Ultralow-temperature manganese-based SCR (Selective Catalytic Reduction) denitration catalyst and preparation method thereof

Abstract

The invention discloses an ultralow-temperature manganese-based SCR (Selective Catalytic Reduction) denitration catalyst and a preparation method thereof. The SCR catalyst comprises manganese oxide, zirconium oxide and tin oxide, in the catalyst finished product, the content of ZrO2 is 26-32 mol%, the content of SnO2 is 13-16 mol%, and the balance is MnO2 in terms of the total content of metal oxides being 100 mol%; by accurately controlling the contents of manganese oxide, zirconium oxide and tin oxide and the addition amount of cetyltrimethylammonium bromide (CTAB), the pore structure of the SCR catalyst is optimized, the activity and selectivity of the catalyst are improved, the performance of the catalyst is improved, and the catalyst can keep higher denitration efficiency under different working conditions; the conversion rate of the ultralow-temperature SCR catalyst to NO reaches 95% or above under the conditions that the reaction space velocity is 100,000 h <-1 > and the temperature is 80 DEG C, and the conversion rate is maintained at a high level for a long time.

Description

Technical Field

[0001] The invention belongs to the field of catalyst preparation and relates to an ultra-low temperature manganese-based SCR denitration catalyst and a preparation method thereof. Background Art

[0002] Nitrogen oxides (NO x ) is one of the main pollutants emitted during fuel combustion, including nitrogen monoxide (NO) and nitrogen dioxide (NO2). x The emission of nitrogen oxides will not only cause serious environmental pollution, but also have an impact on human health. Therefore, reducing the emission of nitrogen oxides plays a vital role in protecting the ecological environment and human health.

[0003] Selective catalytic reduction (SCR) technology is one of the most mature technologies for controlling nitrogen oxide emissions from stationary sources. SCR technology uses ammonia (NH3) or urea as a reducing agent to reduce NO in flue gas under the action of a catalyst. x Reduced to non-toxic nitrogen (N2) and water (H2O). Currently, SCR technology has been widely used in industrial emission sources such as coal-fired power plants, waste incineration plants and glass factories.

[0004] Taking the widely used vanadium-based catalyst V2O5-WO3 / TiO2 (VWTi) in industry as an example, it has high denitrification activity and good N2 selectivity. However, the optimal reaction temperature of this type of vanadium-based catalyst is usually 300℃~400℃, and the denitrification efficiency is significantly reduced under low temperature (below 200℃), and it is easily affected by alkali metal ions, which limits its wide application under low temperature conditions. With the increasingly stringent emission standards and the increasing demand for low-temperature flue gas treatment, the research and development of new low-temperature SCR catalysts with high denitrification efficiency has begun to attract the attention of many researchers.

[0005] At present, the research and development of low-temperature SCR catalysts has made some progress. Low-temperature catalysts based on manganese, iron, cerium and other transition metals as active components show good low-temperature activity and redox performance. However, most manganese-based catalysts (such as MnO x -CeO2 catalyst) showed high NO in the range of 150℃~250℃ x The conversion rate is high, but its resistance to sulfur and alkali metal poisoning is poor. Although iron-based and cerium-based catalysts have strong anti-sulfur properties, they still have problems such as insufficient low-temperature activity and poor stability in long-term operation. In addition, some studies have proposed the use of nanostructure regulation to improve the performance of catalysts, but actual industrial applications still face great challenges.

[0006] In summary, most of the low-temperature SCR catalysts currently developed have poor catalyst performance in practical applications and cannot achieve ideal results in industrial applications. Therefore, the development of a low-temperature SCR denitrification catalyst with high catalytic activity and high stability is still an urgent problem to be solved. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a manganese-based SCR denitrification catalyst for ultra-low temperature environment and a preparation method thereof. The catalyst has a low optimal reaction temperature, high activity, strong stability, and high resistance to sulfur and alkali metal poisoning.

[0008] The technical solution adopted by the present invention to solve the above technical problems is: an ultra-low temperature manganese-based SCR denitrification catalyst, characterized in that the composition of the SCR catalyst includes manganese oxide (MnO2), zirconium oxide (ZrO2) and tin oxide (SnO2).

