Manganese-nickel composite oxide NH3-SCR catalyst and sol-gel preparation method thereof

Abstract

The invention belongs to the technical field of environmental catalytic materials, and particularly relates to a manganese-nickel composite oxide NH3-SCR catalyst and a sol-gel preparation method thereof. The catalyst is composed of a solid solution formed by a manganese element and a nickel element, a surface synergistic acidic system and a sulfur-resistant protective layer are formed through Ce-W-P multi-element co-modification, and the catalyst has a macropore-mesopore-micropore coexisting hierarchical pore structure. According to the preparation method of the catalyst, a sol-gel combined template method is adopted to realize multi-stage pore channel construction and multi-element modification in one step. The NOx conversion rate of the prepared catalyst in a wide temperature window of 150-350 DEG C is gt; the generation selectivity gt of N2 is 90%; the sulfur-resistant and water-resistant stability is good, and the activity retention rate gt is obtained after continuous testing for 100 h; the activity retention rate after high-temperature aging is gt; the catalyst can be applied to automobile exhaust purification and industrial flue gas denitration.

Description

Technical Field

[0001] This invention belongs to the field of environmental catalytic materials technology, specifically relating to a manganese-nickel composite oxide NH3-SCR catalyst and its sol-gel preparation method. Background Technology

[0002] Nitrogen oxides (NO) x NO is one of the major air pollutants, causing acid rain, photochemical smog, and ozone layer depletion. Ammonia selective catalytic reduction (NH3-SCR) technology is currently the most effective method for controlling NO. x The core of the control technology is the high-performance SCR catalyst. Traditional SCR catalysts are mainly divided into three categories: 1. Vanadium-based catalysts (such as V₂O₅-WO₃ / TiO₂): These are technologically mature, but have a narrow activity temperature window (300-400℃), poor low-temperature activity, and vanadium is biotoxic, posing a high environmental risk; 2. Molecular sieve catalysts (such as Cu / CHA): These have good low-temperature activity, but poor hydrothermal stability, high cost, and are difficult to apply on a large scale; 3. Metal oxide catalysts: These have advantages such as environmental friendliness and low cost, but single metal oxides often suffer from insufficient activity, narrow temperature windows, and poor sulfur and water resistance. Manganese oxide (MnO₂) is another example. x MnO has been extensively studied due to its excellent low-temperature redox properties, but pure MnO... x The following problems exist: poor N2 selectivity at high temperatures, easy formation of N2O, poor sulfur and water resistance, and insufficient thermal stability; nickel oxide (NiO) has good thermal stability and sulfur resistance, but poor low-temperature activity. How to organically combine the advantages of manganese and nickel to develop a highly active, wide-temperature-window, and highly stable SCR catalyst has become an urgent problem to be solved in this field.

[0003] In addition, traditional catalysts are mostly microporous structures, and under high temperature and high space velocity, reactants (NO, NH3) have difficulty diffusing rapidly to the active sites, resulting in a decrease in catalytic efficiency. Furthermore, the NH3-SCR reaction requires suitable acidic sites to adsorb and activate NH3, but the types and number of acidic sites on the surface of a single metal oxide are limited, which restricts the reaction rate. Finally, SO2 and H2O will compete for adsorption on the active sites, leading to catalyst poisoning and deactivation. Summary of the Invention

[0004] The present invention aims to overcome the shortcomings of the prior art and provide a highly active, wide temperature window, and highly stable manganese-nickel composite oxide NH3-SCR catalyst. Furthermore, the present invention aims to solve the problems of mass transfer limitation, insufficient acid sites, and poor resistance to poisoning of traditional catalysts through innovative material design and preparation process.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A manganese-nickel composite oxide NH3-SCR catalyst, comprising manganese oxide, nickel oxide, and an additive; The manganese oxide and nickel oxide are Mn x Ni 1-x It exists in the form of a solid solution; The additives include cerium oxide and tungsten oxide; The catalyst surface contains metal phosphate species; The catalyst has a multi-level pore structure with macropores, mesopores and micropores coexisting. The molar ratio of manganese in the manganese oxide to nickel in the nickel oxide is (2.7-4):(0.81-1.19).

