Cu-Fe-SSZ-13 molecular sieve, preparation method thereof, catalyst and application

Abstract

The invention provides a Cu-Fe-SSZ-13 molecular sieve, a preparation method of the Cu-Fe-SSZ-13 molecular sieve, a catalyst and application of the catalyst. The preparation method comprises the following steps: mixing a first iron source, a first silicon source, a first aluminum source and water to form a guiding agent precursor, and aging to obtain a crystallization guiding agent; mixing the crystallization guiding agent, a second silicon source, a second aluminum source, a second iron source and water to obtain a molecular sieve precursor, aging and crystallizing to obtain a Fe-NaY molecular sieve; and mixing the Fe-NaY molecular sieve, a third silicon source, Cu-polyamine, OSDA, water and the Cu-SSZ-13 molecular sieve seed crystal to obtain reaction gel, crystallizing and roasting to obtain the molecular sieve. The invention also provides the molecular sieve obtained by the preparation method, a catalyst prepared from the molecular sieve, and application of the catalyst in DeNOx reaction. The molecular sieve catalyst is high in acid content and large in specific surface area, and has relatively high low-temperature and high-temperature NOX reduction catalyst activity.

Description

Technical Field

[0001] The present invention relates to the technical field of catalyst materials, and in particular to a Cu-Fe-SSZ-13 molecular sieve, a preparation method thereof, a catalyst and applications thereof. Background Art

[0002] SSZ-13 molecular sieve has a chabazite (CHA) structure, which is composed of AlO4 and SiO4 tetrahedrons connected end to end through oxygen atoms, orderly arranged into an ellipsoidal cage with an eight-membered ring structure (0.73nm×1.2nm) and a three-dimensional cross-pore structure with a pore size of 0.38nm×0.38nm. Due to the orderly pore structure, good hydrothermal stability, a large number of surface proton acid centers and exchangeable cations, SSZ-13 has excellent performance in automobile exhaust NOx removal, methanol to olefins (MTO) and CO2 adsorption separation.

[0003] In NH3-SCR technology, WO3 or MoO3-loaded V2O5-TiO2 catalysts have been used as the main catalysts for denitrification of fixed and mobile sources. With increasingly stringent emission standards, in the exhaust after-treatment system of diesel vehicles that meet the National VI standard, the particulate filter (DPF) is placed before the selective catalytic reduction (SCR) after-treatment system. The regeneration of DPF will produce a high temperature and high humidity environment, which will greatly reduce the catalytic performance of SCR. Therefore, it is particularly important to develop a catalyst that has both high activity and high temperature hydrothermal stability.

[0004] In recent years, small pore molecular sieve catalysts have gradually gained favor in scientific research and industrial fields due to their excellent activity, selectivity and hydrothermal stability. Among them, Cu-Fe-SSZ-13 molecular sieve with CHA configuration is a typical representative of small pore molecular sieve catalysts.

[0005] At present, the introduction of copper atoms is mostly carried out by ion exchange, that is, the obtained CHA type molecular sieve and a certain concentration of copper salt solution are stirred at 80°C for several hours, then filtered and rinsed multiple times, and the obtained molecular sieve is dried and calcined at high temperature. In order to ensure that the introduced copper has a high dispersion and further increase the copper content in the molecular sieve, multiple ion exchange processes are often required. During the ion exchange process, the molecular sieve framework often undergoes hydrolysis, resulting in a significant decrease in the specific surface area and stability of the molecular sieve. Generally, the specific surface area of ​​the copper-containing molecular sieve obtained does not exceed 500m 2 / g; at the same time, the utilization rate of copper ions in the copper salt solution used for exchange is low, the washing process consumes a large amount of pure water and converts it into sewage, and the high-temperature roasting process is time-consuming and energy-consuming. The one-step synthesis of copper-containing CHA molecular sieves has obvious advantages.

[0006] In the traditional synthesis process of CHA-type zeolites, it is difficult to introduce copper and iron atoms into the zeolite by directly adding copper salts and iron salts. The one-step synthesis of copper- and iron-containing CHA-type zeolites is currently a challenge.

[0007] U.S. Patent No. 4544538 discloses a synthesis method of silicon-aluminum SSZ-13 zeolite molecular sieve for the first time. The organic template used is N, N, N-trimethyl-1-adamantanium, followed by organic templates such as choline chloride and benzyltrimethylammonium being successfully applied to the synthesis process of the zeolite molecular sieve. Xiao et al. synthesized Cu / SSZ-13 molecular sieve (CN102259892A) using a copperamine template one-step method. However, since the method introduces a large amount of Cu ions, the SSZ-13 molecular sieve carrier is not suitable for direct use as a catalyst. In addition, the Si / Al molar ratio achieved in the final product is relatively low (4-7). Therefore, the direct synthesis method based on Cu-TEPA complex as a unique organic structure directing agent (OSDA) for preparing SSZ-13 can not control Si / Al ratio and Cu content. Summary of the invention

[0008] In order to solve the above problems, the purpose of the present invention is to provide a Cu-Fe-SSZ-13 molecular sieve and its preparation method, catalyst and application. The present invention introduces Fe and Cu into SSZ-13 molecules to obtain a NO reduction catalyst with both high low temperature and high temperature. X The catalytic activity of Cu-Fe-SSZ-13 molecular sieve.

[0009] In order to achieve the above object, the present invention provides a method for preparing Cu-Fe-SSZ-13 molecular sieve, which comprises:

[0010] S1, mixing a first iron source, a first silicon source, a first aluminum source and water to form a directing agent precursor, and aging to obtain a crystallization directing agent (iron-containing crystallization directing agent);

[0011] S2, mixing the crystallization directing agent, the second silicon source, the second aluminum source, the second iron source and water to obtain a molecular sieve precursor, aging and crystallizing to obtain a Fe-NaY molecular sieve;

[0012] S3, mixing the Fe-NaY molecular sieve, the third silicon source, Cu-polyamine, OSDA (organic structure directing agent, also known as organic template), water, and Cu-SSZ-13 molecular sieve seed crystals, performing a gelation reaction to obtain a reaction gel, crystallizing, and calcining to obtain the Cu-Fe-SSZ-13 molecular sieve.

[0013] In the above preparation method, the chemical composition of the directing agent precursor satisfies the following molar ratio: Fe2O3:Al2O3=(0.01-0.5):1. Specifically, the molar ratio of Fe2O3 to Al2O3 can be 0.01:1, 0.05:1, 0.1:1, 0.15:1, 0.2:1, 0.25:1, 0.3:1, 0.35:1, 0.4:1, 0.45:1, 0.5:1 and other specific values, as well as a range with any two of the above specific values ​​as endpoints. Furthermore, the chemical composition of the directing agent precursor can also satisfy the following molar ratio: Fe2O3:Al2O3=0.05-0.3:1.

[0014] Furthermore, in the above preparation method, the chemical composition of the directing agent precursor satisfies the following molar ratio: Fe2O3:Na2O:Al2O3:SiO2:H2O=(0.01-0.5):(8-30):1:(8-30):(150-450). Specifically, in terms of molar parts, when Al2O3 is 1 part, Fe2O3 can be 0.01 parts, 0.05 parts, 0.1 parts, 0.15 parts, 0.2 parts, 0.25 parts, 0.3 parts, 0.35 parts, 0.4 parts, 0.45 parts, 0.5 parts and other specific values, as well as ranges with any two of the above specific values ​​as endpoints; Na2O can be 8 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts and other specific values, as well as ranges with any two of the above specific values ​​as endpoints; SiO2 can be 8 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts and other specific values, as well as ranges with any two of the above specific values ​​as endpoints; H2O can be 150 parts, 200 parts, 250 parts, 300 parts, 350 parts, 400 parts, 450 parts and other specific values, as well as ranges with any two of the above specific values ​​as endpoints.

[0015] Furthermore, the chemical composition of the directing agent precursor satisfies the following molar ratio: Fe2O3:Na2O:Al2O3:SiO2:H2O=(0.05-0.3):(8-30):1:(8-30):(150-450).

[0016] It is understood that the Na2O in the chemical composition of the present invention and the OH in the system - For the corresponding relationship, used to express alkalinity, the alkali applicable to the above chemical composition is not limited to sodium hydroxide.

[0017] In the above preparation method, in S1, the aging temperature is generally controlled to be 0-80°C, for example, it can be 0°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C and other specific values, as well as a range with any two of the above specific values ​​as endpoints; further, in S1, the aging temperature can be 15-65°C.

[0018] In the above preparation method, in S1, the aging time is generally controlled to be 1-50h, for example, it can be specific values ​​such as 1h, 2h, 5h, 10h, 20h, 30h, 40h, 50h, and a range with any two of the above specific values ​​as endpoints; further, in S1, the aging time can be 2-20h.

[0019] In the above preparation method, in S2, the chemical composition of the molecular sieve precursor can satisfy the following molar ratio: Fe2O3:Al2O3=(0.01-0.5): 1. Specifically, the molar ratio of Fe2O3 to Al2O3 can be 0.01:1, 0.05:1, 0.1:1, 0.15:1, 0.2:1, 0.25:1, 0.3:1, 0.35:1, 0.4:1, 0.45:1, 0.5:1 and other specific values, as well as a range with any two of the above specific values ​​as endpoints.

[0020] Furthermore, in the above preparation method, in S2, the chemical composition of the molecular sieve precursor can satisfy the following molar ratio: Fe2O3:Na2O:Al2O3:SiO2:H2O=(0.01-0.5):(1-6):1:(8-30):(100-350). Specifically, in terms of molar parts, when Al2O3 is 1 part, Fe2O3 can be 0.01 parts, 0.05 parts, 0.1 parts, 0.15 parts, 0.2 parts, 0.25 parts, 0.3 parts, 0.35 parts, 0.4 parts, 0.45 parts, 0.5 parts and other specific values, as well as ranges with any two of the above specific values ​​as endpoints; Na2O can be 1 parts, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts and other specific values, as well as ranges with any two of the above specific values ​​as endpoints; SiO2 can be 8 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts and other specific values, as well as ranges with any two of the above specific values ​​as endpoints; H2O can be 100 parts, 150 parts, 200 parts, 250 parts, 300 parts and other specific values, as well as ranges with any two of the above specific values ​​as endpoints.

