Preparation method of modified MnCeTiOx catalyst and application of the catalyst in synergistic denitration and VOCs removal

Abstract

The application discloses a preparation method of a modified MnCeTiOx catalyst and application of the modified MnCeTiOx catalyst in synergistic denitration and VOCs removal, and belongs to the technical field of environmental catalysis. The preparation method is as follows: cerium salt and a titanium source precursor are added into deionized water and stirred uniformly, ammonia water is added dropwise to adjust the pH value, and stirring is continued to form a suspension liquid; the suspension liquid is left to stand and stratified, the supernatant is removed, the precipitate is centrifuged and separated, and washing is performed until the precipitate is neutral; and the precipitate is dried and calcined to obtain a CeTiOx catalyst; a manganese salt solution is poured into the CeTiOx catalyst, and heating and stirring are performed until the water is completely evaporated; and drying and calcining are performed to obtain a MnCeTiOx catalyst; and the MnCeTiOx catalyst is subjected to plasma modification treatment to obtain a modified MnCeTiOx catalyst. The method is simple and feasible, and time consumption is small; while the cost of the catalyst is low, the performance of the catalyst in synergistic removal of NOx and VOCs under the condition of coexistence of SO2 is improved.

Description

Technical Field

[0001] This invention belongs to the field of environmental catalysis technology, specifically relating to a method for preparing a modified MnCeTiOx catalyst and its application in synergistic denitrification and VOCs removal. Background Technology

[0002] Nitrogen oxides (NOx) and volatile organic compounds (VOCs) are the main contributors to ozone and PM2.5 formation. 2.5 NOx and VOCs are two important precursors. With increasingly stringent environmental regulations, the synergistic reduction of NOx and VOCs has become a top priority in my country's air pollution control. Selective catalytic reduction (SCR) technology is currently the most mainstream and mature technology for industrial flue gas denitrification, and its core technology lies in high-performance denitrification catalysts. However, actual industrial flue gas (such as coke oven gas and biomass boiler gas) often has a complex composition, containing not only particulate matter and NOx, but also multiple air pollutants such as VOCs and SOx. Traditional SCR denitrification catalysts only target the single removal of NOx, making it difficult to meet the practical needs of synergistic treatment of multiple pollutants. Therefore, the development of multifunctional catalysts that can simultaneously and efficiently remove NOx and VOCs has become a research hotspot in the field of environmental catalysis.

[0003] MnCeTiOx catalysts show promise in NH3-SCR denitrification and VOCs catalytic oxidation. Chinese invention patent CN107649121A discloses a method for modifying a manganese-based denitrification catalyst and a modified manganese-based denitrification catalyst and its preparation method. The modification method involves placing the manganese-based denitrification catalyst in a medium-barrier tube, introducing reactant gas into the reactor, and then subjecting it to plasma treatment. The resulting modified manganese-based denitrification catalyst has low loading, low cost, and good catalytic effect; however, the support is one of CeO2, ZrO2, Al2O3, activated carbon, or molecular sieve, and CeTiOx support is not mentioned. Furthermore, under SO2 coexistence conditions in flue gas, the Mn component is easily deactivated by sulfation, resulting in poor NOx removal efficiency. However, existing plasma modification studies mostly focus on catalysts for single pollutant removal, and there are few reports on DBD modification of MnCeTiOx catalysts for synergistic removal of NOx and VOCs under sulfur-containing atmospheres.

[0004] Therefore, there is an urgent need in the field for a method to prepare a modified MnCeTiOx catalyst in order to improve the activity and effect of the catalyst in synergistic removal of NOx and VOCs under SO2 coexistence conditions. Summary of the Invention

[0005] In view of this, the present invention proposes a method for preparing a modified MnCeTiOx catalyst and its application in synergistic denitrification and VOCs removal. The method is simple, feasible, and time-saving. While ensuring low catalyst cost, it improves the performance of the catalyst in synergistic removal of NOx and VOCs under SO2 coexistence conditions.

