WO2023216447A1 - 一种Cu-CHA与H-AEI的复合催化剂及其制备方法与应用 - Google Patents

一种Cu-CHA与H-AEI的复合催化剂及其制备方法与应用 Download PDF

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WO2023216447A1
WO2023216447A1 PCT/CN2022/112423 CN2022112423W WO2023216447A1 WO 2023216447 A1 WO2023216447 A1 WO 2023216447A1 CN 2022112423 W CN2022112423 W CN 2022112423W WO 2023216447 A1 WO2023216447 A1 WO 2023216447A1
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cha
zeolite
aei
composite catalyst
preparation
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PCT/CN2022/112423
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English (en)
French (fr)
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贺泓
单玉龙
陈俊林
石晓燕
余运波
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中国科学院生态环境研究中心
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • B01J29/80—Mixtures of different zeolites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • B01D53/9404—Removing only nitrogen compounds
    • B01D53/9409—Nitrogen oxides
    • B01D53/9413—Processes characterised by a specific catalyst
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • B01D53/9404—Removing only nitrogen compounds
    • B01D53/9409—Nitrogen oxides
    • B01D53/9413—Processes characterised by a specific catalyst
    • B01D53/9427—Processes characterised by a specific catalyst for removing nitrous oxide
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/20—Reductants
    • B01D2251/206—Ammonium compounds
    • B01D2251/2062—Ammonia
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2229/00—Aspects of molecular sieve catalysts not covered by B01J29/00
    • B01J2229/10—After treatment, characterised by the effect to be obtained
    • B01J2229/18—After treatment, characterised by the effect to be obtained to introduce other elements into or onto the molecular sieve itself
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • B01J29/70—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of types characterised by their specific structure not provided for in groups B01J29/08 - B01J29/65
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • B01J29/70—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of types characterised by their specific structure not provided for in groups B01J29/08 - B01J29/65
    • B01J29/72—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of types characterised by their specific structure not provided for in groups B01J29/08 - B01J29/65 containing iron group metals, noble metals or copper
    • B01J29/76—Iron group metals or copper
    • B01J29/763—CHA-type, e.g. Chabazite, LZ-218
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
    • Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

Definitions

  • the embodiments of the present application relate to the technical fields of industrial waste gas treatment and environmentally friendly catalytic materials, such as a composite catalyst of Cu-CHA and H-AEI, and in particular, to a composite catalyst of Cu-CHA and H-AEI and its preparation method and application.
  • Diesel vehicles especially heavy-duty diesel vehicles, have always been the main force in the long-distance freight market.
  • Ammonia selective catalytic reduction (NH 3 -SCR) is the most effective and widely used technology to purify diesel engine exhaust NO x . Its core is the development of efficient and stable NH 3 -SCR catalysts. As particulate matter (PM) and NO Because instantaneous high temperatures are generated during the DPF regeneration process, the exhaust gas containing high humidity will cause thermal shock to the SCR catalyst.
  • CN101668589A discloses a high-silicon Cu-CHA zeolite catalyst with a silica to alumina ratio of 15 to 256. It has relatively excellent NH 3 -SCR activity and hydrothermal stability, and is currently a mainstream commercial catalyst.
  • currently commercial catalysts are mostly based on high-silica molecular sieves with a silicon-to-aluminum ratio greater than 25.
  • high-silica molecular sieves have limited copper content and insufficient low-temperature activity.
  • aluminum-rich molecular sieves with lower silicon-to-aluminum ratios can accommodate more ion-exchange copper species and have more acidic sites, thus having better low-temperature NH 3 -SCR activity.
  • silicon-to-aluminum ratio is reduced and / Or the process of increasing the copper content will significantly reduce its hydrothermal stability.
  • CN113443637A discloses a zeolite molecular sieve with double acid centers and its preparation method and application.
  • the zeolite molecular sieve with double acid centers provided by this application includes a hydrogen-type zeolite molecular sieve and transition metal ions loaded in the pores of the hydrogen-type zeolite molecular sieve.
  • the loading amount of the transition metal ions is 0.01 to 10 wt%.
  • the zeolite molecular sieve with double acid centers provided by this application can break the kinetic limitations of the dehydration reaction process of amine compounds, making it easier to break C-O bonds than C-N bonds, and obtain a catalytic reaction with piperazine and its derivatives as the main products.
  • CN110523432A discloses a copper-containing molecular sieve Cu-CHA and its catalyst and its application in diesel vehicle exhaust treatment, belonging to the field of catalytic materials.
  • the copper-containing molecular sieve Cu-CHA is composed of a zeolite with a CHA framework structure including silicon, aluminum elements and 1.65-3.05wt% Cu.
  • the Cu-CHA molecular sieve also includes 0.5-1.5wt% boron.
  • the acid content of Cu-CHA molecular sieve is 0.25 ⁇ 0.98mmol/g.
  • the Cu-CHA molecular sieve of the present application has an acid density as high as 0.25 ⁇ 0.98mmol/g and a Cu content as low as 1.65 ⁇ 3.05wt%.
  • ammonia selective catalytic reduction catalysts all have certain defects, including low catalytic activity at low temperatures, poor hydrothermal stability, complex preparation methods, and high preparation costs. Therefore, it is crucial to develop and design a new composite catalyst of Cu-CHA and H-AEI and its preparation method.
  • the embodiments of this application provide a composite catalyst of Cu-CHA and H-AEI and its preparation method and application.
  • the composite catalyst of Cu-CHA and H-AEI described in this application has strong catalytic activity and strong hydrothermal stability. , The preparation method is simple and the preparation cost is low.
  • the composite catalyst of Cu-CHA and H-AEI is an efficient and stable NH 3 -SCR catalyst.
  • embodiments of the present application provide a composite catalyst of Cu-CHA and H-AEI, the composite catalyst includes Cu-CHA zeolite and H-AEI zeolite;
  • the composite catalyst has a NOx purification efficiency of ⁇ 85% under conditions of ⁇ 250°C;
  • the composite catalyst is subjected to hydrothermal aging treatment at 650 to 850°C for 10 to 120 hours.
  • the hydrothermally aged composite zeolite SCR catalyst has a NOx purification efficiency of ⁇ 70% at ⁇ 250°C.
  • NO _ _ _ Any one or a combination of at least two of O 3 ), dinitrogen tetroxide (N 2 O 4 ) and dinitrogen pentoxide (N 2 O 5 ).
  • Typical but non-limiting combinations include N 2 O and NO
  • the Cu-CHA zeolite described in this application is a zeolite with a CHA structure containing copper elements.
  • the Cu-CHA zeolite has strong NH 3 -SCR catalytic activity;
  • the H-AEI zeolite is a hydrogen-type zeolite with an AEI structure.
  • H-AEI zeolite basically has no NH 3 -SCR catalytic activity.
  • the composite catalyst mixed with Cu-CHA zeolite and H-AEI zeolite has stronger catalytic activity. Mixing H-AEI zeolite into Cu-CHA zeolite can ensure higher NH 3 -SCR catalytic activity while improving hydrothermal stability.
  • the composite catalyst of Cu-CHA and H-AEI described in this application has the advantages of excellent NH 3 -SCR catalytic activity, excellent hydrothermal stability, simple preparation method and low preparation cost.
  • the composite catalyst of Cu-CHA and H-AEI The catalyst is an efficient and stable NH 3 -SCR catalyst.
