A catalyst and a method of preparation

Abstract

The application discloses a catalyst and a preparation method, relates to the technical field of catalyst synthesis, and aims at solving the problem that existing catalysts are easy to be deactivated under low temperature, high temperature and high humidity conditions. The catalyst is a zeolite molecular sieve catalyst with an AEI configuration, the zeolite molecular sieve catalyst contains copper ions introduced into the zeolite molecular sieve catalyst in the form of a copper source, and the amount of medium-strong acid in the zeolite molecular sieve catalyst accounts for 50-70% of the total acid amount. The preparation method is used for preparing the catalyst. The catalyst and the preparation method provided by the application are used for improving the activity and service life of the catalyst.

Description

Technical Field

[0001] This invention relates to the field of catalyst synthesis technology, and in particular to a catalyst and its preparation method. Background Technology

[0002] Environmental issues have become a hot topic in society, with nitrogen oxides (NOx) posing an increasingly significant threat to the environment. NOx sources can be categorized into natural and anthropogenic sources. Anthropogenic emissions are mainly divided into stationary and mobile sources. In mobile source denitrification, ammonia selective catalytic reduction (NH3-SCR) technology for eliminating NOx has become the most promising and widely used denitrification technology due to its high efficiency and low cost.

[0003] In NH3-SCR technology, WO3 or MoO3-supported V2O5-TiO2 catalysts are used as the main catalysts for denitrification. With increasingly stringent emission standards, particulate filters must be installed before the Selective Catalytic Reduction (SCR) system in diesel vehicle exhaust aftertreatment systems meeting China VI emission standards. However, the regeneration of the particulate filter generates a high-temperature and high-humidity environment, which can affect the catalytic performance of SCR. Therefore, developing catalysts that simultaneously possess high activity and high-temperature hydrothermal stability is particularly important. Summary of the Invention

[0004] The purpose of this invention is to provide a catalyst and its preparation method. This catalyst not only has good stability and high catalytic activity under low and high temperature conditions, but also maintains good hydrothermal stability under high humidity conditions.

[0005] In a first aspect, the present invention provides the following technical solution:

[0006] A catalyst, which is an AEI-configured zeolite molecular sieve catalyst, contains copper ions introduced into the zeolite molecular sieve catalyst in the form of a copper source, wherein the amount of medium-strong acid in the zeolite molecular sieve catalyst accounts for 50%-70% of the total acid amount, preferably 55-65%.

[0007] Compared with existing technologies, the catalyst provided by this invention is an AEI-configured zeolite molecular sieve catalyst. This zeolite molecular sieve catalyst contains copper ions introduced into the catalyst in the form of a copper source. Since the copper ions are introduced in the form of a copper source, they can be uniformly dispersed on the framework of the zeolite molecular sieve catalyst, avoiding CuO agglomeration, thereby enhancing the metal active sites of the zeolite molecular sieve catalyst and making the catalyst more active. Simultaneously, the zeolite molecular sieve catalyst of this invention has a medium-strong acid content of 50%-70% of the total acid content. Under the medium-strong acid content and total acid content conditions of this invention, the zeolite molecular sieve catalyst has a large specific surface area. Since a larger specific surface area means more active sites on the catalyst surface, it is easier to activate reactant molecules, thereby improving the reactivity of the zeolite molecular sieve catalyst.

[0008] Meanwhile, during the denitrification reaction, the zeolite molecular sieve catalyst of the present invention can avoid the problems of catalyst deactivation, aging and short life when the amount of medium-strong acid is too large, thereby maintaining the zeolite molecular sieve catalyst with high catalytic activity and long catalytic life.

[0009] Secondly, the present invention also provides a method for preparing a catalyst, comprising:

[0010] Step 200: Using Cu-NaY molecular sieve, silicon source, alkaline solution, organic template agent and deionized water as raw materials, Cu-SSZ-39 molecular sieve is prepared; the copper ions contained in the Cu-NaY molecular sieve are introduced into the Y-type molecular sieve framework in the form of copper source;

[0011] Step 300: Prepare Cu-SSZ-39 molecular sieve catalyst.

[0012] Compared with the prior art, the beneficial effects of the catalyst preparation method provided by the present invention are the same as those of the catalyst in the first aspect, and will not be repeated here. Attached Figure Description

[0013] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0014] Figure 1 A flowchart illustrating the preparation process of the catalyst provided by this invention;

[0015] Figure 2 A flowchart illustrating the preparation process of Cu-NaY molecular sieves provided by this invention;

[0016] Figure 3 A flowchart illustrating the preparation process of the Cu-SSZ-39 molecular sieve provided by this invention;

[0017] Figure 4 These are XRD comparison images of Embodiment 2 and Comparative Example 2 of the present invention;

[0018] Figure 5 This is a SEM image of the catalyst in Example 2 of the present invention;

[0019] Figure 6 This is a comparison diagram of H2-TPR between Embodiment 2 and Comparative Example 2 of the present invention; Detailed Implementation

[0020] To make the technical problems, solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0021] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. "Several" means one or more, unless otherwise explicitly specified.

[0022] This invention provides a catalyst for removing nitrogen oxides in a selective catalytic reduction (SCR) aftertreatment system. The catalyst is an AEI-type zeolite molecular sieve catalyst containing copper ions introduced as a copper source. The total acidity of the zeolite molecular sieve catalyst is greater than 60 Acm. 2 g -1 The medium-strong acid content of the zeolite molecular sieve catalyst accounts for 50%-70% of the total acid content, for example: 57%, 59%, 62%, 66%. It should be understood that this total acid content can be defined as the acid content of the zeolite molecular sieve catalyst at 200℃, and the medium-strong acid content can be defined as the acid content of the zeolite molecular sieve catalyst at 350℃. The acid content can be defined as the sum of Brønsted acid and Lewis acid.

[0023] The catalyst provided in this invention is an AEI-configured zeolite molecular sieve catalyst. This zeolite molecular sieve catalyst contains copper ions introduced into the catalyst in the form of a copper source. Since the copper ions are introduced in the form of a copper source, they can be uniformly dispersed on the framework of the zeolite molecular sieve catalyst, avoiding CuO agglomeration, thereby enhancing the metal active sites of the zeolite molecular sieve catalyst and making the catalyst more active. Simultaneously, the total acid content of the zeolite molecular sieve catalyst of this invention, with the medium-strong acid content accounting for 50%-70% of the total acid content, preferably 55-65%, provides a large specific surface area. A larger specific surface area results in more active sites on the catalyst surface, making it easier to activate reactant molecules and thus improving the reactivity of the zeolite molecular sieve catalyst.

[0024] In addition, during the denitrification reaction, the zeolite molecular sieve catalyst of the present invention can avoid the problems of catalyst deactivation, aging and short life when the amount of medium-strong acid is too large, thereby maintaining the zeolite molecular sieve catalyst with high catalytic activity and long catalytic life.

