A manganese-based catalyst for the simultaneous removal of NO x and CO, its preparation method and use

Abstract

This invention provides a method for NO x Manganese-based catalysts for the synergistic removal of NO and CO, their preparation methods, and applications are disclosed. The manganese-based catalyst comprises manganese dioxide of the naphthoic mineral type and alkaline earth metal elements and copper doped into the naphthoic mineral type manganese dioxide. This invention provides a manganese dioxide-based catalyst doped with alkaline earth metals and copper (Cu), which exhibits excellent resistance to alkali metal / alkaline earth metal poisoning and can achieve NO removal under mild conditions. x It exhibits good catalytic performance and long-term stability in synergistic removal of CO.

Description

Technical Field

[0001] This invention belongs to the field of industrial flue gas purification technology, and relates to a method for NO purification. x Manganese-based catalysts for the synergistic removal of CO and their preparation methods and applications. Background Technology

[0002] Steelmaking, coking, sintering, boilers, and other fossil fuel combustion processes typically emit large amounts of industrial flue gas, including carbon monoxide (CO) and nitrogen oxides (NOx). x CO and NO are two representative types of gaseous pollutants. CO is highly toxic; after entering the human body, it preferentially binds to hemoglobin, weakening the blood's oxygen-carrying capacity and leading to tissue hypoxia, which can even be life-threatening in severe cases. x This not only irritates and damages the respiratory system, but also participates in secondary pollution processes such as photochemical smog and acid deposition, adversely affecting both human health and the ecological environment. In recent years, NO... x With increasingly stringent emission control requirements for CO, NO... x Research on the purification and removal of CO is very important.

[0003] Among existing waste gas treatment technologies, the combination of NH3 selective catalytic reduction (NH3-SCR) and CO oxidation is considered to achieve the treatment of CO and NO. x An effective purification approach. In the NH3-SCR synergistic CO oxidation reaction, the appropriate selection of the catalyst has a decisive influence on its catalytic activity. Among existing catalyst systems, noble metal-based catalysts can be used for catalytic removal, although noble metal-based catalysts have limitations in removing NO. x While exhibiting good performance in CO removal, its high cost and narrow temperature range limit its practical application. Transition metal oxide catalysts (Fe, Cu, Mn, etc.) have attracted much attention due to their low cost and high activity. Among them, Mn-based oxides have shown excellent low-temperature denitrification performance due to their multiple valence states and excellent oxygen storage capacity. However, single Mn-based oxides are difficult to achieve NO removal at low temperatures. x Synergistic removal with CO.

[0004] Therefore, developing a Mn-based oxide catalyst material with controllable composition, stable structure, simple preparation process, and excellent synergistic catalytic performance has important theoretical significance and application value. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a method for NO xManganese-based catalysts for the synergistic removal of NO and CO, their preparation methods, and applications. This invention provides a manganese dioxide-based catalyst doped with alkaline earth metals and copper (Cu). This catalyst exhibits excellent resistance to alkali metal / alkaline earth metal poisoning and can achieve NO removal under mild conditions. x It exhibits good catalytic performance and long-term stability in synergistic removal of CO.

[0006] To achieve this objective, the present invention employs the following technical solution:

[0007] In a first aspect, the present invention provides a method for NO x A manganese-based catalyst for the synergistic removal of CO, wherein the manganese-based catalyst comprises manganese dioxide of naphthoic mineral type and alkaline earth metal elements and copper elements doped in the naphthoic mineral type manganese dioxide.

[0008] Preferably, the alkaline earth metal element includes calcium and / or magnesium, with calcium being the most preferred.

[0009] Preferably, the alkaline earth metal element is doped into the interlayer of manganese dioxide in the form of intercalation ions;

[0010] Preferably, the copper element is doped into manganese dioxide of the sodium manganese oxide type by means of lattice doping.

[0011] Secondly, the present invention provides a method for NO as described in the first aspect. x A method for preparing a manganese-based catalyst for the synergistic removal of CO, the method comprising the following steps:

[0012] A precipitation reaction is carried out using a mixture of manganese source, alkaline earth metal source, copper source, oxidant, precipitant and solvent to obtain a precursor;

[0013] The precursor is calcined to obtain the product used for NO. x Manganese-based catalysts for the synergistic removal of CO.

[0014] Preferably, the manganese source includes any one or a combination of at least two of manganese sulfate, manganese nitrate, or manganese acetate, with manganese acetate being the most preferred.

[0015] Preferably, the copper source includes copper nitrate and / or copper sulfate, with copper nitrate being the most preferred.

[0016] Preferably, in the preparation process, the molar ratio of the total molar amount of manganese, the molar amount of alkaline earth metals and the molar amount of copper is 1:(0.125~0.5):(0.05~0.5), more preferably 1:0.5 (0.05~0.5).

[0017] Preferably, the precipitant comprises an alkali.

[0018] Preferably, the oxidant includes potassium permanganate and / or hydrogen peroxide.

[0019] Preferably, the pH value of the precipitation reaction is 11-13.

