Light rare earth and potassium modified copper-based catalyst as well as preparation method and application thereof

Abstract

The invention discloses a light rare earth and potassium modified copper-based catalyst and a preparation method and application thereof, and belongs to the field of catalyst preparation and N2O emission reduction. The light rare earth and potassium modified copper-based catalyst provided by the invention is Kz-Cu / CexLa1-xO2 / Al2O3 and is composed of a gamma-Al2O3 carrier loaded with CeO2 and La2O3 and CuO and K loaded on the surface of the gamma-Al2O3 carrier, z is greater than or equal to 0.01 and less than or equal to 0.10, and x is greater than or equal to 0.1 and less than or equal to 0.9. The preparation method of the catalyst comprises the following steps: taking gamma-Al2O3 as a carrier, adding CeO2, La2O3 and ammonia water, and preparing CexLa1-xO2 / Al2O3 through a solid-phase impregnation method; a copper source and a potassium source are used as precursors, and the CexLa1-xO2 / Al2O3 is prepared into the Kz-Cu / CexLa1-xO2 / Al2O3 catalyst. The catalyst is simple in synthesis method and excellent in performance, high decomposition efficiency at a low temperature (300-400 DEG C) is realized when the catalyst is used as an N2O decomposition catalyst, and the catalyst has good impurity gas (including NOx, O2 and H2O) tolerance and thermal stability.

Description

Technical Field

[0001] The present invention belongs to the fields of catalyst preparation and NOx emission reduction, and particularly relates to a light rare earth and potassium modified copper-based catalyst, a preparation method thereof, and an application thereof. 2 Background Art

[0002] Disclosing the information of this background art section is only intended to enhance the understanding of the overall background of the present invention, and is not necessarily to be regarded as an admission or an implication in any form that this information constitutes the prior art already known to those of ordinary skill in the art.

[0003] In recent years, ammonia-hydrogen co-combustion based on on-vehicle hydrogen production has been widely studied for ammonia engines, effectively improving the carbon emission problem. However, due to the incomplete combustion of ammonia, some nitrogen oxides such as NOx (NOx, x = 1, 2) will be generated. Among them, N2O is considered to be one of the six major greenhouse gases, and its global warming potential is about 310 times that of CO2. The "Greenhouse Gas Bulletin 2023" released by the World Meteorological Organization shows that the concentration of N2O in the atmosphere has soared from about 270 ppb in 1984 to 335.8 ppb in 2022. Therefore, reducing the emissions of N2O remains a challenge. Selective absorption, thermal decomposition, direct catalytic decomposition, and selective catalytic reduction technology with a reducing agent are currently the main methods for removing N2O. Among them, the direct catalytic decomposition technology of N2O has good application prospects because of its simple operation, high decomposition efficiency, and ability to prevent secondary pollution. 2 x 2 2 2 2 2 2

[0004] 2 The decomposition reaction of N2O has been widely studied. In addition to noble metals, light rare earth elements usually serve as carriers to prepare catalysts for the N2O decomposition reaction due to their special intrinsic physical and chemical properties such as large ionic radius, adjustable 4f electrons, and low redox potential, and rich defect structures. In 1996, Tokyo Institute of Technology used Al2O3, MnO2, Fe2O3, Co3O4, SiO2, and CeO2 as carriers and loaded noble metals such as Ru, Pt, Pd, and Rh, and found that the Rh / CeO2 catalyst had the best N2O 2 2 3 2 3 2 3 3 4 2 2 2 ​​​​​​​​​​​​​​​​​​​​​​2 O catalytic decomposition performance. The National Chemical Institute of the United States studied nano-CuO / CeO 2 materials for their application in the N 2 O decomposition reaction. By using various catalyst characterization techniques, the effect of terminated CeO 2 crystal planes on the behavior of CuO dispersed on CeO 2 nano-cubes, nano-rods and polyhedral grains was studied in detail. The results showed that CeO 2 nano-rods loaded with 4 wt% Cu had the best N 2 O decomposition performance. Al 2 O 3 This metal oxide is usually studied as a support for supported catalysts. The Jagiellonian University added glycerol to the solution during the catalyst preparation and found that compared with the Co 3 O 4 / α-Al 2 O 3 catalyst obtained by aqueous solution impregnation, the Co 3 O 4 / α-Al 2 O 3 catalyst synthesized with glycerol assistance had excellent N 2 O decomposition activity.

