Molybdenum-manganese composite metal oxide catalysts for NO2 purification, their preparation methods and applications
By preparing a molybdenum-manganese composite metal oxide catalyst, the problems of slow reaction rate and low activity at low temperature in the purification of high-concentration NO2 by commercial catalysts were solved, achieving the effect of efficient NO2 purification at low temperature. It is suitable for selective catalytic reduction of nitrogen oxides in gas turbines and industrial boilers.
Patent Information
- Application Number
- CN202411448735.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-17
- Publication Date
- 2025-11-11
- Estimated Expiration
- 2044-10-17
AI Technical Summary
Existing commercial V2O5-WO3/TiO2 catalysts exhibit slow reaction rates in the purification of high-concentration NO2, failing to effectively suppress the formation of yellow smoke. Furthermore, their activity is low under low-temperature conditions, making it difficult to effectively purify NO2 in the exhaust gas of gas-fired boilers.
A molybdenum-manganese composite metal oxide catalyst was prepared by mixing manganese salt and ammonium molybdate with vanadium-tungsten-titanium composite oxide precursor to form a metal diatomic catalyst. This catalyst was used to purify NO2 at a low temperature of 200℃ to form N2 and H2O, and the NO2 conversion rate was higher than 85% in the temperature range of 200-400℃.
The system achieves highly efficient catalytic reduction of NO2 under low-temperature conditions, with a NO2 conversion rate exceeding 85% while maintaining N2 selectivity. This meets the emission requirements of gas turbines and industrial boilers, and is characterized by low cost and simple process.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of catalyst technology, specifically to a molybdenum-manganese composite metal oxide catalyst for purifying NO2, its preparation method, and its application. Background Technology
[0002] The exhaust gas from gas-fired boilers contains a large amount of nitrogen oxides (NOx). x Of the high-concentration NO2, NO2 accounts for over 50%, forming a large amount of yellow smoke. Commercial ammonia selective catalytic reduction catalysts (V2O5-WO3 / TiO2) face the challenge of slow NO2 reaction rates in purifying high-concentration NO2, failing to effectively suppress yellow smoke formation. Simultaneously, the exhaust gas temperature of gas-fired boilers is relatively low (<300℃), resulting in low denitrification activity of V2O5-WO3 / TiO2. These factors constitute significant bottlenecks currently limiting the development of high-concentration NO2 purification technologies.
[0003] Currently, modification with transition metals (manganese, molybdenum, iron, cobalt, copper, cerium, etc.) is an effective means to improve the low-temperature catalytic activity of V2O5-WO3 / TiO2 catalysts. Its functions include introducing acidic sites to enhance reactant adsorption, providing electron-rich sites to enhance the ability to capture gaseous oxygen molecules, and separating reaction sites in acid and redox cycles to improve catalytic activity. However, effectively constructing metal diatoms is key to preparing highly efficient NO2 purification catalysts. Summary of the Invention
[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a molybdenum-manganese composite metal oxide catalyst for purifying NO2, its preparation method and application, which can achieve efficient catalytic reduction of NO2 to form N2 and H2O at a low temperature of 200℃, and the NO2 conversion rate is higher than 85% in the temperature range of 200-400℃; at the same time, the N2 selectivity is similar to that of V2O5-WO3 / TiO2 catalyst.
[0005] The technical solution of this invention is as follows:
[0006] In a first aspect, the present invention provides a method for preparing a molybdenum-manganese composite metal oxide catalyst for purifying NO2, comprising the following steps:
[0007] S1 mixes and stirs titanium dioxide powder with deionized water to prepare titanium dioxide slurry;
[0008] S2 Dissolve ammonium metavanadate and ammonium metatungstate in oxalic acid, add deionized water and stir until completely dissolved, then add the resulting solution to the titanium dioxide slurry in step S1;
[0009] S3 The mixed solution from step S2 is heated and stirred in a water bath until it clumps together. Then it is taken out and dried to obtain the vanadium-tungsten-titanium composite oxide precursor.
[0010] S4 grinds the vanadium-tungsten-titanium composite oxide precursor into powder, calcines it, and then removes it after it cools naturally to room temperature.
[0011] S5 dissolves manganese salt and ammonium molybdate in formamide and sonicates them. Then, the resulting solution is mixed with vanadium-tungsten-titanium composite oxide precursor powder and stirred continuously under heat preservation conditions. Then, it is transferred to a rotary evaporator for dehydration and drying to obtain a metallic diatomic vanadium-tungsten-titanium composite oxide precursor.