[0006] Preferably, the pore size of the macropores is 50-500 nm, the pore size of the mesopores is 2-50 nm, and the pore size of the micropores is <2 nm.

[0007] Preferably, the macropores provide rapid mass transfer channels, the mesopores provide high specific surface area, and the micropores provide abundant active sites.

[0008] Preferably, the catalyst surface is co-modified with the rare earth element cerium (Ce) and the transition metal element tungsten (W) to construct a synergistic acidic system of Bronsted acid sites and Lewis acid sites.

[0009] Preferably, the metal phosphate species form a stable phosphate protective layer on the catalyst surface to inhibit SO2 adsorption and sulfation.

[0010] Preferably, the additive may further include oxides of the rare earth element lanthanum (La) and oxides of the transition metal element molybdenum (Mo).

[0011] Preferably, the Mn x Ni 1-x In the O solid solution, x = 0.77.

[0012] Preferably, the molar ratio of manganese in the manganese oxide to nickel in the nickel oxide is 2.7:0.81, that is, the molar ratio of manganese to nickel is 0.77:0.23.

[0013] Preferably, the molar ratio of manganese in the manganese oxide to nickel in the nickel oxide is 4:1.19, that is, the molar ratio of manganese to nickel is 0.77:0.23.

[0014] Preferably, the molar ratio of manganese in the manganese oxide to nickel in the nickel oxide is 3.35:1.

[0015] The present invention also discloses a method for preparing the manganese-nickel composite oxide NH3-SCR catalyst as described above, including the sol-gel method; The sol-gel preparation method of the manganese-nickel composite oxide NH3-SCR catalyst includes the following steps: Step (1): Dissolve soluble manganese salt, soluble nickel salt, soluble rare earth salt, soluble transition metal salt, and soluble phosphate in deionized water to prepare a precursor solution; The complexing agent is dissolved in deionized water to prepare a complexing agent solution; Step (2): Mix the precursor solution and complexing agent solution, add template material, and heat and stir to form a sol; Step (3): Let the sol stand to form a gel; Step (4): The gel is dried and calcined to obtain the manganese-nickel composite oxide NH3-SCR catalyst.

[0016] Preferably, in step (1), the molar ratio of soluble manganese salt, soluble nickel salt, soluble rare earth salt, soluble transition metal salt, soluble phosphate, and complexing agent is (2.7-4):(0.81-1.19):(0.4-0.6):(0.1-0.3):(0.3-0.5):(10-20). When preparing the precursor solution, the amount of deionized water is 3-7 times the sum of the masses of soluble manganese salt, soluble nickel salt, soluble rare earth salt, soluble transition metal salt, and soluble phosphate. When preparing the complexing agent solution, the amount of deionized water is 2-4 times the mass of the complexing agent.

[0017] Preferably, the soluble manganese salt includes manganese nitrate; The soluble nickel salt includes nickel nitrate; The soluble rare earth salts include cerium nitrate; The soluble transition metal salts include ammonium metatungstate hydrate; The soluble phosphate includes ammonium dihydrogen phosphate; The complexing agent includes a composite complexing agent composed of citric acid and ethylene glycol; In the composite complexing agent, the molar ratio of citric acid to ethylene glycol is 1:(1-2).

[0018] Preferably, in step (2), the template material includes macroporous template material and mesoporous template material, and the heating and stirring conditions are stirring at 60-80℃ for 2-3 hours.

[0019] Preferably, the amount of macroporous template material added is 0.8%-1.2% of the total mass of the precursor solution and the complexing agent solution, and the amount of mesoporous template material added is 0.3%-0.7% of the total mass of the precursor solution and the complexing agent solution. The macroporous template material includes polystyrene microspheres, and the mesoporous template material includes P123 block copolymer (polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer).

[0020] Preferably, the polystyrene microspheres have a particle size of 200-400 nm.

[0021] Preferably, in step (3), the standing condition is to stand at room temperature for 24-48 hours.

