A VOCs catalyst, preparation method and application

Abstract

A perovskite-type catalyst and a preparation method thereof are provided. The perovskite-type catalyst comprises a perovskite-type active component with the general formula A x B 1‑x Mn y Ti 1‑y O3 and a sepiolite component. The catalyst preparation method includes: treating sepiolite with an inorganic acid modified solution; mixing sepiolite and citric acid; adding soluble metal salts of A and B; adding Mn / TiO2 sol; adding an ethylene glycol aqueous solution, and heating and evaporating to obtain a gel; drying, heating, and burning under anaerobic conditions the gel, and then shaping and roasting the combustion ash to obtain the catalyst. The preparation process of this catalyst is simple, easy to operate, suitable for large-scale industrial application, overcomes the disadvantage of poor dispersion of perovskite powder prepared by the self-combustion method, improves the high-temperature sintering resistance of the catalyst, and has excellent thermal stability.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy utilization and environmental protection, and particularly relates to a perovskite-type VOCs catalyst, a preparation method and an application thereof. Background Art

[0002] Volatile organic compounds (VOCs) generally refer to organic compounds with a saturated vapor pressure greater than 70 Pa at normal temperature and a boiling point below 260 °C under normal pressure. They can participate in the formation of ozone and secondary aerosols in the atmospheric environment and are severely polluting chemical substances.

[0003] Currently, methods for treating volatile organic waste gases include adsorption and absorption methods, biodegradation treatment methods, UV ultraviolet photolysis-plasma methods, direct combustion and catalytic combustion methods, etc. Among them, catalytic combustion for treating VOCs is widely adopted due to its high purification rate, low ignition temperature, energy saving, simple process, no secondary pollution and other characteristics.

[0004] The research on VOCs catalytic combustion catalysts mainly focuses on noble metal catalysts (Pt, Pd and Au) and non-noble metal oxide catalysts. Among them, Pd catalysts are the most mature and widely used combustion catalysts in industry, but they are expensive. Non-noble metal catalysts have poor low-temperature activity, but they are rich in resources, inexpensive and have the prospect of large-scale application.

[0005] Among non-noble metal catalytic combustion catalysts, perovskite-type composite metal oxide (structural general formula ABO3) catalysts are one of the most promising catalytic combustion catalysts.

[0006] CN105289602 A discloses a cerium-zirconium composite oxide-supported perovskite-type catalyst with sulfur resistance, that is, first load the perovskite onto the Ce 1-y Zr y O2 composite oxide, and then load the noble metal promoter thereon. This catalyst has high catalyst reaction activity during the catalytic combustion of VOCs and has strong sulfur poisoning resistance.

[0007] CN109999795 A discloses an attapulgite clay-supported LaMnO3 catalyst (abbreviated as LaMnO3 / ATP) for degrading volatile organic pollutants.

[0008] CN1015283443 A discloses a method for optimizing the catalytic activity of a perovskite-based catalyst, that is, subjecting the fully synthesized perovskite structure to high-energy ball milling to obtain a larger specific surface area, so as to achieve the purpose of improving the catalyst activity. However, the method of only increasing the specific surface area to improve the catalytic activity has certain limitations.

[0009] Perovskite-type metal oxide catalysts have good stability, but there are still problems such as low specific surface area and easy sintering at high temperatures, which limit the application of perovskite-type catalysts to a certain extent.

[0010] Therefore, there is an urgent need for a new VOCs catalyst and its preparation method to solve the above technical problems. Summary of the Invention

[0011] The purpose of the present invention is to provide a perovskite-type catalyst with a high specific surface area and its preparation method. The catalyst has excellent thermal stability when applied to VOCs catalytic combustion, and is low in cost and simple to prepare.

[0012] In order to overcome the deficiencies of the prior art, the present invention provides a perovskite-type catalyst with a high specific surface area and excellent thermal stability. Based on the weight percentage of the catalyst, the catalyst composition includes 40-50% of perovskite-type active components, and the rest is sepiolite component;

[0013] Among them, the general formula of the perovskite-type active component is A x B 1-x Mn y Ti 1-y O3, where x = 0.1-0.4, y = 0.5-0.8, and A is at least one of La and Ce, and B is at least one of Mg and Ca.

