Preparation method and application of medium resistance discharge plasma enhanced modification of smmnco denitration catalyst

Abstract

This invention discloses a dielectric barrier discharge plasma-enhanced modified SmMnCo denitrification catalyst and its preparation method, belonging to the field of air pollution control, for the efficient degradation of NO. The catalyst uses Sm as the main active component and Mn and Co as auxiliary agents, and is prepared by co-precipitation combined with radio frequency plasma activation: Mn(NO3)2·4H2O, Sm(NO3)3·6H2O, Co(NO3)2·6H2O, and Co(NO3)2·6H2O are dissolved and then co-dropped with a stabilizer solution into a Na2CO3 precipitant solution (pH=10±0.2) at a rate of 1 mL / min; the mixture is aged in a 60℃ water bath with stirring for 12 h, centrifuged and washed until neutral, dispersed in anhydrous ethanol, stirred, centrifuged, and dried to obtain the precursor; then treated in a nitrogen atmosphere radio frequency plasma (100 W, 40 min) to obtain the final product. Characterization showed that dielectric barrier discharge plasma activation successfully constructed a layered double hydroxide (LDH) precursor with reduced crystallinity and significantly increased specific surface area and acidic sites, which is suitable for the wide-temperature reaction requirements of C3H6-SCR. At the same time, it inhibited particle sintering and agglomeration, maintained the thin-plate morphology and surface uniformity, promoted the uniform exposure of active sites, and improved denitrification performance.

Description

Technical Field

[0001] This invention relates to a method for preparing and applying a dielectric barrier discharge plasma-enhanced modified SmMnCo denitration catalyst. Specifically, it is a catalyst for the effective removal of NO, an atmospheric pollutant, and belongs to the fields of air pollution control and environmental catalysis. Background Technology

[0002] Nitrogen oxides (NO) x As a significant air pollutant, it has become a major factor restricting the sustainable development of the ecological environment and endangering human health.

[0003] Selective catalytic reduction (SCR) technology is currently the mainstream engineering technology for purifying nitrogen oxides (NOx) from industrial stationary source flue gas and vehicle mobile source exhaust gas. Among them, C3H6-SCR denitrification technology, which uses propylene (C3H6) as a reducing agent, has excellent compatibility with exhaust gas from fuel-powered vehicles because the reducing agent can be directly derived from the hydrocarbon components of the exhaust gas itself, eliminating the need for an additional reducing agent dosing system. It also shows outstanding application potential in the denitrification field of non-electric industries. The catalyst is the core of C3H6-SCR denitrification technology. Its catalytic activity, temperature window, and stability directly determine the purification efficiency, operating cost, and applicable scenarios of the denitrification system. Currently, the developed C3H6-SCR catalyst systems are mainly divided into two categories: noble metal-based catalysts and transition metal oxide catalysts.

[0004] Traditional commercially available V₂O₅-WO₄(MoO₃) / TiO₂ denitration catalysts, both domestically and internationally, suffer from poor low-temperature activity (<300℃), a narrow operating temperature window (300-400℃), and vanadium species exhibiting biotoxicity and poor resistance to toxicity, thus limiting their application. To address these shortcomings of commercial catalysts, layered bimetallic hydroxides (LDHs) calcined to obtain layered bimetallic oxides (LDOs) possess significant research and development potential. These materials inherit the layered structure characteristics of the precursors, exhibiting advantages such as high specific surface area, atomically uniform dispersion of metal elements, abundant active sites, excellent thermal stability, and strong compositional tunability. By introducing the rare earth element samarium (Sm) into the LDH layers for modification, Sm's unique 4f electron structure and excellent oxygen storage / release capacity significantly enhance the catalyst's denitration performance in the C₃H₆-SCR reaction. However, the current activation process from LDH to LDO relies entirely on traditional high-temperature calcination in a muffle furnace. This process suffers from insurmountable technical drawbacks: during high-temperature calcination, the LDH precursor is prone to excessive collapse of its layered structure and agglomeration and growth of metal oxide grains, leading to a significant decrease in the catalyst's specific surface area; furthermore, the long calcination cycle is unfavorable for large-scale preparation. Dielectric barrier discharge (DBD) plasma technology, as a novel and green material activation and modification technology, can generate a large number of high-energy electrons and active free radicals under ambient temperature and pressure conditions through alternating electric fields. This enables the dehydroxylation and deintercalation of the LDH precursor, achieving efficient activation of LDO. It offers advantages such as ambient pressure operation, short processing cycle, and low energy consumption, making it an ideal technology for preparing high-performance LDO denitration catalysts. Currently, the preparation of plasma-modified samarium-based wide-temperature-range layered catalysts and their application in the C3H6-SCR reaction have not yet been developed. Therefore, developing a SmMnCo denitration catalyst preparation process based on dielectric barrier discharge plasma has significant research value and promising prospects for industrial application.

