Preparation method and application of manganese-based core-shell structure denitration catalyst for combined removal of CO and VOCs

Abstract

This invention discloses a method for preparing a manganese-based core-shell structured denitrification catalyst for the combined removal of CO and VOCs, and its application, belonging to the field of catalyst technology. The method employs a homogeneous deposition process to introduce iron, copper, silicon, and phosphorus elements onto the surface of a manganese dioxide core, forming corresponding oxide layers to obtain the manganese-based core-shell structured denitrification catalyst. This method is simple, and the resulting catalyst exhibits sulfur resistance at lower temperatures, strong oxidation performance for carbon monoxide and volatile organic compounds, and high selectivity for nitrogen in denitrification at high temperatures. This invention shows broad promise for applications in the combined removal of multiple pollutants.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, and in particular to a method for preparing and applying a manganese-based core-shell structured denitrification catalyst for the combined removal of CO and VOCs. Background Technology

[0002] The combined removal of multiple pollutants using catalysts is a current trend. Low-temperature denitrification catalysts based on manganese have been extensively studied and explored.

[0003] Chinese patent CN109529816A discloses a core-shell MnO2@TiO2 catalyst, its preparation method, and its application. The prepared core-shell titanium dioxide-coated manganese dioxide catalyst exhibits high catalytic activity, non-toxicity, and good stability in selective catalytic reduction denitrification technology. The core-shell structure protects the active components from exposure to flue gas containing sulfur dioxide and water, improving catalyst stability and resistance to water and sulfur dioxide poisoning, and increasing the catalyst's recyclability.

[0004] Chinese patent CN110280264A discloses a denitrification catalyst, its preparation method, and its application. This denitrification catalyst comprises manganese tetroxide (Mn3O4) doped with copper compounds. The denitrification catalyst of this invention exhibits excellent denitrification efficiency at low temperatures, is inexpensive, environmentally friendly, and has no significant toxicity. Furthermore, it has strong sulfur resistance and reduces irreversible deactivation during use.

[0005] The catalysts involved in the above-mentioned existing technologies mainly focus on optimizing sulfur resistance, but their applicable operating temperature range is still relatively narrow. In addition, the function of the sulfur-resistant layer is singular, making it difficult to simultaneously meet the needs of removing multiple pollutants. Currently, the sulfur resistance characteristics of manganese-based low-temperature catalysts at lower temperatures, as well as their oxidation performance of carbon monoxide (CO) and volatile organic compounds (VOCs), still need to be improved, and they also suffer from the defect of low nitrogen selectivity in denitrification at high temperatures. Summary of the Invention

[0006] In view of the above-mentioned deficiencies of the prior art, in a first aspect of the present invention, a simple method for preparing a manganese-based core-shell structured denitration catalyst is provided, employing a homogeneous deposition method, comprising the following steps: (1) Disperse manganese dioxide in a mixture of ethanol and water to form a manganese dioxide dispersion; (2) Using a soluble salt containing the target element as the corresponding precursor, add phosphorus precursor and urea to the manganese dioxide dispersion and mix to obtain a pre-reaction solution; (3) The iron-copper precursor solution formed by dissolving the iron precursor and copper precursor in water and the ethanol solution of tetraethyl silicate were added dropwise to the pre-reaction solution and reacted simultaneously. After the addition was completed, the mixture was continued until the reaction was complete. Then the precipitate produced by the reaction was separated and purified to obtain the reaction product. (4) The reaction product was calcined in air to obtain a manganese-based core-shell denitration catalyst.

[0007] In this preparation method, manganese dioxide, as a catalytically active substance, has diverse sources. It can be obtained from existing manganese dioxide preparations of suitable specifications or synthesized through self-made methods. To obtain manganese dioxide particles with good catalytic effect and ideal structure, preferably, in step (1), the manganese dioxide is prepared by a hydrothermal method, as follows: Potassium permanganate and its stoichiometric amount of ammonium oxalate were dissolved in deionized water to obtain aqueous solutions of potassium permanganate and ammonium oxalate. The aqueous solution of ammonium oxalate was slowly added dropwise to the aqueous solution of potassium permanganate, and the mixture was stirred and then subjected to a hydrothermal reaction. The precipitate produced by the reaction was collected, purified, and then calcined in air to obtain manganese dioxide.

[0008] More preferably, the concentration of the potassium permanganate solution is 0.3~0.7 mol / L, and the concentration of the ammonium oxalate solution is 0.1~0.4 mol / L.