[0014] The pore volume of the catalyst is 0.45 mL / g - 0.55 mL / g, 90% of the pore diameter is 25 nm - 45 nm, and the specific surface area is 100 m 2 / g - 130 m 2 / g.

[0015] The appearance of the catalyst can be strip-shaped, clover-shaped, four-leaf clover-shaped or spherical, etc.

[0016] The bulk density of the catalyst is 0.75 - 0.90 Kg / L, and the side compression strength of the catalyst is 100 - 120 N / cm.

[0017] The present invention also provides a preparation method of the above perovskite-type catalyst, including:

[0018] (1) Prepare an inorganic acid modified solution; then, according to a solid-liquid weight ratio of 1:15 - 30, add sepiolite and the inorganic acid modified solution to a reactor, heat to 50 - 100 °C, stir for a period of time, after stirring is completed, filter and wash with water until neutral, and obtain modified sepiolite after drying and calcination;

[0019] (2) Take a certain amount of the modified sepiolite obtained in step (1) and citric acid, pour them into water, and mix evenly to obtain a first mixture;

[0020] (3) Prepare aqueous solutions of soluble metal salts of A and B respectively according to the molar ratio of metal elements required for the perovskite-type active component, and drop them into the first mixture obtained in step (2) respectively, and stir evenly to obtain a second mixture;

[0021] (4) Prepare a Mn / TiO2 sol, and then drop the prepared Mn / TiO2 sol into the second mixture obtained in step (3), and stir evenly to obtain a third mixture;

[0022] (5) Add a certain amount of ethylene glycol aqueous solution to the third mixture obtained in step (4) and stir evenly; heat to a certain temperature to evaporate the water, and gradually turn it into a gel;

[0023] (6) Dry the gel obtained in step (5) at 80-150 °C, then transfer it to an electric furnace and heat it until spontaneous combustion occurs and then keep it at a constant temperature; crush the combustion ash, add a binder and an extrusion aid, extrude it into a shape, air-dry it, and calcine it to obtain the catalyst.

[0024] Among them, in the step (1), the water is distilled water, and the stirring time is 8-12 h.

[0025] Among them, in the step (1), the sepiolite selected is α-type sepiolite, the color is white or light gray, avoiding light red, light yellow or brown, etc. Preferably, the sepiolite is pure white sepiolite or grayish-white sepiolite. The mass percentage composition of the pure white sepiolite is: SiO2 66%-68%, MgO 30%-32%, Fe x O y <0.2%, and the balance is Al2O3 and CaO; the mass percentage composition of the grayish-white sepiolite is: SiO2 65%-67%, MgO 30%-32%, Fe x O y <1.0%, and the balance is Al2O3 and CaO.

[0026] Among them, in the step (1), the calcination temperature is 350-400 °C, and the calcination time is 4-8 h.

[0027] Among them, in the step (1), the inorganic acid is one of nitric acid, hydrochloric acid or sulfuric acid, preferably nitric acid; the concentration of the inorganic acid is 0.2-0.4 mol / L.

[0028] Among them, in the step (2), the water is deionized water.

[0029] Among them, in the step (3), the soluble metal salt of A is at least one of lanthanum nitrate and cerium nitrate; the soluble metal salt of B is at least one of magnesium nitrate and calcium nitrate.

[0030] Among them, in the step (2), the ratio of the molar amount of citric acid to the sum of the molar amounts of metal ions in steps (3) and (4) is 1:2 to 4.

[0031] Among them, in the step (4), the preparation method of the Mn / TiO₂ sol includes:

[0032] Measure a certain amount of tetrabutyl titanate, absolute ethanol, and polyethylene glycol (PEG600) respectively into a reaction kettle and stir strongly. Drop glacial acetic acid into the mixed solution to control its pH value to be 4 to 5;

[0033] Then weigh a certain amount of manganese acetate according to the molar ratio of metal elements required for the perovskite-type active component, and dissolve it in deionized water to obtain a Mn(Ac)₂ solution;

[0034] Slowly add the Mn(Ac)₂ solution into the reaction kettle. After completion, continue to stir for a period of time to obtain the Mn / TiO₂ sol.

