All-aluminum-pair-copper copper-based molecular sieve catalyst, preparation method therefor and use thereof

Abstract

The present application provides an all-aluminum-pair-copper copper-based molecular sieve catalyst, a preparation method therefor and a use thereof. The preparation method comprises the following steps: mixing an aluminum-pair-containing molecular sieve with a copper source, and performing calcination to obtain the all-aluminum-pair-copper copper-based molecular sieve catalyst, wherein the calcination temperature is greater than or equal to 800℃. According to the preparation method provided by the present application, in a high-temperature calcination environment at 800℃ or above, the copper in the copper-based molecular sieve catalyst is present as an active species of all-aluminum-pair-copper, so that the copper-based molecular sieve catalyst has superior hydrothermal stability and sulfur resistance, and exhibits excellent catalytic activity in the catalytic treatment process of nitrogen oxide in atmospheric pollutants; moreover, the usage amount of copper source is significantly reduced, the operation method is simple, the cost is low, and the preparation method is easy to implement and is suitable for large-scale production.

Description

An all-aluminum-copper copper-based molecular sieve catalyst and its preparation method and use Technical Field

[0001] The present application belongs to the field of catalyst technology and relates to an all-aluminum-copper-based molecular sieve catalyst and its preparation method and use. Background Art

[0002] Nitrogen oxides (NO x ) is an important air pollutant, mainly from fixed and mobile sources. The main fixed source is coal-fired power plants, and the main mobile source is diesel vehicle exhaust. x It can cause environmental problems such as photochemical smog, acid rain, and ozone layer depletion. In addition, NO x There is also biological respiratory toxicity, which is harmful to human health, so it is extremely important to control the emission of nitrogen oxides. x , namely ammonia selective catalytic reduction (NH3-SCR) technology, which is currently widely used in NO x Emission control.

[0003] In order to meet the requirements of practical applications, NH3-SCR catalysts must have excellent hydrothermal stability and sulfur resistance.

[0004] In recent years, small-pore molecular sieve catalysts have received widespread attention. For example, CN106745033A discloses a Cu-SSZ-50 zeolite catalyst, which has excellent NH3-SCR catalytic performance, lower cost, and great application potential. However, in actual use, because all exhaust gases or flue gases generated by combustion processes contain a certain amount of water, especially in the field of diesel exhaust purification, the particulate filter at the front end will frequently undergo high-temperature active regeneration, thereby placing the NH3-SCR catalyst at the back end in a periodic hydrothermal environment. Therefore, the NH3-SCR catalyst needs to have high hydrothermal stability to maintain the removal of NO from the system for a long time. x However, the hydrothermal stability of the Cu-SSZ-50 small-pore molecular sieve catalyst currently does not meet the requirements. The Cu-SSZ-50 catalyst provided by CN106745033A significantly decreases its NH3-SCR activity after undergoing a certain hydrothermal aging process. Therefore, further improving the hydrothermal stability of the Cu-SSZ-50 type catalyst with excellent catalytic performance is of great significance for further promoting the development and practical application of molecular sieve-type NH3-SCR.

[0005] The active copper species in copper-based NH3-SCR molecular sieve catalysts are generally aluminum-copper and isolated aluminum-copper. Aluminum-copper is more stable and has better sulfur resistance than isolated aluminum-copper. Molecular sieves containing only aluminum-copper exhibit better hydrothermal stability and sulfur resistance, making it crucial to control the copper species. However, this control is difficult to achieve with existing technologies.

[0006] Therefore, how to improve the hydrothermal stability and sulfur resistance of NH3-SCR molecular sieve catalysts is a technical problem that needs to be solved urgently.

[0007] Summary of the Invention

[0008] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0009] The present application provides an all-aluminum-on-copper copper-based molecular sieve catalyst, its preparation method, and use. In the preparation method provided herein, under a high-temperature calcination environment above 800°C, the copper in the copper-based molecular sieve catalyst exists as an all-aluminum-on-copper active species, exhibiting superior hydrothermal stability and sulfur resistance. It also exhibits excellent catalytic activity in the catalytic treatment of nitrogen oxides in atmospheric pollutants, while significantly reducing the amount of copper source used. The operation method is simple, low-cost, and easy to implement, making it suitable for large-scale production.

