A perovskite / ceria type catalyst, its preparation method and application

Abstract

The application discloses a perovskite / cerium oxide type catalyst and a preparation method and application thereof. The perovskite / cerium oxide type catalyst comprises active component perovskite ABO3 and carrier cerium oxide CeO2, the active component perovskite ABO3 accounts for 3wt%-10wt% of the total mass of the catalyst, and the carrier cerium oxide CeO2 is spherical and has a {220} crystal face exposure ratio of 60%-90%. The preparation method is as follows: (1) cerium nitrate is dissolved in an ethanol solution and heated, and then triethylene tetramine is added; (2) an ammonia water solution is added to adjust the pH value, and hydrothermal reaction, aging, filtering, washing, drying and calcining of the solid precipitate are carried out to obtain the spherical cerium oxide carrier; and (3) a perovskite active component impregnation solution is prepared to impregnate the carrier, and drying and calcining are carried out to obtain the catalyst. The application strengthens the strong interaction between the active site and the carrier by regulating the carrier morphology and the crystal face, realizes high-efficiency direct decomposition of NO in high-temperature flue gas, and is especially suitable for flue gas denitrification of high-temperature flue gas generated by industrial furnaces and kilns.

Description

Technical Field

[0001] This invention belongs to the field of industrial flue gas purification and denitrification technology, specifically relating to a perovskite / cerium oxide type catalyst for direct decomposition and denitrification of NO, its preparation method, and its application. Background Technology

[0002] Nitrogen oxides (NO) x Of the total nitrogen (NOx), approximately 95% comes from a wide range of sources, with human activities and production contributing the majority of NOx. x Emissions are a major contributor to environmental pollution (acid rain, ozone depletion, photochemical smog, etc.). Currently, selective catalytic reduction (NH3-SCR) of ammonia is a relatively mature denitrification technology used in stationary sources such as industrial furnaces and kilns. Although its application temperature is relatively low (300~500℃), this technology uses ammonia as a reducing agent, and the high ammonia-to-nitrogen ratio leads to NH3 leakage, high consumption, and a high risk of secondary pollution, pipeline corrosion, severe scaling, and high equipment and operating costs. Considering the actual operating conditions of high-temperature flue gas (800℃) generated by the new dry-process cement production and the high-temperature flue gas (700~800℃) generated at the tail end of the gasification cooling flue in converter steelmaking, existing NH3-SCR catalysts are prone to sintering, and the reducing agent ammonia is easily decomposed, resulting in low denitrification efficiency. This technology is not suitable for high-temperature flue gas denitrification. Direct NO decomposition denitrification directly converts NO into N2 and O2 without using a reducing agent. It has outstanding advantages such as clean and environmentally friendly products, no secondary pollution, small equipment size, simple process, and good economic efficiency, making it the most ideal and environmentally friendly denitrification technology.

[0003] The direct decomposition reaction of NO is thermodynamically feasible (∆G = -86.6 kJ / mol, 100). o However, the high activation energy barrier (364 kJ / mol) limits the reaction kinetics. Therefore, designing and developing highly efficient NO direct decomposition catalysts is crucial for this denitrification technology. To date, publicly reported NO direct decomposition catalysts mainly include noble metals, metal oxides, molecular sieves, and perovskite catalysts. Among these, the first three types of catalysts are unsuitable for high-temperature flue gas denitrification in dry cement and converter steelmaking due to their poor high-temperature activity, susceptibility to sintering, and poor resistance to O2 poisoning. In contrast, perovskite catalysts typically exhibit higher NO direct decomposition activity at high temperatures of 700-850℃.

[0004] Current published literature involves the direct catalysis of NO to N2 and O2 using perovskite catalysts, but the main research focuses on the effects of changes in perovskite loading (ChemCatChem, 2020, 12, 4297–4303) and B-site doping of perovskite (ChemCatChem, 2016, 8, 417–425) on NO decomposition activity. CN113134352 discloses a composite metal oxide catalyst for the direct decomposition of nitrogen oxides and its preparation method. This method compares the preparation of xBaBO3-MO2 catalyst by one-pot method, impregnation method and mechanical mixing method. The catalyst prepared by one-pot method can be used at 800℃ with a low space velocity of 1.5 g·s / cm. 3 At this stage, the conversion rate of NO to N2 was 75.6%. Due to the poor dispersion of perovskite active sites, it was difficult to achieve a significant breakthrough in NO decomposition efficiency, and the reaction space velocity also needed to be improved. Therefore, how to further improve the direct decomposition and denitrification efficiency of NO in catalysts, realize the efficient direct decomposition and denitrification of NO in high-temperature flue gas, and promote energy conservation and emission reduction in industrial furnaces is an urgent technical problem to be solved. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a perovskite / cerium oxide type catalyst, its preparation method, and its applications. By controlling the morphology and crystal facets of the support, this invention enhances the strong interaction between the active site and the support, achieving efficient and direct decomposition of NO in high-temperature flue gas. It is particularly suitable for denitrification of high-temperature flue gas generated by industrial furnaces and kilns.