  • the reason why the composite catalyst of Cu-CHA and H-AEI described in this application has excellent hydrothermal stability is that there is a large amount of para-aluminum in H-AEI. After compounding with Cu-CHA, the Cu 2+ in Cu-CHA migrates to H In -AEI, Cu 2+ -2Al is formed instead of accumulating to form CuO Thermal stability is poor. Therefore, the hydrothermal stability of the composite catalyst of Cu-CHA and H-AEI in this application is better than that of ordinary SCR catalysts.
  • the mass ratio of the Cu-CHA zeolite to the H-AEI zeolite is (1-60):3, for example, it can be 1:3, 3:3, 6:3, 9:3, 12:3, 15 :3, 18:3, 21:3, 23:3, 25:3, 27:3, 30:3, 32:3, 35:3, 37:3, 40:3, 42:3, 45:3 , 47:3, 50:3, 52:3, 55:3, 57:3 or 60:3, but are not limited to the listed values. Other unlisted values within this range are also applicable, preferably (3 ⁇ 27):3; When the mass ratio of Cu-CHA zeolite to H-AEI zeolite is low, the NO x conversion efficiency will decrease.
  • the embodiments of the present application provide a method for preparing a composite catalyst as described in the first aspect.
  • the preparation method includes:
  • Cu-CHA zeolite and H-AEI zeolite are mixed to obtain the composite catalyst.
  • the preparation method of the composite catalyst described in the present application has the advantage of simple process.
  • the preparation method requires lower experimental conditions and has a wider application range.
  • the Cu-CHA zeolite is composed of dual six-membered rings stacked in the order AABBCCAA, and has a CHA cage structure with three-dimensional eight-membered ring channels.
  • the Cu-CHA zeolite contains a mass fraction of Cu of 2.0wt% to 10.0wt%, for example, it can be 2wt%, 2.5wt%, 3.0wt%, 3.5wt %,4.0wt%,4.5wt%,5.0wt%,5.5wt%,6.0wt%,6.5wt%,7.0wt%,7.5wt%,8.0wt%,8.5wt%,9.0wt%,9.5wt% or 10.0wt%, but is not limited to the listed values. Other unlisted values within this range are also applicable, preferably 3.5wt% to 7.5wt%.
  • the molar ratio of silica to alumina in the Cu-CHA zeolite is (6-25):1, for example, it can be 6:1, 8:1, 10:1, 12:1, 14:1 , 16:1, 18:1, 20:1, 22:1, 24:1 or 25:1, but are not limited to the listed values. Other unlisted values within this range are also applicable, preferably (6 ⁇ 20):1.
  • the molar ratio of silica to alumina in the H-AEI zeolite is (10-40):1, for example, it can be 10:1, 15:1, 20:1, 25:1, 30:1 , 35:1 or 40:1, but are not limited to the listed values, other unlisted values within this range are also applicable; when the molar ratio of silica to alumina in H-AEI zeolite is lower than 10:1 This will lead to a reduction in hydrothermal stability. This is because H-AEI has a low silicon-aluminum ratio and is prone to dealumination under hydrothermal aging conditions. When the molar ratio of silica to alumina in H-AEI zeolite is higher than 40:1, its acidic sites become less and cannot provide more ion exchange sites and acidic sites for Cu-CHA zeolite.
  • the mixing includes any one or a combination of at least two of liquid-liquid mixing, solid-liquid mixing or solid-liquid mixing.
  • Typical but non-limiting combinations include a combination of liquid-liquid mixing and solid-liquid mixing.
  • Solid-liquid mixing The combination of mixing and solid-solid mixing, or the combination of liquid-liquid mixing, solid-liquid mixing and solid-solid mixing.
  • the solid-solid mixing includes grinding method and/or physical mixing method.
  • the preparation method also includes the preparation of Cu-CHA zeolite:
  • the mixing temperature in step (1) is 20-50°C, for example, it can be 20°C, 25°C, 30°C, 35°C, 40°C, 45°C or 50°C, but is not limited to the listed values. , other unlisted values within this value range are also applicable.
  • the solid-liquid ratio of H-CHA and ammonium chloride solution in step (1) is 1:(5-30), for example, it can be 1:5, 1:10, 1:15, 1:20, 1 :25 or 1:30, but it is not limited to the listed values. Other unlisted values within this range of values are also applicable.
  • the unit of the solid-liquid ratio is g/mL.
  • the concentration of the ammonium chloride solution in step (1) is 0.1-0.2mol/L, for example, it can be 0.1mol/L, 0.11mol/L, 0.12mol/L, 0.13mol/L, 0.14mol/L , 0.15mol/L, 0.16mol/L, 0.17mol/L, 0.18mol/L, 0.19mol/L or 0.2mol/L, but not limited to the listed values, other unlisted values within this range are the same Be applicable.
  • the drying temperature in step (1) is 80-120°C, for example, it can be 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C or 120°C, but It is not limited to the listed values, and other unlisted values within the range of values are also applicable.
  • the mixing temperature in step (2) is 20-60°C, for example, it can be 20°C, 25°C, 30°C, 35°C, 40°C, 42°C, 45°C, 48°C, 50°C, 52°C , 55°C, 58°C or 60°C, but it is not limited to the listed values. Other unlisted values within this numerical range are also applicable.
  • the solid-liquid ratio of the intermediate described in step (2) to the copper salt solution is 1: (5-30), for example, it can be 1:5, 1:10, 1:15, 1:20, 1:25 Or 1:30, but it is not limited to the listed values. Other unlisted values within this range of values are also applicable.
  • the unit of the solid-liquid ratio is g/mL.
  • the copper salt in the copper salt solution includes any one or a combination of at least two of copper acetate, copper nitrate or copper sulfate.
  • Typical but non-limiting combinations include a combination of copper acetate and copper nitrate, nitric acid A combination of copper and copper sulfate, or a combination of copper acetate, copper nitrate and copper sulfate.
  • the concentration of the copper salt solution in step (2) is 0.01-0.3mol/L, for example, it can be 0.01mol/L, 0.1mol/L, 0.15mol/L, 0.2mol/L, 0.25mol/L or 0.3mol/L, but not limited to the listed values, other unlisted values within this range are also applicable.
  • the drying temperature in step (2) is 80-120°C, for example, it can be 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C or 120°C, but It is not limited to the listed values, and other unlisted values within the range of values are also applicable.
  • the calcination temperature in step (2) is 400°C to 600°C, and the time is 5 to 8 hours.
  • This application limits the calcination temperature to 400°C to 600°C.
  • it can be 400°C, 420°C, 450°C, 480°C, 500°C, 520°C, 550°C, 580°C or 600°C, but is not limited to the listed ones. value, other unlisted values within this value range are also applicable.
  • This application limits the calcination time to 5 to 8h. For example, it can be 5h, 5.2h, 5.5h, 5.8h, 6h, 6.2h, 6.5h, 6.8h, 7h, 7.2h, 7.5h, 7.8h or 8h. However, it is not limited to the listed values, and other unlisted values within the range of values are also applicable.
  • embodiments of the present application provide an application of a composite catalyst as described in the second aspect, where the composite catalyst is used for selective catalytic reduction of nitrogen oxides in diesel vehicle exhaust.
  • the composite catalyst is mixed with an auxiliary agent to obtain a slurry, and the slurry is coated on honeycomb ceramics, dried and roasted in sequence, and then used for selective catalytic reduction of nitrogen oxides in diesel vehicle exhaust.
