Preparation of manganese oxide molecular sieve catalyst and application of manganese oxide molecular sieve catalyst in cooperation with NO and CO removal

Abstract

The invention discloses preparation of a manganese oxide molecular sieve catalyst and application of the manganese oxide molecular sieve catalyst in synergism of NO and CO removal. The catalyst is composed of a molecular sieve and manganese oxide, and the mass ratio of the manganese oxide to the molecular sieve is 1: 3-1: 9. The preparation method comprises the following steps: (1) preparing manganese oxides with different valence states and morphologies through a hydrothermal method for later use; and (2) mixing and stirring the manganese oxide and the molecular sieve in proportion by adopting a solid-phase diffusion method, and then roasting to obtain the manganese oxide molecular sieve catalyst. The manganese oxide molecular sieve catalyst disclosed by the invention is simple in preparation method, low in cost and high in reaction activity, can realize synergistic removal of NO and CO, and has a good industrial application prospect.

Description

Technical Field

[0001] The invention relates to a denitration catalyst and its preparation and application, in particular to a manganese oxide molecular sieve catalyst and its application in synergistic removal of NO and CO. Background Art

[0002] Carbon monoxide (CO) is a well-known air pollutant that is widely present in industrial furnaces, metallurgical industry fumes and motor vehicle exhaust. It is known as the "silent killer". CO poses a serious threat to human health. It combines with hemoglobin to weaken the oxygen delivery capacity and damage the central nervous system. When the CO concentration in the air exceeds 30mg / m 3 It is toxic to the human body.

[0003] Nitrogen oxides (NO x ) is one of the important causes of environmental problems such as acid rain, ozone layer depletion, haze and global warming. The steel and nonferrous metallurgical industries consume a large amount of fossil fuels and mineral resources, emit a large amount of air pollutants, and bring great pressure to the environment.

[0004] At present, flue gas dust removal and desulfurization technologies are relatively mature, but the removal technology of NO and CO, which are the main pollutants, is still under development and improvement. CO selective catalytic reduction (CO-SCR) technology is widely regarded as an effective method for removing NO and CO. However, under oxygen-rich conditions, CO tends to be oxidized to CO 2 , but not NO. 3 -SCR) technology is widely used because of its excellent performance in efficiently removing NO from sintering flue gas. In addition, the large amount of heat energy released during the catalytic oxidation of CO has the potential to be used to reduce NH 3 -SCR denitrification system energy consumption and operating costs. 3 -SCR and CO oxidation reaction to simultaneously remove NO and CO from flue gas is a very promising direction, but the key to NO and CO removal technology lies in the research of suitable catalysts.

[0005] Manganese oxide catalysts have a high efficiency in low-temperature denitrification due to their variable valence states, unique crystal structure, and strong oxygen transfer capacity. 3 -SCR catalytic reaction has been widely studied. However, manganese oxide catalysts produce by-products such as N 2 O and N 2 The problem of low selectivity. In addition, the catalytic activity of a single manganese oxide catalyst in removing CO at lower temperatures is limited, making it difficult to simultaneously and efficiently eliminate NO and CO in low-temperature flue gas.

[0006] The molecular sieve carrier has a rich pore structure and a large specific surface area, which provide adsorption sites for catalytic reactions. It has an adjustable silicon-aluminum ratio, which provides abundant acid sites for catalytic reactions. Its easily modifiable topological structure promotes the modification of the molecular sieve matrix by active components. Catalysts with ZSM-5, SSZ-13 and Beta molecular sieves as carriers and loaded with transition metal oxides have been successfully used in NH 3 -SCR field has received extensive attention. For example, CN 116689023A discloses a preparation method and denitration application of a composite manganese oxide catalyst, wherein a manganese-cerium catalyst is combined with a CHA type microporous molecular sieve to obtain a composite catalyst.

[0007] However, in order to avoid the generation of byproduct N during denitrification 2 O and overcome N 2 The problem of low selectivity is that the content of manganese oxide in the current manganese oxide molecular sieve catalyst is generally not higher than 10%, and the catalyst at this concentration has a low removal rate for CO, which cannot achieve the effect of synergistic removal. In addition, the current manganese oxide molecular sieve catalyst is usually prepared by hydrothermal method or ion exchange method, which causes a large amount of manganese oxide to enter the framework and gaps of the molecular sieve, resulting in a high conversion rate for NO, while the conversion rate for CO is low, which also cannot achieve a good synergistic removal effect. Therefore, it is urgent to develop a molecular sieve catalytic material that can efficiently and synergistically remove NO and CO. Summary of the invention

[0008] In order to solve the above technical problems, the present invention provides a manganese oxide molecular sieve catalyst and its application in the synergistic removal of NO and CO. The manganese oxide molecular sieve catalyst of the present invention has a simple preparation method, low cost, high reaction activity, can achieve synergistic removal of NO and CO, and has good industrial application prospects.