[0012] S6 is prepared by drying the metal diatomic vanadium-tungsten-titanium composite oxide precursor, grinding it, calcining it, and then taking it out after it has cooled naturally to room temperature, thus obtaining the molybdenum-manganese composite metal oxide catalyst.
[0013] Preferably, in step S1, the particle size of the titanium dioxide powder is 30-40 nm, the phase is a single anatase phase, and the concentration of titanium dioxide in the titanium dioxide slurry is 5-10 wt.%.
[0014] Preferably, in step S2, the molar ratio of ammonium metavanadate to oxalic acid is 0.5-0.6:1.
[0015] Preferably, in step S3, the water bath heating temperature is 75-85℃, the drying temperature is 100-120℃, and the drying time is 10-12h.
[0016] Preferably, in step S4, the heating rate during calcination is 5-10℃ / min, the calcination temperature is 500-550℃, and the calcination time is 4-6h.
[0017] Preferably, in step S5, the loading of manganese and molybdenum is 0.9-1 wt.%, the total mass ratio of manganese salt and ammonium molybdate to formamide is 1:100-110, the holding temperature is 85-90℃, and the rotary evaporation temperature is 70-80℃; the manganese salt is manganese nitrate or manganese acetate.
[0018] Preferably, in step S6, the drying temperature is 100-120℃, the drying time is 4-12h, the heating rate during calcination is 5-10℃ / min, the calcination temperature is 500-550℃, and the calcination time is 5-6h.
[0019] Preferably, in step S6, the obtained molybdenum-manganese composite metal oxide catalyst contains 1.8-2 wt.% vanadium and 5-5.6 wt.% tungsten.
[0020] Secondly, the present invention provides a molybdenum-manganese composite metal oxide catalyst for purifying NO2, which is prepared by the above-described method for preparing the molybdenum-manganese composite metal oxide catalyst for purifying NO2.
[0021] Thirdly, the present invention provides the application of the above-mentioned molybdenum-manganese composite metal oxide catalyst for purifying NO2, wherein the reaction temperature of the molybdenum-manganese composite metal oxide catalyst for removing NO2 is 200-400℃.
[0022] Compared with the prior art, the present invention has the following advantages:
[0023] Compared to commercial V2O5-WO3 / TiO2 catalysts, the molybdenum-manganese metal diatomic vanadium-tungsten-titanium composite oxide catalyst prepared in this invention can achieve highly efficient catalytic reduction of NO2 to N2 and H2O at a low temperature of 200℃, with a NO2 conversion rate exceeding 85% in the temperature range of 200-400℃; simultaneously, the N2 selectivity remains similar to that of the V2O5-WO3 / TiO2 catalyst. This catalyst has low raw material costs and a simple preparation process, and can be applied to the selective catalytic reduction of nitrogen oxides in high-concentration NO2 emission scenarios such as gas turbines and industrial boilers, with catalytic activity meeting emission requirements. Attached Figure Description
[0024] Figure 1 These are the catalyst activity evaluation test diagrams for Examples 1 and 2 of the present invention.
[0025] Figure 2 These are the catalyst activity evaluation test diagrams for Examples 1 and Comparative Examples 1-8 of the present invention.
[0026] Figure 3 This is a catalyst stability test diagram from Example 1 of the present invention.
[0027] Figure 4 These are the catalyst activity evaluation test diagrams for Example 1 and Comparative Example 9 of the present invention.
[0028] Figure 5 These are the catalyst activity evaluation test diagrams for Example 1 and Comparative Example 10 of the present invention.
[0029] Figure 6 These are the catalyst activity evaluation test diagrams for Example 1 and Comparative Example 11 of the present invention.
[0030] Figure 7 These are the catalyst activity evaluation test diagrams for Example 1 and Comparative Example 12 of the present invention. Detailed Implementation
[0031] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention.
[0032] Example 1
[0033] This embodiment prepares a molybdenum-manganese metal diatomic vanadium-tungsten-titanium composite oxide catalyst, and the preparation method is as follows:
[0034] S1. Anatase titanium dioxide powder with a particle size range of 30-40 nm is mixed with deionized water at room temperature to form a turbid liquid A with a concentration of 10 wt.%.
