Organic ligand-modified manganese-based catalysts and their preparation methods

Abstract

This invention discloses an organic ligand-modified manganese-based catalyst and its preparation method. The preparation method of the organic ligand-modified manganese-based catalyst includes: step (1) preparing a MnO2-CeO2 catalyst precursor: weighing manganese acetate and cerium acetate as raw materials, controlling the molar ratio of Mn:Ce to be 7:3, placing manganese acetate and cerium acetate in a ball mill jar and ball milling for 30 min, then adding the organic ligand into the ball mill jar, and continuing to ball mill for another 30 min to obtain the MnO2-CeO2 catalyst precursor; step (2) preparing an organic ligand-modified manganese-based catalyst: placing the MnO2-CeO2 catalyst precursor into a muffle furnace for calcination to obtain the organic ligand-modified manganese-based catalyst. According to the preparation method of the organic ligand-modified manganese-based catalyst of this embodiment, the catalyst obtained by this preparation method has a wide reaction temperature range in the synergistic removal of nitrogen oxides and volatile organic compounds, has more active sites on the catalyst surface, and has better catalytic performance.

Description

Technical Field

[0001] This invention relates to the field of air pollution control technology, and in particular to an organic ligand-modified manganese-based catalyst and its preparation method. Background Technology

[0002] Nitrogen oxides (NOx) and volatile organic compounds (VOCs), as important precursors to PM2.5 and ozone, are major contributors to environmental problems such as haze, secondary aerosols, and photochemical smog. Selective catalytic reduction (NH3-SCR) and catalytic oxidation are among the most ideal industrial methods for reducing NOx and VOCs, respectively. However, using separation devices to remove NOx and VOCs has drawbacks such as high equipment investment, large footprint, and high operating costs. Given the current focus on multi-pollutant control, synergistically eliminating NOx and VOCs in SCR devices is a more energy-efficient and cost-effective alternative.

[0003] Mn-based catalysts are used in the production of nitrogen oxides (NOx) due to their excellent redox properties and environmental friendliness. x Mn-based catalysts show broad application prospects in the synergistic removal of volatile organic compounds (VOCs). However, traditional Mn-based catalysts still face two major problems in practical applications: firstly, NO... x There is a discrepancy between the optimal reaction temperature ranges for selective reduction and VOCs oxidation, making it difficult to achieve efficient synergistic removal within the same temperature range. Secondly, the catalyst surface has insufficient active sites and a low oxygen vacancy concentration, which limits oxygen migration and the generation of surface reactive oxygen species, resulting in poor VOCs catalytic oxidation performance. Therefore, improvements are needed. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the prior art. Therefore, one objective of the present invention is to provide a method for preparing an organic ligand-modified manganese-based catalyst, wherein the catalyst obtained by this method exhibits a wide reaction temperature range for the synergistic removal of nitrogen oxides and volatile organic compounds, has a large number of active sites on the catalyst surface, and demonstrates good catalytic performance.

[0005] The present invention also proposes an organic ligand-modified manganese-based catalyst obtained by the preparation method described above.

[0006] A method for preparing an organic ligand-modified manganese-based catalyst according to a first aspect of the present invention includes: Step (1) Preparation of MnO2-CeO2 catalyst precursor: Weigh manganese acetate and cerium acetate as raw materials, control the molar ratio of Mn:Ce to be 7:3, place the manganese acetate and cerium acetate in a ball mill jar and ball mill for 30 min, then add the organic ligand into the ball mill jar, and continue ball milling for another 30 min to obtain the MnO2-CeO2 catalyst precursor; Step (2) Preparation of organic ligand modified manganese-based catalyst: The MnO2-CeO2 catalyst precursor is placed in a muffle furnace for calcination to obtain the organic ligand modified manganese-based catalyst.

[0007] According to the method for preparing organic ligand-modified manganese-based catalysts of the present invention, by introducing organic ligands under mechanical force, organic ligands can coordinate with the precursor of Mn during ball milling, promote the regulation of the oxidation state of Mn and the formation of oxygen vacancies, improve the dispersibility and specific surface area of ​​the catalyst, increase the active sites on the catalyst surface, and enhance the catalytic performance of the organic ligand-modified manganese-based catalyst. Furthermore, by introducing organic ligands, the number and migration ability of surface active oxygen species can also be improved, resulting in high reactivity even at low temperatures, and enabling the catalyst to have a wide reaction temperature range for the synergistic removal of nitrogen oxides and volatile organic compounds.

