A two-stage synergistic catalytic removal of NO x VOCs catalyst and preparation method thereof

Abstract

The present invention discloses a two-stage synergistic catalytic removal of NO x The catalyst and its preparation method are as follows: the catalyst carrier is TiO2, the front section of the catalyst adopts microfluidic electrospinning to control the in-situ generation of praseodymium manganese composite oxide as the front section active component for NO x Reduction, the latter stage uses the impregnation aid to strengthen the impregnation method to load the tin-cerium composite oxide as the latter stage active component for the catalytic oxidation of VOCs. Based on the mass of the carrier, the active component accounts for 4.1% to 7.2% of the carrier mass. The catalyst has high conversion efficiency, strong selectivity, and strong anti-poisoning performance. It can reduce NO in the range of 200 to 400 ° C. x The conversion efficiency of VOCs is greater than 90%, and it has broad market application prospects.

Description

Technical Field

[0001] The present invention provides a two-stage synergistic catalytic removal of NO x The invention relates to a VOCs catalyst and a preparation method thereof, and belongs to the field of environmental protection catalytic materials and air pollution control. Background Art

[0002] Compared with the flue gas emitted by coal-fired power plants, the flue gas composition of biomass boilers is more complex, including NO x And other conventional pollutants, but also contains VOCs and other unconventional pollutants. x VOCs are the main pollutants and are also important precursors to the formation of fine particulate matter and ozone (O3), which can easily cause air pollution such as acid rain, atmospheric haze and photochemical smog. Among them, VOCs have the characteristics of irritation, persistence, high toxicity and photochemical reactivity. x There are more and more research reports on the synergistic removal of NO and VOCs, but the development of catalysts with high efficiency and synergistic performance is still lacking. There are also problems such as unclear synergistic removal mechanism of the two pollutants and easy poisoning of catalysts. Therefore, the development of efficient new catalytic materials has attracted much attention from scientific researchers. x The coordinated control of VOCs is of great significance to the ecological environment.

[0003] Patent (CN115282752A) discloses a pre-oxidation and tempering coupled catalytic low-temperature flue gas NO x In conjunction with the VOCs removal method, a pre-oxidant is used to partially oxidize NO to NO2. The pre-oxidant is easy to decompose, making the NO-containing x The low-temperature flue gas with VOCs is first pre-oxidized, and the NO in the flue gas is partially oxidized to NO2 by pre-oxidation, and then synergistic catalysis is carried out to reduce the NO in the flue gas under the action of ammonia, oxygen and bifunctional catalyst. x This method undoubtedly increases the processing cost through pre-modulation and pre-treatment, is complicated to operate, and has low selectivity for pollutants. Summary of the Invention

[0004] The present invention aims to x A two-stage synergistic catalytic removal of NO was proposed to solve the problem of catalyst existence under the condition of coexistence of flue gas with VOCs. x Another object of the present invention is to provide a method for preparing the VOCs catalyst.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] The catalyst carrier is TiO2, and different active elements are impregnated into both ends of the carrier by impregnation and in-situ spinning, dividing the catalyst reaction section into two parts. The front section of the catalyst adopts microfluidic electrospinning to control the in-situ generation of praseodymium manganese composite oxide as the front section active component for NO x In the reduction stage, the impregnation aid-enhanced impregnation method is used to load tin-cerium composite oxide as the active component in the latter stage for catalytic oxidation of VOCs, making the two reaction stages highly selective and efficient in catalytic performance, achieving the purpose of efficiently treating different pollutants in the front and back stages of the catalyst;

[0007] In the technical solution of the present invention: a two-stage synergistic catalytic removal of NO x The catalyst is characterized in that: the catalyst carrier is TiO2, the front section of the catalyst adopts microfluidic electrospinning to control the in-situ generation of praseodymium manganese composite oxide as the front section active component for NO x Reduction, the latter stage adopts the impregnation method of strengthening impregnation with impregnation aid to load tin-cerium composite oxide as the latter stage active component for catalytic oxidation of VOCs, based on the mass of the carrier, the mass ratio of the active component to the carrier is 4.1% to 7.2%.

[0008] In the technical solution of the present invention, the length of the front section and the rear section of the catalyst are 1-3:1-3.