[0009] In the catalyst of the present invention, based on the total content of metal oxides as 100 mol%, the content of ZrO2 is 26-32 mol%, the content of SnO2 is 13-16 mol%, and the balance is MnO2; by precisely controlling the contents of manganese oxide (MnO2), zirconium oxide (ZrO2) and tin oxide (SnO2), it is helpful to improve the activity and selectivity of the SCR catalyst, optimize the performance of the SCR catalyst, and enable it to maintain a high denitrification efficiency under different working conditions.

[0010] A method for preparing an ultra-low temperature manganese-based SCR denitration catalyst, characterized by comprising the following preparation steps:

[0011] Step A: preparing a mixed precursor solution of manganese, zirconium and tin;

[0012] Step B: placing the precursor solution in a hydrothermal reactor for hydrothermal reaction;

[0013] Step C: washing the precipitate obtained by the hydrothermal reaction;

[0014] Step D: high temperature calcination;

[0015] Step E: Grind the product obtained in step D to a certain mesh size to obtain a finished SCR catalyst. In the finished SCR catalyst, based on the total content of metal oxides as 100 mol%, the content of ZrO2 is 26-32 mol%, the content of SnO2 is 13-16 mol%, and the remainder is MnO2.

[0016] The specific process of step A is: adding manganese salt to a certain amount of deionized water, stirring and shaking until completely dissolved, adding zirconium salt after dissolution, repeatedly stirring and shaking until completely dissolved, adding tin salt after dissolution again, repeatedly stirring and shaking until completely dissolved, adding a certain amount of hexadecyltrimethylammonium bromide (CTAB) to the resulting solution, and stirring evenly.

[0017] The manganese salt is selected from one or more of manganese acetate, manganese nitrate, manganese chloride, and potassium permanganate; the zirconium salt is selected from one or more of zirconium acetate, zirconium nitrate, and zirconium oxychloride; the tin salt is selected from one or more of tin chloride, stannous chloride, and tin nitrate; the total concentration of metal atoms in the precursor solution is 0.37-0.40 mol / L; and the molar ratio of the amount of CTAB added to the total amount of metal atoms in the solution is 2:1 or 3:1.

[0018] The specific process of step B is: adding ammonia water to the precursor solution, adjusting the pH value of the solution, and stirring evenly at room temperature; after standing for a short time, placing the solution in a hydrothermal kettle for hydrothermal reaction.

[0019] The pH value of the solution is 6.5-7.0; the hydrothermal reaction temperature is 140° C.-180° C.; and the hydrothermal reaction time is 12-16 hours.

[0020] The specific process of step C is: using ethanol and deionized water at a certain temperature to alternately wash the product after the hydrothermal reaction until the impurities in the product are completely removed.

[0021] The temperature of deionized water is 60℃~80℃.

[0022] The specific process of step D is: placing the washed product in an oven to dry overnight, and then calcining it at a certain temperature for a period of time.

[0023] The calcination temperature is 280°C to 330°C, and the calcination time is 4 hours.

[0024] Compared with the prior art, the advantages of the present invention are:

[0025] The present invention proposes a manganese-based SCR denitration catalyst with manganese oxide, zirconium oxide and tin oxide as components in a low-temperature environment and a preparation method thereof. By precisely controlling the content of manganese oxide (MnO2), zirconium oxide (ZrO2) and tin oxide (SnO2), utilizing the high catalytic efficiency of manganese-based catalysts in a low-temperature environment, combining metal oxides of zirconium and tin, the catalytic efficiency of the catalyst is improved, the disadvantage of manganese-based catalysts being easily affected by SO2 and H2O is improved, the catalyst's resistance to alkali metal poisoning is improved, and through the synergistic effect between metals, it has a more excellent performance improvement. Compared with existing catalysts, it has higher catalytic activity and stability and a lower activation temperature. Its performance is mainly achieved through the following aspects:

[0026] 1) Manganese oxide (MnO2) has strong redox ability and can greatly increase the rate of catalytic reaction through the "fast SCR reaction" reaction pathway under low temperature environment; at the same time, its surface is rich in acidic sites, which are helpful for the adsorption and activation process of NH3 in the SCR reaction and increase the reaction rate between NH3 and NO; by compounding zirconium oxide (ZrO2) and tin oxide (SnO2), the acid distribution on the catalyst surface can be further optimized and the catalyst activity can be improved.