[0005] However, although the existing supported catalysts have good N 2 O decomposition activity, there are generally some bottlenecks, such as low decomposition efficiency in the low temperature range (300 - 400 °C); many catalysts have poor tolerance to impurity gases. Therefore, it is urgently necessary to provide an N 2 O decomposition catalyst with good activity and tolerance to impurity gases (O x NO 2 and water vapor). Summary of the Invention

[0006] In order to solve the deficiencies of the prior art, the purpose of the present invention is to provide a light rare earth and potassium modified copper-based catalyst, its preparation method and application. The N 2 O decomposition catalyst provided by the present invention has a simple synthesis method and excellent performance, achieving high decomposition efficiency at low temperature (300 - 400 °C), and the catalyst has good tolerance to impurity gases (including NO x O 2 and H 2 O) and thermal stability.

[0007] In order to achieve the above purpose, the technical solution of the present invention is as follows: On the one hand, the present invention provides a light rare earth and potassium modified copper-based catalyst, and the light rare earth and potassium modified copper-based catalyst is Kz -Cu / Ce x La 1-x O 2 / Al 2 O 3 , by loading CeO 2 and La 2 O 3 γ-Al 2 O 3 The carrier and the CuO and K loaded on the surface thereof are composed of 0.01≤z≤0.10 and 0.1≤x≤0.9.

[0008] Preferably, 0.05≤z≤0.10, 0.3≤x≤0.6.

[0009] Preferably, the light rare earth and potassium modified copper-based catalyst has a micron particle shape with a particle size of 40 to 60 meshes.

[0010] In a second aspect, the present invention provides a method for preparing the above-mentioned light rare earth and potassium modified copper-based catalyst, comprising the following steps: (1) γ-Al 2 O 3 As carrier, CeO 2 ,La 2 O 3 and ammonia water to prepare Ce by solid phase impregnation method x La 1-x O 2 / Al 2 O 3 ; (2) Using copper source and potassium source as precursors, Ce x La 1-x O 2 / Al 2 O 3 Preparation of K z -Cu / Ce x La 1-x O 2 / Al 2 O 3 catalyst.

[0011] In one or more embodiments, in step (1), the γ-Al 2 O 3 By Al 2 O 3 The obtained product is calcined under a mixed atmosphere.

[0012] Furthermore, the mixed atmosphere is H 2 / Ar mixed gas, hydrogen accounts for 5-20% of the mixed gas.

[0013] Further, the calcination temperature is 500 - 600 °C, the calcination time is 8 - 12 h, and the heating rate is 3 - 6 °C / min.

[0014] In one or more embodiments, in step (1), the added CeO 2 and La 2 O 3 , the Ce:La molar ratio is (0.1~0.9):(0.1~0.9), preferably (0.3~0.6):(0.4~0.7), and more preferably (0.4~0.5):(0.5~0.6).

[0015] In one or more embodiments, in step (1), using γ-Al 2 O 3 as the carrier, the CeO 2 loading is 10~30 wt.%, preferably 15 - 25 wt.%; the La 2 O 3 loading is 10~30 wt.%, preferably 15 - 25 wt.%.

[0016] In one or more embodiments, in step (1), the concentration of the ammonia water is 25~28 wt.%. The dosage ratio of ammonia water and γ-Al 2 O 3 is (4 - 6 mL):(4 - 5 g).

[0017] In one or more embodiments, in step (1), the specific preparation method of the solid-phase impregnation method is: Mix CeO 2 and La 2 O 3 in water, then successively add γ-Al 2 O 3 and ammonia water, remove the moisture, and obtain Ce x La 1- x O 2 / Al 2 O 3 after drying and calcining.

[0018] Further, using Al 2 O 3 as the carrier, the loading of Ce x La 1-x O 2 is 10 - 30 wt.%, preferably 15 - 25 wt.%.

[0019] Further, the removal of moisture is by water bath evaporation, and the evaporation temperature is 70 - 90 °C.

[0020] Further, the drying is drying by baking, the drying temperature is 90-110 °C, and the drying time is 10-14 h.

[0021] Further, the calcination is carried out at a calcination temperature of 350-550 °C, a calcination time of 4-8 h, and a heating rate of 1-4 °C / min.

[0022] In one or more embodiments, in step (2), the copper source is copper citrate and the potassium source is potassium carbonate.

[0023] In one or more embodiments, in step (2), for K z -Cu / Ce x La 1-x O 2 / Al 2 O 3 For the catalyst, the loading amount of CuO is 10-30 wt.%, preferably 10-20 wt.%, the loading amount of K metal is 0.01-10 wt.%, preferably 0.01-0.10 wt.%, and more preferably 0.05-0.10 wt.%.