[0025] In one feasible embodiment, when the amount of moderately strong acid in the zeolite molecular sieve catalyst accounts for 50%-70% of the total acid content, the specific surface area of ​​the zeolite molecular sieve catalyst in this embodiment of the invention is 755 m². 2 / g~794m 2 / g, for example: 755m 2 / g、794m 2 / g or 771m 2 The relative crystallinity of the zeolite molecular sieve catalyst is 93%–102%, for example, 93%, 102%, or 98%; the silica-to-alumina ratio of the zeolite molecular sieve catalyst is (13–20):1, for example, 13.9:1, 17.1:1, or 14.8:1. Experiments have shown that, under the above-mentioned conditions of specific surface area, relative crystallinity, and silica-to-alumina ratio, the zeolite molecular sieve catalyst of this embodiment can achieve the required total acid content and medium-strong acid content. Therefore, under these conditions, the problems of catalyst deactivation, aging, and short lifespan caused by excessive medium-strong acid content can be avoided, thus maintaining the zeolite molecular sieve catalyst with high catalytic activity and a long catalytic lifespan.

[0026] Furthermore, specific surface area and relative crystallinity have a certain influence on zeolite molecular sieve catalysts. A larger specific surface area and higher relative crystallinity result in more active sites on the catalyst surface, making it easier to activate reactant molecules and thus improving the reactivity of the zeolite molecular sieve catalyst. Therefore, under the specific surface area and relative crystallinity conditions of the zeolite molecular sieve catalyst in this embodiment of the invention, the reactivity of the zeolite molecular sieve catalyst can be improved. Moreover, under the silicon-to-aluminum ratio of this invention, after the crystallization reaction, the silicon in the silicon source and the aluminum in the aluminum source can be linked together through oxygen bonds, and there is essentially no free aluminum source present.

[0027] In one possible implementation, the zeolite molecular sieve catalyst of this embodiment contains 0.1% to 10% copper ions by mass. Experiments have shown that at the aforementioned copper ion content, the zeolite molecular sieve catalyst of this embodiment exhibits better catalytic activity and better high- and low-temperature stability.

[0028] For the aluminum source, it can be at least one of boehmite, sodium aluminate, aluminum sulfate, aluminum nitrate, and aluminum chloride. For the silicon source, it can be at least one of water glass, silica sol, silica, tetramethyl orthosilicate, tetraethyl orthosilicate, tetrapropyl orthosilicate, and tetrabutyl orthosilicate. For the copper source, it can be at least one of copper acetate, copper sulfate, copper nitrate, and copper hydroxide.

[0029] This invention also provides a method for preparing a catalyst, which can be used to prepare the catalyst of this invention. Figure 1 A flowchart illustrating the preparation process of the catalyst provided by this invention is shown, as follows: Figure 1 As shown, the preparation method of this catalyst includes:

[0030] Step 200: Using Cu-NaY molecular sieve, silicon source, alkaline solution, organic template agent and deionized water as raw materials, Cu-SSZ-39 molecular sieve is prepared. The copper ions contained in Cu-NaY molecular sieve are introduced in the form of copper source.

[0031] Step 300: Prepare Cu-SSZ-39 molecular sieve catalyst.

[0032] For example, Cu-SSZ-39 molecular sieve is subjected to ammonium exchange and hydrothermal treatment, and then pressed and sieved to produce Cu-SSZ-39 type molecular sieve catalyst.

[0033] In one alternative approach, Figure 2 The preparation flow chart of the Cu-NaY molecular sieve provided by the present invention is shown, as follows: Figure 2 As shown, the preparation method of Cu-NaY molecular sieve may include:

[0034] Step 101: Mix silicon source, aluminum source, copper source, alkaline solution and water and then age the mixture to produce a crystallization guiding agent.

[0035] For example, in an embodiment of the present invention, copper source, silicon source, aluminum source, alkaline solution, and water are added in a certain ratio, stirred evenly, and then the reaction mixture is stirred and aged at 0℃~80℃ for 1~50h, preferably at 15℃~65℃ for 2h~20h, to obtain a crystallization guiding agent containing copper ions. For example, when the crystallization guiding agent of the embodiment of the present invention is calculated as a mixture of copper oxide, sodium oxide, aluminum oxide, silicon dioxide, and water, the crystallization guiding agent is added in a molar ratio of CuO:Na2O:Al2O3:SiO2:H2O of (0.01~0.5):(8~30):1:(8~30):(150~450), preferably in a molar ratio of (0.1~0.5):(10~20):1:(10~20):(200~400) to prepare the crystallization guiding agent. Since the copper ions in the crystallization guide agent of this embodiment are introduced through a copper source, the copper ions can be uniformly dispersed on the framework of the zeolite molecular sieve catalyst, avoiding CuO agglomeration, thereby enhancing the metal active sites of the zeolite molecular sieve catalyst and making the zeolite molecular sieve catalyst more active.

[0036] For alkaline solutions, they can be one or more of the following: sodium aluminate, sodium hydroxide solution, ammonia, potassium hydroxide solution, and sodium bicarbonate solution.

[0037] For organic template agents, they can be at least one of N,N-dimethyl-N,N-bicyclononane, 2,2,6,6-tetramethyl-N,N-dimethylpiperidine, N-cyclooctyl-pyridine, 2,2,6,6-tetramethyl-N-ethylpiperidine, 2-ethyl-N,N-dimethylpiperidine, 3,5-dimethyl-N,N-dimethylpiperidine, tetrapropylammonium hydroxide (POH), tetrapropylammonium bromide (IPBr), tetraethylammonium hydroxide (EOH), tetraethylammonium bromide (EBr), triethylamine (E3N), or ethylenediamine (E2N).

[0038] The present invention uses the above-mentioned organic template agent as the template agent for the crystallization reaction. The molecular size of such organic template agents is moderate, and they can play a structural guiding and filling role in the synthesis of Cu-SSZ-39 molecular sieve. In addition, such organic template agents are all charged in aqueous solution, and play a charge filling role in the synthesis of Cu-SSZ-39 molecular sieve.

[0039] Step 102: Add crystallization guide agent, alkali solution and water to silicon source and stir for 1h to 20h. Then add aluminum source and copper source in sequence, and then carry out gelation reaction to obtain the first gel mixture.

[0040] For example, at 10℃ to 80℃, a crystallization guide containing copper ions, an alkaline solution, and water are added to a silicon source and stirred for 1h to 20h, preferably 2-10h. An aluminum source is then added and stirred until homogeneous. Finally, a copper source is added and the mixture is aged for 0.5h to 15h to obtain a first gel mixture. For example, when the first gel mixture of this embodiment is calculated as a mixture of copper oxide, sodium oxide, aluminum oxide, silicon dioxide, and water, the molar ratio of CuO:Na2O:Al2O3:SiO2:H2O in the first gel mixture is (0.01~0.5):(1~6):1:(8~30):(100~350).

[0041] The first gel mixture of the present invention contains a crystallization guiding agent with a mass content of 1% to 50%, preferably 3% to 25%, and the pH value of the first gel mixture is controlled between 11.0 and 13.5. Under the content of the crystallization guiding agent in the present invention, the pH value of the first gel mixture can be directly controlled within a reasonable range, so that there is no need to add an additional acid solution to adjust the pH value.

[0042] Step 103: Crystallize the first gel mixture to obtain Cu-NaY molecular sieve.