[0020] Preferably, the precipitation reaction takes 0.5 h to 3 h.

[0021] Preferably, after the precipitation reaction, the sample is washed with water and dried to obtain the precursor.

[0022] Preferably, the heating rate of the calcination treatment is 1℃ / min to 3℃ / min, the calcination temperature is 400℃ to 600℃, and the calcination time is 2h to 5h.

[0023] Thirdly, the present invention also provides an application of a manganese-based catalyst, the application comprising using the manganese-based catalyst as described in the first aspect or the manganese-based catalyst as described in the second aspect for NO. x Synergistic removal with CO.

[0024] Preferably, the NO x Co-removal methods with CO include:

[0025] Under the catalytic action of manganese-based catalysts, NH3-SCR and CO oxidation are synergistically catalyzed to produce NO. x And CO.

[0026] Preferably, the reaction temperature for the catalysis is 30°C to 275°C.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] It is difficult to achieve NO at low temperatures using single Mn-based oxides. x To address the issue of synergistic removal of CO, this invention provides a manganese-based catalyst. This catalyst involves co-doping alkaline earth metals and copper in manganese dioxide (manganese dioxide) with sodium manganese hydrate, resulting in a synergistic effect that resists alkali metal / alkaline earth metal (alkali metal and / or alkaline earth metal) poisoning. It can also exhibit high NO removal efficiency under mild conditions. x It exhibits good catalytic performance and long-term stability, and is suitable for industrial flue gas treatment systems, which has significant theoretical and practical value. Attached Figure Description

[0029] Figure 1 The images show the XRD patterns of the manganese-based catalysts provided in Examples 1-4 and Comparative Example 1 of this invention.

[0030] Figure 2 The images show TEM images of the manganese-based catalysts provided in Example 2 and Comparative Example 1 of this invention.

[0031] Figure 3 The graph shows the performance test results of the manganese-based catalysts provided in Examples 1-4 and Comparative Examples 1-2 for CO catalytic oxidation in NH3-SCR synergistic CO oxidation.

[0032] Figure 4 The manganese-based catalysts provided in Examples 1-4 and Comparative Examples 1-2 are used for the co-oxidation of NO in NH3-SCR with CO. x Performance test chart for catalysis.

[0033] Figure 5 Performance test diagrams of the manganese-based catalysts provided in Examples 2, 2-1, 2-2, and 2-3 for CO catalytic oxidation in NH3-SCR synergistic CO oxidation.

[0034] Figure 6 The manganese-based catalysts provided in Examples 2, 2-1, 2-2, and 2-3 are used for the co-oxidation of NO in NH3-SCR with CO. x Performance test chart for catalysis. Detailed Implementation

[0035] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0036] The "range" disclosed in this invention can be defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the specific range. This type of range definition can include or exclude endpoints; any endpoint can be independently included or excluded, and they can be arbitrarily combined, meaning any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for specific parameters, it is understood that ranges of 60~110 and 80~120 are also expected. Furthermore, if minimum range values ​​1 and 2 are listed, and maximum range values ​​3, 4, and 5 are also listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this invention, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0" and "5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is described as an integer ≥2, it is equivalent to listing integers such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. For instance, when a parameter is described as an integer selected from "2~10", it is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0037] In this invention, "a combination of at least two" refers to a quantity greater than or equal to two, unless otherwise specified. For example, "any combination of one or at least two" means one or more or more items. It can be understood that when referring to "a combination of at least two," it refers to any suitable combination of multiple items, that is, a combination of "at least two" items carried out in a manner that does not conflict with and enables the implementation of this invention.

[0038] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions.

[0039] The term "embodiment" as used in this invention means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this invention can be combined with other embodiments.

[0040] In this invention, open-ended technical features or solutions described using terms such as "comprising" do not exclude additional members beyond those listed unless otherwise specified. They can be considered as providing both closed-ended features or solutions comprised of the listed members and open-ended features or solutions that include additional members beyond the listed members. For example, A includes a1, a2, and a3. Unless otherwise specified, it may also include other members or exclude additional members. This can be considered as providing both technical features or solutions where "A is composed of a1, a2, and a3" or "A is selected from a1, a2, and a3," and technical features or solutions where "A includes not only a1, a2, and a3, but also other members."

[0041] In this invention, unless otherwise specified, the features or solutions corresponding to "and / or" include any one of two or more of the related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "A and / or B" represents a group consisting of A, B, and "a combination of A and B". "Containing A and / or B" can mean "containing A, containing B, and containing A and B", or "containing A, containing B, or containing A and B", and can be appropriately understood according to the context.

[0042] In this invention, the terms "first aspect," "second aspect," "third aspect," "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," "fourth," etc., serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on the quantity.

[0043] In this invention, "optional" means that something is optional, that is, it refers to either "with" or "without". If there are multiple "optional" options in a technical solution, unless otherwise specified, and there are no contradictions or mutual constraints, then each "optional" option is independent.

[0044] In this invention, "room temperature" generally refers to 4℃~35℃, and can refer to 20℃±5℃. In some embodiments of this invention, room temperature refers to 20℃~30℃.