[0009] In the technical solution of the present invention, based on the mass of the carrier, the praseodymium-manganese composite oxide accounts for 2.5% to 4.2% of the carrier mass, and the tin-cerium composite oxide accounts for 1.6% to 3% of the carrier mass.

[0010] In the technical solution of the present invention, the mass ratio of praseodymium oxide to manganese oxide in the front-stage active component is (22-34): (3-7.6), and the mass ratio of tin oxide to cerium oxide in the back-stage active component is (1-2.5): (1.8-2.7).

[0011] In the technical solution of the present invention: the preparation method of the catalyst is as follows:

[0012] (1) Preparation of catalyst carrier

[0013] TiO2 is added to deionized water and stirred evenly, and then transferred to a hydrothermal reactor for hydrothermal activation. After hydrothermal activation, the TiO2 is taken out and dried. After drying, the TiO2 is crushed and sieved. A binder and deionized water are added and stirred evenly. The TiO2 is placed in an extruder and extruded into a cylindrical shape. The TiO2 is then placed in a muffle furnace and calcined to form a cylindrical catalyst carrier.

[0014] (2) Loading of VOCs catalytic active components

[0015] Add Sn salt and Ce salt to deionized water and stir evenly, then add impregnation aid and stir evenly again to obtain impregnation mixture, then immerse the cylindrical catalyst support obtained in step (1) in the impregnation mixture, the immersion depth being 50% of the length of the cylindrical catalyst support, and after impregnation, place the cylindrical catalyst support in a muffle furnace and calcine to obtain a catalyst loaded with active components in the rear stage;

[0016] (3) NO x Support of catalytically active components

[0017] The high molecular weight polymer is added to an organic solvent and stirred at 70°C, and then Pr salt and Mn salt are added and stirred again to obtain a mixed solution; the rear section of the catalyst loaded with active components obtained in step (2) is wrapped with tin foil, the mixed solution in the reaction process is spun by a microfluidic electrostatic integrated machine, the mixed solution is introduced into the microfluidic electrostatic integrated machine by a microfluidic pump syringe to form a high molecular weight polymer nanofiber containing praseodymium manganese composite oxide, and the high molecular weight polymer nanofiber is wound around the front section of the catalyst, and after high temperature calcination with nitrogen as a protective atmosphere, a two-stage synergistic catalytic removal of NO is finally obtained. x With VOCs catalyst.

[0018] In the above preparation method: the TiO2 described in step (1) is nano-anatase titanium dioxide, and the binder is hydroxymethyl cellulose.

[0019] The mass ratio of TiO2 to deionized water in the hydrothermal activation of step (1) is 1:(4-8).

[0020] The mass ratio of the sieved TiO2, binder and deionized water in step (1) is 10:(0.3-0.5):(2-3).

[0021] The temperature of the hydrothermal activation in step (1) is 180-220° C., and the time of the hydrothermal activation is 6-8 hours; the temperature of the drying is 70-80° C., and the time of the drying is 4-6 hours.

[0022] The mesh size of the crushing and screening in step (1) is 40 to 60 meshes; the roasting temperature is 500 to 600° C., and the roasting time is 4 to 8 hours.

[0023] In the above preparation method: the Sn salt and Ce salt described in step (2) are SnCl4 and Ce(NO3)3 respectively, the impregnation aid is a mixture of citric acid and ethylene glycol, and the mass ratio of Sn salt, Ce salt, citric acid, ethylene glycol and deionized water is (1-2.5):(2-3):(1-2):5:20.

[0024] The impregnation time in step (2) is 1 to 3 hours, the roasting temperature is 500 to 600° C., and the roasting time is 4 to 6 hours.

[0025] In the above preparation method: the Pr salt and Mn salt described in step (3) are PrCl3 and Mn(NO3)2·6H2O respectively, the high molecular polymer is polystyrene, the organic solvent is dichloromethane, and the mass ratio of Pr salt, Mn salt, polystyrene and dichloromethane is (3.2~5):(1~2.5):(20~25):(5~6).

[0026] The gas flow rate of nitrogen in step (3) is (40-60) ml / min, the temperature of high-temperature roasting is 500-600° C., and the time of high-temperature roasting is 4-6 hours.

[0027] The voltage of the microfluidic electrostatic integrated machine described in step (3) is 20kV, and the introduction rate of the microfluidic pump syringe to introduce the mixed liquid into the microfluidic electrostatic integrated machine is 0.5-1.5ml / h.