[0005] Yan et al. (Q. Yan, J. Xiao, R. Gui, et al., Insights into enhancement of NH3-SCR activity and N2selectivity of LDHs-derived NiMnAlO x Catalysts: Combination of experiments and DFT calculations, ACB-Env, 343 (2024) 123489.) LDH-derived NiMnAlO4 prepared x The catalyst achieved over 95% NO removal within a temperature range of 100-250 °C.x Conversion rate. Xu et al. (J. Xu, T. Tang, X. Sheng, et al., Excellent activity caused by dielectric barrier discharge (DBD) plasma activation for selective catalytic reduction with propylene (C3H6-SCR): Insight into the low temperature catalytic behavior of Mn / ZSM-5 catalysts, J. Environ. Chem. Eng, 10 (2022)107009.) prepared a series of low-load Mn / ZSM-5 catalysts by DBD plasma activation co-precipitation method, achieving high conversion rates in the range of 120-270 °C. o C, an NO conversion rate exceeding 96% was observed. This indicates that plasma activation can generate higher diffusion of the active substance Mn, larger pore size, and more abundant oxygen vacancies, while exhibiting lower zeolite destructiveness. In summary, the high dispersibility and structural tunability of the LDH derivative layered structure, as well as the enhancement of its denitrification performance by dielectric barrier discharge plasma activation modification of the catalyst, have all been verified by this study. The combination of these two approaches provides a feasible approach for developing Sm-based layered catalysts with excellent C3H6-SCR activity.

[0006] The design concept of this patent is to optimize the catalyst activation and modification method to prepare a highly active, wide-temperature-range Sm-based denitration catalyst. Based on the literature, previous attempts to activate the SmMnCo catalyst precursor using a traditional muffle furnace high-temperature calcination process revealed significant limitations: calcination at 400℃ caused the layered structure of the LDH precursor to collapse and metal particles to agglomerate, ultimately resulting in insufficient low-temperature denitration activity of the catalyst. Furthermore, the calcination process is energy-intensive and time-consuming. Therefore, this patent uses dielectric barrier discharge (DBD) plasma technology to replace the traditional high-temperature calcination process. However, conventional plasma modification methods reported in the literature cannot be directly adapted to the SmMnCo ternary system because even small changes in the discharge atmosphere, discharge power, and discharge time can significantly affect the crystal structure and active species of the catalyst. Directly using conventional DBD plasma parameters leads to problems such as insufficient catalyst activation and crystal structure destruction, becoming a key technical challenge in the preparation of this catalyst. To this end, this design conducted a series of process optimizations on the DBD plasma modification process. Through extensive experiments, core process parameters such as discharge atmosphere, discharge power, and discharge time were screened and controlled, with each parameter selection having a clear purpose. A suitable discharge atmosphere was selected to control the type and concentration of active species in the plasma field; appropriate discharge power was controlled to balance the etching effect of high-energy particles on the catalyst and the integrity of the crystal structure, avoiding insufficient activation of the precursor due to too low power and destruction of the LDH layered structure due to too high power; and a reasonable discharge time was controlled to achieve sufficient activation and surface modification of the catalyst precursor, avoiding insufficient activation due to too short a time and particle agglomeration due to too long a time. Finally, the optimized dielectric barrier discharge plasma process allows the catalyst activation process to be carried out at room temperature and pressure, resulting in a simple process, short processing cycle, and low energy consumption. Combined with the synergistic effect of Sm, Mn, and Co, the catalytic performance is significantly improved. The innovation of this design lies in applying dielectric barrier discharge plasma technology to the activation and modification of SmMnCo layered denitration catalysts, completely replacing the traditional high-temperature calcination process. Through multi-parameter synergistic control of discharge atmosphere, power, and time, the layered structure and surface physicochemical properties of the catalyst are precisely optimized, highlighting the design's innovation and practicality. The optimally modified SmMnCo catalyst exhibits high denitration activity, a wide operating temperature window, and significantly lower energy consumption than traditional calcination processes, making it more suitable for the demands of continuous industrial production. Summary of the Invention