[0024] In one or more embodiments, in step (2), using the copper source and potassium source as precursors, Ce x La 1-x O 2 / Al 2 O 3 is prepared into K z -Cu / Ce x La 1-x O 2 / Al 2 O 3 The specific preparation method of the catalyst is as follows: Mix the copper source, potassium source and Ce x La 1-x O 2 / Al 2 O 3 support, dry and then calcine to obtain K z -Cu / Ce x La 1-x O 2 / Al 2 O 3 catalyst.

[0025] Further, the mixing is grinding, and the grinding time is 1-3 h.

[0026] Further, the drying is drying by baking, the drying temperature is 90-110 °C, and the drying time is 10-14 h.

[0027] Further, the calcination is carried out at a calcination temperature of 550-650 °C, a calcination time of 4-8 h, and a heating rate of 1-4 °C / min.

[0028] Thirdly, the present invention provides the application of the above-mentioned light rare earth and potassium modified copper-based catalyst in the decomposition of N 2 O.

[0029] Fourthly, the present invention provides a method for low-temperature catalytic decomposition of N 2 O, which adopts the above-mentioned light rare earth and potassium modified copper-based catalyst, and includes the following steps: carried out in a fixed-bed reactor, adding the above-mentioned K z -Cu / Ce x La 1-x O 2 / Al 2 O 3 catalyst into a quartz tube reactor, introducing N 2 O, and carrying out decomposition at 300 °C to 400 °C.

[0030] Preferably, the low temperature is 350 °C to 400 °C.

[0031] The principle of the present invention is as follows: The present invention provides a light rare earth and potassium modified copper-based catalyst for low-temperature catalytic decomposition of N 2 O. Under the promotion of ammonia water, rare earth oxides CeO 2 O 3 and La 2 O 2 are loaded on the γ-Al 3 O x La 1-x O 2 / Al 2 O 3 support. Different impregnation amounts of CuO and metal K ions are loaded on the Ce x La 1- x O 2 / Al 2 O 3 support with different Ce / La molar ratios by solid-phase impregnation method. Due to the characteristics of rare earth elements such as large ionic radius, adjustable 4f electrons, low redox potential and rich defect structure, and the unique chemisorption properties of transition metal-based oxides, that is, the existence of partially filled d shells of metal ions, there is a strong electronic interaction between the Ce 2 O

[0032] A specific implementation process of the present invention is as follows: First, Al2 O 3 Put it into a tubular furnace, and introduce a 10% H 2 / Ar mixed gas, and heat it up to 550 °C at a heating rate of 5 °C / min for 10 h. Mark the treated Al 2 O 3 support as γ-Al 2 O 3 . Prepare the Ce x La 1-x O 2 / Al 2 O 3 support by the impregnation method, that is, dissolve a certain amount of cerium acetate and lanthanum acetate in deionized water, stir for 1 h, then add γ-Al 2 O 3 , stir for 1 h, then add 5 mL of concentrated ammonia water (25 - 28 wt.%), and continue to stir for 1 h. Then evaporate to dryness in a water bath at 80 °C. Dry in an oven at 90 - 110 °C for 12 h. Calcinate in a muffle furnace at 350 - 550 °C for 4 - 8 h, with a heating rate of 2 °C / min. Prepare the Cu / Ce x La 1-x O 2 / Al 2 O 3 catalyst with copper citrate as the precursor and a CuO loading of 15 wt.%. Grind copper citrate and Ce x La 1-x O 2 / Al 2 O 3 support together for 2 h, then dry in an oven at 90 - 110 °C for 12 h. Calcinate in a muffle furnace at 550 - 650 °C for 4 - 8 h, with a heating rate of 2 °C / min. Prepare the K z -Cu / Ce x La 1-x O 2 / Al 2 O 3 catalyst with potassium carbonate and copper citrate as the precursors, a CuO loading of 15 wt.%, and K metal masses of 0.01 wt.%, 0.03 wt.%, 0.05 wt.%, 0.08 wt.%, and 0.10 wt.%. Grind copper citrate, potassium carbonate and Ce x La 1-x O 2 / Al 2 O 3 support together for 2 h, then dry in an oven at 90 - 110 °C for 12 h. Calcinate in a muffle furnace at 550 - 650 °C for 4 - 8 h, with a heating rate of 2 °C / min.

[0033] One or some of the above technical solutions have the following advantages or beneficial effects: (1) The K z -Cu / Ce x La 1-x O 2 / Al 2 O 3 catalyst provided by the present invention, due to the strong electronic interaction between the Ce x La 1-x O 2 / Al 2 O 3 support and CuO, and the incorporation of alkali metal K improves the basicity of the catalyst, thereby promoting the decomposition performance of the catalyst and achieving excellent catalytic N 2 O decomposition performance at low temperatures (300 - 400 °C).