[0009] One of the technical solutions of the present invention:

[0010] Provided is a manganese oxide molecular sieve catalyst, which consists of a molecular sieve and manganese oxide, wherein the mass ratio of the manganese oxide to the molecular sieve is 1:3-1:9.

[0011] Preferably, the manganese oxide molecular sieve catalyst is α-MnO 2 ,β-MnO 2 ,γ-MnO 2 ,δ-MnO 2 , Mn 2 O 3 or Mn 3 O 4 One of them.

[0012] Preferably, the aforementioned manganese oxide molecular sieve catalyst is a ZSM-5 molecular sieve.

[0013] Preferably, in the aforementioned manganese oxide molecular sieve catalyst, the mass ratio of manganese oxide to molecular sieve is 1:5.

[0014] Preferably, the manganese oxide molecular sieve catalyst has a pore size of 1.7-3 nm and a specific surface area of ​​300-500 m 2 / g.

[0015] The manganese oxide content in the manganese oxide molecular sieve catalyst of this scheme is 10%-25%, which is higher than the manganese oxide content in the conventional manganese oxide molecular sieve catalyst. While ensuring a good NO removal rate, the CO removal rate is also improved, achieving the synergistic removal of NO and CO.

[0016] The second technical solution of the present invention:

[0017] Provided is a method for preparing a manganese oxide molecular sieve catalyst, comprising the following steps:

[0018] (1) preparing manganese oxide by a hydrothermal method and setting aside;

[0019] (2) The manganese oxide and the molecular sieve are mixed and stirred in proportion by a solid phase diffusion method, and then calcined to obtain a manganese oxide molecular sieve catalyst.

[0020] Preferably, in the aforementioned method for preparing the manganese oxide molecular sieve catalyst, the solvent used in the solid phase diffusion method is ethanol.

[0021] Preferably, in the aforementioned method for preparing the manganese oxide molecular sieve catalyst, in the solid phase diffusion method, the solid-liquid ratio of the solid to the solvent is 1:3-1:5; the stirring temperature is 35-50° C., and the stirring time is 0.5-1.5 h.

[0022] Preferably, in the aforementioned method for preparing the manganese oxide molecular sieve catalyst, the calcination temperature is 300-450° C., and the calcination time is 3-6 hours.

[0023] This scheme defines the preparation of manganese oxide molecular sieve catalysts, combines manganese oxide with molecular sieves by solid phase diffusion method, has good dispersion of active components, high catalytic activity, and large adsorption capacity of molecular sieve carriers, has good conversion effects on both NO and CO, and can achieve synergistic removal of NO and CO. In addition, the preparation process of this scheme is simple, low-cost, and suitable for industrial promotion.

[0024] The third technical solution of the present invention:

[0025] Provided is an application of a manganese oxide molecular sieve catalyst in the coordinated removal of NO and CO.

[0026] Beneficial effects of the present invention:

[0027] The manganese oxide content in the manganese oxide molecular sieve catalyst of the present invention is 10%-25%, which is higher than the manganese oxide content in the conventional manganese oxide molecular sieve catalyst. Through the reasonable ratio of manganese oxide and the reasonable matching of molecular sieves, while ensuring a good NO removal rate, the CO removal rate is also improved, thereby achieving the synergistic removal of NO and CO.

[0028] The present invention limits the preparation of manganese oxide molecular sieve catalysts. Manganese oxide is combined with molecular sieves by a solid phase diffusion method. The active components have good dispersibility and high catalytic activity. The molecular sieve carrier has a large adsorption capacity and has good conversion effects on both NO and CO, thereby achieving synergistic removal of NO and CO.

[0029] The preparation process of the invention is simple, the cost is low and it is suitable for industrial promotion.