[0006] To achieve the above objectives, the present invention first provides a method for preparing a modified MnCeTiOx catalyst, comprising the following preparation steps:

[0007] S1, cerium salt and titanium source precursor are added to deionized water and stirred until homogeneous; then ammonia water is added dropwise to adjust the pH value, and stirring is continued to form a homogeneous suspension. After standing and allowing natural separation, the supernatant is removed, the precipitate is centrifuged, washed until neutral, and then dried and calcined to obtain CeTiOx catalyst.

[0008] S2, the CeTiOx catalyst obtained in S1 and the manganese salt are added to deionized water, heated and stirred until the water is completely evaporated, and then dried and calcined to obtain the MnCeTiOx catalyst.

[0009] S3. The MnCeTiOx catalyst obtained in S2 is placed in a dielectric barrier discharge low-temperature plasma treatment device, and gas is introduced into the treatment device to carry out plasma modification treatment, thereby obtaining a DBD plasma-modified MnCeTiOx catalyst.

[0010] Preferably, the cerium salt in step S1 is one or more of cerium nitrate, cerium acetate, cerium sulfate, and cerium chloride; the titanium source precursor is one or more of tetrabutyl titanate, tetraisopropyl titanate, titanium tetrachloride, and titanium oxysulfate; the molar ratio of Ce:Ti in the cerium salt and the titanium source precursor is 30:1-10:1; the volume ratio of the cerium salt to deionized water is 0.01-0.05 mol:100 mL; and the pH adjustment is to adjust the pH to 8-11.

[0011] Preferably, the drying temperature in step S1 is 80-110℃ and the time is 12-24h; the calcination temperature is 500℃-600℃ and the time is 2-4h.

[0012] Preferably, the manganese salt in step S2 is one or more of manganese nitrate, manganese acetate, manganese sulfate, and manganese chloride; the ratio of the manganese salt to deionized water is 0.01-0.05 mol:100 mL; and the molar ratio of CeTiOx catalyst to Ce:Mn element in manganese salt is 20:1-5:1.

[0013] Preferably, the drying temperature in step S2 is 80-110℃ and the time is 12-24h; the calcination temperature is 500℃-600℃ and the time is 2-4h.

[0014] Preferably, the gas in step S3 is N2, or one or a mixture of several gases including O2, Ar, H2-Ar, and air; the gas flow rate is 20-100 mL / min; the dielectric barrier discharge low-temperature plasma treatment device is either a coaxial cylindrical dielectric barrier type or a parallel plate dielectric barrier type; the discharge power of the plasma modification treatment is 10-30 W; and the treatment time is 5-30 min.

[0015] The present invention also provides an application of the modified MnCeTiOx catalyst prepared by the method described above in flue gas treatment.

[0016] Preferably, the application is in flue gas denitrification, and the catalyst operates in a temperature range of 100-250℃.

[0017] More preferably, the application is for the synergistic denitrification and VOCs removal of SO2-containing flue gas; the SO2 concentration of the inlet flue gas is ≤100ppm; the denitrification rate reaches 90%-100%; and the VOCs removal rate reaches 90%-100%.

[0018] Compared with the prior art, the present invention has the following significant advantages: (1) The preparation method of DBD plasma modified MnCeTiOx catalyst of the present invention, by systematically controlling the plasma treatment power and treatment time, utilizes the high-energy electrons and active particles generated by the plasma to etch the catalyst surface, improve the dispersion of active components MnOx and CeO2 on TiO2 support, enhance the interaction between metal and support, and introduce lattice defects and surface oxygen vacancies to precisely optimize the surface properties and active site distribution of the catalyst. The modification conditions are simple, the operation is easy, the energy consumption is low, and no chemical reagents need to be added.

[0019] (2) The modified MnCeTiOx catalyst described in this invention is applied to the synergistic denitrification and VOCs removal. Under the conditions of working temperature of 100-250℃ and coexistence of SO2, it can still maintain high NOx and toluene synergistic removal activity, which overcomes the technical problem of traditional manganese-based catalysts being easily deactivated by sulfation under sulfur-containing atmosphere. It is suitable for the application scenario of synergistic treatment of multiple pollutants in industrial flue gas. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0021] Figure 1 This is a comparison chart showing the NOx removal efficiency of modified and unmodified MnCeTiOx catalysts.