[0035] Among them, in the step (5), the mass concentration of the ethylene glycol aqueous solution is greater than 60%, and the addition amount of the ethylene glycol aqueous solution is 10 to 15% of the total mass of the perovskite-type active component ABO₃. Ethylene glycol acts as a combustion aid in the preparation process.

[0036] Among them, in the step (6), drying is carried out at 80 - 150 °C.

[0037] Among them, in the step (6), the temperature of the constant temperature is 200 - 250 °C. After the material is ignited, air with an oxygen content of 15 - 18% (v / v) needs to be introduced to control the combustion speed.

[0038] Among them, in the step (6), the binder is one or more of sodium silicate, citric acid, oxalic acid, and nitric acid, and the addition amount of the binder is 1 - 6% (m / m) of the combustion ash; preferably, the binder is at least one of sodium silicate and citric acid, and its addition amount is 2 - 4% (m / m) of the combustion ash.

[0039] Among them, in the step (6), the extrusion aid is sesbania powder and starch, and the addition amount is 1 - 6% (m / m) of the combustion ash; preferably, the extrusion aid is sesbania powder, and the addition amount is 3 - 4% (m / m) of the combustion ash.

[0040] Among them, in the step (6), the calcination temperature is 500 - 1000 °C, and the calcination time is 4 - 8 h; preferably, the calcination temperature is 700 - 780 °C, and the calcination time is 5 - 6 h. The level of the calcination temperature affects the formation of the perovskite-type active component.

[0041] The present invention also provides an application of the perovskite-type catalyst in catalytic combustion for treating volatile organic compounds.

[0042] The present invention has the following beneficial technical effects:

[0043] (1) The present invention uses acid-modified sepiolite as a carrier, and loads the active component sol onto the modified sepiolite by the beating method. After the active component gel undergoes anaerobic self-combustion and then is calcined, a perovskite structure is formed, enabling the active components to be uniformly dispersed on the sepiolite carrier, and a perovskite-type VOCs catalytic combustion catalyst is prepared.

[0044] (2) Sepiolite (Mg8[Si2O 30 (OH)4·12H2O) is a magnesium-rich silicate clay mineral, belonging to the chain-layered hydrous magnesium aluminum silicate or magnesium silicate mineral of the monoclinic system or orthorhombic system of S. It has a huge specific surface area and can adsorb various reactants and active components of the catalyst. Through acid modification, H + partially replaces the magnesium ions in the sepiolite skeleton, causing partial deconstruction of the magnesium-oxygen octahedral sheets sandwiched by the silicon-oxygen tetrahedral sheets, and the internal channels are connected and expanded, significantly increasing the specific surface area of the sepiolite carrier. The pore size of sepiolite matches the sizes of reactant molecules and catalyst components, and the sepiolite carrier can exhibit good activity and high heat resistance, thus obtaining a catalyst carrier with a high specific surface area, which is beneficial to the adsorption of VOCs during the reaction process.

[0045] (3) During the preparation process, the gel solid naturally makes the material fluffy, which is beneficial to the dispersion of the active components, increases the exposure amount of active sites, and significantly increases the catalytic activity.

[0046] (4) The method of the present invention can not only load a large amount of active components but also easily regulate the composition of the active substances of the catalyst. The appropriate composition improves the high-temperature sintering resistance of the active components, making the catalyst have excellent thermal stability.

[0047] (5) The method of the present invention can increase the dispersion degree of the catalyst and improve its thermal stability by introducing a structural assistant with a thermal stabilizing effect and loading the perovskite-type metal oxide catalyst on an appropriate high-specific-surface-area carrier.

[0048] (6) The preparation process of the present invention is simple, easy to operate, and suitable for large-scale industrial applications.

[0049] (7) The catalyst prepared by the method of the present invention has a high perovskite component purity, small particle size, overcomes the disadvantage of poor dispersion of the perovskite powder prepared by the self-combustion method, improves the high-temperature sintering resistance of the catalyst, and has excellent thermal stability. Detailed implementation manners

[0050] In view of the problems existing in the existing titanium ore type catalytic combustion catalysts, such as low specific surface area and easy sintering at high temperature, the present invention proposes a perovskite type catalytic combustion catalyst with high specific surface area, a preparation method and an application thereof.