[0027] 2) Zirconium oxide (ZrO2) has high thermal stability and strong anti-sulfur performance, which can reduce the adsorption and reaction of SO2 on the catalyst surface, thereby improving the stability of the catalyst in a sulfur-containing environment; since the surface of zirconium oxide has strong acidity, it helps to improve the catalyst's adsorption capacity for NH3 under low temperature conditions, thereby enhancing the activity of low-temperature SCR reaction; and zirconium oxide can play a certain role in resisting alkali metal poisoning, which can reduce the damage of alkali metals to the acidity and activity of SCR catalysts to a certain extent.

[0028] 3) Tin oxide (SnO2) can effectively reduce the activation temperature of the SCR catalyst and enhance the low-temperature denitrification performance of the catalyst; it also has good resistance to sulfur poisoning and surface acidity; the addition of tin oxide can improve the overall wear resistance of the catalyst and increase the service life and long-term stability of the catalyst.

[0029] 4) By precisely controlling the contents of manganese oxide (MnO2), zirconium oxide (ZrO2) and tin oxide (SnO2) and the amount of cetyltrimethylammonium bromide (CTAB) added, the pore structure of the SCR catalyst is optimized, the activity and selectivity of the catalyst are improved, and the performance of the catalyst is enhanced so that it can maintain a high denitrification efficiency under different working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The conversion rates of NO by the catalysts of various embodiments and comparative examples at different temperatures are shown in FIG.

[0031] Figure 2 It is the conversion rate of NO of the catalyst of each example within 200 hours. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below with reference to the embodiments.

[0033] The present invention provides a method for preparing an ultra-low temperature manganese-based SCR denitration catalyst, which comprises the following preparation steps:

[0034] Step A: preparing a mixed precursor solution of manganese, zirconium and tin.

[0035] The specific steps are: add a certain amount of manganese salt into deionized water, stir and shake until it is completely dissolved, add zirconium salt after dissolution, repeat stirring and shaking until it is completely dissolved, add tin salt after it is dissolved again, repeat stirring and shaking until it is completely dissolved, add a certain amount of hexadecyltrimethylammonium bromide (CTAB) into the obtained solution, and stir evenly.

[0036] It is further defined that the manganese salt is selected from one or more of manganese acetate, manganese nitrate, manganese chloride, and potassium permanganate; the zirconium salt is selected from one or more of zirconium acetate, zirconium nitrate, and zirconium oxychloride; and the tin salt is selected from one or more of tin chloride, stannous chloride, and tin nitrate.

[0037] It is further defined that the total concentration of metal atoms in the precursor solution is 0.37 to 0.40 mol / L.

[0038] Preferably, the molar ratio of the amount of CTAB added to the total amount of metal atoms in the solution is 2:1 or 3:1.

[0039] Step B: placing the precursor solution in a hydrothermal reactor for hydrothermal reaction.

[0040] The specific steps are: adding ammonia water to the precursor solution, adjusting the pH value of the solution, and stirring evenly at room temperature; after standing for a short time, placing the solution in a hydrothermal kettle for hydrothermal reaction.

[0041] Preferably, the pH value of the solution is 6.5-7.0; the hydrothermal reaction temperature is 140° C.-180° C.; and the hydrothermal reaction time is 12-16 hours.

[0042] Step C: washing the precipitate obtained from the hydrothermal reaction.

[0043] The specific steps are: using ethanol and deionized water at a certain temperature to alternately wash the product after the hydrothermal reaction until the impurities in the product are completely removed.

[0044] Preferably, the temperature of the deionized water is 60°C to 80°C.

[0045] Step D: high temperature calcination.

[0046] The specific steps are: placing the washed product in an oven to dry overnight, and then calcining it at a certain temperature for a period of time.

[0047] Preferably, the calcination temperature is 280° C. to 330° C., and the calcination time is 4 hours.

[0048] Step E: Grind the product obtained in step D to a certain mesh size to obtain a finished SCR catalyst.

[0049] In the finished ultra-low temperature manganese-based SCR denitration catalyst prepared by the above preparation method, based on the total content of metal oxides as 100 mol%, the content of ZrO2 is 26-32 mol%, the content of SnO2 is 13-16 mol%, and the balance is MnO2.

[0050] Specific comparative examples and embodiments are provided below for detailed description.

