Preparation method of manganese modified vanadium-based denitration catalyst suitable for high-concentration NO2 environment

Abstract

The application relates to the technical field of catalyst preparation, and discloses a preparation method of a manganese-modified vanadium-based denitration catalyst suitable for a high-concentration NO2 environment; the catalyst is modified by Mn, can keep a denitration conversion rate of more than 95% for high-concentration NO2 in a wide temperature range of 200-400 DEG C, and solves the problems of a narrow activity window (300-400 DEG C) and poor low-temperature activity of a traditional vanadium-based catalyst; the V2O5-WO3 / TiO2 catalyst is modified by introducing Mn through an equal-volume impregnation method, the Mn loading is optimized to 3-8 wt%, the prepared V3W3Mn5 / TiO2 catalyst keeps a denitration conversion rate of more than 95% for high-concentration NO2 (6000 ppm) in a wide temperature range of 200-400 DEG C, the catalyst can stably operate below 400 DEG C, and catalyst sintering inactivation caused by high-concentration NO2 reaction heat release is avoided; the catalyst of the application can still keep excellent denitration activity under the conditions of 10 vol.% water vapor, 0.056 wt% UO3 and 6300 h ‑1 high space velocity, meets the complex working condition requirements of spent fuel post-treatment, and the like.

Description

Technical Field

[0001] This invention relates to the field of catalyst preparation technology, specifically to a method for preparing a manganese-modified vanadium-based denitration catalyst suitable for high-concentration NO2 environments. Background Technology

[0002] Nitrogen oxides (NOx) are one of the main sources of air pollution. Among them, nitrogen dioxide (NO2) has strong oxidizing and corrosive properties, posing a particularly serious threat to the ecological environment and human health. In special industrial processes such as spent fuel reprocessing and hypersonic combustion, concentrations as high as 30,000–50,000 mg / Nm³ can be generated. 3 The efficient treatment of ultra-high concentration NO2 exhaust gas has become a key bottleneck for the green transformation of related industries.

[0003] Selective catalytic reduction (SCR) technology is currently the mainstream technology for industrial flue gas denitrification. Vanadium-based catalysts (such as V2O5-WO3 / TiO2) have been widely used in stationary source flue gas denitrification, such as coal-fired power plants, due to their excellent high-temperature activity and controllable cost. However, when traditional vanadium-based catalysts are directly applied to high-concentration NO2 denitrification, the following prominent problems exist: First, the standard SCR reaction (4NO+4NH3+O2→4N2+6H2O) is relatively slow, while a faster SCR reaction (4NH3+2NO+2NO2→4N2+6H2O) is desired under high-concentration NO2 conditions. However, the activity temperature window of traditional catalysts is narrow (usually 300-400℃), and their activity decreases significantly at low temperatures. Second, the SCR reaction involving high-concentration NO2 is accompanied by violent exothermic reactions, which can easily lead to "runaway temperatures" in the catalyst bed, causing sintering and deactivation of active components. Third, existing catalysts have insufficient adsorption and activation capacity for NO2 under low-temperature conditions (<250℃), making it difficult to meet the requirements for high-efficiency denitrification over a wide temperature range.

[0004] To improve the low-temperature activity and wide-temperature adaptability of vanadium-based catalysts, researchers have attempted to modify them by adding transition metal promoters. Studies have shown that manganese (Mn) possesses abundant variable valence states (Mn... 2+ Mn 3+ Mn 4+ Mn-modified vanadium-based catalysts possess excellent low-temperature redox capabilities, effectively promoting the generation of active oxygen species on the catalyst surface and the adsorption and activation of NO2. However, existing preparation methods for Mn-modified vanadium-based catalysts are mostly designed for conventional NOx concentrations or low-temperature conditions, lacking a systematic preparation process specifically suitable for high-concentration NO2 environments. Furthermore, the influence of key parameters such as Mn loading and calcination conditions on the denitrification performance of the catalyst under high NO2 concentrations remains unclear. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing a manganese-modified vanadium-based denitration catalyst suitable for high-concentration NO2 environments, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a manganese-modified vanadium-based denitration catalyst suitable for high-concentration NO2 environments, comprising the following steps:

[0007] Step S1: Using anatase TiO2 as a carrier, weigh a certain amount of TiO2 powder;

[0008] Step S2: Prepare a mixed solution containing vanadium precursor, tungsten precursor and manganese precursor, add oxalic acid as a co-solvent, stir until completely dissolved to obtain the precursor solution;

