Preparation method of normal-temperature catalytic bimetallic catalyst and preparation method of ultra-pure nitrogen

Abstract

The invention provides a preparation method of a normal-temperature catalytic bimetallic catalyst and a preparation method of ultrapure nitrogen, and the preparation method of the normal-temperature catalytic bimetallic catalyst comprises the following steps: adding an oxidizing agent into a metal salt aqueous solution, and adjusting the pH value; and carrying out ultrasonic aging on the coprecipitate for 20-40 minutes, aging for 10-14 hours, filtering and washing to obtain a filter cake, drying the filter cake overnight at 95-125 DEG C, and calcining for 2-6 hours at 350-450 DEG C in the air atmosphere. The bimetallic catalyst provided by the invention has a good effect of simultaneously removing carbon monoxide and hydrogen.

Description

Technical Field

[0001] This invention belongs to the field of industrial gas purification, specifically relating to a method for preparing a room-temperature catalytic bimetallic catalyst and a method for preparing ultrapure nitrogen. Background Technology

[0002] With the advancement of science and technology, industrial gases have become an indispensable basic element of the national economy, occupying a pivotal position in the strategic layout of the national economy. Especially under the wave of the electronic information technology era, the booming development of industries such as integrated circuits and display panels has further increased the demand for high-purity electronic gases. As an important component of bulk electronic gases, high-purity nitrogen is increasingly widely used in the integrated circuit and display panel industries, leading to a surge in demand. Currently, high-purity nitrogen is mainly obtained from nitrogen production units through cryogenic distillation. However, the gas obtained in this process is often mixed with permanent gaseous impurities such as H2 and CO. These impurities have weak physical adsorption, strong chemical inertness, and require harsh phase transition conditions, making it difficult for existing processes to achieve efficient deep removal. With the increasing demands for high-purity gas purity and the continuous advancement of dual-carbon goals, the control of impurity content in gases and energy consumption in purification processes is becoming increasingly stringent. Therefore, the development of efficient nitrogen purification technologies is particularly important.

[0003] Currently, cryogenic distillation, as the mainstream nitrogen production process, can reduce the impurity content in nitrogen to the ppm level, meeting the requirements of the national standard GB / T8979-2008. However, as the "lifeblood" of the electronics and information industry, ultrapure nitrogen requires a purity level of ppb for advanced node wafer production lines below 7nm. Currently, economically viable ppb-level ultrapure nitrogen production technologies are mainly monopolized by foreign companies. To date, there are very few reports, both domestically and internationally, on bimetallic oxide catalysts and their preparation technologies for the simultaneous deep removal of CO and H2 from ultrapure nitrogen.

[0004] While precious metals generally possess excellent low-temperature catalytic performance, they still have limitations in applications such as the preparation of ultrapure nitrogen. Although platinum (Pt)-based catalysts can achieve room-temperature catalytic oxidation of carbon monoxide (CO), they struggle to efficiently remove low-concentration CO (<500 ppm) under low-temperature drying conditions and lack the ability to catalytically oxidize hydrogen (H2) at room temperature. On one hand, their catalytic stability is extremely poor, and their effective reaction time is short, far from meeting the long-term operational requirements of industrial production. On the other hand, they are difficult to achieve catalytic oxidation of even lower concentrations (e.g., approaching 10 ppm and below) of CO and H2, making it difficult to support applications with extremely high impurity content requirements, such as the preparation of ultrapure nitrogen. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for preparing a room-temperature catalytic bimetallic catalyst, comprising the following steps: adding an oxidant to an aqueous solution of a metal salt and adjusting the pH; ultrasonically aging the coprecipitate for 20-40 minutes, aging it for 10-14 hours, obtaining a filter cake after filtration and washing, drying the filter cake overnight at 95℃-125℃, and then calcining it at 350℃-450℃ in an air atmosphere for 2-6 hours.

[0006] Preferably, the calcination step further includes the following step: using the calcined oxide catalyst as a support, ultrasonically impregnating it with 15-30% by mass of other metal salts, followed by drying and calcination at 380℃-420℃ to obtain a bimetallic catalyst.

[0007] Preferably, the metal salt in the aqueous solution is a manganese salt, the oxide obtained after calcination is manganese dioxide, and the other metal salts are copper, silver, or cobalt.

[0008] Preferably, the sample is ultrasonically impregnated with 18-23% by mass of other metal salts.

[0009] Preferably, the aqueous solution of the metal salt contains copper and manganese, with a molar ratio of copper to manganese of (0.02-3):1, and is calcined in an air atmosphere for 3-5 hours to obtain a bimetallic catalyst.

[0010] Preferably, the aqueous solution of the metal salt is prepared from manganese acetate and copper acetate.