[0028] Catalyst performance evaluation method: 1 ml of the prepared catalyst was placed in a catalyst performance evaluation reaction device with an inner diameter of 8 mm in the quartz tube. Chlorobenzene was used as a representative substance for VOCs, and NO was used as a representative substance for NO. x Representative substances were tested by introducing simulated gas for activity evaluation. The simulated gas composition was: NO (400ppm), NH3 (400ppm), chlorobenzene (40ppm), O2 (11%), and N2 as carrier gas. The total gas flow rate was 1000mL / min. The catalytic reaction test temperature range was 200-400°C, and the test time was 15 minutes at each temperature point.

[0029] Beneficial effects:

[0030] my country has achieved ultra-low emission purification of conventional pollutants in industrial flue gas. However, with the advancement of clean energy, biomass energy has become the fourth largest energy source in the world. With the extensive use of biomass boilers, the proportion of pollutant emissions has increased year by year, and NO x and VOCs are the main pollutants. x There are more and more research reports on the synergistic removal of NO and VOCs, but the development of catalysts with high efficiency and synergistic performance is still lacking. There are also problems such as unclear synergistic removal mechanism of the two pollutants and easy poisoning of catalysts. Therefore, the development of efficient new catalytic materials has attracted much attention from scientific researchers. x The coordinated control of VOCs is of great significance to the ecological environment.

[0031] A two-stage synergistic catalytic removal of NO prepared by the present inventionx The VOCs catalyst can not only achieve NO x In synergistic removal of VOCs, oxygen vacancies are the primary active sites for the catalytic oxidation of VOCs. Praseodymium and manganese composite oxides possess a high abundance of oxygen vacancies, resulting in higher catalytic efficiency against VOCs. Furthermore, praseodymium exhibits strong resistance to corrosion in air, and its addition can effectively improve the catalyst's corrosion resistance. Tin and cerium oxides provide more acid sites, enhancing the catalyst's reduction performance. Furthermore, the catalyst is adapted to a two-stage structure, resulting in two distinct reaction zones. This results in greater selectivity for pollutants and improved degradation efficiency. Furthermore, the in-situ spinning process increases the volume of the catalyst's front section and forms a tangent with the rear section, creating a turbulent flow zone. Nitrogen generated by the front section passes through this turbulent flow zone, further enhancing the nitrogen purge intensity of the rear section, reducing the amount of poisoning substances adsorbed by the rear section and imparting excellent anti-poisoning properties to the catalyst. Furthermore, the in-situ spinning method allows for continuous and quantitative control of the active component loading on the carrier, ensuring uniform loading of the active components and avoiding issues such as uneven loading and accumulation of active components. The catalyst of the present invention has high conversion efficiency, strong selectivity for pollutants, simple preparation process and broad market application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is the removal rate of NO by the catalyst in Examples 1 to 3 and Comparative Examples 1 to 3;

[0033] Figure 2 is the removal rate of chlorobenzene by the catalyst in Examples 1 to 3 and Comparative Examples 1 to 3; DETAILED DESCRIPTION

[0034] The present invention will be further described below with reference to the embodiments, but the protection scope of the present invention is not limited thereto:

[0035] The nano-TiO2 described in the embodiment is nano-anatase titanium dioxide, which can be purchased from http: / / www.wq-reagent.com / product / PNO0331973.html

[0036] Example 1

[0037] (1) Preparation of catalyst carrier

[0038] 50g of nano-TiO2 was added to 200ml of deionized water and stirred evenly, then transferred to a hydrothermal reactor and hydrothermally activated at 200°C for 6h. After hydrothermal activation, it was taken out and dried at 70°C for 4h. After drying, it was crushed and sieved out with a sieve to remove the 40-60 mesh portion. 10g of it was weighed and added to 0.3g of hydroxymethyl cellulose in 5ml of deionized water and stirred evenly. The mixture was then extruded into a cylindrical shape in an extruder and calcined in a muffle furnace at 500°C for 4h to obtain a cylindrical catalyst carrier.

