A method for modifying a cerium-based catalyst with enhanced chlorine resistance by plasma

Abstract

The present invention discloses a method for modifying a cerium-based catalyst with enhanced chlorine resistance by plasma; the modification method is as follows: First, place the cerium-based catalyst to be treated into a plasma discharge device. Second, start the plasma discharge device, and perform plasma discharge under the atmosphere of a mixed gas of Ar and H2, so as to enhance the chlorine resistance of the cerium-based catalyst. During the operation of the plasma discharge device, the volume ratio of Ar to H2 in the gas atmosphere is (1-5):(6-10), the gas flow rate is 100 mL / min to 200 mL / min, and the discharge time is 10 min to 30 min. In the present invention, the modification of the cerium-based catalyst by microwave plasma improves its active sites and acidic sites, and can prevent the phenomenon of chlorine poisoning inactivation during the degradation of CVOCs, thereby significantly improving the continuous use stability of the cerium-based catalyst in CVOCs.

Description

Technical Field

[0001] The present invention belongs to the technical field of CVOCs treatment, and particularly relates to a method for modifying a cerium-based catalyst with enhanced chlorine resistance by plasma. Background Art

[0002] The emission control of VOCs (Volatile organic compounds) has always been a hot topic. Volatile organic pollutants can damage the ozone layer, cause smog pollution and affect human health. CVOCs (Chlorinated volatile organic compounds) are the most notable type of pollutants among volatile organic pollutants. CVOCs are highly toxic and harmful volatile organic compounds, including chlorinated alkanes, chlorinated olefins, chlorinated aromatic hydrocarbons and their derivatives, as well as high molecular weight organic compounds such as PCBs, and are usually emitted during industrial production and combustion processes. These organic compounds are difficult to degrade naturally and can exist in the environment for a long time. Among them, chlorinated alkanes and chlorinated olefins are usually used as solvents, degreasing agents or raw materials for other chemical components. Chlorinated aromatic hydrocarbons and their derivatives are often used as intermediates, that is, as precursors of certain compounds during the synthesis process. Other sources include the escape during the disinfection of urban tap water, the continuous volatilization of products containing CVOCs, and the incomplete combustion of garbage. Chlorinated alkanes and chlorinated olefins are usually intermediates and solvents for organic synthesis in industry. During the production process, pollution is generated by volatilization or leakage into the atmosphere. After treatment, some CVOCs still remain in water, soil and air, posing potential health risks to humans through inhalation and skin contact. Therefore, strict supervision and control of such pollutants are needed to protect human health and environmental safety. Currently, the main treatment technologies for CVOCs are adsorption, direct combustion and catalytic combustion.

[0003] The adsorption method mainly adsorbs CVOCs through the action of adsorbents to achieve the removal effect, which is mainly divided into physical adsorption and chemical adsorption. The adsorption method is not suitable for adsorption under the conditions of small flow rate, high temperature and high humidity, has high requirements for adsorbents, and the treatment of adsorbents after adsorption is a problem. The direct combustion method decomposes CVOCs into harmless substances such as CO2 and H2O under high temperature and oxygen conditions through devices such as incinerators, and toxic substances such as HCl and Cl2 will also be produced. This method needs to be carried out at high temperature, has high requirements for equipment, and may produce toxic substances such as dioxins under the condition of incomplete combustion. The catalytic combustion method can have a good degradation effect on CVOCs under low temperature conditions under the action of a catalyst. Compared with the traditional combustion for degrading pollutants, catalytic combustion can efficiently degrade organic pollutants with different concentrations, and the energy consumption is relatively low in this process, so it has been widely used in engineering. The current catalysts in catalytic combustion are divided into noble metal catalysts, transition metal catalysts and molecular sieve catalysts. This method has many advantages in treating organic waste gas, but when treating chlorine-containing pollutants, chloride ions are prone to combine with the metals in the catalyst, resulting in catalyst deactivation. Therefore, it is necessary to develop chlorine-resistant catalysts. Modifying catalytic materials with cold plasma is a relatively hot topic at present.