[0011] Preferably, the ultrasonic aging time is 25-35 minutes; the aging time is 11-13 hours.

[0012] Preferably, the calcination temperature is 380℃-410℃.

[0013] Preferably, the oxidant contains a supporting ion, wherein the supporting ion is H+. + K + Na + Li + One or more of the following: ammonium ions.

[0014] This invention also provides a method for preparing ultrapure nitrogen, comprising: compressing air, drying and filtering it, and then passing it into a reactor; the gas exiting the reactor is then distilled to obtain ultrapure nitrogen; the reactor is filled with a bimetallic catalyst, which is prepared by the method described above for preparing a room-temperature catalytic bimetallic catalyst; or...

[0015] Industrially purified nitrogen gas is dried and then passed into a reactor to obtain ultrapure nitrogen gas. The reactor is filled with a bimetallic catalyst, which is prepared by the method described above for preparing a room-temperature catalytic bimetallic catalyst. The bimetallic catalyst provided by this invention exhibits good simultaneous removal of carbon monoxide and hydrogen. Attached Figure Description

[0016] The above and other objects, features, and advantages of the invention will become clearer through a more detailed description of the preferred embodiments illustrated in the accompanying drawings. The same reference numerals denote the same parts throughout the drawings, and the drawings are not intentionally drawn to scale with actual dimensions; the focus is on illustrating the gist of the invention.

[0017] Figure 1 This is a schematic diagram of the preparation process of ultrapure nitrogen provided by the present invention.

[0018] Figure 2 A process flow diagram of the gas purification method provided by the present invention. Detailed Implementation

[0019] The technical solution of the present invention will be further described in detail below with reference to specific embodiments, so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention.

[0020] This invention provides a method for preparing a room-temperature catalytic bimetallic catalyst, comprising the following steps: adding an oxidant to an aqueous solution of a metal salt and adjusting the pH; ultrasonically aging the coprecipitate for 20-40 minutes, aging it for 10-14 hours, obtaining a filter cake after filtration and washing, drying the filter cake overnight at 95℃-125℃, and then calcining it at 350℃-450℃ in an air atmosphere for 2-6 hours.

[0021] In a preferred embodiment, after calcination for 3-5 hours, the process further includes the following steps: using the calcined manganese dioxide catalyst as a support, ultrasonically impregnating it with 15-30% by mass of other metal salts, followed by drying and calcination at 380℃-420℃ to obtain a bimetallic catalyst. In a further preferred embodiment, ultrasonic impregnation is performed with 18-23% by mass of other metal salts.

[0022] In one embodiment, the metal salt in the aqueous solution is a manganese salt (e.g., manganese nitrate, manganese acetate), and the other metal salt is a copper salt, a silver salt, or a cobalt salt. For example, after calcination for 2-6 hours, a manganese dioxide catalyst is obtained. Using the manganese dioxide catalyst as a support, 15-30% by mass of copper nitrate, silver nitrate, or cobalt nitrate is ultrasonically impregnated to obtain supported bimetallic catalysts. This catalyst, under conditions of room temperature catalysis and short gas residence time, can achieve good simultaneous removal of carbon monoxide and hydrogen. The reaction times for both carbon monoxide and hydrogen are relatively long, with carbon monoxide permeation time exceeding 50 hours and hydrogen permeation time exceeding 8.8 hours, making it highly suitable for the long-cycle requirements of high-purity gas industrial production.

[0023] In one preferred embodiment, the aqueous metal salt solution contains copper and manganese in a molar ratio of (0.02-3):1. The solution is calcined in air for 3-5 hours to obtain a co-precipitated bimetallic catalyst. In this embodiment, the aqueous metal salt solution can be prepared from manganese acetate and copper acetate. The catalyst prepared by this method achieves its catalytic effect through the synergistic effect of copper and manganese. Even without using precious metals and with a relatively low copper proportion, it still exhibits good simultaneous catalytic effect on carbon monoxide and hydrogen, which is very significant. It has the advantage of low cost and is suitable for large-scale applications in the preparation of ultrapure gases.

[0024] The catalyst prepared in this invention uses an oxide of interacting Cu and Mn as the active component. Through the synergistic effect of the composite metal oxides based on these two metal elements, Cu and Mn oxides readily generate lattice distortions, and manganese oxides form more defects. These defects act as oxygen vacancies, thereby enhancing the ability to release or capture oxygen molecules. CuO, as the active site, receives lattice oxygen and active oxygen from MnO2, a transition metal, enhancing the catalytic oxidation activity of H2 and CO. This makes it not only effective at removing carbon monoxide but also usable as a catalyst for removing hydrogen. Furthermore, it can simultaneously catalyze the removal of both carbon monoxide and hydrogen from feed gases containing both impurities. Even for feed gases with a higher carbon monoxide concentration than hydrogen, it can effectively remove carbon monoxide while ensuring long-term catalytic removal of hydrogen.