[0021] In the above preparation method, in S2, the mass of the crystallization directing agent is generally 1%-50% of the mass of the first molecular sieve precursor, and can be specifically 1%, 3%, 5%, 7%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50% and other specific values, as well as a range with any two of the above specific values ​​as endpoints; further, the mass of the crystallization directing agent can be 3%-25% of the mass of the first molecular sieve precursor.

[0022] In the above preparation method, in S2, the pH value of the molecular sieve precursor can be controlled to be 11-13.5, for example, it can be 11, 11.5, 12, 12.5, 13, 13.5 and other specific values ​​and a range with any two of the above specific values ​​as endpoints. In some specific embodiments, the pH value of the molecular sieve precursor can be adjusted by controlling the amount of the crystallization directing agent, without the need to add acid to adjust the pH.

[0023] In the above preparation method, in S2, the aging temperature can be 10-80°C, for example, it can be specific values ​​such as 10°C, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, and a range with any two of the above specific values ​​as endpoints; the aging time can be 0.5-15h, for example, it can be specific values ​​such as 0.5h, 1h, 5h, 10h, 15h, and a range with any two of the above specific values ​​as endpoints.

[0024] In some specific embodiments, the aging in S2 may include a first aging and a second aging. The specific process of S2 may include: adjusting the pH value of the second silicon source (adjustable silicon source hydrolysis) and then performing a first aging, then adding a second aluminum source, a crystallization directing agent, water, and a second iron source to form a molecular sieve precursor, and then performing a second aging, crystallization, to obtain a Fe-NaY molecular sieve. The temperatures of the first aging and the second aging can be controlled to be 10-80°C, respectively, and the sum of the time of the first aging and the second aging can be controlled to be 0.5-15h. By performing two agings, Fe can be more easily combined with the molecular sieve.

[0025] In the above preparation method, in S2, the crystallization temperature can be 80-140°C, for example, specific values ​​such as 80°C, 85°C, 90°C, 95°C, 100°C, 110°C, 120°C, 130°C, 140°C, and a range with any two of the above specific values ​​as endpoints; further, the crystallization temperature can be 85-120°C.

[0026] In the above preparation method, in S2, the crystallization time may be 24-140 hours, for example, specific values ​​such as 24 hours, 30 hours, 40 hours, 50 hours, 60 hours, 70 hours, 80 hours, 90 hours, 100 hours, 110 hours, 120 hours, 130 hours, 140 hours, and ranges with any two of the above specific values ​​as endpoints. Further, the crystallization time may be 30-100 hours.

[0027] In some specific embodiments, the crystallization of S2 can be static crystallization or dynamic crystallization, and static crystallization is preferred.

[0028] In the above preparation method, S2 also includes post-processing operations such as centrifugation, washing, and drying of the crystallized product. The operation process and parameters of the above post-processing can adopt processes well known to ordinary technicians in the field, and the present invention has no special restrictions on them.

[0029] In the above preparation method, in S3, the chemical composition of the reaction gel satisfies the following molar ratio: Al2O3:Cu-polyamine=1:(1-20). Specifically, the molar ratio of Cu-polyamine to Al2O3 can be 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 15:1, 20:1 and other specific values, as well as a range with any two of the above specific values ​​as endpoints.

[0030] In the above preparation method, in S3, the chemical composition of the reaction gel satisfies the following molar ratio: Fe2O3:Al2O3=0.005-0.3. Specifically, the molar ratio of Fe2O3 to Al2O3 can be 0.005:1, 0.01:1, 0.05:1, 0.1:1, 0.15:1, 0.2:1, 0.25:1, 0.3:1 and other specific values, as well as a range with any two of the above specific values ​​as endpoints; for example, it can be 0.005-0.2:1.

[0031] Furthermore, in the above preparation method, in S3, the chemical composition of the reaction gel satisfies the following molar ratio: Fe2O3:Na2O:Al2O3:SiO2:H2O:OSDA:Cu-polyamine = (0.005-0.3):(5-50):1:(10-100):(300-1000):(5-20):(1-20). Specifically, in terms of molar parts, when Al2O3 is 1 part, Fe2O3 can be 0.005 parts, 0.01 parts, 0.05 parts, 0.1 parts, 0.15 parts, 0.2 parts, 0.25 parts, 0.3 parts and other specific values, as well as ranges with any two of the above specific values ​​as endpoints; Na2O can be 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts; SiO2 can be 10 parts, 20 parts, 30 parts, 40 parts, 50 parts, 60 parts, 70 parts, 80 parts, 90 parts, 100 parts and other specific values, as well as ranges with any two of the above specific values ​​as endpoints. any two of the above specific values ​​as endpoints; H2O can be 300 parts, 500 parts, 700 parts, 900 parts, 1000 parts and other specific values, as well as a range with any two of the above specific values ​​as endpoints; OSDA can be 5 parts, 7 parts, 9 parts, 10 parts, 11 parts, 13 parts, 15 parts, 17 parts, 19 parts, 20 parts and other specific values, as well as a range with any two of the above specific values ​​as endpoints; Cu-polyamine can be 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 15 parts, 20 parts and other specific values, as well as a range with any two of the above specific values ​​as endpoints.

[0032] In some specific embodiments, in S3, the chemical composition of the reaction gel can satisfy the following molar ratio: Fe2O3:Na2O:Al2O3:SiO2:H2O:OSDA:Cu-polyamine = (0.005-0.2):(5-50):1:(10-100):(300-1000):(5-20):(1-20).

[0033] In the above preparation method, in S3, Fe-NaY molecular sieve, the third silicon source, Cu-polyamine, OSDA, water, and Cu-SSZ-13 molecular sieve seed crystals are mixed and stirred to form a reaction gel; in some specific embodiments, a gelation reaction may occur during the stirring process to promote the formation of a gel. The stirring may be carried out at room temperature and pressure, for example, the stirring temperature may be 40-60°C, and the stirring time may be 1.5-3h. Accordingly, the temperature of the gelation reaction may be 40-60°C, and the time of the gelation reaction may be 1.5-3h.

[0034] In the above preparation method, in S3, the mass of the Cu-SSZ-13 molecular sieve seed crystals is 1%-10% of the total mass of the reaction gel. The seed crystals can be added before or during crystallization.

[0035] In the above preparation method, in S3, the crystallization temperature is 100-200°C, for example, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C and other specific values, and a range with any two of the above specific values ​​as endpoints; the crystallization time is 24-80h, for example, 24h, 30h, 40h, 50h, 60h, 70h, 80h and other specific values, and a range with any two of the above specific values ​​as endpoints. In some specific embodiments, the crystallization of S3 can be dynamic crystallization or static crystallization, preferably dynamic crystallization.

[0036] In the above preparation method, in S3, the calcination temperature is 300-700°C, and the calcination time can be 1-10h. The calcination process can specifically include: heating to 300-700°C, keeping the temperature for 1-10h for calcination, and the heating rate of the heating is 1-30°C / min. By controlling the calcination speed, the destruction of the molecular sieve structure and the decrease in crystallinity caused by too fast a calcination speed can be avoided. In some specific embodiments, the calcination temperature can be 300°C, 400°C, 500°C, 600°C, 700°C and other specific values, as well as a range with any two of the above specific values ​​as endpoints; the calcination time can be 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h and other specific values, as well as a range with any two of the above specific values ​​as endpoints; the heating rate can be 1°C / min, 2°C / min, 3°C / min, 4°C / min, 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min, 10°C / min, 15°C / min, 20°C / min, 25°C / min, 30°C / min and other specific values, as well as a range with any two of the above specific values ​​as endpoints, for example, the heating rate can be 3-8°C / min.

[0037] In the above preparation method, S3 also includes a process of post-treating the crystallized product, including cooling, filtering, washing and drying the crystallized product after the crystallization is completed. The crystallized product after the above post-treatment is used for subsequent calcination.

[0038] In the above preparation method, the first silicon source includes water glass and / or silica sol.

[0039] In the above preparation method, the first aluminum source includes one or a combination of two or more of pseudo-boehmite, sodium aluminate, aluminum sulfate, aluminum nitrate and aluminum chloride.

[0040] In the above preparation method, the directing agent precursor of S1 may further include a first alkali solution. The first alkali solution includes one or a combination of two or more of sodium hydroxide solution, ammonia water, and sodium bicarbonate solution. The first alkali solution is used to adjust the alkalinity of the directing agent precursor and is an optional added component. For example, when the chemical composition of the directing agent precursor satisfies Na2O:Al2O3:SiO2=(8-30):1:(8-30), there is no need to add the first alkali solution.

[0041] In the above preparation method, the first iron source includes one or a combination of two or more of ferric nitrate, ferric chloride, ferrous chloride, and ferric hydroxide.

[0042] In the above preparation method, the second silicon source includes water glass and / or silica sol.

[0043] In the above preparation method, the second aluminum source includes one or a combination of two or more of pseudo-boehmite, sodium aluminate, aluminum sulfate, aluminum nitrate and aluminum chloride.

[0044] In the above preparation method, the molecular sieve precursor of S2 may further include a second alkali solution. The second alkali solution includes one or a combination of two or more of sodium hydroxide solution, ammonia water, and sodium bicarbonate solution. The second alkali solution is used to adjust the alkalinity of the molecular sieve precursor and is an optional added component. For example, when the chemical composition of the molecular sieve precursor satisfies Na2O:Al2O3:SiO2=(1-6):1:(8-30), there is no need to add the second alkali solution.

[0045] In the above preparation method, the second iron source includes one or a combination of two or more of ferric nitrate, ferric chloride, ferrous chloride, and ferric hydroxide.

[0046] In the above preparation method, the raw materials of the reaction gel of S3 may further include a third alkali solution. The third alkali solution includes one or a combination of two or more of sodium aluminate, sodium hydroxide solution, ammonia water, and sodium bicarbonate solution. The third alkali solution is used to adjust the alkalinity of the directing agent precursor and is an optional added component. For example, when the chemical composition of the reaction gel satisfies Na2O:Al2O3:SiO2=(5-50):1:(10-100), there is no need to add the third alkali solution.