[0030] In summary, the manganese oxide molecular sieve catalyst of the present invention has the advantages of simple preparation method, low cost, high reaction activity, and the ability to achieve synergistic removal of NO and CO, and has good industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is the XRD diagram of the manganese oxide@molecular sieve catalyst in Example 1 of the present invention;

[0032] Figure 2 (a) SEM image and (b) TEM image of the manganese oxide@molecular sieve catalyst in Example 1 of the present invention;

[0033] Figure 3 is (a)NH of the manganese oxide@molecular sieve catalyst in Example 1 of the present invention 3 -TPD diagram and (b) CO-TPD diagram.

[0034] like Figure 1 As shown, in the XRD pattern of the manganese oxide @ molecular sieve catalyst, no diffraction peak related to manganese oxide is observed, indicating that the manganese oxide in the manganese oxide @ molecular sieve catalyst exists in the form of small crystallites and has good dispersion.

[0035] like Figure 2 As shown, combined with the SEM image and TEM image of the manganese oxide@molecular sieve catalyst, the manganese oxide is uniformly dispersed on the surface of the molecular sieve matrix.

[0036] like Figure 3 As shown, the NH 3-TPD chart shows that NH 3 The desorption peak temperature range is 100-200℃, 250-400℃, 400-600℃, MnO 2 @ZSM-5 molecular sieve catalyst has strong ammonia storage capacity; the CO-TPD diagram of manganese oxide @ molecular sieve catalyst shows that the desorption peak temperature range of CO is 60-100℃ and 200-350℃, and MnO 2 @ZSM-5 molecular sieve catalyst has good CO adsorption capacity. DETAILED DESCRIPTION

[0037] The present invention will be further described below in conjunction with the embodiments, but they are not intended to limit the present invention.

[0038] In the performance test of the catalyst in the embodiments of the present invention and the comparative examples, the amount of the catalyst was 0.1 g (about 0.1 mL), the catalyst was mixed with 0.1 g of cordierite (60-80 mesh), and the simulated reaction gas conditions were 1000 ppm NO, 1000 ppm NH 3 , 2000ppm CO, 5vol% O 2 , the balance gas is N 2 , total gas flow rate is 300mL / min, GHSV is 90,000h -1 The concentrations of NO and CO were detected by Fourier transform infrared spectrometer, and the conversion rates of NO and CO were calculated by referring to the following formula:

[0039]

[0040] The pore size of the catalysts prepared in the examples of the present invention and the comparative examples is 1.7-3 nm, and the specific surface area is 300-500 m 2 / g.

[0041] Embodiments of the present invention

[0042] Embodiment 1:

[0043] Preparation of MnO 2 Powder: Take 4.10g (NH 4 ) 2 S 2 O 8 and 3.04gMnSO 4 ·H 2 O was dissolved in 72 mL of deionized water; MnO 2The precursor solutions were magnetically stirred for 30 minutes, transferred to a 100 mL polytetrafluoroethylene-lined stainless steel autoclave, and subjected to a hydrothermal reaction at 90°C for 24 hours. The precipitate after the hydrothermal reaction was filtered and collected, washed with deionized water until neutral, and dried at 80°C for 24 hours. The precipitate was then calcined at 300°C in an air atmosphere for 4 hours to obtain MnO 2 powder;

[0044] MnO 2 @Molecular sieve catalyst preparation: Mixing MnO by solid phase diffusion method 2 powder, ZSM-5 molecular sieve and ethanol, the grinding temperature and time are 35℃ and 1h respectively, in which MnO 2 The mass ratio of the mixture to ZSM-5 molecular sieve is 1:5, and the liquid-to-solid ratio is 1:4; the mixture is then calcined at 300 °C for 3 h to obtain MnO 2 @Molecular sieve catalyst.

[0045] Embodiment 2:

[0046] Preparation of Mn 2 O 3 Powder: Take 0.79g KMnO 4 and 0.90 g glucose were dissolved in 50 mL of deionized water; Mn 2 O 3 The precursor solutions were magnetically stirred for 30 minutes, transferred to a 100 mL polytetrafluoroethylene-lined stainless steel autoclave, and subjected to a hydrothermal reaction at 150°C for 10 hours. The precipitate after the hydrothermal reaction was filtered and collected, washed with deionized water until neutral, and dried at 80°C for 24 hours. The precipitate was then calcined at 500°C in an air atmosphere for 4 hours to obtain Mn 2 O 3 powder;

[0047] Mn 2 O 3 @Molecular sieve catalyst preparation: Mn was mixed by solid phase diffusion method 2 O 3 powder, ZSM-5 molecular sieve and ethanol, the grinding temperature and time are 50℃ and 0.5h respectively, among which Mn 2 O 3 The mass ratio of the mixture to ZSM-5 molecular sieve is 1:5, and the liquid-to-solid ratio is 1:3; the mixture is then calcined at 400 °C for 6 h to obtain Mn 2 O 3 @Molecular sieve catalyst.