[0025] In a preferred embodiment, the oxidant contains a supporting ion, which is one or more of H+, K+, Na+, Li+ and ammonium ions.

[0026] In a preferred embodiment, the oxidant includes one or more of potassium permanganate, hydrogen peroxide, sodium hypochlorite, ammonium pernitrate, and ammonium persulfate. In a more preferred embodiment, the oxidant is potassium permanganate.

[0027] In a preferred embodiment, the ultrasonic aging time is 25-35 minutes; the aging time is 11-13 hours; and the calcination temperature is 380℃-410℃.

[0028] refer to Figure 1 The present invention also provides a method for preparing ultrapure nitrogen gas, wherein air is compressed by an air compressor 11, dried and filtered by a drying and filtration device 12, and then introduced into a reactor 13. The gas flowing out of the reactor is then passed through a distillation device 14 to obtain ultrapure nitrogen gas. The reactor is filled with a bimetallic catalyst, which is prepared by the method for preparing a room temperature catalytic bimetallic catalyst as described in any embodiment.

[0029] refer to Figure 2 The present invention also provides a method for preparing ultrapure nitrogen gas, wherein industrial purified nitrogen gas 21 is dried by a drying and filtration device 22 and then passed into a reactor 23, and ultrapure nitrogen gas is obtained after passing through the reactor. The reactor is filled with a bimetallic catalyst, wherein the bimetallic catalyst is prepared by the method for preparing a room temperature catalytic bimetallic catalyst as described in any of the above embodiments.

[0030] The reactor referred to in this invention is a room temperature purification stationary reactor, which operates at 20℃-50℃.

[0031] The reactor referred to in this invention is a high-pressure intermittent static reactor, and the working pressure of the high-pressure intermittent static reactor is 0.2-50 bar.

[0032] To provide a better understanding of the technical solution of the present invention, several preferred embodiments are listed below for further detailed description.

[0033] Example 1:

[0034] Copper acetate and manganese acetate were mixed in a 3:1 molar ratio to prepare an aqueous solution of the metal salt. Potassium permanganate (potassium permanganate: manganese acetate molar ratio = 5:6) was added to the aqueous solution to adjust the pH to about 8. The coprecipitate was ultrasonically aged for 30 min, then stirred and aged at 30 °C for 12 h, filtered and washed to obtain a filter cake. The filter cake was dried overnight at 105 °C and then calcined at 400 °C in an air atmosphere for 4 h to obtain a certain proportion of coprecipitated copper-manganese bimetallic catalyst.

[0035] Example 2

[0036] Copper acetate and manganese acetate were mixed in a molar ratio of 0.1:1 to prepare an aqueous solution of the metal salt. Potassium permanganate (potassium permanganate: manganese acetate molar ratio = 5:6) was added to the aqueous solution to adjust the pH to about 8. The coprecipitate was ultrasonically aged for 30 min, then stirred and aged at 30 °C for 12 h, filtered and washed to obtain a filter cake. The filter cake was dried overnight at 105 °C and then calcined at 400 °C in an air atmosphere for 4 h to obtain a certain proportion of coprecipitated copper-manganese bimetallic catalyst.

[0037] Example 3

[0038] Copper acetate and manganese acetate were mixed in a molar ratio of 0.02:1 to prepare an aqueous solution of the metal salt. Potassium permanganate (potassium permanganate: manganese acetate molar ratio = 5:6) was added to the aqueous solution to adjust the pH to about 8. The coprecipitate was ultrasonically aged for 30 min, aged at 30 °C for 12 h, filtered and washed to obtain a filter cake. The filter cake was dried overnight at 105 °C and then calcined at 400 °C in an air atmosphere for 4 h to obtain a certain proportion of coprecipitated copper-manganese bimetallic catalyst.

[0039] Example 4

[0040] Manganese acetate was prepared into an aqueous solution, potassium permanganate was added to the aqueous solution to adjust the pH to about 8, the coprecipitate was ultrasonically aged for 30 min, aged at 30 °C for 12 h, filtered and washed to obtain a filter cake, the filter cake was dried at 105 °C overnight, and then calcined at 400 °C in an air atmosphere for 4 h to obtain MnO2. Then, this catalyst was used as a support and ultrasonically impregnated with 20% by mass of copper nitrate (that is, 100 parts of manganese dioxide, 20 parts of copper nitrate, and 20% copper nitrate). After drying and calcination at 400 °C, a 20% CuO-MnO2 supported bimetallic catalyst was obtained.