[0047] In the above preparation method, the third silicon source includes one or a combination of two or more of water glass, silica sol, white carbon black, tetramethyl orthosilicate, tetraethyl orthosilicate, tetrapropyl orthosilicate, and tetrabutyl orthosilicate.

[0048] In the above preparation method, the OSDA includes one of N,N,N-trimethyl-1-adamantanammonium or benzyltrimethylammonium cationic compounds.

[0049] In the above preparation method, Cu-polyamine is a complex of Cu and polyamine, and the molar ratio of Cu to polyamine in the Cu-polyamine can be (0.9-1.1):1, specifically 0.9:1, 0.95:1, 1:1, 1.05:1, 1.1:1 and other specific values, as well as a range with any two of the above specific values ​​as endpoints, and can preferably be 1:1.

[0050] In the above Cu-polyamine, the polyamine includes one or a combination of two or more of primary amine, secondary amine and tertiary amine. Specifically, the polyamine may include one or a combination of two or more of tetraethylenepentamine, triethylenetetramine, 1,4,8,11-tetraazacyclotetradecane and 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane.

[0051] The present invention has found that if copper is introduced into the molecular sieve using copper inorganic salt as the copper source, the copper easily enters the molecular sieve but also easily leaks out of the molecular sieve; the present invention uses Cu-polyamine as the copper source, although the copper in the Cu-polyamine is more difficult to enter the molecular sieve than the copper in the copper salt and it is difficult for all of the copper to enter the molecular sieve, once the copper from the Cu-polyamine enters the molecular sieve, it can be firmly combined with the molecular sieve and is not easy to leak out, thus having high stability.

[0052] According to an embodiment of the present invention, the preparation method of the above-mentioned Cu-Fe-SSZ-13 molecular sieve may specifically include:

[0053] S1, mixing a first iron source, a first silicon source, a first aluminum source and water (optionally also comprising a first alkali solution) to form a directing agent precursor, wherein the chemical composition of the directing agent precursor satisfies the following molar ratio: Fe2O3:Na2O:Al2O3:SiO2:H2O=(0.01-0.5):(8-30):1:(8-30):(150-450);

[0054] Aging the directing agent precursor at 0-80° C. for 1-50 hours to obtain a crystallized directing agent;

[0055] S2, mixing a crystallization directing agent, water and a second silicon source (optionally also comprising a second alkali solution), stirring for 1-20 hours, adding a second aluminum source, and then adding a second iron source to obtain a molecular sieve precursor, and aging at a temperature of 10-80°C for 0.5-15 hours; wherein the chemical composition of the molecular sieve precursor satisfies the following molar ratio: Fe2O3:Na2O:Al2O3:SiO2:H2O=(0.01-0.5):(1-6):1:(8-30):(100-350); the mass of the crystallization directing agent is 1%-50% of the mass of the molecular sieve precursor;

[0056] The aged molecular sieve precursor is statically crystallized at 80-140° C. for 24-140 hours, and then the crystallized product is centrifuged, washed, and dried to obtain a Fe-NaY molecular sieve;

[0057] S3, mixing Fe-NaY molecular sieve, a third silicon source, Cu-polyamine, OSDA, water, and Cu-SSZ-13 molecular sieve seed crystals (optionally also comprising a third alkali solution) to obtain a reaction gel, wherein the chemical composition of the reaction gel satisfies the following molar ratio: Fe2O3: Na2O: Al2O3: SiO2: H2O: OSDA: Cu-polyamine = (0.005-0.3): (5-50): 1: (10-100): (300-1000): (5-20): (1-20);

[0058] The mass of Cu-SSZ-13 molecular sieve seed crystals is 1%-10% of the mass of the reaction gel; the seed crystals can be added before crystallization or during the crystallization process;

[0059] The reaction gel is dynamically crystallized at 100-200°C for 24-80h, the crystallized product is cooled, filtered, washed, dried, and then heated to 300-700°C at a heating rate of 1-30°C / min and calcined for 1-10h to obtain a Cu-Fe-SSZ-13 molecular sieve.

[0060] The present invention also provides a Cu-Fe-SSZ-13 molecular sieve, which is obtained by the above preparation method.

[0061] According to a specific embodiment of the present invention, taking the total mass of the molecular sieve as 100%, the mass of the element is calculated as the mass of the oxide, the mass content of the Cu element in the Cu-Fe-SSZ-13 molecular sieve is 0.1%-10%; the mass content of the Fe element in the Cu-Fe-SSZ-13 molecular sieve is 0.1%-3%; the strong acid content of the Cu-Fe-SSZ-13 molecular sieve is 40%-70% of the total acid content. In some specific embodiments, the strong acid in the above-mentioned Cu-Fe-SSZ-13 molecular sieve is mainly B acid (protonic acid).

[0062] According to a specific embodiment of the present invention, the mass content of the Cu element in the Cu-Fe-SSZ-13 molecular sieve is generally 0.1%-10%, and can further be 1.0%-8.0%.

[0063] According to a specific embodiment of the present invention, the mass content of the Fe element in the Cu-Fe-SSZ-13 molecular sieve is generally 0.1%-3%, and can further be 0.3%-1.5%.

[0064] According to a specific embodiment of the present invention, the specific surface area of ​​the Cu-Fe-SSZ-13 molecular sieve is ≥680m 2 / g; further, the specific surface area of ​​the Cu-Fe-SSZ-13 molecular sieve is ≥700m 2 / g; Furthermore, the specific surface area of ​​the Cu-Fe-SSZ-13 molecular sieve is ≥780m 2 / g.

[0065] According to a specific embodiment of the present invention, the SiO2 / Al2O3 molar ratio of the Cu-Fe-SSZ-13 molecular sieve is ≥10; further, the SiO2 / Al2O3 molar ratio of the Cu-Fe-SSZ-13 molecular sieve is ≥12; further, the SiO2 / Al2O3 molar ratio of the Cu-Fe-SSZ-13 molecular sieve is ≥13; further, the SiO2 / Al2O3 molar ratio of the Cu-Fe-SSZ-13 molecular sieve is ≥13.5.

[0066] According to a specific embodiment of the present invention, the relative crystallinity of the Cu-Fe-SSZ-13 molecular sieve is ≥85%; further, the relative crystallinity of the Cu-Fe-SSZ-13 molecular sieve is ≥90%.

[0067] According to a specific embodiment of the present invention, the pore volume of the Cu-Fe-SSZ-13 molecular sieve is 0.32-0.36 cm 3 / g.

[0068] The present invention also provides a catalyst, which is made from the Cu-Fe-SSZ-13 molecular sieve.

[0069] According to a specific embodiment of the present invention, the preparation method of the catalyst comprises: mixing the Cu-Fe-SSZ-13 molecular sieve with an acid solution to obtain an acidic system, and performing acid exchange; performing hydrothermal ultrastabilization treatment on the acid-exchanged molecular sieve to obtain the catalyst.

[0070] In the preparation method of the above-mentioned catalyst, by using acid as an exchange reagent, the molecular sieve framework can be dealuminated, while maintaining the molecular sieve structure, the silicon-aluminum ratio of the Cu-Fe-SSZ-13 catalyst is effectively improved; the increase in the silicon-aluminum ratio is beneficial to improving the hydrothermal stability of the catalyst, and hydrothermal stability is one of the important properties of catalysts suitable for diesel vehicle exhaust treatment.

[0071] In the preparation method of the above-mentioned catalyst, the mass ratio of the dry basis of the Cu-Fe-SSZ-13 molecular sieve to the acid solution can be 1:5-20, specifically 1:5, 1:10, 1:15, 1:20 and other specific values, as well as a range with any two of the above-mentioned specific values ​​as endpoints; the pH value of the acidic system is 1.0-4.0, specifically 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0 and other specific values, as well as a range with any two of the above-mentioned specific values ​​as endpoints.

[0072] In the preparation method of the above-mentioned catalyst, the temperature of the acid exchange is 10-100°C, and can be specifically 10°C, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C and the like, as well as a range with any two of the above-mentioned specific values ​​as endpoints; the time of the acid exchange is 0.5h-5h, and can be specifically 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h°C and the like, as well as a range with any two of the above-mentioned specific values ​​as endpoints.

[0073] In the preparation method of the above-mentioned catalyst, the temperature of the hydrothermal ultra-stable treatment is generally 400-850°C, and can be specifically 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, 800°C, 850°C and other specific values, as well as a range with any two of the above specific values ​​as endpoints; further, the temperature of the hydrothermal ultra-stable treatment can be 500-800°C.

[0074] In the preparation method of the above-mentioned catalyst, the time of the hydrothermal overheating treatment is generally 0.5-100h, and specifically can be 0.5h, 1h, 5h, 10h, 30h, 50h, 70h, 90h, 100h and other specific values, as well as a range with any two of the above specific values ​​as endpoints; further, the time of the hydrothermal overheating treatment can be 20-60h.

[0075] In the above-mentioned method for preparing the catalyst, the hydrothermal ultra-stabilization treatment is carried out in a 5-100 vol% water vapor atmosphere. Further, the hydrothermal ultra-stabilization treatment is carried out in a 7-50 vol% water vapor atmosphere.

[0076] According to a specific embodiment of the present invention, the preparation method of the above catalyst may specifically include:

[0077] Step 1, mixing the Cu-Fe-SSZ-13 molecular sieve with an acidic solution for acid treatment to obtain an acidic system, adjusting the pH value to be in the range of 1.0-4.0, slurrying according to the mass ratio of Cu-Fe-SSZ-13 molecular sieve (dry basis): acidic solution = 1: (5-20), stirring and exchanging at 10-100° C. for 0.5-5h, and obtaining the acid-treated molecular sieve;

[0078] Step 2, subjecting the acid-treated molecular sieve to hydrothermal ultra-stabilization treatment, including placing the acid-treated molecular sieve in a hydrothermal furnace at 400-850° C., calcining it in a 5-100 vol% water vapor atmosphere for 0.5 h-100 h, tableting, and sieving to obtain a 40-60 mesh catalyst.