[0048] Embodiment 3:

[0049] Preparation of Mn 3 O4 Powder: Take 1.08gMnSO 4 ·H 2 O and 5 mL of ammonia water were dissolved in 60 mL of deionized water; Mn 3 O 4 The precursor solutions were magnetically stirred for 30 minutes, transferred to a 100 mL polytetrafluoroethylene-lined stainless steel autoclave, and subjected to a hydrothermal reaction at 180°C for 6 hours. The precipitate after the hydrothermal reaction was filtered and collected, washed with deionized water until neutral, and dried at 80°C for 24 hours. The precipitate was then calcined at 300°C in an air atmosphere for 4 hours to obtain Mn 3 O 4 powder;

[0050] Mn 3 O 4 @Molecular sieve catalyst preparation: Mn was mixed by solid phase diffusion method 3 O 4 powder, ZSM-5 molecular sieve and ethanol, the grinding temperature and time are 40℃ and 1.5h respectively, in which Mn 3 O 4 The mass ratio of the mixture to ZSM-5 molecular sieve is 1:5, and the liquid-solid ratio is 1:5; the mixture is then calcined at 500°C for 4h to obtain Mn 3 O 4 @Molecular sieve catalyst.

[0051] Embodiment 4:

[0052] Preparation of α-MnO 2 Powder: Take 1.13g KMnO 4 and 0.47 gMnSO 4 ·H 2 O was dissolved in 72 mL of deionized water; α-MnO 2 The precursor solutions were magnetically stirred for 30 minutes, transferred to a 100 mL polytetrafluoroethylene-lined stainless steel autoclave, and subjected to a hydrothermal reaction at 160°C for 12 hours. The precipitate after the hydrothermal reaction was filtered and collected, washed with deionized water until neutral, and dried at 80°C for 24 hours. The precipitate was then calcined at 300°C in an air atmosphere for 4 hours to obtain α-MnO 2 powder;

[0053] α-MnO 2 @Molecular sieve catalyst preparation: Mixing α-MnO by solid phase diffusion method 2 powder, ZSM-5 molecular sieve and ethanol, the grinding temperature and time are 35℃ and 1h respectively, in which α-MnO 2The mass ratio of the mixture to ZSM-5 molecular sieve is 1:5, and the liquid-solid ratio is 1:4. The mixture is then calcined at 300 °C for 3 h to obtain α-MnO 2 @Molecular sieve catalyst.

[0054] Embodiment 5:

[0055] Preparation of β-MnO 2 Powder: Take 1.52gMnSO 4 ·H 2 O and 2.05 g (NH 4 ) 2 S 2 O 8 Dissolve in 72 mL of deionized water; 2 The precursor solutions were magnetically stirred for 30 minutes, transferred to a 100 mL polytetrafluoroethylene-lined stainless steel autoclave, and subjected to a hydrothermal reaction at 160°C for 12 hours. The precipitate after the hydrothermal reaction was filtered and collected, washed with deionized water until neutral, and dried at 80°C for 24 hours. The precipitate was then calcined at 300°C in an air atmosphere for 4 hours to obtain β-MnO 2 powder;

[0056] β-MnO 2 @Molecular sieve catalyst preparation: Mixing β-MnO by solid phase diffusion method 2 powder, ZSM-5 molecular sieve and ethanol, the grinding temperature and time were 35℃ and 1h respectively, of which β-MnO 2 The mass ratio of the mixture to ZSM-5 molecular sieve is 1:5, and the liquid-to-solid ratio is 1:4. The mixture is then calcined at 300 °C for 3 h to obtain β-MnO 2 @Molecular sieve catalyst.