[0009] Step S3: Mix the TiO2 powder described in step S1 with the precursor liquid described in step S2 using an equal volume impregnation method, and stir until the carrier powder is completely impregnated and no free water appears, to obtain an impregnation mixture;

[0010] Step S4: Place the impregnation mixture described in step S3 in a drying oven and dry it at 80-120°C for 8-16 hours;

[0011] Step S5: Place the dried product from step S4 into a muffle furnace and calcine it at 400-600℃ for 3-6 hours. After natural cooling, grind and sieve to obtain a manganese-modified vanadium-based denitrification catalyst.

[0012] The catalyst has a V2O5 loading of 2-5 wt%, a WO3 loading of 2-5 wt%, and a MnO2 loading of 3-8 wt%, with each loading amount based on the mass of the TiO2 support.

[0013] Preferably, the catalyst has a V2O5 loading of 3 wt%, a WO3 loading of 3 wt%, and a MnO2 loading of 5 wt%.

[0014] Preferably, in step S2, the vanadium precursor is ammonium metavanadate, the tungsten precursor is ammonium paratungstate, and the manganese precursor is manganese nitrate tetrahydrate or manganese acetate.

[0015] Preferably, the molar ratio of oxalic acid to ammonium metavanadate in step S2 is 1:1 to 3:1.

[0016] Preferably, the drying temperature in step S4 is 105°C and the drying time is 12 hours.

[0017] Preferably, the calcination temperature in step S5 is 500°C and the calcination time is 4 hours.

[0018] Preferably, the mesh size of the sieve in step S5 is 45 to 80 mesh.

[0019] Preferably, the method further includes a step of pretreating the TiO2 support before step S3: drying the TiO2 support at 100-150°C for 2-4 hours.

[0020] Preferably, the high-concentration NO2 environment refers to flue gas conditions with an NO2 concentration of not less than 3000 ppm.

[0021] Preferably, the prepared catalyst is suitable for use in the temperature range of 200–400 °C and the space velocity of 3600 h⁻¹. -1 Under the condition of NO2 concentration of 6000ppm, the NO2 conversion rate is not less than 95%.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] This invention modifies a V₂O₅-WO₃ / TiO₂ catalyst by introducing Mn through an equal-volume impregnation method, optimizing the Mn loading to 3–8 wt% (preferably 5 wt%). The resulting V₃W₃Mn₅ / TiO₂ catalyst maintains a stable denitrification conversion rate of over 95% for high-concentration NO₂ (6000 ppm) over a wide temperature range of 200–400 °C, reaching a maximum of 99.8% at 225 °C. This solves the problems of narrow activity window (300–400 °C) and poor low-temperature activity of traditional vanadium-based catalysts. This invention optimizes the Mn loading and calcination process, enabling the catalyst to operate stably below 400 °C and avoiding catalyst deactivation due to exothermic reactions with high-concentration NO₂. The catalyst of this invention also exhibits good performance under 10 vol.% steam, 0.056 wt% UO₃, and 6300 h⁻¹ conditions. -1 It maintains excellent denitrification activity even under high air velocity conditions, meeting the needs of complex working conditions such as spent fuel reprocessing. Attached Figure Description

[0024] Figure 1 This is a flowchart of a preferred embodiment of the method for preparing a manganese-modified vanadium-based denitration catalyst suitable for high-concentration NO2 environments provided by the present invention.

[0025] Figure 2 The NO2 conversion rate of catalysts with different MnO2 loadings provided by this invention;

[0026] Figure 3 This invention provides a comparison of the denitrification activity of the V3W3Mn5 / TiO2 catalyst under different water vapor concentrations.

[0027] Figure 4 The NO2 conversion rates of different catalysts provided by this invention; Figure 5 This invention provides a comparison chart of catalyst denitrification activity at different space velocities. Figure 6 The diagram shows the change in denitrification activity of the V3W3Mn5 / TiO2 catalyst provided by this invention. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1

[0030] Please see Figure 1-4 As shown, a method for preparing a manganese-modified vanadium-based denitration catalyst suitable for high-concentration NO2 environments includes the following steps:

[0031] First, prepare the following ingredients:

[0032] Carrier: Anatase TiO2 powder, with a specific surface area of ​​approximately 50–100 m². 2 / g;

[0033] Vanadium precursor: ammonium metavanadate (NH4VO3), analytical grade;

[0034] Tungsten precursor: Ammonium paratungstate (NH2) 10 H2(W2O7)6), analytical grade;

[0035] Manganese precursor: manganese nitrate tetrahydrate (MnN2O6·4H2O), analytical grade;

[0036] Cosolvent: Oxalic acid dihydrate (C2H2O2·2H2O), analytical grade.