[0043] For example, the first gel mixture is statically crystallized at a temperature of 80℃ to 140℃ for 24h to 140h. Preferably, the crystallization temperature is 85℃ to 120℃ and the crystallization time is 30h to 100h. After crystallization, the mixture is centrifuged, washed, and dried to obtain Cu-NaY molecular sieve.

[0044] In one alternative method, Cu-SSZ-39 molecular sieve is prepared using Cu-NaY molecular sieve, silicon source, alkaline solution, organic template agent, and deionized water as raw materials. Figure 3 The preparation flow chart of the Cu-SSZ-39 molecular sieve provided by the present invention is shown, as follows: Figure 3 As shown, it includes the following steps:

[0045] Step 201: Mix Cu-NaY molecular sieve, silicon source, alkaline solution, organic template agent and deionized water, and then carry out a gelation reaction to obtain a second gel mixture.

[0046] For example, when the second gel mixture is calculated as a mixture of copper oxide, sodium oxide, aluminum oxide, silicon dioxide, water and organic template agent, the molar ratio of copper oxide, sodium oxide, aluminum oxide, silicon dioxide, water and organic template agent in the second gel mixture is (0.01-0.5):(5-50):1:(10-100):(500-1000):(5-20), preferably (0.05-0.2):(5-20):1:(10-30):(600-800):(5-10).

[0047] Step 202: Crystallize the second gel mixture and then calcine it to obtain Cu-SSZ-39 molecular sieve.

[0048] For example, in this embodiment of the invention, the second gel mixture is dynamically crystallized at 100℃ to 180℃ for 24 to 80 hours, and then calcined at 300℃ to 700℃ for 1 to 10 hours to obtain Cu-SSZ-39 molecular sieve. The calcination rate is 1℃ / min to 30℃ / min, preferably, the rate of heating to the calcination temperature is 3℃ / min to 8℃ / min. If the calcination rate of the molecular sieve is too fast, it will lead to varying degrees of damage to the molecular sieve structure, reducing its crystallinity and thus affecting the adsorption and activity of the molecular sieve. At the calcination rate of the second gel mixture in this embodiment of the invention, the molecular sieve structure can be preserved without damage, and the crystallinity can be maintained well, thereby improving the adsorption and activity of the molecular sieve.

[0049] In one alternative method, the above-mentioned ammonium exchange process can be as follows: the above-mentioned Cu-SSZ-39 molecular sieve is mixed with an ammonium salt solution for ammonium ion exchange. During the exchange process, an acidic solution is added to adjust the pH value of the mixture to the range of 2.0-6.0. At the same time, the mixture is slurried according to the mass ratio of molecular sieve (dry basis): ammonium salt: water = 1:(0.5-2):(5-20), and stirred for 0.5h-5h at 10℃-100℃.

[0050] It should be understood that the ammonium salt used in the ammonium exchange process can be selected from one or a mixture of several of ammonium sulfate, ammonium chloride, ammonium nitrate, ammonium acetate, ammonium oxalate, and ammonium phosphate. The acidic solution used to adjust the pH of the system in the ammonium exchange process can be selected from one or a mixture of several of aqueous solutions of hydrochloric acid, sulfuric acid, nitric acid, acetic acid, oxalic acid, and carbonic acid.

[0051] For example, the above-mentioned hydrothermal treatment process can be as follows: the molecular sieve that has undergone ammonium exchange treatment is placed in a hydrothermal furnace at 400℃-850℃ and calcined in a 5%-100% (volume) water vapor atmosphere for 0.5h-100h. Preferably, the hydrothermal treatment temperature is 500℃-800℃, the water vapor volume is 7%-50%, and the calcination time is 20h-60h.

[0052] To verify the effectiveness of the catalyst provided in the embodiments of the present invention, the embodiments of the present invention are demonstrated by comparing the embodiments with comparative examples.

[0053] In the following examples and comparative examples, the sample characterization methods are as follows:

[0054] XRD characterization was performed using a Shimadzu X-ray powder diffractometer from Japan. The test conditions were: CuKα radiation, Ni filter, tube voltage 30 kV, tube current 40 mA, step width 0.02, scanning range 5-35°, and scanning rate 5° / min.

[0055] The relative crystallinity Xi of a molecular sieve is calculated as follows: Xi = ∑Ai / ∑AR;

[0056] ∑Ai represents the sum of the XRD peak areas of the test sample, and ∑AR represents the sum of the XRD peak areas of the reference sample, which is SSZ-39 molecular sieve purchased from the market. In the following examples and comparative examples, SSZ-39 molecular sieve products manufactured by Zhongchumei Co., Ltd. are used as reference samples.

[0057] BET characterization was performed using a Physico ipore 600 analyzer. The pore volume of the molecular sieve was determined using the low-temperature nitrogen adsorption method, according to the RIPP 151-90 standard method (《Petrochemical Analytical Methods (RIPP Test Methods)》, edited by Yang Cuiding et al., Science Press, 1990). The total pore volume of the molecular sieve was determined based on the adsorption isotherm, and then the micropore volume of the molecular sieve was determined from the adsorption isotherm using the T-plot method. The specific surface area was calculated using the BET method.

[0058] Infrared spectroscopy (IR): The type of acid sites on the sample surface was determined by pyridine adsorption-desorption infrared spectroscopy under high vacuum conditions. The instrument was a Nicolet 870 Fourier transform infrared spectrometer. Measurement method: 8–10 mg / cm³ of... -2 Cu-SSZ-39 molecular sieve powder samples were pressed into thin sheets and first subjected to 623 K, 1×10⁻⁶ -3 After pretreatment at Pa for 4 h, the sample was cooled to room temperature, and the infrared spectrum of the hydroxyl region was scanned. After pyridine adsorption at room temperature, the temperature was then raised to the measurement temperature (200℃, 350℃), and the sample was subjected to 10... -4 Desorption was performed at Pa for 1 hour, followed by cooling to room temperature, and the filtration velocity was recorded as 1300–1700 cm⁻¹. -1 The infrared spectrum covers a range. The correlation between temperature and acidity is well-known in the industry.

[0059] Data processing method: B(L) acidity = A × S / m. Where: A is absorbance; m is sample weight in g; S is sample cross-sectional area in cm². 2 Therefore, the unit of acidity B(L) calculated according to this formula is: Acm.2 g -1 .

[0060] NH3-TPD characterization was performed using an iChem 700 micrometer. The qualitative determination of strong Brønsted acid content was achieved using the NH3-TPD method. The specific procedure for the NH3-TPD method was as follows: Cu-SSZ-39 molecular sieve samples were compressed, crushed, and sieved. 20-40 mesh particles were dried for later use to obtain the sample to be tested. During the experiment, 0.15 g of the dried sample was accurately weighed and placed in a quartz tube. A quartz sand bed supported the zeolite bed and covered it with another quartz sand bed, positioning the zeolite bed at the thermocouple location. The sample was activated at 550 °C for 3 h under a He atmosphere, then cooled to room temperature to adsorb 100% ammonia for 20 min. The temperature was then raised to a constant 100 °C until the baseline stabilized. Finally, the temperature was increased to 650 °C at a rate of 10 °C / min, and the ammonia desorption signal was collected. The ammonia desorption temperature reflects the acid strength of the molecular sieve catalyst; a higher ammonia desorption temperature corresponds to a stronger acid strength.