[0009] More preferably, the hydrothermal reaction is carried out at a temperature of 150~200℃ for a time of 12~36h.

[0010] More preferably, the calcination temperature is 400~550℃ and the time is 3~8h.

[0011] Preferably, in step (2), the phosphorus precursor includes diammonium dihydrogen phosphate or diammonium hydrogen phosphate.

[0012] Preferably, in step (2), the concentration of phosphorus precursor is 0.01~0.04 mol / L and the concentration of urea is 1.5~2.5 mol / L.

[0013] Preferably, in step (3), the iron precursor includes ferric nitrate or ferric acetate, and the copper precursor includes copper nitrate or copper acetate.

[0014] Preferably, in step (3), the concentration of the iron precursor solution is 0.01~0.06 mol / L, the concentration of the copper precursor solution is 0.02~0.08 mol / L, and the concentration of the tetraethyl silicate ethanol solution is 0.1~0.4 mol / L.

[0015] Preferably, the molar ratio of phosphorus in the phosphorus precursor to manganese in manganese dioxide (P / Mn) is 0.1~0.15, the molar ratio of iron in the iron precursor to manganese in manganese dioxide (Fe / Mn) is 0.15~0.25, the molar ratio of copper in the copper precursor to manganese in manganese dioxide (Cu / Mn) is 0.2~0.3, the molar ratio of silicon in the tetraethyl silicate to manganese in manganese dioxide (Si / Mn) is 0.4~0.7, and the molar ratio of urea to the sum of the molar amounts of iron in the iron precursor and copper in the copper precursor (urea / Fe+Cu) is 20~40.

[0016] Preferably, in step (3), the total time for the drop addition is 20-30 hours, the reaction temperature is 60-80°C, and the reaction continues for 12-24 hours after the drop addition is completed to ensure a complete reaction.

[0017] Preferably, in step (4), the temperature of the calcination treatment is 400~500℃ and the time is 5~10h.

[0018] In this invention, four elements—iron, copper, silicon, and phosphorus—are introduced. An oxide layer containing these elements is formed on the surface of manganese dioxide by calcination. This layer is a mixture of iron oxide (Fe₂O₃), ferrous oxide (FeO), copper oxide (CuO), cuprous oxide (Cu₂O), silicon dioxide (SiO₂), copper phosphate (Cu₃(PO₄)₂), iron phosphate (FePO₄), and phosphorus pentoxide (P₂O₅). The selection of these elements is based on existing technological shortcomings. When iron and copper are introduced alone or simultaneously, the resulting catalysts, while exhibiting similar catalytic performance, have poor sulfur resistance. When silicon is introduced alone, its catalytic performance is poor and fails to meet requirements. Furthermore, the presence of iron or copper and silicon results in poor catalyst activity. Therefore, this invention introduces these elements. The principle is that when iron, copper, and silicon are present simultaneously, electron transfer occurs between iron and copper, allowing iron ions (Fe₂O₃, FeO, and CuO) to increase their activity. 3+ ) and cuprous ions (Cu + The increased content of ions is beneficial to improving the performance of the catalyst; while silicon increases the content of surface active oxygen, and the abundant hydroxyl groups (-OH) on the surface enhance the acidity of the catalyst surface and inhibit the adsorption of sulfur dioxide (SO2) during catalysis; the introduction of phosphorus forms some copper phosphate and iron phosphate, which further enriches the hydroxyl groups on the surface and inhibits the conversion of sulfur dioxide to more toxic sulfur trioxide (SO3) on the catalyst surface, thereby strengthening the low-temperature sulfur resistance of the catalyst.

[0019] From a physical structure perspective, sulfur dioxide can react with the inner manganese dioxide and the outer copper and iron layers before the manganese dioxide. From a reaction perspective, iron and copper act as sacrificial agents, reacting with sulfur dioxide first to form metal sulfates, thus protecting the inner manganese dioxide. Based on these principles, in practical catalytic applications, the oxide layer, as the outer protective layer, reacts more readily with sulfur dioxide at low temperatures (50~200℃) to form metal sulfates, protecting manganese dioxide from poisoning. At high temperatures (200~300℃), the metal sulfates formed on the outer layer (such as copper sulfate, ferric sulfate, etc.) can serve as active sites, as can manganese dioxide. Furthermore, the metal sulfates formed on the outer layer can react with ammonia (NH3) and nitric oxide (NO) to decompose into sulfur dioxide and metal active sites, further enhancing the catalyst's sulfur resistance. Based on this, the manganese-based core-shell structured denitrification catalyst of the present invention can not only serve as an anti-sulfur layer, but also as an active site to participate in the denitrification and oxidation reactions. It can simultaneously complete denitrification and the removal of carbon monoxide and volatile organic compounds within the operating temperature range of 50~350℃.