[0039] (2) Loading of VOCs catalytic activity

[0040] 0.1 g of SnCl4 and 0.2 g of Ce(NO3)3 were added to 2 ml of deionized water and stirred evenly, and then 0.2 g of citric acid and 0.5 g of ethylene glycol were added and stirred evenly again to obtain an impregnation mixture, and then the cylindrical catalyst support prepared in step (1) was immersed in the impregnation mixture for 2 h, and the immersion depth was 50% of the length of the cylindrical catalyst support; after the impregnation, the cylindrical catalyst support was placed in a muffle furnace and calcined at 500° C. for 4 h to obtain a catalyst loaded with active components in the rear section;

[0041] (3) NO x Catalytically active loading

[0042] At 70°C, 2g of polystyrene was added to 0.5g of dichloromethane and stirred evenly, and then 0.32g of PrCl3 and 0.1g of Mn(NO3)2·6H2O were added and stirred again to obtain a mixed solution; the rear section of the catalyst loaded with active components obtained in step (2) was wrapped with tin foil, the mixed solution in the reaction process was spun by a microfluidic electrostatic integrated machine, and the mixed solution was introduced into the microfluidic electrostatic integrated machine using a microfluidic pump syringe to form a polymer nanofiber containing praseodymium manganese composite oxide, and the polymer nanofiber was wrapped around the front section of the catalyst, the voltage of the microfluidic electrostatic integrated machine was 20kV, and the introduction rate of the microfluidic pump syringe to introduce the mixed solution into the microfluidic electrostatic integrated machine was 1ml / h. Then, nitrogen gas with a flow rate of 40ml / min was used as a protective atmosphere, and after high temperature roasting at 500°C for 4h, a two-stage synergistic catalytic removal of NO was finally obtained. x With VOCs catalyst.

[0043] (4) Catalytic activity test

[0044] One milliliter of the prepared catalyst was placed in a catalyst performance evaluation reactor containing an 8mm inner diameter quartz tube. Simulated gas was introduced for activity evaluation. The simulated gas composition consisted of NO (400 ppm), NH3 (400 ppm), chlorobenzene (40 ppm), O2 (11%), and N2 as a carrier gas, with a total gas flow rate of 1000 mL / min. The catalytic reaction was tested at a temperature range of 200-400°C, with each temperature maintained for 15 minutes. Test results showed that within the 200-400°C temperature range, NO removal efficiencies ranged from a minimum of 95.7% to a maximum of 100%. Chlorobenzene removal efficiencies ranged from a minimum of 92.6% to a maximum of 97.4%.

[0045] Example 2

[0046] (1) Preparation of catalyst carrier

[0047] 50g of nano-TiO2 was added to 200g of deionized water and stirred evenly, then transferred to a hydrothermal reactor and hydrothermally activated at 200°C for 6h. After hydrothermal activation, the mixture was taken out and dried at 70°C for 4h. After drying, the mixture was crushed and sieved out with a sieve to remove the 40-60 mesh portion. 10g of the mixture and 0.3g of hydroxymethyl cellulose were weighed and added to 5g of deionized water and stirred evenly. The mixture was then extruded into a cylindrical shape in an extruder and calcined in a muffle furnace at 500°C for 4h to obtain a cylindrical catalyst support.

[0048] (2) Loading of VOCs catalytic activity

[0049] 0.2 g of SnCl4 and 0.25 g of Ce(NO3)3 were added to 4 g of deionized water and stirred evenly, and then 0.4 g of citric acid and 1 g of ethylene glycol were added and stirred evenly again to obtain an impregnation mixture, and then the cylindrical catalyst support prepared in step (1) was immersed in the impregnation mixture for 2 h, and the immersion depth was 50% of the length of the cylindrical catalyst support; after the impregnation, the cylindrical catalyst support was placed in a muffle furnace and calcined at 500° C. for 4 h to obtain a catalyst loaded with active components in the rear section;

[0050] (3) NO x Catalytically active loading

[0051] At 70°C, 2.4g of polystyrene was added to 0.6g of dichloromethane and stirred evenly, and then 0.4g of PrCl3 and 0.2g of Mn(NO3)2·6H2O were added and stirred again to obtain a mixed solution; the rear section of the catalyst loaded with active components obtained in step (2) was wrapped with tin foil, the mixed solution in the reaction process was spun by a microfluidic electrostatic integrated machine, and the mixed solution was introduced into the microfluidic electrostatic integrated machine using a microfluidic pump syringe to form a polymer nanofiber containing praseodymium manganese composite oxide, and the polymer nanofiber was wrapped around the front section of the catalyst. The voltage of the microfluidic electrostatic integrated machine was 20kV, and the introduction rate of the microfluidic pump syringe to introduce the mixed solution into the microfluidic electrostatic integrated machine was 1ml / h. Then, nitrogen with a flow rate of 40ml / min was used as a protective atmosphere, and after high temperature roasting at 500°C for 4h, a two-stage synergistic catalytic removal of NO was finally obtained. x With VOCs catalyst.