[0057] Embodiment 6:

[0058] Preparation of γ-MnO 2 Powder: Take 3.04gMnSO 4 ·H 2 O and 4.10 g (NH 4 ) 2 S 2 O 8 Dissolve in 72 mL of deionized water; 2 The precursor solutions were magnetically stirred for 30 minutes, transferred to a 100 mL polytetrafluoroethylene-lined stainless steel autoclave, and hydrothermally reacted at 90°C for 24 hours; the precipitate after the hydrothermal reaction was filtered and collected, washed with deionized water until neutral, and dried at 80°C for 24 hours. Then, it was calcined at 300°C in air atmosphere for 4 hours to obtain γ-MnO 2 powder;

[0059] γ-MnO 2 @Molecular sieve catalyst preparation: Mixing γ-MnO by solid phase diffusion method 2 powder, ZSM-5 molecular sieve and ethanol, the grinding temperature and time are 35℃ and 1h respectively, in which γ-MnO 2 The mass ratio of the mixture to ZSM-5 molecular sieve is 1:5, and the liquid-solid ratio is 1:4. The mixture is then calcined at 300 °C for 3 h to obtain γ-MnO 2 @Molecular sieve catalyst.

[0060] Embodiment 7:

[0061] Preparation of δ-MnO 2 Powder: Take 0.25gMnSO 4 ·H 2 O and 1.35 g KMnO 4 Dissolve in 72 mL of deionized water; 2 The precursor solutions were magnetically stirred for 30 minutes, transferred to a 100 mL polytetrafluoroethylene-lined stainless steel autoclave, and subjected to a hydrothermal reaction at 180°C for 24 hours. The precipitate after the hydrothermal reaction was filtered and collected, washed with deionized water until neutral, and dried at 80°C for 24 hours. The precipitate was then calcined at 300°C in an air atmosphere for 4 hours to obtain δ-MnO 2 powder;

[0062] δ-MnO 2 @Molecular sieve catalyst preparation: Mixing δ-MnO by solid phase diffusion method 2 powder, ZSM-5 molecular sieve and ethanol, the grinding temperature and time are 35℃ and 1h respectively, among which δ-MnO 2 The mass ratio of the mixture to ZSM-5 molecular sieve is 1:5, and the liquid-solid ratio is 1:4. The mixture is then calcined at 300 °C for 3 h to obtain δ-MnO 2 @Molecular sieve catalyst.

[0063] Comparative Example 1:

[0064] This embodiment provides a MnO 2 @Molecular sieve catalyst, the difference from Example 1 is that the molecular sieve ZSM-5 is replaced by Beta molecular sieve of equal mass.

[0065] Comparative Example 2:

[0066] This embodiment provides a MnO 2 @Molecular sieve catalyst, the difference from Example 1 is that the molecular sieve ZSM-5 is replaced by an equal mass of SSZ-13 molecular sieve.

[0067] Comparative Example 3:

[0068] This comparative example provides a MnO 2 @Molecular sieve catalyst, the difference from Example 1 is that the molecular sieve ZSM-5 is replaced by an equal mass of carbon molecular sieve.

[0069] Embodiment 8:

[0070] This embodiment provides a MnO 2 @Molecular sieve catalyst, the difference from Example 1 is that MnO 2 The mass ratio to ZSM-5 molecular sieve is 1:3.

[0071] Embodiment 9:

[0072] This embodiment provides a MnO 2 @Molecular sieve catalyst, the difference from Example 1 is that MnO 2 The mass ratio to ZSM-5 molecular sieve is 1:7.

[0073] Embodiment 10:

[0074] This embodiment provides a MnO 2 @Molecular sieve catalyst, the difference from Example 1 is that MnO 2 The mass ratio to ZSM-5 molecular sieve is 1:9.

[0075] Comparative Example 4:

[0076] This comparative example provides a MnO 2 @Molecular sieve catalyst, the difference from Example 1 is that MnO 2 The mass ratio to ZSM-5 molecular sieve is 1:10.

[0077] Comparative Example 5:

[0078] This comparative example provides a MnO 2 @Molecular sieve catalyst, the difference from Example 1 is that MnO 2 The mass ratio to ZSM-5 molecular sieve is 1:15.

[0079] Comparative Example 6:

[0080] This comparative example provides a MnO 2 @Molecular sieve catalyst, the difference from Example 1 is that MnO 2 The mass ratio with ZSM-5 molecular sieve is 1:1.

[0081] Comparative Example 7:

[0082] This comparative example provides a MnO 2@Molecular sieve catalyst, the difference from Example 1 is that this comparative example adopts a hydrothermal method to combine manganese oxide and molecular sieve; the specific method is: disperse manganese oxide and molecular sieve in water, react at 70°C for 15h, then filter and dry, and calcine at 300°C for 3h.

[0083] The experimental results are summarized in the following table.

[0084] Table 1

[0085]

[0086] It can be seen from Table 1: It can be seen from Examples 1-7 that the NO and CO conversion rates of the manganese oxide @ ZSM-5 molecular sieve catalyst gradually increase with the increase of temperature, and at 300°C, the NO and CO conversion rates are both greater than 90%.