[0004] Cold plasma is a new method with low reaction temperature, rapid reaction and high energy of active substances produced at present, and is widely used in the modification of catalysts. The action of plasma can reduce and reorganize the active components on the surface of catalytic materials. By adjusting the plasma treatment parameters, catalytic materials with more stable surface active components and structures can be obtained. In addition, plasma treatment can also change the surface properties and electronic structures of catalytic materials to expose more active sites. For catalytic materials deactivated by carbon deposition, plasma treatment modification can remove carbon deposition or materials modified by plasma can prevent the occurrence of carbon deposition. For catalytic materials deactivated by poisoning, plasma modification can make them contain more active sites and more stable structures to improve the anti-poisoning properties of catalytic materials.

[0005] In previous engineering practices, the performance of plasma-modified catalysts would change due to different gas atmospheres and the discharge sequences of different gases. For different actual treatment requirements, the performance of the catalyst can be optimized by changing the discharge gas or the discharge sequence of the gas to improve its catalytic activity and anti-poisoning ability, and its process parameters can be determined by historical experience or through conditional experiments. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for modifying cerium-based catalysts with enhanced plasma anti-chlorine performance.

[0007] A method for modifying a cerium-based catalyst with enhanced chlorine resistance by plasma enhancement provided by the present invention comprises the following steps:

[0008] Step 1: Place the cerium-based catalyst to be processed into a plasma discharge device.

[0009] Step 2: Start the plasma discharge device, and perform plasma discharge under the atmosphere of a mixed gas of Ar and H2, so as to enhance the chlorine resistance of the cerium-based catalyst. During the operation of the plasma discharge device, the volume ratio of Ar to H2 in the gas atmosphere is (1-5):(6-10), the gas flow rate is 100 mL / min - 200 mL / min, and the discharge time is 10 min - 30 min.

[0010] Preferably, the cerium-based catalyst is specifically a V / CeO2 composite material; the V / CeO2 composite material is obtained by loading V on a CeO2 support through an impregnation method. The mass fraction of V in the V / CeO2 catalyst is 0.1 wt% - 0.6 wt%.

[0011] Preferably, the CeO2 support adopts CeO2 porous nanorods;

[0012] Preferably, during the operation of the plasma discharge device, the discharge power is 100 W - 600 W.

[0013] Preferably, the gas atmosphere of the mixing ratio of Ar and H2, the gas flow rate, the plasma discharge time, and the discharge power are used as the four key parameters of the plasma discharge device; preferably, the b-group basic catalyst modification scheme is formulated through a multi-layer feedforward neural network:

[0014] (1) Formulate the b-group basic catalyst modification scheme, where 1 ≤ b ≤ 10. Each group of basic catalyst modification schemes includes corresponding four key parameters.

[0015] (2) Respectively perform plasma modification on the cerium-based catalyst according to the b-group basic catalyst modification scheme to obtain the modified catalysts corresponding to the b-group basic catalyst modification scheme. Test the b-group modified catalysts to obtain the catalytic degradation efficiency and catalyst stability corresponding to the b-group basic catalyst modification scheme. Construct a basic experimental data set composed of the key parameters, catalytic degradation efficiency, and catalyst stability corresponding to the b-group basic catalyst modification scheme.

[0016] (3) Use the mixing ratio of Ar and H2 in the gas atmosphere, the gas flow rate, the plasma discharge time, and the discharge power as input parameters, and the catalytic degradation rate of CVOCs and the catalyst stability as output parameters to construct a parameter optimization model; the parameter optimization model adopts a BP neural network. Train the parameter optimization model using the basic experimental data set.

[0017] (4) Use the parameter optimization model to simulate the catalytic degradation efficiency and catalyst stability corresponding to different combinations of key parameters, and screen out the combination of key parameters that meet the requirements of the preset catalytic degradation efficiency and catalyst stability.

[0018] Preferably, after step (3), the root mean square error and coefficient of determination are used to evaluate the performance of the trained parameter optimization model. When the prediction performance of the parameter optimization model fails to reach the desired accuracy, the genetic algorithm is used to optimize the initial weights and thresholds of the parameter optimization model, and the maximum number of iterations is adjusted; then, the parameter optimization model is retrained again until the prediction performance of the parameter optimization model reaches the desired accuracy.