[0034] (2) The K z -Cu / Ce x La 1-x O 2 / Al 2 O 3 catalyst provided by the present invention, when used as an N 2 O decomposition catalyst, has excellent N 2 O decomposition performance under low-temperature (300 - 400 °C) conditions, strong tolerance to impurity gases (including NO x , O 2 and H 2 O), and good thermal stability. When O 2 , NO x and H 2 O are introduced at 450 °C, its N 2 O decomposition efficiency only drops from 100% to 98%; especially at 375 °C, when the three impurity gases coexist, the N 2 O decomposition efficiency of the catalyst can still reach over 75%.

[0035] (3) The K z -Cu / Ce x La 1-x O 2 / Al 2 O 3 catalyst provided by the present invention has a simple synthesis method, a short cycle, and the required raw materials are simple, easily available, and inexpensive. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The specification drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0037] Figure 1 The Cu / Al prepared in the embodiments of the present invention 2 O 3 、Cu / Ce / Al 2 O 3 、Cu / La / Al 2 O 3 catalysts and the N x La 1-x / Al 2 O 3 decomposition reaction activity of the catalysts with temperature change; 2 Figure 2 The N 2 O 3 decomposition reaction activity of the Cu / CeLa / Al 2 catalysts with different K ion impregnation amounts in the embodiments of the present invention with temperature change; Figure 3 The O 0.05 -Cu / Ce 0.5 La 0.5 / Al 2 O 3 tolerance test results of the catalyst at 375 °C, 400 °C, 425 °C and 450 °C for O 2 +NO x +H 2 O; Figure 4 The N z / Ce x La 1-x O 2 / Al 2 O 3 reaction activity diagram of the catalyst with temperature change in Comparative Example 1 of the present invention; 2 Figure 5 The N 2 reaction activity diagram of the traditional Fe-ZSM-5 catalyst with temperature change in Comparative Example 2 of the present invention; Figure 6 The Cu / Al 2 O 3 、K z -Cu / Al 2 O 3 and the O z -Cu / Ce x La 1-x O 2 / Al 2 O 3 ​​XRD pattern of the catalyst; Figure 7 K prepared in the embodiment of the present invention 0.08 -Cu / CeO 2 / Al 2 O 3 、K 0.08 -Cu / La 2 O 3 / Al 2 O 3 、K 0.08 -Cu / Ce 0.7 La 0.3 O 2 / Al 2 O 3 、K 0.08 -Cu / Ce 0.5 La 0.5 O 2 / Al 2 O 3 SEM images of the catalyst at different magnifications; among them, (A)-(D) are K 0.08 -Cu / CeO 2 / Al 2 O 3 、K 0.08 -Cu / La 2 O 3 / Al 2 O 3 、K 0.08 -Cu / Ce 0.7 La 0.3 O 2 / Al 2 O 3 、K 0.08 -Cu / Ce 0.5 La 0.5 O 2 / Al 2 O 3 , (A1) is the detailed enlarged view of (A), (B1) is the detailed enlarged view of (B), (C1) is the detailed enlarged view of (C), and (D1) is the detailed enlarged view of (D); Figure 8 K prepared in the embodiment of the present invention 0.08 -Cu / Ce 0.3 La 0.7 O 2 / Al 2 O 3 、K 0.08 -Cu / Al 2 O 3 、Cu / Al 2 O 3SEM images of the catalyst at different magnifications; among them, (E)-(G) are K 0.08 -Cu / Ce 0.3 La 0.7 O 2 / Al 2 O 3 、K 0.08 -Cu / Al 2 O 3 、Cu / Al 2 O 3 , (E1) is the detailed enlarged view of (E), (F1) is the detailed enlarged view of (F), and (G1) is the detailed enlarged view of (G); Figure 9 K 0.08 -Cu / CeO 2 / Al 2 O 3 、K 0.08 -Cu / La 2 O 3 / Al 2 O 3 、K 0.08 -Cu / Ce 0.7 La 0.3 O 2 / Al 2 O 3 EDX-Mapping images of the catalyst; among them, (A)-(C) are K 0.08 -Cu / CeO 2 / Al 2 O 3 、K 0.08 -Cu / La 2 O 3 / Al 2 O 3 、K 0.08 -Cu / Ce 0.7 La 0.3 O 2 / Al 2 O 3 ; Figure 10 K 0.08 -Cu / Ce 0.5 La 0.5 O 2 / Al 2 O 3 、K 0.08 -Cu / Ce 0.3 La 0.7 O 2 / Al 2 O3 , K 0.08 -Cu / Al 2 O 3 Catalyst EDX-Mapping images; among them, (D)-(F) are K 0.08 -Cu / Ce 0.5 La 0.5 O 2 / Al 2 O 3 , K 0.08 -Cu / Ce 0.3 La 0.7 O 2 / Al 2 O 3 , K 0.08 -Cu / Al 2 O 3 ; Figure 11 This is the EDX-Mapping image of the Cu / Al 2 O 3 catalyst prepared in the embodiment of the present invention. Specific embodiments