[0006] The perovskite / cerium oxide catalyst of the present invention comprises an active component of perovskite ABO3 and a support of cerium oxide CeO2, wherein the A-site is one or more of Ba, La, and Sr, preferably Ba, and the B-site is one or more of Cu, Mn, Ni, Co, Fe, K, and Mg, preferably Co, and the molar ratio of A to B is 1-5:1; the active component of perovskite ABO3 accounts for 3wt%-10wt% of the total mass of the catalyst; the catalyst is spherical with an average particle size of 120-180 nm, an {220} crystal face exposure ratio of 60%-90%, and a specific surface area of ​​20-35 m². 2 / g.

[0007] The preparation method of the perovskite / cerium oxide type catalyst of the present invention includes the following: (1) dissolving cerium nitrate in an ethanol solution and heating it to 50-95°C, then adding triethylenetetramine and mixing it evenly; (2) adding an ammonia solution to adjust the pH value to 8-11, carrying out a hydrothermal reaction, and then aging it. After aging, the solid precipitate is filtered, washed, dried and calcined to obtain a spherical cerium oxide support; (3) preparing a perovskite active component impregnation solution, then impregnating the spherical cerium oxide support with the impregnation solution, drying and calcining to obtain a perovskite / cerium oxide type catalyst.

[0008] In the method of the present invention, the molar ratio of triethylenetetramine to cerium nitrate in step (1) is 1~3:1.

[0009] In the method of the present invention, the mixing uniformity method in step (1) is microwave ultrasonic or magnetic stirring.

[0010] In the method of this invention, the hydrothermal reaction conditions in step (2) are: time of 2-8 hours, temperature of 80-200℃, and the reaction is generally carried out in a reaction vessel. The aging conditions are: aging time of 10-24 hours, and aging temperature of 20-30℃.

[0011] In the method of the present invention, the washing process in step (2) generally uses deionized water and ethanol to wash until neutral.

[0012] In the method of the present invention, the drying conditions in step (2) are: drying temperature of 80~140℃ and drying time of 6~12 hours; the calcination conditions in step (2) are: calcination temperature of 400~600℃ and calcination time of 2~6 hours.

[0013] In the method of this invention, the preparation of the perovskite active component impregnation solution in step (3) is well known to those skilled in the art. It is generally prepared using soluble salts of A and B, such as nitrates. Citric acid is generally added during the preparation process. Citric acid is mainly used to complex and disperse metal ions, maintaining the molar ratio of metal Ba ions: metal Co ions: citric acid at 1:1:1.5~3. That is, Ba(NO3)2 and Co(NO3)2·6H2O are dissolved in an appropriate amount of deionized water and magnetically stirred to obtain a clear solution; a certain amount of citric acid is weighed and added, maintaining the molar ratio of metal Ba ions: metal Co ions: citric acid at 1:1:1.5~3. After being fully dissolved at 60-80℃, an appropriate amount of CeO2 carrier is added, controlling the mass percentage of BaCoO3 at 3~15%; when the perovskite A site and B site are respectively composed of components other than Ba ​​and Co, the preparation process of the impregnation solution is the same as above.

[0014] In the method of the present invention, the immersion time in step (3) is generally 1 to 5 hours.

[0015] In the method of the present invention, the drying conditions in step (3) are: drying temperature of 110~130℃ and drying time of 6-12 hours. The product is then kept at a constant temperature of 300-400℃ in a muffle furnace for 1~2 hours and then calcined. The calcination conditions are: calcination temperature of 700~800℃ and calcination time of 3~6 hours.