[0022] Preferably, in step (4), the calcination is a programmed temperature calcination, and the programmed temperature calcination process includes: First, bake at 250-300℃ for 1.5-2.5 hours to remove the template material and form channels; Then calcine at 400-500℃ for 2.5-3.5 hours to form a solid solution structure; Finally, it is calcined at 550-600℃ for 1-2 hours to form a surface modified layer.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows: In this invention, during the preparation of the catalyst, a manganese-nickel solid solution is constructed, and the solid solution contains Mn 2+ / Mn 3+ and Ni 2+ The electronic interactions enhance the redox cycle capability, achieving an atomic-level synergy between the high and low temperature activity of manganese and the thermal stability and sulfur resistance of nickel. This results in a catalyst with wide-temperature range, high activity, and high selectivity, exhibiting NO reduction across the entire temperature range of 150-350℃. x The conversion rates all exceeded 90%, and the N2 generation selectivity was all above 95%. Furthermore, by introducing the rare earth element Ce, its Ce... 4+ / Ce 3+ The unique oxygen storage capacity of the redox cycle significantly promotes NO production at low temperatures. x The reduction reaction has achieved a synergistic breakthrough in terms of low-temperature activity and high-temperature stability, fundamentally overcoming the industry bottlenecks of narrow activity window (300-400℃) and insufficient low-temperature activity of single metal oxides in traditional vanadium-based catalysts. In this invention, by introducing a metal phosphate protective layer formed by P element, the adsorption and sulfation of SO2 at the active site are effectively suppressed. Furthermore, by utilizing the co-modification of Ce and W elements, the surface acidity and redox properties are adjusted, thereby synergistically improving the catalyst's water resistance and sulfur resistance. The catalyst in this invention has excellent high-temperature stability and anti-aging properties. The hierarchical pore structure and manganese-nickel solid solution form a stable framework, which effectively prevents the sintering and aggregation of active components at high temperatures. The Ce, W and P multi-component modification not only improves the catalytic activity, but also further enhances the structural stability of the catalyst by forming stable tungstate and phosphate surface species. In this invention, a multi-level pore structure with macropores, mesopores, and micropores coexisting is constructed by the template method, which realizes the rapid diffusion of reactants NO and NH3 and the timely desorption of products. The multi-level pore structure provides a huge specific surface area and abundant active sites, ensuring sufficient contact between reactants and active sites, and solving the problem of efficiency reduction caused by mass transfer limitations in traditional microporous catalysts. Attached Figure Description

[0024] Figure 1 This is a SEM image of the catalyst sample prepared in Comparative Example 1 of the present invention. Figure 2 The catalyst sample (Mn) prepared in Comparative Example 1 of the present invention 0.77 Ni 0.23 XRD pattern of O); Figure 3 The catalyst samples prepared in Examples 1-8 of this invention showed NO levels in the catalytic activity test. x Graph showing the results of the conversion rate measurement; Figure 4 The graph shows the N2 generation selectivity of the catalyst samples prepared in Examples 1-8 of the present invention in the catalytic activity test. Figure 5 The graph shows the results of the activity retention rate of the catalyst samples prepared in Examples 1-8 of the present invention in the sulfur and water resistance stability test; Figure 6 The graph shows the results of the activity retention rate determination of the catalyst samples prepared in Examples 1-8 of the present invention in the high-temperature aging performance test. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0026] Example 1: This example discloses a sol-gel preparation method for a manganese-nickel composite oxide NH3-SCR catalyst, including the following steps: Step (1): Dissolve 50wt% manganese nitrate aqueous solution, nickel nitrate hexahydrate, cerium nitrate hexahydrate, ammonium metatungstate hydrate, and ammonium dihydrogen phosphate in deionized water. The amount of deionized water is 7 times the total mass of 50wt% manganese nitrate aqueous solution, nickel nitrate hexahydrate, cerium nitrate hexahydrate, ammonium metatungstate hydrate, and ammonium dihydrogen phosphate to prepare a precursor solution. Citric acid and ethylene glycol are dissolved in deionized water, with the amount of deionized water being 4 times the combined mass of citric acid and ethylene glycol, to prepare a complexing agent solution. The molar ratio of 50wt% manganese nitrate aqueous solution, nickel nitrate hexahydrate, cerium nitrate hexahydrate, ammonium metatungstate hydrate, ammonium dihydrogen phosphate, citric acid and ethylene glycol is 2.7:0.81:0.4:0.1:0.3:5:5. Step (2): Mix the precursor solution and the complexing agent solution, add polystyrene microspheres and P123 block copolymer. The amount of polystyrene microspheres added is 0.8% of the total mass of the precursor solution and the complexing agent solution, and the amount of P123 block copolymer added is 0.3% of the total mass of the precursor solution and the complexing agent solution. Add 0.5 mol / L nitric acid solution to adjust the pH of the reaction mixture to 2.5. Stir at 60℃ for 3 hours to form a sol. Step (3): Let the sol stand at room temperature for 24 hours to form a gel; Step (4): After drying the gel at 100℃ for 24h, it is calcined to obtain the manganese-nickel composite oxide NH3-SCR catalyst. The calcination is a programmed temperature calcination, and the programmed temperature calcination process includes: First, it is calcined at 250℃ for 2.5 hours to remove the template material and form channels. Then, it is calcined at 400℃ for 3.5 hours to form a solid solution structure. Finally, it is calcined at 550℃ for 2 hours to form a surface modified layer.