[0035] S2 prepares a solution by mixing ammonium metavanadate and oxalic acid at a molar ratio of 0.5:1. After mixing with ammonium metatungstate, deionized water is added and stirred until completely dissolved to form solution B. The turbid solution A and solution B are mixed and stirred continuously for 3 hours.
[0036] S3 The mixed solution from step S2 is heated and stirred in a water bath at 80°C until solidified, and the solid is dried at 100°C for 12 hours to obtain the vanadium-tungsten-titanium composite oxide precursor.
[0037] S4 grinds the vanadium-tungsten-titanium composite oxide precursor into powder, transfers it into a muffle furnace and calcines it at 550°C in air atmosphere for 4 hours with a heating rate of 5°C / min, and takes it out after it cools naturally to room temperature.
[0038] S5 dissolves manganese nitrate and ammonium molybdate in formamide solution, wherein the total mass ratio of manganese nitrate and ammonium molybdate to formamide is 1:100, and then sonicates for 20 min; vanadium-tungsten-titanium composite oxide precursor powder is added to the above solution, and stirred in a 90℃ water bath for 6 h, and then transferred to a rotary evaporator for dehydration and drying at 70℃ to obtain molybdenum-manganese metal diatomic vanadium-tungsten-titanium composite oxide precursor;
[0039] S6 dried the molybdenum-manganese metal diatomic vanadium-tungsten-titanium composite oxide precursor at 100℃ for 12h and then ground it into powder. The powder was then transferred to a muffle furnace and calcined at 550℃ in air atmosphere for 5h with a heating rate of 5℃ / min. After naturally cooling to room temperature, the powder was removed to obtain the molybdenum-manganese metal diatomic vanadium-tungsten-titanium composite oxide catalyst MoMn-VWTi. The catalyst contained 2 wt.% vanadium, 5 wt.% tungsten, 1 wt.% manganese, and 1 wt.% molybdenum.
[0040] Example 2
[0041] This embodiment prepares a molybdenum-manganese metal diatomic vanadium-tungsten-titanium composite oxide catalyst, and the preparation method is as follows:
[0042] S1. Anatase titanium dioxide powder with a particle size range of 30-40 nm is mixed with deionized water at room temperature to form a turbid liquid A with a concentration of 10 wt.%.
[0043] S2 prepares a solution by mixing ammonium metavanadate and oxalic acid at a molar ratio of 0.5:1. After mixing with ammonium metatungstate, deionized water is added and stirred until completely dissolved to form solution B. The turbid solution A and solution B are mixed and stirred continuously for 3 hours.
[0044] S3 The mixed solution from step S2 is heated and stirred in a water bath at 75°C until solidified, and the solid is dried at 110°C for 11 hours to obtain the vanadium-tungsten-titanium composite oxide precursor.
[0045] S4 grinds the vanadium-tungsten-titanium composite oxide precursor into powder, transfers it into a muffle furnace and calcines it at 530℃ in air atmosphere for 5 hours with a heating rate of 6℃ / min, and takes it out after it cools naturally to room temperature.
[0046] S5 dissolves manganese acetate and ammonium molybdate in formamide solution, wherein the total mass ratio of manganese acetate and ammonium molybdate to formamide is 1:105, and then sonicates for 20 min; vanadium-tungsten-titanium composite oxide precursor powder is added to the above solution, and stirred in an 88℃ water bath for 6 h, and then transferred to a rotary evaporator for dehydration and drying at 75℃ to obtain molybdenum-manganese metal diatomic vanadium-tungsten-titanium composite oxide precursor;
[0047] S6 dried the molybdenum-manganese metal diatomic vanadium-tungsten-titanium composite oxide precursor at 110℃ for 10h and then ground it into powder. The powder was then transferred to a muffle furnace and calcined at 530℃ in air atmosphere for 5.5h at a heating rate of 6℃ / min. After naturally cooling to room temperature, the powder was removed to obtain the molybdenum-manganese metal diatomic vanadium-tungsten-titanium composite oxide catalyst MoMn-VWTi. The catalyst contained 1.9 wt.% vanadium, 5.2 wt.% tungsten, 0.95 wt.% manganese, and 0.95 wt.% molybdenum.