[0061] Hydrogen-programmed reduction analysis of zeolite samples was performed using an iChem700 temperature-programmed chemisorption analyzer. 0.3 g of the sample was loaded into the reactor and purged at 400 °C for 1 h in a N2 atmosphere. After cooling to room temperature, a temperature-programmed reduction reaction was carried out in a gas flow of 15 ml / min with n(N2) / n(H2) = 9 / 1. The temperature was increased to 1100 °C at a rate of 10 °C / min, and multi-channel online sampling analysis was performed using a TCD detector.

[0062] SEM was used for sample morphology analysis. The scanning electron microscope was a HITACHI REgulus 8100 from Japan. The thoroughly dried samples were fixed onto a sample tray using conductive adhesive, and a vacuum was applied to 10 °C. -4 After Pa, physical gold plating is performed for 7-10 minutes, followed by scanning and testing.

[0063] X-ray fluorescence spectroscopy (XRF) was used to analyze the silica-alumina ratio in the bulk phase of the molecular sieve and the sodium content in the molecular sieve framework. The thoroughly dried molecular sieve was pressed into tablets at a pressure of 30 MPa using a tablet press, then cleaned with a blower before scanning and testing. Instrument model: Rigaku Smart Lab, Japan.

[0064] Example 1

[0065] Embodiment 1 of the present invention provides a catalyst, which is an AEI-configured zeolite molecular sieve catalyst containing copper ions introduced into the zeolite molecular sieve catalyst in the form of a copper source.

[0066] Embodiment 1 of the present invention provides a method for preparing the catalyst, comprising the following steps:

[0067] The first step is to prepare Cu-NaY molecular sieve: Weigh 38.2g of water glass into a beaker, adjust the water bath temperature to 50℃, stir and preheat for 5min, then add 32.5g of sodium aluminate solution and mix well. Weigh 1.3g of C4H6CuO4·H2O and dissolve it in 8.4g of sodium hydroxide solution, then add it to the mixture of water glass and sodium aluminate. Stir and age at this temperature for 5h to obtain crystallization guiding agent.

[0068] 300.5 g of water glass (SiO2 content 24.03 wt.%, Na2O content 7.26 wt.%) was added to a beaker and stirred in a 50 °C water bath. After 5 min, 6.5 g of 3 mol / L sulfuric acid was added dropwise and stirred for 30 min. The mixture was then allowed to stand at 50 °C for 5 h. Next, 87.2 g of sodium aluminate solution, 72.4 g of crystallization guide agent, 66.3 g of deionized water, and 4.6 g of C4H6CuO4·H2O were added and stirred for 4 h. Then, 186.0 g of aluminum sulfate was slowly added over 20 min until the solution thickened. The mixture was then aged for 6 h with rapid stirring and statically crystallized in a 100 °C oven for 72 h. After crystallization, the mixture was centrifuged, washed, and dried to obtain Cu-NaY-1 molecular sieve.

[0069] The second step is to prepare Cu-SSZ-39 molecular sieve: Cu-NaY-1 molecular sieve, silica sol, sodium hydroxide solution, organic template agent 2,2,6,6-tetramethylN,N-dimethylpiperidine, and deionized water are mixed according to the following ratios: CuO:Na2O:Al2O3:SiO2:H2O:organic template agent:0.37:35:1:48:800:35. The mixture undergoes a gelation reaction to obtain a second gel mixture. The obtained second gel mixture is then dynamically crystallized at 160℃ for 42 hours to obtain molecular sieve Cu-SSZ-39-1.

[0070] The third step is the preparation of Cu-SSZ-39 molecular sieve catalyst: 20g of Cu-SSZ-39 molecular sieve was calcined at 550℃ for 5h, followed by ammonium exchange. During the exchange process, 1mol / L HCl solution was added to adjust the pH to approximately 3.3. The sieve (dry basis): ammonium salt: water were slurried at a mass ratio of 1:1:10 and stirred at 90℃ for 1h to obtain ammonium-exchanged NH4-Cu-SSZ-39 molecular sieve. Then, the ammonium-exchanged NH4-Cu-SSZ-39 molecular sieve was subjected to hydrothermal treatment: the NH4-Cu-SSZ-39 molecular sieve was placed in a hydrothermal furnace at 650℃ and calcined in a 10% (volume) water vapor atmosphere for 50h. Finally, after pressing and sieving, a 40-60 mesh Cu-SSZ-39-1 molecular sieve catalyst was obtained.

[0071] The Cu-SSZ-39-1 molecular sieve catalyst in this embodiment has a relative crystallinity of 93%, a silicon-to-aluminum ratio of 14.7, and a specific surface area of ​​769 m². 2 / g, the pore volume of the molecular sieve is 0.29cm³. 3 / g, CuO content is 3.8wt%.

[0072] Comparative Example 1

[0073] Comparative Example 1 of the present invention provides a catalyst that does not contain copper ions introduced into the catalyst in the form of a copper source.

[0074] Comparative Example 1 of this invention provides a method for preparing the catalyst, comprising the following steps:

[0075] The first step is to prepare NaY molecular sieve: Weigh 38.2g of water glass into a beaker, adjust the water bath temperature to 50℃, stir and preheat for 5min, add 32.5g of sodium aluminate solution and mix well, then add 8.4g of sodium hydroxide solution to the mixture of water glass and sodium aluminate, and stir and age at this temperature for 5h.

[0076] 300.5g of water glass was added to a beaker and stirred in a 50℃ water bath. After 5 minutes, 87.2g of sodium aluminate solution, 72.4g of crystallization guide agent, and 66.3g of deionized water were added. Then, 186.0g of aluminum sulfate was slowly added over 20 minutes. The solution thickened and was then aged for 6 hours with rapid stirring. Finally, it was statically crystallized in a 100℃ oven for 72 hours. After crystallization, the solution was centrifuged, washed, and dried to obtain NaY-1* molecular sieve.

[0077] The second step is to prepare SSZ-39 molecular sieve: copper sulfate solution, NaY-1* molecular sieve, silica sol, sodium hydroxide solution, organic template agent 2-ethyl-N,N-dimethylpiperidine, and deionized water are mixed according to the following ratios: CuO:Na2O:Al2O3:SiO2:H2O:organic template agent: 0.28:35:1:48:800:35. A gelation reaction is carried out to obtain a second gel mixture. The obtained second gel mixture is dynamically crystallized at 160℃ for 50 hours to obtain molecular sieve SSZ-39-1*.

[0078] The third step is to prepare the SSZ-39 molecular sieve catalyst: Take 20g of SSZ-39-1* molecular sieve and slurry it according to the mass ratio of molecular sieve (dry basis): ammonium salt: water = 1:1:10. Stir and exchange it at 90℃ for 1h. Impregnate the ammonium-exchanged NH4-SSZ-39-1* molecular sieve with 2.5% CuO in equal volume. Then place it in a hydrothermal furnace at 650℃ and calcine it in a 10% (volume) water vapor atmosphere for 50h. Finally, after pressing and sieving, obtain the 40-60 mesh SSZ-39-1* molecular sieve catalyst.