[0010] In a first aspect, the present application provides a method for preparing an all-aluminum-copper copper-based molecular sieve catalyst, the preparation method comprising the following steps:

[0011] Mixing the aluminum-copper molecular sieve and a copper source, and calcining to obtain the all-aluminum-copper copper-based molecular sieve catalyst;

[0012] Wherein, the calcination temperature is ≥800°C, for example, 800°C, 830°C, 850°C, 880°C, 900°C, 930°C, 950°C, 980°C, 1000°C, 1050°C, 1100°C, 1150°C or 1200°C, etc.

[0013] In the preparation method provided in the present application, under a high-temperature roasting environment of more than 800°C, all active copper species migrate to the more stable aluminum pairs, so that the copper in the copper-based molecular sieve catalyst containing aluminum pairs exists as an active species of all-aluminum pairs of copper, thereby having more excellent hydrothermal stability and sulfur resistance, and exhibiting excellent catalytic activity in the catalytic treatment of nitrogen oxides in atmospheric pollutants. The use of copper source is greatly reduced, the operation method is simple, low-cost, easy to implement, and suitable for large-scale production.

[0014] In the present application, if the calcination temperature is too low, below 800° C., part of the copper will exist in the form of isolated aluminum-copper, and it will be impossible to realize the existence of copper as an active species of all-aluminum-copper.

[0015] Preferably, the aluminum pair-containing molecular sieve comprises a small pore molecular sieve.

[0016] Preferably, the small pore molecular sieve comprises any one or a combination of at least two of CHA, LTA, AEI or AFX.

[0017] It should be noted that the preparation process of the aluminum-containing molecular sieve is a conventional technical means. Those skilled in the art can prepare it by themselves using conventional methods, or they can purchase commercial products and use them directly.

[0018] The molecular sieves provided in this application are not limited to the several types of molecular sieves provided above. Conventional molecular sieves containing aluminum pairs that can be known to those skilled in the art within a reasonable range are applicable to this application.

[0019] Preferably, the mixing method comprises any one of a liquid phase ion exchange method, an incipient wetness impregnation method or a solid phase grinding method, or a combination of at least two thereof, preferably the incipient wetness impregnation method.

[0020] In the mixing method provided in the present application, the incipient wetness impregnation method can better achieve precise control of the copper content (the copper loading in the product is the amount of copper source actually added during the preparation process) and simplification of experimental operations; and the amount of copper source used is greatly reduced under the same copper loading, which significantly reduces costs.

[0021] Preferably, the liquid phase ion exchange method comprises:

[0022] The molecular sieve containing aluminum pairs is impregnated in a copper source solution.

[0023] Preferably, the solid phase grinding method comprises:

[0024] Solid phase grinding of aluminum-containing molecular sieves and a copper source.

[0025] Preferably, the incipient wetness impregnation method comprises:

[0026] The copper source solution with saturated water absorption is added dropwise to the molecular sieve containing aluminum, and the mixture is mixed and dispersed.

[0027] Preferably, the mixing and dispersing method comprises stirring and / or grinding, preferably grinding.

[0028] In the incipient wetness impregnation method provided in the present application, the saturated water absorption capacity is the saturated water absorption capacity of the molecular sieve containing aluminum; and after the copper source solution is added dropwise, grinding is adopted to achieve precise control of the copper content and simplification of the experiment.

[0029] Preferably, the grinding time is 5 min to 1 h, for example, 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min or 1 h.

[0030] Preferably, the mixed material is dried and then calcined.

[0031] Preferably, the calcination temperature is 800-1000°C, for example, 800°C, 810°C, 820°C, 830°C, 840°C, 850°C, 860°C, 870°C, 880°C, 890°C, 900°C, 910°C, 920°C, 930°C, 940°C, 950°C, 960°C, 970°C, 980°C, 990°C or 1000°C, etc.

[0032] The calcination temperature provided in this application is too low, which will form isolated aluminum copper; while too high a temperature will affect the stability and catalytic activity of the molecular sieve.

[0033] Preferably, the calcination time is 1 to 10 h, for example, 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h or 10 h.