[0048] The catalysts prepared in Examples 1 and 2 were subjected to activity evaluation tests under the following conditions: 500 ppm NO2, 500 ppm NH3, 5% O2, with N2 as the balance gas, a total flow rate of 200 mL / min, and a gas hourly space velocity (GHSV) of 60,000 mL·g. -1 ·h -1 .
[0049] The activity evaluation results of the catalysts prepared in Examples 1 and 2 are as follows: Figure 1 As shown. By Figure 1 It can be seen that the MoMn-VWTi catalyst prepared with manganese acetate as the manganese source has higher activity and NO2 conversion rate of over 92%.
[0050] Example 3
[0051] This embodiment prepares a molybdenum-manganese metal diatomic vanadium-tungsten-titanium composite oxide catalyst, and the preparation method is as follows:
[0052] S1. Anatase titanium dioxide powder with a particle size range of 30-40 nm is mixed with deionized water at room temperature to form a turbid liquid A with a concentration of 5 wt.%.
[0053] S2 prepares a solution by mixing ammonium metavanadate and oxalic acid at a molar ratio of 0.6:1, then mixes it with ammonium metatungstate and adds deionized water and stirs until completely dissolved to form solution B. The turbid solution A and solution B are mixed and stirred continuously for 3 hours.
[0054] S3 The mixed solution from step S2 is heated and stirred in a water bath at 85°C until solidified, and the solid is dried at 120°C for 10 hours to obtain the vanadium-tungsten-titanium composite oxide precursor.
[0055] S4 grinds the vanadium-tungsten-titanium composite oxide precursor into powder, transfers it into a muffle furnace and calcines it in an air atmosphere at 500℃ for 6 hours with a heating rate of 10℃ / min, and takes it out after it cools naturally to room temperature.
[0056] S5 dissolves manganese nitrate and ammonium molybdate in formamide solution, wherein the total mass ratio of manganese nitrate and ammonium molybdate to formamide is 1:110, and then sonicates for 20 min; vanadium-tungsten-titanium composite oxide precursor powder is added to the above solution, and stirred in an 85℃ water bath for 6 h, and then transferred to a rotary evaporator for dehydration and drying at 80℃ to obtain molybdenum-manganese metal diatomic vanadium-tungsten-titanium composite oxide precursor;
[0057] S6 dried the molybdenum-manganese metal diatomic vanadium-tungsten-titanium composite oxide precursor at 120℃ for 4 hours, then ground it into powder. The powder was then transferred to a muffle furnace and calcined at 500℃ in air atmosphere for 6 hours at a heating rate of 10℃ / min. After naturally cooling to room temperature, the powder was removed to obtain the molybdenum-manganese metal diatomic vanadium-tungsten-titanium composite oxide catalyst MoMn-VWTi. The catalyst contained 1.8 wt.% vanadium, 5.6 wt.% tungsten, 0.9 wt.% manganese, and 0.9 wt.% molybdenum.
[0058] Example 4
[0059] This embodiment prepares a molybdenum-manganese metal diatomic vanadium-tungsten-titanium composite oxide catalyst, and the preparation method is as follows:
[0060] S1. Anatase titanium dioxide powder with a particle size range of 30-40 nm is mixed with deionized water at room temperature to form a turbid liquid A with a concentration of 8 wt.%.
[0061] S2 prepares a solution by mixing ammonium metavanadate and oxalic acid at a molar ratio of 0.5:1. After mixing with ammonium metatungstate, deionized water is added and stirred until completely dissolved to form solution B. The turbid solution A and solution B are mixed and stirred continuously for 3 hours.
[0062] S3 The mixed solution from step S2 is heated and stirred in a water bath at 75°C until solidified, and the solid is dried at 110°C for 12 hours to obtain the vanadium-tungsten-titanium composite oxide precursor.
[0063] S4 grinds the vanadium-tungsten-titanium composite oxide precursor into powder, transfers it into a muffle furnace and calcines it at 540℃ in air atmosphere for 5 hours with a heating rate of 5℃ / min, and takes it out after it cools naturally to room temperature.