[0007] The purpose of this invention is to provide a method for preparing and applying a dielectric barrier discharge plasma-enhanced modified SmMnCo denitration catalyst. This method has the advantages of simple process, short processing cycle, and low energy consumption. The SmMnCo catalyst prepared by this method significantly improves the low-temperature denitration activity of the catalyst and broadens its operating temperature window.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for preparing a dielectric barrier discharge plasma-enhanced modified SmMnCo denitration catalyst includes the following steps: (a) Weigh out the active component Sm(NO3)3·6H2O, the auxiliary agent Mn(NO3)2·4H2O and the auxiliary agent Co(NO3)2·6H2O in the stoichiometric ratio and dissolve them in deionized water. Stir until completely dissolved to obtain a transparent solution A. (b) Dissolve a measured amount of Na2CO3 in deionized water to obtain precipitant B, and then dissolve an appropriate amount of Na2CO3 in deionized water to obtain stabilizer C. (c) While stirring, add solution A from step (a) dropwise to solution B from step (b), and adjust the pH to approximately 10 with solution C; (d) Incubate the solution obtained in step (c) at 60°C. o Aged under C water bath with stirring for 12 hours; (e) Transfer the solution obtained in step (d) into a centrifuge tube and centrifuge, then wash with anhydrous ethanol until neutral; (f) Place the sample catalyst obtained in step (e) in an oven at 110°C and dry overnight; (g) Grind the sample obtained in step (f) into a fine powder, place it in a dielectric barrier discharge plasma surface treatment instrument, and discharge for 40 minutes under a nitrogen atmosphere with a power of 100W to obtain the SmMnCo catalyst.

[0009] According to the above scheme, the molar ratio of active component Sm to auxiliary agent Mn is n(Sm(NO3)3·6H2O): n(Mn(NO3)2·4H2O)=1:0.42.

[0010] According to the above scheme, the molar ratio of active component Sm to auxiliary agent Co is n(Sm(NO3)3·6H2O): n(Co(NO3)2·6H2O)=1:0.05.

[0011] According to the above scheme, the molar ratio of active component Sm to precipitant is n(Sm(NO3)3·6H2O): n(Na2CO3)=1:7.

[0012] Preferably, the drying temperature is 110°C and the drying time is 12 hours; The discharge atmosphere is nitrogen. The discharge power is 100W; The discharge time is 40 minutes.

[0013] The present invention also provides the application of the C3H6-SCR catalyst prepared by any of the above-described technical solutions in tail gas denitrification.

[0014] Compared with the prior art, the present invention has the following advantages: 1. The SmMnCo catalyst for SCR denitrification provided by this invention exhibits superior low-temperature catalytic activity and a wide operating temperature window, achieving a maximum NO conversion rate of 98% at 350℃. 80 The operating temperature window has been widened to 100-450℃.

[0015] 2. This preparation method is simple, has a short processing cycle, low energy consumption, and is suitable for industrial production. Attached Figure Description

[0016] Figure 1 The graphs show the catalytic activity test results of the catalysts prepared in Examples 1, 2, 3 and 11.

[0017] Figure 2 The graphs show the catalytic activity test results of the catalysts prepared in Examples 4, 5, 6, 7 and 11.

[0018] Figure 3 The graphs show the catalytic activity test results of the catalysts prepared in Examples 8, 9, 10 and 11.

[0019] Figure 4 The XRD pattern of the catalyst prepared in Example 4 is shown.

[0020] Figure 5 The NH3-TPD spectrum of the catalyst prepared in Example 4.

[0021] Figure 6 SEM spectra of the catalyst prepared in Example 4: (a)(c) SmMnCo-C, (b)(d) SmMnCo-DBD, (e)(f)(g)(h) EDS-Mapping of SmMnCo-DBD. Detailed Implementation

[0022] The present invention will be further illustrated by some implementation examples below, but these examples do not limit the scope of the invention.