[0034] In a preferred embodiment of the present application, the preparation method comprises the following steps:

[0035] A copper source solution with a saturated water absorption capacity is added dropwise to the aluminum-containing molecular sieve, ground for 5 minutes to 1 hour, dried, and calcined at 800 to 1000° C. to obtain the all-aluminum-copper copper-based molecular sieve catalyst.

[0036] In a second aspect, the present application provides an all-aluminum-on-copper copper-based molecular sieve catalyst, which is prepared by the preparation method described in the first aspect.

[0037] The catalyst provided in the present application is a structural form in which copper is loaded onto a molecular sieve, wherein the loaded copper exists in the molecular sieve as an all-aluminum-to-copper species, thereby achieving high hydrothermal stability and sulfur resistance. It has high catalytic activity and exhibits excellent catalytic activity in the catalytic treatment of nitrogen oxides in atmospheric pollutants.

[0038] Preferably, the copper loading in the all-aluminum-to-copper copper-based molecular sieve catalyst is 0.5 to 3 wt%, for example, 0.5 wt%, 0.8 wt%, 1 wt%, 1.1 wt%, 1.2 wt%, 1.3 wt%, 1.4 wt%, 1.5 wt%, 1.6 wt%, 1.7 wt%, 1.8 wt%, 1.9 wt%, 2 wt%, 2.1 wt%, 2.2 wt%, 2.3 wt%, 2.4 wt%, 2.5 wt%, 2.8 wt% or 3 wt%, etc., preferably 1 to 2.5 wt%.

[0039] The catalyst provided in this application achieves a higher copper loading while using a low amount of copper source.

[0040] In a third aspect, the present application further provides a use of the all-aluminum-on-copper copper-based molecular sieve catalyst as described in the second aspect, wherein the use includes using the all-aluminum-on-copper copper-based molecular sieve catalyst for selective catalytic reduction of ammonia.

[0041] Compared with the prior art, this application has the following beneficial effects:

[0042] The preparation method provided in the present application enables the copper in the copper-based molecular sieve catalyst containing aluminum pairs to exist as active species of all-aluminum pairs of copper under a high-temperature roasting environment of above 800°C, thereby making the copper-based molecular sieve catalyst have more excellent hydrothermal stability and sulfur resistance, and exhibiting excellent catalytic activity in the catalytic treatment of nitrogen oxides in atmospheric pollutants, and the use of copper source is greatly reduced, the operation method is simple, low-cost, easy to implement, and suitable for large-scale production.

[0043] Still other aspects will become apparent upon reading and understanding the accompanying drawings and detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 shows the NO of fresh catalyst (F) and high temperature steam treatment (A) provided in Example 1 and Comparative Example 1. x Performance comparison chart of conversion rate.

[0045] Figure 2 shows the NO of fresh catalyst provided in Example 1 and Comparative Example 1, after sulfurization treatment (S) and sulfurization regeneration treatment (R). x Performance comparison chart of conversion rate.

[0046] FIG3 is an XRD diagram of the fresh catalyst provided in Example 1 and Comparative Example 1 and after high-temperature water vapor treatment.

[0047] FIG4 is an XRD diagram of the fresh catalyst provided in Example 1 and Comparative Example 1, after sulfidation treatment, and after sulfidation regeneration treatment.

[0048] FIG5 is an H2-TPR spectrum of the fresh catalyst provided in Example 1 and Comparative Example 1 and after high-temperature steam treatment.

[0049] FIG6 is an NH3-DRIFT spectrum of the catalysts provided in Example 1 and Comparative Example 1.

[0050] FIG7 shows the fresh catalyst provided in Example 7 and Comparative Example 2 and the NO after high temperature steam treatment. x Performance comparison chart of conversion rate.

[0051] FIG8 shows the NO of the fresh catalyst provided in Example 7 and Comparative Example 2, after sulfidation treatment and sulfidation regeneration treatment. x Performance comparison chart of conversion rate.

[0052] FIG9 is an XRD diagram of the fresh catalyst provided in Example 7 and Comparative Example 2 and after high-temperature water vapor treatment.

[0053] FIG10 is an XRD diagram of the fresh catalyst provided in Example 7 and Comparative Example 2, after sulfidation treatment, and after sulfidation regeneration treatment.

[0054] FIG11 is an H2-TPR spectrum of the fresh catalyst provided in Example 7 and Comparative Example 2 and after high-temperature steam treatment.