[0019] Preferably, in step (3), the parameter optimization model is trained by the error backpropagation algorithm.

[0020] Preferably, the parameter optimization model adopts a three-layer BP neural network with a topological structure of 4-9-1, and the number of neurons in the hidden layer is 9.

[0021] Preferably, the plasma discharge device adopts a microwave plasma modification device. The microwave plasma modification device includes a microwave source, a microwave transmission system, a microwave reaction system, a vacuum system, and a gas distribution system. The microwave output port of the microwave source is connected to the microwave input port of the microwave transmission system. The microwave output port of the microwave transmission system is connected to the input port of the microwave reaction system. The gas output port of the gas distribution system is connected to the gas input port of the microwave reaction system. The gas distribution system is used to provide a mixed gas of hydrogen and argon to the reaction chamber of the microwave reaction system; the air extraction port of the vacuum system is connected to the vacuum interface of the microwave reaction system.

[0022] Preferably, a coupling cavity is provided at the input port of the microwave reaction system; the coupling cavity is used to convert the microwave from the TE operating mode to the TM operating mode.

[0023] Preferably, a cooling water channel is surrounded around the reaction chamber in the microwave reaction system. The cooling water channel is connected to an external cooling water system.

[0024] The beneficial effects of the present invention are:

[0025] In the present invention, the modification of the cerium-based catalyst by microwave plasma improves its active sites and acidic sites, and is not prone to chlorine poisoning inactivation during the degradation of CVOCs, thereby significantly improving the continuous use stability of the cerium-based catalyst in CVOCs.

[0026] The present invention combines experiments with neural network optimization. Only a small number of experiments are required to simultaneously optimize four key parameters, namely, the mixing ratio of Ar and H2 in the gas atmosphere, the gas flow rate, the plasma discharge time, and the discharge power, thereby significantly improving the catalytic activity and stability of the modified cerium-based catalyst. Description of the Drawings

[0027] Figure 1 It is a schematic diagram of the microwave plasma modification device adopted by the present invention.

[0028] Figure 2 It is a schematic diagram of the hierarchical structure of the parameter optimization model constructed by the present invention.

[0029] Figure 3 It is a schematic diagram of the training process of the parameter optimization model constructed by the present invention.

[0030] Figure 4 It is a schematic diagram of the catalyst activity evaluation device used in the present invention.

[0031] Figure 5 It is a comparison chart of the treatment efficiency of CVOCs waste gas by the cerium-based catalyst before and after modification in the present invention over time. Detailed Embodiments

[0032] The present invention will be further described below with reference to the accompanying drawings.

[0033] As Figure 1 shown, a method for modifying a cerium-based catalyst with plasma-enhanced chlorine resistance, the microwave plasma modification device adopted by it includes a microwave source 1, a microwave transmission system 2, a microwave reaction system 3, a vacuum system 4, a gas distribution system 5, and a cooling water system 6. The microwave output port of the microwave source 1 is connected to the microwave input port of the microwave transmission system 2. The microwave source (HMG-2060K) is a high-voltage DC power supply with a power frequency of 50 Hz, high precision, and low ripple. The microwave generated by the microwave source 1 is transmitted by the microwave transmission system 2, which can ensure that the reflected wave is not affected by the magnetron and is convenient to adjust to make the microwave power reach the optimal output.

[0034] The microwave output port of the microwave transmission system 2 is connected to the input port of the microwave reaction system 3. The input port of the microwave reaction system 3 is provided with a coupling cavity; the coupling cavity converts the TE working mode of the rectangular waveguide of the microwave into the TM working mode in the cavity, expanding the operating range of the equipment. A cooling water channel is surrounded around the reaction cavity in the microwave reaction system 3, and the quartz glass, the sealing ring and the cavity wall are cooled in time through the cooling water system to prevent the plasma from corroding the cavity. The cooling water output port of the cooling water system 6 is connected to the water-cooled flow-through port of the microwave reaction system 3. The gas output port of the gas distribution system 5 is connected to the gas input port of the microwave reaction system 3. The gas distribution system 5 can supply a mixed gas of hydrogen and argon to the reaction cavity of the microwave reaction system 3; the air extraction port of the vacuum system 4 is connected to the vacuum interface of the microwave reaction system 3.