[0020] In a second aspect of the present invention, a manganese-based core-shell structured denitrification catalyst is provided, which is prepared using the method of the first aspect of the present invention.

[0021] In a third aspect of the invention, the application of the core-shell structured denitration catalyst of the second aspect of the invention is provided, specifically its application as a catalytic material in denitration reactions and oxidation reactions of carbon monoxide and volatile organic compounds.

[0022] Compared with the prior art, the present invention has the following advantages and beneficial effects: This invention provides a method for preparing a manganese-based core-shell structured denitration catalyst, which adopts a homogeneous deposition method and has the characteristics of simple process and excellent comprehensive performance of finished product.

[0023] This invention provides a manganese-based core-shell structured denitrification catalyst that can remove multiple pollutants in combination. It has strong sulfur resistance and high catalytic selectivity, and can efficiently complete denitrification as well as the oxidation of carbon monoxide and volatile organic compounds.

[0024] This invention also provides the application of manganese-based core-shell structured denitrification catalysts, which have broad prospects as catalytic materials in the combined removal of multiple pollutants. Attached Figure Description

[0025] Figure 1 The image is a scanning electron microscope (SEM) image of MnO2@FeCuSiP. Figure 2 This is a magnified view of a scanning electron microscope (SEM) image of MnO2@FeCuSiP. Figure 3The results show the denitrification performance of MnO2@FeCuSiP. Figure 4 The results show the oxidation performance of MnO2@FeCuSiP on carbon monoxide and toluene. Figure 5 NO was tested for sulfur resistance properties of MnO2@FeCuSiP and MnO2@FeCuSi. x Conversion rate test results; Figure 6 The results of carbon monoxide oxidation rate test for the sulfur resistance properties of MnO2@FeCuSiP and MnO2@FeCuSi; Figure 7 The results of toluene oxidation rate test for sulfur resistance of MnO2@FeCuSiP and MnO2@FeCuSi; Figure 8 MnO2@FeCuSiP, MnO2@Fe 0.15 CuSiP, MnO2@FeCu 0.2 SiP, MnO2@FeCuSiP 0.1 MnO2@FeCuSiP 0.15 NO x Conversion rate test results; Figure 9 MnO2@FeCuSiP, MnO2@Fe 0.15 CuSiP, MnO2@FeCu 0.2 SiP, MnO2@FeCuSiP 0.1 MnO2@FeCuSiP 0.15 The results of the carbon monoxide oxidation rate test; Figure 10 MnO2@FeCuSiP, MnO2@Fe 0.15 CuSiP, MnO2@FeCu 0.2 SiP, MnO2@FeCuSiP 0.1 MnO2@FeCuSiP 0.15 The results of the toluene oxidation rate test; Figure 11 MnO2@FeCuSiP, MnO2@FeCuSiP 0.1 MnO2@FeCuSiP 0.15 NO2- of sulfur resistance test x Conversion rate test results; Figure 12 MnO2@FeCuSiP, MnO2@FeCuSiP 0.1 MnO2@FeCuSiP 0.15The results of the carbon monoxide oxidation rate test for the sulfur resistance properties test; Figure 13 MnO2@FeCuSiP, MnO2@FeCuSiP 0.1 MnO2@FeCuSiP 0.15 The results of the toluene oxidation rate test for sulfur resistance properties. Detailed Implementation

[0026] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0027] In the following embodiments: Manganese dioxide was prepared in the laboratory, and its preparation method is as follows: Dissolve 1.58 g of potassium permanganate in 20 mL of deionized water, and dissolve 0.71 g of ammonium oxalate in 20 mL of deionized water. Slowly add the resulting ammonium oxalate solution to the potassium permanganate solution while stirring continuously. Then, place the mixed solution into a 100 mL hydrothermal reactor and react hydrothermally at 180 °C for 15 h. Finally, wash the obtained precipitate five times with deionized water, dry it under vacuum at 60 °C for 12 h, and then calcine it in air at 400 °C for 5 h to obtain manganese dioxide particles.