[0055] FIG12 is the NH3-DRIFT spectra of the catalysts provided in Example 7 and Comparative Example 2. DETAILED DESCRIPTION

[0056] The technical solution of the present application is further described below through specific implementation methods. Those skilled in the art should understand that the embodiments are only used to help understand the present application and should not be regarded as specific limitations of the present application.

[0057] This application provides a preparation method of H-CHA molecular sieve and a preparation method of H-LTA molecular sieve respectively:

[0058] H-CHA molecular sieve: The H-CHA molecular sieve used in this application is commercially synthesized H-CHA by hydrothermal method;

[0059] H-LTA molecular sieve: H-LTA is synthesized by a hydrothermal method using a silicon source, an aluminum source, tetramethylammonium hydroxide pentahydrate, an organic structure-directing agent, and a seed crystal.

[0060] The molecular sieves involved in the following examples and comparative examples were all prepared using the above-mentioned preparation method.

[0061] Example 1

[0062] This embodiment provides a catalyst, wherein the catalyst is copper loaded onto an H-CHA molecular sieve, and the copper exists in the molecular sieve as an all-aluminum-to-copper species; the copper loading is 1.3 wt %.

[0063] The preparation method comprises the following steps:

[0064] Copper nitrate was used as a precursor and copper was loaded on H-CHA by the incipient wetness impregnation method. Specifically, H-CHA was weighed and placed in an agate mortar, and a saturated water absorption amount of copper nitrate solution was added dropwise and fully ground for 30 minutes. After drying, the H-CHA was calcined in a muffle furnace at 850° C. for 8 hours to obtain the catalyst.

[0065] Example 2

[0066] The difference between this embodiment and embodiment 1 is that the calcination temperature in this embodiment is 1000°C.

[0067] The rest of the preparation methods and parameters were the same as those in Example 1.

[0068] Example 3

[0069] The difference between this embodiment and embodiment 1 is that the copper loading in this embodiment is 2.7 wt %.

[0070] The rest of the preparation methods and parameters were the same as those in Example 1.

[0071] Example 4

[0072] The difference between this embodiment and embodiment 1 is that in this embodiment, the H-CHA molecular sieve is placed in a beaker, copper nitrate with a saturated water absorption amount is added dropwise, and then stirring is performed (ie, grinding is not performed).

[0073] The rest of the preparation methods and parameters were the same as those in Example 1.

[0074] Example 5

[0075] The difference between this embodiment and embodiment 1 is that the calcination temperature in this embodiment is 1200°C.

[0076] The rest of the preparation methods and parameters were the same as those in Example 1.

[0077] Example 6

[0078] This embodiment provides a catalyst, wherein the catalyst is copper loaded onto an H-CHA molecular sieve, and the copper exists in the molecular sieve as an all-aluminum-to-copper species; the copper loading is 1.3 wt %.

[0079] The preparation method comprises the following steps:

[0080] Copper nitrate is used as a precursor, and copper is loaded on H-CHA by a liquid phase ion exchange method. Specifically, the H-CHA molecular sieve is immersed in a 0.1 mol / L copper nitrate solution for ion exchange, and then dried and calcined in a muffle furnace at 850° C. for 8 h to obtain the catalyst.

[0081] Example 7

[0082] This embodiment provides a catalyst, wherein the catalyst is copper loaded onto an H-LTA molecular sieve, and the copper exists in the molecular sieve as an all-aluminum-to-copper species; the copper loading amount is 2.3 wt %.

[0083] The preparation method comprises the following steps:

[0084] Using copper nitrate as a precursor, copper is loaded on H-LTA by the incipient wetness impregnation method. Specifically, H-LHA is weighed and placed in an agate mortar, and a saturated water absorption amount of copper nitrate solution is added dropwise and fully ground for 30 minutes. After drying, it is calcined in a muffle furnace at 850°C for 8 hours to obtain the catalyst.

[0085] Example 8

[0086] The difference between this embodiment and embodiment 7 is that in this embodiment, the H-LTA molecular sieve is placed in a beaker, and copper nitrate with a saturated water absorption amount is added dropwise, followed by stirring (ie, no grinding).

[0087] The rest of the preparation methods and parameters were the same as those in Example 1.