[0079] In the above-mentioned method for preparing the catalyst, the acid solution may include aqueous solutions of the following reagents: one or a combination of two or more of hydrochloric acid, sulfuric acid, nitric acid, acetic acid, oxalic acid, citric acid and carbonic acid.

[0080] The present invention also provides the use of the above catalyst in DeNOx reaction. The catalyst prepared by the Cu-Fe-SSZ-13 molecular sieve provided by the present invention has high NO in the selective catalytic reduction reaction of ammonia. x The conversion rate and high selectivity of generating N2. Furthermore, under the condition of the same CuO content, the copper-containing SSZ-13 molecular sieve with added iron is more active at low temperature than the SSZ-13 molecular sieve containing only copper.

[0081] The beneficial effects of the present invention include:

[0082] 1. The present invention provides a method for preparing a Cu-Fe-SSZ-13 catalyst by an in-situ synthesis method. The Cu-Fe-SSZ-13 molecular sieve obtained by the method has the characteristics of high acid content and large specific surface area. When used for DeNOx reaction, the synergistic effect of Cu-Fe not only improves the low-temperature (150-200°C) DeNOx activity, but also improves the high-temperature (500-600°C) DeNOx activity, so that the catalyst has high selectivity and conversion rate under both low and high temperature conditions. On the other hand, under the action of copper amine (Cu-polyamine), the active components Cu and Fe can be stably dispersed inside the molecular sieve, and the load is more firmly, reducing the active component release rate, improving the diffusion of reactants, enhancing the accessibility of activity, and reducing the occurrence of side reactions, and having good activity and selectivity.

[0083] 2. When the highly active Cu-Fe-SSZ-13 molecular sieve provided by the present invention is used as a catalyst for DeNOx reaction, the Cu-Fe in the molecular sieve promotes and cooperates with each other, and can obtain a reduced NO with both high low temperature and high temperature. X On the other hand, the catalyst can improve the diffusion of reactants, enhance the accessibility of activity, reduce the occurrence of side reactions, and has good activity and selectivity.

[0084] 3. The preparation method provided by the present invention is a method for preparing aluminosilicate SSZ-13 containing copper atoms and iron atoms bonded to the framework by a one-pot method. The method can obtain a molecular sieve product with a wide Si / Al ratio, and the Cu and Fe contents in the product are controllable. The method significantly improves the physical and chemical properties of the Cu-SSZ-13 material, and since the preparation method of the present invention only requires a single OSDA, the existing preparation method of the molecular sieve is simplified, and the use of ammonia is also avoided.

[0085] In addition, the preparation method directly prepares Fe-NaY molecular sieve as Fe source and aluminum source through ion exchange method, and directly introduces Cu-Fe ions into SSZ-13 molecular sieve to prepare Cu-Fe-SSZ-13 molecular sieve catalyst. The catalyst has the characteristics of uniform distribution of copper ions and iron ions, and no agglomeration of CuO and Fe2O3. The combination of Cu, Fe and Al in the molecular sieve framework forms highly active metal sites, which improves the conversion rate and selectivity of the catalyst.

[0086] 4. The Cu-Fe-SSZ-13 molecular sieve provided by the present invention can promote the iron metal to enter the molecular sieve framework by adding part of iron in the process of synthesizing the molecular sieve directing agent, so as to be in a more stable binding mode and form more catalytic active sites, thereby preventing the iron in the Cu-Fe-SSZ-13 molecular sieve from being easily lost during the molecular sieve activation process.

[0087] 5. The preparation method provided by the present invention adopts the form of copper amine complex to add copper element, which can obtain a more stable binding structure of copper atoms, making the Cu binding more stable and not easy to lose. BRIEF DESCRIPTION OF THE DRAWINGS

[0088] Figure 1 These are the XRD diagrams of Cu-Fe-SSZ-13-1 and Cu-SSZ-13-1* molecular sieves.

[0089] Figure 2 This is the SEM image of Cu-Fe-SSZ-13-1 molecular sieve.

[0090] Figure 3 This is the NH3-TPD result diagram of Cu-Fe-SSZ-13-1 and Cu-SSZ-13-1* molecular sieves. DETAILED DESCRIPTION

[0091] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0092] The characterization and testing methods used in the present invention are as follows:

[0093] XRD characterization was performed using Shimadzu X-ray powder diffractometer with the following test conditions: CuKα radiation, Ni filter, tube voltage 30KV, tube current 40Ma, step width 0.02, scanning range 5-35°, and scanning rate 5° / min.

[0094] BET characterization was performed using the ipore600 analyzer from Lihua Lianke. 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 Analysis Methods (RIPP Test Methods)), edited by Yang Cuiding et al., Science Press, published in 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 determined using the BET method.

[0095] NH3-TPD characterization was performed using ichem700 from Lihua Lianke. The NH3-TPD analysis method was used to qualitatively determine the amount of strong acid. The specific operation of the NH3-TPD analysis method was as follows: the Cu-SSZ-13 molecular sieve was tableted, crushed, and sieved, and 20-40 mesh particles were dried for standby use to obtain the sample to be tested. During the experiment, 0.15 g of the dried sample to be tested was accurately weighed and loaded into a quartz tube. The zeolite bed was supported by a quartz sand bed layer under the zeolite bed layer and covered by a quartz sand bed layer on the top, so that the zeolite bed layer was located at the thermocouple position. The sample was heated to 550°C for activation for 3 hours in a He atmosphere, cooled to room temperature, adsorbed 100% ammonia for 20 minutes, and then heated to 100°C for a constant temperature. After the baseline was stable, the temperature was increased to 650°C at a heating rate of 10°C / min and the ammonia desorption signal was collected and maintained for 20 minutes. The desorption temperature of ammonia can be used to reflect the acid strength of the molecular sieve catalyst. The higher the desorption temperature of ammonia, the stronger the corresponding acid strength. At the same time, a TCD detector is used to detect changes in gas components. The instrument automatically integrates the total acid content and the strong acid content. Among them, the acid center of the strong acid is the acid center corresponding to the NH3 desorption temperature greater than 300°C.

[0096] The sample morphology was analyzed by SEM. The scanning electron microscope model was REgulus8100 from HITACHI, Japan. The fully dried sample was fixed on the sample tray with conductive glue and vacuumed to 10 -4 After Pa, physical gold plating is performed for 7-10 minutes, and then scanning test is performed.

[0097] Principle of fluorescence spectroscopy (X-ray fluorescence): X-rays are electromagnetic waves with short wavelengths and high energy. When X-rays are used to irradiate a substance, in addition to scattering and absorption, they will also cause the electrons in the atoms to be ionized. The electrons in the inner orbit will leave the atom to form a vacancy, making the atom in an "excited metastable state". In this way, the outer electrons will automatically jump to the inner layer to fill this vacancy, thereby emitting X-rays of a certain energy. Because its wavelength and energy are different from the original irradiated X-rays, scientists call it secondary X-rays, also known as X-ray fluorescence. The wavelength of X-ray fluorescence often depends on the type of elements in the substance. Each element has its own specific X-ray fluorescence energy and wavelength, so the type of elements contained in the substance can be distinguished. At the same time, according to the intensity of the X-ray fluorescence excited by the substance, the content of the elements contained in it can be measured. The advantages of fluorescence spectroscopy analysis are rapidity, convenience and sensitivity. The limitations are that this method determines the surface element composition of the substance, and it is not suitable for measuring elements below atomic number 11 (Na, not included).

[0098] Instrument model: Japan Rigaku Smart lab.

[0099] Relative crystallinity of the sample X i Determination of: X i =X R (∑A i / ΣA R );

[0100] X R - Standard sample (SSZ-13 molecular sieve of China Catalyst New Materials Co., Ltd.: crystallinity 100%;

[0101] ∑A i - The sum of the diffraction peak areas of the sample to be tested;

[0102] ∑A R - The sum of the diffraction peak areas of the standard sample.

[0103] In the following examples and comparative examples, the water glass used has a SiO2 content of 24.03 wt.%, and a Na2O content of 7.26 wt.%.

[0104] Example 1

[0105] This embodiment provides a synthetic Cu-Fe-SSZ-13 molecular sieve, and the preparation method thereof comprises the following steps:

[0106] (1) Preparation of directing agent: weigh 38.2 g of water glass into a beaker, adjust the water bath temperature to 50°C, stir and preheat for 5 min, then add 32.5 g of sodium aluminate solution and mix well; weigh 2 g of Fe(NO3)3·9H2O and dissolve it in 8.4 g of sodium hydroxide solution, then add it to the mixture of water glass and sodium aluminate to form a directing agent precursor, stir and age at 50°C for 5 h to obtain a crystallized directing agent;

[0107] Wherein, the chemical composition of the directing agent precursor is the following molar ratio:

[0108] Fe2O3:Na2O:Al2O3:SiO2:H2O=0.11:25.92:1:15.93:329.74.

[0109] (2) Preparation of gel: 300.5 g of water glass was added to a beaker and placed in a 50° C. water bath and stirred. After 5 min, 6.5 g of 3 mol / L sulfuric acid was added dropwise. After stirring for 30 min, the mixture was allowed to stand at 50° C. for 5 h. 87.2 g of sodium aluminate solution, 72.4 g of a crystallization directing agent, 66.3 g of deionized water, and 4.6 g of Fe(NO3)3·9H2O were added and stirred for 4 h. Thereafter, 186.0 g of aluminum sulfate was slowly added within 20 min. The solution thickened to form a gel-like molecular sieve precursor. The chemical composition of the molecular sieve precursor satisfied the following molar ratio:

[0110] Fe2O3: Na2O: Al2O3: SiO2: H2O=0.10: 2.99: 1: 8.47: 179.32;

[0111] The mass of the crystallization directing agent is 10% of the mass of the molecular sieve precursor; the pH value of the molecular sieve precursor is 11.3;

[0112] The molecular sieve precursor was aged for 6 hours under rapid stirring, and then placed in a 100° C. oven for static crystallization for 72 hours; after crystallization, the precursor was centrifuged, washed, and dried to obtain the Fe-NaY-1 molecular sieve.