[0045] In one embodiment, the present invention provides a method for NO x A manganese-based catalyst for the synergistic removal of CO, wherein the manganese-based catalyst comprises manganese dioxide of naphthoic mineral type and alkaline earth metal elements and copper elements doped in the naphthoic mineral type manganese dioxide.

[0046] It is difficult to achieve NO at low temperatures using single Mn-based oxides. x To address the issue of synergistic removal of NOx and CO, this invention provides a manganese-based catalyst. This catalyst is co-doped with alkaline earth metals and copper in manganese dioxide of the sodium manganese hydrate type. On the one hand, alkaline earth metals can enter tunnels and be captured by "alkali-active" sites, protecting the catalytic active sites from alkali poisoning. On the other hand, the synergistic effect between copper and manganese species enhances the catalyst's low-temperature redox capability and surface reactive oxygen migration ability. The catalyst prepared by co-doping with alkaline earth metals and copper can leverage the synergistic effect of the two dopant elements, significantly improving its resistance to alkali metal and / or alkaline earth metal poisoning. It can achieve high NOx and CO removal rates under mild conditions, especially under NH3-SCR synergistic CO oxidation conditions, exhibiting good catalytic performance and long-term stability. It is suitable for industrial flue gas treatment systems and has significant theoretical and practical value.

[0047] In some embodiments, the alkaline earth metal element includes calcium and / or magnesium, preferably calcium.

[0048] In some embodiments, the alkaline earth metal element is doped into the interlayer of manganese dioxide in the form of intercalation ions.

[0049] In some embodiments, the copper element is doped into naphthoic manganese dioxide in a lattice-doped manner.

[0050] In the manganese-based catalyst provided by this invention, alkaline earth metals are doped into the interlayer of manganese dioxide of the sodium manganese dioxide type by forming intercalation ions. The intercalation effect of different alkaline earth metals varies. Calcium ions are preferred as intercalation ions, and the synergistic catalytic effect is better.

[0051] In the manganese-based catalyst provided by this invention, alkaline earth metals and copper are doped into naphthoic manganese dioxide using different doping methods, which can better exert the catalytic activity of the catalyst in the low-temperature NH3-SCR synergistic CO oxidation system. Specifically, the alkaline earth metals mainly stabilize the layered structure of naphthoic manganese dioxide through interlayer intercalation, reducing the Na+ content in the naphthoic manganese dioxide. + Species further increase Brønsted acid sites and surface adsorbed oxygen content, thereby promoting NO x The adsorption and activation of NH3 enhances the performance of low-temperature SCR; copper mainly regulates the redox properties of manganese dioxide of the sodium manganese oxide type through lattice doping, forming catalytic active sites that are conducive to CO adsorption and activation, and promoting the generation, migration and recycling of surface active oxygen species.

[0052] In one embodiment, the present invention provides a method for NO as described in the above embodiments. xA method for preparing a manganese-based catalyst for the synergistic removal of CO, the method comprising the following steps:

[0053] A precipitation reaction is carried out using a mixture of manganese source, alkaline earth metal source, copper source, oxidant, precipitant and solvent to obtain a precursor;

[0054] The precursor is calcined to obtain the product used for NO. x Manganese-based catalysts for the synergistic removal of CO.

[0055] The preparation method provided by this invention is mild, yields high results, and requires no complicated processing. A manganese-based catalyst with excellent catalytic performance and resistance to toxicity can be obtained through a simple precipitation and calcination process.

[0056] In some embodiments, the present invention does not limit the mixing method of raw materials during the preparation process. Any method that can achieve the reaction without affecting the doping effect without violating the overall technical concept of the present invention is applicable.

[0057] Example, but not limitation, of the present invention provides a hybrid method:

[0058] A manganese source, an alkaline earth metal source, a copper source, and a solvent are mixed to obtain a metal source solution; an oxidant, a precipitant, and a solvent are mixed to obtain a precipitated oxidation solution.

[0059] The metal source solution is added dropwise to the precipitate oxidation solution to carry out the precipitation reaction.

[0060] Optionally, the precipitation reaction includes a stirring reaction.

[0061] Optionally, the precipitation reaction is carried out at room temperature.

[0062] In some embodiments, the manganese source includes any one or a combination of at least two of manganese sulfate, manganese nitrate, or manganese acetate, preferably manganese acetate.

[0063] The manganese source provided by this invention is not unique, and all of them can be used to prepare layered sodium manganese dioxide. In particular, manganese acetate is selected as the manganese source, resulting in a catalyst material with a more stable structure and better synergistic effect with alkaline earth metals and copper.

[0064] In some embodiments, the copper source includes copper nitrate and / or copper sulfate, preferably copper nitrate.

