All-aluminum-to-copper copper-based molecular sieve catalyst as well as preparation method and application thereof

Abstract

The invention provides an all-aluminum-to-copper copper-based molecular sieve catalyst as well as a preparation method and application thereof. The preparation method comprises the following steps: mixing an aluminum pair-containing molecular sieve and a copper source, and roasting to obtain the all-aluminum pair copper-based molecular sieve catalyst, wherein the roasting temperature is greater than or equal to 800 DEG C. According to the preparation method provided by the invention, copper in the copper-based molecular sieve catalyst exists in the form of an all-aluminum-to-copper active species in a high-temperature roasting environment of 800 DEG C or above, so that the copper-based molecular sieve catalyst has more excellent hydrothermal stability and sulfur resistance, shows excellent catalytic activity in the catalytic treatment process of nitrogen oxides in atmospheric pollutants, and is suitable for industrial production. And the copper source usage amount is greatly reduced, the operation method is simple, the cost is low, and the method is easy to implement and suitable for large-scale production.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalysts, and relates to an all-aluminum pair copper-based molecular sieve catalyst, a preparation method thereof, and uses thereof. Background Art

[0002] Nitrogen oxides (NO x ) are important air pollutants, mainly derived from stationary sources and mobile sources. The stationary sources are mainly coal-fired power plants, and the mobile sources are mainly diesel vehicle exhausts. NO x will cause environmental problems such as photochemical smog, acid rain, and ozone layer depletion. In addition, it has biological respiratory toxicity and is harmful to human health. Therefore, controlling nitrogen oxide emissions is extremely important. The selective catalytic reduction of NO by NH3 x , that is, the NH3-SCR technology (ammonia selective catalytic reduction), is currently widely used in the emission control of stationary sources and mobile sources of NO x emissions.

[0003] To meet the requirements of practical applications, the NH3-SCR catalyst must have excellent hydrothermal stability and sulfur resistance.

[0004] In recent years, small-pore molecular sieve catalysts have received extensive attention. For example, CN106745033A discloses a Cu-SSZ-50 zeolite catalyst, which has excellent NH3-SCR catalytic performance and lower cost, and has great application potential. However, in actual use, because the exhaust gas or flue gas generated by all combustion processes contains a certain amount of moisture, especially in the field of diesel vehicle exhaust purification, the front-end particulate trap will frequently undergo high-temperature active regeneration, thereby making the rear-end NH3-SCR catalyst in a periodic hydrothermal environment. Therefore, it is required that the NH3-SCR catalyst needs to have high hydrothermal stability to be applicable to the ability to remove NO x from the system for a long time. However, the hydrothermal stability of the current Cu-SSZ-50 small-pore molecular sieve catalyst cannot meet the requirements. After the Cu-SSZ-50 catalyst provided in CN106745033A undergoes a certain hydrothermal aging process, its NH3-SCR activity will be significantly reduced. 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 of the copper-based NH3-SCR molecular sieve catalyst generally have two active species: aluminum-paired copper and isolated aluminum copper. Aluminum-paired copper is more stable than isolated aluminum copper and has better sulfur resistance. The molecular sieve containing only aluminum-paired copper will have better hydrothermal stability and sulfur resistance. Therefore, controlling the copper species is very important. In the prior art, it is still difficult to control the copper species.

[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. Summary of the Invention

[0007] In response to the shortcomings of the prior art, the present invention aims to provide an all-aluminum-on-copper copper-based molecular sieve catalyst, its preparation method, and use. The preparation method provided by the present invention allows the copper in the copper-based molecular sieve catalyst to exist as an all-aluminum-on-copper active species under a high-temperature calcination environment above 800°C, resulting in superior hydrothermal stability and sulfur resistance. It exhibits excellent catalytic activity in the catalytic treatment of nitrogen oxides in atmospheric pollutants, while significantly reducing the amount of copper source used. The method is simple to operate, low-cost, and easily implementable, making it suitable for large-scale production.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a method for preparing an all-aluminum-copper copper-based molecular sieve catalyst, the preparation method comprising the following steps:

[0010] Mixing the aluminum-copper molecular sieve and a copper source, and calcining to obtain the all-aluminum-copper copper-based molecular sieve catalyst;

[0011] 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.