[0113] (3) Preparation of copper amine (Cu-polyamine) solution: According to the molar ratio of copper sulfate to tetraethylenepentamine of 1:1, 18% by mass copper sulfate aqueous solution and tetraethylenepentamine were mixed and stirred for 10 minutes to obtain Cu-polyamine for later use.

[0114] (4) Fe-NaY-1 molecular sieve, silica sol, sodium hydroxide solution, organic template N,N,N-trimethyl-1-adamantanammonium hydroxide, copper amine solution, Cu-SSZ-13 molecular sieve seed crystals and deionized water were mixed according to a molar ratio of 0.30Fe2O3:35Na2O:Al2O3:48SiO2:400H2O:15 organic template (OSDA):5Cu-polyamine, and the mixture was stirred at 50°C for 2h to perform a gelation reaction to obtain a gel, wherein the mass of the Cu-SSZ-13 molecular sieve seed crystals was 1.2% of the mass of the gel;

[0115] The obtained gel was dynamically crystallized at 170°C for 42 hours, heated to 530°C at a rate of 3°C / min, and calcined at 530°C for 4 hours to obtain the molecular sieve Cu-Fe-SSZ-13-1.

[0116] The relative crystallinity of the Cu-Fe-SSZ-13-1 molecular sieve sample was measured to be 93%, the SiO2 / Al2O3 molar ratio (hereinafter referred to as silicon-aluminum ratio) was 15.9, and the specific surface area was 786 m 2 / g, pore volume 0.34cm 3 / g, the CuO content is 5.2wt.%, and the Fe2O3 content is 2.3wt.%.

[0117] Example 2

[0118] This embodiment provides a synthetic Cu-Fe-SSZ-13 molecular sieve, and the preparation method thereof comprises the following steps:

[0119] (1) Preparation of directing agent:

[0120] Weigh 46.2g of water glass into a beaker, adjust the water bath temperature to 50°C, stir and preheat for 5 minutes, then add 34.5g of sodium aluminate solution and mix evenly; weigh 0.8g of Fe(NO3)3·9H2O and dissolve it in 7.4g of sodium hydroxide solution, after Fe(NO3)3·9H2O is dissolved, add the solution to the mixture of water glass and sodium aluminate to form a directing agent precursor, stir and age at 50°C for 5h to obtain an iron-containing crystallization directing agent;

[0121] Wherein, the chemical composition of the directing agent precursor is the following molar ratio:

[0122] Fe2O3:Na2O:Al2O3:SiO2:H2O=0.06:19.65:1:18.11:321.86.

[0123] (2) Gel preparation:

[0124] 320.0g of water glass was added to a beaker and placed in a 40°C water bath and stirred. After 5 minutes, 8.7g of 3mol / L sulfuric acid was added dropwise. After stirring for 30 minutes, the mixture was aged at 40°C for 5 hours. 89.8g of sodium aluminate solution, 75.1g of crystallization directing agent, 100.2g of deionized water, and 13.8g of Fe(NO3)3·9H2O were added and stirred for 3 hours. Thereafter, 191.3g of aluminum sulfate was slowly added within 20 minutes. The solution thickened to form a gel-like molecular sieve precursor. The chemical composition of the molecular sieve precursor met the following molar ratios:

[0125] Fe2O3: Na2O: Al2O3: SiO2: H2O=0.22: 2.84: 1: 8.88: 193.21;

[0126] The mass of the crystallization directing agent is 9.5% of the mass of the molecular sieve precursor; the pH value of the molecular sieve precursor is 11.5;

[0127] The molecular sieve precursor was aged for 3 hours under rapid stirring, and then placed in an oven at 103°C for static crystallization for 64 hours; after crystallization, centrifuged, washed, and dried to obtain Fe-NaY-2 molecular sieve.

[0128] (3) Preparation of copper amine (Cu-polyamine) solution: According to the molar ratio of copper sulfate to triethylenetetramine of 1:1, 18% by mass copper sulfate aqueous solution and triethylenetetramine were mixed and stirred for 10 minutes to obtain Cu-polyamine for later use.

[0129] (4) Fe-NaY-2 molecular sieve, silica sol, sodium hydroxide solution, organic template N,N,N-trimethyl-1-adamantanammonium hydroxide, copper amine solution and deionized water were mixed according to a molar ratio of 0.1Fe2O3:41Na2O:Al2O3:48SiO2:400H2O:19 organic template:4Cu-polyamine to obtain a reaction gel, and the reaction was stirred at 60°C for 1.5h to perform a gelation reaction to obtain a gel, wherein the mass of the Cu-SSZ-13 molecular sieve seed crystals was 0.75% of the mass of the gel;

[0130] The obtained gel was dynamically crystallized at 160°C for 45 hours, cooled, filtered, washed and dried after the crystallization, and then heated to 520°C at a rate of 5°C / min and calcined at 520°C for 6 hours to obtain the molecular sieve Cu-Fe-SSZ-13-2.

[0131] The relative crystallinity of the Cu-Fe-SSZ-13-2 molecular sieve sample was measured to be 101%, the silicon-aluminum ratio was 16.4, and the specific surface area was 785 m 2 / g, pore volume 0.34cm 3 / g, the CuO content is 4.9wt.%, and the Fe2O3 content is 1.3wt.%.

[0132] Comparative Example 1

[0133] This comparative example provides a Cu-SSZ-13 molecular sieve, the preparation method of which comprises the following steps:

[0134] (1) Preparation of directing agent: weigh 38.2 g of water glass into a beaker, adjust the water bath temperature to 50°C, stir and preheat for 5 min, then add 32.5 g of sodium aluminate solution and mix well; add 8.4 g of sodium hydroxide solution to the mixture of water glass and sodium aluminate to form a directing agent precursor, stir and age at 50°C for 5 h to obtain a crystallized directing agent;

[0135] Wherein, the chemical composition of the directing agent precursor is the following molar ratio:

[0136] Na2O:Al2O3:SiO2:H2O=24.98:1:15.93:329.74.

[0137] (2) Preparation of gel: 300.5 g of water glass was weighed and placed in 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. After stirring for 30 min, the mixture was allowed to stand at 50° C. for 5 h. 87.2 g of sodium aluminate solution, 72.4 g of a crystallization directing agent, and 66.3 g of deionized water were added. Then, 186.0 g of aluminum sulfate was slowly added within 20 min. The solution thickened to form a gel-like molecular sieve precursor. The chemical composition of the molecular sieve precursor satisfied the following molar ratio:

[0138] Na2O:Al2O3:SiO2:H2O=2.35:1:8.47:179.32;

[0139] The mass of the crystallization directing agent is 10% of the mass of the molecular sieve precursor; the pH value of the molecular sieve precursor is 11.8; the molecular sieve precursor is aged for 6 hours under rapid stirring, placed in a 100° C. oven for static crystallization for 72 hours; after crystallization, centrifugation, washing and drying are performed to obtain the NaY-1* molecular sieve.

[0140] (3) Fe(NO3)3·9H2O, NaY-1* molecular sieve, silica sol, sodium hydroxide solution, organic template N,N,N-trimethyl-1-adamantanammonium hydroxide, copper amine solution (prepared in the same manner as in Example 1, with a molar ratio of copper sulfate to tetraethylenepentamine of 1:1), Cu-SSZ-13 molecular sieve seed crystals and deionized water were mixed in a molar ratio of 0.30Fe2O3:35Na2O:Al2O3:48SiO2:400H2O:15 organic template:5Cu-polyamine, and the mixture was stirred at 50°C for 2h to carry out a gelation reaction to obtain a gel, wherein the mass of the Cu-SSZ-13 molecular sieve seed crystals was 1.2% of the mass of the gel;

[0141] The obtained gel was dynamically crystallized at 170°C for 42 hours, cooled, filtered, washed and dried after the crystallization, and then heated to 530°C at a rate of 3°C / min, and calcined at 530°C for 4 hours to obtain molecular sieve Cu-Fe-SSZ-13-1*. Compared with the method of Example 1, the method of this experiment changed the way of adding the iron source.

[0142] The relative crystallinity of the Cu-Fe-SSZ-13-1* molecular sieve was measured to be 81%, the silicon-aluminum ratio was 13.8, and the specific surface area was 693 m 2 / g, pore volume 0.29cm 3 / g, the CuO content is 3.9wt.%, and the Fe2O3 content is 2.3wt.%.

[0143] Comparative Example 2

[0144] This comparative example provides a Cu-SSZ-13 molecular sieve, the preparation method of which comprises the following steps:

[0145] (1) Preparation of directing agent:

[0146] Weigh 46.2 g of water glass into a beaker, adjust the water bath temperature to 50°C, stir and preheat for 5 minutes, then add 34.5 g of sodium aluminate solution and mix evenly; add 7.4 g of sodium hydroxide solution to the mixture of water glass and sodium aluminate to form a directing agent precursor, stir and age at 50°C for 5 hours to obtain a crystallized directing agent;

[0147] Wherein, the chemical composition of the directing agent precursor is the following molar ratio:

[0148] Na2O:Al2O3:SiO2:H2O=19.71:1:18.11:321.86.

[0149] (2) Gel preparation:

[0150] 320.0g of water glass was added to a beaker and placed in a 40°C water bath and stirred. After 5 minutes, 8.7g of 3mol / L sulfuric acid was added dropwise. After stirring for 30 minutes, the mixture was allowed to stand at 40°C for 5 hours. 89.8g of sodium aluminate solution, 75.1g of a crystallization directing agent, and 100.2g of deionized water were added and stirred for 3 hours. Thereafter, 191.3g of aluminum sulfate was slowly added within 20 minutes. The solution thickened to form a gel-like molecular sieve precursor. The chemical composition of the molecular sieve precursor met the following molar ratios:

[0151] Na2O:Al2O3:SiO2:H2O=3.06:1:8.88:193.21;

[0152] The mass of the crystallization directing agent is 9.5% of the mass of the molecular sieve precursor; the pH value of the molecular sieve precursor is 12.1;

[0153] The molecular sieve precursor was aged for 3 hours under rapid stirring, and then placed in an oven at 103°C for static crystallization for 64 hours; after crystallization, it was centrifuged, washed, and dried to obtain the NaY-2* molecular sieve.