  • the composite catalyst of Cu-CHA and H-AEI provided in the examples of this application has catalytic performance similar to that of Cu-CHA zeolite of the same quality, and the thermal stability of the composite catalyst is better than that of Cu-CHA zeolite of the same quality. ;
  • Mixing H-AEI zeolite with poor catalytic activity into Cu-CHA zeolite with strong catalytic activity can improve NH 3 -SCR activity and enhance hydrothermal stability;
  • the composite catalyst of Cu-CHA and H-AEI provided in the embodiments of the present application has a purification efficiency of NO x of ⁇ 85% under the conditions of ⁇ 250°C; the composite catalyst is heat-treated under the conditions of 650 to 850°C. 10 ⁇ 120h, the purification efficiency of NOx of the composite zeolite SCR catalyst after hydrothermal treatment is ⁇ 70% at ⁇ 250°C;
  • the composite catalyst of Cu-CHA and H-AEI provided in the embodiments of this application has the advantages of strong catalytic activity, strong hydrothermal stability, simple preparation method and low preparation cost.
  • the Cu-CHA and H- AEI's composite catalyst is an efficient and stable NH 3 -SCR catalyst.
  • Figure 1 is the conversion efficiency curve of NOx at different temperatures for the composite catalyst of Cu-CHA and H-AEI in Example 1 and the composite catalyst of Cu-CHA and H-AEI after hydrothermal treatment.
  • Figure 2 is a conversion efficiency curve of NOx at different temperatures for the composite catalyst of Cu-CHA and H-AEI in Example 2 and the composite catalyst of Cu-CHA and H-AEI after hydrothermal treatment.
  • Figure 3 is a conversion efficiency curve of NOx at different temperatures for the Cu-CHA zeolite in Comparative Example 1 and the Cu-CHA zeolite after hydrothermal treatment.
  • Figure 4 is a conversion efficiency curve of NO x at different temperatures for the H-AEI zeolite in Comparative Example 2 and the H-AEI zeolite after hydrothermal treatment.
  • This embodiment provides a composite catalyst of Cu-CHA and H-AEI.
  • the composite catalyst includes Cu-CHA zeolite with a mass ratio of 27:3 and SSZ-39 hydrogen zeolite with a structural type of AEI (H-AEI zeolite).
  • the preparation method of the composite zeolite SCR catalyst includes:
  • the composite catalyst is obtained by grinding and mixing Cu-CHA zeolite and H-AEI zeolite;
  • the mass fraction of Cu in the Cu-CHA zeolite is 4.2%, and the molar ratio of silica to alumina is 9:1; in the H-AEI zeolite, the molar ratio of silica to alumina is 9:1.
  • the molar ratio of alumina is 20:1.
  • the preparation method of the Cu-CHA zeolite includes the following steps:
  • This embodiment provides a composite catalyst of Cu-CHA and H-AEI.
  • the composite catalyst includes Cu-CHA zeolite with a mass ratio of 60:3 and SSZ-39 hydrogen zeolite with a structural type of AEI (H-AEI zeolite).
  • the preparation method of the composite zeolite SCR catalyst includes:
  • the composite catalyst is obtained by grinding and mixing Cu-CHA zeolite and H-AEI zeolite;
  • the mass fraction of Cu in the Cu-CHA zeolite is 2.4%, and the molar ratio of silica to alumina is 20:1; the silica and alumina in the H-AEI zeolite are The molar ratio of alumina is 25:1.
  • the preparation method of the Cu-CHA zeolite includes the following steps:
  • This embodiment provides a composite catalyst of Cu-CHA and H-AEI.
  • the composite catalyst includes Cu-CHA zeolite with a mass ratio of 7:3 and SSZ-39 hydrogen zeolite with a structural type of AEI (H-AEI zeolite).
  • the preparation method of the composite zeolite SCR catalyst includes:
  • the composite catalyst is obtained by grinding and mixing Cu-CHA zeolite and H-AEI zeolite;
  • the mass fraction of Cu in the Cu-CHA zeolite is 5.6%, and the molar ratio of silica to alumina is 12:1; in the H-AEI zeolite, the molar ratio of silica to alumina is 12:1.
  • the molar ratio of alumina is 40:1.
  • the preparation method of the Cu-CHA zeolite includes the following steps:
  • This embodiment provides a composite catalyst of Cu-CHA and H-AEI.
  • the composite catalyst includes Cu-CHA zeolite with a mass ratio of 5:3 and SSZ-39 hydrogen zeolite with a structural type of AEI (H-AEI zeolite).
  • the preparation method of the composite zeolite SCR catalyst includes:
  • the composite catalyst is obtained by grinding and mixing Cu-CHA zeolite and H-AEI zeolite;
  • the mass fraction of Cu in the Cu-CHA zeolite is 2%, and the molar ratio of silica to alumina is 16:1; the silica and alumina in the H-AEI zeolite are The molar ratio of aluminum oxide is 10:1.
  • the preparation method of the Cu-CHA zeolite includes the following steps:
  • This embodiment provides a composite catalyst of Cu-CHA and H-AEI.
  • the composite catalyst includes Cu-CHA zeolite with a mass ratio of 1:3 and SSZ-39 hydrogen zeolite with a structural type of AEI (H-AEI zeolite).
  • the preparation method of the composite zeolite SCR catalyst includes:
  • the composite catalyst is obtained by grinding and mixing Cu-CHA zeolite and H-AEI zeolite;
  • the mass fraction of Cu in the Cu-CHA zeolite is 10%, and the molar ratio of silica to alumina is 6:1; in the H-AEI zeolite, the molar ratio of silica to The molar ratio of alumina is 17:1.
  • the preparation method of the Cu-CHA zeolite includes the following steps:
  • This embodiment provides a composite catalyst of Cu-CHA and H-AEI, which is the same as Example 1 except that the mass ratio of Cu-CHA zeolite to H-AEI zeolite is 0.5:3.
  • This embodiment provides a composite catalyst of Cu-CHA and H-AEI, which is the same as Example 1 except that the mass ratio of Cu-CHA zeolite to H-AEI zeolite is 65:3.
  • This example provides a composite catalyst of Cu-CHA and H-AEI, which is the same as Example 1 except that the molar ratio of silica to alumina in the Cu-CHA zeolite is 4:1.
  • This example provides a composite catalyst of Cu-CHA and H-AEI, which is the same as Example 1 except that the molar ratio of silica to alumina in the Cu-CHA zeolite is 30:1.
  • This example provides a composite catalyst of Cu-CHA and H-AEI, which is the same as Example 1 except that the molar ratio of silica to alumina in the H-AEI zeolite is 5:1.
  • This example provides a composite catalyst of Cu-CHA and H-AEI, which is the same as Example 1 except that the molar ratio of silica to alumina in the H-AEI zeolite is 50:1.
  • This comparative example provides a Cu-CHA zeolite, which is obtained by the preparation method of Cu-CHA zeolite in Example 2.
  • This comparative example provides an H-AEI zeolite, which is the same as the H-AEI zeolite in Example 1.
  • the composite catalysts described in Examples 1 to 11, the Cu-CHA zeolite described in Comparative Example 1 and the H-AEI zeolite described in Comparative Example 2 are heat treated with equal masses.