[0041] Example 5

[0042] Manganese acetate was prepared into an aqueous solution, potassium permanganate was added to the aqueous solution to adjust the pH to about 8, and the solution was aged at 30°C for 12 hours, filtered and washed to obtain a filter cake. The filter cake was dried overnight at 105°C and then calcined at 400°C in an air atmosphere for 4 hours to obtain MnO2. This catalyst was then used as a support and ultrasonically impregnated with 20% by mass of silver nitrate (that is, 100 parts of manganese dioxide, 20 parts of silver nitrate, and 20% silver nitrate). After drying and calcination at 400°C, a 20% Ag-MnO2 supported bimetallic catalyst was obtained.

[0043] Example 6

[0044] Manganese acetate was prepared into an aqueous solution, potassium permanganate was added to the aqueous solution to adjust the pH to about 8, and the solution was aged at 30°C for 12 hours, filtered and washed to obtain a filter cake. The filter cake was dried overnight at 105°C and then calcined at 400°C in an air atmosphere for 4 hours to obtain α-MnO2. This catalyst was then used as a support and ultrasonically impregnated with 20% by mass of cobalt nitrate (that is, 100 parts manganese dioxide, 20 parts cobalt nitrate, and 20% cobalt nitrate). After drying and calcination at 400°C, a 20% Co-MnO2 supported bimetallic catalyst was obtained.

[0045] Comparative Example 1

[0046] Unlike Example 2, the oxidant in Comparative Example 1 was replaced with a tetramethylhydroxylamine solution (tetramethylhydroxylamine: manganese acetate molar ratio = 5:6), and the rest of the preparation methods were the same as in Example 2.

[0047] Comparative Example 2

[0048] Unlike Example 2, in Comparative Example 2, manganese acetate was replaced with cerium nitrate, while the rest of the preparation methods were the same as in Example 2.

[0049] Comparative Example 3

[0050] Copper acetate and manganese acetate were mixed in a molar ratio of 0.02:1 to prepare an aqueous solution. Potassium permanganate was added to this solution to adjust the pH to approximately 8. The solution was then directly filtered and washed to obtain a filter cake. The filter cake was dried overnight at 105°C, and then... 150℃ Calcination in an air atmosphere for 4 hours yielded

[0051] Comparative Example 4

[0052] Copper acetate and manganese acetate were mixed in a molar ratio of 0.02:1 to prepare an aqueous solution. Potassium permanganate was added to the aqueous solution to adjust the pH to approximately 8. The co-precipitate was ultrasonically aged for 30 minutes, then directly filtered and washed to obtain a filter cake. The filter cake was dried overnight at 105°C, and then... 150℃ The catalyst was obtained by calcination in an air atmosphere for 4 hours.

[0053] Comparative Example 5

[0054] Copper acetate and manganese acetate were mixed in a molar ratio of 0.02:1 to prepare an aqueous solution. Potassium permanganate was added to the aqueous solution to adjust the pH to approximately 8. The co-precipitate was then ultrasonically aged for 30 minutes. 48 hours of aging The filter cake was obtained, dried overnight at 105°C, and then calcined at 650°C in an air atmosphere for 4 hours to obtain the catalyst.

[0055] Comparative Example 6

[0056] Copper acetate and manganese acetate were mixed in a 4:1 molar ratio to prepare an aqueous solution. Potassium permanganate was added to the aqueous solution to adjust the pH to about 8. The coprecipitate was ultrasonically aged for 30 min, then stirred and aged at 30 °C for 12 h, filtered and washed to obtain a filter cake. The filter cake was dried overnight at 105 °C and then calcined at 400 °C in an air atmosphere for 30 h to obtain the catalyst.

[0057] Comparative Example 7

[0058] Powdered CuMnOx was synthesized using a sol-gel combustion-assisted method, with a copper to manganese molar ratio of 1 / 10. The required amounts of magnesium acetate hydrate, copper acetate hydrate, manganese acetate hydrate, and citric acid monohydrate were dissolved in deionized water. The molar ratios of citric acid to the metals (copper and manganese) were fixed at 2 and 60, respectively.

[0059] Next, the solution was stirred in an oil bath at 80°C for 5 hours and dried at 90°C for 2 hours. The dried sample was ground and sieved to obtain samples with a specific diameter range. Then, the sample was dried overnight at 110°C to obtain powder or spherical particle morphology, depending on the type and composition of the precursor metal. Finally, the obtained sample was calcined in a 21% oxygen (nitrogen balance, hereinafter referred to as air) stream, with the temperature increased to 450°C at a heating rate of 1°C per minute and held for 10 hours to obtain the catalyst.