[0022] Figure 2 This is a comparison chart showing the NOx removal efficiency of MnCeTiOx catalysts under different modified atmospheres.

[0023] Figure 3 The effect of modified MnCeTiOx catalyst on the synergistic removal of NOx and toluene when SO2 coexists is shown in the figure. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Before describing the technical solution of this invention in detail, it is necessary to explain the source of the raw materials and reagents used and the experimental methods as follows to ensure that those skilled in the art can fully understand and reproduce this invention.

[0026] Unless otherwise specified, experimental conditions not mentioned in the examples were performed according to conventional methods or literature reports; all raw materials, reagents, and equipment used were commercially available conventional products. The following examples are for illustrative purposes only and do not constitute a limitation on the scope of protection. Any improvements or equivalent substitutions made based on the technical solutions of this invention shall fall within the scope of protection of this invention.

[0027] The formula for calculating the denitrification rate is:

[0028] The formula for calculating the toluene removal rate is:

[0029] Example 1 Preparation of modified MnCeTiOx catalyst S1. Preparation of CeTiOx support: Weigh 0.01 mol of cerium nitrate hydrate (Ce(NO3)3·6H2O) and 0.0005 mol of tetrabutyl titanate according to a Ce:Ti molar ratio of 20:1. Dissolve both in 40 mL of deionized water and stir magnetically for 1 h at room temperature until homogeneous, obtaining a clear and transparent mixed solution. Then, add ammonia dropwise as an alkaline precipitant in a fume hood until the pH reaches 9. Continue stirring for 2 h to form a uniform milky white suspension. Seal the beaker with plastic wrap and let it stand for 24 h to allow for natural stratification and complete precipitation. Remove the supernatant, centrifuge the precipitate, and wash it successively with deionized water and ethanol until the pH is neutral. Place the precipitate in an oven and dry at 90 °C for 24 h, then calcine it in a muffle furnace at 550 °C for 3 h to obtain the CeTiOx support.

[0030] S2, Preparation of MnCeTiOx catalyst: Weigh 0.001 mol of manganese nitrate according to a Ce:Mn molar ratio of 10:1. Add the manganese nitrate and the CeTiOx obtained in S1 to 5 ml of deionized water to form a solution. Heat and stir at 80 °C until the water is completely evaporated, then place in an oven and dry at 100 °C for 12 h. Calcine the dried sample in a muffle furnace at 550 °C for 3 h to obtain the MnCeTiOx catalyst.

[0031] S3, Modification Treatment: 1g of the prepared MnCeTiOx catalyst was placed in the discharge region of a dielectric barrier discharge reactor. N2 was introduced into the reactor as a carrier gas at a flow rate of 40mL / min. The plasma power supply was turned on, the discharge power was adjusted to 20W, and the treatment time was 10min to obtain the DBD plasma-modified MnCeTiOx catalyst.

[0032] Applications of denitrification DBD plasma-modified MnCeTiOx catalyst was placed in a specific reaction tube. After adsorption saturation, NOx decomposition was carried out in the range of 100-350℃. The NOx concentration at the reactor outlet at different temperatures was detected using a flue gas analyzer. The simulated flue gas composition was: 500ppm NH3, 500ppm NO, 7% O2, with N2 as the balance gas, and the total flue gas flow rate was 500mL / min.

[0033] Experimental results are as follows Figure 1 As shown, the modified catalyst exhibits superior NOx removal rates compared to the unmodified catalyst in the temperature range of 100–250 °C. Specifically, at 100 °C, the modified catalyst achieves nearly 100% NOx removal, an increase of almost 38% compared to the unmodified catalyst. The NOx removal rate remains at 100% at both 150 °C and 200 °C, demonstrating excellent low-temperature denitrification activity. This indicates that DBD plasma modification can significantly improve the low-temperature NH3-SCR performance of the MnCeTiOx catalyst.