[0065] In the preparation process of this invention, the type of copper source has a significant impact on the formation of the catalyst structure and its catalytic performance. Different copper sources, due to differences in anion types and coordination environments, affect the introduction mode, dispersion state, and interaction between Cu species and Mn species, thereby regulating the crystal phase structure, surface oxygen species, Mn valence state distribution, and acidity characteristics of the catalyst. In comparison, the preferred use of copper nitrate as the copper source in this invention is generally more conducive to obtaining uniformly dispersed Cu species, resulting in superior catalytic performance and anti-toxicity effects.

[0066] In some embodiments, the alkaline earth metal source is selected from the nitrate system.

[0067] In some embodiments, the oxidant includes potassium permanganate and / or hydrogen peroxide.

[0068] In some embodiments, during the preparation process, the molar ratio of the total molar amount of manganese, the molar amount of alkaline earth metals, and the molar amount of copper is 1:(0.125~0.5):(0.05~0.5), for example 1:0.125:0.05, 1:0.125:0.1, 1:0.125:0.15, 1:0.125:0.2, 1:0.125:0.25, 1:0.125:0.3, 1:0.125:0.35, 1:0.125:0.4, 1:0.125:0.45, 1:0.125:0.5, 1:0.3:0.05, 1:0.3:0.1, 1:0.3:0.15, 1:0.3:0.2, 1:0.3:0.25, 1:0.3:0. 3, 1:0.3:0.35, 1:0.3:0.4, 1:0.3:0.45, 1:0.3:0.5, 1:0.4:0.05, 1:0.4:0.1, 1:0.4:0.15, 1:0.4:0.20, 1:0.4:0.25, 1:0.4:0.3, 1:0.4:0.35, 1:0.4:0.4 , 1:0.4:0.45, 1:0.4:0.5, 1:0.5:0.05, 1:0.5:0.1, 1:0.5:0.15, 1:0.5:0.2, 1:0.5:0.25, 1:0.5:0.3, 1:0.5:0.35, 1:0.5:0.4, 1:0.5:0.45 or 1:0.5:0.5, etc.

[0069] Furthermore, in the preparation process, the molar ratio of the total molar amount of manganese, the molar amount of alkaline earth metals, and the molar amount of copper is preferably 1:0.5:(0.05~0.5), for example 1:0.5:0.05, 1:0.5:0.1, 1:0.5:0.15, 1:0.5:0.2, 1:0.5:0.25, 1:0.5:0.3, 1:0.5:0.35, 1:0.5:0.4, 1:0.5:0.45, or 1:0.5:0.5, etc.

[0070] It is understood that the total molar amount of manganese in this invention is determined based on the specific raw material selection; for example, when potassium permanganate is used as the oxidant, the total molar amount of manganese is the sum of the molar amounts of manganese in the manganese source and potassium permanganate; when a non-manganese substance, such as hydrogen peroxide, is used as the oxidant, the total molar amount of manganese is the molar amount of manganese in the manganese source.

[0071] Correspondingly, the molar amount of alkaline earth metal is the same as the molar amount of alkaline earth metal in the alkaline earth metal source; the molar amount of copper is the same as the molar amount of copper in the copper source.

[0072] In the preparation process of this invention, by controlling the molar ratio of total manganese, alkaline earth metals, and copper to 1:(0.125~0.5):(0.05~0.5), the synergistic regulatory effect between alkaline earth metal intercalation doping and copper lattice doping is further enhanced. More preferably, the molar ratio of total manganese, alkaline earth metals, and copper to 1:0.5 (0.05~0.5) is more favorable for the reaction of NH3 and NO. x Adsorption activation resulted in superior NH3-SCR reactivity. Further adjusting the copper doping amount to 0.05–0.5% enhanced the catalyst's redox performance and CO adsorption activation capacity, leading to a better match between NH3-SCR and CO oxidation activities. This improved the catalyst's NO oxidation performance in low-temperature NH3-SCR synergistic CO oxidation systems. x It exhibits synergistic CO removal performance, resistance to poisoning, and long-term operational stability.

[0073] In some embodiments, the precipitant includes an alkali.

[0074] Optionally, the alkali includes sodium hydroxide and / or potassium hydroxide.

[0075] In some embodiments, the pH value of the precipitation reaction is 11 to 13, such as 11, 11.3, 11.5, 11.8, 12, 12.3, 12.5, 12.8 or 13.

[0076] It is understood that the present invention does not limit the specific amount of precipitant used, as long as the precipitation reaction is carried out in an environment with a pH value of 11-13.

[0077] In some embodiments, the precipitation reaction time is 0.5h to 3h, for example 0.5h, 1h, 1.5h, 2, 2.5h or 3h.

[0078] In some embodiments, after the precipitation reaction, the sample is washed with water and dried to obtain the precursor.

[0079] The present invention washes the product after precipitation reaction with water to remove residual alkali and other impurities on its surface, thereby improving the purity of the material. After drying, the precursor is obtained.

[0080] In some embodiments, the heating rate of the calcination treatment is 1℃ / min to 3℃ / min, for example, 1℃ / min, 2℃ / min or 3℃ / min.

[0081] In some embodiments, the roasting temperature of the roasting treatment is 400℃~600℃, such as 400℃, 425℃, 450℃, 475℃, 500℃, 525℃, 550℃, 575℃ or 600℃.