[0154] (3) Preparation of copper amine (Cu-polyamine) solution: According to the molar ratio of copper sulfate to triethylenetetramine of 1:1, 18% by mass copper sulfate aqueous solution and triethylenetetramine were mixed and stirred for 10 minutes to obtain Cu-polyamine for later use.

[0155] (4) mixing NaY-2* molecular sieve, silica sol, sodium hydroxide solution, organic template N,N,N-trimethyl-1-adamantanammonium hydroxide, copper amine solution and deionized water in a molar ratio of 41Na2O:Al2O3:48SiO2:400H2O:19 organic template:4Cu-polyamine to obtain a reaction gel, stirring at 60°C for 1.5h to perform a gelation reaction to obtain a gel, wherein the mass of the Cu-SSZ-13 molecular sieve seed crystals is 0.75% of the mass of the gel;

[0156] The obtained gel was dynamically crystallized at 160°C for 45 hours, cooled, filtered, washed and dried after crystallization, and then heated to 520°C at a rate of 5°C / min and calcined at 520°C for 6 hours to obtain molecular sieve Cu-SSZ-13-2*. Compared with the method of Example 2, the method of this experiment did not add an iron source.

[0157] The relative crystallinity of the Cu-SSZ-13-2* molecular sieve sample was measured to be 79%, the silicon-aluminum ratio was 14.4, and the specific surface area was 702 m 2 / g, pore volume 0.31cm 3 / g, CuO content is 4.1wt.%.

[0158] Comparative Example 3

[0159] This comparative example provides a Cu-Fe-SSZ-13 molecular sieve, the preparation method of which comprises the following steps:

[0160] (1) Preparation of directing agent:

[0161] Weigh 46.2g of water glass into a beaker, adjust the water bath temperature to 50°C, stir and preheat for 5 minutes, then add 34.5g of sodium aluminate solution and mix evenly; weigh 0.8g of Fe(NO3)3·9H2O and dissolve it in 7.4g of sodium hydroxide solution, after Fe(NO3)3·9H2O is dissolved, add the solution to the mixture of water glass and sodium aluminate to form a directing agent precursor, stir and age at 50°C for 5h to obtain an iron-containing crystallization directing agent;

[0162] Wherein, the chemical composition of the directing agent precursor is the following molar ratio:

[0163] Fe2O3:Na2O:Al2O3:SiO2:H2O=0.06:19.65:1:18.11:321.86.

[0164] (2) Gel preparation:

[0165] 320.0g of water glass was added to a beaker and placed in a 40°C water bath and stirred. After 5 minutes, 8.7g of 3mol / L sulfuric acid was added dropwise. After stirring for 30 minutes, the mixture was aged at 40°C for 5 hours. 89.8g of sodium aluminate solution, 75.1g of crystallization directing agent, 100.2g of deionized water, and 13.8g of Fe(NO3)3·9H2O were added and stirred for 3 hours. Thereafter, 191.3g of aluminum sulfate was slowly added within 20 minutes. The solution thickened to form a gel-like molecular sieve precursor. The chemical composition of the molecular sieve precursor met the following molar ratios:

[0166] Fe2O3: Na2O: Al2O3: SiO2: H2O=0.22: 2.84: 1: 8.88: 193.21;

[0167] The mass of the crystallization directing agent is 9.5% of the mass of the molecular sieve precursor; the pH value of the molecular sieve precursor is 11.6;

[0168] The molecular sieve precursor was aged for 3 hours under rapid stirring, and then placed in an oven at 103°C for static crystallization for 64 hours; after crystallization, centrifuged, washed, and dried to obtain Fe-NaY-3* molecular sieve.

[0169] (3) Fe-NaY-3* molecular sieve, silica sol, sodium hydroxide solution, organic template N,N,N-trimethyl-1-adamantanammonium hydroxide, copper sulfate solution and deionized water were mixed according to the molar ratio of 0.37CuO:0.1Fe2O3:41Na2O:Al2O3:48SiO2:400H2O:19 organic template to obtain a reaction gel, and the reaction was carried out by stirring at 60°C for 1.5h to obtain a gel, wherein the mass of the Cu-SSZ-13 molecular sieve seed crystals was 0.75% of the mass of the gel;

[0170] The obtained gel was dynamically crystallized at 160°C for 45 hours, cooled, filtered, washed and dried after crystallization, and then heated to 520°C at a rate of 5°C / min and calcined at 520°C for 6 hours to obtain molecular sieve Cu-Fe-SSZ-13-3*. Compared with Example 2, this experiment changed the way of adding the copper source.

[0171] The relative crystallinity of the Cu-Fe-SSZ-13-3* molecular sieve sample was measured to be 80%, the silicon-aluminum ratio was 14.5, and the specific surface area was 711 m 2 / g, pore volume 0.32cm 3 / g, the CuO content is 4.1wt.%, and the Fe2O3 content is 1.2wt.%.

[0172] Comparative Example 4

[0173] This comparative example provides a Cu-SSZ-13 molecular sieve, the preparation method of which comprises the following steps:

[0174] (1) Preparation of directing agent:

[0175] Weigh 46.2 g of water glass into a beaker, adjust the water bath temperature to 50°C, stir and preheat for 5 minutes, then add 34.5 g of sodium aluminate solution and mix evenly; add 7.4 g of sodium hydroxide solution to the mixture of water glass and sodium aluminate to form a directing agent precursor, stir and age at 50°C for 5 hours to obtain a crystallized directing agent;

[0176] Wherein, the chemical composition of the directing agent precursor is the following molar ratio:

[0177] Na2O:Al2O3:SiO2:H2O=19.71:1:18.11:321.86.

[0178] (2) Gel preparation:

[0179] 320.0g of water glass was added to a beaker and placed in a 40°C water bath and stirred. After 5 minutes, 8.7g of 3mol / L sulfuric acid was added dropwise. After stirring for 30 minutes, it was allowed to stand at 40°C for 5 hours. 89.8g of sodium aluminate solution, 75.1g of crystallization directing agent, and 100.2g of deionized water were added and stirred for 3 hours. Thereafter, 191.3g of aluminum sulfate was slowly added within 20 minutes. The solution thickened to form a gel-like molecular sieve precursor. The chemical composition of the molecular sieve precursor met the following molar ratios:

[0180] Na2O:Al2O3:SiO2:H2O=3.06:1:8.88:193.21;

[0181] The mass of the crystallization directing agent is 9.5% of the mass of the molecular sieve precursor; the pH value of the molecular sieve precursor is 11.8;

[0182] The gel reaction product was aged for 3 hours under rapid stirring, and then placed in an oven at 103°C for static crystallization for 64 hours; after crystallization, it was centrifuged, washed, and dried to obtain NaY-4* molecular sieve.

[0183] (3) Preparation of copper amine (Cu-polyamine) solution: According to the molar ratio of copper sulfate to triethylenetetramine of 1:1, 18% by mass copper sulfate aqueous solution and triethylenetetramine were mixed and stirred for 10 minutes to obtain Cu-polyamine for later use.

[0184] (4) mixing NaY-4* molecular sieve, silica sol, sodium hydroxide solution, organic template N,N,N-trimethyl-1-adamantanammonium hydroxide, copper amine solution and deionized water in a molar ratio of 41Na2O:Al2O3:48SiO2:400H2O:19 organic template:0.3Cu-polyamine to obtain a reaction gel, stirring at 60°C for 1.5h to perform a gelation reaction to obtain a gel, wherein the mass of the Cu-SSZ-13 molecular sieve seed crystals is 0.75% of the mass of the gel;

[0185] The obtained gel was dynamically crystallized at 160°C for 45 hours, cooled, filtered, washed and dried after crystallization, and then heated to 520°C at a rate of 5°C / min and calcined at 520°C for 6 hours to obtain molecular sieve Cu-SSZ-13-4*. Compared with Example 2, no iron source was added in this experiment and the amount of copper source added was reduced.

[0186] The relative crystallinity of the Cu-SSZ-13-4* molecular sieve sample was measured to be 83%, the silicon-aluminum ratio was 15.8, and the specific surface area was 678 m 2 / g, pore volume 0.28cm 3 / g, CuO content is 2.3wt.%.

[0187] Comparative Example 5

[0188] This comparative example provides a Fe-SSZ-13 molecular sieve, the preparation method of which comprises the following steps:

[0189] (1) Preparation of directing agent: weigh 38.2 g of water glass into a beaker, adjust the water bath temperature to 50°C, stir and preheat for 5 min, then add 32.5 g of sodium aluminate solution and mix well; weigh 2 g of Fe(NO3)3·9H2O and dissolve it in 8.4 g of sodium hydroxide solution, then add it to the mixture of water glass and sodium aluminate to form a directing agent precursor, stir and age at 50°C for 5 h to obtain a crystallized directing agent;

[0190] Wherein, the chemical composition of the directing agent precursor is the following molar ratio:

[0191] Fe2O3:Na2O:Al2O3:SiO2:H2O=0.11:25.92:1:15.93:329.74.

[0192] (2) Preparation of gel: 300.5 g of water glass was added to a beaker and placed in a 50° C. water bath and stirred. After 5 min, 6.5 g of 3 mol / L sulfuric acid was added dropwise. After stirring for 30 min, the mixture was allowed to stand at 50° C. for 5 h. 87.2 g of sodium aluminate solution, 72.4 g of a crystallization directing agent, 66.3 g of deionized water, and 4.6 g of Fe(NO3)3·9H2O were added and stirred for 4 h. Thereafter, 186.0 g of aluminum sulfate was slowly added within 20 min. The solution thickened to form a gel-like molecular sieve precursor. The chemical composition of the molecular sieve precursor satisfied the following molar ratio:

[0193] Fe2O3: Na2O: Al2O3: SiO2: H2O=0.10: 2.99: 1: 8.47: 179.32;

[0194] The mass of the crystallization directing agent is 10% of the mass of the molecular sieve precursor; the pH value of the molecular sieve precursor is 11.3;

[0195] The molecular sieve precursor was aged for 6 hours under rapid stirring, and then placed in a 100° C. oven for static crystallization for 72 hours; after crystallization, the precursor was centrifuged, washed, and dried to obtain the Fe-NaY-5* molecular sieve.