[0012] The preparation method provided by the present invention, under a high-temperature roasting environment of more than 800°C, all active copper species migrate to the more stable aluminum pair, so that the copper in the copper-based molecular sieve catalyst containing the aluminum pair exists as an active species of all aluminum pairs to copper, thereby having more excellent hydrothermal stability and sulfur resistance, and showing excellent catalytic activity in the catalytic treatment process 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.

[0013] In the present invention, 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 achieve the copper existing as an active species of all-aluminum-copper.

[0014] Preferably, the aluminum pair-containing molecular sieve comprises a small pore molecular sieve.

[0015] Preferably, the small pore molecular sieve comprises any one or a combination of at least two of CHA, LTA, AEI or AFX.

[0016] It should be noted that the preparation process of the aluminophosphate-containing molecular sieve is a conventional technical means, which can be prepared by those skilled in the art using conventional methods, or commercial products can be purchased and used directly.

[0017] Moreover, the molecular sieves provided by the present invention are not limited to the several types of molecular sieves provided above. Any conventional type of aluminophosphate-containing molecular sieve that can be known to those skilled in the art within a reasonable range is applicable to the present invention.

[0018] Preferably, the mixing method includes any one or a combination of at least two of the liquid-phase ion exchange method, the incipient wetness impregnation method, or the solid-phase grinding method, and preferably the incipient wetness impregnation method.

[0019] The mixing method provided by the present invention adopts the incipient wetness impregnation method, which can better achieve the precise control of the copper content (the copper loading amount in the product is the amount of the copper source actually added during the preparation process) and simplify the experimental operation; and the usage amount of the copper source is greatly reduced under the condition of the same copper loading amount, significantly reducing the cost.

[0020] Preferably, the liquid-phase ion exchange method includes:

[0021] Impregnating the aluminophosphate-containing molecular sieve in a copper source solution.

[0022] Preferably, the solid-phase grinding method includes:

[0023] Solid-phase grinding of the aluminophosphate-containing molecular sieve and the copper source.

[0024] Preferably, the incipient wetness impregnation method includes:

[0025] Dripping a copper source solution with a saturated water absorption amount into the aluminophosphate-containing molecular sieve and mixing and dispersing.

[0026] Preferably, the mixing and dispersing method includes stirring and / or grinding, and preferably grinding.

[0027] For the incipient wetness impregnation method provided by the present invention, the saturated water absorption amount is the saturated water absorption amount of the aluminophosphate-containing molecular sieve; and after dripping the copper source solution, the grinding method is adopted to achieve the precise control of the copper content and the simplification of the experiment.

[0028] Preferably, the grinding time is 5 min to 1 h, such as 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, etc.

[0029] Preferably, the mixed substance is dried and then calcined.

[0030] Preferably, the calcination temperature is 800 - 1000 °C, such as 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.

[0031] For the calcination temperature provided by the present invention, if the temperature is too low, isolated aluminum copper will be formed; while if the temperature is too high, it will instead affect the stability and catalytic activity of the molecular sieve.

[0032] Preferably, the calcination time is 1 - 10 h, such as 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h or 10 h, etc.

[0033] As a preferred technical solution, the preparation method includes the following steps:

[0034] Dropwise add a copper source solution with a saturated water absorption amount to the aluminum - containing zeolite, grind for 5 min - 1 h, dry, and calcine at 800 - 1000 °C to obtain the all - aluminum - paired copper - based zeolite catalyst.

[0035] In the second aspect, the present invention provides an all - aluminum - paired copper - based zeolite catalyst, and the all - aluminum - paired copper - based zeolite catalyst is prepared by the preparation method as described in the first aspect.

[0036] The catalyst provided by the present invention has a structural form in which copper is loaded onto the zeolite. Among them, the loaded copper exists as an all - aluminum - paired copper species in the zeolite; thus, high hydrothermal stability and sulfur resistance are achieved, and it has high catalytic activity and shows excellent catalytic activity in the catalytic treatment of nitrogen oxides in air pollutants.

[0037] Preferably, the copper loading amount in the all - aluminum - paired copper - based zeolite catalyst is 0.5 - 3 wt%, such as 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., and preferably 1 - 2.5 wt%.