[0027] Example 2: This example discloses a sol-gel preparation method for a manganese-nickel composite oxide NH3-SCR catalyst, including the following steps: Step (1): Dissolve 50wt% manganese nitrate aqueous solution, nickel nitrate hexahydrate, cerium nitrate hexahydrate, ammonium metatungstate hydrate, and ammonium dihydrogen phosphate in deionized water. The amount of deionized water is 3 times the total mass of 50wt% manganese nitrate aqueous solution, nickel nitrate hexahydrate, cerium nitrate hexahydrate, ammonium metatungstate hydrate, and ammonium dihydrogen phosphate to prepare a precursor solution. Dissolve citric acid and ethylene glycol in deionized water, using twice the total mass of citric acid and ethylene glycol, to prepare a complexing agent solution. The molar ratio of 50wt% manganese nitrate aqueous solution, nickel nitrate hexahydrate, cerium nitrate hexahydrate, ammonium metatungstate hydrate, ammonium dihydrogen phosphate, citric acid and ethylene glycol is 4:1.19:0.6:0.3:0.5:10:10. Step (2): Mix the precursor solution and the complexing agent solution, add polystyrene microspheres and P123 block copolymer. The amount of polystyrene microspheres added is 1.2% of the total mass of the precursor solution and the complexing agent solution, and the amount of P123 block copolymer added is 0.7% of the total mass of the precursor solution and the complexing agent solution. Add 0.5 mol / L nitric acid solution to adjust the pH of the reaction mixture to 2.5. Stir at 80℃ for 2 hours to form a sol. Step (3): Let the sol stand at room temperature for 48 hours to form a gel; Step (4): After drying the gel at 100℃ for 24h, it is calcined to obtain the manganese-nickel composite oxide NH3-SCR catalyst. The calcination is a programmed temperature calcination, and the programmed temperature calcination process includes: First, it is calcined at 300℃ for 1.5 hours to remove the template material and form channels. Then, it is calcined at 500℃ for 2.5 hours to form a solid solution structure. Finally, it is calcined at 600℃ for 1 hour to form a surface modification layer.