[0064] S5 dissolves manganese nitrate and ammonium molybdate in formamide solution, wherein the total mass ratio of manganese nitrate and ammonium molybdate to formamide is 1:100, and then sonicates for 20 min; vanadium-tungsten-titanium composite oxide precursor powder is added to the above solution, and stirred in a 90℃ water bath for 6 h, and then transferred to a rotary evaporator for dehydration and drying at 70℃ to obtain molybdenum-manganese metal diatomic vanadium-tungsten-titanium composite oxide precursor;
[0065] S6 dried the molybdenum-manganese metal diatomic vanadium-tungsten-titanium composite oxide precursor at 100℃ for 12h and then ground it into powder. The powder was then transferred to a muffle furnace and calcined at 540℃ in air atmosphere for 5h with a heating rate of 5℃ / min. After naturally cooling to room temperature, the powder was removed to obtain the molybdenum-manganese metal diatomic vanadium-tungsten-titanium composite oxide catalyst MoMn-VWTi. The catalyst contained 2 wt.% vanadium, 5 wt.% tungsten, 1 wt.% manganese, and 1 wt.% molybdenum.
[0066] Comparative Example 1
[0067] The difference between Comparative Example 1 and Example 1 is that steps S5 and S6 are not performed, and the vanadium-tungsten-titanium composite oxide catalyst VWTi is obtained.
[0068] Comparative Example 2
[0069] The difference between Comparative Example 2 and Example 1 is that ammonium molybdate is not added in step S5, and the final preparation yields the manganese metal atom vanadium tungsten titanium composite oxide catalyst Mn-VWTi.
[0070] Comparative Examples 3-8
[0071] The difference between Comparative Examples 3-8 and Example 1 is that the ammonium molybdate in step S5 of Example 1 is replaced sequentially with cerium, copper, cobalt, iron, zirconium, and niobium. The resulting catalysts are, in order, cerium-manganese metal diatomic vanadium-tungsten-titanium composite oxide catalyst CeMn-VWTi, copper-manganese metal diatomic vanadium-tungsten-titanium composite oxide catalyst CuMn-VWTi, cobalt-manganese metal diatomic vanadium-tungsten-titanium composite oxide catalyst CoMn-VWTi, iron-manganese metal diatomic vanadium-tungsten-titanium composite oxide catalyst FeMn-VWTi, zirconium-manganese metal diatomic vanadium-tungsten-titanium composite oxide catalyst ZrMn-VWTi, and niobium-manganese metal diatomic vanadium-tungsten-titanium composite oxide catalyst NbMn-VWTi.
[0072] Comparative Example 9
[0073] The difference from Example 1 is that the manganese content in the catalyst is 8 wt.%, and the final prepared molybdenum-manganese metal diatomic vanadium-tungsten-titanium composite oxide catalyst MoMn(8%)-VWTi is obtained.
[0074] Comparative Example 10
[0075] The difference from Example 1 is that the molybdenum content in the catalyst is 10 wt.%, and the final prepared molybdenum-manganese metal diatomic vanadium-tungsten-titanium composite oxide catalyst Mo(10%)Mn-VWTi is obtained.
[0076] Comparative Example 11
[0077] The difference from Example 1 is that in step S4, the calcination temperature is 800℃, and the final molybdenum-manganese metal diatomic vanadium-tungsten-titanium composite oxide catalyst MoMn-(VWTi-800) is prepared.
[0078] Comparative Example 12
[0079] The difference from Example 1 is that in step S6, the calcination temperature is 800℃, and the final prepared molybdenum-manganese metal diatomic vanadium-tungsten-titanium composite oxide catalyst MoMn-VWTi-800 is obtained.
[0080] The catalysts prepared in Example 1 and Comparative Examples 1-12 were subjected to activity evaluation tests under the following conditions: 600 ppm NO. x (100ppm NO, 500ppm NO2), 600ppm NH3, 5% O2, N2 is the balance gas, total flow rate is 200mL / min, gas hourly space velocity (GHSV) is 60000mL·g -1 ·h -1 .
[0081] The activity evaluation results of the catalysts prepared in Example 1 and Comparative Examples 1-12 are as follows: Figure 2 , 4 As shown in -7. (By...) Figure 2 It can be seen that, within the temperature range of 200-400℃, the NO2 conversion rate of the molybdenum-manganese metal diatomic vanadium-tungsten-titanium composite oxide catalyst MoMn-VWTi in Example 1 can be maintained above 85%, which is better than the catalysts prepared in Comparative Examples 1-12.
[0082] The stability of the catalyst prepared in Example 1 was tested under the following conditions: 600 ppm NO. x (100ppm NO, 500ppm NO2), 600ppm NH3, 5% O2, N2 as balance gas, temperature 300℃, total flow rate 200mL / min, gas hourly space velocity (GHSV) 60000mL·g -1 ·h -1 .