[0196] (3) Fe-NaY-5* molecular sieve, silica sol, sodium hydroxide solution, organic template N,N,N-trimethyl-1-adamantanammonium hydroxide, Cu-SSZ-13 molecular sieve seed crystals and deionized water were mixed according to the molar ratio of 0.30Fe2O3:35Na2O:Al2O3:48SiO2:400H2O:15 organic template, and the mixture was stirred at 50°C for 2h to perform gelation reaction to obtain a gel, wherein the mass of the Cu-SSZ-13 molecular sieve seed crystals accounted for 1.2% of the mass of the gel;

[0197] The obtained gel was dynamically crystallized at 170°C for 42 hours, cooled, filtered, washed and dried after the crystallization, and then heated to 530°C at a rate of 3°C / min, and calcined at 530°C for 4 hours to obtain the molecular sieve Fe-SSZ-13-5*. Compared with Example 1, no copper source was added in this experiment.

[0198] The relative crystallinity of the Fe-SSZ-13-5* molecular sieve sample was measured to be 93%, the silicon-aluminum ratio was 15.7, and the specific surface area was 785 m 2 / g, pore volume 0.34cm 3 / g, Fe2O3 content is 1.2wt.%.

[0199] The structural parameters of the above molecular sieve samples are summarized in Table 1.

[0200] Table 1

[0201] <![CDATA[Molar ratio of SiO2 / Al2O3]]> <![CDATA[Specific surface area, m 2 / g]]> <![CDATA[Pore volume, cm 3 / g]]> CuO, wt.% <![CDATA[Fe2O3,wt.%]]> Example 1 15.9 786 0.34 5.2 2.3 Comparative Example 1 13.8 693 0.29 3.9 2.3 Comparative Example 5 15.7 785 0.34 0 1.2 Example 2 16.4 785 0.34 4.9 1.3 Comparative Example 2 14.4 702 0.31 4.1 0 Comparative Example 3 14.5 711 0.32 4.1 1.2 Comparative Example 4 15.8 678 0.28 2.3 0

[0202] According to Table 1, from the comparison of Example 1 and Comparative Example 1, and the comparison of Example 2, Comparative Example 2 and Comparative Example 4, it can be seen that by adding an iron source during the preparation process and controlling the method of adding the iron source, it is beneficial to increase the specific surface area, pore volume and Cu content in the molecular sieve.

[0203] From the comparison between Example 1 and Comparative Example 5, it can be seen that by adding a copper source during the preparation process, the specific surface area and pore volume of the molecular sieve can be increased, and the Fe content in the molecular sieve can be increased.

[0204] From the comparison between Comparative Example 2 and Comparative Example 4, it can be seen that by controlling the amount of copperamine added, not only the Cu content in the molecular sieve can be regulated, but also the specific surface area and pore volume of the molecular sieve can be regulated.

[0205] From the comparison between Example 2 and Comparative Example 3, it can be seen that adding the copper source in the form of Cu-polyamine during the preparation process is beneficial to increasing the specific surface area of ​​the molecular sieve and the Cu content in the molecular sieve.

[0206] Example 3

[0207] This embodiment provides a method for preparing a catalyst, comprising:

[0208] Take 20g of the Cu-Fe-SSZ-13-1 molecular sieve prepared in Example 1, then add 1mol / L HCl solution to treat it with acid, and slurry it according to the mass ratio of molecular sieve (dry basis): acid solution = 1:10, and the pH value of the slurry is 2.5; stir and exchange at 90℃ for 1h; perform hydrothermal ultra-stabilization treatment on the acid-treated molecular sieve, place the acid-treated molecular sieve in a hydrothermal furnace at 650℃, and roast it in a 10% (volume) water vapor atmosphere for 50h, and finally obtain a 40-60 mesh Cat.-1 catalyst through tableting and screening. The Cu and Fe contents of the catalyst samples before and after hydrothermal treatment were measured respectively to detect the loss rates of Cu and Fe, which were used to investigate the hydrothermal stability of Cu and Fe metals, and the results are shown in Table 2.

[0209] According to the above method, a catalyst was prepared by replacing the Cu-Fe-SSZ-13-1 molecular sieve in Example 1 with the Cu-Fe-SSZ-13-2 molecular sieve in Example 2, which was recorded as catalyst Cat.-2; and the hydrothermal stability of Cu and Fe of the catalyst was investigated. The results are shown in Table 2.

[0210] Comparative Example 6

[0211] This comparative example provides a method for preparing a catalyst, comprising:

[0212] Take 20g of Cu-Fe-SSZ-13-1*, Cu-SSZ-13-2*, Cu-Fe-SSZ-13-3*, Cu-SSZ-13-4*, Fe-SSZ-13-5* molecular sieves prepared in Comparative Example 1, then add 1mol / L HCl solution to acid-treat them, and slurry them according to the mass ratio of molecular sieve (dry basis): acid solution = 1:10, and the pH value of the slurry is 2.5; stir and exchange at 90°C for 1h; hydrothermally treat the molecular sieves after acid treatment, place the molecular sieves after acid treatment in a hydrothermal furnace at 650°C, and roast them in a 10% (volume) water vapor atmosphere for 50h, and finally press and screen to obtain a 40-60 mesh Cat.-3 catalyst. The Cu and Fe contents of the catalyst samples before and after hydrothermal treatment were measured respectively to detect the loss rates of Cu and Fe, which were used to investigate the hydrothermal stability of Cu and Fe metals, and the results are shown in Table 2.

[0213] According to the above method, the Cu-SSZ-13-2*, Cu-Fe-SSZ-13-3*, Cu-SSZ-13-4*, and Fe-SSZ-13-5* molecular sieves prepared in Comparative Examples 2-5 were used to replace the Cu-Fe-SSZ-13-1* prepared in Comparative Example 1, respectively, and were recorded as catalysts Cat.-4, Cat.-5, Cat.-6, and Cat.-7; and the hydrothermal stability of the Cu and Fe catalysts was investigated. The results are shown in Table 2 (the "--" in Table 2 represents that the data is not available, and the "strong acid content" is the ratio of the strong acid amount to the total acid amount).

[0214] Table 2

[0215]

[0216] It can be seen from Table 2 that the hydrothermal stability of the active metals Cu and Fe in the catalysts of Examples 1 and 2 is significantly better than that of the catalysts of Comparative Examples 1 to 5.

[0217] Furthermore, by comparing Example 1 with Comparative Example 1, it can be seen that by controlling the addition method of the iron source during the preparation of the molecular sieve, it is not only beneficial to reduce the Fe loss rate in the molecular sieve and improve the Fe hydrothermal stability, but also beneficial to reduce the Cu loss rate in the molecular sieve and improve the Cu hydrothermal stability;

[0218] By comparing Example 1 with Comparative Example 5, it can be seen that by adding a copper source during the preparation of the molecular sieve, it is beneficial to reduce the Fe loss rate in the molecular sieve and improve the Fe hydrothermal stability;

[0219] By comparing Example 2 with Comparative Example 2 and Comparative Example 4, it can be seen that by adding an iron source to the molecular sieve raw material, it is beneficial to reduce the Cu loss rate in the molecular sieve and improve the Cu hydrothermal stability;

[0220] By comparing Example 2 with Comparative Example 3, it can be seen that by adding a copper source in the form of Cu-polyamine in the molecular sieve, it is not only beneficial to reduce the Cu loss rate in the molecular sieve and improve the Cu hydrothermal stability, but also beneficial to reduce the Fe loss rate in the molecular sieve and improve the Fe hydrothermal stability.

[0221] Test Example 1

[0222] This test example provides a performance test of the above catalyst.

[0223] The catalysts Cat.-1 to Cat.-7 obtained in Example 3 and Comparative Example 6 were used for NH3-SCR reaction. The reaction gas NO X The volume fraction of NH3 is 300ppm, the volume fraction of O2 is 10%, the volume fraction of water vapor is 10%, and N2 is used as the balance gas. The space velocity is 80000h -1 ; The evaluation results are shown in Table 3.

[0224] The NOx conversion rate and N2 selectivity are calculated according to equations (1) and (2) respectively:

[0225]

[0226] Wherein, the subscripts in and out represent the volume fractions of the gas inlet and outlet, respectively, %, specifically:

[0227] [NO x ] in Indicates NO x Volume fraction of inlet, %;

[0228] [NO x ] out Indicates NO x Volume fraction of outlet, %;

[0229] [N2O] out is the outlet volume fraction of N2O, %;

[0230] [NO2] out is the outlet volume fraction of NO2, %;

[0231] [NH3] in is the inlet volume fraction of NH3, %;

[0232] [NH3] out is the outlet volume fraction of NH3, %.

[0233] Table 3

[0234]

[0235] It can be seen from Table 3 that Cat.1 and Cat.2 not only exhibit excellent low-temperature activity, but also excellent high-temperature activity, and their comprehensive performance is significantly better than Cat.3 to Cat.7. This result shows that by adding iron to the SSZ-13 molecular sieve and adding Cu in the form of Cu-polyamine, the low-temperature activity and high-temperature activity of the molecular sieve can be effectively improved.

[0236] Figure 1 The XRD patterns of the molecular sieve sample of Example 1 (Cu-Fe-SSZ-1) and the molecular sieve sample of Comparative Example 1 (Cu-SSZ-13-2*) are shown in Table 1. Figure 1 It can be seen that both molecular sieve samples maintain the CHA topology of the SSZ-13 microporous molecular sieve without generating impurity crystals. Furthermore, the peak intensity of the Cu-Fe-SSZ-13-1 molecular sieve of Example 1 is significantly better than that of the Cu-SSZ-13-1* molecular sieve of Comparative Example 2, indicating that the Cu-Fe-SSZ-13-1 molecular sieve has a higher relative crystallinity.