[0079] The SSZ-39-1* molecular sieve catalyst in this comparative example has a relative crystallinity of 83%, a silica-alumina ratio of 13.3, and a specific surface area of ​​690 m². 2 / g, the pore volume of the molecular sieve is 0.27cm³. 3 / g.

[0080] Example 2

[0081] Embodiment 2 of the present invention provides a catalyst, which is an AEI-configured zeolite molecular sieve catalyst containing copper ions introduced into the zeolite molecular sieve catalyst in the form of a copper source.

[0082] Example 2 of this invention provides a method for preparing the catalyst, comprising the following steps:

[0083] The first step is to prepare Cu-NaY molecular sieves: Weigh 46.2g of water glass into a beaker, adjust the water bath temperature to 50℃, stir and preheat for 5min, then add 34.5g of sodium aluminate solution and mix well. Weigh 0.8g of CuSO4·5H2O and dissolve it in 7.4g of water. After CuSO4·5H2O dissolves, add the solution to the mixture of water glass and sodium aluminate, and stir and age at this temperature for 5h.

[0084] 320.0 g of water glass was added to a beaker and stirred in a 40°C water bath. After 5 min, 8.7 g of 3 mol / L sulfuric acid was added dropwise and stirred for 30 min. The mixture was then allowed to stand at 40°C for 5 h. Next, 89.8 g of sodium aluminate solution, 75.1 g of crystallization guide agent, 100.2 g of deionized water, and 13.8 g of CuSO4·5H2O were added and stirred for 3 h. Then, 191.3 g of aluminum sulfate was slowly added over 20 min until the solution thickened. The mixture was then aged for 3 h with rapid stirring and placed in a 103°C oven for static crystallization for 64 h. After crystallization, the mixture was centrifuged, washed, and dried to obtain Cu-NaY-2 molecular sieve.

[0085] The second step is to prepare Cu-SSZ-39 molecular sieve: Cu-NaY-2 molecular sieve, fumed silica, ammonia solution, organic template agent 2,2,6,6-tetramethyl-N-ethylpiperidine, and deionized water are mixed according to the following ratios: CuO:Na2O:Al2O3:SiO2:H2O:organic template agent: 0.28:40:1:55:830:38. The mixture undergoes a gelation reaction to obtain a second gel mixture. The obtained second gel mixture is then dynamically crystallized at 150℃ for 38 hours to obtain Cu-SSZ-39-2 molecular sieve.

[0086] The third step is to prepare the Cu-SSZ-39 molecular sieve catalyst: 20g of Cu-SSZ-39 molecular sieve was calcined at 550℃ for 5h, and then ammonium exchange was performed on it. During the exchange process, 1mol / L HNO3 solution was added to adjust the pH value to around 4. The sieve (dry basis): ammonium salt: water was slurried at a mass ratio of 1:1:10, and the mixture was stirred and exchanged at 90℃ for 1h to obtain the ammonium-exchanged NH4-Cu-SSZ-39 molecular sieve. Then, the ammonium-exchanged NH4-Cu-SSZ-39 molecular sieve was subjected to hydrothermal treatment: the NH4-Cu-SSZ-39 molecular sieve was placed in a hydrothermal furnace at 650℃ and calcined in a 10% (volume) water vapor atmosphere for 50h. Finally, after pressing and sieving, a 40-60 mesh Cu-SSZ-39-2 molecular sieve catalyst was obtained.

[0087] The Cu-SSZ-39-2 molecular sieve catalyst in this embodiment has a relative crystallinity of 98%, a silicon-to-aluminum ratio of 15.7, and a specific surface area of ​​789 m². 2 / g, the pore volume of the molecular sieve is 0.28cm³. 3 / g, CuO content is 3.3% wt.

[0088] Comparative Example 2

[0089] Comparative Example 2 of the present invention provides a catalyst in which the copper atoms are not introduced into the catalyst in the form of a copper source.

[0090] Comparative Example 2 of this invention provides a method for preparing the catalyst, comprising the following steps:

[0091] The first step is to prepare NaY molecular sieve: Weigh 48.2g of water glass into a beaker, adjust the water bath temperature to 50℃, stir and preheat for 5min, add 32.5g of sodium aluminate solution and mix evenly. Stir and age at this temperature for 5h.

[0092] 300.5g of water glass was added to a beaker and stirred in a 50℃ water bath. After 5 minutes, 87.2g of sodium aluminate solution, 72.4g of crystallization guide agent, 66.3g of deionized water, and 4.3g of Cu(OH)2 were added. Then, 186.0g of aluminum sulfate was slowly added over 20 minutes. The solution thickened and was then aged for 6 hours with rapid stirring. Finally, it was statically crystallized in a 100℃ oven for 72 hours. After crystallization, the solution was centrifuged, washed, and dried to obtain NaY-2* molecular sieve.

[0093] The second step is to prepare Cu-SSZ-39 molecular sieve: copper sulfate solution, NaY-2* molecular sieve, silica sol, sodium hydroxide solution, organic template agent 2-ethyl-N,N-dimethylpiperidine, and deionized water are mixed according to the following ratios: CuO:Na2O:Al2O3:SiO2:H2O:organic template agent: 0.11:21:1:35:600:8. A gelation reaction is carried out to obtain a second gel mixture. The obtained second gel mixture is dynamically crystallized at 160℃ for 50 hours to obtain the molecular sieve Cu-SSZ-39-2*.

[0094] The third step is to prepare Cu-SSZ-39 molecular sieve catalyst: Take 20g of SSZ-39-1* molecular sieve and slurry it according to the mass ratio of molecular sieve (dry basis): ammonium salt: water = 1:0.8:7. Stir and exchange the slurry at 70℃ for 1h. Place the ammonium-exchanged NH4-Cu-SSZ-39-2* molecular sieve in a hydrothermal furnace at 700℃ and calcine it in a 20% (volume) water vapor atmosphere for 40h. Finally, after pressing and sieving, obtain 40-60 mesh Cu-SSZ-39-2* molecular sieve catalyst.

[0095] The Cu-SSZ-39-2* molecular sieve catalyst in this embodiment has a relative crystallinity of 81%, a silicon-to-aluminum ratio of 14.7, and a specific surface area of ​​672 m². 2 / g, the pore volume of the molecular sieve is 0.25cm³. 3 / g.

[0096] Example 3

[0097] Embodiment 3 of the present invention provides a catalyst, which is an AEI-configured zeolite molecular sieve catalyst containing copper ions introduced into the zeolite molecular sieve catalyst in the form of a copper source.

[0098] Example 3 of this invention provides a method for preparing the catalyst, comprising the following steps:

[0099] The first step is to prepare Cu-NaY molecular sieves: Weigh 40.9g of water glass into a beaker, adjust the water bath temperature to 33℃, stir and preheat for 5min, then add 33.1g of sodium aluminate solution and mix well. Weigh 0.3g of CuSO4·5H2O and dissolve it in 8.4g of sodium hydroxide solution, then add it to the mixture of water glass and sodium aluminate. Stir and age at this temperature for 16h.