[0038] Cu / Ce 0.5 La 0.5 / Al 2 O 3 The catalyst can be abbreviated as Cu / CeLa / Al 2 O 3 .

[0039] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in conjunction with specific embodiments.

[0040] Example 1 Carrier Al 2 O 3 Pretreatment Put 50 g of Al 2 O 3 into a tubular furnace, introduce a 10% H 2 / Ar mixed gas, and raise the temperature to 550 °C at a heating rate of 5 °C / min for 10 h. The treated Al 2 O 3 carrier is marked as γ-Al 2 O 3 .

[0041] Example 2 Preparation of CeO 2 / Al 2 O 3 Carrier Dissolve 3.02 g of cerium acetate in 6 ml of deionized water. After stirring for 1 h, add 4.8 g of γ-Al obtained by treating Example 1 2 O 3 , stir for 1 h, then add 5 mL of concentrated ammonia water (26 wt.%). Continue stirring for 1 h. Then evaporate to dryness in a water bath at 80 °C and dry in an oven at 110 °C for 12 h. Calcinate the obtained sample in a muffle furnace at a heating rate of 2 °C / min to 550 °C for 4 h. Mark the obtained support as CeO 2 / Al 2 O 3 . The CeO 2 loading is 20 wt.%.

[0042] Example 3 Preparation of La 2 O 3 / Al 2 O 3 support Dissolve 1.59 g of lanthanum acetate in 6 ml of deionized water. After stirring for 1 h, add 4.8 g of γ-Al obtained by treating Example 1 2 O 3 , stir for 1 h, then add 5 mL of concentrated ammonia water (26 wt.%). Continue stirring for 1 h. Then evaporate to dryness in a water bath at 80 °C and dry in an oven at 110 °C for 12 h. Calcinate the obtained sample in a muffle furnace at a heating rate of 2 °C / min to 550 °C for 4 h. Mark the obtained support as La 2 O 3 / Al 2 O 3 . The La 2 O 3 loading is 20 wt.%.

[0043] Example 4 Preparation of Ce x La 1-x O 2 / Al 2 O 3 supports with different Ce / La molar ratios Dissolve lanthanum acetate and cerium acetate in 6 ml of deionized water. After stirring for 1 h, add γ-Al obtained by treating Example 1 2 O 3 , stir for 1 h, then add 5 mL of concentrated ammonia water (25 - 28 wt.%). Continue stirring for 1 h. Then evaporate to dryness in a water bath at 80 °C and dry in an oven at 110 °C for 12 h. Calcinate the obtained sample in a muffle furnace at a heating rate of 2 °C / min to 550 °C for 4 h. Mark the obtained support as Ce x La 1-x O 2 / Al 2 O 3 (0 ≤ x ≤ 1). Cex La 1-x O 2 The loading amount is 20 wt.%.

[0044] Preparation of the copper oxide-containing catalyst in Example 5 Cu / Ce was prepared by the solid-phase impregnation method x La 1-x O 2 / Al 2 O 3 catalyst. Using copper citrate as the precursor, the CuO loading amount is 15 wt.%. The specific method is to grind copper citrate with γ-Al 2 O 3 in Example 1, CeO 2 / Al 2 O 3 in Example 2, La 2 O 3 / Al 2 O 3 in Example 3, Ce x La 1-x O 2 / Al 2 O 3 supports in Example 4 together for 2 h, and dry in an oven at 110 °C for 12 h. The obtained sample was calcined in a muffle furnace at a heating rate of 2 °C / min to 650 °C for 4 h.