[0023] Example 1 Synthesis of SmMnCo-DBD-N2 catalyst Weigh appropriate amounts of Mn(NO3)2·4H2O, Sm(NO3)3·6H2O, and Co(NO3)2·6H2O, add an appropriate amount of deionized water, and stir until completely dissolved. Weigh out a predetermined concentration of Na2CO3 and dissolve it in distilled water to prepare a precipitant solution. Then, add an appropriate amount of Na2CO3 to deionized water to obtain a stabilizer. Under constant temperature and magnetic stirring, gradually add the metal salt solution and stabilizer solution dropwise (at a dropping rate of 1 mL / min) to the prepared Na2CO3 precipitant solution until the pH stabilizes to 10 ± 0.2. The mixed solution is then aged in a 60℃ water bath for 12 h. After aging, centrifuge and wash several times until the pH of the supernatant is neutral. Dissolve the washed precipitate in an appropriate amount of anhydrous ethanol, stir continuously for 2 h, centrifuge, and then dry in an oven overnight to obtain the precursor. After drying, the powder sample is placed in a dielectric barrier discharge plasma surface treatment instrument, and the catalyst is obtained by discharging for 10 minutes under a nitrogen atmosphere at a power of 100W.

[0024] Catalyst evaluation The catalyst activity was evaluated in a self-made continuous flow fixed-bed reactor. The reaction tube was a quartz tube with an inner diameter of 6 mm and a length of 33 cm. The reaction temperature was measured by a thermocouple placed in the middle of the reaction tube and controlled by a programmed temperature controller. The gas flow rate was controlled by a mass flow meter. The reactant gases were 400 ppm C3H6, 400 ppm NO, 3% O2, and equilibrium gas Ar. In the experiment, the catalyst dosage was 0.2 g, the reaction temperature was 100℃~450℃, and samples were taken every 50℃. The NO conversion rate was calculated using a flue gas analyzer (MRU, VARIO PLUS). The NO conversion curves of the catalyst at different temperature points are shown in the figure below. Figure 1 As shown.

[0025] Examples 2-3 Compared with Example 1, only the discharge atmosphere during the preparation process was different; all other processes were the same as in Example 1, and the finished catalysts were obtained. The catalyst preparation conditions for Examples 2 and 3 are shown in Table 1.

[0026] Catalyst evaluation Following the evaluation method of Implementation Case 1, the conversion curves of the catalyst for NO at different temperature points are shown below. Figure 1 As shown. Its 100℃, 150℃, highest NO conversion rate, and T... 80 The operating window temperature is shown in Table 2.

[0027] Example 4 Synthesis of SmMnCo-DBD-40min catalyst The discharge time differs from Example 1, specifically as follows: Appropriate amounts of Mn(NO3)2·4H2O, Sm(NO3)3·6H2O, and Co(NO3)2·6H2O were weighed and added to an appropriate amount of deionized water, stirring until completely dissolved. A predetermined concentration of Na2CO3 was weighed and dissolved in distilled water to prepare a precipitant solution. Then, an appropriate concentration of Na2CO3 was added to deionized water to obtain a stabilizer. The mixture was magnetically stirred at a constant temperature. During this process, the metal salt solution and stabilizer solution were gradually added dropwise (at a dropping rate of 1 mL / min) to the pre-prepared Na2CO3 precipitant solution until the pH stabilized to 10 ± 0.2. The mixed solution was then aged in a 20°C water bath for 12 hours. After aging, it was centrifuged and washed several times until the pH of the supernatant was neutral. The washed precipitate was dissolved in an appropriate amount of anhydrous ethanol, stirred continuously for 2 hours, centrifuged, and then dried in an oven overnight to obtain the precursor. After drying, the powder sample is placed in a dielectric barrier discharge plasma surface treatment instrument, and the catalyst is obtained by discharging for 40 minutes under a nitrogen atmosphere at a power of 100W.

[0028] Catalyst evaluation Following the evaluation method of Implementation Case 1, the conversion curves of the catalyst for NO at different temperature points are shown below. Figure 2 As shown. Its 100℃, 150℃, highest NO conversion rate, and T... 80 The operating window temperature is shown in Table 2.

[0029] Examples 5-7 Compared with Example 4, only the discharge time during catalyst preparation was different; all other processes were the same as in Example 4, and the finished catalysts were obtained. The catalyst preparation conditions for Examples 5 to 7 are shown in Table 1.