[0082] In some embodiments, the roasting time of the roasting treatment is 2h to 5h, for example 2h, 3h, 4h or 5h.

[0083] In the preparation process of this invention, the calcination conditions have a significant impact on the physicochemical properties of the catalyst. Selecting a suitable calcination temperature, especially 400℃~600℃, helps to fully decompose the precursor and form the active phase, resulting in a catalyst material with uniform doping and a complete crystalline structure. This avoids grain growth and a decrease in specific surface area caused by improper calcination temperature.

[0084] In addition, an appropriate heating rate can promote the dispersion of active components and avoid particle agglomeration; it can also prevent excessively rapid heating rates from causing local sintering and structural collapse, which would affect catalyst performance.

[0085] In one embodiment, the present invention also provides an application of a manganese-based catalyst, the application comprising using the manganese-based catalyst as described in the above embodiments or the manganese-based catalyst as described in the above embodiments for NO. x Synergistic removal with CO.

[0086] In some implementations, the NO x Co-removal methods with CO include:

[0087] Under the catalytic action of manganese-based catalysts, NH3-SCR and CO oxidation are synergistically catalyzed to produce NO. x And CO.

[0088] In some embodiments, the catalytic reaction temperature is 30°C to 275°C, for example, 30°C, 50°C, 75°C, 100°C, 125°C, 150°C, 175°C, 200°C, 225°C, 250°C, or 275°C.

[0089] The manganese-based catalyst provided by this invention can synergistically catalyze NO oxidation in NH3-SCR and CO oxidation. x In the CO reaction process, the reaction temperature is lowered, allowing the purification process to be carried out at a lower temperature. The catalytic conditions are relatively mild, and the catalytic performance is excellent, with a removal rate of over 90%.

[0090] Furthermore, this invention does not apply to NO. x Other catalytic conditions in the synergistic removal of CO are limited, and those skilled in the art can make adaptive selections and adjustments based on the actual content in the industrial flue gas.

[0091] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0092] Example 1

[0093] This embodiment provides a method for NO x A manganese-based catalyst for the synergistic removal of CO, the manganese-based catalyst comprising naphthoic manganese dioxide and alkaline earth metal elements calcium and copper doped in the naphthoic manganese dioxide; wherein, calcium is doped in the interlayer of the naphthoic manganese dioxide in the form of intercalation ions, while copper is doped in the naphthoic manganese dioxide in the form of lattice doping.

[0094] The preparation method of the manganese-based catalyst is as follows:

[0095] 2.05 g of manganese acetate tetrahydrate, 1.41 g of calcium acetate tetrahydrate, and 0.15 g of copper nitrate trihydrate were weighed and dissolved in 15 mL of water to obtain a metal ion precursor solution. 7.50 g of sodium hydroxide and 0.55 g of potassium permanganate were weighed and dissolved in 90 mL of water to obtain a precipitation oxidation solution. The molar ratio of Mn(manganese acetate tetrahydrate + potassium permanganate), Ca, and Cu in the entire preparation system was 1:0.5:0.05. The two solutions were then mixed and the precipitation reaction was carried out under continuous stirring for 2 h. After the precipitation reaction, the resulting solid was filtered, washed with water and ethanol, and dried in a 100 °C oven to obtain the precursor. Finally, the precursor was calcined in air at a heating rate of 2 °C / min to 400 °C for 5 h to obtain the manganese-based catalyst (MnCa). 0.5 Cu 0.05 express).

[0096] Example 2

[0097] The difference between this embodiment and Example 1 is that, in the preparation process of this embodiment, the corresponding molar ratio of Mn, Ca, and Cu in the entire preparation system is 1:0.5:0.125, and the mass of copper nitrate trihydrate is adaptively adjusted to 0.36g (based on MnCa). 0.5 Cu 0.125 express).

[0098] All other conditions remain the same as in Example 1.

[0099] Example 3

[0100] The difference between this embodiment and Example 1 is that, in the preparation process of this embodiment, the corresponding molar ratio of Mn, Ca, and Cu in the entire preparation system is 1:0.5:0.25, and the mass of copper nitrate trihydrate is adaptively adjusted to 0.75g (based on MnCa). 0.5 Cu 0.25 express).

[0101] All other conditions remain the same as in Example 1.

[0102] Example 4

[0103] The difference between this embodiment and Example 1 is that, in the preparation process of this embodiment, the corresponding molar ratio of Mn, Ca, and Cu in the entire preparation system is 1:0.5:0.5, and the mass of copper nitrate trihydrate is adaptively adjusted to 1.45g (based on MnCa). 0.5 Cu 0.5 express).

[0104] All other conditions remain the same as in Example 1.

[0105] Example 5

[0106] The difference between this embodiment and Embodiment 2 is that, in the preparation process of this embodiment, the corresponding molar ratio of Mn, Ca and Cu in the entire preparation system is 1:0.5:0.01, and the mass of copper nitrate trihydrate is adjusted to 0.03g.