[0060] Example of effect

[0061] (1) At room temperature (25°C) and atmospheric pressure, the catalysts prepared in Examples 1-6 and Comparative Examples 1-7 were pretreated at 290°C in flowing dry air for 45 min and then cooled to room temperature. This ensured that the catalyst surface was clean, dry, and in a consistent initial state, avoiding the influence of previously adsorbed moisture or other gases on the experimental results. The treated catalysts from different examples and comparative examples were respectively packed into a fixed-bed reactor, with a catalyst dosage of 0.2 g. The equilibrium gas was air, with air containing 2 ppmvH2 and 10 ppmvCO used as the feed gas, and a mass hourly space velocity (MHSV) of 4000 h⁻¹. -1 The residence time of the feed gas in the reactor is 0.3 seconds, and the CO / H2 concentration at the outlet is detected using helium ion chromatography. Here, "time" refers to the time span from the start of the feed gas flow into the reactor, measuring the CO / H2 content at the outlet of the reaction tube. The time span from when CO / H2 is detected at the outlet of the reaction tube is the CO / H2 breakthrough time. The CO / H2 content is detected using helium ion chromatography. The carbon monoxide breakthrough time and hydrogen breakthrough time measured for different catalysts are shown in Table 1.

[0062] Table 1

[0063]

[0064] As can be seen from the data in Table 1, the catalysts prepared in Examples 1-6 of this invention exhibit strong catalytic activity, capable of simultaneously removing 2 ppm H2 and 10 ppm CO at room temperature, maintaining 100% H2 conversion for 4-15 hours and CO conversion for over 50 hours. The catalytic activity is long-lasting, with a very long effective operating time, meeting the long-cycle operation requirements of industrial production. In particular, the catalyst prepared in Example 2 achieves H2 conversion for 8 hours while maintaining a CO conversion rate greater than 50 hours, demonstrating remarkable effectiveness.

[0065] In Comparative Example 1, the oxidant was replaced with tetramethylhydroxylamine solution instead of potassium permanganate. Since no suitable supporting ion was selected, the overall catalytic activity was relatively poor.

[0066] In Comparative Example 2, cerium nitrate and copper acetate were used to prepare the catalyst. Since the two did not have a synergistic effect, the catalyst activity of the catalyst was relatively poor.

[0067] In Comparative Example 3, the catalyst did not undergo ultrasonic aging and stirring aging, resulting in very low catalyst activity and difficulty in achieving CO and H2 removal. This indicates that ultrasonic aging and stirring aging have a significant impact on catalyst activity.

[0068] In Comparative Example 4, there was no aging and stirring step, and the calcination temperature was only 150℃. The catalyst activity was very low, indicating that the calcination temperature was too low and had a significant impact on the catalyst activity.

[0069] In Comparative Example 5, the aging time was as long as 45 hours and the calcination temperature was as high as 650℃. The catalyst activity was very low, indicating that both excessive aging time and excessively high calcination temperature will reduce the performance of the catalyst.

[0070] In Comparative Example 6, the ratio of copper acetate to manganese acetate was 4:1, which exceeded the range of the present invention. The catalyst activity was very low, indicating that an unreasonable ratio of copper to manganese will reduce the catalyst activity.

[0071] Comparative Example 7 used the gelation method to prepare the catalyst, and the prepared catalyst had very low activity.

[0072] In summary, the preparation method provided by this invention is reasonable, and the catalyst obtained can simultaneously catalytically remove low concentrations of hydrogen and carbon monoxide at room temperature, making it suitable for the purification of ultrapure nitrogen. High-purity nitrogen is mainly obtained through cryogenic distillation, but this method often results in the presence of low concentrations of carbon monoxide and hydrogen as permanent impurities, which are difficult to remove. The catalyst prepared by this invention can simultaneously catalytically remove low concentrations of hydrogen and carbon monoxide at room temperature, and it can ensure a long effective reaction time for both hydrogen and carbon monoxide. This makes it suitable for the long-cycle operation requirements of industrial ultrapure nitrogen purification, meeting the requirements for industrial ultrapure nitrogen purification and providing sufficient pure ultrapure nitrogen for the fabrication of advanced node wafers below 7nm.

[0073] (2) The catalyst (0.2g) prepared in Examples 1-3 was filled into a batch reactor. The reactor was operated at 20℃-50℃ and statically removed 10ppmv CO and 2ppmv H2 at 5bar pressure. The test results are shown in Table 2.