[0100] 340.5g of water glass was added to a beaker and stirred in a 45℃ water bath. After 5 minutes, 10.5g of 0.5mol / L nitric acid was added dropwise and stirred for 30 minutes. The mixture was then allowed to stand at 45℃ for 5 hours. Next, 92.7g of sodium aluminate solution, 77.6g of crystallization guide agent, 51.7g of deionized water, and 14.1g of CuSO4·5H2O were added and stirred for 5 hours. Then, 188.3g of aluminum sulfate was slowly added over 20 minutes until the solution thickened. The mixture was then aged for 3 hours with rapid stirring and statically crystallized in a 98℃ oven for 66 hours. After crystallization, the mixture was centrifuged, washed, and dried to obtain Cu-NaY-3 molecular sieve.

[0101] The second step is to prepare Cu-SSZ-39 molecular sieve: Cu-NaY-3 molecular sieve, silica sol, sodium hydroxide solution, organic template agent 2,2,6,6-tetramethyl-N-ethylpiperidine, and deionized water are mixed according to the following ratios: CuO:Na2O:Al2O3:SiO2:H2O:organic template agent: 0.29:28:1:37:810:40. The mixture undergoes a gelation reaction to obtain a second gel mixture. The obtained second gel mixture is then dynamically crystallized at 140℃ for 45 hours to obtain Cu-SSZ-39-3 molecular sieve.

[0102] The third step is the preparation of Cu-SSZ-39 molecular sieve catalyst: 20g of Cu-SSZ-39 molecular sieve was calcined at 550℃ for 5h, followed by ammonium exchange. During the exchange process, 1mol / L H2SO4 solution was added to adjust the pH to 4.5. The mixture was slurried according to a mass ratio of molecular sieve (dry basis): ammonium salt: water = 1:1:10, and stirred at 90℃ for 1h to obtain ammonium-exchanged NH4-Cu-SSZ-39 molecular sieve. Then, the ammonium-exchanged NH4-Cu-SSZ-39 molecular sieve was subjected to hydrothermal treatment: the NH4-Cu-SSZ-39 molecular sieve was placed in a hydrothermal furnace at 650℃ and calcined in a 10% (volume) water vapor atmosphere for 50h. Finally, after pressing and sieving, a 40-60 mesh Cu-SSZ-39-3 molecular sieve catalyst was obtained.

[0103] The Cu-SSZ-39-3 molecular sieve catalyst in this embodiment has a relative crystallinity of 99%, a silicon-to-aluminum ratio of 13.9, and a specific surface area of ​​794 m². 2 / g, the pore volume of the molecular sieve is 0.28cm³. 3 / g, CuO content is 3.1wt%.

[0104] Example 4

[0105] Embodiment 4 of the present invention provides a catalyst, which is an AEI-configured zeolite molecular sieve catalyst containing copper ions introduced into the zeolite molecular sieve catalyst in the form of a copper source.

[0106] Example 4 of this invention provides a method for preparing the catalyst, comprising the following steps:

[0107] The first step is to prepare Cu-NaY molecular sieves: Weigh 67.9g of water glass into a beaker, adjust the water bath temperature to 60℃, stir and preheat for 5min, then add 66.1g of sodium aluminate solution and mix well. Weigh 0.53g of CuSO4·5H2O and dissolve it in 11.2g of sodium hydroxide solution, then add it to the mixture of water glass and sodium aluminate. Stir and age at this temperature for 3h.

[0108] 348.5g of water glass was added to a beaker and stirred in a 45℃ water bath. After 5 minutes, 14.7g of 0.2mol / L oxalic acid was added dropwise and stirred for 30 minutes. The mixture was then allowed to stand at 55℃ for 2 hours. Next, 95.1g of sodium aluminate solution, 100.6g of crystallization guide agent, 120.7g of deionized water, and 11.4g of CuSO4·5H2O were added and stirred for 4 hours. Then, 192.4g of aluminum sulfate was slowly added over 20 minutes until the solution thickened. The mixture was then aged for 5 hours with rapid stirring and statically crystallized in a 110℃ oven for 75 hours. After crystallization, the mixture was centrifuged, washed, and dried to obtain Cu-NaY-4 molecular sieve.

[0109] The second step is to prepare Cu-SSZ-39 molecular sieve: Cu-NaY-4 molecular sieve, silica sol, sodium hydroxide solution, organic template agent 2,2,6,6-tetramethyl-N-ethylpiperidine, and deionized water are mixed according to the following ratios: CuO:Na2O:Al2O3:SiO2:H2O:organic template agent:0.41:49:1:47:880:42. The mixture undergoes a gelation reaction to obtain a second gel mixture. The obtained second gel mixture is then dynamically crystallized at 155℃ for 43 hours to obtain Cu-SSZ-39-4 molecular sieve.

[0110] The third step is the preparation of Cu-SSZ-39 molecular sieve catalyst: 20g of Cu-SSZ-39 molecular sieve is calcined at 550℃ for 5h, followed by ammonium exchange. During the exchange process, 1mol / L HCl solution is added to adjust the pH to around 5. The mixture is slurried according to a mass ratio of molecular sieve (dry basis): ammonium salt: water = 1:1:10, and stirred at 90℃ for 1h to obtain ammonium-exchanged NH4-Cu-SSZ-39 molecular sieve. Then, the ammonium-exchanged NH4-Cu-SSZ-39 molecular sieve is subjected to hydrothermal treatment: the NH4-Cu-SSZ-39 molecular sieve is placed in a hydrothermal furnace at 650℃ and calcined in a 10% (volume) water vapor atmosphere for 50h. Finally, after pressing and sieving, a 40-60 mesh Cu-SSZ-39-4 molecular sieve catalyst is obtained.

[0111] The Cu-SSZ-39-4 molecular sieve catalyst in this embodiment has a relative crystallinity of 101%, a silicon-to-aluminum ratio of 15.8, and a specific surface area of ​​771 m². 2 / g, the pore volume of the molecular sieve is 0.29cm³. 3 / g, CuO content is 4.9wt%.

[0112] Example 5

[0113] Embodiment 5 of the present invention provides a catalyst, which is an AEI-configured zeolite molecular sieve catalyst containing copper ions introduced into the zeolite molecular sieve catalyst in the form of a copper source.

[0114] Example 5 of this invention provides a method for preparing the catalyst, comprising the following steps:

[0115] The first step is to prepare Cu-NaY molecular sieves: Weigh 99.9g of water glass into a beaker, adjust the water bath temperature to 42℃, stir and preheat for 5min, then add 91.7g of sodium aluminate solution and mix well. Weigh 0.29g of CuSO4·5H2O and dissolve it in 6.1g of sodium hydroxide solution, then add it to the mixture of water glass and sodium aluminate. Stir and age at this temperature for 10h.

