst m = (0.5-2) v; the molar ratio of osmium element and platinum element in the osmium platinum catalyst is 0.05-0.75:0.25-0.95; Step 3, introducing H2 into the tubular reactor and heating the tubular reactor to 200-400°C, pretreating the osmium platinum catalyst at this temperature to activate it, and then continuing to cool the osmium platinum catalyst to room temperature under H2 purge; the H2 flow rate is 30% to 100% of the H2 flow rate during the reaction; Step 4: Simultaneously, the NO, H2, and inert gas prepared in step 1 are introduced into the tubular reactor at a uniform flow rate to form a mixed gas, and the temperature in the tubular reactor is raised to 50-200°C and then kept warm, so that the mixed gas reacts for 30 minutes to 3 hours under the action of the osmium platinum catalyst, and NO is converted into ammonia and collected, thereby completing the ammonia synthesis based on the osmium platinum catalyst and nitrogen oxides.

2. The method for synthesizing ammonia based on an osmium platinum catalyst and nitrogen oxides according to claim 1, characterized in that: In step 1, the volume concentration ratio of NO and H2 is 0.25%:2.5%.

3. The method for synthesizing ammonia based on an osmium platinum catalyst and nitrogen oxides according to claim 1, characterized in that: In step 2, the molar ratio of osmium element to platinum element in the osmium platinum catalyst is 0.05-0.15:0.85-0.

95.

4. The method for synthesizing ammonia based on an osmium platinum catalyst and nitrogen oxides according to claim 3, characterized in that: In step 2, the molar ratio of osmium element to platinum element in the osmium platinum catalyst is 0.1:0.

9.

5. The method for synthesizing ammonia based on an osmium platinum catalyst and nitrogen oxides according to claim 1, characterized in that: In step 3, the flow rate of H2 is 40-60 ccm; the pretreatment time is 0.5-2 h.

6. The method for synthesizing ammonia based on an osmium platinum catalyst and nitrogen oxides according to claim 1, characterized in that: In step 4, when NO, H2 and an inert gas are introduced into the tubular reactor to form a mixed gas, the flow rate of NO is 100 ccm and the flow rate of H2 is 100 ccm.

7. The method for synthesizing ammonia based on an osmium platinum catalyst and nitrogen oxides according to claim 1, characterized in that: In step 2, the osmium platinum catalyst is prepared by the following method: 2.

1. Weigh the osmium compound and the platinum compound based on the predetermined ratio of osmium and platinum in the osmium-platinum catalyst and the total amount of osmium and platinum in the desired osmium-platinum catalyst; 2.

2. Add the osmium compound and the platinum compound into a container respectively, and then add a solvent until the osmium compound and the platinum compound are completely dissolved to obtain an osmium platinum precursor solution; 2.

3. Adding the catalyst support and the solvent to the osmium platinum precursor solution in sequence and stirring uniformly to obtain a mixed solution; the mass of the catalyst support is N times the total mass of the osmium element and the platinum element, where 0≤N≤99; the total mass concentration of the osmium element and the platinum element in the mixed solution is 20 mg / L to 10 g / L; the total mass of the osmium element and the platinum element is calculated by the total amount of the osmium element and the platinum element and the ratio of the predetermined amount of the substance; 2.

4. Adding a reducing agent to the mixed solution at a temperature ranging from room temperature to below the boiling point of the solvent, and carrying out a heat-insulating reaction, followed by cooling to room temperature to obtain a suspension; the amount of the reducing agent is 2 to 200 times the sum of the amounts of the osmium element and the platinum element; 2.

5. Centrifuge, wash and dry the suspension in sequence to obtain the osmium platinum catalyst.

8. The method for synthesizing ammonia based on an osmium platinum catalyst and nitrogen oxides according to claim 7, characterized in that: In step 2.1, the osmium compound is selected from one or more of potassium hexachloroosmate, osmium (III) chloride hydrate, ammonium chloroosmate, sodium hexachloroosmium (IV) dihydrate, triosmium dodecacarbonyl, bis(cyclopentadienyl)osmium, and potassium osmate dihydrate; The platinum compound is selected from one or more of potassium chloroplatinate, chloroplatinic acid hydrate, platinum tetrachloride, sodium chloroplatinite, sodium hexachloroplatinate, tetrachloroplatinum, tetraammineplatinate, cisplatin, ammonium chloroplatinate, potassium chloroplatinite, tetraammineplatinum nitrate, potassium tetranitroplatinate (II), potassium trichloroammineplatinate (II), and tetraammineplatinum chloride hydrate.

9. The method for synthesizing ammonia based on an osmium platinum catalyst and nitrogen oxides according to claim 8, characterized in that: In step 2.2 and step 2.3, the solvent is selected from one of deionized water, ethylene glycol, diethylene glycol, and triethylene glycol; In step 2.3, the catalyst carrier is selected as γ-Al2O3, and the mass of the catalyst carrier is 99 times the total mass of the osmium element and the platinum element.

10. The method for synthesizing ammonia based on an osmium platinum catalyst and nitrogen oxides according to claim 9, characterized in that: In step 2.4, the reducing agent is sodium borohydride, and the amount of sodium borohydride is 100 times the sum of the amounts of osmium and platinum; In step 2.5, the washing is performed by washing with deionized water 2 to 3 times and then washing with anhydrous ethanol once.

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