[0035] In some embodiments, the ultimate vacuum degree of the reaction cavity in the microwave reaction system 3 is 8×10-6 Torr.

[0036] In some embodiments, the microwave reaction system 3 can inject multiple gases simultaneously, and the flow rate of each gas is detected by an independent mass flowmeter.

[0037] The process of modifying the cerium-based catalyst by using the above microwave plasma modification device is as follows:

[0038] Step 1: Design and formulate b groups of basic catalyst modification schemes through a multi-layer feedforward neural network (MLPNN), where 1 ≤ b ≤ 10. Each basic catalyst modification scheme includes four key parameters for catalyst modification, namely the mixing ratio of Ar and H2 in the gas atmosphere, the gas flow rate, the plasma discharge time, and the discharge power. The value ranges of the four key parameters of the basic catalyst modification scheme are as follows: the volume ratio of Ar to H2 in the gas atmosphere is (1-5):(6-10), the gas flow rate is 100 mL / min - 200 mL / min, the discharge time is 10 min - 30 min, and the discharge power is 100 W - 600 W.

[0039] Step 2: Conduct plasma modification experiments according to the basic catalyst modification schemes to obtain modified catalyst samples corresponding to the b groups of basic catalyst modification schemes.

[0040] The process of the plasma modification experiment is as follows:

[0041] ①. Place the cerium-based catalyst sample into the reaction cavity of the microwave reaction system 3. The cerium-based catalyst is specifically a V / CeO2 composite material; the V / CeO2 composite material is obtained by impregnating V on the CeO2 support. The mass fraction of V in the V / CeO2 catalyst is 0.1 wt% - 0.6 wt%.

[0042] ②. The gas distribution system 5 supplies the reaction chamber of the microwave reaction system 3 with a mixed gas of Ar and H2, so that the volume ratio and gas flow rate of Ar and H2 set in the basic catalyst modification scheme are achieved in the reaction chamber; the microwave source 1 applies microwaves to the reaction chamber of the microwave reaction system 3, so that plasma discharge occurs in the reaction chamber of the microwave reaction system 3; the discharge time and discharge power of the plasma discharge are consistent with the set discharge time and discharge power in the basic catalyst modification scheme. After the plasma discharge ends, a modified catalyst sample corresponding to the basic catalyst modification scheme is obtained.

[0043] Step 3: Test the modified catalyst samples in group b to obtain the catalytic degradation efficiency and catalyst stability corresponding to the basic catalyst modification scheme in group b. The tests on the modified catalyst samples include BET, SEM, TEM, XRD, and XPS tests. Construct a basic experimental data set composed of the key parameters, catalytic degradation efficiency, and catalyst stability corresponding to the basic catalyst modification scheme in group b. Use the principal component analysis (PCA) method to optimize the main input parameters affecting the experimental results and eliminate the influence of irrelevant factors on the model accuracy.

[0044] Step 4: As Figure 2 shown, taking the mixing ratio of the gas atmosphere of Ar and H2, gas flow rate, plasma discharge time, and discharge power as input parameters, and the catalytic degradation rate of CVOCs and catalyst stability as output parameters, construct a parameter optimization model; use the basic experimental data set as the training set, set the initial weights, select the learning rate, and determine the optimal number of neurons in the hidden layer to be 9 by the trial-and-error method. Train the parameter optimization model through the backpropagation algorithm (Back Propagation), and the training process is as Figure 3 shown. The trained parameter optimization model is a three-layer BP neural network with a topological structure of 4-9-1.

[0045] Step 5: Use the root mean square error (RMSE) and coefficient of determination (R 2 ) to evaluate the performance of the parameter optimization model. In the case where the prediction performance of the parameter optimization model fails to reach the expected accuracy, use the genetic algorithm (Genetic Algorithm) to optimize the initial weights and thresholds to improve the global search ability and prediction performance of the parameter optimization model. Use the basic experimental data set as the training set, give different numbers of iterations under corresponding conditions, train and test the parameter optimization model, observe the network test accuracy, and determine the maximum number of iterations and expected values.