[0008] According to some embodiments of the present invention, the organic ligand comprises ethanol or acetic acid.

[0009] According to some embodiments of the present invention, the solid-liquid ratio of the organic ligand to the mixture of manganese acetate and cerium acetate is 1:5; and / or, the concentration of the acetic acid or the ethanol is 99.99%.

[0010] According to some embodiments of the present invention, in step (1), the ball mill speed is 500 r / min, the ball milling time is 1 h, and the ball-to-material ratio is 1:7.

[0011] According to some embodiments of the present invention, the grinding jar in step (1) is a stainless steel jar, an agate jar, or a zirconium oxide jar.

[0012] According to some embodiments of the present invention, in step (2), the muffle furnace is kept open; and / or, in step (2), the calcination temperature is 250°C and the calcination time is 5h.

[0013] An organic ligand-modified manganese-based catalyst according to a second aspect of the present invention is prepared by the preparation method described in the first aspect of the present invention.

[0014] According to embodiments of the present invention, the organic ligand-modified manganese-based catalyst, prepared by the method of the first aspect of the present invention, introduces organic ligands under mechanical force. During ball milling, these ligands coordinate with the precursor of Mn, promoting the regulation of the oxidation state of Mn and the formation of oxygen vacancies, improving the dispersibility and specific surface area of ​​the catalyst, increasing the number of active sites on the catalyst surface, and enhancing the catalytic performance of the organic ligand-modified manganese-based catalyst. Furthermore, by introducing organic ligands, the number and migration ability of surface active oxygen species can be improved, resulting in high reactivity even at low temperatures. This allows the organic ligand-modified manganese-based catalyst to have a wide reaction temperature range for the synergistic removal of nitrogen oxides and volatile organic compounds.

[0015] According to some embodiments of the present invention, the organic ligand-modified manganese-based catalyst is used for the synergistic removal of NO and VOCs.

[0016] According to some embodiments of the present invention, the organic ligand-modified manganese-based catalyst is used in a catalytic reaction at a catalytic temperature of 100°C to 280°C and a space velocity of 10,000 h⁻¹. -1 ~50000 h -1 ; and / or, in the catalytic reaction, the organic ligand modified manganese-based catalyst contains O2 accounting for 1% to 10% of the total volume of the reaction atmosphere, NO concentration of 100 ppm to 1000 ppm, and VOCs concentration of 0 ppm to 200 ppm.

[0017] According to some embodiments of the present invention, the organic ligand-modified manganese-based catalyst is used for the purification of waste gas from coal-fired power plants, cement plants, and metallurgical plants.

[0018] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of a method for preparing an organic ligand-modified manganese-based catalyst according to some embodiments of the present invention; Figure 2 These are X-ray diffraction patterns of organic ligand-modified manganese-based catalysts and comparative catalysts according to some embodiments of the present invention. Figure 3 This is a comparison diagram of nitrogen adsorption-desorption isotherms of organic ligand modified manganese-based catalysts and comparative catalysts according to some embodiments of the present invention. Figure 4This is a comparison diagram of the pore size distribution curves of the organic ligand-modified manganese-based catalyst and the catalyst in the comparative example according to some embodiments of the present invention. Figure 5 This is a comparison chart of the toluene removal rates of organic ligand-modified manganese-based catalysts and comparative catalysts according to some embodiments of the present invention. Figure 6 Arrhenius diagrams of organic ligand-modified manganese-based catalysts and comparative catalysts according to some embodiments of the present invention are shown. Figure 7 This is a comparison chart of the nitrogen oxide conversion rates of organic ligand-modified manganese-based catalysts and comparative catalysts according to some embodiments of the present invention. Figure 8 This is a comparison diagram of the nitrogen selectivity of organic ligand-modified manganese-based catalysts and comparative catalysts according to some embodiments of the present invention. Figure 9 This is a comparison of O2-TPD (O2-Temperature-Programmed Desorption) curves of organic ligand-modified manganese-based catalysts and comparative catalysts according to some embodiments of the present invention. Figure 10 This is a comparison of NH3-TPD (NH3-Temperature-Programmed Desorption) curves of organic ligand-modified manganese-based catalysts and comparative catalysts according to some embodiments of the present invention. Figure 11 This is a comparison chart of H2-TPR (H2-Temperature Programmed Reduction) curves of organic ligand-modified manganese-based catalysts and comparative catalysts according to some embodiments of the present invention. Figure 12 These are XPS (X-ray Photoelectron Spectroscopy) images of organic ligand-modified manganese-based catalysts and comparative catalysts according to some embodiments of the present invention; Figure 13 These are XPS plots of organic ligand-modified manganese-based catalysts and comparative catalysts according to some embodiments of the present invention, within other binding energy ranges. Figure 14 These are XPS plots of organic ligand-modified manganese-based catalysts and comparative catalysts according to some embodiments of the present invention, within further ranges of binding energy. Detailed Implementation