[0051] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the following further details the present invention in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0052] Example 1

[0053] 1) Prepare a 0.2 mol / L nitric acid solution, add 122.4 g of sepiolite powder according to the solid-liquid weight ratio of 1:15, and calcine at 400 °C for 4 h after stirring, washing and drying to obtain modified sepiolite;

[0054] 2) Add the modified sepiolite and 134.4 g of citric acid to 500 mL of deionized water and mix well by stirring.

[0055] 3) Prepare 200 mL of a 0.5 mol / L lanthanum nitrate solution and 900 mL of a 1.0 mol / L magnesium nitrate solution respectively, and stir and add the solutions to the mixture in step 2).

[0056] 4) Prepare an Mn / TiO2 sol according to the molar ratio of Mn:Ti = 1:1, take 416 g of the sol and slowly add it to the mixture in step 3), and stir evenly.

[0057] 5) Add 25 mL of ethylene glycol solution to the mixture in step 4), stir evenly, and then heat to evaporate the water until a gel is formed.

[0058] 6) Dry the gel obtained in step 5) at 150 °C, then transfer it to an electric furnace, heat it to 250 °C to cause spontaneous combustion and then keep it at a constant temperature, and control the combustion rate by introducing air with an oxygen content of 18% (v / v). After crushing the combustion ash, add 5 g of citric acid and 7.5 g of sesbania powder, extrude into shape, air dry, and calcine at 750 °C for 5 h to obtain the catalyst.

[0059] In the catalyst prepared by the above steps, the content of the perovskite active component is 50%, and the active component composition is La 0.1 Mg 0.9 Mn 0.5 Ti 0.5 O3, denoted as cat-1.

[0060] Examples 2-8

[0061] According to the preparation method of Example 1, adjust the proportion of each component according to the parameter range in the specification, and the prepared catalysts are denoted as cat-2 to cat-8 respectively, as shown in Table 1.

[0062] Comparative Example 1 - Ti was introduced in the form of metatitanic acid in step (2), rather than in the form of Mn / TiO₂ sol in step (4) as in Example 1.

[0063] 1) Prepare a 0.2 mol / L nitric acid solution, add 122.4 g of sepiolite powder according to the solid-liquid weight ratio of 1:15, and after stirring, washing, and drying, calcine at 400 °C for 4 h to obtain modified sepiolite.

[0064] 2) Add the modified sepiolite, 134.4 g of citric acid, and 48.9 g of metatitanic acid to 500 mL of deionized water and mix well by stirring.

[0065] 3) Prepare 200 mL of a 0.5 mol / L lanthanum nitrate solution and 900 mL of a 1.0 mol / L magnesium nitrate solution respectively, and stir and add the solutions to the mixture in step 2).

[0066] 4) Prepare 500 mL of a 1.0 mol / L manganese nitrate solution, slowly add it to the mixture in step 3), and stir well.

[0067] 5) Add 25 mL of ethylene glycol solution to the mixture in step 4), stir well, and then heat to evaporate the water until a gel is formed.

[0068] 6) Dry the gel obtained in step 5) at 150 °C, then transfer it to an electric furnace, heat it to 250 °C to cause spontaneous combustion and then keep it at a constant temperature, and introduce air with an oxygen content of 15% (v / v) to control the combustion rate. After crushing the combustion ash, add 5 g of citric acid and 7.5 g of sesbania powder, extrude into shape, air dry, and calcine at 750 °C for 5 h to obtain the catalyst.

[0069] In the catalyst prepared by the above steps, the content of the perovskite active component is 50%, and the active component composition is La 0.1 Mg 0.9 Mn 0.5 Ti 0.5 O₃, denoted as cat-9.

[0070] Comparative Example 2 - The modified sepiolite was not treated with citric acid.

[0071] 1) Prepare a 0.2 mol / L nitric acid solution, add 122.4 g of sepiolite powder according to the solid-liquid weight ratio of 1:15, and after stirring, washing, and drying, calcine at 400 °C for 4 h to obtain modified sepiolite.