[0037] Catalyst preparation:

[0038] Step 1: Carrier Pretreatment

[0039] Weigh 10g of anatase TiO2 powder, place it in a drying oven, and dry it at 120℃ for 2 hours to remove the moisture physically adsorbed on the carrier surface. After cooling, set aside for later use.

[0040] Step 2: Prepare the precursor solution

[0041] Calculate the required mass of precursor based on the final catalyst having a V2O5 loading of 3wt%, a WO3 loading of 3wt%, and a MnO2 loading of 5wt%.

[0042] The mass of ammonium metavanadate is as follows: the molar mass of V₂O₅ is 182 g / mol, and the molar mass of ammonium metavanadate is 117 g / mol. A 3 wt% V₂O₅ loading corresponds to 10 g TiO₂, requiring 0.3 g of V₂O₅. Therefore, the calculated mass of ammonium metavanadate is approximately 0.3 × (117 / 182) ≈ 0.193 g.

[0043] Ammonium paratungstate mass: WO3 molar mass is 232 g / mol, ammonium paratungstate (calculated as WO3) molar mass is approximately 1174 g / mol (containing 6 WO3 molecules). Loading 3 wt% WO3 requires 0.3 g of WO3, which translates to an ammonium paratungstate mass of approximately 0.3 × (1174 / (6 × 232)) ≈ 0.253 g.

[0044] Mass of manganese nitrate tetrahydrate: The molar mass of MnO2 is 87 g / mol, and the molar mass of manganese nitrate tetrahydrate is 251 g / mol. 0.5 g of MnO2 is needed to load 5 wt% MnO2, which translates to a manganese nitrate tetrahydrate mass of approximately 0.5 × (251 / 87) ≈ 1.443 g.

[0045] Place the weighed ammonium metavanadate, ammonium paratungstate, and manganese nitrate tetrahydrate in the same beaker, and add approximately 20 mL of deionized water. Ammonium metavanadate is sparingly soluble in water; therefore, add oxalic acid at a molar ratio of ammonium metavanadate to oxalic acid of 1:2 (approximately 0.193 g of ammonium metavanadate is 1.65 mmol, requiring approximately 0.42 g of oxalic acid). Place the beaker on a magnetic stirrer and stir in a 60°C water bath until all solids are completely dissolved, yielding a clear and transparent precursor solution. Add deionized water to bring the total volume of the precursor solution to approximately the saturated water absorption capacity of the TiO2 support (preliminary experiments indicate that the saturated water absorption capacity of 10 g TiO2 is approximately 8–10 mL). In this example, the volume is adjusted to 9 mL.

[0046] Step 3: Implanting with equal volume

[0047] Add 10g of TiO2 powder after the pretreatment in step one to the precursor solution in step two, and stir continuously on a magnetic stirrer until the TiO2 powder is completely impregnated and no free water appears, to obtain a wet impregnation mixture.

[0048] Step 4: Drying

[0049] The wet impregnation mixture was transferred to a ceramic evaporating dish and placed in a drying oven at 105°C for 12 hours to completely remove the free water from the mixture.

[0050] Step 5: Calcination

[0051] The dried product was removed and allowed to cool to room temperature before being transferred to a muffle furnace. The temperature was increased to 500°C at a rate of 5°C / min, and calcined in air at 500°C for 4 hours. After calcination, it was allowed to cool naturally to room temperature.

[0052] Step Six: Grinding and Sieving

[0053] The calcined block catalyst was taken out, gently ground with an agate mortar, passed through a 60-mesh standard sieve, and particles of 45-80 mesh (about 180-350 μm) were collected to obtain a manganese-modified vanadium-based denitrification catalyst with V2O5 loading of 3wt%, WO3 loading of 3wt%, and MnO2 loading of 5wt%, denoted as V3W3Mn5 / TiO2.