[0020] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0021] The following is for reference. Figures 1-14 A method for preparing an organic ligand-modified manganese-based catalyst according to an embodiment of the present invention is described.

[0022] refer to Figure 1 The method for preparing an organic ligand-modified manganese-based catalyst according to a first aspect of the present invention includes: Step (1) Preparation of MnO2-CeO2 catalyst precursor: Weigh manganese acetate (MnC4H6O4·4H2O) and cerium acetate ((CH3CO2)3Ce·xH2O) as raw materials, control the molar ratio of Mn:Ce to be 7:3, place manganese acetate and cerium acetate in a ball mill jar and ball mill for 30 min, then add the organic ligand into the ball mill jar, and continue ball milling for another 30 min to obtain the MnO2-CeO2 catalyst precursor; by first placing manganese acetate and cerium acetate in a ball mill jar and ball milling for 30 min, then adding the organic ligand into the ball mill jar, and continuing ball milling for another 30 min, the manganese acetate and cerium acetate can be fully mixed, and then the organic ligand is fully mixed with the Mn precursor, which is conducive to the formation of MnO2-CeO2 catalyst precursor under coordination; Step (2) Preparation of organic ligand modified manganese-based catalyst: The MnO2-CeO2 catalyst precursor is placed in a muffle furnace for calcination to obtain the organic ligand modified manganese-based catalyst.

[0023] In this process, the organic ligands coordinate with the Mn and Ce precursors during mechanochemical ball milling to form an unstable metal-organic complex (i.e., the MnO2-CeO2 catalyst precursor). This complex decomposes during calcination in a muffle furnace, ultimately leaving behind a highly defective and oxygen-vacant MnO2-CeO2 catalytically active structure.

[0024] According to the method for preparing organic ligand-modified manganese-based catalysts of the present invention, by introducing organic ligands under mechanical force, organic ligands can coordinate with the precursor of Mn during ball milling, promote the regulation of the oxidation state of Mn and the formation of oxygen vacancies, improve the dispersibility and specific surface area of ​​the catalyst, increase the active sites on the catalyst surface, and enhance the catalytic performance of the organic ligand-modified manganese-based catalyst. Furthermore, by introducing organic ligands, the number and migration ability of surface active oxygen species can also be improved, resulting in high reactivity even at low temperatures, and enabling the catalyst to have a wide reaction temperature range for the synergistic removal of nitrogen oxides and volatile organic compounds.

[0025] According to some embodiments of the present invention, the organic ligand includes ethanol.

[0026] By adding ethanol, functional groups containing hydroxyl groups can be introduced to coordinate with the Mn precursor, promoting the regulation of Mn valence state and constructing high-concentration oxygen vacancies. At the same time, the catalyst dispersion and specific surface area are improved, thereby enhancing the low-temperature synergistic catalytic performance of the catalyst and achieving efficient synergistic removal of NOx reduction and VOCs oxidation within a similar temperature range.

[0027] According to some embodiments of the present invention, the organic ligand includes acetic acid.

[0028] By adding acetic acid, functional groups containing carboxyl groups can be introduced to coordinate with the Mn precursor, promoting the regulation of Mn valence state and constructing high-concentration oxygen vacancies. At the same time, the catalyst dispersion and specific surface area are improved, thereby enhancing the low-temperature synergistic catalytic performance of the catalyst and achieving efficient synergistic removal of NOx reduction and VOCs oxidation within a similar temperature range.