[0074] Table 2

[0075]

[0076] As shown in Table 2, when the catalyst prepared by the method of this invention is used to remove impurities under intermittent pressurized conditions at room temperature, with the introduction of 10 ppm CO and 2 ppm H2, the carbon monoxide concentration was detected to be 1.2 ppm-1.5 ppm and the hydrogen concentration to be 102 ppb-154 ppb after 5 minutes. This indicates that the impurity concentration has significantly decreased after 5 minutes, demonstrating that the catalyst is active and has begun to work, but has not yet completely purified the gas. At 20 minutes, the impurity concentration drops sharply, proving that the catalyst is continuously and effectively removing hydrogen and carbon monoxide simultaneously over time, with increasingly better purification results. At 30 minutes, the concentrations of hydrogen and carbon monoxide are less than 1 ppb. This demonstrates that the catalyst prepared by the method of this invention can simultaneously remove 100% of low concentrations of CO and H2 at room temperature. This provides a usable catalyst for the efficient and deep purification of high-purity industrial gases and even electronic-grade industrial gases.

[0077] (3) The catalyst (0.2 g) prepared in Examples 1-3 was placed in a stationary reactor, and air containing 400 ppmv H2 and 200 ppmv CO was used as feed gas, with a mass hourly space velocity of 4000 h⁻¹. -1The residence time of the feed gas in the reactor was 0.3 seconds. The CO / H2 concentration at the outlet was detected using helium ion chromatography. Here, "time" refers to the time span from the start of the feed gas flow into the reactor, detecting the H2 content at the outlet of the reaction tube, until CO / H2 is detected at the outlet of the reaction tube; this time span is the CO / H2 breakthrough time. The CO / H2 content was detected using helium ion chromatography. The test results are shown in Table 3.

[0078] Table 3

[0079]

[0080] As shown in Table 3, the catalyst prepared by the method of this invention can simultaneously ensure the permeation time of both carbon monoxide and hydrogen when the hydrogen concentration is higher than the carbon monoxide concentration, with the hydrogen permeation time reaching 0.8-1.1 hours. This indicates that the catalyst prepared by this invention can also ensure the simultaneous removal of hydrogen and carbon monoxide under conditions where the hydrogen concentration is higher than the carbon monoxide concentration, maintaining a hydrogen permeation time of 0.8-1.1 hours, which is a very significant effect.

[0081] (4) Place the catalyst (0.2 g) prepared in Examples 1-3 into a fixed-bed reactor. Introduce air containing 2 ppmv H2 and 200 ppmv CO at a space velocity of 4000 h⁻¹. -1 The residence time of the feed gas in the reactor was 0.3 seconds. The concentrations of H2 and CO at the outlet were detected using helium ion chromatography. Here, "time" refers to the time span from the start of the feed gas flow into the reactor, measuring the CO / H2 ratio at the outlet of the reaction tube. The time span from when CO / H2 is detected at the outlet of the reaction tube is the CO / H2 breakthrough time. The CO / H2 content was detected using helium ion chromatography. The measured carbon monoxide breakthrough time and hydrogen breakthrough time are shown in Table 4.

[0082] Table 4

[0083]

[0084] As shown in Table 4, under the conditions of 2 ppmvH2 and 200 ppmvCO as raw materials, it can not only ensure a long effective reaction time for carbon monoxide, but also remove low concentrations of hydrogen.

[0085] Generally, under conditions where the carbon monoxide concentration is significantly higher than the hydrogen concentration in the original gas, hydrogen removal is impossible due to competitive adsorption. However, when the catalyst prepared by the method of this invention is used to remove hydrogen from an original gas with a carbon monoxide concentration significantly higher than the hydrogen concentration, although the effective action time for hydrogen removal decreases, it still achieves an effective action time of 0.8-1.1 hours. This indicates that the catalyst prepared by this invention has good carbon monoxide tolerance and can still guarantee the simultaneous removal of carbon monoxide and hydrogen under harsh conditions of high carbon monoxide concentration, with a very significant effect on the simultaneous removal of both carbon monoxide and hydrogen.

[0086] (5) At room temperature (25°C) and normal pressure, the catalysts prepared in each example and comparative example were pretreated at 60°C in flowing dry air for 45 min, and then cooled to room temperature. The pretreated catalyst (0.2 g) was placed in a fixed-bed reactor, and feed gas containing different concentrations of H2 was introduced at a mass hourly space velocity (MSV) of 4000 h⁻¹. -1 The residence time of the feed gas in the reactor was 0.3 seconds, and the concentration of H2 at the outlet was detected using helium ion chromatography. Removal tests were conducted using different concentrations of H2 (50 ppb, 1 ppm, 2 ppm, 10 ppm, 400 ppm) as the feed gas, with dry air as the equilibrium gas. The removal effects of different embodiments and comparative examples on different concentrations of hydrogen were tested. Here, "time" refers to the time span from the start of the feed gas flow into the reaction tube, detecting the H2 content at the outlet of the reaction tube, until H2 is detected at the outlet of the reaction tube (limit of quantitation 20 ppb). This time span is the H2 breakthrough time. The results are shown in Table 5.