[0116] 378.2 g of water glass was added to a beaker and stirred in a 50°C water bath. After 5 min, 10.7 g of 1 mol / L hydrochloric acid was added dropwise and stirred for 30 min. The mixture was then allowed to stand at 50°C for 5 h. Next, 90.3 g of sodium aluminate solution, 103.8 g of crystallization guide agent, 72.9 g of deionized water, and 5.9 g of CuSO4·5H2O were added and stirred for 5 h. Then, 188.6 g of aluminum sulfate was slowly added over 20 min until the solution thickened. The mixture was then aged for 4 h with rapid stirring and statically crystallized in a 105°C oven for 60 h. After crystallization, the mixture was centrifuged, washed, and dried to obtain Cu-NaY-5 molecular sieve.

[0117] The second step is to prepare Cu-SSZ-39 molecular sieve: Cu-NaY-4 molecular sieve, silica sol, sodium hydroxide solution, organic template agent 2,2,6,6-tetramethyl-N-ethylpiperidine, and deionized water are mixed according to the following ratios: CuO:Na2O:Al2O3:SiO2:H2O:organic template agent:0.23:41:1:39:780:33. A gelation reaction is carried out to obtain a second gel mixture. The obtained second gel mixture is dynamically crystallized at 165℃ for 35 hours to obtain molecular sieve Cu-SSZ-39-5.

[0118] The third step is the preparation of Cu-SSZ-39 molecular sieve catalyst: 20g of Cu-SSZ-39 molecular sieve was calcined at 550℃ for 5h, followed by ammonium exchange. During the exchange process, 1mol / L HNO3 solution was added to adjust the pH value to within the range of 3.3. The mixture was slurried according to a mass ratio of molecular sieve (dry basis): ammonium salt: water = 1:1:10, and stirred at 90℃ for 1h to obtain ammonium-exchanged NH4-Cu-SSZ-39 molecular sieve. Then, the ammonium-exchanged NH4-Cu-SSZ-39 molecular sieve was subjected to hydrothermal treatment: the NH4-Cu-SSZ-39 molecular sieve was placed in a hydrothermal furnace at 650℃ and calcined in a 10% (volume) water vapor atmosphere for 50h. Finally, after pressing and sieving, a 40-60 mesh Cu-SSZ-39-5 molecular sieve catalyst was obtained.

[0119] The Cu-SSZ-39-5 molecular sieve catalyst in this embodiment has a relative crystallinity of 102%, a silicon-to-aluminum ratio of 14.8, and a specific surface area of ​​755 m². 2 / g, the pore volume of the molecular sieve is 0.28cm³. 3 / g, CuO content is 2.3wt%.

[0120] Example 6

[0121] Embodiment 6 of the present invention provides a catalyst, which is an AEI-configured zeolite molecular sieve catalyst containing copper ions introduced into the zeolite molecular sieve catalyst in the form of a copper source.

[0122] Example 6 of this invention provides a method for preparing the catalyst, comprising the following steps:

[0123] The first step is to prepare Cu-NaY molecular sieves: Weigh 81.4g of water glass into a beaker, adjust the water bath temperature to 51℃, stir and preheat for 5min, then add 83.1g of sodium aluminate solution and mix well. Weigh 0.35g of CuSO4·5H2O and dissolve it in 7.3g of sodium hydroxide solution, then add it to the mixture of water glass and sodium aluminate. Stir and age at this temperature for 6h.

[0124] 378.8 g of water glass was added to a beaker and stirred in a 55°C water bath. After 5 min, 10.9 g of 0.18 mol / L oxalic acid was added dropwise and stirred for 30 min. The mixture was then allowed to stand at 55°C for 5 h. Next, 92.7 g of sodium aluminate solution, 104.6 g of crystallization guide agent, 75.0 g of deionized water, and 6.8 g of CuSO4·5H2O were added and stirred for 6 h. Then, 189.9 g of aluminum sulfate was slowly added over 20 min until the solution thickened. The mixture was then aged for 5 h with rapid stirring and statically crystallized in a 100°C oven for 55 h. After crystallization, the mixture was centrifuged, washed, and dried to obtain Cu-NaY-6 molecular sieve.

[0125] The second step is to prepare Cu-SSZ-39 molecular sieve: Cu-NaY-6 molecular sieve, silica sol, sodium hydroxide solution, organic template agent 2,2,6,6-tetramethyl-N-ethylpiperidine, and deionized water are mixed according to the following ratios: CuO:Na2O:Al2O3:SiO2:H2O:organic template agent:0.32:37:1:42:790:38. The mixture undergoes a gelation reaction to obtain a second gel mixture. The obtained second gel mixture is then dynamically crystallized at 145℃ for 44 hours to obtain Cu-SSZ-39-6 molecular sieve.

[0126] The third step is the preparation of Cu-SSZ-39 molecular sieve catalyst: 20g of Cu-SSZ-39 molecular sieve was calcined at 550℃ for 5h, followed by ammonium exchange. During the exchange process, 1mol / L HCl solution was added to adjust the pH value to within the range of 2.5. The mixture was slurried according to a mass ratio of molecular sieve (dry basis): ammonium salt: water = 1:1:10, and stirred at 90℃ for 1h to obtain ammonium-exchanged NH4-Cu-SSZ-39 molecular sieve. Then, the ammonium-exchanged NH4-Cu-SSZ-39 molecular sieve was subjected to hydrothermal treatment: the NH4-Cu-SSZ-39 molecular sieve was placed in a hydrothermal furnace at 650℃ and calcined in a 10% (volume) water vapor atmosphere for 50h. Finally, after pressing and sieving, a 40-60 mesh Cu-SSZ-39-6 molecular sieve catalyst was obtained.

[0127] The Cu-SSZ-39-6 molecular sieve catalyst in this embodiment has a relative crystallinity of 99%, a silicon-to-aluminum ratio of 17.1, and a specific surface area of ​​769 m². 2 / g, the pore volume of the molecular sieve is 0.28cm³. 3 / g, CuO content is 3.5wt%.

[0128] The catalysts of this invention can be used in nitrogen oxide removal reactions, exhibiting high NOx conversion and high selectivity for N2 production in the selective catalytic reduction of ammonia. The catalysts obtained in the various embodiments and comparative examples were subjected to an NH3-SCR reaction, with NO2 being the reactant gas. X The volume fraction of NH3 is 300 ppm, the volume fraction of O2 is 10%, the volume fraction of water vapor is 10%-40%, N2 is used as the balance gas, and the space velocity is 80,000-300,000 h⁻¹. -1 .

[0129] The NOx conversion and N2 selectivity of the catalyst in the embodiments of the present invention are calculated according to equations (1) and (2), respectively:

[0130]

[0131]

[0132] In the above formula:

[0133] [NOx] in NOx inlet volume fraction, %; [NO x ] out The NOx outlet volume fraction is expressed as %.

[0134] [NO] in [NO] represents the inlet volume fraction, %; out NO is the outlet volume fraction, in %.

[0135] [N2O] out The N2O outlet volume fraction, %;

[0136] [NO2] out NO2 is the outlet volume fraction, %;

[0137] [NH3] in The inlet volume fraction of NH3, in %.

[0138] [NH3] out The NH3 outlet volume fraction, %.