[0028] Example 1 The preparation method of manganese-based core-shell structured denitration catalyst is as follows: (1) Take 0.869g of manganese dioxide particles and place them in a mixed solution of 80mL of deionized water and ethanol (3:5 v / v), and disperse them by ultrasonic vibration for 1h to form a manganese dioxide dispersion. (2) Add 0.150g of ammonium dihydrogen phosphate and 9g of urea to the obtained manganese dioxide dispersion, and stir for 1h to obtain a pre-reaction solution; (3) Dissolve 0.808g of ferric nitrate nonahydrate and 0.725g of copper nitrate trihydrate in 50mL of deionized water, and dissolve 1.041g of tetraethyl silicate in 20mL of ethanol. Add the two solutions slowly to the pre-reaction solution and react for 20h. During this process, keep the water bath at 60℃ and stir. After the addition is complete, keep the water bath temperature constant and continue stirring for 12h to make the reaction complete. Then separate the precipitate produced by the reaction, wash with deionized water, and dry under vacuum at 60℃ for 12h to obtain the reaction product. (4) The reaction product was calcined in an air atmosphere at 450°C for 8 hours to obtain a manganese-based core-shell denitration catalyst, which was named MnO2@FeCuSiP.

[0029] The microstructure of the manganese-based core-shell denitration catalyst in this embodiment was observed using scanning electron microscopy (SEM). The resulting images and their magnified partial views are shown in the following figures. Figure 1 , 2 As shown. By Figure 1 It can be seen that the catalyst morphology generally exhibits a relatively smooth spherical structure; from Figure 2 The magnified image clearly shows the internal core and the external shell, indicating that a core-shell structured catalyst has been successfully prepared.

[0030] Example 2 In this embodiment, a catalyst prepared using the method steps of Example 1 but without the addition of ammonium dihydrogen phosphate is used as a comparative example. This comparative catalyst is denoted as MnO2@FeCuSi.

[0031] Two manganese-based core-shell denitration catalysts, MnO2@FeCuSiP and MnO2@FeCuSi, were applied to the NH3-SCR denitration reaction and the oxidation reaction of carbon monoxide and volatile organic compounds to test the comprehensive performance of the catalysts.

[0032] Sulfur dioxide was added to the reaction atmosphere to test the catalyst's sulfur resistance characteristics over 36 hours. Catalyst performance testing was conducted in a fixed-bed quartz tube with an inner diameter of 10 mm. A quartz sieve was placed in the center to hold 0.7 g of catalyst. The catalyst particle size was 40-60 mesh. The simulated flue gas consisted of 5000 ppm CO, 1000 ppm toluene (representing VOCs), 500 ppm NO, 500 ppm NH3, 15% O2, and 5% H2O, with N2 as makeup gas. The space velocity was 60000 h⁻¹. -1 The reaction apparatus was heated from 50°C to 350°C using a programmed temperature increase. The concentrations of various pollutants at the outlet were measured at specific temperatures, and NO was calculated using the following formula. x Conversion rate, nitrogen selectivity, CO and toluene oxidation rates:

[0033]

[0034]

[0035]

[0036] In the formula, the subscript "in" represents the pollutant concentration input for testing, and "out" represents the concentration of each pollutant detected at the outlet.

[0037] Figure 3This reflects the denitrification performance of the MnO2@FeCuSiP catalyst. It can be found that the catalyst maintains a denitrification efficiency exceeding 80% between 50 and 350℃. At low temperatures (50–150℃), the catalyst's denitrification performance is also above 80%, indicating its suitability for low-temperature flue gas denitrification. Even above 200℃, the catalyst maintains high denitrification efficiency and nitrogen selectivity, demonstrating its ability to suppress excessive ammonia oxidation at medium to high temperatures, ensuring good denitrification performance even at these temperatures.

[0038] Figure 4 The results reflect the oxidation performance of the MnO2@FeCuSiP catalyst for carbon monoxide and volatile organic compounds (toluene). The results show that over 80% oxidation rates of carbon monoxide and toluene can be achieved on this catalyst at 130℃, demonstrating excellent low-temperature oxidation capabilities for both. Figure 3 It can be observed that the MnO2@FeCuSiP catalyst not only exhibits excellent reduction performance but also good oxidation capacity, which is related to the core-shell structure of the catalyst. At low temperatures, iron, copper, and the internal manganese dioxide can all serve as active oxidation sites for carbon monoxide and toluene. At this temperature, the reduction performance of the internal manganese dioxide is also good, and the overall reduction performance of the catalyst is also excellent. At medium and high temperatures, ammonia gas more easily combines with the hydroxyl groups on the surface of the outer shell, and then reacts with nitric oxide to generate nitrogen gas, thus achieving high denitrification efficiency and nitrogen selectivity at medium and high temperatures. At this temperature, the highly oxidizing manganese dioxide serves as the oxidation site for carbon monoxide and toluene. Therefore, the core-shell structure achieves the separation of different reaction sites, balancing the oxidation and reduction capabilities of the catalyst.