[0237] Figure 2 This is a SEM photo of the Cu-Fe-SSZ-13-1 molecular sieve sample of Example 1. Figure 2 It can be seen that the molecular sieve sample has a cubic morphology, regular crystal shape, relatively intact crystal growth, uniform grain size and good dispersion.

[0238] Figure 3 The NH3-TPD characterization test results of the molecular sieve sample of Example 1 (Cu-Fe-SSZ-1) and the molecular sieve sample of Comparative Example 1 (Cu-SSZ-13-1*) are shown in FIG. Figure 3 It can be seen that Cu-Fe-SSZ-13-1 and Cu-SSZ-13-1* molecular sieves have similar characteristics, mainly two desorption peaks, concentrated at 175℃ and 320℃. The peak at 175℃ is weakly adsorbed NH3, and the peak at 320℃ is NH3 produced by adsorption on strong acid sites (referring to medium and strong acidity). By comparing the NH3 desorption peaks of Cu-Fe-SSZ-13-1 and Cu-SSZ-13-2* molecular sieves at different temperatures, it can be found that the peak intensity of Cu-Fe-SSZ-13-1 molecular sieve at 175℃ and 320℃ is significantly better than that of Cu-SSZ-13-2* molecular sieve, which indicates that Cu-Fe-SSZ-13-1 molecular sieve has stronger NH3 desorption ability and has more weak acid and medium-strong acid.

[0239] In addition, from Figure 3It can be calculated that the acidic center corresponding to the acidic center with NH3 adsorption temperature above 300°C is a strong acid, and the ratio of strong acid to total acid of the molecular sieve sample of Example 1 is 59%, while the ratio of strong acid to total acid of the molecular sieve sample of Comparative Example 1 is 38%. It can be seen that by introducing copper and iron in a suitable manner, the acidity of the SSZ-13 molecular sieve can be significantly improved, thereby improving the catalytic activity of the molecular sieve.

Claims

1. A method for preparing a Cu-Fe-SSZ-13 molecular sieve, the method comprising: S1, mixing a first iron source, a first silicon source, a first aluminum source and water to form a directing agent precursor, and aging to obtain a crystallization directing agent; S2, mixing the crystallization directing agent, the second silicon source, the second aluminum source, the second iron source and water to obtain a molecular sieve precursor, aging and crystallizing to obtain a Fe-NaY molecular sieve; S3, mixing the Fe-NaY molecular sieve, the third silicon source, Cu-polyamine, OSDA, water, and Cu-SSZ-13 molecular sieve seed crystals to obtain a reaction gel, crystallizing, and calcining to obtain the Cu-Fe-SSZ-13 molecular sieve.

2. The preparation method according to claim 1, wherein The chemical composition of the directing agent precursor satisfies the following molar ratio: Fe2O3:Al2O3=(0.01-0.5):1; Preferably, the chemical composition of the directing agent precursor satisfies the following molar ratio: Fe2O3: Na2O: Al2O3: SiO2: H2O=(0.01-0.5): (8-30): 1: (8-30): (150-450); Preferably, the chemical composition of the directing agent precursor satisfies the following molar ratio: Fe2O3:Al2O3=(0.05-0.3):

1.

3. The preparation method according to claim 1, wherein In S1, the aging temperature is 0-80°C, and the aging time is 1-50h; Preferably, in S1, the aging temperature is 15-65°C; Preferably, in S1, the aging time is 2-20 hours.

4. The preparation method according to claim 1, wherein In S2, the chemical composition of the molecular sieve precursor satisfies the following molar ratio: Fe2O3:Al2O3=(0.01-0.5):1; Preferably, the chemical composition of the molecular sieve precursor satisfies the following molar ratio: Fe2O3: Na2O: Al2O3: SiO2: H2O=(0.01-0.5): (1-6): 1: (8-30): (100-350); The mass of the crystallization directing agent is 1%-50% of the mass of the molecular sieve precursor; More preferably, the mass of the crystallization directing agent is 3%-25% of the mass of the molecular sieve precursor; More preferably, the pH value of the molecular sieve precursor is 11-13.

5.

5. The preparation method according to claim 1, wherein In S2, the aging temperature is 10-80°C, and the aging time is 0.5-15h.

6. The preparation method according to claim 1, wherein In S2, the crystallization temperature is 80-140° C., and the crystallization time is 24-140 h; Preferably, the crystallization temperature is 85-120°C; Preferably, the crystallization time is 30-100 hours.

7. The preparation method according to claim 1, wherein In S3, the chemical composition of the reaction gel satisfies the following molar ratio: Al2O3:Cu-polyamine=1:(1-20); and / or, Fe2O3:Al2O3=0.005-0.3; The chemical composition of the reaction gel satisfies the following molar ratio: Preferably, Fe2O3:Na2O:Al2O3:SiO2:H2O:OSDA:Cu-polyamine=(0.005-0.3):(5-50):1:(10-100):(300-1000):(5-20):(1-20); The mass of the Cu-SSZ-13 molecular sieve seed crystals is 1%-10% of the mass of the reaction gel.

8. The preparation method according to claim 1, wherein In S3, the crystallization temperature is 100-200° C., and the crystallization time is 24-80 hours.

9. The preparation method according to claim 1, wherein: In S3, the calcination process includes: heating to 300-700°C and keeping the temperature for 1-10 hours for calcination; Preferably, the heating rate is 1-30°C / min; more preferably, the heating rate is 3-8°C / min.

10. The preparation method according to claim 1, wherein: The first silicon source and the second silicon source independently include water glass and / or silica sol; And / or, the first aluminum source and the second aluminum source independently include one or a combination of two or more of pseudo-boehmite, sodium aluminate, aluminum sulfate, aluminum nitrate and aluminum chloride; And / or, the first iron source and the second iron source independently include one or a combination of two or more of ferric nitrate, ferric chloride, ferrous chloride and ferric hydroxide; And / or, the third silicon source includes one or a combination of two or more of water glass, silica sol, white carbon black, tetramethyl orthosilicate, tetraethyl orthosilicate, tetrapropyl orthosilicate, and tetrabutyl orthosilicate; and / or, the OSDA comprises one of N,N,N-trimethyl-1-adamantanammonium or benzyltrimethylammonium cationic compounds; And / or, the Cu-polyamine is a complex of Cu and a polyamine, the molar ratio of Cu to the polyamine of the Cu-polyamine is (0.9-1.1):1, preferably 1:1, and the polyamine includes one or a combination of two or more of a primary amine, a secondary amine, and a tertiary amine; preferably, the polyamine includes one or a combination of two or more of tetraethylenepentamine, triethylenetetramine, 1,4,8,11-tetraazacyclotetradecane, and 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane.

11. A Cu-Fe-SSZ-13 molecular sieve obtained by the preparation method according to any one of claims 1 to 10.

12. The Cu-Fe-SSZ-13 molecular sieve according to claim 11, wherein: Taking the total mass of the molecular sieve as 100%, the mass of the element is calculated as the mass of the oxide, the mass content of the Cu element in the Cu-Fe-SSZ-13 molecular sieve is 0.1%-10%; the mass content of the Fe element in the Cu-Fe-SSZ-13 molecular sieve is 0.1%-3%; Preferably, the strong acid content of the Cu-Fe-SSZ-13 molecular sieve is 40%-70% of the total acid content; Preferably, the mass content of the Cu element in the Cu-Fe-SSZ-13 molecular sieve is 1.0%-8.0%; Preferably, the mass content of the Fe element in the Cu-Fe-SSZ-13 molecular sieve is 0.3%-1.5%.

13. The Cu-Fe-SSZ-13 molecular sieve according to claim 11, wherein: The specific surface area of ​​the Cu-Fe-SSZ-13 molecular sieve is ≥680m 2 / g; and / or, the pore volume of the Cu-Fe-SSZ-13 molecular sieve is 0.32-0.36cm 3 / g; Preferably, the specific surface area of ​​the Cu-Fe-SSZ-13 molecular sieve is ≥700m 2 / g.

14. The Cu-Fe-SSZ-13 molecular sieve according to claim 11, wherein: The SiO2 / Al2O3 molar ratio of the Cu-Fe-SSZ-13 molecular sieve is ≥10; Preferably, the SiO2 / Al2O3 molar ratio of the Cu-Fe-SSZ-13 molecular sieve is ≥12; More preferably, the SiO2 / Al2O3 molar ratio of the Cu-Fe-SSZ-13 molecular sieve is ≥13; Further preferably, the SiO2 / Al2O3 molar ratio of the Cu-Fe-SSZ-13 molecular sieve is ≥13.

5.

15. The Cu-Fe-SSZ-13 molecular sieve according to claim 11, wherein: The relative crystallinity of the Cu-Fe-SSZ-13 molecular sieve is ≥85%; Preferably, the relative crystallinity of the Cu—Fe-SSZ-13 molecular sieve is ≥90%.

16. A catalyst, which is made from the Cu-Fe-SSZ-13 molecular sieve according to any one of claims 11 to 15.

17. The catalyst according to claim 16, wherein The preparation method of the catalyst comprises: mixing a Cu-Fe-SSZ-13 molecular sieve with an acid solution to obtain an acidic system, and performing acid exchange; performing hydrothermal ultra-stabilization treatment on the acid-exchanged molecular sieve to obtain the catalyst; Preferably, the mass ratio of the dry basis of the Cu-Fe-SSZ-13 molecular sieve to the acid solution is 1:5-20, and the pH value of the acidic system is 1.0-4.0; Preferably, the temperature of the acid exchange is 10-100°C, and the time of the acid exchange is 0.5h-5h; Preferably, the temperature of the hydrothermal ultra-stabilization treatment is 400-850°C, the time of the hydrothermal ultra-temperature treatment is 0.5-100h, and the hydrothermal ultra-stabilization treatment is carried out in a 5-100 vol% water vapor atmosphere; More preferably, the temperature of the hydrothermal ultrastabilization treatment is 500-800°C; More preferably, the hydrothermal superheat treatment time is 20-60h; More preferably, the hydrothermal ultrastabilization treatment is performed in a 7-50 vol% water vapor atmosphere.

18. Use of the catalyst according to any one of claims 16 to 17 in a DeNOx reaction.

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