[0029] According to some embodiments of the present invention, the solid-liquid ratio of the organic ligand to the mixture of manganese acetate and cerium acetate is 1:5.

[0030] The solid-liquid ratio is: the solid mass of the mixture of manganese acetate and cerium acetate = the liquid volume of the organic ligand. For example, when the mixture of manganese acetate and cerium acetate is 1g, 5ml of organic ligand is added.

[0031] By making the solid-liquid ratio of the organic ligand to the mixture of manganese acetate and cerium acetate 1:5, the organic ligand can be mixed more thoroughly with the Mn precursor, which is conducive to the formation of the MnO2-CeO2 catalyst precursor under coordination and to the formation of more defects and oxygen vacancies in the MnO2-CeO2 catalytic active structure after calcination.

[0032] According to some embodiments of the present invention, the concentration of ethanol is 99.99%.

[0033] By setting the ethanol concentration to 99.99%, the ethanol can be volatilized or decomposed more quickly during calcination, reducing the residue of impurities on the organic ligand-modified manganese-based catalyst.

[0034] According to some embodiments of the present invention, the concentration of acetic acid is 99.99%.

[0035] By using acetic acid at a concentration of 99.99%, the acetic acid can be volatilized or decomposed more quickly during calcination, reducing the residue of impurities on the organic ligand-modified manganese-based catalyst.

[0036] According to some embodiments of the present invention, in step (1), the ball mill speed is 500 r / min, the ball milling time is 1 h, and the ball-to-material ratio is 1:7.

[0037] The ball-to-material ratio of 1:7 refers to the mass ratio of the grinding balls in the grinding jar to the mass of the mixture of manganese acetate and cerium acetate.

[0038] By setting the ball mill speed to 500 r / min, the ball milling time to 1 h, and the ball-to-material ratio to 1:7, manganese acetate and cerium acetate can be fully mixed. Then, the organic ligands and the Mn precursor can be fully mixed, which is beneficial for the formation of the MnO2-CeO2 catalyst precursor under coordination.

[0039] According to some embodiments of the present invention, the grinding jar in step (1) is a stainless steel jar, an agate jar, or a zirconium oxide jar.

[0040] By using a stainless steel jar, an agate jar, or a zirconia jar in step (1), where stainless steel, agate, and zirconia all have good chemical stability and high hardness, the grinding jar can have good chemical stability and structural strength, and is less likely to react chemically with manganese acetate, cerium acetate, and organic ligands, resulting in better grinding effect.

[0041] According to some embodiments of the present invention, in step (2), the muffle furnace remains open.

[0042] For example, when using a muffle stove, a gap can be left in the stove door to keep the muffle stove open.

[0043] By keeping the muffle furnace open, the oxygen concentration inside the furnace can be prevented from decreasing, allowing manganese acetate and cerium acetate to be fully oxidized to manganese oxide and cerium oxide.

[0044] According to some embodiments of the present invention, in step (2), the calcination temperature is 250°C and the calcination time is 5h.

[0045] By setting the calcination temperature to 250℃ and the calcination time to 5h, the manganese acetate and cerium acetate in the MnO2-CeO2 catalyst precursor can be oxidized and decomposed into manganese oxide and cerium oxide, and the organic ligands can be fully volatilized and decomposed, reducing the residue of impurities on the manganese-based catalyst.

[0046] According to a second aspect of the present invention, the organic ligand-modified manganese-based catalyst is prepared by the preparation method according to a first aspect of the present invention.

[0047] According to embodiments of the present invention, the organic ligand-modified manganese-based catalyst, prepared by the method of the first aspect of the present invention, introduces organic ligands under mechanical force. During ball milling, these ligands coordinate with the precursor of Mn, promoting the regulation of the oxidation state of Mn and the formation of oxygen vacancies, improving the dispersibility and specific surface area of ​​the catalyst, increasing the number of active sites on the catalyst surface, and enhancing the catalytic performance of the organic ligand-modified manganese-based catalyst. Furthermore, by introducing organic ligands, the number and migration ability of surface active oxygen species can be improved, resulting in high reactivity even at low temperatures. This allows the organic ligand-modified manganese-based catalyst to have a wide reaction temperature range for the synergistic removal of nitrogen oxides and volatile organic compounds.

[0048] According to some embodiments of the present invention, organic ligand-modified manganese-based catalysts are used for the synergistic removal of NO and VOCs.