[0039] The sulfur resistance characteristics of the catalyst were tested at 150℃ over 36 hours, simulating real flue gas by adding 500 ppm SO2. First, the MnO2@FeCuSiP or MnO2@FeCuSi catalyst was stabilized for 3 hours in a sulfur dioxide-free atmosphere. Then, sulfur dioxide was introduced, and the concentrations of various pollutants at the outlet were measured at different time points. The concentrations of flue gas components before and after the reaction were measured online using a Gasmet DX 400 Fourier transform infrared spectroscopy (FTIR) analyzer and a gas chromatograph. At each temperature set in the experiment, the concentrations of each pollutant were recorded after the experiment reached steady state.

[0040] Figures 5-7 A comparison of the resistance studies of two catalysts, MnO2@FeCuSiP and MnO2@FeCuSi, reflects their respective resistance to NO under high concentrations of sulfur dioxide interference. xConversion rate, carbon monoxide oxidation rate, and toluene oxidation rate. A comparison of the results in the figure shows that the introduction of phosphorus significantly improved the overall sulfur resistance of the catalyst. After 12 hours of testing, compared to the MnO2@FeCuSi catalyst, the MnO2@FeCuSiP catalyst exhibited significantly lower NO conversion rate. x The conversion rate, carbon monoxide oxidation rate, and toluene oxidation rate were significantly improved by 7.9%, 18.2%, and 6.3%, respectively. Even at relatively low temperatures such as 150℃, the MnO2@FeCuSiP catalyst maintained excellent denitrification performance and oxidation performance for carbon monoxide and toluene within 36 h. This is because the addition of phosphorus increases the number of hydroxyl groups on the surface, while generating iron phosphate and copper phosphate, which further inhibits the adsorption of sulfur dioxide on the surface and its conversion to sulfur trioxide, which is more toxic to the catalyst, thereby improving the catalyst's sulfur resistance.

[0041] Example 3 The difference between this embodiment and Example 1 is that, in the preparation process, 0.606 g of ferric nitrate nonahydrate and 0.725 g of copper nitrate trihydrate are dissolved in 50 mL of deionized water, while the other preparation processes remain unchanged. The resulting catalyst is denoted as MnO2@Fe. 0.15 CuSiP, where the numerical subscript 0.15 represents the molar ratio of Fe to Mn.

[0042] Example 4 The difference between this embodiment and Example 1 is that, in the preparation process, 0.808g of ferric nitrate nonahydrate and 0.483g of copper nitrate trihydrate are dissolved in 50mL of deionized water, while the other preparation processes remain unchanged. The resulting catalyst is denoted as MnO2@FeCu. 0.2 In SiP, the numerical subscript 0.2 represents the molar ratio of Cu to Mn.

[0043] Example 5 The difference between this embodiment and Example 1 is that, during the preparation process, 0.115g of ammonium dihydrogen phosphate was added to the obtained manganese dioxide dispersion. All other preparation processes remained unchanged. The resulting catalyst was designated MnO2@FeCuSiP. 0.1 The numerical subscript 0.1 represents the molar ratio of P to Mn.

[0044] Example 6 The difference between this embodiment and Example 1 is that, during the preparation process, 0.173g of ammonium dihydrogen phosphate was added to the obtained manganese dioxide dispersion. All other preparation processes remained unchanged. The resulting catalyst was designated MnO2@FeCuSiP. 0.15 The numerical subscript 0.15 represents the molar ratio of P to Mn.

[0045] NO for catalysts with different contents of Fe, Cu and P mentioned above xConversion rate, CO oxidation rate, and toluene oxidation rate were tested, and the test results are as follows: Figures 8-10 As shown, at 150°C, the NOx conversion rate of all catalysts ranged from 97.2% to 100%, the CO oxidation rate ranged from 89% to 100%, and the toluene oxidation rate ranged from 85% to 93%. It can be observed that, within the scope defined by this invention, all catalysts exhibit excellent NOx conversion efficiency. x In terms of the combined removal performance of CO and toluene, the MnO2@FeCuSiP catalyst in this invention is the best performing catalyst.