[0054] Catalyst characterization

[0055] X-ray diffraction (XRD) was used to analyze the crystal phase of the catalyst. The results showed that the catalyst only had characteristic diffraction peaks of anatase TiO2 (2θ=25.3°, 37.8°, 48.0°, 53.9°, 55.1°, 62.7°, etc.), and no characteristic peaks of V2O2, WO3 or MnO2 were detected. This indicates that the active components are highly dispersed in an amorphous or microcrystalline state on the surface of the TiO2 support.

[0056] The specific surface area and pore structure of the catalyst were determined using nitrogen adsorption-desorption (BET) method. The results showed that the specific surface area of ​​the V3W3Mn5 / TiO2 catalyst was 81.57 m². 2 / g, total pore volume 0.34cm³ 3 / g, with an average pore size of 16.68nm, exhibiting a typical mesoporous structure (type IV isotherm, type H2 hysteresis loop).

[0057] X-ray photoelectron spectroscopy (XPS) was used to analyze the elemental valence states on the catalyst surface. The results showed that the V species on the catalyst surface were in the form of V... 5+ and V 4+ Coexistence, V 4+ / (V) 5+ +V 4+ The proportion was 45.41%; Mn species were mainly Mn 4+ and Mn 3+ Coexistence, Mn 4+ / (Mn) 4+ +Mn 3+ The proportion of oxygen in the total oxygen content was 55.55%; the proportion of surface chemically adsorbed oxygen (Oα) was 30.42%. These characteristics indicate that Mn doping effectively regulated the valence state distribution of V, increased the number of surface active oxygen species, and was beneficial to the low-temperature denitrification reaction.

[0058] The redox performance of the catalyst was tested using hydrogen temperature-programmed reduction (H2-TPR). The results showed that the catalyst exhibited a sharp reduction peak at 467.7℃, corresponding to the synergistic reduction of MnOx and VOx species, indicating that the catalyst has good low-temperature redox capabilities.

[0059] The acidity of the catalyst surface was tested by ammonia temperature-programmed desorption (NH3-TPD). The results showed that the catalyst had two desorption peaks at 370.7℃ and 440.5℃, corresponding to moderately strong Brønsted acid sites. This acid strength is conducive to the adsorption and activation of NH3, while avoiding side reactions.

[0060] Catalyst denitrification performance test

[0061] The denitrification performance of the prepared catalyst was tested in a fixed-bed reactor. The experimental conditions were as follows:

[0062] Simulated flue gas composition: 6000ppm NO2, 6000ppm NH3, 13 vol.% O2, N2 is the balance gas;

[0063] Total gas flow rate: 240 mL / min;

[0064] Catalyst loading: 4 mL;

[0065] Airspeed: 3600 h -1 ;

[0066] Reaction temperature range: 200~400℃.

[0067] The NO2 concentration at the reactor inlet and outlet was detected using a flue gas analyzer, and the NO2 conversion rate was calculated according to formula (1):

[0068] NO2 conversion rate = (1 - [NO2]out / [NO2]in) × 100%

[0069] Test results show (see this manual) Figure 2 ):

[0070] At 200℃, the NO2 conversion rate was 98.23%;

[0071] The highest conversion rate of 99.8% was achieved at 225℃.

[0072] Within a wide temperature range of 200–350℃, the NO2 conversion rate consistently remains above 95%.

[0073] Even at a high temperature of 400℃, the NO2 conversion rate is still higher than 90%.

[0074] Water vapor resistance test

[0075] Based on the above test conditions, 5 vol.% and 10 vol.% water vapor were introduced into the simulated flue gas, respectively, to test the denitrification activity of the catalyst. The results showed (see this specification). Figure 3 ):

[0076] After introducing 5 vol.% water vapor, the NO2 conversion rate at 200℃ decreased from 98.23% to 93.51%.

[0077] After introducing 10 vol.% water vapor, the NO2 conversion rate remained at 90.58% at 200℃.

[0078] When the temperature rises above 300℃, the inhibitory effect of water vapor is significantly weakened, and the conversion rate recovers to over 95%.

[0079] This indicates that the catalyst prepared in this embodiment has excellent resistance to water vapor.

[0080] UO3 poisoning resistance test: The V3W3Mn5 / TiO2 catalyst (UO3 precursor is uranyl nitrate) loaded with 0.056wt% UO3 was prepared according to the method of this embodiment. Under the same test conditions, the NO2 conversion rate of this catalyst was 97.77% at 200℃ and 91.65% at 400℃. Compared with the catalyst without UO3 loading, the activity decreased by no more than 8%, showing good resistance to UO3 poisoning.