  • the heat treatment method includes: weighing an appropriate amount of the composite catalyst and Cu-CHA zeolite and H-AEI zeolite were put into quartz tubes and placed in a temperature-controlled resistance furnace, and air containing 10% water was introduced as the carrier gas, and treated at 800°C for 16 hours to obtain the hydrothermally treated composite catalyst and the hydrothermally treated Cu- CHA zeolite and hydrothermally treated H-AEI zeolite.
  • the composite catalyst described in Examples 1 to 11, the Cu-CHA zeolite described in Comparative Example 1 and the H-AEI zeolite described in Comparative Example 2 the composite catalyst after heat treatment, the Cu-CHA zeolite after heat treatment and the heat treatment H-AEI zeolite is used in NH 3 -SCR catalytic reaction:
  • the test gas is introduced and tested.
  • the Fourier transform infrared spectrometer detects the components in the exhaust gas and calculates the NO 3 and 5% O 2 , the balance gas is N 2 , measure the curve and data of NO x conversion rate changing with reaction temperature;
  • the NO x conversion efficiency of the NH 3 -SCR catalytic reaction using the composite catalyst of Cu-CHA and H-AEI obtained in Examples 1 to 5 is relatively high, and it still has high NO x conversion after hydrothermal treatment at 800°C. Efficiency; the composite catalyst of Cu-CHA and H-AEI described in this application has the advantages of strong catalytic activity, strong hydrothermal stability, simple preparation method and low preparation cost.
  • the composite catalyst of Cu-CHA and H-AEI The catalyst is an efficient and stable NH 3 -SCR catalyst.
  • Example 2 From the comparison between Example 1 and Examples 6 and 7, it can be seen that the mass ratio of Cu-CHA zeolite and H-AEI zeolite described in this application will affect the NO x conversion efficiency of the NH 3 -SCR catalytic reaction; when Cu- When the mass ratio of CHA zeolite to H-AEI zeolite is too low, the NO When it is high, it will cause the NOx conversion efficiency to increase and the hydrothermal stability to decrease. This is because there is more copper in the catalyst. After hydrothermal aging, CuOx agglomeration is easily formed, causing the skeleton to collapse.
  • Example 1 It can be seen from the comparison between Example 1 and Examples 8 and 9 that the molar ratio of silica to alumina in the Cu-CHA zeolite described in this application will affect the NO x conversion efficiency of the NH 3 -SCR catalytic reaction; when When the molar ratio of silica to alumina in Cu-CHA zeolite is low, the hydrothermal stability will be reduced. This is because the silicon-aluminum ratio is low and the Cu-CHA system contains more aluminum, so the hydrothermal stability will be reduced.
  • Example 2 From the comparison between Example 2 and Comparative Example 1 and between Example 1 and Comparative Example 2, it can be seen that the NH 3 -SCR activity of the Cu-CHA zeolite described in this application is relatively strong, and the NH 3 -SCR activity of the H-AEI zeolite is relatively strong. SCR activity is poor, and the composite catalyst mixed with Cu-CHA zeolite and H-AEI zeolite has strong catalytic activity. Mixing H-AEI zeolite into Cu-CHA zeolite can ensure high NH 3 -SCR catalytic activity while enhancing water Thermal stability.
  • the composite catalyst of Cu-CHA and H-AEI provided by this application has catalytic performance similar to that of Cu-CHA zeolite of the same quality, and the thermal stability of the composite catalyst is better than that of Cu-CHA zeolite of the same quality.