[0046] The SO2 poisoning resistance characteristics of the catalysts with different P contents were tested, and the test results are as follows: Figures 11-13 As shown in the figure. After 24 hours of testing, it was found that the NOx conversion rate of all catalysts exceeded 87.25%, the CO oxidation rate exceeded 89.54%, and the toluene oxidation rate exceeded 80.68%. Therefore, it can be seen that within the range specified in this invention, the addition of P can give the catalyst excellent resistance to SO2 poisoning, among which the MnO2@FeCuSiP catalyst has the best resistance to SO2 poisoning.

[0047] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for preparing a manganese-based core-shell structured denitration catalyst, employing a homogeneous deposition method, characterized in that, Includes the following steps: (1) Disperse manganese dioxide in a mixture of ethanol and water to form a manganese dioxide dispersion; (2) Using a soluble salt containing the target element as the corresponding precursor, add phosphorus precursor and urea to the manganese dioxide dispersion and mix to obtain a pre-reaction solution; (3) The iron-copper precursor solution formed by dissolving the iron precursor and copper precursor in water and the ethanol solution of tetraethyl silicate were added dropwise to the pre-reaction solution and reacted simultaneously. After the addition was completed, the mixture was continued until the reaction was complete. Then the precipitate produced by the reaction was separated and purified to obtain the reaction product. (4) The reaction product is placed in an air atmosphere for calcination treatment to obtain a manganese-based core-shell structure denitration catalyst. During the calcination treatment, four elements, iron, copper, silicon and phosphorus, are introduced. Through calcination, a compound layer containing the corresponding elements is formed on the surface of manganese dioxide. The compound layer is a mixture of iron oxide, ferrous oxide, copper oxide, cuprous oxide, silicon dioxide, copper phosphate, iron phosphate and phosphorus pentoxide.

2. The method according to claim 1, characterized in that, In step (1), the manganese dioxide is produced by a hydrothermal method, as follows: Potassium permanganate and its stoichiometric amount of ammonium oxalate were dissolved in deionized water to obtain aqueous solutions of potassium permanganate and ammonium oxalate. The aqueous solution of ammonium oxalate was slowly added dropwise to the aqueous solution of potassium permanganate, and the mixture was stirred and then subjected to a hydrothermal reaction. The precipitate produced by the reaction was collected, purified, and then calcined in air to obtain manganese dioxide.

3. The method according to claim 2, characterized in that: The concentration of the potassium permanganate solution is 0.3~0.7 mol / L, and the concentration of the ammonium oxalate aqueous solution is 0.1~0.4 mol / L; the temperature of the hydrothermal reaction is 150~200℃, and the time is 12~36h; the temperature of the calcination is 400~550℃, and the time is 3~8h.

4. The method according to claim 1, characterized in that: In step (2), the phosphorus precursor includes ammonium dihydrogen phosphate or diammonium hydrogen phosphate; in step (3), the iron precursor includes ferric nitrate or ferric acetate, and the copper precursor includes copper nitrate or copper acetate.

5. The method according to claim 1, characterized in that: In terms of molar proportions, the ratio of phosphorus to manganese in manganese dioxide in the phosphorus precursor is 0.1~0.15; the ratio of iron to manganese in manganese dioxide in the iron precursor is 0.15~0.25; the ratio of copper to manganese in manganese dioxide in the copper precursor is 0.2~0.3; the ratio of silicon to manganese in manganese dioxide in tetraethyl silicate is 0.4~0.7; and the ratio of the sum of the molar amounts of iron in the iron precursor and copper in the copper precursor is 20~40.

6. The method according to claim 1, characterized in that: In step (2), the concentration of the phosphorus precursor is 0.01~0.04 mol / L, and the concentration of urea is 1.5~2.5 mol / L; in step (3), the concentration of the iron precursor solution is 0.01~0.06 mol / L, the concentration of the copper precursor solution is 0.02~0.08 mol / L, and the concentration of the tetraethyl silicate ethanol solution is 0.1~0.4 mol / L.

7. The method according to claim 1, characterized in that: In step (3), the total time for the drop addition is 20-30 hours, the reaction temperature is 60-80°C, and the reaction continues for 12-24 hours after the drop addition is completed.

8. The method according to claim 1, characterized in that: In step (4), the calcination treatment is performed at a temperature of 400-500°C for 5-10 hours.

9. A manganese-based core-shell structured denitration catalyst, characterized in that: It is made by means of any one of claims 1 to 8.

10. The application of a manganese-based core-shell structured denitrification catalyst as described in claim 9, characterized in that: Applications of it as a catalytic material in denitrification reactions and oxidation reactions of carbon monoxide and volatile organic compounds.

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