[0081] Example 2

[0082] The difference between this embodiment and Example 1 is that the loading of MnO2 is adjusted to 3wt%, i.e., V3W3Mn3 / TiO2 catalyst is prepared. The remaining preparation steps and parameters are the same as in Example 1.

[0083] The denitrification performance was tested according to the method in Example 1. The results showed (see this specification). Figure 2 The V3W3Mn3 / TiO2 catalyst achieved a NO2 conversion rate of 98.34% at 225℃, but the conversion rate gradually decreased above 300℃, dropping to approximately 92% at 400℃. Its low-temperature activity and high-temperature stability were slightly lower than those of the V3W3Mn5 / TiO2 catalyst in Example 1.

[0084] Example 3

[0085] The difference between this embodiment and Example 1 is that the loading of MnO2 is adjusted to 7wt%, i.e., V3W3Mn7 / TiO2 catalyst is prepared. The remaining preparation steps and parameters are the same as in Example 1.

[0086] The denitrification performance test results show (see this manual) Figure 2 The denitrification activity of the V3W3Mn7 / TiO2 catalyst was slightly lower than that of the V3W3Mn5 / TiO2 in the range of 200–400 °C. This is presumably because the excessive Mn loading caused MnOx species to agglomerate on the TiO2 surface, reducing the number of effective active sites.

[0087] Comparative Example 1

[0088] The difference between this comparative example and Example 1 is that no manganese precursor is added, i.e., a V3W3 / TiO2 catalyst (unmodified vanadium-based catalyst) is prepared. The remaining preparation steps and parameters are the same as in Example 1.

[0089] The denitrification performance test results show (see this manual) Figure 4 The denitrification activity of the V3W3 / TiO2 catalyst was significantly lower than that of the Mn-modified catalyst in the temperature range of 200–400℃, especially in the low temperature range (200–250℃) where the NO2 conversion rate was less than 80%, indicating that Mn doping is crucial for improving the denitrification activity over a wide temperature range.

[0090] Example 4: Comparison of different calcination temperatures

[0091] The difference between this embodiment and Example 1 is that the calcination temperatures are set to 400℃, 450℃, 550℃, and 600℃ respectively, while other conditions remain unchanged, to prepare a series of V3W3Mn5 / TiO2 catalysts with different calcination temperatures.

[0092] The results of denitrification performance testing and characterization show that:

[0093] When the calcination temperature is 400℃, the catalyst activity is low, possibly due to incomplete decomposition of the precursor.

[0094] The catalyst exhibits optimal activity and good dispersion of active components when calcined at a temperature of 450–500℃.

[0095] When the calcination temperature is 550℃, the specific surface area of ​​the catalyst begins to decrease, and the activity decreases slightly.

[0096] When the calcination temperature is 600℃, the TiO2 support grains grow, the active components sinter, and the denitrification activity decreases significantly.

[0097] Therefore, the preferred calcination temperature is 500℃.

[0098] Example 5: Denitrification performance at different space velocities

[0099] The denitrification performance of the V3W3Mn5 / TiO2 catalyst prepared in Example 1 was tested at different space velocities, with the space velocity set to 3600 h⁻¹. -1 4500h -1 5400h -1 and 6300h -1 The results show (see this manual) Figure 5 As space velocity increases, the contact time between reactants and catalyst shortens, and the NO2 conversion rate decreases slightly, but even at 6300 h⁻¹, the conversion rate remains relatively stable. -1 Even at high space velocities, the NO2 conversion rate of the catalyst can still be maintained above 88%, demonstrating good high space velocity adaptability.

[0100] Example 6: High-Temperature Deactivation Experiment

[0101] The V3W3Mn5 / TiO2 catalyst prepared in Example 1 was subjected to heating and cooling activity tests within the range of 200–600 °C. The results showed (see this specification). Figure 6 The catalyst exhibited stable activity in the 200–400℃ range; however, the NO2 conversion rate decreased rapidly above 400℃, dropping to 46.07% at 600℃. Partial recovery of activity occurred during cooling, but the activity at the same temperature point was lower than that during heating. Characterization of the catalyst before and after the reaction revealed that high temperature led to a decrease in the catalyst's specific surface area (from 81.57 m² / s²). 2 / g decreased to 60.43m 2 / g), the number of mesopores decreases, while V 5+ Restored to V 4+ and V 3+ Mn 4+ Reduced to Mn 3+ and Mn 2+ The redox cycle is disrupted. This indicates that the optimal operating temperature of the catalyst should not exceed 400℃, otherwise irreversible high-temperature deactivation will occur.