[0034] The DBD plasma modification method for MnCeTiOx catalyst described in this embodiment employs low-temperature plasma treatment, utilizing high-energy electrons and active particles to physically etch and chemically modify the catalyst surface. This promotes the directional migration and redispersion of MnOx and CeO2 active components on the TiO2 support, enhancing the interfacial interaction between the active components and the support, and introducing surface oxygen vacancies and lattice defects. Consequently, it significantly improves the low-temperature NH3-SCR denitrification activity of the catalyst. Furthermore, the modification conditions are simple, the operation is convenient, the energy consumption is low, no chemical reagents are required, and there is no secondary pollution. Compared with the unmodified catalyst, the low-temperature denitrification effect is significantly improved.

[0035] The modified MnCeTiOx catalyst described in this embodiment of the invention uses TiO2 as a support and CeO2 and MnOx as active components. Through DBD plasma modification treatment, it exhibits excellent NOx removal performance in a wide temperature window of 100~250℃. Moreover, the preparation method is simple, time-saving, and low-cost, making it suitable for industrial flue gas denitrification applications.

[0036] Example 2 Preparation of modified MnCeTiOx catalyst S1. Preparation of CeTiOx support: 0.01 mol of cerium nitrate hydrate (Ce(NO3)3·6H2O) and 0.0005 mol of tetrabutyl titanate were weighed according to a Ce:Ti molar ratio of 20:1. Both were dissolved together in 40 mL of deionized water and magnetically stirred at room temperature for 1.5 h until homogeneous, yielding a clear and transparent mixed solution. Subsequently, ammonia was added dropwise as an alkaline precipitant in a fume hood until the pH reached 9. Stirring continued for 2 h to form a uniform milky white suspension. The beaker was sealed with plastic wrap and allowed to stand for 20 h to allow for natural stratification and complete precipitation. The supernatant was removed, and the precipitate was centrifuged and washed successively with deionized water and ethanol until the pH was neutral. The resulting precipitate was dried in an oven at 100 °C for 20 h, and then calcined in a muffle furnace at 550 °C for 3 h to obtain the CeTiOx support.

[0037] S2, Preparation of MnCeTiOx catalyst: Weigh 0.001 mol of manganese nitrate according to a Ce:Mn molar ratio of 10:1. Add manganese nitrate and CeTiOx to 5 ml of deionized water to form a solution. Heat and stir at 80℃ until the water is completely evaporated, then place in an oven and dry at 90℃ for 16 h. Calcine the dried sample in a muffle furnace at 550℃ for 3 h to obtain the MnCeTiOx catalyst.

[0038] S3, Modification Treatment: 1g of the prepared MnCeTiOx catalyst was placed in the discharge region of a dielectric barrier discharge reactor. Ar was introduced into the reactor as a carrier gas at a flow rate of 40mL / min. The plasma power supply was turned on, the discharge power was adjusted to 20W, and the treatment time was 10min to obtain the DBD plasma-modified MnCeTiOx catalyst.

[0039] Applications of denitrification A DBD plasma-modified MnCeTiOx catalyst was placed in a specific reactor. After adsorption saturation, NOx decomposition was carried out within the temperature range of 100-350℃. The NOx concentration at the reactor outlet was detected using a flue gas analyzer at different temperatures. The simulated flue gas composition was: 500 ppm NH3, 500 ppm NO, 7% O2, with N2 as the balance gas, and a total flue gas flow rate of 500 mL / min.

[0040] Experimental results are as follows Figure 2 As shown, the modified catalyst exhibits superior NOx removal rates compared to the unmodified catalyst in the range of 100–200 °C, reaching nearly 100% at 150 °C and 200 °C, demonstrating excellent low-temperature denitrification activity. This indicates that DBD plasma modification can significantly improve the low-temperature NH3-SCR performance of the MnCeTiOx catalyst.