[0087] Table 5

[0088]

[0089] As shown in Table 5, the catalyst prepared in this embodiment of the invention exhibits a long hydrogen permeation time for hydrogen of different concentrations, enabling deep removal of hydrogen from a wide range of concentrations in the gas. The effective action time for removing 50 ppb of hydrogen is greater than 24 hours, allowing for continuous deep removal of low-concentration hydrogen (50 ppb) in industrial production. The catalyst prepared in Example 2 of this invention maintains a 100% hydrogen conversion rate for over 16 hours under conditions of room temperature, high space velocity, extremely short residence time, and feed gas concentration as low as 2 ppm, demonstrating excellent hydrogen catalytic activity and long-term operational stability. For the same material, the lower the hydrogen concentration, the longer the permeation time; as the concentration increases, the permeation time generally shortens. This is because at room temperature, H2 is converted to H2O and adsorbed on the active sites, gradually accumulating and occupying reaction sites. The catalyst prepared in this embodiment of the invention not only exhibits superior catalytic activity for removing low-concentration hydrogen and can remove hydrogen for extended periods, but also has a wide range of hydrogen concentrations that can be removed, and the catalyst exhibits good stability.

[0090] The preparation methods in Comparative Examples 1-7 are different from those in this invention. The catalysts prepared have poor hydrogen removal performance. On the one hand, they do not have a long effective time for removing low-concentration hydrogen. On the other hand, when the hydrogen concentration is ≥10ppm, the activity is basically lost. The concentration range of hydrogen that can be removed is narrow and cannot be applied to long-term and stable hydrogen removal in industrial production.

[0091] (6) The catalyst (0.2g) was statically removed in a batch reactor. H2 of different concentrations (50ppb, 1ppm, 2ppm, 10ppm, 400ppm) was introduced into the reactor and pressurized to 5 bar. The reaction was carried out for 2 hours. The gas in the reactor was sampled for component analysis. The results are shown in Table 6.

[0092] Table 6

[0093]

[0094] As shown in Table 6, the catalysts prepared by the methods in Examples 1-4 of this invention exhibit good removal effects for hydrogen concentrations of 50 ppb, 1 ppm, 2 ppm, 10 ppm, and 400 ppm. After two hours of reaction, the hydrogen concentration can be reduced to <1 ppb, achieving deep removal of hydrogen over a wide range of concentrations, meeting the requirements of industrial production. The preparation methods in Comparative Examples 1-6 differ from those of this invention, and the catalysts obtained from these methods show poor hydrogen removal effects. For hydrogen concentrations of 1 ppm and above, good removal effects are difficult to achieve after two hours of reaction. This indicates that the catalysts prepared by the method provided by this invention can achieve good removal effects for hydrogen concentrations from 50 ppb to 400 ppm.

[0095] (7) At room temperature (25°C) and normal pressure, the catalysts prepared in each example and comparative example were pretreated at 60°C in flowing dry air for 45 min, and then cooled to room temperature. The pretreated catalyst (0.2 g) was placed in a fixed-bed reactor, and air containing different concentrations of carbon monoxide was introduced at a mass hourly space velocity (HHSV) of 4000 h⁻¹. -1 The residence time of the feed gas in the reactor was 0.3 seconds. Tests were conducted using different concentrations of CO (50 ppb, 10 ppm, 400 ppm, 1% CO, and 10% CO) (with dry air as the equilibrium gas) as feed gas to test the removal efficiency of different embodiments and comparative examples. The CO concentration at the outlet was detected using helium ion chromatography. "Time" refers to the CO breakthrough time, measured from the start of the feed gas flow into the reaction tube until CO was detected at the outlet (limit of quantitation 20 ppb). The test results are shown in Table 7.

[0096] Table 7

[0097]

[0098] As shown in Table 7, the catalysts prepared by the methods in Examples 1-6 of this invention exhibit good removal effects on carbon monoxide concentrations of 20 ppb, 10 ppm, and 400 ppm, with longer reaction times and permeation times exceeding 50 hours. Furthermore, under conditions of 1% CO concentration, the catalysts prepared in these examples can maintain 100% CO conversion for 1.2-2 hours, and the permeation time for 10% CO is 0.6-1.1 hours. This indicates that the catalysts prepared by the methods of this invention not only possess deep removal capabilities for low-concentration carbon monoxide but also maintain a certain reaction time even at higher carbon monoxide concentrations, demonstrating good tolerance. They exhibit excellent catalytic activity and stability, achieving efficient room-temperature removal of CO from ultrapure gases over a wide concentration range, and can be applied to long-cycle carbon monoxide removal in industrial production.