[0088] Comparative Example 1

[0089] The difference between this comparative example and Example 1 is that the calcination temperature in this comparative example is 550°C.

[0090] The rest of the preparation methods and parameters were the same as those in Example 1.

[0091] Comparative Example 2

[0092] The difference between this comparative example and Example 7 is that the calcination temperature in this comparative example is 550°C.

[0093] The rest of the preparation methods and parameters were the same as those in Example 1.

[0094] Performance tests were performed on the catalysts in the H-CHA system (Examples 1-6 and Comparative Example 1):

[0095] NH3-SCR reaction activity test process:

[0096] Treated or untreated catalysts were tableted, crushed, and sieved. Particles with a mesh size of 40 to 60 were used to test the NH3-SCR reaction activity in a fixed-bed reactor. [NO] = [NH3] = 500 ppm, [O2] = 5%, [H2O] = 10%, N2 was used as the balance gas, the total gas flow rate was 500 mL / min, and the reaction space velocity was 100,000 h -1 , the reaction temperature is 150~600℃; NO and NH3 as well as by-products N2O and NO2 are determined by infrared gas analyzer (Antaris IGS);

[0097] (a) Basic (F): The fresh catalysts provided in Examples 1-6 and Comparative Example 1 were directly tested for NH3-SCR reaction activity;

[0098] (b) High-Temperature Steam Treatment (A): The catalysts provided in Examples 1-6 and Comparative Example 1 were subjected to high-temperature steam treatment at 900°C for 12 h in a 10% H2O / air (i.e., 10% water vapor content) environment, and then subjected to NH3-SCR reaction activity testing.

[0099] (c) Sulfidation (S): The catalysts provided in Examples 1-6 and Comparative Example 1 were sulfided at 400° C. for 5 h in an environment of 100 ppm SO 2 , and then subjected to NH 3 -SCR reaction activity testing; and

[0100] (d) Sulfurization Regeneration (R): The catalysts provided in Examples 1-6 and Comparative Example 1 were first subjected to sulfidation treatment according to step (c), and then subjected to high-temperature regeneration treatment at 600°C for 2 hours in an environment of 10% H2O / air (i.e., 10% water vapor content). The NH3-SCR reaction activity was then tested.

[0101] FIG1 shows the NO of fresh catalyst provided in Example 1 and Comparative Example 1 and after high temperature steam treatment (A represents high temperature steam treatment). x Performance comparison chart of conversion rate (550 in the figure is a comparative example, 850 is an example).

[0102] FIG2 shows the NO of the fresh catalyst (F) provided in Example 1 and Comparative Example 1, after sulfidation treatment (S represents sulfidation treatment) and sulfidation regeneration treatment (R represents sulfidation regeneration treatment). x Performance comparison chart of conversion rate.

[0103] FIG3 shows the XRD patterns of the fresh catalysts provided in Example 1 and Comparative Example 1 and the catalysts after being treated with high-temperature water vapor.

[0104] FIG4 shows XRD patterns of the fresh catalyst provided in Example 1 and Comparative Example 1, the catalyst after sulfidation treatment, and the catalyst after sulfidation regeneration treatment.

[0105] FIG5 shows the H2-TPR spectra of the fresh catalyst provided in Example 1 and Comparative Example 1 and after high-temperature steam treatment.

[0106] FIG6 shows the NH3-DRIFT spectra of the catalysts provided in Example 1 and Comparative Example 1.

[0107] It should be noted that 850 in the text annotations in Figures 1-6 refers to Example 1, 550 refers to Comparative Example 1, and the corresponding F represents a fresh catalyst, A represents a high-temperature steam treatment before testing, S represents a sulfurization treatment before testing, and R represents a sulfurization regeneration treatment before testing.

[0108] As can be seen from Figures 1-6, the catalyst provided in Example 1 has better hydrothermal stability and sulfur resistance than the catalyst provided in Comparative Example 1.

[0109] The test results under the above-mentioned treatment or untreatment conditions are shown in Table 1.