[0041] The DBD plasma modification method for MnCeTiOx catalyst described in this embodiment employs low-temperature plasma treatment, utilizing high-energy electrons and active particles to physically etch and chemically modify the catalyst surface. This promotes the directional migration and redispersion of MnOx and CeO2 active components on the TiO2 support, enhancing the interfacial interaction between the active components and the support, introducing surface oxygen vacancies and lattice defects, thereby significantly improving the low-temperature NH3-SCR denitrification activity of the catalyst. Furthermore, the modification conditions are simple, the operation is convenient, energy consumption is low, no chemical reagents are required, and there is no secondary pollution. Compared with the unmodified catalyst, the low-temperature denitrification effect is significantly improved. The modified MnCeTiOx catalyst described in this embodiment, using TiO2 as the support and CeO2 and MnOx as the active components, exhibits excellent NOx removal performance within the range of 100~200℃ after DBD plasma modification treatment. Moreover, the preparation method is simple, time-saving, and low-cost, making it suitable for industrial flue gas denitrification applications.

[0042] Example 3 Preparation of modified MnCeTiOx catalyst S1. Preparation of CeTiOx support: 0.02 mol of cerium nitrate (Ce(NO3)3·6H2O) and 0.001 mol of tetrabutyl titanate were weighed according to a Ce:Ti molar ratio of 20:1. Both were dissolved together in 80 mL of deionized water and magnetically stirred at room temperature for 1 h until homogeneous, yielding a clear and transparent mixed solution. Subsequently, ammonia was added dropwise as an alkaline precipitant in a fume hood until the pH reached 9. Stirring continued for 2 h to form a uniform milky white suspension. The beaker was sealed with plastic wrap and allowed to stand for 20 h to allow for natural stratification and complete precipitation. The supernatant was removed, and the precipitate was centrifuged and washed successively with deionized water and ethanol until the pH was neutral. The resulting precipitate was dried in an oven at 90 °C for 20 h, and then calcined in a muffle furnace at 550 °C for 3 h to obtain the CeTiOx support.

[0043] S2, Preparation of MnCeTiOx catalyst: Weigh 0.002 mol of manganese nitrate according to a Ce:Mn molar ratio of 10:1. Add manganese nitrate and CeTiOx to 10 ml of deionized water to form a solution. Heat and stir at 80 °C until the water is completely evaporated, then place in an oven and dry at 110 °C for 10 h. Calcine the dried sample in a muffle furnace at 550 °C for 3 h to obtain the MnCeTiOx catalyst.

[0044] S3, Modification Treatment: 1g of the prepared MnCeTiOx catalyst was placed in the discharge region of a dielectric barrier discharge reactor. N2 was introduced into the reactor as a carrier gas at a flow rate of 40mL / min. The plasma power supply was turned on, the discharge power was adjusted to 20W, and the treatment time was 10min to obtain the DBD plasma-modified MnCeTiOx catalyst.

[0045] Application of synergistic denitrification and VOCs removal in SO2-containing environments DBD plasma-modified MnCeTiOx catalyst was placed in a specific reaction tube. After adsorption saturation, an experiment was conducted at 200℃ to simultaneously remove NOx and toluene from SO2-containing flue gas. The NOx concentration at the reactor outlet was measured using a flue gas analyzer at different temperatures, and the toluene outlet concentration was measured using gas chromatography. The simulated flue gas composition was: 500 ppm NH3, 500 ppm NO, 7% O2, with N2 as the balance gas, 50 ppm toluene, and 50 ppm SO2. The total flue gas flow rate was 500 mL / min.

[0046] Experimental results are as follows Figure 3As shown, the optimal MnCeTiOx catalyst modified by DBD was subjected to a 9-hour sulfur resistance synergistic performance test under simulated flue gas conditions containing 50 ppm SO2 and 50 ppm toluene at 200℃. The results showed that the NOx removal rate remained above 95% throughout the test, and the toluene removal rate remained stable. This indicates that the catalyst possesses excellent resistance to SO2 poisoning and stable synergistic removal of NOx and toluene under sulfur-containing atmospheres. The introduction of SO2 did not significantly inhibit the catalyst's denitrification and VOCs removal performance, and DBD plasma modification effectively enhanced the catalyst's sulfur resistance.