[0107] All other conditions remain the same as in Example 2.

[0108] Example 6

[0109] The difference between this embodiment and Embodiment 2 is that, in the preparation process of this embodiment, the corresponding molar ratio of Mn, Ca and Cu in the entire preparation system is 1:0.5:0.55, and the mass of copper nitrate trihydrate is adjusted to 1.57g.

[0110] All other conditions remain the same as in Example 2.

[0111] Example 7

[0112] The difference between this embodiment and Example 2 is that in this embodiment, the molar ratio of Mn, Ca and Cu in the entire preparation system is 1:0.25:0.125, and the mass of calcium acetate tetrahydrate is adjusted to 0.68g.

[0113] All other conditions remain the same as in Example 2.

[0114] Example 8

[0115] The difference between this embodiment and Example 2 is that in this embodiment, the molar ratio of Mn, Ca and Cu in the entire preparation system is 1:0.125:0.125, and the mass of calcium acetate tetrahydrate is adjusted to 0.34g.

[0116] All other conditions remain the same as in Example 2.

[0117] Example 9

[0118] The difference between this embodiment and Example 2 is that in this embodiment, the molar ratio of Mn, Ca and Cu in the entire preparation system is 1:0.1:0.125, and the mass of calcium acetate tetrahydrate is adjusted to 0.27g.

[0119] All other conditions remain the same as in Example 2.

[0120] Example 10

[0121] The difference between this embodiment and Example 2 is that in this embodiment, the molar ratio of Mn, Ca and Cu in the entire preparation system is 1:0.55:0.125, and the mass of calcium acetate tetrahydrate is adjusted to 1.5g.

[0122] All other conditions remain the same as in Example 2.

[0123] Example 11

[0124] The difference between this embodiment and Embodiment 2 is that the alkaline earth metal doping element in this embodiment is magnesium.

[0125] In the preparation method, calcium nitrate tetrahydrate is adapted to magnesium nitrate.

[0126] All other conditions remain the same as in Example 2.

[0127] Example 12

[0128] The difference between this embodiment and Embodiment 2 is that the calcination temperature in this embodiment is 600℃.

[0129] All other conditions remain the same as in Example 2.

[0130] Comparative Example 1

[0131] The difference between this comparative example and Example 2 is that the manganese-based catalyst in this comparative example does not undergo copper doping (using MnCa). 0.5 express).

[0132] In the corresponding preparation method, copper acetate trihydrate is not added.

[0133] All other conditions remain the same as in Example 2.

[0134] Figure 1 The XRD patterns of the manganese-based catalysts provided in Examples 1-4 and Comparative Example 1 of the present invention are shown.

[0135] Figure 2 TEM images of the manganese-based catalysts provided in Example 2 and Comparative Example 1 of the present invention are shown.

[0136] from Figure 1 It can be seen that after calcination at 400℃, the Ca-doped sample formed a calcium-stabilized Todorokite-type manganese oxide with a 3×3 tunnel structure, indicating that Ca... 2+ The introduction of Cu helps induce the transformation of sucralose into a large tunnel structure. Notably, Cu doping causes the diffraction peaks of sucralose to shift to lower angles, indicating an increase in interplanar spacing and some lattice distortion. Figure 2 It can be seen that the lattice spacing increases after Cu doping, indicating that Cu... 2+ (73pm) replaces Mn 4+ (53pm) further confirmed Figure 1 The result.

[0137] Comparative Example 2

[0138] The difference between this comparative example and Example 2 is that the manganese-based catalyst in this comparative example does not undergo calcium doping, that is, only copper doping is performed in the manganese-based catalyst.

[0139] In the corresponding preparation method, calcium acetate tetrahydrate is not added.

[0140] All other conditions remain the same as in Example 2.

[0141] Comparative Example 3

[0142] The difference between this comparative example and Example 2 is that the manganese-based catalyst in this comparative example is neither copper-doped nor calcium-doped.

[0143] In the corresponding preparation method, calcium acetate tetrahydrate and copper nitrate trihydrate (represented as NaMn) are not added.

[0144] All other conditions remain the same as in Example 2.

[0145] NO x Co-removal with CO

[0146] The manganese-based catalysts provided in the examples and comparative examples were subjected to NO treatment. x For synergistic removal of CO, the catalyst powders provided in the examples and comparative examples were tableted, ground, and sieved. Samples of 40-60 mesh particles were placed in a quartz tube and tested in a fixed-bed reactor. Specific testing methods included: using the manganese-based catalysts provided in the examples and comparative examples as the reaction catalyst; [NO] = [NH3] = 500 ppm, CO = 5000 ppm, [O2] = 10 vol.%, N2 as the equilibrium gas; a total reaction gas flow rate of 500 mL / min; a reaction temperature range of 30℃-275℃; and holding the reaction at each temperature for 30 min until equilibrium was reached. The concentrations of reactants NH3 and NO, and reaction byproducts NO2 and N2O were measured using a Thermo IS50 infrared spectroscopy device. The catalyst dosage corresponded to a space velocity of 50,000 h⁻¹. -1 .