[0049] By using organic ligand-modified manganese-based catalysts for the synergistic removal of NO and VOCs, NO in waste gas can be removed simultaneously with VOCs, thereby improving waste gas treatment efficiency and reducing waste gas treatment costs.

[0050] According to some embodiments of the present invention, the organic ligand-modified manganese-based catalyst is used in a catalytic reaction at a catalytic temperature of 100°C to 280°C and a space velocity of 10,000 h⁻¹. -1 ~50000 h -1 .

[0051] Space velocity refers to the volume of raw material passing through a unit volume of catalyst per unit time.

[0052] For example, the catalytic temperature of the catalyst can be 100℃, 120℃, 140℃, 160℃, 180℃, 200℃, 220℃, 240℃, 260℃, 280℃, etc.; the space velocity can be 10000 h⁻¹. -1 20000h -1 30000h -1 40000h -1 50000h -1 wait.

[0053] By setting the catalytic temperature to 100℃~280℃ in the catalytic reaction, a more suitable reaction temperature for nitrogen oxides and volatile organic compounds can be achieved, facilitating the synergistic removal of nitrogen oxides and volatile organic compounds; by setting the space velocity to 10000 h⁻¹... -1 ~50000 h -1 This allows for sufficient contact between nitrogen oxides and the catalyst, and between volatile organic compounds and the catalyst, resulting in more complete removal of nitrogen oxides and volatile organic compounds.

[0054] According to some embodiments of the present invention, in the catalytic reaction of the organic ligand modified manganese-based catalyst, the reaction atmosphere contains O2 accounting for 1% to 10% of the total reaction atmosphere volume, NO concentration is 100 ppm to 1000 ppm, and VOCs concentration is 0 ppm to 200 ppm.

[0055] For example, in the catalytic reaction of the organic ligand modified manganese-based catalyst, the O2 content in the reaction atmosphere can be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% of the total reaction atmosphere volume, etc.; the NO concentration can be 100 ppm, 200 ppm, 300 ppm, 400 ppm, 500 ppm, 600 ppm, 700 ppm, 800 ppm, 900 ppm, 1000 ppm, etc.

[0056] By ensuring that the O2 content in the reaction atmosphere is 1% to 10% of the total reaction atmosphere volume, the NO concentration is 100 ppm to 1000 ppm, and the VOCs concentration is 0 ppm to 200 ppm, a gaseous environment suitable for NO to undergo SCR reduction can be provided, which is beneficial for NOx removal.

[0057] According to some embodiments of the present invention, organic ligand-modified manganese-based catalysts are used for the purification of waste gases from coal-fired power plants, cement plants, and metallurgical plants. By using organic ligand-modified manganese-based catalysts for the purification of waste gases from coal-fired power plants, cement plants, and metallurgical plants, it is beneficial to utilize the volatile organic compounds (VOCs) generated from these plants, enabling the synergistic removal of VOCs and nitrogen oxides.

[0058] The following is for reference. Figures 1-14 A method for preparing an organic ligand-modified manganese-based catalyst according to some embodiments of the present invention is described.

[0059] Example 1, refer to Figure 1 In this embodiment, manganese acetate and cerium acetate with a Mn:Ce molar ratio of 7:3 were weighed and placed in a stainless steel ball mill jar. Steel balls were added until the ball-to-material ratio was 1:7. The ball mill speed was adjusted to 500 r / min, and the ball milling time was 30 min. Ethanol was added to the ball mill jar, and ball milling continued for another 30 min. After ball milling, the Mn-Ce precursor was spread evenly in a crucible and calcined in a muffle furnace at 250°C in air atmosphere for 5 h. After cooling, the sample was taken out and labeled as E-BM (ethanol).

[0060] Example 2, refer to Figure 1In this embodiment, manganese acetate and cerium acetate with a Mn:Ce molar ratio of 7:3 were weighed and placed in a stainless steel ball mill jar. Steel balls were added until the ball-to-material ratio was 1:7. The ball mill speed was adjusted to 500 r / min, and the ball milling time was 30 min. Acetic acid was added to the ball mill jar, and ball milling continued for another 30 min. After ball milling, the Mn-Ce precursor was spread evenly in a crucible and calcined in a muffle furnace at 250°C in air atmosphere for 5 h. After cooling, the sample was taken out and labeled as A-BM (acetic acid).