[0052] (4) Catalytic activity test

[0053] One milliliter of the prepared catalyst was loaded into a catalyst performance evaluation reactor containing an 8mm inner diameter quartz tube. Simulated gas was introduced for activity evaluation. The simulated gas composition consisted of NO (400 ppm), NH3 (400 ppm), chlorobenzene (40 ppm), O2 (11%), and N2 as a carrier gas, with a total gas flow rate of 1000 mL / min. The catalytic reaction was tested at a temperature range of 200-400°C, with each temperature maintained for 15 minutes. Test results showed that within the 200-400°C temperature range, NO removal efficiencies ranged from a minimum of 96.7% to a maximum of 100%. Chlorobenzene removal efficiencies ranged from a minimum of 89.6% to a maximum of 94.4%.

[0054] Example 3

[0055] (1) Preparation of catalyst carrier

[0056] 50g of nano-TiO2 was added to 200ml of deionized water and stirred evenly, then transferred to a hydrothermal reactor and hydrothermally activated at 200°C for 6h. After hydrothermal activation, it was taken out and dried at 70°C for 4h. After drying, it was crushed and sieved out with a sieve to remove the 40-60 mesh portion. 10g of it was weighed and added to 0.3g of hydroxymethyl cellulose in 5ml of deionized water and stirred evenly. The mixture was then extruded into a cylindrical shape in an extruder and calcined in a muffle furnace at 500°C for 4h to obtain a cylindrical catalyst carrier.

[0057] (2) Loading of VOCs catalytic activity

[0058] 0.25 g of SnCl4 and 0.3 g of Ce(NO3)3 were added to 5 g of deionized water and stirred evenly, and then 0.5 g of citric acid and 1.25 g of ethylene glycol were added and stirred evenly again to obtain an impregnation mixture, and then the cylindrical catalyst support prepared in step (1) was immersed in the impregnation mixture for 2 h, and the immersion depth was 50% of the length of the cylindrical catalyst support; after the impregnation, the cylindrical catalyst support was placed in a muffle furnace and calcined at 500° C. for 4 h to obtain a catalyst loaded with active components in the rear section;

[0059] (3) NO x Catalytically active loading

[0060] At 70°C, 2.4g of polystyrene was added to 0.6g of dichloromethane and stirred evenly, and then 0.12g of PrCl3 and 0.06g of Mn(NO3)2·6H2O were added and stirred again to obtain a mixed solution; the rear section of the catalyst loaded with active components obtained in step (2) was wrapped with tin foil, the mixed solution in the reaction process was spun by a microfluidic electrostatic integrated machine, and the mixed solution was introduced into the microfluidic electrostatic integrated machine using a microfluidic pump syringe to form a polymer nanofiber containing praseodymium manganese composite oxide, and the polymer nanofiber was wrapped around the front section of the catalyst. The voltage of the microfluidic electrostatic integrated machine was 20kV, and the introduction rate of the microfluidic pump syringe to introduce the mixed solution into the microfluidic electrostatic integrated machine was 1ml / h. Then, nitrogen with a flow rate of 40ml / min was used as a protective atmosphere, and after calcination at 500°C for 4h, a two-stage synergistic catalytic removal of NO was finally obtained. x With VOCs catalyst.

[0061] (4) Catalytic activity test

[0062] One milliliter of the prepared catalyst was loaded into a catalyst performance evaluation reactor containing an 8mm inner diameter quartz tube. Simulated gas was introduced for activity evaluation. The simulated gas composition consisted of NO (400 ppm), NH3 (400 ppm), chlorobenzene (40 ppm), O2 (11%), and N2 as a carrier gas, with a total gas flow rate of 1000 mL / min. The catalytic reaction was tested at a temperature range of 200-400°C, with each temperature maintained for 15 minutes. Test results showed that within the 200-400°C temperature range, the NO removal efficiency ranged from a minimum of 94.7% to a maximum of 100%. The chlorobenzene removal efficiency ranged from a minimum of 88.1% to a maximum of 93.4%.