[0016] The application of the perovskite / cerium oxide catalyst of the present invention in the efficient decomposition and denitrification of NO in high-temperature flue gas, wherein the process conditions are as follows: NO concentration of 0.05~2 vol%, reaction temperature of 600~850℃, and reaction space velocity of 5000~50000 h⁻¹. -1 .

[0017] The beneficial effects of this invention are as follows: The perovskite / cerium oxide catalyst of this invention can directly decompose and denitrate NO, directly converting NO into N2 and O2 without the use of a reducing agent. It has outstanding advantages such as clean and environmentally friendly products, no secondary pollution, small equipment size, simple process, and good economic efficiency, making it the most ideal and environmentally friendly denitrification technology, especially suitable for denitrification of high-temperature flue gas generated by industrial furnaces and kilns. The preparation method of this invention can obtain spherical CeO2 supports with relatively uniform particle size and high molding rate, ultimately synthesizing a well-formed perovskite / cerium oxide spherical catalyst. The strong interaction between the active site and the support and the crystal facet regulation of the well-formed perovskite catalyst are key to achieving efficient direct decomposition of NO. The perovskite / CeO2 catalyst of this invention achieves high efficiency at a NO concentration of 8000 ppm, a spherical perovskite catalyst mass of 0.5 g, a total gas flow rate of 30 mL / min, and a high reaction space velocity of 5600 h⁻¹. -1 1 g·s / cm 3 The NO conversion rate is as high as 74.3% at 800℃. Attached Figure Description

[0018] Figure 1 The images are TEM images of the conventional random catalyst A and the spherical catalyst D of BaCoO3 / CeO2 in the embodiments of the present invention.

[0019] Figure 2 This is a diagram showing the direct decomposition and denitration of NO by the BaCoO3 / CeO2 series perovskite catalysts of this invention. Detailed Implementation

[0020] To facilitate understanding of the embodiments of the present invention, further explanations and descriptions will be provided below with reference to the accompanying drawings and specific embodiments. These embodiments do not constitute a limitation on the embodiments of the present invention.

[0021] Catalyst characterization experiments: 1) N2 physical adsorption-desorption analysis (N2-BET) The specific surface area and pore size distribution of the catalyst were calculated using N2 physical adsorption-desorption based on adsorption isotherms and the BET equation. After pretreating and degassing the powder sample (0.1 g) at 300 °C for 2 hours, the experiment was started using a Quantachrome Autosorb IQ instrument, and the physical adsorption-desorption experimental data of the sample were obtained at liquid nitrogen temperature (-196 °C).

[0022] 2) Transmission electron microscopy (TEM) analysis TEM is mainly used to observe the crystal geometry, particle size distribution, and surface morphology of samples at the molecular and atomic scales. The experimental instrument was a JEM-2200FS transmission electron microscope. The experimental procedure was as follows: the catalyst sample was first finely ground in an agate mortar, a small amount of powder was placed in anhydrous ethanol and ultrasonically dispersed, and after 0.5 h, the suspension was added dropwise to a copper grid supporting a carbon film. After natural drying, the sample was deposited on the copper grid, and finally the sample was observed using an electron microscope.

[0023] 3) Catalyst activity evaluation experiment The feed gas used in Comparative Examples 1, 2, and Example 1 below simulated high-temperature flue gas conditions in industrial furnaces. The NO concentration in the feed gas was 8000 ppm, the catalyst mass was 0.5 g, the particle size was 0.3~0.35 mm, the total gas flow rate was 30 mL / min, the reactor was a continuous flow fixed-bed reactor, the programmed heating rate was 10℃ / min, from room temperature to 850℃, and the temperature was held constant at the set temperature for 0.5 h. After stabilization, the products were detected, and the direct denitrification efficiency of NO for different perovskite catalysts was calculated and evaluated. The calculation formula is as follows: Comparative Example 1 A reactor was filled with pure BaCoO3 perovskite catalyst A. Catalyst A was prepared using a conventional method by dissolving Ba(NO3)2 and Co(NO3)2·6H2O in 200 mL of deionized water and magnetically stirring to obtain a clear solution. A certain amount of citric acid was added to maintain a molar ratio of Ba ions:Co ions:citric acid of 1:1:1.5. After thorough dissolution by stirring at 105 °C, most of the water was evaporated to obtain a gel. The gel was dried in a drying oven at 120 °C for 12 h, kept at 400 °C in a muffle furnace for 2 h, and then calcined at 700–800 °C for 4 h to obtain pure BaCoO3 perovskite catalyst A. Its direct NO decomposition performance was evaluated, and the results are shown in Example 4.