[0047] The DBD plasma-modified MnCeTiOx catalyst described in this embodiment underwent a 9-hour sulfur resistance synergistic test at 200℃ under complex flue gas conditions containing 50 ppm SO2 and 50 ppm toluene. The NOx removal rate consistently remained above 95%, and the toluene removal rate remained stable, indicating that the catalyst possesses excellent resistance to SO2 poisoning and synergistic removal performance under sulfur-containing atmospheres. Compared to the unmodified catalyst, DBD plasma modification effectively enhances the catalyst's sulfur resistance stability, overcoming the technical challenge of easy sulfation deactivation of traditional manganese-based catalysts under sulfur-containing atmospheres. Furthermore, this modification method is simple, easy to operate, requires no chemical reagents, and produces no secondary pollution, making it suitable for applications involving the synergistic treatment of multiple pollutants in industrial flue gas.

[0048] Example 4 Preparation of modified MnCeTiOx catalyst S1. Preparation of CeTiOx support: 0.015 mol of cerium nitrate (Ce(NO3)3·6H2O) and 0.00075 mol of tetrabutyl titanate were weighed according to a Ce:Ti molar ratio of 20:1. Both were dissolved together in 60 mL of deionized water and magnetically stirred at room temperature for 1 h until homogeneous, yielding a clear and transparent mixed solution. Subsequently, ammonia was added dropwise as an alkaline precipitant in a fume hood until the pH reached 9. Stirring continued for 3 h to form a uniform milky white suspension. The beaker was sealed with plastic wrap and allowed to stand for 18 h to allow for natural stratification and complete precipitation. The supernatant was removed, and the precipitate was centrifuged and washed successively with deionized water and ethanol until the pH was neutral. The resulting precipitate was dried in an oven at 100 °C for 18 h, and then calcined in a muffle furnace at 550 °C for 3 h to obtain the CeTiOx support.

[0049] S2, Preparation of MnCeTiOx catalyst: Weigh 0.0015 mol of manganese nitrate according to a Ce:Mn molar ratio of 10:1. Add manganese nitrate and CeTiOx to 8 ml of deionized water to form a solution. Heat and stir at 80℃ until the water is completely evaporated, then place in an oven and dry at 80℃ for 18 h. Calcine the dried sample in a muffle furnace at 550℃ for 3.5 h to obtain the MnCeTiOx catalyst.

[0050] S3, Modification Treatment: 1g of the prepared MnCeTiOx catalyst was placed in the discharge region of a dielectric barrier discharge reactor. N2 was introduced into the reactor as a carrier gas at a flow rate of 40mL / min. The plasma power supply was turned on, the discharge power was adjusted to 20W, and the treatment time was 10min to obtain the DBD plasma-modified MnCeTiOx catalyst.

[0051] The DBD plasma-modified MnCeTiOx catalyst was subjected to NOx decomposition reaction in the range of 100-350℃, under the same test conditions as in Example 1. The experimental results showed that the NOx removal rate of the modified catalyst reached over 90% in the range of 150-200℃, and approached 100% at 150℃, which was a significant improvement compared to the unmodified catalyst.

[0052] Example 5 Preparation of modified MnCeTiOx catalyst S1. Preparation of CeTiOx support: 0.025 mol of cerium nitrate hydrate (Ce(NO3)3·6H2O) and 0.00125 mol of tetrabutyl titanate were weighed according to a Ce:Ti molar ratio of 20:1. Both were dissolved together in 100 mL of deionized water and magnetically stirred at room temperature for 1 h until homogeneous, yielding a clear and transparent mixed solution. Subsequently, ammonia was added dropwise as an alkaline precipitant in a fume hood until the pH reached 9. Stirring continued for 2.5 h to form a uniform milky white suspension. The beaker was sealed with plastic wrap and allowed to stand for 18 h to allow for natural stratification and complete precipitation. The supernatant was removed, and the precipitate was centrifuged and washed successively with deionized water and ethanol until the pH was neutral. The resulting precipitate was dried in an oven at 100 °C for 18 h, and then calcined in a muffle furnace at 550 °C for 3 h to obtain the CeTiOx support.

[0053] S2, Preparation of MnCeTiOx catalyst: Weigh 0.0025 mol of manganese nitrate according to a Ce:Mn molar ratio of 10:1. Add manganese nitrate and CeTiOx to 12.5 ml of deionized water to form a solution. Heat and stir at 80 °C until the water is completely evaporated, then place in an oven and dry at 90 °C for 14 h. Calcine the dried sample in a muffle furnace at 550 °C for 3 h to obtain the MnCeTiOx catalyst.