[0139] The experimental results of NOx conversion and N2 selectivity of the catalysts in the embodiments of the present invention and the comparative catalysts are shown in Table 1 below:

[0140] Table 1

[0141]

[0142]

[0143] As can be seen from the table above, the catalysts prepared in Examples 1 to 6 of this invention, by introducing copper ions into the zeolite molecular sieve catalyst in the form of a copper source, exhibit significantly lower NO content compared to Comparative Example 1, which lacks copper ions. X The conversion rate is higher, and the N2 selectivity is stronger. Additionally, Comparative Example 2 also contains copper atoms, but they are not introduced into the catalyst as a copper source. Although the NO conversion rate of the catalyst in Comparative Example 2 is higher... X The conversion rate and N2 selectivity of the catalyst were higher than those of the comparative catalyst. X The conversion rate and N2 selectivity are good, but still not as good as the NO conversion rate of the catalysts prepared in Examples 1 to 6 of this invention. X Conversion rate and N2 selectivity.

[0144] The acidic sites of the molecular sieves in Examples 1 to 6 and Comparative Examples 1 to 2 were determined by pyridine-infrared spectroscopy. The acidity data of the catalysts in the examples and comparative examples are shown in Table 2 below:

[0145] Table 2

[0146]

[0147] Table 2 shows the test results of acidic sites on the surface of the molecular sieves prepared in Examples 1 to 6 and Comparative Examples 1 to 2 at temperatures of 200℃ and 350℃. It can be seen that the acid content on the surface of the molecular sieves prepared in the examples of this invention is significantly higher than that of the comparative molecular sieves. Furthermore, the distribution ratio of moderately strong acids (B acids) in the molecular sieves of the examples is higher than that of the comparative molecular sieves, and this high distribution is maintained even at high temperatures. This indicates that the activity of the molecular sieves prepared in the examples of this invention is significantly improved compared to that prepared in the comparative examples.

[0148] The above description is merely a specific embodiment of the present invention. Obviously, various modifications and combinations can be made without departing from the spirit and scope of the present invention. Accordingly, this specification and accompanying drawings are merely exemplary descriptions of the invention as defined by the appended claims, and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of the present invention. Clearly, those skilled in the art can make various alterations and modifications to the present invention without departing from its spirit and scope. Thus, if these modifications and variations of the present invention fall within the scope of the claims and their equivalents, the intent of the present invention includes these modifications and variations. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the scope of the claims.

Claims

1. A catalyst, characterized in that, The catalyst is an AEI-type zeolite molecular sieve catalyst, which contains copper ions introduced into the zeolite molecular sieve catalyst in the form of a copper source, and the amount of medium-strong acid in the zeolite molecular sieve catalyst accounts for 50%-70% of the total acid content; The zeolite molecular sieve catalyst is Cu-SSZ-39 molecular sieve, and the preparation process of Cu-SSZ-39 molecular sieve includes: using Cu-NaY molecular sieve, silicon source, alkaline solution, organic template agent and deionized water as raw materials to prepare Cu-SSZ-39 molecular sieve; The preparation process of the Cu-NaY molecular sieve includes: Step 101: Mix silicon source, aluminum source, copper source, alkaline solution and water and then age the mixture to produce a crystallization guiding agent; Step 102: Add the crystallization guide agent, alkali solution and water to the silicon source and stir evenly, then add the aluminum source and copper source in sequence, and then carry out the gelation reaction to obtain the first gel mixture; Step 103: Crystallize the first gel mixture to obtain Cu-NaY molecular sieve.

2. The catalyst according to claim 1, characterized in that, The specific surface area of ​​the zeolite molecular sieve catalyst is 755 m². 2 / g~794m 2 / g, the relative crystallinity of the zeolite molecular sieve catalyst is above 93%, and the silicon-to-aluminum ratio of the zeolite molecular sieve catalyst is (13~20):

1.

3. The catalyst according to claim 1, characterized in that, The zeolite molecular sieve catalyst contains 0.1% to 10% copper ions by mass.

4. A method for preparing a catalyst according to any one of claims 1 to 3, characterized in that, include: Step 200: Using Cu-NaY molecular sieve, silicon source, alkaline solution, organic template agent and deionized water as raw materials, Cu-SSZ-39 molecular sieve is prepared. The copper ions contained in the Cu-NaY molecular sieve are introduced into the Y-type molecular sieve framework in the form of copper source. Step 300: Prepare Cu-SSZ-39 molecular sieve catalyst.

5. The method for preparing the catalyst according to claim 4, characterized in that, Before preparing Cu-SSZ-39 molecular sieve using Cu-NaY molecular sieve, silicon source, alkaline solution, organic template agent, and deionized water as raw materials, the method further includes: Step 101: Mix silicon source, aluminum source, copper source, alkaline solution and water and then age the mixture to produce a crystallization guiding agent; Step 102: Add the crystallization guide agent, alkali solution and water to the silicon source and stir evenly, then add the aluminum source and copper source in sequence, and then carry out the gelation reaction to obtain the first gel mixture; Step 103: Crystallize the first gel mixture to obtain Cu-NaY molecular sieve.

6. The method for preparing the catalyst according to claim 5, characterized in that, In step 101, the aging temperature is 0℃~80℃, and the aging time is 1h~50h; In step 102, the stirring time is 1-20 hours, the mass content of the crystallization guiding agent in the first gel mixture is 1%-50%, and the gelation reaction time is 0.5 hours-15 hours. In step 103, the crystallization temperature is 0℃~80℃, and the crystallization time is 24h~140h.

7. The method for preparing the catalyst according to claim 4, characterized in that, In step 200, the preparation of Cu-SSZ-39 molecular sieve using Cu-NaY molecular sieve, silicon source, alkaline solution, organic template agent, and deionized water as raw materials includes: Step 201: Mix Cu-NaY molecular sieve, silicon source, alkaline solution, organic template agent and deionized water, and then carry out a gelation reaction to obtain a second gel mixture; Step 202: Crystallize the second gel mixture and then calcine it to obtain Cu-SSZ-39 molecular sieve.

8. The method for preparing the catalyst according to claim 7, characterized in that, In step 201, the second gel mixture is calculated as a mixture of copper oxide, sodium oxide, aluminum oxide, silica, water and organic template agent, wherein the molar ratio of copper oxide, sodium oxide, aluminum oxide, silica, water and organic template agent in the second gel mixture is (0.01~0.5):(5~50):1:(10~100):(500~1000):(5~20).

9. The method for preparing the catalyst according to claim 7, characterized in that, In step 202, the crystallization temperature is 100℃~180℃, and the crystallization time is 24h~80h; The calcination temperature is 300℃~700℃, the calcination time is 1h~10h, and the rate of heating to the calcination temperature is 1°C / min~30°C / min.

10. The method for preparing the catalyst according to claim 4, characterized in that, The organic template agent is at least one selected from N,N-dimethyl-N,N-bicyclononane, 2,2,6,6-tetramethyl-N,N-dimethylpiperidine, N-cyclooctyl-pyridine, 2,2,6,6-tetramethyl-N-ethylpiperidine, 2-ethyl-N,N-dimethylpiperidine, 3,5-dimethyl-N,N-dimethylpiperidine, tetrapropylammonium hydroxide, tetrapropylammonium bromide, tetraethylammonium hydroxide, tetraethylammonium bromide, triethylamine, or ethylenediamine.

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