[0045] Preparation of the potassium-doped copper oxide-containing catalyst in Example 6 K z -Cu / Ce x La 1-x O 2 / Al 2 O 3 catalyst was prepared by the solid-phase impregnation method. Using potassium carbonate and copper citrate as the precursors, the CuO loading amount is 15 wt.%, and the K metal mass (0 ≤ z ≤ 0.1) is 0 wt.%, 0.01 wt.%, 0.03 wt.%, 0.05 wt.%, 0.08 wt.%, 0.10 wt.% respectively. Grind copper citrate, potassium carbonate and Ce x La 1-x O 2 / Al 2 O 3 support in Example 4 together for 2 h, and dry in an oven at 110 °C for 12 h. The obtained sample was calcined in a muffle furnace at a heating rate of 2 °C / min to 650 °C for 4 h to obtain K z -Cu / Ce x La 1-x O 2 / Al 2 O3 Catalyst

[0046] Comparative Example 1 Different from Example 6, a catalyst without copper element was prepared, namely K z / Ce x La 1-x O 2 / Al 2 O 3 Catalyst (1) Using γ-Al 2 O 3 as the carrier, CeO 2 , La 2 O 3 and ammonia water were added, and Ce x La 1-x O 2 / Al 2 O 3 carrier was prepared by solid-phase impregnation method; (2) Using potassium source as the precursor, Ce x La 1-x O 2 / Al 2 O 3 was prepared into K z / Ce x La 1-x O 2 / Al 2 O 3 catalyst.

[0047] Figure 4 is the N z / Ce x La 1-x O 2 / Al 2 O 3 reaction activity diagram of the K 2 / Ce z La x O 1-x / Al 2 O 2 changing with temperature. The K 3 / Ce 0.08 La 0.7 O 0.3 / Al 2 O 2 / Al 3 O 0.08 / Ce 0.3 La 0.7 O 2 / Al 2 O 3 and K0.08 / Ce 0.5 La 0.5 O 2 / Al 2 O 3 。

[0048] Comparative Example 2 Using the room-temperature ion-exchange method, H-ZSM-5 (Si:Al = 300) was added to 10 mL of 0.012 g / mL Fe(NO 3 ) 3 solution, stirred at room temperature for 12 h, washed, centrifuged, dried at 110 °C for 12 h, and the precursor material was calcined in air at 550 °C for 4 h to prepare an Fe-ZSM-5 catalyst.

[0049] Figure 5 This is the N 2 O reaction activity diagram of the traditional Fe-ZSM-5 catalyst as a function of temperature.

[0050] Figure 6 This is the XRD pattern of the potassium-doped copper oxide-containing catalyst prepared in Example 6, all showing the corresponding diffraction peaks of CuO, and no diffraction peaks caused by species such as cerium oxide and lanthanum oxide were detected. This may be due to the low doping amount of Ce or La or their uniform dispersion.

[0051] Figures 7 - 8 For Cu / Al 2 O 3 、K z -Cu / Al 2 O 3 and K z -Cu / Ce x La 1-x O 2 / Al 2 O 3 SEM images of the catalysts at different magnifications; among them, (A)-(G) are K 0.08 -Cu / CeO 2 / Al 2 O 3 、K 0.08 -Cu / La 2 O 3 / Al 2 O 3 、K 0.08 -Cu / Ce 0.7 La 0.3 O 2 / Al 2 O 3 、K 0.08 -Cu / Ce 0.5 La0.5 O 2 / Al 2 O 3 、K 0.08 -Cu / Ce 0.3 La 0.7 O 2 / Al 2 O 3 、K 0.08 -Cu / Al 2 O 3 、Cu / Al 2 O 3 , (A1) is the detailed enlarged view of (A), (B1) is the detailed enlarged view of (B), (C1) is the detailed enlarged view of (C), (D1) is the detailed enlarged view of (D), (E1) is the detailed enlarged view of (E), (F1) is the detailed enlarged view of (F), and (G1) is the detailed enlarged view of (G).

[0052] Figures 9 - 11 is Cu / Al 2 O 3 、K z -Cu / Al 2 O 3 and K with different Ce / La molar ratios z -Cu / Ce x La 1-x O 2 / Al 2 O 3 Catalyst EDX-Mapping images; among them, (A)-(G) are K 0.08 -Cu / CeO 2 / Al 2 O 3 、K 0.08 -Cu / La 2 O 3 / Al 2 O 3 、K 0.08 -Cu / Ce 0.7 La 0.3 O 2 / Al 2 O 3 、K 0.08 -Cu / Ce 0.5 La 0.5 O 2 / Al 2 O 3 、K 0.08 -Cu / Ce 0.3 La 0.7 O 2 / Al 2 O3 , K 0.08 -Cu / Al 2 O 3 , Cu / Al 2 O 3 .

[0053] The results show that the obtained K z -Cu / Ce x La 1-x O 2 / Al 2 O 3 catalyst is in the form of micron particles, and elements such as Ce, La, Al, O, Cu, and K are uniformly dispersed.