[0024] Comparative Example 2 The conventionally irregular morphology BaCoO3 / CeO2 catalyst B was prepared by impregnation. The irregularly morphological CeO2 was obtained by dissolving 5 g of cerium nitrate in 300 mL of deionized water and stirring thoroughly at 105 °C to obtain a gel. This gel was then dried in a drying oven at 120 °C for 12 h and calcined in a muffle furnace at 600 °C for 4 h. Ba(NO3)2 and Co(NO3)2·6H2O were dissolved in an appropriate amount of deionized water and magnetically stirred to obtain a clear solution. A certain amount of citric acid was weighed and added to maintain the molar ratio of metal Ba ions:metal Co ions:citric acid at 1:1:1.5. After complete dissolution at 80℃, an appropriate amount of irregularly shaped CeO2 support was added, controlling the mass percentage of BaCoO3 to be 5%. After thorough impregnation by stirring, the solution was dried at 110℃ for 6 h, kept at 400℃ in a muffle furnace for 1 h, and then calcined at 700℃ for 3-6 h to obtain the traditional irregularly shaped BaCoO3 / CeO2 catalyst B. Its direct NO decomposition performance was evaluated, and the results are shown in Example 4.

[0025] Comparative Example 3 Conventional spherical CeO2 supports were prepared using a method described in the literature (BL Zhang, Y. Huyan, JQ Wang, WB Wang, QY Zhang, HP Zhang. J. Am. Ceram. Soc. 2019, 102: 2218–2227.). First, 2 mmol of Ce(NO3)3·6H2O and 4 mmol of polyethylene (PVP) were dissolved in 40 mL of deionized water and stirred thoroughly. After complete dissolution, the solution was poured into a reaction vessel and placed in an oven to be heated to 200 °C for 2.5 h. After cooling to room temperature, the solid precipitate was filtered, washed three times with deionized water, and dried in a vacuum drying oven.

[0026] Conventional spherical catalyst C, consisting of BaCoO3 / CeO2, was prepared by impregnation. The preparation method was the same as the impregnation steps in Comparative Example 2. Its direct NO decomposition performance was evaluated, and the results are shown in Example 4.

[0027] Example 1 A method for preparing a well-formed spherical BaCoO3 / CeO2 catalyst D, the preparation method specifically includes the following steps: Regularly shaped spherical CeO2 supports were prepared by hydrothermal synthesis. First, 0.05 g of cerium nitrate was dissolved in 20 mL of ethanol solution and heated to 90 °C with stirring. Then, triethylenetetramine was added at a molar ratio of 2:1 to cerium nitrate and mixed thoroughly. Ammonia solution was added to adjust the pH to approximately 9. After complete dissolution, the solution was poured into a reaction vessel and heated to 120 °C in an oven for 6 h. The mixture was then allowed to stand for 12 h. The solid precipitate was filtered, washed with deionized water and ethanol until neutral, dried at 120 °C, and finally calcined at 500 °C for 4 h.

[0028] Catalyst D with well-defined morphology of BaCoO3 / CeO2 was prepared by impregnation method. Ba(NO3)2 and Co(NO3)2·6H2O were dissolved in 50 mL of deionized water and magnetically stirred to obtain a clear solution. A certain amount of citric acid was weighed and added to maintain the molar ratio of metal Ba ions: metal Co ions: citric acid at 1:1:1.5. After being fully dissolved at 80℃, an appropriate amount of spherical CeO2 support was added, controlling the mass percentage of BaCoO3 to be 5%. After stirring to achieve full impregnation, the solution was dried at 110℃ for 6 h, kept at 400℃ in a muffle furnace for 1 h, and then calcined at 700℃ for 3-6 h to obtain catalyst D. Its direct decomposition performance of NO was evaluated, and the results are shown in Example 4.

[0029] Example 2 A method for preparing a well-formed spherical BaMnO3 / CeO2 catalyst E, wherein the method for preparing the spherical CeO2 is the same as in Example 1, except that the molar ratio of triethylenetetramine to cerium nitrate is changed from 2:1 to 1:1.