[0061] Comparative Example 1, In the comparative example, manganese acetate and cerium acetate with a Mn:Ce molar ratio of 7:3 were weighed and placed in a stainless steel ball mill jar. Steel balls were added to make the ball-to-material ratio 1:7. The ball mill speed was adjusted to 500 r / min, and the milling time was 1 h. After milling, the Mn-Ce precursor was spread evenly in a crucible and calcined in a muffle furnace at 250 °C in air atmosphere for 5 h. After cooling, the sample was taken out and labeled BM.

[0062] 0.2 g of the catalysts prepared in Examples 1, 2, and 1 (Comparative Example 1) were added to 0.5 ml of silica sand as experimental samples for evaluating the individual and synergistic removal performance of NO and toluene. The catalyst performance evaluation was conducted in a fixed-bed reactor at a temperature range of 100°C–280°C. Specific experimental parameters included a gas hourly space velocity (GHSV) of 24,000 h⁻¹. - ¹. The simulated flue gas consisted of 50 ppm toluene, 5 vol% O2, 400 ppm NH3, and 400 ppm NO, with N2 as the background. NO and NH3 concentrations at the fixed-bed outlet were analyzed using Fourier transform infrared spectroscopy, and toluene concentration was analyzed using gas chromatography. A NO conversion rate greater than 90% (ΔT) was used as the baseline. 90 The range of ) and the toluene conversion rate are greater than 90% (ΔT) 90 The temperature range of () was used as the evaluation standard for catalyst activity, and the results are shown in Table 1.

[0063]

[0064] Table 1 As shown in Table 1, the catalyst E-BM in Example 1 achieves a conversion rate greater than 90% in the temperature range of 157°C-238°C for the synergistic removal of nitrogen oxides and toluene. The catalyst A-BM in Example 2 achieves a conversion rate greater than 90% in the temperature range of 174°C-240°C for the synergistic removal of nitrogen oxides and toluene. The catalyst BM in Comparative Example 1 achieves a conversion rate greater than 90% in the temperature range of 190°C-248°C for the synergistic removal of nitrogen oxides and toluene. Therefore, the catalysts in this application exhibit a wide reaction temperature range for the synergistic removal of nitrogen oxides and volatile organic compounds.

[0065] To investigate the changes in surface valence state and morphology of the modified catalysts, the prepared catalysts E-BM, A-BM, and BM were characterized by X-ray diffraction, X-ray photoelectron spectroscopy (XPS), oxygen temperature-programmed desorption (O2-TPD), hydrogen temperature-programmed reduction (H2-TPR), ammonia temperature-programmed desorption (NH3-TPD), and specific surface area (BET).

[0066] Depend on Figure 2 It can be seen that the crystal phases of E-BM, A-BM and BM are α-MnO2, CeO2 and Mn3O4.

[0067] refer to Figures 3-4 ,Depend on Figure 3 It can be seen that under the same adsorption pressure, the adsorption capacity of nitrogen by E-BM and A-BM is greater than that of BM, indicating that E-BM and A-BM have higher porosity and stronger adsorption performance. Figure 4 The pore distribution of E-BM, A-BM, and BM can be determined.

[0068] refer to Figures 5-6 ,Depend on Figure 5 It can be seen that when the toluene removal rate reaches 90%, the required temperatures for both E-BM and A-BM are lower than those for BM. Figure 6 It can be seen that the activation energies of E-BM and A-BM are both lower than those of BM. Therefore, the catalytic activities of E-BM and A-BM are stronger than those of BM.

[0069] refer to Figure 9 O2-TPD characterization results showed that the oxygen in the 0~200℃ low-temperature region was physically adsorbed, the desorption peak in the 200~400℃ region was surface adsorbed oxygen species, the 400~500℃ region was surface lattice oxygen species, and the temperature above 500℃ was bulk lattice oxygen species. The E-BM catalyst had the lowest desorption peak temperatures for both surface oxygen and surface lattice oxygen, indicating that its surface active oxygen is more easily released and can participate in the toluene oxidation reaction at lower temperatures.