[0072] 2) Prepare 200 mL of a 0.5 mol / L lanthanum nitrate solution and 900 mL of a 1.0 mol / L magnesium nitrate solution respectively, and mix the two to obtain a mixed solution.

[0073] 3) Prepare the Mn / TiO₂ sol according to the molar ratio of Mn:Ti = 1:1, and slowly add 416 g of the sol to the mixture in step 2), and stir evenly.

[0074] 4) Add 25 mL of ethylene glycol solution to the mixture in step 3), stir evenly, and then heat to evaporate the water until a gel is formed.

[0075] 5) Dry the gel obtained in step 4) at 150 °C, then transfer it to an electric furnace, heat it to 250 °C to cause spontaneous combustion, and then keep it at a constant temperature. Pass air with an oxygen content of 16% (v / v) to control the combustion rate. After crushing the combustion ash, add 5 g of citric acid, 7.5 g of sesbania powder, and 122.4 g of the modified sepiolite in step 1), mix evenly, extrude into shape, air dry, and calcine at 750 °C for 5 h to obtain the catalyst.

[0076] In the catalyst prepared by the above steps, the content of the perovskite active component is 50%, and the active component composition is La 0.1 Mg 0.9 Mn 0.5 Ti 0.5 O₃, denoted as comparative cat-10.

[0077] Comparative Example 3 - Without adding ethylene glycol solution and evaporating to form a gel, without performing oxygen-deficient spontaneous combustion

[0078] 1) Prepare a 0.2 mol / L nitric acid solution, add 122.4 g of sepiolite powder according to the solid-liquid weight ratio of 1:15, and after stirring, washing, and drying, calcine at 400 °C for 4 h to obtain modified sepiolite.

[0079] 2) Add the modified sepiolite and 134.4 g of citric acid to 500 mL of deionized water, and mix and stir evenly.

[0080] 3) Prepare 200 mL of 0.5 mol / L lanthanum nitrate solution and 900 mL of 1.0 mol / L magnesium nitrate solution respectively, and stir and add the solutions to the mixture in step 2).

[0081] 4) Prepare the Mn / TiO₂ sol according to the molar ratio of Mn:Ti = 1:1, and slowly add 416 g of the sol to the mixture in step 3), and stir evenly.

[0082] 5) Dry the mixture obtained in step 4) at 150 °C, crush the dried material, add 5 g of citric acid and 7.5 g of sesbania powder, extrude into shape, air dry, and calcine at 750 °C for 5 h to obtain the catalyst.

[0083] In the catalyst prepared by the above steps, the content of the perovskite active component is 50%, and the active component composition is La 0.1 Mg 0.9 Mn 0.5 Ti0.5 O3, designated as Comparative Example cat-11.

[0084] Comparative Example 4 - Does not spontaneously combust under anaerobic conditions

[0085] 1) Prepare a 0.2 mol / L nitric acid solution, add 122.4 g of sepiolite powder according to a solid-liquid weight ratio of 1:15, and calcine at 400 °C for 4 h after stirring, washing, and drying to obtain modified sepiolite.

[0086] 2) Add the modified sepiolite and 134.4 g of citric acid to 500 mL of deionized water and mix well by stirring.

[0087] 3) Prepare 200 mL of a 0.5 mol / L lanthanum nitrate solution and 900 mL of a 1.0 mol / L magnesium nitrate solution respectively, and stir and add the solutions to the mixture in step 2).

[0088] 4) Prepare an Mn / TiO2 sol according to a molar ratio of Mn:Ti = 1:1, take 416 g of the sol and slowly add it to the mixture in step 3), and stir evenly.

[0089] 5) Add 25 mL of ethylene glycol solution to the mixture in step 4), stir evenly, and then heat to evaporate the water until a gel is formed.

[0090] 6) Dry the gel obtained in step 5) at 150 °C, then transfer it to an electric furnace and heat to 250 °C to initiate spontaneous combustion. After crushing the combustion ash, add 5 g of citric acid and 7.5 g of sesbania powder, extrude into shape, air dry, and calcine at 750 °C for 5 h to obtain the catalyst.