[0063] Comparative Example 1

[0064] (1) Preparation of catalyst carrier

[0065] The conditions are the same as step (1) in Example 1

[0066] (2) Loading of VOCs catalytic activity

[0067] No SnCl4 was added, and other conditions were the same as step (2) in Example 1;

[0068] (3) NO x Catalytically active loading

[0069] The conditions are the same as step (3) in Example 1

[0070] (4) Catalytic activity test

[0071] The test conditions were the same as those in step (4) of Example 1. The test results showed that within the temperature range of 200-400°C, the NO removal efficiency was as low as 70.1% and as high as 87.3%. The chlorobenzene removal efficiency was as low as 63.6% and as high as 74.4%.

[0072] (5) Contrast effect

[0073] Compared with Example 1, SnCl4 was not added to the loading of VOCs catalytic activity in step (2), and the NO removal effect of the obtained catalyst did not show a significant decrease, while the degradation efficiency of chlorobenzene decreased seriously. Analysis showed that the reason may be that the lack of Sn oxide leads to insufficient active sites of the catalyst, resulting in a decrease in the catalyst's catalytic VOCs activity. The undegraded VOCs will be adsorbed on the catalyst, further leading to a decrease in the catalyst's catalytic oxidation performance for chlorobenzene.

[0074] Comparative Example 2

[0075] (1) Preparation of catalyst carrier

[0076] The conditions are the same as step (1) in Example 1

[0077] (2) Loading of VOCs catalytic activity

[0078] The conditions are the same as step (2) in Example 1;

[0079] (3) NO x Catalytically active loading

[0080] SnCl4 and Ce(NO3)3 were replaced with PrCl3 and Mn(NO3)2·6H2O, and other conditions were the same as those in step (2) of Example 1, and this step was completed by the same impregnation method;

[0081] (4) Catalytic activity test

[0082] The test conditions were the same as those in step (4) of Example 1. The test results showed that within the temperature range of 200-400°C, the NO removal efficiency was as low as 64.7% and as high as 74.3%. The chlorobenzene removal efficiency was as low as 83.2% and as high as 91.4%.

[0083] (5) Contrast effect

[0084] Compared with Example 1, NO x In the loading of catalytic activity (3), the impregnation method is used to load PrCl3 and Mn(NO3)2·6H2O onto the front section of the catalyst. There is no cross-sectional change between the front section and the rear section of the catalyst, the turbulent airflow zone disappears, the nitrogen reduced from the front section of the catalyst has a poor purge effect on the rear section of the catalyst, the anti-poisoning performance of the catalyst decreases, and the catalyst activity decreases. Moreover, under the condition of loading the same active center, the catalyst prepared by the impregnation method has a worse NO removal effect than the catalyst prepared by the in-situ spinning method.

[0085] Comparative Example 3

[0086] (1) Preparation of catalyst carrier

[0087] The step of hydrothermal activation of nano-TiO2 is removed, and other conditions are the same as step (1) in Example 1.

[0088] (2) Loading of VOCs catalytic activity

[0089] The conditions are the same as step (2) in Example 1;

[0090] (3) NO x Catalytically active loading

[0091] The conditions are the same as step (3) in Example 1;

[0092] (4) Catalytic activity test

[0093] The test conditions were the same as those in step (4) of Example 1. The test results showed that within the temperature range of 200-400°C, the NO removal efficiency was as low as 54.7% and as high as 72.3%. The chlorobenzene removal efficiency was as low as 81.6% and as high as 87.4%.

[0094] (5) Contrast effect

[0095] Compared with Example 1, the nano-TiO2 was not hydrothermally activated in the preparation of the catalyst carrier in step (1), which may result in low activity of the prepared catalyst carrier, and the activity of the loaded active centers is also reduced. The catalytic activity of the catalyst is reduced, thereby showing a downward trend in the degradation efficiency of both pollutants.