[0028] Example 3: This example discloses a sol-gel preparation method for a manganese-nickel composite oxide NH3-SCR catalyst, including the following steps: Step (1): Dissolve 50wt% manganese nitrate aqueous solution, nickel nitrate hexahydrate, cerium nitrate hexahydrate, ammonium metatungstate hydrate, and ammonium dihydrogen phosphate in deionized water. The amount of deionized water is 5 times the total mass of 50wt% manganese nitrate aqueous solution, nickel nitrate hexahydrate, cerium nitrate hexahydrate, ammonium metatungstate hydrate, and ammonium dihydrogen phosphate to prepare a precursor solution. Dissolve citric acid and ethylene glycol in deionized water, with the amount of deionized water being three times the combined mass of citric acid and ethylene glycol, to prepare a complexing agent solution. The molar ratio of 50wt% manganese nitrate aqueous solution, nickel nitrate hexahydrate, cerium nitrate hexahydrate, ammonium metatungstate hydrate, ammonium dihydrogen phosphate, citric acid and ethylene glycol is 3.35:1:0.5:0.2:0.4:5:10. Step (2): Mix the precursor solution and the complexing agent solution, add polystyrene microspheres and P123 block copolymer. The amount of polystyrene microspheres added is 1% of the total mass of the precursor solution and the complexing agent solution, and the amount of P123 block copolymer added is 0.5% of the total mass of the precursor solution and the complexing agent solution. Add 0.5 mol / L nitric acid solution to adjust the pH of the reaction mixture to 2.5. Stir at 70°C for 2.5 h to form a sol. Step (3): Let the sol stand at room temperature for 36 hours to form a gel; Step (4): After drying the gel at 100℃ for 24h, it is calcined to obtain the manganese-nickel composite oxide NH3-SCR catalyst. The calcination is a programmed temperature calcination, and the programmed temperature calcination process includes: First, it is calcined at 280℃ for 2 hours to remove the template material and form channels. Then, it is calcined at 450℃ for 2 hours to form a solid solution structure. Finally, it is calcined at 580℃ for 1.5 hours to form a surface modification layer.

[0029] Comparative Example 1: Compared with Example 3, the only difference in the preparation of the manganese-nickel composite oxide NH3-SCR catalyst in Comparative Example 1 is that cerium nitrate hexahydrate, ammonium metatungstate hydrate, and ammonium dihydrogen phosphate were not added.

[0030] Comparative Example 2: Compared with Example 3, the only difference in the preparation of the manganese-nickel composite oxide NH3-SCR catalyst in Comparative Example 2 is that cerium nitrate hexahydrate was not added.

[0031] Comparative Example 3: Compared with Example 3, the only difference in the preparation of the manganese-nickel composite oxide NH3-SCR catalyst in Comparative Example 3 is that ammonium metatungstate hydrate was not added.

[0032] Comparative Example 4: Compared with Example 3, the only difference in the preparation of the manganese-nickel composite oxide NH3-SCR catalyst in Comparative Example 4 is that ammonium dihydrogen phosphate was not added.

[0033] Comparative Example 5: Compared with Example 3, the only difference in the preparation of the manganese-nickel composite oxide NH3-SCR catalyst in Comparative Example 5 is that the template material polystyrene microspheres and P123 block copolymer were not added.

[0034] In the above examples and comparative examples, the particle size of the polystyrene microspheres was 300 nm; the molecular weight of the ammonium metatungstate hydrate was 2956.30.

[0035] Experimental Example: Performance tests were conducted on the manganese-nickel composite oxide NH3-SCR catalyst samples prepared in Examples 1-3 and Comparative Examples 1-5: Test (1) Catalytic activity test: The catalyst sample was placed in a tubular fixed-bed reactor with an inner diameter of 8 mm. The particle size of the catalyst sample was 40-60 mesh, and the loading amount of the catalyst sample was 0.5 g. The composition of the reaction gas was: 950 ppm NO, 50 ppm NO2, 1000 ppm NH3, 5% O2, the equilibrium gas was N2, and the space velocity was 50000 h⁻¹. -1 The reaction temperature range is 150-350℃, and NO is measured. x Conversion rate and N2 generation selectivity (considering only N2O as the main byproduct).

[0036] NO x The formula for calculating conversion rate is as follows: ×100% (1); In the formula: [NO x [in] represents NO at the reactor inlet. x Concentration (ppm); [NO x ]out represents NO at the reactor outlet x Concentration (ppm); The formula for calculating the selectivity of N2 generation is as follows: ×100% (2); In the formula: [NO x [in] represents NO at the reactor inlet. x Concentration (ppm); [NO x ]out represents NO at the reactor outlet x Concentration (ppm); [N2O]out is the N2O concentration (ppm) at the reactor outlet. NO x The results of the conversion rate and N2 generation selectivity are shown in Table 1: Table 1