[0038] The catalyst provided by the present invention also achieves a higher copper loading amount on the premise of using a low amount of copper source.

[0039] In the third aspect, the present invention further provides a use of the all - aluminum - paired copper - based zeolite catalyst as described in the second aspect, and the use includes using the all - aluminum - paired copper - based zeolite catalyst for ammonia selective catalytic reduction.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] The preparation method provided by the present invention enables copper in the molecular sieve catalyst containing aluminum pairs to exist as an active species of all-aluminum pair copper in a high-temperature roasting environment above 800 °C, thereby having more excellent hydrothermal stability and sulfur resistance, showing excellent catalytic activity in the catalytic treatment of nitrogen oxides in air pollutants, greatly reducing the usage amount of copper source, having a simple operation method, low cost, being easy to implement, and being suitable for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 Performance comparison chart of NO x conversion rates for the fresh catalysts (F) provided in Example 1 and Comparative Example 1 and after high-temperature water vapor treatment (A).

[0043] Figure 2 Performance comparison chart of NO x conversion rates for the fresh catalysts provided in Example 1 and Comparative Example 1, after sulfidation treatment (S) and sulfidation regeneration treatment (R).

[0044] Figure 3 XRD patterns for the fresh catalysts provided in Example 1 and Comparative Example 1 and after high-temperature water vapor treatment.

[0045] Figure 4 XRD patterns for the fresh catalysts provided in Example 1 and Comparative Example 1, after sulfidation treatment and sulfidation regeneration treatment.

[0046] Figure 5 H2-TPR spectra for the fresh catalysts provided in Example 1 and Comparative Example 1 and after high-temperature water vapor treatment.

[0047] Figure 6 NH3-DRIFT spectra of the catalysts provided in Example 1 and Comparative Example 1.

[0048] Figure 7 Performance comparison chart of NO x conversion rates for the fresh catalysts provided in Example 7 and Comparative Example 2 and after high-temperature water vapor treatment.

[0049] Figure 8 Performance comparison chart of NO x conversion rates for the fresh catalysts provided in Example 7 and Comparative Example 2, after sulfidation treatment and sulfidation regeneration treatment.

[0050] Figure 9 XRD patterns for the fresh catalysts provided in Example 7 and Comparative Example 2 and after high-temperature water vapor treatment.

[0051] Figure 10 XRD patterns of the fresh catalysts provided for Example 7 and Comparative Example 2, after sulfidation treatment and sulfidation regeneration treatment.

[0052] Figure 11 H2-TPR spectra of the fresh catalysts provided for Example 7 and Comparative Example 2 and after high-temperature steam treatment.

[0053] Figure 12 NH3-DRIFT spectra of the catalysts provided for Example 7 and Comparative Example 2. Detailed implementation manners

[0054] The technical solution of the present invention will be further described below through specific implementation manners. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0055] Exemplarily, the present invention provides a preparation method of H-CHA molecular sieve and a preparation method of H-LTA molecular sieve respectively:

[0056] H-CHA molecular sieve: The H-CHA molecular sieve used in the present invention is commercially available H-CHA synthesized by hydrothermal method.

[0057] H-LTA molecular sieve: H-LTA is synthesized by hydrothermal method using a silicon source, an aluminum source, tetramethylammonium hydroxide pentahydrate, an organic structure-directing agent and seeds.

[0058] The molecular sieves involved in the following examples and comparative examples are all prepared by the above preparation methods.

[0059] Example 1

[0060] This example provides a catalyst, wherein the catalyst is copper loaded on H-CHA molecular sieve, and copper exists as the species of all-aluminum to copper in the molecular sieve; the loading amount of copper is 1.3 wt%.

[0061] The preparation method includes the following steps:

[0062] Using copper nitrate as a precursor, copper is loaded on H-CHA by incipient wetness impregnation method. Specifically, weigh H-CHA and place it in an agate mortar, dropwise add copper nitrate solution with a saturated water absorption amount and grind thoroughly for 30 min, dry it and then calcine it in a muffle furnace at 800 °C for 8 h, and the catalyst is obtained after calcination.

[0063] Example 2

[0064] The difference between this example and Example 1 is that the calcination temperature in this example is 1000 °C.

[0065] The remaining preparation methods and parameters are the same as those in Example 1.