[0030] Catalyst evaluation Following the evaluation method of Implementation Case 1, the conversion curves of the catalyst for NO at different temperature points are shown below. Figure 2 As shown. Its 100℃, 150℃, highest NO conversion rate, and T... 80 The operating window temperature is shown in Table 2.

[0031] Example 8 Synthesis of SmMnCo-RF-150W catalyst Unlike Example 4, the discharge power was adjusted to 150W, as follows: Appropriate amounts of Mn(NO3)2·4H2O, Sm(NO3)3·6H2O, and Co(NO3)2·6H2O were weighed and added to an appropriate amount of deionized water, stirring until completely dissolved. A predetermined concentration of Na2CO3 was weighed and dissolved in distilled water to prepare a precipitant solution. Then, an appropriate concentration of Na2CO3 was added to deionized water to obtain a stabilizer. The mixture was magnetically stirred at a constant temperature. During this process, the metal salt solution and stabilizer solution were gradually added dropwise (at a dropping rate of 1 mL / min) to the pre-prepared Na2CO3 precipitant solution until the pH stabilized to 10 ± 0.2. The mixed solution was then aged in a 60°C water bath for 10 hours. After aging, it was centrifuged and washed several times until the pH of the supernatant was neutral. The washed precipitate was dissolved in an appropriate amount of anhydrous ethanol, stirred continuously for 2 hours, centrifuged, and then dried in an oven overnight to obtain the precursor. After drying, the powder sample is placed in a dielectric barrier discharge plasma surface treatment instrument, and the catalyst is obtained by discharging for 40 minutes under a nitrogen atmosphere at a power of 150W.

[0032] Catalyst evaluation Following the evaluation method of Implementation Case 1, the conversion curves of the catalyst for NO at different temperature points are shown below. Figure 3 As shown. Its 100℃, 150℃, highest NO conversion rate, and T... 80 The operating window temperature is shown in Table 2.

[0033] Examples 9-10 Compared with Example 8, only the discharge time in the catalyst preparation was different; the other processes were the same as in Example 8, and the finished catalysts were obtained. The catalyst preparation conditions for Examples 9 to 10 are shown in Table 1.

[0034] Catalyst evaluation Following the evaluation method of Implementation Case 1, the conversion curves of the catalyst for NO at different temperature points are shown below. Figure 3 As shown. Its 100℃, 150℃, highest NO conversion rate, and T... 80 The operating window temperature is shown in Table 2.

[0035] Example 11 Synthesis of SmMnCo-C catalyst Unlike Examples 1-10, the activation method was conventional calcination, specifically as follows: Appropriate amounts of Mn(NO3)2·4H2O, Sm(NO3)3·6H2O, and Co(NO3)2·6H2O were weighed and added to an appropriate amount of deionized water, stirring until completely dissolved. A predetermined concentration of Na2CO3 was weighed and dissolved in distilled water to prepare a precipitant solution. Then, an appropriate concentration of Na2CO3 was added to deionized water to obtain a stabilizer. The mixture was magnetically stirred at a constant temperature. During this process, the metal salt solution and stabilizer solution were gradually added dropwise (at a dropping rate of 1 mL / min) to the pre-prepared Na2CO3 precipitant solution until the pH stabilized to 10 ± 0.2. The mixed solution was then aged in a 60°C water bath for 12 hours. After aging, it was centrifuged and washed several times until the pH of the supernatant was neutral. The washed precipitate was dissolved in an appropriate amount of anhydrous ethanol, stirred continuously for 2 hours, centrifuged, and then dried in an oven overnight to obtain the precursor. After drying, the powder sample was calcined in a muffle furnace and pressed into tablets to obtain the catalyst.

[0036] Catalyst evaluation Following the evaluation method of Implementation Case 1, the conversion curves of the catalyst for NO at different temperature points are shown below. Figure 1-3 As shown. Its 100℃, 150℃, highest NO conversion rate, and T... 80 The operating window temperature is shown in Table 2.