[0087] From the comparison of Examples 1, 2, and 3, it can be seen that MnO 2 The NO and CO conversion rates of @ZSM-5 molecular sieve catalyst are better than those of Mn 2 O 3 @ZSM-5 and Mn 3 O 4 @ZSM-5 catalyst, at 300℃, its NO and CO conversion rate is about 100%. This shows that manganese oxides of different valence states as active components will affect the NO and CO removal performance of the catalyst, among which MnO 2 MnO as active component 2 @ZSM-5 molecular sieve catalyst has the best catalytic performance.

[0088] From the comparison of Examples 4, 5, 6, and 7, it can be seen that α-MnO 2 The NO and CO conversion rates of @ZSM-5 molecular sieve catalyst are better than those of β-MnO 2 @ZSM-5,γ-MnO 2 @ZSM-5 and σ-MnO 2 @ZSM-5, at 300℃, the NO and CO conversion rates are about 100%. 2 The active components will affect the NO and CO removal performance of the catalyst, among which α-MnO 2 α-MnO as active component 2 @ZSM-5 molecular sieve catalyst has the best catalytic performance.

[0089] From the comparison between Example 1 and Comparative Example 1 and Comparative Example 2, it can be seen that MnO 2 @SSZ-13 molecular sieve catalyst has only a high NO conversion rate, while MnO 2 @ZSM-5 molecular sieve catalyst has high NO and CO conversion rates.

[0090] From the comparison between Example 1 and Examples 8, 9, 10 and Comparative Examples 4, 5, 6, it can be seen that MnO 2 The content of active components affects the NO and CO removal efficiency of the catalyst, among which MnO 2 The catalyst prepared with a mass ratio of 1:5 to ZSM-5 molecular sieve has a higher removal of NO and CO. 2 The catalytic performance of the catalyst prepared when the mass ratio of ZSM-5 molecular sieve is higher or lower than 1:5 is reduced.

[0091] From the comparison between Example 1 and Comparative Example 7, it can be seen that the MnO prepared by the solid phase diffusion method 2 The catalytic performance of @ZSM-5 zeolite catalyst is better than that of the catalyst prepared by hydrothermal method, which indicates that the solid phase diffusion method improves the dispersion of active components and thus improves the catalytic performance.

[0092] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A manganese oxide molecular sieve catalyst, characterized in that: It consists of molecular sieve and manganese oxide, wherein the mass ratio of manganese oxide to molecular sieve is 1:3-1:

9.

2. The manganese oxide molecular sieve catalyst according to claim 1, characterized in that: The manganese oxide is one of α-MnO2, β-MnO2, γ-MnO2, δ-MnO2, Mn2O3 or Mn3O4.

3. The manganese oxide molecular sieve catalyst according to claim 1, characterized in that: The molecular sieve is ZSM-5.

4. The manganese oxide molecular sieve catalyst according to claim 1, characterized in that: The mass ratio of the manganese oxide to the molecular sieve is 1:

5.

5. The manganese oxide molecular sieve catalyst according to claim 1, characterized in that: The manganese oxide molecular sieve catalyst has a pore size of 1.7-3 nm and a specific surface area of ​​300-500 m 2 / g.

6. A method for preparing the manganese oxide molecular sieve catalyst according to any one of claims 1 to 5, characterized in that: The steps include: (1) preparing manganese oxide by a hydrothermal method and setting aside; (2) The manganese oxide and the molecular sieve are mixed and stirred in proportion by a solid phase diffusion method, and then calcined to obtain a manganese oxide molecular sieve catalyst.

7. The method for preparing the manganese oxide molecular sieve catalyst according to claim 6, characterized in that: The solvent used in the solid phase diffusion method is ethanol.

8. The method for preparing the manganese oxide molecular sieve catalyst according to claim 7, characterized in that: In the solid phase diffusion method, the solid-liquid ratio of the solid to the solvent is 1:3-1:5; the stirring temperature is 35-50° C., and the stirring time is 0.5-1.5 h.

9. The method for preparing the manganese oxide molecular sieve catalyst according to claim 6, characterized in that: The calcination temperature is 300-450° C., and the calcination time is 3-6 hours.

10. Use of the manganese oxide molecular sieve catalyst according to any one of claims 1 to 5 in the synergistic removal of NO and CO.

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