[0102] It should be noted that the manganese-modified vanadium-based denitrification catalyst prepared in this invention is particularly suitable for high-concentration NO2 environments, which refer to flue gas conditions with NO2 concentrations not lower than 3000 ppm. Experimental verification shows that it is effective even at NO2 concentrations as high as 6000 ppm and space velocities of 3600 h⁻¹. -1 Under the conditions of 200-400℃, the catalyst prepared in Example 1 can achieve a NO2 conversion rate of over 95%, which is better than the unmodified catalyst and the catalyst with mismatched Mn loading.

[0103] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0104] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a manganese-modified vanadium-based denitration catalyst suitable for high-concentration NO2 environments, characterized in that, Includes the following steps: Step S1: Using anatase TiO2 as a carrier, weigh a certain amount of TiO2 powder; Step S2: Prepare a mixed solution containing vanadium precursor, tungsten precursor and manganese precursor, add oxalic acid as a co-solvent, stir until completely dissolved to obtain the precursor solution; Step S3: Mix the TiO2 powder described in step S1 with the precursor liquid described in step S2 using an equal volume impregnation method, and stir until the carrier powder is completely impregnated and no free water appears, to obtain an impregnation mixture; Step S4: Place the impregnation mixture described in step S3 in a drying oven and dry it at 80-120°C for 8-16 hours; Step S5: Place the dried product from step S4 into a muffle furnace and calcine it at 400-600℃ for 3-6 hours. After natural cooling, grind and sieve to obtain a manganese-modified vanadium-based denitrification catalyst. The catalyst has a V2O5 loading of 2-5 wt%, a WO3 loading of 2-5 wt%, and a MnO2 loading of 3-8 wt%, with each loading amount based on the mass of the TiO2 support.

2. The method for preparing a manganese-modified vanadium-based denitration catalyst suitable for high-concentration NO2 environments according to claim 1, characterized in that: The catalyst has a V2O5 loading of 3 wt%, a WO3 loading of 3 wt%, and a MnO2 loading of 5 wt%.

3. The method for preparing a manganese-modified vanadium-based denitration catalyst suitable for high-concentration NO2 environments according to claim 1, characterized in that: In step S2, the vanadium precursor is ammonium metavanadate, the tungsten precursor is ammonium paratungstate, and the manganese precursor is manganese nitrate tetrahydrate or manganese acetate.

4. The method for preparing a manganese-modified vanadium-based denitration catalyst suitable for high-concentration NO2 environments according to claim 1, characterized in that: The molar ratio of oxalic acid to ammonium metavanadate in step S2 is 1:1 to 3:

1.

5. The method for preparing a manganese-modified vanadium-based denitration catalyst suitable for high-concentration NO2 environments according to claim 1, characterized in that: The drying temperature in step S4 is 105°C and the drying time is 12 hours.

6. The method for preparing a manganese-modified vanadium-based denitration catalyst suitable for high-concentration NO2 environments according to claim 1, characterized in that: The calcination temperature in step S5 is 500℃ and the calcination time is 4 hours.

7. The method for preparing a manganese-modified vanadium-based denitration catalyst suitable for high-concentration NO2 environments according to claim 1, characterized in that: The mesh size of the sieve described in step S5 is 45 to 80 mesh.

8. The method for preparing a manganese-modified vanadium-based denitration catalyst suitable for high-concentration NO2 environments according to claim 1, characterized in that: The method further includes a step of pretreating the TiO2 support before step S3: drying the TiO2 support at 100-150°C for 2-4 hours.

9. The method for preparing a manganese-modified vanadium-based denitration catalyst suitable for high-concentration NO2 environments according to claim 1, characterized in that: The high-concentration NO2 environment refers to flue gas conditions where the NO2 concentration is not lower than 3000 ppm.

10. The method for preparing a manganese-modified vanadium-based denitration catalyst suitable for high-concentration NO2 environments according to claim 1, characterized in that: The prepared catalyst can be used in the temperature range of 200–400 °C and at a space velocity of 3600 h⁻¹. -1 Under the condition of NO2 concentration of 6000ppm, the NO2 conversion rate is not less than 95%.

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