[0099] The preparation methods in Comparative Examples 1-6 are different from those of the present invention. The catalysts prepared by these examples have a shorter effective time for deep removal of low concentrations of carbon monoxide and do not have the ability to withstand the removal of high concentrations of carbon monoxide.

[0100] (8) The catalyst (0.2 g) prepared in the examples and comparative examples was placed in a batch reactor for static removal. The reactor was pressurized to 10 bar and the reaction was carried out for 1 h. The gas in the reactor was sampled for component analysis, and the results are shown in Table 8.

[0101] Table 8

[0102]

[0103] As can be seen from the data in Table 8, the catalysts prepared by the methods in Examples 1-6 of this invention can achieve efficient removal of carbon monoxide from ultrapure gas to below 1 ppb at room temperature under a wide range of carbon monoxide concentrations. The preparation methods of Comparative Examples 1-6 differ from those of this invention, and the catalysts obtained from these examples do not exhibit good carbon monoxide removal performance. This indicates that the preparation method of this invention is reasonable, and the catalysts prepared under room temperature and static pressure conditions can reduce the concentration of these CO impurities to below 1 ppb after 2 hours of reaction, meeting the purification requirements for industrial production.

[0104] In summary, it can be seen that the catalysts prepared in Examples 1-6 all exhibit good removal effects of hydrogen and carbon monoxide, with long effective action times and excellent performance. The co-precipitated copper-manganese catalysts prepared in Examples 1-3 do not contain precious or rare metals, and while maintaining low cost, they also achieve very good removal effects of carbon monoxide and hydrogen, demonstrating significant results. The supported catalysts prepared in Examples 4-6, when simultaneously removing carbon monoxide and hydrogen, show an effective action time of more than 8 hours for hydrogen, even reaching 15 hours, demonstrating remarkable performance.

[0105] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for preparing a room temperature catalytic bimetallic catalyst, characterized by, The method comprises the following steps: adding an oxidizing agent into a metal salt aqueous solution and adjusting pH; aging the co-precipitate under ultrasonic for 20-40 minutes, aging for 10-14 hours, obtaining a filter cake after filtration and washing, drying the filter cake at 95-125 ℃ overnight, and then calcining the filter cake at 350-450 ℃ under an air atmosphere for 2-6 hours.

2. The method for preparing a room-temperature bimetallic catalyst as described in claim 1, characterized in that, The calcining step further comprises the following steps: The oxide catalyst obtained after calcining is used as a carrier to ultrasonically immerse 15-30% of other metal salts by mass fraction, and then a bimetallic catalyst is obtained after drying and calcining at 380-420 ℃.

3. The preparation method of the room temperature catalytic bimetallic catalyst according to claim 2, characterized in that, The metal salt in the metal salt aqueous solution is a manganese salt, the oxide obtained after calcining is manganese dioxide, and the other metal salt is a metal salt of copper, silver or cobalt.

4. The method for preparing a room-temperature bimetallic catalyst as described in claim 2, characterized in that, The other metal salt is ultrasonically immersed at a mass fraction of 18-23%.

5. The preparation method of the room temperature catalytic bimetallic catalyst according to claim 1, characterized in that, The metal salt aqueous solution contains copper and manganese, and the molar ratio of copper to manganese is (0.02-3):1, and a bimetallic catalyst is obtained after calcining under an air atmosphere for 3-5 hours.

6. The preparation method of the room temperature catalytic bimetallic catalyst according to claim 5, characterized in that, The metal salt aqueous solution is prepared from manganese acetate and copper acetate.

7. The method for preparing a room-temperature bimetallic catalyst as described in claim 1, characterized in that, The ultrasonic aging time is 25-35 minutes, and the aging time is 11-13 hours.

8. The method for preparing a room-temperature bimetallic catalyst as described in claim 1, characterized in that, The calcining temperature is 380-410 ℃.

9. The method for preparing a room-temperature bimetallic catalyst as described in claim 1, characterized in that, The oxidizing agent contains a supporting ion which is one or more of H + , K + , Na + , Li + , and an ammonium ion.

10. A method of producing ultra-pure nitrogen gas, characterized by, Air is compressed, dried and filtered, and then introduced into a reactor, and the gas flowing out of the reactor after passing through the reactor is refined to obtain ultra-pure nitrogen, the reactor is filled with a bimetallic catalyst, and the bimetallic catalyst is prepared by the method for preparing a room-temperature catalytic bimetallic catalyst according to any one of claims 1-9; or, Industrial purified nitrogen is introduced into a reactor after drying, and ultra-pure nitrogen is obtained after passing through the reactor, the reactor is filled with a bimetallic catalyst, and the bimetallic catalyst is prepared by the method for preparing a room-temperature catalytic bimetallic catalyst according to any one of claims 1-9.

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