[0037] As shown in Table 1, the manganese-nickel composite oxide NH3-SCR catalyst prepared in this invention exhibits excellent catalytic activity. Within a wide temperature window of 150-350℃, the NOx conversion rate is >90%, and the N2 formation selectivity is >95%. Compared to Example 3, in Comparative Examples 1 and 2, no rare earth element Ce was introduced during catalyst preparation, resulting in a significant decrease in NOx conversion rate at 150℃. This indicates that Ce's oxygen storage capacity (Ce... 4+ / Ce 3+The redox cycle effectively promoted the reduction of NOx at low temperatures, significantly improving low-temperature activity. In Comparative Example 3, the absence of the transition metal element W during catalyst preparation led to a decrease in activity at medium and low temperatures, and a reduction in N2 generation selectivity. This indicates that W increased surface bronsted acid sites, promoting the adsorption and activation of NH3. In Comparative Example 4, the absence of P during catalyst preparation resulted in an N2 generation selectivity of 88.7% at 350℃, which was lower than that of Example 3, indicating that P plays a positive role in improving the high-temperature N2 generation selectivity. In Comparative Example 5, the absence of a template material during catalyst preparation led to an underdeveloped pore structure and a general decrease in activity, indicating that the hierarchical pore structure effectively improved the mass transfer efficiency of the reactants.

[0038] Test (2) Sulfur and water resistance stability test: At 250℃, 100ppm SO2 and 10% H2O were introduced into the reaction gas through a saturator, and the test was conducted continuously for 100h. Based on the initial NO x Conversion rate and NO after 100 hours of testing x The conversion rate is used to calculate the activity retention rate. The higher the activity retention rate, the better the sulfur and water resistance.

[0039] The formula for calculating the activity retention rate is as follows: ×100% (3); The results of the activity retention rate determination are shown in Table 2: Table 2

[0040] As shown in Table 2, the manganese-nickel composite oxide NH3-SCR catalyst prepared in this invention exhibits good sulfur and water resistance. Compared with Example 3, in Comparative Examples 1 and 2, no rare earth element Ce was introduced during catalyst preparation; in Comparative Example 3, no transition metal element W was introduced. The activity retention rates were significantly reduced, indicating that Ce and W synergistically improved the catalyst's water and sulfur resistance by adjusting surface acidity and redox properties. In Comparative Example 4, no P was introduced during catalyst preparation, resulting in a substantial decrease in activity retention rate, indicating that the phosphate protective layer is key to resisting SO2 poisoning and effectively inhibits sulfate formation and deposition. In Comparative Example 5, no template material was introduced during catalyst preparation, also leading to a decrease in activity retention rate, indicating that hierarchical channels facilitate the diffusion of reactants and products, reducing the risk of sulfate clogging active sites.

[0041] Test (3) High-temperature aging resistance test: After the catalyst was treated in an air atmosphere at 800℃ for 10h, the NO content of the catalyst was measured at 250℃ according to the method in test (1). xConversion rate, and NO at 250°C in test (1) x Conversion rate as NO before aging x The conversion rate was calculated, and the activity retention rate after aging was determined. The results of the activity retention rate measurement are shown in Table 3. Table 3

[0042] As shown in Table 3, the manganese-nickel composite oxide NH3-SCR catalyst prepared in this invention exhibits excellent resistance to high-temperature aging. Compared with Example 3, in Comparative Examples 1 and 2, no rare earth element Ce was introduced during catalyst preparation; in Comparative Example 3, no transition metal element W was introduced during catalyst preparation. The activity retention rates were significantly reduced in both cases, indicating that the introduction of Ce and W enhanced the structural stability and anti-sintering ability of the catalyst. In Comparative Example 4, no P element was introduced during catalyst preparation, and the activity retention rate was also reduced, indicating that P element further improved the structural stability at high temperatures by forming stable phosphate species. In Comparative Example 5, no template material was introduced during catalyst preparation, resulting in the lowest activity retention rate, indicating that the hierarchical pore and solid solution structure provided a stable framework, preventing particle aggregation at high temperatures.