[0054] Test on the N 2 O decomposition reaction activity of the catalyst in Application Example 1 200 mg of the required catalyst was tableted into fine particles (size 40 - 60 mesh). Subsequently, a small amount of quartz wool was added to the fixed-bed reactor, the catalyst was placed above the quartz wool, and then a small amount of quartz wool was filled above the catalyst particles. The concentration of the reaction gas component N 2 O was adjusted to 5000 ppm, the total gas flow rate was maintained at 100 mL·min -1 , and the gas hourly space velocity was 30000 mL·g -1 ·h -1 . The test was carried out using Gasmate. Before the test, the reaction gas was switched to bypass the sample tube and directly enter the detection system to ensure that the configured gas concentration reached the set value. Subsequently, the reaction gas was switched back to pass through the fixed-bed reactor and through the catalyst to be tested. Finally, a temperature control program was set, with a heating rate of 5℃·min -1 , and it was held at each temperature point for 0.5 h, and the composition of the outlet tail gas was detected in real time by infrared.

[0055] Test on the O 2 tolerance of the catalyst during the N 2 O decomposition reaction in Application Example 2 x +NO 2 +H 200 mg of the required catalyst was tableted into fine particles (size 40 - 60 mesh). Subsequently, a small amount of quartz wool was added to the fixed-bed reactor, the catalyst was placed above the quartz wool, and then a small amount of quartz wool was filled above the catalyst particles. The concentrations of the reaction gas components N 2 O, NO x , O 2 , H 2 O were adjusted to 5000 ppm, 1000 ppm, 5 vol%, and 10 vol% respectively, and the total gas flow rate was maintained at 100 mL·min-1 , the gas hourly space velocity is 30000 mL·g -1 ·h -1 . At 5 h of the reaction, NO x , O 2 and H 2 O are introduced. Before the test, the reaction gas is switched to bypass the sample tube and directly enter the detection system to ensure whether the configured gas concentration reaches the set value. Subsequently, the reaction gas is switched back to pass through the fixed-bed reactor and through the catalyst to be tested. Finally, the reaction temperatures are set to 375 °C, 400 °C, 425 °C, and 450 °C respectively, and the test duration is 45 h.

[0056] Figure 1 is Cu / Al 2 O 3 , Cu / Ce / Al 2 O 3 , Cu / La / Al 2 O 3 catalysts and Cu / Ce with different Ce / La molar ratios x La 1-x / Al 2 O 3 catalysts for the N 2 O decomposition reaction activity varying with temperature. Cu / Al 2 O 3 has almost no decomposition activity below 500 °C, Cu / Ce / Al 2 O 3 starts to have decomposition activity at 425 °C, and Cu / La / Al 2 O 3 starts to have decomposition activity at 400 °C. Cu / Ce x La 1-x / Al 2 O 3 catalysts have better decomposition activity, especially Cu / Ce 0.5 La 0.5 O 2 / Al 2 O 3 catalysts, whose T 10 (the temperature at which the N 2 O decomposition efficiency reaches 10%), T 50 (the temperature at which the N 2 O decomposition efficiency reaches 50%), and T 90 (the temperature at which the N 2 O decomposition efficiency reaches 90%) are 325 °C, 375 °C, and 425 °C respectively.

[0057] Figure 2 is Cu / Ce with different K ion impregnation amounts0.5 La 0.5 / Al 2 O 3 The catalytic activity of the catalyst (abbreviated as K-Cu / CeLa / Al 2 O 3 ) for the decomposition reaction of NO with temperature change. The Cu / Ce 2 La 0.5 La 0.5 / Al 2 O 3 catalyst doped with K shows a significantly improved catalytic activity. With the increase of K doping amount, the NO decomposition activity of the catalyst shows a volcano-shaped trend. The best activity is shown by the K 2 -Cu / Ce 0.05 -Cu / Ce 0.5 La 0.5 O 2 / Al 2 O 3 catalyst, and its T 10 、T 50 and T 90 are 250 °C, 300 °C and 350 °C respectively.

[0058] Figure 3 For the K 0.05 -Cu / Ce 0.5 La 0.5 / Al 2 O 3 catalyst, the O 2 +NO x +H 2 O tolerance test results at 375 °C, 400 °C, 425 °C and 450 °C are shown. The K 0.05 -Cu / Ce 0.5 La 0.5 / Al 2 O 3 catalyst has good tolerance to impurity gases at several temperature points. At 375 °C, after introducing O 2 , NO x and H 2 O, its NO decomposition activity drops to about 77%. With the increase of temperature, the tolerance of the catalyst to impurity gases improves. At 450 °C, after introducing O 2 O, its NO decomposition efficiency only drops from 100% to 98%. This indicates that the K 2 O x and H 2 O 2 -Cu / Ce 0.05 -Cu / Ce 0.5 La 0.5 / Al 2 O 3The catalyst has extremely excellent tolerance to impurity gases.