[0037] Table of radio frequency plasma activation preparation conditions for examples: Specific embodiments of radio frequency plasma activation preparation are shown in Table 1: Activity evaluation results: The specific activity evaluation results are shown in Table 2: Serial Number Catalyst name NO conversion rate (%) at 100℃ NO conversion rate (%) at 150℃ Highest NO conversion rate (%) <![CDATA[Operating temperature window T 80 (°C)]]> 1 <![CDATA[SmMnCo-DBD-N2]]> 76 77 97 210-450 2 SmMnCo-DBD-AIR 65 67 95 210-440 3 SmMnCo-DBD-AR 70 75 84 210-450 4 SmMnCo-DBD-40min 83 88 98 100-450 5 SmMnCo-DBD-20min 74 87 98 125-450 6 SmMnCo-DBD-10min 76 77 96 210-450 7 SmMnCo-DBD-5min 73 75 96 180-450 8 SmMnCo-DBD-150W 82 85 98 100-425 9 SmMnCo-DBD-100W 83 88 98 100-450 10 SmMnCo-DBD-50W 64 65 93 325-450 11 SmMnCo-C 64 80 98 150-450 XRD characterization Figure 4The catalysts of Example 4 (abbreviated as SMC-DBD dielectric barrier discharge plasma activation) and Example 10 (abbreviated as SMC-C conventional calcination) are shown. SMC-Precursor XRD analysis of the precursors of both catalysts revealed typical LDH (PDF#37-0630) diffraction peaks at 2θ≈11.82°, 23.26°, and 35.96°, corresponding to the (003), (006), and (012) crystal planes, respectively. This indicates the formation of a carbonate-intercalated LDH structure, and the absence of independent diffraction peaks for Mn and Co related phases. In the XRD pattern of SMC-C, the characteristic peaks of LDH (003), (006), and (012) completely disappeared, replaced by characteristic peaks of Sm2O2CO3. This indicates that conventional high-temperature calcination caused irreversible collapse of the LDH layered structure, sintering of the layered metals, and phase transformation to Sm2O2CO3. In the catalyst spectrum activated by DBD, the characteristic peaks of LDH were clearly preserved, which is an advantage of plasma "low-temperature non-thermal activation": it avoids the destruction of the layered structure by high temperature and completely preserves the layered derivatized structure of LDH. It can be seen that the lower peak intensity and wider peak width of SMC-DBD indicate that the carbonate ions in the interlayer region are etched by plasma. The increased half-width at half-maximum (WHM) represents a decrease in crystallinity, and a decrease in crystallinity usually increases the specific surface area and the number of active sites of the catalyst, which has a positive effect on improving the activity of C3H6-SCR reaction. This further explains why the DBD sample has better denitrification stability in the high-temperature region.

[0038] TPD characterization Figure 5 The NH3-TPD test results of the catalysts in Example 4 (abbreviated as SMC-DBD dielectric barrier discharge plasma activation) and Example 10 (abbreviated as SMC-C conventional calcination) are presented to reflect the acid strength of the catalysts, and the desorption peak area reflects the acidity. The desorption peaks in different temperature ranges correspond to different acidic site characteristics: the low-temperature region of 100-150 ℃ corresponds to weakly acidic sites, the broad and gentle peaks in the medium-temperature region of 150-400 ℃ correspond to moderately strong acidic sites, while the desorption peaks in the high-temperature region of 400-750 ℃ ​​reflect strongly acidic sites. As shown in the figure, SMC-C is dominated by a strongly acidic peak at 597 ℃, indicating excessively high acidity; and there are very few acidic sites in the low-temperature and medium-temperature regions. In contrast, the desorption peaks of the plasma-treated SMC-DBD catalyst all shift towards the low-temperature weakly acidic direction, and the peak area increases significantly. The weakly to moderately acidic sites ensure effective adsorption of reactants while enabling rapid desorption in the high-temperature region, avoiding excessive adsorption and side reactions. The SMC-DBD catalyst has an acidic site distribution covering the low-temperature, medium-temperature, and high-temperature range, exhibiting synergistic effects of weak, medium-strong, and strong acids. Its abundant acidic sites are suitable for reactions across a wide temperature range, which aligns with its excellent wide-temperature-range activity.