[0066] Example 3

[0067] The difference between this example and Example 1 is that the copper loading in this example is 2.7 wt%.

[0068] The remaining preparation methods and parameters are the same as those in Example 1.

[0069] Example 4

[0070] The difference between this example and Example 1 is that in this example, the H-CHA molecular sieve is placed in a beaker, and after adding copper nitrate with a saturated water absorption amount, stirring treatment is carried out (i.e., no grinding).

[0071] The remaining preparation methods and parameters are the same as those in Example 1.

[0072] Example 5

[0073] The difference between this example and Example 1 is that the calcination temperature in this example is 1200 °C.

[0074] The remaining preparation methods and parameters are the same as those in Example 1.

[0075] Example 6

[0076] Provide a catalyst, the catalyst is copper loaded on the H-CHA molecular sieve, and copper exists as an all-aluminum pair copper species in the molecular sieve; the copper loading is 1.3 wt%.

[0077] The preparation method includes the following steps:

[0078] Using copper nitrate as a precursor, copper is loaded on H-CHA by liquid-phase ion exchange method. Specifically, the H-CHA molecular sieve is impregnated in a 0.1 mol / L copper nitrate solution for ion exchange, dried and then calcined in a muffle furnace at 800 °C for 8 h to obtain the catalyst after calcination.

[0079] Example 7

[0080] This example provides a catalyst, the catalyst is copper loaded on the H-LTA molecular sieve, and copper exists as an all-aluminum pair copper species in the molecular sieve; the copper loading is 2.3 wt%.

[0081] The preparation method includes the following steps:

[0082] Using copper nitrate as a precursor, copper was loaded on H-LTA by the incipient wetness impregnation method. Specifically, H-CHA was weighed and placed in an agate mortar, and a copper nitrate solution with a saturated water absorption amount was added dropwise and thoroughly ground for 30 min. After drying, it was calcined in a muffle furnace at 800 °C for 8 h, and the catalyst was obtained after calcination.

[0083] Example 8

[0084] The difference between this example and Example 7 is that in this example, the L-LTA molecular sieve was placed in a beaker, and after adding a copper nitrate solution with a saturated water absorption amount, stirring treatment was carried out (i.e., no grinding).

[0085] The remaining preparation methods and parameters were the same as those in Example 1.

[0086] Comparative Example 1

[0087] The difference between this comparative example and Example 1 is that the calcination temperature in this comparative example was 550 °C.

[0088] The remaining preparation methods and parameters were the same as those in Example 1.

[0089] Comparative Example 2

[0090] The difference between this comparative example and Example 7 is that the calcination temperature in this comparative example was 550 °C.

[0091] The remaining preparation methods and parameters were the same as those in Example 1.

[0092] Perform performance tests on the catalysts in the H-CHA system (Examples 1-6 and Comparative Example 1):

[0093] Test process for NH3-SCR reaction activity:

[0094] Take the treated or untreated catalyst, perform tabletting, grinding, and sieving treatments, and take 40-60 mesh particles to carry out NH3-SCR reaction activity tests on a fixed-bed reactor, [NO]=[NH3]=500 ppm, [O 2] =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 , and the reaction temperature was 150-600 °C; NO, NH3, and by-products N2O and NO2 were all measured using an infrared gas analyzer (Antaris IGS);

[0095] (a) Base (F): The fresh catalysts provided in Examples {1-6} and Comparative Example 1 were directly subjected to NH3-SCR reaction activity tests;

[0096] (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 an environment of 10% H2O / air (i.e., a water vapor content of 10%), and then the NH3-SCR reaction activity test was carried out;

[0097] (c) Sulfidation treatment (S): In an environment of 100 ppm SO2, the catalysts provided in Examples 1-6 and Comparative Example 1 were sulfided at a treatment temperature of 400 °C for 5 h, and then the NH3-SCR reaction activity test was carried out;

[0098] (4) Sulfidation regeneration treatment (R): The catalysts provided in Examples 1-6 and Comparative Example 1 were first sulfided according to step (c), and then in an environment of 10% H2O / air (i.e., a water vapor content of 10%), high-temperature regeneration treatment was carried out at 600 °C for 2 h, and then the NH3-SCR reaction activity test was carried out.