[0051] Comparative Example:

[0052] Add 20g of manganese acetate to 200ml of deionized water, stir and shake until completely dissolved; add hexadecyltrimethylammonium bromide (CTAB) in a molar ratio of 3:1 to the total amount of metal atoms to the resulting solution, stir evenly; add ammonia water to adjust the pH value of the solution to 6.5, stir evenly at room temperature, let it stand for a short time, and then hydrothermally react the solution at 180℃ for 16h; alternately use ethanol and 60℃ deionized water to wash the hydrothermal product until the impurities are completely removed; place the resulting product in a 105℃ oven to dry overnight, and then take it out and calcine it at 330℃ for 4h. Finally, grind it to 40-60 mesh to obtain a finished product, named MO.

[0053] Embodiment 1:

[0054] The present embodiment provides an ultra-low temperature manganese-based SCR denitrification catalyst (MnO2 / ZrO2 / SnO2 catalyst) and a preparation method thereof. In the catalyst, based on the total content of metal oxides as 100 mol%, the content of ZrO2 is 32 mol%, the content of SnO2 is 16 mol%, and the remainder is MnO2.

[0055] The specific implementation method includes the following steps:

[0056] Add 6.7g manganese acetate to 200ml deionized water, stir and shake until completely dissolved, add 10.2g zirconium nitrate, stir and shake repeatedly until completely dissolved, add 3.1g tin chloride, stir and shake again until completely dissolved; add hexadecyltrimethylammonium bromide (CTAB) with a molar ratio of 3:1 to the total amount of metal atoms to the obtained solution, stir evenly; add ammonia water to adjust the pH value of the solution to 6.5, stir evenly at room temperature, let it stand for a short time, and then hydrothermally react the solution at 180℃ for 16h; alternately use ethanol and 60℃ deionized water to wash the hydrothermal product until the impurities are completely removed; place the obtained product in a 105℃ oven to dry overnight, take it out and calcine it at 330℃ for 4h. Finally, grind it to 40-60 mesh to obtain the finished SCR catalyst, named 1-MZS.

[0057] Embodiment 2:

[0058] This embodiment provides an ultra-low temperature manganese-based SCR denitration catalyst (MnO2 / ZrO2 / SnO2 catalyst) and a preparation method thereof. In the catalyst, based on the total content of metal oxides as 100 mol%, the content of ZrO2 is 26 mol%, the content of SnO2 is 13 mol%, and the balance is MnO2. Except for the addition amount of each component and the corresponding addition amount of CTAB, this embodiment adopts the same preparation method and parameters as Example 1.

[0059] The specific implementation method includes the following steps:

[0060] Add 8.4g manganese acetate to 200ml deionized water, stir and shake until completely dissolved, add 8.9g zirconium nitrate and repeat stirring and shaking operation until completely dissolved, add 2.7g tin chloride and repeat stirring and shaking operation again until completely dissolved; add hexadecyltrimethylammonium bromide (CTAB) with a molar ratio of 3:1 to the total amount of metal atoms to the obtained solution, and stir evenly; add ammonia water to adjust the pH value of the solution to 6.5, and stir evenly at room temperature, let it stand for a short time, and then hydrothermally react the solution at 180℃ for 16h; alternately use ethanol and 60℃ deionized water to wash the hydrothermal product until impurities are completely removed; the obtained product is placed in a 105℃ oven to dry overnight, and then taken out and calcined at 330℃ for 4h. Finally, grind to 40-60 mesh to obtain the finished SCR catalyst, named 2-MZS.

[0061] Embodiment 3:

[0062] This embodiment provides an ultra-low temperature manganese-based SCR denitration catalyst (MnO2 / ZrO2 / SnO2 catalyst) and a preparation method thereof, wherein the catalyst contains 32 mol% ZrO2, 16 mol% SnO2, and the remainder MnO2, based on the total content of metal oxides as 100 mol%. This embodiment uses the same preparation method and parameters as in Example 1, except for the molar ratio of the amount of CTAB added to the total number of metal atoms in the solution.

[0063] The specific implementation method includes the following steps:

[0064] Add 6.7g manganese acetate to 200ml deionized water, stir and shake until completely dissolved, add 10.2g zirconium nitrate, stir and shake repeatedly until completely dissolved, add 3.1g tin chloride, stir and shake again until completely dissolved; add hexadecyltrimethylammonium bromide (CTAB) with a molar ratio of 2:1 to the total amount of metal atoms to the obtained solution, stir evenly; add ammonia water to adjust the pH value of the solution to 6.5, stir evenly at room temperature, let it stand for a short time, and then hydrothermally react the solution at 180℃ for 16h; alternately use ethanol and 60℃ deionized water to wash the hydrothermal product until the impurities are completely removed; place the obtained product in a 105℃ oven to dry overnight, take it out and calcine it at 330℃ for 4h. Finally, grind it to 40-60 mesh to obtain the finished SCR catalyst, named 3-MZS.