[0059] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A light rare earth and potassium modified copper-based catalyst, characterized in that: The light rare earth and potassium modified copper-based catalyst is K z -Cu / Ce x La 1-x O2 / Al2O3 is composed of a γ-Al2O3 carrier loaded with CeO2 and La2O3 and CuO and K loaded on its surface, wherein 0.01≤z≤0.10, 0.1≤x≤0.

9.

2. The light rare earth and potassium modified copper-based catalyst according to claim 1, characterized in that: 0.05≤z≤0.10, 0.3≤x≤0.6; The particle size of the light rare earth and potassium modified copper-based catalyst is 40-60 meshes.

3. A method for preparing the light rare earth and potassium modified copper-based catalyst according to claim 1 or 2, characterized in that: The following steps are involved: (1) CeO2, La2O3 and ammonia were added to γ-Al2O3 as the carrier to prepare Ce by solid phase impregnation method. x La 1-x O2 / Al2O3; (2) Using copper source and potassium source as precursors, Ce x La 1-x Preparation of K from O2 / Al2O3 z -Cu / Ce x La 1-x O2 / Al2O3 catalyst.

4. The preparation method according to claim 3, characterized in that: In step (1), the γ-Al2O3 is obtained by calcining Al2O3 under a mixed atmosphere; The mixed atmosphere is H2 / Ar mixed gas, and hydrogen accounts for 5-20% of the mixed gas; The calcination temperature is 500-600°C, the calcination time is 8-12h, and the heating rate is 3-6°C / min.

5. The preparation method according to claim 3, characterized in that: In step (1), CeO2 and La2O3 are added, and the molar ratio of Ce:La is (0.1~0.9):(0.1~0.9); In step (1), γ-Al2O3 is used as a carrier, and the CeO2 loading amount is 10~30wt.%; the La2O3 loading amount is 10~30wt.%; In step (1), the concentration of the ammonia water is 25-28 wt.%; the usage ratio of the ammonia water and γ-Al2O3 is (4-6 mL):(4-5 g).

6. The preparation method according to claim 3, characterized in that: In step (1), the specific preparation method of the solid phase impregnation method is: CeO2 and La2O3 are added to water and mixed, and then γ-Al2O3 and ammonia water are added in sequence, and the water is removed, and then dried and calcined to obtain Ce x La 1-x O2 / Al2O3; The water removal is performed by water bath evaporation at a temperature of 70-90°C; The drying temperature is 90~110℃ and the drying time is 10~14h; The calcination temperature is 350~550℃, the calcination time is 4~8h, and the heating rate is 1~4℃ / min.

7. The preparation method according to claim 3, characterized in that: In step (2), the copper source is copper citrate, and the potassium source is potassium carbonate; In step (2), for K z -Cu / Ce x La 1-x For O2 / Al2O3 catalyst, the CuO loading is 10~30wt.%, and the K metal loading is 0.01~10wt.%.

8. The preparation method according to claim 3, characterized in that: In step (2), the copper source and potassium source are used as precursors to x La 1-x Preparation of K from O2 / Al2O3 z -Cu / Ce x La 1-x The specific preparation method of O2 / Al2O3 catalyst is as follows: copper source, potassium source and Ce x La 1-x O2 / Al2O3 carriers are mixed and dried and calcined to obtain K z -Cu / Ce x La 1-x O2 / Al2O3 catalyst; The mixing is grinding, and the grinding time is 1 to 3 hours; The drying temperature is 90~110℃ and the drying time is 10~14h; The calcination temperature is 550~650℃, the calcination time is 4~8h, and the heating rate is 1~4℃ / min.

9. Use of the light rare earth and potassium modified copper-based catalyst according to claim 1 or 2 or the light rare earth and potassium modified copper-based catalyst obtained by the preparation method according to any one of claims 3 to 8 in catalyzing the decomposition of N2O.

10. A method for low temperature catalytic decomposition of N2O, characterized in that: The light rare earth and potassium modified copper-based catalyst according to claim 1 or 2 or the light rare earth and potassium modified copper-based catalyst obtained by the preparation method according to any one of claims 3 to 8 is used, comprising the following steps: In a fixed bed reactor, K was added to the quartz tube reactor. z -Cu / Ce x La 1-x O2 / Al2O3 catalyst, N2O is introduced and decomposed at 300℃~400℃.

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