[0110] Table 1

[0111] Performance tests were performed on the catalysts in the H-LTA system (Examples 7-8 and Comparative Example 2):

[0112] NH3-SCR reaction activity test process:

[0113] Treated or untreated catalysts were tableted, crushed, and sieved. Particles with a mesh size of 40 to 60 were used to test the NH3-SCR reaction activity in a fixed-bed reactor. [NO] = [NH3] = 500 ppm, [O2] = 5%, [H2O] = 10%, N2 was used as the balance gas, the total gas flow rate was 500 mL / min, and the reaction space velocity was 100,000 h -1 , the reaction temperature is 150~600℃; NO and NH3 as well as by-products N2O and NO2 are determined by infrared gas analyzer (Antaris IGS);

[0114] (a) Basic (F): The fresh catalysts provided in Examples 7-8 and Comparative Example 2 were directly tested for NH3-SCR reaction activity;

[0115] (b) High-Temperature Steam Treatment (A): The catalysts provided in Examples 7-8 and Comparative Example 2 were subjected to high-temperature steam treatment at 940°C for 12 h in a 10% H2O / air (i.e., 10% water vapor content) environment, and then subjected to NH3-SCR reaction activity testing.

[0116] (c) Sulfidation (S): The catalysts provided in Examples 1-6 and Comparative Example 1 were sulfided at 400° C. for 5 h in an environment of 100 ppm SO 2 , and then subjected to NH 3 -SCR reaction activity testing; and

[0117] (d) Sulfurization Regeneration (R): The catalysts provided in Examples 7-8 and Comparative Example 2 were first subjected to sulfidation treatment according to step (c), and then subjected to high-temperature regeneration treatment at 600°C for 2 hours in an environment of 10% H2O / air (i.e., 10% water vapor content). The NH3-SCR reaction activity was then tested.

[0118] FIG7 shows the fresh catalyst provided in Example 7 and Comparative Example 2 and the NO after high temperature steam treatment. x Performance comparison chart of conversion rate.

[0119] FIG8 shows the NO of the fresh catalyst provided in Example 7 and Comparative Example 2, the catalyst after sulfidation treatment and the catalyst after sulfidation regeneration treatment. x Performance comparison chart of conversion rate.

[0120] FIG9 shows the XRD patterns of the fresh catalysts provided in Example 7 and Comparative Example 2 and after being treated with high-temperature water vapor.

[0121] FIG10 shows XRD patterns of the fresh catalyst provided in Example 7 and Comparative Example 2, after sulfidation treatment, and after sulfidation regeneration treatment.

[0122] FIG11 shows the H2-TPR spectra of the fresh catalyst provided in Example 7 and Comparative Example 2 and after high-temperature steam treatment.

[0123] FIG12 shows the NH3-DRIFT spectra of the catalysts provided in Example 7 and Comparative Example 2.

[0124] It should be noted that 850 in the text annotations in Figures 7-12 refers to Example 7, 550 refers to Comparative Example 2, and the corresponding F represents that the catalyst was not treated before testing, A represents that it was treated with high-temperature water vapor before testing, S represents that it was vulcanized before testing, and R represents that it was vulcanized and regenerated before testing.

[0125] As can be seen from Figures 7-12, the catalyst provided in Example 7 has better hydrothermal stability and sulfur resistance than the catalyst provided in Comparative Example 2.

[0126] The test results under the above-mentioned treatment or untreatment conditions are shown in Table 2.

[0127] Table 2

[0128] Combining Figure 1-12 and Table 1-2, we can obtain:

[0129] The preparation method provided in this application is suitable for preparing copper-loaded catalysts in various aluminum-containing molecular sieve systems. The catalyst prepared by the preparation method provided in this application significantly improves the hydrothermal stability and sulfur resistance in the NH3-SCR reaction activity test.

[0130] From the comparison between Example 1 and Example 4, and Example 7 and Example 8, it can be seen that when the incipient wetness impregnation method is used for preparation, grinding after adding the solution dropwise can better achieve precise control of the copper content and simplify the experimental operation, while conventional stirring cannot achieve the effect of fully uniform mixing.

[0131] From the comparison between Example 1 and Example 5, it can be seen that if the calcination temperature is too high, exceeding 1000° C., the stability and catalytic activity of the molecular sieve will be affected.

[0132] From the comparison between Example 1 and Example 6, it can be seen that the mixing of molecular sieve and copper source by liquid phase ion exchange method has the problems of difficulty in accurately controlling the copper content, complicated operation process, large amount of copper source used and high cost.