[0070] refer to Figure 11H2-TPR characterization results showed that all three catalysts exhibited two reduction peaks: the first peak corresponded to the reduction of MnO2 to Mn3O4, and the second peak corresponded to the reduction of Mn3O4 to MnO. After modification with acetic acid / ethanol, the reduction peak temperatures of the catalysts shifted forward overall, indicating that organic ligand modification can improve the reduction performance of Mn-based catalysts. Among them, the E-BM catalyst exhibited the best reduction performance, proving that this modified mechanochemical preparation method can effectively enhance the catalyst's reactivity.

[0071] refer to Figures 12-14 XPS analysis revealed two peaks in the O1s spectrum: the peak at 531.1–532 eV corresponds to surface chemisorbed oxygen (Oads), and the peak at 529.5 eV corresponds to lattice oxygen (Olat) from MnO2 and CeO2. Quantitative analysis showed that the E-BM catalyst had the highest Olat content, at 67.73%, higher than the A-BM catalyst (62.34%) and the BM catalyst (61.95%). This higher proportion of lattice oxygen promotes the Mars–van Krevelen mechanism in toluene oxidation, increasing oxygen migration rate and enhancing toluene decomposition efficiency.

[0072] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0073] In the description of this invention, "first feature" and "second feature" may include one or more of the features.

[0074] In the description of this invention, "a plurality of" means two or more.

[0075] In the description of this invention, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or it may include the first and second features not being in direct contact but being in contact through another feature between them.

[0076] In the description of this invention, the terms "above," "over," and "on top" for the first feature and the second feature include the first feature being directly above or diagonally above the second feature, or simply indicating that the first feature is at a higher horizontal level than the second feature.

[0077] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0078] Although embodiments of the invention have been shown and described, those skilled in the art will understand 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 claims and their equivalents.

Claims

1. A method for preparing an organic ligand-modified manganese-based catalyst, characterized in that, include: Step (1) Preparation of MnO2-CeO2 catalyst precursor: Weigh manganese acetate and cerium acetate as raw materials, control the molar ratio of Mn:Ce to be 7:3, place the manganese acetate and cerium acetate in a ball mill jar and ball mill for 30 min, then add the organic ligand into the ball mill jar, and continue ball milling for another 30 min to obtain the MnO2-CeO2 catalyst precursor; Step (2) Preparation of organic ligand modified manganese-based catalyst: The MnO2-CeO2 catalyst precursor is placed in a muffle furnace for calcination to obtain the organic ligand modified manganese-based catalyst.

2. The preparation method according to claim 1, characterized in that, The organic ligands include ethanol or acetic acid.

3. The preparation method according to claim 2, characterized in that, The solid-liquid ratio of the organic ligand to the mixture of manganese acetate and cerium acetate is 1:5; and / or the concentration of the acetic acid or the ethanol is 99.99%.

4. The preparation method according to claim 1, characterized in that, In step (1), the ball mill speed is 500 r / min, the ball milling time is 1 h, and the ball-to-material ratio is 1:

7.

5. The preparation method according to claim 1, characterized in that, The grinding jar in step (1) is a stainless steel jar, an agate jar, or a zirconia jar.

6. The preparation method according to claim 1, characterized in that, In step (2), the muffle furnace is kept open; and / or, in step (2), the calcination temperature is 250°C and the calcination time is 5 hours.

7. An organic ligand-modified manganese-based catalyst, characterized in that, The organic ligand-modified manganese-based catalyst is prepared by the preparation method according to any one of claims 1-6.

8. The organic ligand-modified manganese-based catalyst according to claim 7, characterized in that, The organic ligand-modified manganese-based catalyst is used for the synergistic removal of NO and VOCs.

9. The organic ligand-modified manganese-based catalyst according to claim 8, characterized in that, The organic ligand-modified manganese-based catalyst is used in a catalytic reaction at a temperature of 100℃~280℃ and a space velocity of 10000 h⁻¹. -1 ~50000 h -1 ; and / or, in the catalytic reaction, the organic ligand modified manganese-based catalyst contains O2 accounting for 1% to 10% of the total volume of the reaction atmosphere, NO concentration of 100 ppm to 1000 ppm, and VOCs concentration of 0 ppm to 200 ppm.

10. The organic ligand-modified manganese-based catalyst according to claim 8, characterized in that, The organic ligand-modified manganese-based catalyst is used for the purification of waste gas from coal-fired power plants, cement plants, and metallurgical plants.

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