[0147] Figure 3 The performance test graphs of the manganese-based catalysts provided in Examples 1-4 and Comparative Example 1 for CO catalytic oxidation in NH3-SCR synergistic CO oxidation are shown.

[0148] Figure 4 Examples 1-4 and Comparative Example 1 illustrate the use of manganese-based catalysts for NO oxidation in NH3-SCR-co-CO oxidation. x Performance test chart for catalysis.

[0149] Using the above test removal method, NO was found to be... x The temperature range where both CO conversion rate and CO conversion rate are ≥90% (T) 90 Temperature window), the results are shown in Table 1.

[0150] Table 1

[0151]

[0152] From Table 1 and Figures 1 to 4 We can conclude that:

[0153] The manganese-based catalyst provided by this invention, through co-doping of alkaline earth metals and copper in naphthoic manganese dioxide, exhibits resistance to alkali metal / alkaline earth metal (alkali metal and / or alkaline earth metal) poisoning and can maintain high NO content under mild conditions. x It exhibits good catalytic performance and long-term stability, especially under the synergistic CO oxidation conditions of NH3-SCR and CO removal rate.

[0154] Data analysis of Examples 1 and 2-10 shows that, during the preparation process, by controlling the molar ratio of the total molar amount of manganese, the molar amount of alkaline earth metal, and the molar amount of copper to 1:(0.125~0.5):(0.05~0.5), this suitable molar ratio range helps to achieve synergistic regulation between the introduction of alkaline earth metal and copper doping, which is beneficial to improving the structural characteristics, surface acidity, and redox performance of the catalyst, thereby enhancing its catalytic performance in the low-temperature NH3-SCR synergistic CO oxidation system. Furthermore, when the preferred molar ratio of the total molar amount of manganese, the molar amount of alkaline earth metal, and the molar amount of copper is 1:0.5:(0.05~0.5), the introduction of alkaline earth metal is more conducive to promoting the reaction of NH3 and NO. x The adsorption and activation of CO by copper enhances the catalyst's NH3-SCR reactivity, resulting in superior activity. Furthermore, the introduction of an appropriate amount of copper further strengthens the catalyst's redox performance and CO adsorption / activation capacity, leading to a better match between NH3-SCR and CO oxidation activities, thereby improving the catalyst's ability to react with NO. x It has synergistic removal performance with CO, and is beneficial to improving its resistance to poisoning and long-term operational stability.

[0155] Data analysis of Examples 2 and 11 shows that calcium is selected as the alkaline earth metal in the manganese-based catalyst of the present invention, which can improve the specific surface area and surface acidity of the catalyst, promote the adsorption and activation of NH3 and NOx, and thus improve the NH3-SCR reaction activity of the catalyst.

[0156] Analysis of the data from Examples 2 and Comparative Examples 1-3 shows that in the manganese-based catalyst of the present invention, the doping of alkaline earth metals and copper must work synergistically to enhance the NO oxidation performance of the catalyst in the low-temperature NH3-SCR synergistic CO oxidation system. x Synergistic removal performance with CO. Specifically, the introduction of alkaline earth metals is beneficial for regulating the structural characteristics and surface acidity of the catalyst, promoting the removal of NH3 and NO. x The adsorption and activation of CO are enhanced by copper; the introduction of copper further improves the redox performance and CO adsorption and activation capacity of the catalyst. The synergistic effect of these two elements allows for a better match between the NH3-SCR activity and the CO oxidation activity, thereby achieving NO… x Highly efficient synergistic removal with CO.

[0157] Catalyst resistance to alkali / alkaline earth metals testing

[0158] The catalyst provided in Example 2 was tested for resistance to alkali metals and alkaline earth metals, specifically in the following examples.

[0159] Example 2-1

[0160] This application example provides an alkali metal resistant catalyst, which is treated using the manganese-based catalyst provided in Example 2, as detailed below:

[0161] 1.5 g of the manganese-based catalyst provided in Example 2 was added to 60 mL of deionized water, along with a certain amount of potassium nitrate (added at a K2O mass fraction of 0.1% relative to the manganese-based catalyst in Example 2). The mixture was stirred at room temperature for 8 h, then rotary evaporated at 80 °C to obtain a black powder. This powder was then dried overnight at 100 °C. Finally, it was calcined at 400 °C for 5 h in air at a heating rate of 2 °C / min. The resulting catalyst was then calcined to obtain 0.1% K2O poi-MnCa. 0.5 Cu 0.125 catalyst.

[0162] Example 2-2

[0163] This application example provides an alkaline earth-resistant metal catalyst, which is treated with the manganese-based catalyst provided in Example 2, as detailed below:

[0164] 1.5 g of the manganese-based catalyst provided in Example 2 was added to 60 mL of deionized water, along with a certain amount of magnesium nitrate (added at a mass fraction of 1% for MgO relative to the manganese-based catalyst in Example 2). The mixture was stirred at room temperature for 8 h, then rotary evaporated at 80 °C to obtain a black powder. This powder was then dried overnight at 100 °C. Finally, it was calcined at 400 °C for 5 h in air at a heating rate of 2 °C / min. The resulting catalyst was then calcined to obtain 1% MgO poi-MnCa 0.5 Cu 0.125 catalyst.