[0133] From the data results of Example 1 and Comparative Example 1, and Example 7 and Comparative Example 2, it can be seen that if the roasting temperature is too low, below 800° C., isolated aluminum copper will be formed.

[0134] In summary, in the preparation method provided by the present application, under a high-temperature roasting environment of above 800°C, the copper in the copper-based molecular sieve catalyst containing aluminum pairs exists as an active species of all-aluminum-to-copper, thereby having more excellent hydrothermal stability and sulfur resistance, and exhibiting excellent catalytic activity in the catalytic treatment of nitrogen oxides in atmospheric pollutants, and the amount of copper source used is greatly reduced, the operation method is simple, low-cost, easy to implement, and suitable for large-scale production.

[0135] The applicant declares that the above is only a specific implementation method of the present application, but the protection scope of the present application is not limited thereto. Technical personnel in the relevant technical field should understand that any changes or substitutions that can be easily thought of by technical personnel in the relevant technical field within the technical scope disclosed in this application fall within the protection scope and disclosure scope of this application.

Claims

1. A method for preparing an all-aluminum-copper copper-based molecular sieve catalyst, comprising the following steps: Mixing the aluminum-copper molecular sieve and a copper source, and calcining to obtain the all-aluminum-copper copper-based molecular sieve catalyst; Wherein, the calcination temperature is ≥800°C.

2. The method for preparing the all-aluminum-copper based molecular sieve catalyst according to claim 1, wherein: The aluminum pair-containing molecular sieve includes a small pore molecular sieve.

3. The method for preparing the all-aluminum-copper based molecular sieve catalyst according to claim 2, wherein: The small pore molecular sieve includes any one of CHA, LTA, AEI or AFX, or a combination of at least two of them.

4. The method for preparing an all-aluminum-copper based molecular sieve catalyst according to any one of claims 1 to 3, wherein: The mixing method includes any one of liquid phase ion exchange method, incipient wetness impregnation method or solid phase grinding method, or a combination of at least two thereof, preferably incipient wetness impregnation method.

5. The method for preparing the all-aluminum-copper based molecular sieve catalyst according to claim 4, wherein: The liquid phase ion exchange method comprises: The molecular sieve containing aluminum pairs is impregnated in a copper source solution.

6. The method for preparing the all-aluminum-copper based molecular sieve catalyst according to claim 4 or 5, wherein: The solid phase grinding method comprises: Solid phase grinding of aluminum-containing molecular sieves and a copper source.

7. The method for preparing the all-aluminum-copper based molecular sieve catalyst according to any one of claims 4 to 6, wherein: The incipient wetness impregnation method comprises: Add the copper source solution with saturated water absorption capacity dropwise to the molecular sieve containing aluminum, and mix and disperse; Preferably, the mixing and dispersing method comprises stirring and / or grinding, preferably grinding; Preferably, the grinding time is 5 min to 1 h.

8. The method for preparing an all-aluminum-copper based molecular sieve catalyst according to any one of claims 1 to 7, wherein: The mixed material is dried and then roasted; Preferably, the calcination temperature is 800-1000°C; Preferably, the calcination time is 1 to 10 hours.

9. The method for preparing an all-aluminum-copper based molecular sieve catalyst according to any one of claims 1 to 8, wherein: The preparation method comprises the following steps: The copper source solution with saturated water absorption is added dropwise to the aluminum-containing molecular sieve, ground for 5 minutes to 1 hour, dried, and calcined at 800 to 1000° C. to obtain the all-aluminum-copper copper-based molecular sieve catalyst.

10. An all-aluminum-copper copper-based molecular sieve catalyst prepared by the preparation method according to any one of claims 1 to 9.

11. The all-aluminum-copper copper-based molecular sieve catalyst according to claim 10, wherein: The copper loading amount in the all-aluminum-to-copper copper-based molecular sieve catalyst is 0.5-3 wt%, preferably 1-2.5 wt%.

12. Use of the all-aluminum-on-copper copper-based molecular sieve catalyst as claimed in claim 10 or 11, comprising using the all-aluminum-on-copper copper-based molecular sieve catalyst for selective catalytic reduction of ammonia.

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