[0046] Step 6: Use the genetic algorithm (GA) to search for the key parameters corresponding to the desired (i.e., most compliant) CVOCs catalytic degradation rate and catalyst stability in the parameter optimization model. Finally, verify through experiments the CVOCs catalytic degradation rate and catalyst stability of the modified catalyst prepared with the obtained key parameters.

[0047] Step 7: Modify the cerium-based catalyst according to the four key parameters determined in Step 6 to obtain a modified cerium-based catalyst with enhanced anti-chlorine performance; the modification process is the same as that of the plasma modification test.

[0048] When the obtained modified cerium-based catalyst is used for CVOCs treatment, the concentration of the CVOCs to be treated is 800 ppm - 1200 ppm, the reaction temperature is set at 150°C - 250°C, the gas flow rate is 80 mL / min - 120 mL / min, the catalyst filling amount is 0.1 g - 0.4 g, and the catalytic treatment efficiency of CVOCs is 85% - 90%.

[0049] The modified cerium-based catalyst obtained by the above method is tested using a catalyst activity evaluation device.

[0050] As Figure 4 shown, the catalyst activity evaluation device includes a first mass flowmeter 7, a second mass flowmeter 8, a one-way valve 9, an ice-water bath stripping device 10, a mixing tank 11, a catalytic performance evaluation device 12, and a gas chromatograph 13. The modified cerium-based catalyst to be tested is in the catalytic performance evaluation device 12.

[0051] Air (21% O2 + 79% N2) is divided into two paths. The first path of air is input into the ice-water bath stripping device 10 through the first mass flowmeter 7 and the one-way valve 9; chlorobenzene is stored in a heat-insulating container in the ice-water bath stripping device 10, and the ice-water bath keeps chlorobenzene at a constant temperature during the stripping process. The rate of air stripping chlorobenzene is controlled by the mass flowmeter, and the one-way valve can prevent chlorobenzene from backflow. The second path of air is directly input into the mixing tank 11 through the second mass flowmeter 8; the air and the chlorobenzene stripped from the ice-water bath stripping device 10 are jointly output to the mixing tank 11 for mixing.

[0052] The air and chlorobenzene are mixed to simulate the state of chlorobenzene in the environment. To prevent chlorobenzene from condensing on the wall of the mixing tank and the pipeline, a heating tape is installed to keep the mixing tank and the pipeline warm, and the temperature is set at 80°C. The mixed gas is output from the mixing tank 11 to the tubular resistance furnace 12. The tubular resistance furnace heats the mixed gas, and the temperature of the tubular furnace is regulated by a temperature controller (heating program: the starting temperature is 60°C, the heating rate is 1°C / min, and the target temperature is 400°C).

[0053] The gas output from the tubular resistance furnace 12 is transported to the gas chromatograph 13. Online detection of the tail gas is carried out by gas chromatography. The inlet temperature is 120 °C, the temperature in the column oven is 80 °C, and the temperature of the FID detector is 200 °C. The total gas flow rate in the experimental design is 100 mL / min, and the reaction space velocity is 15000 h -1 , the concentration of chlorobenzene is about 1000 ppm, the inner diameter of the quartz tube is 8 mm, the catalyst filling amount is 0.2 g, and the particle size is 40 - 60 mesh.

[0054] Two specific examples are provided for the present invention below.

[0055] Example 1

[0056] Exhaust gas to be treated: A certain municipal waste incinerator generates polycyclic aromatic hydrocarbons and chlorinated aromatic compounds. After detection, in the waste incinerator, CBz (0.37 - 15.3 mg / Nm 3 ), CPs (0.29 - 10.2 mg / Nm 3 ), PAHs (1.89 - 38.9 mg / Nm 3 ) and other impurities. The main process parameters are: the inlet air temperature during the drying process is 120 °C, the drying time is 1 h, and the moisture content after drying is 0.5%. The obtained exhaust gas is concentrated by a zeolite rotor, the desorption temperature is 200 °C, and the concentration ratio is 10:1.