  • the NOx purification efficiency of the composite catalyst is ⁇ 85% under the condition of ⁇ 250°C; the composite catalyst is hydrothermally treated at 650-850°C for 10-120 hours, and the hydrothermally treated composite zeolite SCR catalyst is treated at ⁇ 250°C.
  • the purification efficiency of NO -The composite catalyst of CHA and H-AEI is an efficient and stable NH 3 -SCR catalyst.

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Abstract

一种Cu-CHA与H-AEI的复合催化剂及其制备方法与应用，复合催化剂包括Cu-CHA沸石与H-AEI沸石；复合催化剂在≥250℃的条件下对NO x的净化效率为≥85％；复合催化剂在650～850℃的条件下水热老化处理10～120h，水热老化处理后的复合沸石SCR催化剂在≥250℃下对NO x的净化效率≥70％。该Cu-CHA与H-AEI的复合催化剂具有催化活性较强、水热稳定性较强、制备方法简单及制备成本低的优点，Cu-CHA与H-AEI的复合催化剂是一种高效稳定的NH 3-SCR催化剂。

Description

一种Cu-CHA与H-AEI的复合催化剂及其制备方法与应用 技术领域
本申请实施例涉及工业废气处理和环保催化材料技术领域，例如一种Cu-CHA与H-AEI的复合催化剂，尤其涉及一种Cu-CHA与H-AEI的复合催化剂及其制备方法与应用。
背景技术
一直以来，柴油车尤其是重型柴油车是长途货运市场的主力。柴油车尤其是柴油货车高频、长距离运行导致其主要污染物氮氧化物(NO x)排放量大，已成为大气灰霾(PM2.5)、臭氧(O 3)污染形成的重要原因。氨气选择性催化还原(NH 3-SCR)是净化柴油机尾气NO x的最有效且应用最广泛的技术，其核心是高效稳定的NH 3-SCR催化剂的研发。由于颗粒物(PM)和NO x需要协同控制，需要颗粒补集器(DPF)与SCR耦合技术，因此SCR催化剂除具备较高的NH 3-SCR活性外，还需具备优异的水热稳定性，因为DPF再生过程中会产生瞬时高温，包含高湿的尾气会对SCR催化剂造成热冲击。
CN101668589A公开了一种二氧化硅与氧化铝比率为15～256的高硅Cu-CHA沸石催化剂，具有较为优异的NH 3-SCR活性和水热稳定性，为目前主流的商用催化剂。为了保证Cu-CHA沸石分子筛的水热稳定性，目前商用的催化剂多是基于硅铝比大于25的高硅分子筛。然而，高硅分子筛由于缺少酸性位，赋铜量有限，其低温活性不足。理论上，具有较低硅铝比的富铝分子筛由于可容纳更多的离子交换铜物种和具有更多的酸性位，从而具有更优异的低温NH 3-SCR活性，但是在降低硅铝比和/或提高赋铜量的过程会显著降低其水热稳定性。
CN113443637A公开了一种双酸中心的沸石分子筛及其制备方法和应用。该申请提供的双酸中心的沸石分子筛，包括氢型沸石分子筛和负载于所述氢型沸石分子筛孔道内的过渡金属离子，所述过渡金属离子的负载量为0.01～10wt％。本申请提供的双酸中心的沸石分子筛能够打破胺类化合物脱水反应过程的动力学限制，使得C-O相较于C-N键更容易断裂，得到以哌嗪及其衍生物为主要产物的催化反应。
CN110523432A公开了一种含铜分子筛Cu-CHA及其催化剂和在柴油车尾气处理中的应用，属于催化材料领域。该含铜分子筛Cu-CHA，其组成包含硅、铝元素和1.65～3.05wt％的Cu的具有CHA骨架结构的沸石，所述Cu-CHA分子筛中还包括0.5～1.5wt％的硼，所述Cu-CHA分子筛酸量为0.25～0.98mmol/g。本申请的Cu-CHA分子筛的酸密度高达0.25～0.98mmol/g和Cu含量低至1.65～3.05wt％。
目前公开的氨气选择性催化还原催化剂都有一定的缺陷，存在着催化剂在低温下的催化活性较低、水热稳定较差，制备方法复杂及制备成本高的问题。因此，开发设计一种新型的Cu-CHA与H-AEI的复合催化剂及其制备方法至关重要。
发明内容
以下是对本文详细描述的主题的概述。本概述并非是为了限制权利要求的保护范围。
本申请实施例提供一种Cu-CHA与H-AEI的复合催化剂及其制备方法与应用，本申请所述Cu-CHA与H-AEI的复合催化剂具有催化活性较强、水热稳定性较强、制备方法简单及制备成本低的优点，所述Cu-CHA与H-AEI的复合催化剂是一种高效稳定的NH 3-SCR催化剂。
第一方面，本申请实施例提供了一种Cu-CHA与H-AEI的复合催化剂，所述复合催化剂包括Cu-CHA沸石与H-AEI沸石；
所述复合催化剂在≥250℃的条件下对NO x的净化效率≥85％；
所述复合催化剂在650～850℃的条件下水热老化处理10～120h，水热老化处理的复合沸石SCR催化剂在≥250℃下对NO x的净化效率≥70％。
本申请所述NO x是指氮氧化物，所述氮氧化物包括一氧化二氮(N 2O)、一氧化氮(NO)、二氧化氮(NO 2)、三氧化二氮(N 2O 3)、四氧化二氮(N 2O 4)和五氧化二氮(N 2O 5)中的任意一种或至少两种的组合，典型但非限制性的组合包括N 2O与NO的组合，NO与NO 2的组合，NO 2与N 2O 3的组合，N 2O 3与N 2O 4的组合，N 2O 4与N 2O 5的组合，N 2O、NO与NO 2的组合，或NO 2、N 2O 3、N 2O 4与N 2O 5的组合
本申请所述Cu-CHA沸石为含有铜元素的具有CHA结构的沸石，所述 Cu-CHA沸石的NH 3-SCR催化活性较强；所述H-AEI沸石为具有AEI结构的氢型沸石，H-AEI沸石基本不具备NH 3-SCR催化活性，Cu-CHA沸石与H-AEI沸石混合的复合催化剂的催化活性较强，在Cu-CHA沸石中混入H-AEI沸石能够在保证较高NH 3-SCR催化活性的同时提高水热稳定性。
本申请所述Cu-CHA与H-AEI的复合催化剂具有优良NH 3-SCR催化活性、优异水热稳定性、制备方法简单及制备成本低的优点，所述Cu-CHA与H-AEI的复合催化剂是一种高效稳定的NH 3-SCR催化剂。
本申请所述Cu-CHA与H-AEI的复合催化剂具备优异水热稳定性的原因在于H-AEI中存在大量对铝，与Cu-CHA复合后，Cu-CHA中的Cu 2+迁移到H-AEI中，形成Cu 2+-2Al，而不是积聚形成CuO x颗粒，有利于维持分子筛骨架的稳定性；而在普通SCR催化剂中，由于骨架脱铝、铜物种发生团聚等原因，导致其水热稳定性较差。故在本申请中的Cu-CHA与H-AEI的复合催化剂的水热稳定性要优于普通SCR催化剂。
优选地，所述Cu-CHA沸石与H-AEI沸石的质量比为(1～60):3，例如可以是1:3、3:3、6:3、9:3、12:3、15:3、18:3、21:3、23:3、25:3、27:3、30:3、32:3、35:3、37:3、40:3、42:3、45:3、47:3、50:3、52:3、55:3、57:3或60:3，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用，优选为(3～27):3；当Cu-CHA沸石与H-AEI沸石的质量比偏低时，会导致NO x转化效率降低，这是由于存在较多的H-AEI，催化剂中活性位点含量较少，不能起到较好的催化效果；当Cu-CHA沸石与H-AEI沸石的质量比偏高时，虽然新鲜态催化剂的NO x转化效率较高，但水热稳定性降低，老化后其NO x转化效率变低，这是由于存在较多的Cu-CHA，复合催化剂体系近似于纯Cu-CHA，在水热老化之后，骨架容易脱铝，且铜易于团聚形成CuO x颗粒导致活性降低，故其水热稳定性会下降。