[0165] Example 2-3

[0166] This application example provides an alkaline earth-resistant metal catalyst, which is treated with the manganese-based catalyst provided in Example 2, as detailed below:

[0167] 1.5 g of the manganese-based catalyst provided in Example 2 was added to 60 mL of deionized water, along with a certain amount of calcium nitrate (calculated as 1% CaO relative to the manganese-based catalyst in Example 2 by mass fraction). The mixture was stirred at room temperature for 8 h, then rotary evaporated at 80 °C to obtain a black powder. This powder was then dried at 100 °C overnight. Finally, it was calcined at 400 °C for 5 h in air at a heating rate of 2 °C / min. The resulting catalyst was then calcined to obtain 1% CaO poi-MnCa 0.5 Cu 0.125 catalyst.

[0168] The catalysts provided in Examples 2-1, 2-2, and 2-3 were subjected to NO testing using the exact same procedure as in Example 1.x Synergistic removal with CO, test results are as follows Figure 5 and Figure 6 As shown.

[0169] Figure 5 The performance test graphs of the manganese-based catalysts provided in Example 2 (fresh), Example 2-1, Example 2-2, and Example 2-3 for CO catalytic oxidation in NH3-SCR synergistic CO oxidation are shown.

[0170] Figure 6 The manganese-based catalysts provided in Example 2 (fresh), Example 2-1, Example 2-2, and Example 2-3 are shown for the co-oxidation of NO in NH3-SCR with CO. x Performance test chart for catalysis.

[0171] from Figure 5 and Figure 6 It can be seen that the manganese-based catalyst provided by the present invention maintains a relatively stable overall catalytic performance after being poisoned by a low content of alkali metal or alkaline earth metal, thus the catalyst can exhibit good resistance to alkali / alkaline earth metal poisoning.

[0172] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for NO x A manganese-based catalyst for the synergistic removal of CO, characterized in that, The manganese-based catalyst comprises manganese dioxide of the sodium manganese oxide type and alkaline earth metal elements and copper elements doped into the sodium manganese oxide type manganese dioxide.

2. The manganese-based catalyst according to claim 1, characterized in that, The alkaline earth metal elements include calcium and / or magnesium; And / or, the alkaline earth metal element is doped into the interlayer of manganese dioxide in the form of intercalation ions; And / or, the copper element is doped into manganese dioxide of the naphthoic type by means of lattice doping.

3. The manganese-based catalyst according to claim 1, characterized in that, The alkaline earth metal element includes calcium.

4. A method for NO as described in any one of claims 1-3 x A method for preparing a manganese-based catalyst for the synergistic removal of CO, characterized in that, The preparation method includes the following steps: A precipitation reaction is carried out using a mixture of manganese source, alkaline earth metal source, copper source, oxidant, precipitant and solvent to obtain a precursor; The precursor is calcined to obtain the product used for NO. x Manganese-based catalysts for the synergistic removal of CO.

5. The preparation method according to claim 4, characterized in that, The manganese source includes any one or a combination of at least two of manganese sulfate, manganese nitrate, or manganese acetate. And / or, the copper source includes copper nitrate and / or copper sulfate; And / or, the oxidant includes potassium permanganate and / or hydrogen peroxide; And / or, in the preparation process, the molar ratio of the total molar amount of manganese, the molar amount of alkaline earth metals, and the molar amount of copper is 1:(0.125~0.5):(0.05~0.5). And / or, the precipitant includes a base.

6. The preparation method according to claim 5, characterized in that, The manganese source includes manganese acetate; And / or, the copper source includes copper nitrate; And / or, the molar ratio of manganese in the manganese source, alkaline earth metal in the alkaline earth metal source, and copper in the copper source is 1:0.5 (0.05~0.5).

7. The preparation method according to claim 4 or 5, characterized in that, The pH value of the precipitation reaction is 11-13; And / or, the precipitation reaction takes 0.5 h to 3 h; And / or, after the precipitation reaction, the sample is washed with water and dried to obtain the precursor; And / or, the heating rate of the calcination treatment is 1℃ / min to 3℃ / min, the calcination temperature of the calcination treatment is 400℃ to 600℃, and the calcination time of the calcination treatment is 2h to 5h.

8. The application of a manganese-based catalyst, characterized in that, The application includes using the manganese-based catalyst as described in any one of claims 1-3 or the manganese-based catalyst as described in any one of claims 4-7 for NO. x Synergistic removal with CO.

9. The application according to claim 8, characterized in that, The NO x Co-removal methods with CO include: Under the catalytic action of manganese-based catalysts, NH3-SCR and CO oxidation are synergistically catalyzed to produce NO. x and CO.

10. The application according to claim 9, characterized in that, The catalytic reaction temperature is 30℃~275℃.

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