[0065] Embodiment 4:

[0066] This embodiment provides an ultra-low temperature manganese-based SCR denitration catalyst (MnO2 / ZrO2 / SnO2 catalyst) and a preparation method thereof. In the catalyst, based on the total content of metal oxides as 100 mol%, the content of ZrO2 is 32 mol%, the content of SnO2 is 16 mol%, and the balance is MnO2. Except for the solution pH value and the time and temperature of the hydrothermal reaction, this embodiment adopts the same preparation method and parameters as Example 1.

[0067] The specific implementation method includes the following steps:

[0068] Add 6.7g manganese acetate to 200ml deionized water, stir and shake until completely dissolved, add 10.2g zirconium nitrate, stir and shake repeatedly until completely dissolved, add 3.1g tin chloride, stir and shake again until completely dissolved; add hexadecyltrimethylammonium bromide (CTAB) with a molar ratio of 3:1 to the total amount of metal atoms to the obtained solution, stir evenly; add ammonia water to adjust the pH value of the solution to 7, stir evenly at room temperature, let it stand for a short time, and then hydrothermally react the solution at 140℃ for 12h; alternately use ethanol and 60℃ deionized water to wash the hydrothermal product until impurities are completely removed; place the obtained product in a 105℃ oven to dry overnight, take it out and calcine it at 330℃ for 4h. Finally, grind it to 40-60 mesh to obtain the finished SCR catalyst, named 4-MZS.

[0069] Embodiment 5:

[0070] This embodiment provides an ultra-low temperature manganese-based SCR denitration catalyst (MnO2 / ZrO2 / SnO2 catalyst) and a preparation method thereof. In the catalyst, based on the total content of metal oxides as 100 mol%, the content of ZrO2 is 32 mol%, the content of SnO2 is 16 mol%, and the balance is MnO2. Except for the deionized water temperature during washing and the high-temperature calcination temperature, this embodiment adopts the same preparation method and parameters as Example 1.

[0071] The specific implementation method includes the following steps:

[0072] Add 6.7g manganese acetate to 200ml deionized water, stir and shake until completely dissolved, add 10.2g zirconium nitrate, stir and shake repeatedly until completely dissolved, add 3.1g tin chloride, stir and shake again until completely dissolved; add hexadecyltrimethylammonium bromide (CTAB) with a molar ratio of 3:1 to the total amount of metal atoms to the obtained solution, stir evenly; add ammonia water to adjust the pH value of the solution to 6.5, stir evenly at room temperature, let it stand for a short time, and then hydrothermally react the solution at 180℃ for 16h; alternately use ethanol and 80℃ deionized water to wash the hydrothermal product until the impurities are completely removed; place the obtained product in a 105℃ oven to dry overnight, take it out and calcine it at 280℃ for 4h. Finally, grind it to 40-60 mesh to obtain the finished SCR catalyst, named 5-MZS.

[0073] The activity test was conducted on the catalyst MO of the comparative example and the catalysts 1-MZS, 2-MZS, 3-MZS, 4-MZS and 5-MZS of the five examples: 0.6 g of the catalyst sample was taken, the mesh size was 40-60 mesh, and placed in a quartz tube for activity test. The reaction conditions of this test example were 550 ppm NO, 550 ppm NH3, 5.6% O2, and the rest was N2. The total gas flow rate was 1 L / min, and the reaction space velocity was 100,000 h -1 The test temperatures are 60℃, 80℃, 100℃, 120℃, 140℃ and 160℃ respectively.

[0074] Activity test results such as Figure 1 As shown, the catalytic activities of the catalysts 1-MZS, 2-MZS, 3-MZS, 4-MZS and 5-MZS of the five embodiments are significantly higher than those of the catalysts of the comparative examples in a lower temperature range, among which the catalytic performance of the 1-MZS catalyst is better than that of the 2-MZS, 3-MZS, 4-MZS and 5-MZS catalysts. Under the experimental conditions, the NO conversion rate is stably maintained at more than 95% in the temperature range of 80°C to 160°C.