[0083] The stability test results of the catalyst prepared in Example 1 are as follows: Figure 3 As shown. By Figure 3 It can be seen that the NO2 conversion rate of the MoMn-VWTi catalyst can be maintained at around 90.5% and the N2 selectivity at around 81.6% within 20 hours, indicating that the catalyst prepared in Example 1 has good stability.
Claims
1. A method for preparing a molybdenum-manganese composite metal oxide catalyst for purifying NO2, characterized in that, Includes the following steps: S1 mixes and stirs titanium dioxide powder with deionized water to prepare titanium dioxide slurry; S2 Dissolve ammonium metavanadate and ammonium metatungstate in oxalic acid, add deionized water and stir until completely dissolved, then add the resulting solution to the titanium dioxide slurry in step S1; S3 The mixed solution from step S2 is heated and stirred in a water bath until it clumps together. Then it is taken out and dried to obtain the vanadium-tungsten-titanium composite oxide precursor. S4 grinds the vanadium-tungsten-titanium composite oxide precursor into powder and then calcines it at a temperature of 500-550℃. After naturally cooling to room temperature, it is taken out. S5 dissolves manganese salt and ammonium molybdate in formamide and sonicates. The resulting solution is then mixed with vanadium-tungsten-titanium composite oxide precursor powder and continuously stirred under heat. The mixture is then transferred to a rotary evaporator for dehydration and drying to obtain a metallic diatomic vanadium-tungsten-titanium composite oxide precursor; the loading of manganese and molybdenum is 0.9-1 wt.%. S6 involves drying the metal diatomic vanadium-tungsten-titanium composite oxide precursor, grinding it, and then calcining it at a temperature of 500-550℃. After naturally cooling to room temperature, the precursor is removed to obtain the molybdenum-manganese composite metal oxide catalyst.
2. The preparation method of the molybdenum-manganese composite metal oxide catalyst for purifying NO2 as described in claim 1, characterized in that, In step S1, the titanium dioxide powder has a particle size of 30-40 nm, the phase is a single anatase phase, and the titanium dioxide concentration in the titanium dioxide slurry is 5-10 wt.%.
3. The preparation method of the molybdenum-manganese composite metal oxide catalyst for purifying NO2 as described in claim 1, characterized in that, In step S2, the molar ratio of ammonium metavanadate to oxalic acid is 0.5-0.6:
1.
4. The preparation method of the molybdenum-manganese composite metal oxide catalyst for purifying NO2 as described in claim 1, characterized in that, In step S3, the water bath heating temperature is 75-85℃, the drying temperature is 100-120℃, and the drying time is 10-12h.
5. The preparation method of the molybdenum-manganese composite metal oxide catalyst for purifying NO2 as described in claim 1, characterized in that, In step S4, the heating rate during calcination is 5-10℃ / min, and the calcination time is 4-6h.
6. The preparation method of the molybdenum-manganese composite metal oxide catalyst for purifying NO2 as described in claim 1, characterized in that, In step S5, the total mass ratio of manganese salt and ammonium molybdate to formamide is 1:100-110, the holding temperature is 85-90℃, and the rotary evaporation temperature is 70-80℃; the manganese salt is manganese nitrate or manganese acetate.
7. The preparation method of the molybdenum-manganese composite metal oxide catalyst for purifying NO2 as described in claim 1, characterized in that, In step S6, the drying temperature is 100-120℃, the drying time is 4-12h, the heating rate during calcination is 5-10℃ / min, and the calcination time is 5-6h.
8. The preparation method of the molybdenum-manganese composite metal oxide catalyst for purifying NO2 as described in claim 1, characterized in that, In step S6, the obtained molybdenum-manganese composite metal oxide catalyst contains 1.8-2 wt.% vanadium and 5-5.6 wt.% tungsten.
9. A molybdenum-manganese composite metal oxide catalyst for purifying NO2, characterized in that, It was prepared by the method for preparing a molybdenum-manganese composite metal oxide catalyst for purifying NO2 as described in any one of claims 1-8.
10. The application of the molybdenum-manganese composite metal oxide catalyst for purifying NO2 as described in claim 9 in the purification of NO2, characterized in that, The reaction temperature for removing NO2 is 200-400℃.