Claims

1. A two-stage synergistic catalytic removal of NO x VOCs catalyst, characterized by: The catalyst carrier is TiO2, and the front section of the catalyst uses microfluidic electrospinning to control the in-situ generation of praseodymium manganese composite oxide as the front section active component for NO x Reduction, in the latter stage, the impregnation method is enhanced by an impregnation aid to load the tin-cerium composite oxide as the active component for the catalytic oxidation of VOCs. Based on the mass of the carrier, the active component accounts for 4.1% to 7.2% of the carrier mass; based on the mass of the carrier, the praseodymium-manganese composite oxide accounts for 2.5% to 4.2% of the carrier mass, and the tin-cerium composite oxide accounts for 1.6% to 3% of the carrier mass; The preparation method of the catalyst is as follows: (1) Preparation of catalyst carrier TiO2 is added to deionized water and stirred evenly, and then transferred to a hydrothermal reactor for hydrothermal activation. After hydrothermal activation, the mixture is taken out and dried, and then crushed and sieved after drying. A binder and deionized water are added and stirred evenly, and the mixture is placed in an extruder to be extruded into a cylindrical shape, and then placed in a muffle furnace for calcination to form a cylindrical catalyst carrier; wherein the hydrothermal activation temperature is 180-220° C., and the hydrothermal activation time is 6-8 hours; (2) Loading of VOCs catalytic active components Add Sn salt and Ce salt to deionized water and stir evenly, then add impregnation aid and stir evenly again to obtain impregnation mixture, then impregnate the cylindrical catalyst support obtained in step (1) into the impregnation mixture, and after impregnation, place the cylindrical catalyst support in a muffle furnace and calcine to obtain a catalyst loaded with active components in the rear stage; (3) NO x Support of catalytically active components Adding a high molecular weight polymer to an organic solvent and stirring evenly at 60-80°C, then adding Pr salt and Mn salt and stirring evenly again to obtain a mixed solution; wrapping the catalyst portion loaded with active components obtained in step (2) with tin foil, spinning the mixed solution during the reaction process through a microfluidic electrostatic integrated machine, introducing the mixed solution into the microfluidic electrostatic integrated machine using a microfluidic pump syringe to form a high molecular weight polymer nanofiber containing praseodymium manganese composite oxide, and winding the high molecular weight polymer nanofiber around the catalyst front section, and finally obtaining a two-stage synergistic catalytic removal of NO after high temperature calcination with nitrogen as a protective atmosphere. x With VOCs catalyst.

2. The catalyst according to claim 1, characterized in that: The lengths of the front section and the rear section of the catalyst are 1~3:1~3.

3. The catalyst according to claim 1, characterized in that: The mass ratio of praseodymium oxide to manganese oxide in the front-stage active component is (3-9):1, and the mass ratio of tin oxide to cerium oxide in the back-stage active component is 1:(1-3).

4. The catalyst according to claim 1, characterized in that: The conditions for step (1) are as follows: The TiO2 is nano-anatase titanium dioxide, and the binder is hydroxymethyl cellulose; The mass ratio of TiO2 to binder after sieving is 10:(0.1~1); The drying temperature is 70-80°C and the drying time is 4-6 hours; The mesh number of the crushing and screening is 40-60 meshes; the roasting temperature is 500-600° C., and the roasting time is 4-8 hours.

5. The catalyst according to claim 1, characterized in that: The Sn salt and Ce salt described in step (2) are SnCl4 and Ce(NO3)3 respectively, and the impregnation aid is a mixture of citric acid and ethylene glycol; The mass ratio of Sn salt, Ce salt, citric acid and ethylene glycol is (1~2.5):(1~3):(1~2):5; The impregnation time in step (2) is 1 to 3 hours, the roasting temperature is 500 to 600° C., and the roasting time is 4 to 6 hours.

6. The catalyst according to claim 1, characterized in that: The Pr salt and Mn salt described in step (3) are PrCl3 and Mn(NO3)2·6H2O respectively, the polymer is polystyrene, and the organic solvent is dichloromethane; The mass ratio of Pr salt, Mn salt, polystyrene and dichloromethane is (1-5): (1-2.5): (10-25): (3-6); The nitrogen gas flow rate in step (3) is (40-60) ml / min, the high-temperature roasting temperature is 500-600°C, and the high-temperature roasting time is 4-6 hours; The voltage of the microfluidic electrostatic integrated machine described in step (3) is 20 kV, and the introduction rate of the microfluidic pump syringe to introduce the mixed liquid into the microfluidic electrostatic integrated machine is 0.5~1.5 ml / h.

7. The catalyst according to claim 1 is used as a catalyst for removing NO x Applications related to VOCs.

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