[0091] In the catalyst prepared through the above steps, the content of the perovskite active component is 50%, and the active component composition is La 0.1 Mg 0.9 Mn 0.5 Ti 0.5 O3, designated as Comparative Example cat-12.

[0092] The catalysts prepared in Comparative Examples 1 to 4 are listed in Table 1.

[0093] Table 1 Catalysts Prepared in Examples and Comparative Examples

[0094] Composition Number Example 1 <![CDATA[La 0.1 Mg 0.9 Mn 0.5 Ti 0.5 O3]]> cat-1 Example 2 <![CDATA[La 0.4 Mg 0.6 Mn 0.5 Ti 0.5 O3]]> cat-2 Example 3 <![CDATA[La 0.4 Mg 0.6 Mn 0.8 Ti 0.2 O3]]> cat-3 Example 4 <![CDATA[La 0.1 Mg 0.9 Mn 0.8 Ti 0.2 O3]]> cat-4 Example 5 <![CDATA[Ce 0.4 Ca 0.6 Mn 0.5 Ti 0.5 O3]]> cat-5 Example 6 <![CDATA[Ce 0.1 Ca 0.9 Mn 0.5 Ti 0.5 O3]]> cat-6 Example 7 <![CDATA[Ce 0.4 Ca 0.6 Mn 0.8 Ti 0.2 O3]]> cat-7 Example 8 <![CDATA[Ce 0.1 Ca 0.9 Mn 0.8 Ti 0.2 O3]]> cat-8 Comparative Example 1 <![CDATA[La 0.1 Mg 0.9 Mn 0.5 Ti 0.5 O3]]> cat-9 Comparative Example 2 <![CDATA[La 0.1 Mg 0.9 Mn 0.5 Ti 0.5 O3]]> cat-10 Comparative Example 3 <![CDATA[La 0.1 Mg 0.9 Mn 0.5 Ti 0.5 O3]]> cat-11 Comparative Example 4 <![CDATA[La 0.1 Mg 0.9 Mn 0.5 Ti 0.5 O3]]> cat-12

[0095] Performance test:

[0096] The perovskite catalysts prepared in Examples 1-8 and Comparative Examples 1-4 were subjected to an activity test, and the test was carried out in a fixed-bed reactor. The whole device consists of a gas generation system and a catalytic combustion system. The concentration of the feed gas was controlled by adjusting the air flow rate and the feed gas flow rate. The inlet and outlet concentrations were detected every 10 °C from 200 to 400 °C, and on-line analysis and detection were carried out using a GC-14C gas chromatograph (FID, dual columns).

[0097] The specific activity evaluation conditions were as follows:

[0098] Catalyst particle size: 40-60 mesh;

[0099] Catalyst loading: 10 mL;

[0100] Composition of the feed gas: toluene 4000 mg / m 3 , and the rest was air;

[0101] Space velocity: 25000 h -1

[0102] The specific catalyst stability evaluation conditions were as follows:

[0103] Catalyst particle size: 40-60 mesh;

[0104] Composition of the feed gas: toluene 4000 mg / m 3 , and the rest was air;

[0105] Space velocity: 25000 h -1 ;

[0106] Evaluation temperature 400 °C

[0107] The catalyst evaluation data are listed in Table 2 (in the table, T 90 , T 99 are the reaction temperatures when the conversion rates reach 90% and 99% respectively, and the conversion rate is the data at 400 °C).

[0108] Table 2 Catalyst activity evaluation data

[0109]

[0110] It can be seen from the data in Table 2 that the catalyst of the present invention has good conversion rate for VOCs.

[0111] The catalyst cat-1 of Example 1 and the catalysts cat-9, cat-10, cat-11, cat-12 of Comparative Examples 1-4 were operated under the stability evaluation conditions for 200 h, and the catalyst activity was tested to be stable. Samples were taken for analysis every 50 h, and the evaluation data are listed in Table 3.

[0112] Table 3 Catalyst activity stability evaluation data

[0113]

[0114] As can be seen from Table 3, although the catalyst cat-1 has the same active components and the same content as the comparative catalysts cat-9, cat-10, cat-11, and cat-12, the difference in the preparation process results in a large difference in their activity stability. The catalyst prepared by the process of the present invention has better activity stability.