第二方面，本申请实施例提供了一种如第一方面所述复合催化剂的制备方法，所述制备方法包括：
混合Cu-CHA沸石与H-AEI沸石，得到所述复合催化剂。
本申请所述复合催化剂的制备方法具有工艺简单的优点，所述制备方法的实验条件要求较低且适用范围较广。
优选地，所述Cu-CHA沸石是由双六元环以AABBCCAA顺序堆积而成， 具有三维八元环孔道的CHA笼结构。
优选地，以Cu-CHA沸石的质量为基准，所述Cu-CHA沸石中含有质量分数为2.0wt％～10.0wt％的Cu，例如可以是2wt％、2.5wt％、3.0wt％、3.5wt％、4.0wt％、4.5wt％、5.0wt％、5.5wt％、6.0wt％、6.5wt％、7.0wt％、7.5wt％、8.0wt％、8.5wt％、9.0wt％、9.5wt％或10.0wt％，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用，优选为3.5wt％～7.5wt％。
优选地，所述Cu-CHA沸石中二氧化硅与氧化铝的摩尔比为(6～25):1，例如可以是6:1、8:1、10:1、12:1、14:1、16:1、18:1、20:1、22:1、24:1或25:1，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用，优选为(6～20):1。
本申请所述Cu-CHA沸石中二氧化硅与氧化铝的摩尔比偏低时，虽然NO x转化效率较高，但水热稳定性会降低，这是由于硅铝比偏低，体系中含量较多的铝，所以在水热老化时极易发生脱铝，使骨架结构被破坏，故其水热稳定性下降；当Cu-CHA沸石中二氧化硅与氧化铝的摩尔比偏高时，会导致NO x转化效率降低，这是由于此时催化剂中存在的活性位点较少，催化活性下降。
优选地，所述H-AEI沸石中二氧化硅与氧化铝的摩尔比为(10～40):1，例如可以是10:1、15:1、20:1、25:1、30:1、35:1或40:1，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用；当H-AEI沸石中二氧化硅与氧化铝的摩尔比低于10:1时，会导致水热稳定性降低，这是由于H-AEI硅铝比较低，容易在水热老化条件下发生脱铝。当H-AEI沸石中二氧化硅与氧化铝的摩尔比高于40:1时，其酸性位变少，无法为Cu-CHA沸石提供更多的离子交换位和酸性位。
优选地，所述混合包括液液混合、固液混合或固固混合中的任意一种或至少两种的组合，典型但非限制性的组合包括液液混合与固液混合的组合，固液混合与固固混合的组合，或液液混合、固液混合与固固混合的组合。
优选地，所述固固混合包括研磨法和/或物理混合法。
优选地，所述制备方法还包括Cu-CHA沸石的制备：
(1)混合H-CHA与氯化铵溶液，过滤，烘干，得到中间体；
(2)混合中间体与铜盐溶液，过滤，烘干后进行煅烧，得到所述Cu-CHA沸石。
优选地，步骤(1)所述混合的温度为20～50℃，例如可以是20℃、25℃、30℃、35℃、40℃、45℃或50℃，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用。
优选地，步骤(1)所述H-CHA与氯化铵溶液的固液比为1:(5～30)，例如可以是1:5、1:10、1:15、1:20、1:25或1:30，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用，所述固液比的单位为g/mL。
优选地，步骤(1)所述氯化铵溶液的浓度为0.1～0.2mol/L，例如可以是0.1mol/L、0.11mol/L、0.12mol/L、0.13mol/L、0.14mol/L、0.15mol/L、0.16mol/L、0.17mol/L、0.18mol/L、0.19mol/L或0.2mol/L，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用。
优选地，步骤(1)所述烘干的温度为80～120℃，例如可以是80℃、85℃、90℃、95℃、100℃、105℃、110℃、115℃或120℃，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用。
优选地，步骤(2)所述混合的温度为20～60℃，例如可以是20℃、25℃、30℃、35℃、40℃、42℃、45℃、48℃、50℃、52℃、55℃、58℃或60℃，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用。
优选地，步骤(2)所述中间体与铜盐溶液的固液比为1:(5～30)，例如可以是1:5、1:10、1:15、1:20、1:25或1:30，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用，所述固液比的单位为g/mL。
优选地，所述铜盐溶液中的铜盐包括乙酸铜、硝酸铜或硫酸铜中的任意一种或至少两种的组合，典型但非限制性的组合包括乙酸铜与硝酸铜的组合，硝酸铜与硫酸铜的组合，或乙酸铜、硝酸铜与硫酸铜的组合。
优选地，步骤(2)所述铜盐溶液的浓度为0.01～0.3mol/L，例如可以是0.01mol/L、0.1mol/L、0.15mol/L、0.2mol/L、0.25mol/L或0.3mol/L，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用。
优选地，步骤(2)所述烘干的温度为80～120℃，例如可以是80℃、85℃、90℃、95℃、100℃、105℃、110℃、115℃或120℃，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用。
优选地，步骤(2)所述煅烧的温度为400℃～600℃，时间为5～8h。
本申请限定了煅烧的温度为400℃～600℃，例如可以是400℃、420℃、450℃、 480℃、500℃、520℃、550℃、580℃或600℃，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用。
本申请限定了煅烧的时间为5～8h，例如可以是5h、5.2h、5.5h、5.8h、6h、6.2h、6.5h、6.8h、7h、7.2h、7.5h、7.8h或8h，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用。
第三方面，本申请实施例提供了一种如第二方面所述复合催化剂的应用，所述复合催化剂用于选择性催化还原柴油车尾气中氮氧化物。
优选地，所述复合催化剂与助剂混合后得到浆液，将浆液涂覆于蜂窝陶瓷，依次经干燥与焙烧后，用于选择性催化还原柴油车尾气中氮氧化物。
相对于相关技术，本申请实施例具有以下有益效果：
(1)本申请实施例提供的Cu-CHA与H-AEI的复合催化剂具有与同样质量的Cu-CHA沸石相近的催化性能，所述复合催化剂的热稳定性优于同样质量的Cu-CHA沸石；在催化活性较强的Cu-CHA沸石中混入催化活性较差的H-AEI沸石能够在提升NH 3-SCR活性的同时增强水热稳定性；
(2)本申请实施例提供的Cu-CHA与H-AEI的复合催化剂在≥250℃的条件下对NO x的净化效率为≥85％；所述复合催化剂在650～850℃的条件下热处理10～120h，水热处理后的复合沸石SCR催化剂在≥250℃下对NO x的净化效率≥70％；
(3)本申请实施例提供的Cu-CHA与H-AEI的复合催化剂具有催化活性较强、水热稳定性较强、制备方法简单及制备成本低的优点，所述Cu-CHA与H-AEI的复合催化剂是一种高效稳定的NH 3-SCR催化剂。
在阅读并理解了附图和详细描述后，可以明白其他方面。
附图说明
附图用来提供对本文技术方案的进一步理解，并且构成说明书的一部分，与本申请的实施例一起用于解释本文的技术方案，并不构成对本文技术方案的限制。
图1是实施例1中Cu-CHA与H-AEI的复合催化剂及水热处理后的Cu-CHA与H-AEI的复合催化剂在不同温度下对NO x的转化效率曲线。