[0030] The impregnation method is the same as in Example 1, except that Co(NO3)2·6H2O is replaced with Mn(NO3)2·4H2O to prepare catalyst E. Its direct NO decomposition performance was evaluated, and the results are shown in Example 4.

[0031] Example 3 A method for preparing a well-formed spherical LaCoO3 / CeO2 catalyst F, wherein the method for preparing the spherical CeO2 is the same as in Example 1, except that heating in the oven to 90°C is replaced with heating in the oven to 120°C.

[0032] The impregnation method is the same as in Example 1, except that Ba(NO3)2 is replaced with La(NO3)3·6H2O, and the mass percentage of BaCoO3 is controlled at 5% instead of 4%, to obtain catalyst F. Its direct NO decomposition performance was evaluated, and the results are shown in Example 4.

[0033] Example 4 Passing the N2-BET test and Figure 1The electron microscopy results, comparing the catalyst parameters of the comparative example and the examples, as well as the test results of the catalyst's performance in directly decomposing NO at 800℃, are shown in Table 1.

[0034] Table 1 Comparison of catalyst parameters and activities Example 5 The feed gas simulates the complex conditions of high-temperature flue gas in industrial furnaces. The NO concentration in the feed gas is 8000 ppm, the perovskite catalyst mass is 0.5 g, the particle size is 0.3~0.35 mm, the total gas flow rate is 30 mL / min, corresponding to a relatively high reaction volume hourly space velocity of 5600 h⁻¹. -1 (1 g·s / cm) 3 The reactor was a continuous flow fixed-bed reactor with a programmed heating rate of 10℃ / min, raising the temperature from room temperature to 850℃. The temperature was then held at the set point for 0.5 h to allow stabilization before product analysis. The direct decomposition and denitrification efficiency of NO using different catalysts was calculated and evaluated. The results are shown in [Figure number missing]. Figure 2 .

[0035] As attached Figure 1 As shown, the morphology of two typical catalysts, BaCoO3 / CeO2-irregular catalyst B and BaCoO3 / CeO2-spherical catalyst D, prepared in Comparative Example 2 and Example 1 respectively, was compared. The surface characteristics of the catalysts (interplanar spacing, exposed crystal faces) were analyzed by HRTEM. Statistical analysis of Figures (a) BaCoO3 / CeO2-irregular and (b) BaCoO3 / CeO2-spherical catalysts shows that BaCoO3 / CeO2-irregular catalyst has the smallest average particle size, around 20~30 nm; while BaCoO3 / CeO2-spherical catalyst D has an average particle size of around 120~180 nm, with more uniform particle size and higher molding rate. Meanwhile, the interplanar spacing of each catalyst was measured using Digital Micrograph. It was found that perovskite mainly exposed {110}, {211}, and {102} crystal planes; while cerium oxides of different morphologies exposed different crystal planes. In BaCoO3 / CeO2-irregular catalyst B, the irregular CeO2 mainly exposed the {111} crystal plane, while BaCoO3 / CeO2-spherical catalyst D mainly exposed the {220} crystal plane. It can be seen that cerium oxide supports of different morphologies exposed different crystal planes. The low-energy-barrier {220} crystal plane is more stable and easier to form an effective reactive interface with the active sites, which is beneficial to improving the dispersion of active sites and enhancing the strong interaction between active sites and the support.

[0036] As shown in Table 1, perovskite catalysts that have undergone high-temperature calcination generally exhibit relatively low specific surface areas, and pure BaCoO3 catalyst A also follows this pattern, with a low specific surface area of ​​1.25 m². 2 / g. The addition of CeO2 support, especially well-ordered spherical CeO2, significantly increases the specific surface area of ​​the catalyst. It is evident that compared to the specific surface area of ​​the current traditional randomized BaCoO3 / CeO2 catalyst B (16.47 m²), this significantly increases the catalyst's specific surface area. 2 / g) and conventional spherical BaCoO3 / CeO2 catalyst C (26.68 m 2 The BaCoO3 / CeO2-spherical catalyst D synthesized in this invention exhibits a large specific surface area of ​​30.63 m² / g. 2 / g can expose more active sites, which is beneficial to improve catalyst activity.