[0115] Obviously, the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A preparation method of a perovskite-type catalyst, Based on the weight percentage of the catalyst, the perovskite-type catalyst comprises 40 - 50% of a perovskite-type active component, and the rest is sepiolite component; Among them, The general formula of the perovskite-type active component is A x B 1-x Mn y Ti 1-y O3, where x = 0.1 - 0.4, y = 0.5 - 0.8, and A is at least one of La and Ce, and B is at least one of Mg and Ca; The preparation method of the perovskite-type catalyst comprises: (1) Prepare an inorganic acid modified solution; then, according to a solid-liquid weight ratio of 1:15 - 30, add sepiolite and the inorganic acid modified solution into a reactor, heat to 50 - 100 °C, stir for a period of time, after stirring is completed, carry out suction filtration and washing with water until neutral, dry and calcine to obtain modified sepiolite; wherein, in the step (1), the inorganic acid is one of nitric acid, hydrochloric acid or sulfuric acid; (2) Take a certain amount of the modified sepiolite obtained in the step (1) and citric acid, pour them into water, and mix evenly to obtain a first mixture; (3) According to the molar ratio of metal elements required for the perovskite-type active component, prepare aqueous solutions of soluble metal salts of A and B respectively, and drop them into the first mixture obtained in the step (2) respectively, stir evenly to obtain a second mixture; (4) Prepare Mn / TiO₂ sol, and then drop the prepared Mn / TiO₂ sol into the second mixture obtained in the step (3), stir evenly to obtain a third mixture; (5) Add a certain amount of ethylene glycol aqueous solution to the third mixture obtained in the step (4), stir evenly; raise the temperature to a certain temperature to evaporate water, and gradually turn it into a gel; (6) Dry the gel obtained in the step (5), then heat it until it ignites spontaneously and keep it at a constant temperature; wherein after ignition, introduce air with an oxygen content of 15 - 18% (v / v); then crush the combustion ash, add a binder and an extrusion aid, extrude into a shape, air dry, and calcine to obtain the catalyst.

2. The preparation method of the perovskite-type catalyst according to claim 1, wherein, In the step (1), the sepiolite selected is α-type sepiolite.

3. The preparation method of the perovskite-type catalyst according to claim 1, wherein, In the step (4), the preparation method of the Mn / TiO₂ sol comprises: Measure a certain amount of tetrabutyl titanate, absolute ethanol and polyethylene glycol respectively in a reaction kettle, stir strongly, and drop glacial acetic acid into the mixed solution to control its pH value to be 4 - 5; Then weigh a certain amount of manganese acetate according to the molar ratio of metal elements required for the perovskite-type active component, dissolve it in deionized water to obtain a Mn(Ac)₂ solution; Slowly add the Mn(Ac)₂ solution into the reaction kettle, and continue to stir for a period of time after completion to obtain the Mn / TiO₂ sol.

4. The preparation method of the perovskite-type catalyst according to claim 1, wherein, In the step (3), the soluble metal salt of A is at least one of lanthanum nitrate and cerium nitrate; the soluble metal salt of B is at least one of magnesium nitrate and calcium nitrate.

5. The preparation method of the perovskite-type catalyst according to claim 1, wherein, The ratio of the molar number of citric acid in the step (2) to the sum of the molar numbers of metal ions in the steps (3) and (4) is 1:2 - 4.

6. The preparation method of the perovskite-type catalyst according to claim 1, wherein, In the step (6), the temperature of the constant temperature is 200 - 250 °C.

7. The preparation method of the perovskite-type catalyst according to claim 1, wherein, In the step (6), the calcination temperature is 500 - 1000 °C, and the calcination time is 4 - 8 h.

8. A perovskite-type catalyst prepared by the preparation method of the perovskite-type catalyst according to any one of claims 1 - 7.

9. The perovskite-type catalyst according to claim 8, wherein, The pore volume of the catalyst is 0.45 mL / g - 0.55 mL / g, and the specific surface area is 100 m 2 / g - 130 m 2 / g.

10. Application of the perovskite-type catalyst according to claim 8 or 9 in catalytic combustion for treating volatile organic compounds.

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