[0054] S3, Modification Treatment: 1g of the prepared MnCeTiOx catalyst was placed in the discharge region of a dielectric barrier discharge reactor. N2 was introduced into the reactor as a carrier gas at a flow rate of 40mL / min. The plasma power supply was turned on, the discharge power was adjusted to 20W, and the treatment time was 10min to obtain the DBD plasma-modified MnCeTiOx catalyst.

[0055] The DBD plasma-modified MnCeTiOx catalyst was subjected to NOx decomposition reaction in the range of 100-350℃, under the same test conditions as in Example 1. Experimental results showed that the modified catalyst exhibited better NOx removal rates than the unmodified catalyst in the range of 100-250℃, with the NOx removal rate remaining at 100% at both 150℃ and 200℃, demonstrating excellent low-temperature denitrification activity.

[0056] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a modified MnCeTiOx catalyst, characterized in that, The preparation steps include the following: S1, add cerium salt and titanium source precursor to deionized water and stir to mix evenly; then add ammonia water dropwise to adjust the pH value, continue stirring to form a uniform suspension, let stand for natural separation, remove the supernatant, centrifuge the precipitate, wash until neutral, then dry and calcine to obtain CeTiOx catalyst. S2, the CeTiOx catalyst and manganese salt obtained in S1 are added to deionized water, heated and stirred until the water is completely evaporated, and then dried and calcined to obtain the MnCeTiOx catalyst; S3. The MnCeTiOx catalyst obtained in S2 is placed in a dielectric barrier discharge low-temperature plasma treatment device, and gas is introduced into the treatment device to carry out plasma modification treatment, thereby obtaining a DBD plasma-modified MnCeTiOx catalyst.

2. The preparation method according to claim 1, characterized in that, The cerium salt mentioned in step S1 is one or more of cerium nitrate, cerium acetate, cerium sulfate, and cerium chloride; The titanium source precursor is one or more of tetrabutyl titanate, tetraisopropyl titanate, titanium tetrachloride, and titanium oxysulfate. The molar ratio of Ce:Ti in the cerium salt and titanium source precursor is 30:1-10:1; The ratio of cerium salt to deionized water is 0.01-0.05 mol: 100 mL; The pH value is adjusted to be between 8 and 11.

3. The preparation method according to claim 1, characterized in that, The drying temperature in step S1 is 80-110℃, and the time is 12-24h; The roasting temperature is 450℃-600℃, and the time is 2-4 hours.

4. The preparation method according to claim 1, characterized in that, The manganese salt mentioned in step S2 is one or more of manganese nitrate, manganese acetate, manganese sulfate, and manganese chloride; The ratio of manganese salt to deionized water is 0.01-0.05 mol: 100 mL; The molar ratio of Ce:Mn elements in the CeTiOx catalyst to the manganese salt is 20:1-5:

1.

5. The preparation method according to claim 1, characterized in that, The drying temperature in step S2 is 80-110℃ and the time is 12-24h; the calcination temperature is 450℃-600℃ and the time is 2-4h.

6. The preparation method according to claim 1, characterized in that, The gas mentioned in step S3 is N2, or one or a mixture of several gases including O2, Ar, H2-Ar, and air; the flow rate of the gas is 20-100 mL / min. The dielectric barrier discharge low-temperature plasma treatment device is either a coaxial cylindrical dielectric barrier type or a parallel plate dielectric barrier type. The discharge power of the plasma modification treatment is 10-30W; the treatment time is 5-30min.

7. The application of a modified MnCeTiOx catalyst prepared by the method described in claims 1-6 in flue gas treatment.

8. The application according to claim 7, characterized in that, The application is in flue gas denitrification, and the catalyst operates in a temperature range of 100-250℃.

9. The application according to claim 8, characterized in that, The application is in the synergistic denitrification and VOCs removal of SO2-containing flue gas; SO2 concentration in imported flue gas ≤100ppm; The denitrification rate reaches 90%-100%; VOCs removal rate reaches 90%-100%.

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