图2是实施例2中Cu-CHA与H-AEI的复合催化剂及水热处理后的Cu-CHA 与H-AEI的复合催化剂在不同温度下对NO x的转化效率曲线。
图3是对比例1中Cu-CHA沸石及水热处理后的Cu-CHA沸石在不同温度下对NO x的转化效率曲线。
图4是对比例2中H-AEI沸石及水热处理后的H-AEI沸石在不同温度下对NO x的转化效率曲线。
具体实施方式
下面通过具体实施方式来进一步说明本申请的技术方案。本领域技术人员应该明了，所述实施例仅仅是帮助理解本申请，不应视为对本申请的具体限制。
实施例1
本实施例提供了一种Cu-CHA与H-AEI的复合催化剂，所述复合催化剂包括质量比为27:3的Cu-CHA沸石与结构类型为AEI的SSZ-39氢型沸石(H-AEI沸石)。
所述复合沸石SCR催化剂的制备方法包括：
通过研磨混合Cu-CHA沸石与H-AEI沸石，得到所述复合催化剂；
以Cu-CHA沸石的质量为基准，所述Cu-CHA沸石中Cu的质量分数为4.2％，二氧化硅与氧化铝的摩尔比为9:1；所述H-AEI沸石中二氧化硅与氧化铝的摩尔比为20:1。
所述Cu-CHA沸石的制备方法包括如下步骤：
(1)在30℃下以500rpm的速度搅拌混合结构类型为CHA的SSZ-13氢型沸石与浓度为0.2mol/L的氯化铵溶液，SSZ-13氢型沸石与氯化铵溶液的固液比为1:20，所述固液比的单位为g/mL，以110℃进行烘干，得到中间体；
(2)在40℃下以500rpm的速度搅拌混合中间体与浓度为0.2mol/L的硝酸铜溶液，中间体与硝酸铜溶液的固液比为1:10，所述固液比的单位为g/mL，以110℃进行烘干后在450℃煅烧7h，得到所述Cu-CHA沸石。
实施例2
本实施例提供了一种Cu-CHA与H-AEI的复合催化剂，所述复合催化剂包括质量比为60:3的Cu-CHA沸石与结构类型为AEI的SSZ-39氢型沸石(H-AEI沸石)。
所述复合沸石SCR催化剂的制备方法包括：
通过研磨混合Cu-CHA沸石与H-AEI沸石，得到所述复合催化剂；
以Cu-CHA沸石的质量为基准，所述Cu-CHA沸石中Cu的质量分数为2.4％，二氧化硅与氧化铝的摩尔比为20:1；所述H-AEI沸石中二氧化硅与氧化铝的摩尔比为25:1。
所述Cu-CHA沸石的制备方法包括如下步骤：
(1)在50℃下以600rpm的速度搅拌混合结构类型为CHA的SSZ-13氢型沸石与浓度为0.18mol/L的氯化铵溶液，SSZ-13氢型沸石与氯化铵溶液的固液比为1:25，所述固液比的单位为g/mL，以100℃进行烘干，得到中间体；
(2)在55℃下以500rpm的速度搅拌混合中间体与浓度为0.25mol/L的硝酸铜溶液，中间体与硝酸铜溶液的固液比为1:20，所述固液比的单位为g/mL，以100℃进行烘干后在500℃煅烧5.5h，得到所述Cu-CHA沸石。
实施例3
本实施例提供了一种Cu-CHA与H-AEI的复合催化剂，所述复合催化剂包括质量比为7:3的Cu-CHA沸石与结构类型为AEI的SSZ-39氢型沸石(H-AEI沸石)。
所述复合沸石SCR催化剂的制备方法包括：
通过研磨混合Cu-CHA沸石与H-AEI沸石，得到所述复合催化剂；
以Cu-CHA沸石的质量为基准，所述Cu-CHA沸石中Cu的质量分数为5.6％，二氧化硅与氧化铝的摩尔比为12:1；所述H-AEI沸石中二氧化硅与氧化铝的摩尔比为40:1。
所述Cu-CHA沸石的制备方法包括如下步骤：
(1)在40℃下以400rpm的速度搅拌混合结构类型为CHA的SSZ-13氢型沸石与浓度为0.13mol/L的氯化铵溶液，SSZ-13氢型沸石与氯化铵溶液的固液比为1:30，所述固液比的单位为g/mL，以90℃进行烘干，得到中间体；
(2)在45℃下以600rpm的速度搅拌混合中间体与浓度为0.01mol/L的硝酸铜溶液，中间体与硝酸铜溶液的固液比为1:100，所述固液比的单位为g/mL，以120℃进行烘干后在400℃煅烧10h，得到所述Cu-CHA沸石。
实施例4
本实施例提供了一种Cu-CHA与H-AEI的复合催化剂，所述复合催化剂包括质量比为5:3的Cu-CHA沸石与结构类型为AEI的SSZ-39氢型沸石(H-AEI 沸石)。
所述复合沸石SCR催化剂的制备方法包括：
通过研磨混合Cu-CHA沸石与H-AEI沸石，得到所述复合催化剂；
以Cu-CHA沸石的质量为基准，所述Cu-CHA沸石中Cu的质量分数为2％，二氧化硅与氧化铝的摩尔比为16:1；所述H-AEI沸石中二氧化硅与氧化铝的摩尔比为10:1。
所述Cu-CHA沸石的制备方法包括如下步骤：
(1)在20℃下以700rpm的速度搅拌混合结构类型为CHA的SSZ-13氢型沸石与浓度为0.1mol/L的氯化铵溶液，SSZ-13氢型沸石与氯化铵溶液的固液比为1:5，所述固液比的单位为g/mL，以80℃进行烘干，得到中间体；
(2)在60℃下以300rpm的速度搅拌混合中间体与浓度为0.3mol/L的硝酸铜溶液，中间体与硝酸铜溶液的固液比为1:5，所述固液比的单位为g/mL，以90℃进行烘干后在600℃煅烧5h，得到所述Cu-CHA沸石。
实施例5
本实施例提供了一种Cu-CHA与H-AEI的复合催化剂，所述复合催化剂包括质量比为1:3的Cu-CHA沸石与结构类型为AEI的SSZ-39氢型沸石(H-AEI沸石)。
所述复合沸石SCR催化剂的制备方法包括：
通过研磨混合Cu-CHA沸石与H-AEI沸石，得到所述复合催化剂；
以Cu-CHA沸石的质量为基准，所述Cu-CHA沸石中Cu的质量分数为10％，二氧化硅与氧化铝的摩尔比为6:1；所述H-AEI沸石中二氧化硅与氧化铝的摩尔比为17:1。
所述Cu-CHA沸石的制备方法包括如下步骤：
(1)在40℃下以300rpm的速度搅拌混合结构类型为CHA的SSZ-13氢型沸石与浓度为.0.15mol/L的氯化铵溶液，SSZ-13氢型沸石与氯化铵溶液的固液比为1:15，所述固液比的单位为g/mL，以120℃进行烘干，得到中间体；
(2)在20℃下以600rpm的速度搅拌混合中间体与浓度为0.1mol/L的硝酸铜溶液，中间体与硫酸铜溶液的固液比为1:30，所述固液比的单位为g/mL，以80℃进行烘干后在400℃煅烧8h，得到所述Cu-CHA沸石。
实施例6
本实施例提供了一种Cu-CHA与H-AEI的复合催化剂，除Cu-CHA沸石与H-AEI沸石的质量比为0.5:3外，其余均与实施例1相同。
实施例7
本实施例提供了一种Cu-CHA与H-AEI的复合催化剂，除Cu-CHA沸石与H-AEI沸石的质量比为65:3外，其余均与实施例1相同。
实施例8
本实施例提供了一种Cu-CHA与H-AEI的复合催化剂，除Cu-CHA沸石中二氧化硅与氧化铝的摩尔比为4:1外，其余均与实施例1相同。
实施例9
本实施例提供了一种Cu-CHA与H-AEI的复合催化剂，除Cu-CHA沸石中二氧化硅与氧化铝的摩尔比为30:1外，其余均与实施例1相同。
实施例10
本实施例提供了一种Cu-CHA与H-AEI的复合催化剂，除H-AEI沸石中二氧化硅与氧化铝的摩尔比为5:1外，其余均与实施例1相同。
实施例11
本实施例提供了一种Cu-CHA与H-AEI的复合催化剂，除H-AEI沸石中二氧化硅与氧化铝的摩尔比为50:1外，其余均与实施例1相同。
对比例1
本对比例提供了一种Cu-CHA沸石，所述Cu-CHA沸石由实施例2中Cu-CHA沸石的制备方法得到。
对比例2
本对比例提供了一种H-AEI沸石，所述H-AEI沸石与实施例1中H-AEI沸石相同。
以等质量实施例1～11所述的复合催化剂、对比例1所述Cu-CHA沸石与对比例2所述H-AEI沸石进行热处理，热处理方法包括：称取适量复合催化剂、Cu-CHA沸石和H-AEI沸石分别装入石英管置于可控温电阻炉中，通入含水10％、空气作为载气，在800℃处理16h，得到水热处理后的复合催化剂、水热处理后的Cu-CHA沸石与水热处理后的H-AEI沸石。
以等质量实施例1～11所述复合催化剂、对比例1所述Cu-CHA沸石与对比 例2所述H-AEI沸石、热处理后的复合催化剂、热处理后的Cu-CHA沸石与热处理后的H-AEI沸石用于NH 3-SCR催化反应：