[0099] Figure 1 Shows the performance comparison chart of NO x conversion rate of the fresh catalysts provided in Example 1 and Comparative Example 1 and after high-temperature steam treatment (A represents high-temperature steam treatment) (550 in the figure is the comparative example, and 800 is the example).

[0100] Figure 2 Shows the NO x conversion rate performance comparison chart of the fresh catalysts (F represents fresh catalyst), sulfidation treatment (S represents sulfidation treatment), and sulfidation regeneration treatment (R represents sulfidation regeneration treatment) provided in Example 1 and Comparative Example 1.

[0101] Figure 3 Shows the XRD patterns of the fresh catalysts provided in Example 1 and Comparative Example 1 and after high-temperature steam treatment.

[0102] Figure 4 Shows the XRD patterns of the fresh catalysts, sulfidation treatment, and sulfidation regeneration treatment provided in Example 1 and Comparative Example 1.

[0103] Figure 5 Shows the H2-TPR spectra of the fresh catalysts provided in Example 1 and Comparative Example 1 and after high-temperature steam treatment.

[0104] Figure 6 Shows the NH3-DRIFT spectra of the catalysts provided in Example 1 and Comparative Example 1.

[0105] It should be noted that Figures 1-6Among the text annotations, 800 represents Example 1, 550 represents Comparative Example 1, and the corresponding F represents a fresh catalyst, A represents high-temperature steam treatment before testing, S represents sulfidation treatment before testing, and R represents sulfidation regeneration treatment before surface testing.

[0106] From Figures 1-6 It can be seen that the catalyst provided by Example 1 has better hydrothermal stability and sulfur resistance than the catalyst provided by Comparative Example 1.

[0107] The test results under the above treatment or untreated conditions are all shown in Table 1.

[0108] Table 1

[0109]

[0110]

[0111] Perform performance tests on the catalysts under the H-LTA system (Examples 7-8 and Comparative Example 2):

[0112] Test process for NH3-SCR reaction activity:

[0113] Take the treated or untreated catalyst, perform tablet pressing, grinding, and sieving, and take 40-60 mesh particles to conduct NH3-SCR reaction activity tests on a fixed-bed reactor, [NO] = [NH3] = 500 ppm, [O 2] = 5%, [H2O] = 10%, N2 is used as the balance gas, the total gas flow rate is 500 mL / min, and the reaction space velocity is 100,000 h -1 , the reaction temperature is 150-600 °C; NO, NH3, and by-products N2O and NO2 are all measured using an infrared gas analyzer (Antaris IGS);

[0114] (a) Base (F): The fresh catalysts provided by Examples 7-8 and Comparative Example 2 are directly subjected to NH3-SCR reaction activity tests;

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

[0116] (c) Sulfidation treatment (S): In an environment of 100 ppm SO2, the catalysts provided by Examples 1-6 and Comparative Example 1 are sulfided at a treatment temperature of 400 °C for 5 h, and then NH3-SCR reaction activity tests are carried out;

[0117] (4) Sulfurization and regeneration treatment (R): The catalysts provided in Examples 7 - 8 and Comparative Example 2 were first subjected to sulfurization treatment according to step (c), and then high-temperature regeneration treatment at 600 °C for 2 h was carried out in an environment of 10% H2O / air (i.e., a water vapor content of 10%), and then the NH3-SCR reaction activity test was carried out.

[0118] Figure 7 The performance comparison diagram of the NO conversion rate of the fresh catalysts provided in Example 7 and Comparative Example 2 and after high-temperature water vapor treatment is shown. x

[0119] Figure 8 The performance comparison diagram of the NO conversion rate of the fresh catalysts provided in Example 7 and Comparative Example 2, after sulfurization treatment and sulfurization and regeneration treatment is shown. x

[0120] Figure 9 The XRD pattern of the fresh catalysts provided in Example 7 and Comparative Example 2 and after high-temperature water vapor treatment is shown.

[0121] Figure 10 The XRD pattern of the fresh catalysts provided in Example 7 and Comparative Example 2, after sulfurization treatment and sulfurization and regeneration treatment is shown.

[0122] Figure 11 The H2-TPR spectrum of the fresh catalysts provided in Example 7 and Comparative Example 2 and after high-temperature water vapor treatment is shown.