[0043] 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 manganese-nickel composite oxide NH3-SCR catalyst, characterized in that, Includes manganese oxides, nickel oxides, and additives; The manganese oxide and nickel oxide are Mn x Ni 1-x It exists in the form of a solid solution; The additives include cerium oxide and tungsten oxide; The catalyst surface contains metal phosphate species; The catalyst has a multi-level pore structure with macropores, mesopores and micropores coexisting. The molar ratio of manganese in the manganese oxide to nickel in the nickel oxide is (2.7-4):(0.81-1.19).

2. The manganese-nickel composite oxide NH3-SCR catalyst according to claim 1, characterized in that, The Mn x Ni 1-x In the O solid solution, x = 0.

77.

3. The manganese-nickel composite oxide NH3-SCR catalyst according to claim 1, characterized in that, The molar ratio of manganese in the manganese oxide to nickel in the nickel oxide is 2.7:0.

81.

4. The manganese-nickel composite oxide NH3-SCR catalyst according to claim 1, characterized in that, The molar ratio of manganese in the manganese oxide to nickel in the nickel oxide is 4:1.

19.

5. The manganese-nickel composite oxide NH3-SCR catalyst according to claim 1, characterized in that, The molar ratio of manganese in the manganese oxide to nickel in the nickel oxide is 3.35:

1.

6. A method for preparing the manganese-nickel composite oxide NH3-SCR catalyst as described in any one of claims 1-5, characterized in that, Including the sol-gel method; The sol-gel preparation method of the manganese-nickel composite oxide NH3-SCR catalyst includes the following steps: Step (1): Dissolve soluble manganese salt, soluble nickel salt, soluble rare earth salt, soluble transition metal salt, and soluble phosphate in deionized water to prepare a precursor solution; The complexing agent is dissolved in deionized water to prepare a complexing agent solution; Step (2): Mix the precursor solution and complexing agent solution, add template material, heat and stir to form a sol; Step (3): Let the sol stand to form a gel; Step (4): The gel is dried and calcined to obtain the manganese-nickel composite oxide NH3-SCR catalyst.

7. The sol-gel preparation method of the manganese-nickel composite oxide NH3-SCR catalyst according to claim 6, characterized in that, In step (1), the molar ratio of soluble manganese salt, soluble nickel salt, soluble rare earth salt, soluble transition metal salt, soluble phosphate, and complexing agent is (2.7-4):(0.81-1.19):(0.4-0.6):(0.1-0.3):(0.3-0.5):(10-20); The soluble manganese salt includes manganese nitrate; The soluble nickel salt includes nickel nitrate; The soluble rare earth salts include cerium nitrate; The soluble transition metal salts include ammonium metatungstate hydrate; The soluble phosphate includes ammonium dihydrogen phosphate; The complexing agent includes a composite complexing agent composed of citric acid and ethylene glycol; In the composite complexing agent, the molar ratio of citric acid to ethylene glycol is 1:(1-2).

8. The sol-gel preparation method of the manganese-nickel composite oxide NH3-SCR catalyst according to claim 6, characterized in that, In step (2), the template material includes macroporous template material and mesoporous template material, and the heating and stirring conditions are stirring at 60-80℃ for 2-3 hours; The amount of macroporous template material added is 0.8%-1.2% of the total mass of the precursor solution and the complexing agent solution, and the amount of mesoporous template material added is 0.3%-0.7% of the total mass of the precursor solution and the complexing agent solution. The macroporous template material includes polystyrene microspheres, and the mesoporous template material includes P123 block copolymer.

9. The sol-gel preparation method of the manganese-nickel composite oxide NH3-SCR catalyst according to claim 6, characterized in that, In step (3), the standing condition is to stand at room temperature for 24-48 hours.

10. The sol-gel preparation method of the manganese-nickel composite oxide NH3-SCR catalyst according to claim 4, characterized in that, In step (4), the calcination is a programmed temperature calcination, and the programmed temperature calcination process includes: First, calcine at 250-300℃ for 1.5-2.5 hours; Then calcine at 400-500℃ for 2.5-3.5 hours; Finally, calcine at 550-600℃ for 1-2 hours.

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