[0037] As attached Figure 2 As shown, comparative BaCoO3 catalyst A, random BaCoO3 / CeO2 catalyst B, and the present invention's BaCoO3 / CeO2-spherical catalyst D were selected. The NO concentration was 8000 ppm / Ar, the catalyst mass was 0.5 g, the total gas flow rate was 30 mL / min, and the higher space velocity was 1 g·s / cm². 3 The performance of direct NO decomposition at different temperatures was evaluated. At 800℃, the order of catalyst activity was: BaCoO3 / CeO2-spherical catalyst D (74.3%) > BaCoO3 / CeO2-irregular catalyst B (57.7%) > BaCoO3 catalyst A (8.8%). This shows that compared to the conventional BaCoO3 / CeO2-irregular catalyst B, the conversion rate of NO to N2 on BaCoO3 / CeO2-spherical catalyst D was increased by nearly 17%, and the addition of regularly shaped CeO2 (spherical) catalysts greatly improved the catalyst activity. (See attached...) Figure 1 As shown in Table 1, the regularly morphological BaCoO3-CeO2-spherical catalyst D has a larger specific surface area and average particle size. Furthermore, a stronger reaction interface between the BaCoO3 active sites and CeO2 is easily formed on the {220} crystal facet of the CeO2 support. The increased perimeter of the interface further improves the dispersion of active sites and the reaction contact time with the reactant NO, thereby promoting the effective improvement of catalytic activity. This is due to the strong interaction and crystal facet regulation between the reactive active sites and the regularly morphological support CeO2 uniquely generated by the regularly morphological catalyst designed in this patent.

Claims

1. A perovskite / cerium oxide type catalyst, characterized in that: The catalyst comprises an active component, perovskite ABO3, and a support, cerium oxide CeO2. The A-site is one or more of Ba, La, and Sr, and the B-site is one or more of Cu, Mn, Ni, Co, Fe, K, and Mg. The molar ratio of A to B is 1-5:

1. The active component, perovskite ABO3, accounts for 3wt%-10wt% of the total catalyst mass. The catalyst is spherical, with 60%-90% exposure of the {220} crystal face, an average particle size of 120-180 nm, and a specific surface area of ​​20-35 m². 2 / g.

2. The catalyst according to claim 1, characterized in that: The A position is Ba, and the B position is Co.

3. A method for preparing the perovskite / cerium oxide type catalyst according to claim 1 or 2, characterized in that... The following are included: (1) Dissolve cerium nitrate in an ethanol solution and heat it to 50-95℃, then add triethylenetetramine and mix evenly; (2) Add an ammonia solution to adjust the pH value to 8-11, carry out a hydrothermal reaction, and then age it. After aging, filter, wash, dry and calcine the solid precipitate to obtain a spherical cerium oxide support; (3) Prepare a perovskite active component impregnation solution, then impregnate the spherical cerium oxide support with the impregnation solution, dry it, keep it at a constant temperature for a period of time, and calcine it to obtain a perovskite / cerium oxide type catalyst.

4. The method according to claim 3, characterized in that: The molar ratio of triethylenetetramine to cerium nitrate in step (1) is 1~3:

1.

5. The method according to claim 3, characterized in that: The hydrothermal reaction conditions described in step (2) are: time of 2-8 hours, temperature of 80-200℃, and the reaction is carried out in a reaction vessel.

6. The method according to claim 3, characterized in that: The aging conditions described in step (2) are: aging time of 10-24 hours and aging temperature of 20-30℃.

7. The method according to claim 3, characterized in that: The drying conditions described in step (2) are: drying temperature of 80~140℃ and drying time of 6~12 hours; the calcination conditions described in step (2) are: calcination temperature of 400~600℃ and calcination time of 2~6 hours.

8. The method according to claim 3, characterized in that: The soaking time in step (3) is 1 to 5 hours.

9. The method according to claim 3, characterized in that: The drying conditions described in step (3) are: drying temperature of 110~130℃ and drying time of 6-12 hours.

10. The method according to claim 3, characterized in that: The constant temperature process described in step (3) is: 300-400℃ for 1~2 hours.

11. The method according to claim 3, characterized in that: The roasting conditions are as follows: roasting temperature is 700~800℃, and roasting time is 3~6 hours.

12. The application of the perovskite / cerium oxide type catalyst according to claim 1 or 2 in the efficient decomposition and denitrification of NO in high-temperature flue gas, wherein the process conditions are: NO concentration of 0.05~2 vol%, reaction temperature of 600~850℃, and reaction space velocity of 5000~50000 h⁻¹. -1 .

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