[0075] The stability test of the catalysts 1-MZS, 2-MZS, 3-MZS, 4-MZS and 5-MZS of the above five examples was carried out: 0.6g of catalyst sample with a mesh size of 40-60 was taken and placed in a quartz tube for activity test. The reaction conditions of this test example were 550ppm NO, 550ppm NH3, 5.6% O2, and the rest was N2. The total gas flow rate was 1L / min, and the reaction space velocity was 100,000h -1 , the test temperature is 80℃ and the time is 200h.

[0076] The stability test results are as follows Figure 2 As shown, the catalytic activities of the catalysts 1-MZS, 2-MZS, 3-MZS, 4-MZS and 5-MZS of the five embodiments are all maintained above 90%, showing stable performance.

Claims

1. An ultra-low temperature manganese-based SCR denitration catalyst, characterized in that The components of the SCR catalyst are MnO2, ZrO2 and SnO2.

2. The ultra-low temperature manganese-based SCR denitration catalyst according to claim 1, characterized in that In the SCR catalyst, based on 100 mol% of the total content of metal oxides, the content of ZrO2 is 26-32 mol%, the content of SnO2 is 13-16 mol%, and the balance is MnO2.

3. A method for preparing the ultra-low temperature manganese-based SCR denitration catalyst according to claim 2, characterized in that The method comprises the following preparation steps: Step A: preparing a mixed precursor solution of manganese, zirconium and tin; Step B: placing the precursor solution in a hydrothermal reactor for hydrothermal reaction; Step C: washing the precipitate obtained by the hydrothermal reaction; Step D: high temperature calcination; Step E: Grind the product obtained in step D to a certain mesh size to obtain a finished SCR catalyst. In the finished SCR catalyst, based on the total content of metal oxides as 100 mol%, the content of ZrO2 is 26-32 mol%, the content of SnO2 is 13-16 mol%, and the remainder is MnO2.

4. The method for preparing an ultra-low temperature manganese-based SCR denitration catalyst according to claim 3, characterized in that The specific process of step A is: adding a certain amount of manganese salt to deionized water, stirring and shaking until it is completely dissolved, adding zirconium salt after dissolution, repeatedly stirring and shaking until it is completely dissolved, adding tin salt after it is dissolved again, repeatedly stirring and shaking until it is completely dissolved, adding a certain amount of hexadecyltrimethylammonium bromide (CTAB) to the resulting solution, and stirring evenly.

5. The method for preparing an ultra-low temperature manganese-based SCR denitration catalyst according to claim 4, characterized in that The manganese salt is selected from one or more of manganese acetate, manganese nitrate, manganese chloride, and potassium permanganate; the zirconium salt is selected from one or more of zirconium acetate, zirconium nitrate, and zirconium oxychloride; the tin salt is selected from one or more of tin chloride, stannous chloride, and tin nitrate; the total concentration of metal atoms in the precursor solution is 0.37-0.40 mol / L; the molar ratio of the added amount of hexadecyltrimethylammonium bromide (CTAB) to the total amount of metal atoms in the solution is 2:1 or 3:

1.

6. The method for preparing an ultra-low temperature manganese-based SCR denitration catalyst according to claim 3, characterized in that The specific process of step B is: adding ammonia water to the precursor solution, adjusting the pH value of the solution, and stirring evenly at room temperature; after standing for a short time, placing the solution in a hydrothermal kettle for hydrothermal reaction.

7. The method for preparing an ultra-low temperature manganese-based SCR denitration catalyst according to claim 6, characterized in that The pH value of the solution is 6.5-7.0; the hydrothermal reaction temperature is 140° C.-180° C.; and the hydrothermal reaction time is 12-16 hours.

8. The method for preparing an ultra-low temperature manganese-based SCR denitration catalyst according to claim 3, characterized in that The specific process of step C is: using ethanol and deionized water at a certain temperature to alternately wash the product after the hydrothermal reaction until the impurities in the product are completely removed.

9. The method for preparing an ultra-low temperature manganese-based SCR denitration catalyst according to claim 3, characterized in that The specific process of step D is: placing the washed product in an oven to dry overnight, and then calcining it at a certain temperature for a period of time.

10. The method for preparing an ultra-low temperature manganese-based SCR denitration catalyst according to claim 9, characterized in that The calcination temperature is 280°C to 330°C, and the calcination time is 4 hours.

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