[0123] Figure 12 The NH3-DRIFT spectrum of the catalysts provided in Example 7 and Comparative Example 2 is shown.

[0124] It should be noted that Figures 7-12 in the text annotation, 800 is Example 7, 550 is Comparative Example 2, and the corresponding F represents that the catalyst was not treated before the test, A represents that high-temperature water vapor treatment was carried out before the test, S represents that sulfurization treatment was carried out before the test, and R represents that sulfurization and regeneration treatment was carried out before the test.

[0125] From Figures 7-12 it can be seen that 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 treatment or untreated conditions are all shown in Table 2.

[0127] Table 2

[0128]

[0129] ​

[0130] Combination Figures 1-12 Combined with Table 1 - Table 2, it can be obtained that:

[0131] The preparation method provided by the present invention is applicable to copper - loaded catalysts under a variety of molecular sieve systems containing aluminum pairs. The catalyst prepared by using the preparation method provided by the present invention significantly improves the hydrothermal stability and sulfur resistance in the NH3 - SCR reaction activity test.

[0132] From the comparison between Example 1 and Example 4, and between Example 7 and Example 8, it can be seen that when the incipient wetness impregnation method is used for preparation, grinding after dropping the solution can better achieve the precise control of copper content and the simplification of experimental operations, while conventional stirring cannot achieve the effect of sufficient and uniform mixing.

[0133] From the comparison between Example 1 and Example 5, it can be seen that if the calcination temperature is too high, exceeding 1000 °C, it will affect the stability and catalytic activity of the molecular sieve.

[0134] From the comparison between Example 1 and Example 6, it can be seen that when the liquid - phase ion - exchange method is used to mix the molecular sieve and the copper source, there are problems such as difficulty in precisely regulating the copper content, cumbersome operation process, large consumption of copper source, and high cost.

[0135] 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 calcination temperature is too low, lower than 800 °C, isolated aluminum - copper will be formed.

[0136] In summary, the preparation method provided by the present invention, under a high - temperature calcination environment above 800 °C, enables the copper in the copper - based molecular sieve catalyst containing aluminum pairs to exist as the active species of all - aluminum - pair copper, thereby having more excellent hydrothermal stability and sulfur resistance. It shows excellent catalytic activity in the catalytic treatment of nitrogen oxides in air pollutants, and the consumption of copper source is greatly reduced, the operation method is simple, the cost is low, it is easy to implement, and it is suitable for large - scale production.

[0137] The applicant declares that the above - mentioned is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by any person skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A method for preparing an all-aluminum-copper based molecular sieve catalyst, characterized in that: The preparation method comprises the following steps: Mixing the aluminum-copper molecular sieve and the 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, characterized in that: The aluminum pair-containing molecular sieve includes a small-pore molecular sieve; Preferably, the small pore molecular sieve comprises any one or a combination of at least two of CHA, LTA, AEI or AFX; 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.

3. The method for preparing the all-aluminum-copper based molecular sieve catalyst according to claim 2, characterized in that: The liquid phase ion exchange method comprises: The molecular sieve containing aluminum pairs is impregnated in a copper source solution.

4. The method for preparing the all-aluminum-copper-based molecular sieve catalyst according to claim 2 or 3, characterized in that: The solid phase grinding method comprises: Solid phase grinding of aluminum-containing molecular sieves and a copper source.

5. The method for preparing the all-aluminum-copper based molecular sieve catalyst according to any one of claims 2 to 4, characterized in that: 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.

6. The method for preparing the all-aluminum-copper based molecular sieve catalyst according to any one of claims 1 to 5, characterized in that: 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.

7. The method for preparing the all-aluminum-copper based molecular sieve catalyst according to any one of claims 1 to 6, characterized in that: 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.

8. An all-aluminum-copper copper-based molecular sieve catalyst, characterized in that: The all-aluminum-copper copper-based molecular sieve catalyst is prepared by the preparation method according to any one of claims 1 to 7.

9. The all-aluminum-copper-based molecular sieve catalyst according to claim 8, characterized in that: 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%.

10. Use of the all-aluminum-copper based molecular sieve catalyst as claimed in claim 8 or 9, characterized in that: The application includes using an all-aluminum-copper based molecular sieve catalyst for selective catalytic reduction of ammonia.

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