[0039] SEM characterization The catalysts of Example 4 (SMC-DBD dielectric barrier discharge plasma activation) and Example 10 (SMC-C conventional calcination) were characterized using SEM with mapping, and the results are shown in Figure 6. Figures 6(a) and (c) are magnified images of the SMC-C catalyst at 2 μm and 500 nm, respectively. The SMC-C catalyst exhibits a sheet-like morphology, but with obvious fractures, wrinkles, and irregular edges. Upon magnification, the sheet surface shows a distinct porous structure, but also has clustered nanoparticles attached. This is consistent with XRD analysis. Figures 6(b) and (d) are magnified images of the SMC-DBD catalyst at 2 μm and 500 nm, respectively. The SMC-DBD catalyst shows significantly improved sheet-like structure regularity, smooth edges, and no obvious fractures, indicating that low-temperature plasma activation avoids thermal stress and better preserves the integrity of the precursor's sheet-like morphology. Upon magnification, almost no agglomerated particles are visible, with only a few fine protrusions remaining. Low-temperature plasma activation effectively suppressed particle sintering and agglomeration, maintained surface uniformity, and facilitated the uniform exposure of active sites. This is consistent with XRD analysis showing that the plasma-activated catalyst retains the layered LDH structure, which is an important reason for the excellent activity of the SMC-DBD catalyst. Figure 6 (eh) shows the EDS-Mapping results of the SMC-DBD catalyst, indicating that O, Sm, Mn, and Co elements are uniformly distributed in the co-precipitated catalyst, and each element is highly dispersed on the catalyst surface. Studies have shown that higher catalyst dispersion and larger specific surface area are more conducive to improving catalyst activity. It can be seen that traditional calcination leads to severe sintering and agglomeration of the catalyst. In contrast, plasma-activated catalysts exhibit a more uniform distribution. This is because the newly formed nanoparticles in the plasma are mainly negatively charged, which effectively inhibits particle agglomeration. Therefore, the plasma-activated catalyst exhibits the highest dispersion and excellent activity in the C3H6-SCR process.

Claims

1. A method for preparing and applying a dielectric barrier discharge plasma-enhanced modified SmMnCo denitration catalyst, the preparation method comprising the following steps: (a) Weigh out the stoichiometric proportions of active component Sm(NO3)3·6H2O, auxiliary agent Mn(NO3)2·4H2O, and auxiliary agent Co(NO3)2·6H2O, dissolve them in deionized water, and stir until completely dissolved to obtain a transparent solution A; (b) Dissolve a measured amount of Na2CO3 in deionized water to obtain precipitant B, and then dissolve an appropriate amount of Na2CO3 in deionized water to obtain stabilizer C. (c) While stirring, add solution A from step (a) dropwise to solution B from step (b), and adjust the pH to approximately 10 with solution C; (d) The solution obtained in step (c) is aged by stirring in a water bath; (e) Transfer the solution obtained in step (d) into a centrifuge tube and centrifuge, then wash with anhydrous ethanol until neutral; (f) Place the sample catalyst obtained in step (e) in an oven at 110°C and dry overnight; (g) Grind the sample obtained in step (f) into a fine powder, place it in a dielectric barrier discharge plasma surface treatment instrument, and discharge for 40 minutes under a nitrogen atmosphere with a power of 100W to obtain the SmMnCo catalyst.

2. The preparation method of the dielectric barrier discharge plasma-enhanced modified SmMnCo denitration catalyst according to claim 1, characterized in that, The molar ratio of active component Sm to auxiliary agent Mn is n(Sm(NO3)3·6H2O): n(Mn(NO3)2·4H2O)=1:0.

42.

3. The method for preparing the dielectric barrier discharge plasma-enhanced modified SmMnCo denitration catalyst according to any one of claims 1-2, characterized in that, The molar ratio of the active component Sm to the auxiliary agent Co is n(Sm(NO3)3·6H2O): n(Co(NO3)2·6H2O)=1:0.

05.

4. The method for preparing the dielectric barrier discharge plasma-enhanced modified SmMnCo denitration catalyst according to any one of claims 1-3, characterized in that, The molar ratio of the active component Sm to the precipitant is n(Sm(NO3)3·6H2O): n(Na2CO3)=1:

7.

5. The method for preparing the dielectric barrier discharge plasma-enhanced modified SmMnCo denitration catalyst according to any one of claims 1-4, characterized in that, The discharge atmosphere was nitrogen, the discharge power was 100W, and the discharge time was 40min.

6. The application of the C3H6-SCR NO degradation catalyst according to any one of claims 1-5 in tail gas denitrification.

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