通入试验气体并进行测试，由傅里叶变换红外光谱仪检测尾气中的成分组成，并计算NO x转化效率；其中，测试空速200,000h -1，试验气体组成为500ppm的NO、500ppm的NH 3和5％的O 2，平衡气为N 2，测量NO x转化率随反应温度变化的曲线及数据；
不同反应温度下复合催化剂、Cu-CHA沸石与H-AEI沸石的NH 3-SCR催化反应的NO x转化效率如表1所示；
不同反应温度下水热老化处理后的复合催化剂、热处理后的Cu-CHA沸石与热处理后的H-AEI沸石的NH 3-SCR催化反应的NO x转化效率如表2所示；
实施例1中Cu-CHA与H-AEI的复合催化剂及热处理后的Cu-CHA与H-AEI的复合催化剂在不同温度下对NOx的转化效率曲线如图1所示；
实施例2中Cu-CHA与H-AEI的复合催化剂及热处理后的Cu-CHA与H-AEI的复合催化剂在不同温度下对NO x的转化效率曲线如图2所示；
对比例1中Cu-CHA及热处理后的Cu-CHA在不同温度下对NO x的转化效率曲线如图3所示；
对比例2中H-AEI及热处理后的H-AEI在不同温度下对NO x的转化效率曲线如图4所示。
表1
Figure PCTCN2022112423-appb-000001
Figure PCTCN2022112423-appb-000002
表2
Figure PCTCN2022112423-appb-000003
由表1、表2与图1～4可得：
(1)以实施例1～5中得到的Cu-CHA与H-AEI的复合催化剂的NH 3-SCR催化反应的NO x转化效率较高，800℃水热处理后仍具有较高的NO x转化效率；本申请所述Cu-CHA与H-AEI的复合催化剂具有催化活性较强、水热稳定性较强、制备方法简单及制备成本低的优点，所述Cu-CHA与H-AEI的复合催化剂是一种高效稳定的NH 3-SCR催化剂。
(2)通过实施例1与实施例6和7的对比可知，本申请所述Cu-CHA沸石 与H-AEI沸石的质量比会影响NH 3-SCR催化反应的NO x转化效率；当Cu-CHA沸石与H-AEI沸石的质量比偏低时，会导致NO x转化效率降低，这是由于催化剂中活性位点不足导致催化活性下降；当Cu-CHA沸石与H-AEI沸石的质量比偏高时，会导致NO x转化效率升高，水热稳定性降低，这是由于催化剂中存在较多的铜，在水热老化之后，容易形成CuO x团聚，使骨架坍塌。
(3)通过实施例1与实施例8和9的对比可知，本申请所述Cu-CHA沸石中二氧化硅与氧化铝的摩尔比会影响NH 3-SCR催化反应的NO x转化效率；当Cu-CHA沸石中二氧化硅与氧化铝的摩尔比偏低时，会导致水热稳定性降低，这是由于硅铝比偏低，Cu-CHA体系中含量较多的铝，所以在水热老化时极易发生脱铝，使骨架结构被破坏，故其水热稳定性降低；当Cu-CHA沸石中二氧化硅与氧化铝的摩尔比偏高时，会导致NO x转化效率降低，水热稳定性降低，这是由于此时Cu-CHA催化剂中存在的酸性减少，活性位点较少。
(4)通过实施例1与实施例10和11的对比可知，本申请所述H-AEI沸石中二氧化硅与氧化铝的摩尔比会影响NH 3-SCR催化反应的NOx转化效率；当H-AEI沸石中二氧化硅与氧化铝的摩尔比偏高或偏低时，对活性影响不大，但是会降低水热稳定性。
(5)通过实施例2与对比例1及实施例1与对比例2的对比可知，本申请所述Cu-CHA沸石的NH 3-SCR活性较强，所述H-AEI沸石的NH 3-SCR活性较差，Cu-CHA沸石与H-AEI沸石混合的复合催化剂的催化活性较强，在Cu-CHA沸石中混入H-AEI沸石能够在保证较高NH 3-SCR催化活性的同时增强水热稳定性。
综上所述，本申请提供的Cu-CHA与H-AEI的复合催化剂具有与同样质量的Cu-CHA沸石相近的催化性能，所述复合催化剂的热稳定性优于同样质量的Cu-CHA沸石；在催化活性较强的Cu-CHA沸石中混入催化活性较差的H-AEI沸石能够在提升NH 3-SCR活性的同时增强水热稳定性；本申请提供的Cu-CHA与H-AEI的复合催化剂在≥250℃的条件下对NO x的净化效率为≥85％；所述复合催化剂在650～850℃的条件下水热处理10～120h，水热处理后的复合沸石SCR催化剂在≥250℃下对NO x的净化效率≥70％；本申请提供的Cu-CHA与H-AEI的复合催化剂具有催化活性较强、水热稳定性较强、制备方法简单及制备成本低的优点，所述Cu-CHA与H-AEI的复合催化剂是一种高效稳定的NH 3-SCR催 化剂。
以上所述仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，所属技术领域的技术人员应该明了，任何属于本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到的变化或替换，均落在本申请的保护范围和公开范围之内。

Claims (13)

  1. 一种Cu-CHA与H-AEI的复合催化剂，其中，所述复合催化剂包括Cu-CHA沸石与H-AEI沸石；
    所述复合催化剂在≥250℃的条件下对NO x的净化效率≥85％；
    所述复合催化剂在650～850℃的条件下热处理10～120h，水热处理后的复合沸石SCR催化剂在≥250℃下对NO x的净化效率≥70％。
  2. 根据权利要求1所述的复合催化剂，其中，所述Cu-CHA沸石与H-AEI沸石的质量比为(1～60):3，优选为(3～27):3。
  3. 一种如权利要求1或2所述复合催化剂的制备方法，其包括：
    混合Cu-CHA沸石与H-AEI沸石，得到所述复合催化剂。
  4. 根据权利要求3所述的制备方法，其中，所述Cu-CHA沸石是由双六元环以AABBCCAA顺序堆积而成，具有三维八元环孔道的CHA笼结构。
  5. 根据权利要求3或4所述的制备方法，其中，以Cu-CHA沸石的质量为基准，所述Cu-CHA沸石中含有质量分数为2.0wt％～10.0wt％的Cu，优选为3.5wt％～7.5wt％。
  6. 根据权利要求3～5任一项所述的制备方法，其中，所述Cu-CHA沸石中二氧化硅与氧化铝的摩尔比为(6～25):1，优选为(6～20):1。
  7. 根据权利要求3～6任一项所述的制备方法，其中，所述H-AEI沸石中二氧化硅与氧化铝的摩尔比为(10～40):1。
  8. 根据权利要求3～7任一项所述的制备方法，其中，所述混合包括液液混合、固液混合或固固混合中的任意一种或至少两种的组合。
  9. 根据权利要求9所述的制备方法，其中，所述固固混合包括研磨法和/或物理混合法。
  10. 根据权利要求3～9任一项所述的制备方法，其中，所述制备方法还包括Cu-CHA沸石的制备：
    (1)混合H-CHA与氯化铵溶液，过滤，烘干，得到中间体；
    (2)混合中间体与铜盐溶液，过滤，烘干后进行煅烧，得到所述Cu-CHA沸石。
  11. 根据权利要求10所述的制备方法，其中，步骤(1)所述混合的温度为20～50℃；
    优选地，步骤(1)所述H-CHA与氯化铵溶液的固液比为1:(5～30)，所述 固液比的单位为g/mL；
    优选地，步骤(1)所述氯化铵溶液的浓度为0.1～0.2mol/L；
    优选地，步骤(1)所述烘干的温度为80～120℃；
    优选地，步骤(2)所述混合的温度为20～60℃；
    优选地，步骤(2)所述中间体与铜盐溶液的固液比为1:(5～30)，所述固液比的单位为g/mL；
    优选地，所述铜盐溶液中的铜盐包括乙酸铜、硝酸铜或硫酸铜中的任意一种或至少两种的组合；
    优选地，步骤(2)所述铜盐溶液的浓度为0.01～0.3mol/L；
    优选地，步骤(2)所述烘干的温度为80～120℃；
    优选地，步骤(2)所述煅烧的温度为400℃～600℃，时间为5～8h。
  12. 一种如权利要求1或2所述复合催化剂的应用，其中，所述复合催化剂用于选择性催化还原柴油车尾气中氮氧化物。
  13. 根据权利要求12所述的应用，其中，所述复合催化剂与助剂混合后得到浆液，将浆液涂覆于蜂窝陶瓷，依次经干燥与焙烧后，用于选择性催化还原柴油车尾气中氮氧化物。
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