[0057] Modified cerium-based catalyst used: The V / CeO2 catalyst is adopted, loaded with 5 wt% of vanadium. The plasma modification conditions are set as follows: (1) Discharge gas: 40% Ar, 60% H2; (2) Gas flow rate: 150 mL / min; (3) Discharge time: 20 min; (4) Discharge power: 500 W.

[0058] After the exhaust gas is catalytically decomposed by the modified cerium-based catalyst, the treatment efficiencies of CBz and CPs reach 90.2% and 86.1% respectively, and the original treatment efficiencies are 60.2% and 54.7% respectively.

[0059] Example 2

[0060] Exhaust gas to be treated: At the exhaust gas discharge point of a certain workshop of a pharmaceutical enterprise, 9% of alkenes and alkanes, 19% of aromatic hydrocarbons, 36% of halogenated hydrocarbons, 6% of CVOCs, and 30% of other impurities are detected. The main process parameters: the inlet air temperature during the drying process is 120 °C, the drying time is 0.5 h, and the moisture content after drying is 0.5%. The obtained exhaust gas is concentrated by a zeolite rotor, the desorption temperature is 200 °C, and the concentration ratio is 15:1.

[0061] Modified cerium-based catalyst used: 5 wt% vanadium was loaded on the V / CeO2 catalyst. The plasma modification conditions were set as follows: (1) Discharge gas: 50% Ar, 50% H2; (2) Gas flow rate: 150 mL / min; (3) Discharge time: 20 min; (4) Discharge power: 100 W.

[0062] Meanwhile, the cerium-based catalyst before modification was set as the control group; the variation of the treatment efficiency of the cerium-based catalyst before and after modification for CVOCs waste gas with time is as Figure 5 shown; it can be seen from Figure 5 that the treatment efficiency of the cerium-based catalyst before modification was 80% after 450 h of treatment, and the treatment efficiency decreased rapidly by 65% after 500 h; while the treatment efficiency of the modified cerium-based catalyst for CVOCs reached 93.1%, and within 700 h, the treatment efficiency of CVOCs could be maintained at around 90%.

Claims

1. A method for modifying a cerium-based catalyst with enhanced plasma anti-chlorine performance, characterized in that: It includes the following steps: Step 1: Put the cerium-based catalyst to be processed into a plasma discharge device; the plasma discharge device uses a microwave plasma modification device; Step 2: Start the plasma discharge device, and perform microwave plasma discharge under the atmosphere of a mixed gas of Ar and H2 to enhance the chlorine resistance of the cerium-based catalyst; during the operation of the plasma discharge device, the volume ratio of Ar to H2 in the gas atmosphere is (1-5):(6-10), the gas flow rate is 100 mL / min to 200 mL / min, and the discharge time is 10 min to 30 min; The cerium-based catalyst is specifically a V / CeO2 composite material; the V / CeO2 composite material is obtained by loading V on a CeO2 support through an impregnation method; the mass fraction of V in the V / CeO2 catalyst is 0.1 wt%-0.6 wt%; Take the mixing ratio of Ar and H2 in the gas atmosphere, gas flow rate, plasma discharge time, and discharge power as the four key parameters of the plasma discharge device; the four key parameters are determined by the following method: (1) Formulate b groups of basic catalyst modification schemes, 1≤b≤10; each group of basic catalyst modification schemes includes corresponding four key parameters; (2) Respectively perform plasma modification on the cerium-based catalyst according to the b groups of basic catalyst modification schemes to obtain modified catalysts corresponding to the b groups of basic catalyst modification schemes; Test the b groups of modified catalysts to obtain the catalytic degradation efficiency and catalyst stability corresponding to the b groups of basic catalyst modification schemes; Construct a basic experimental data set composed of the key parameters, catalytic degradation efficiency, and catalyst stability corresponding to the b groups of basic catalyst modification schemes; (3) Take the mixing ratio of Ar and H2 in the gas atmosphere, gas flow rate, plasma discharge time, and discharge power as input parameters, and the catalytic degradation rate and catalyst stability of CVOCs as output parameters to construct a parameter optimization model; the parameter optimization model uses a BP neural network; Use the basic experimental data set to train the parameter optimization model; (4) Use the parameter optimization model to simulate the catalytic degradation efficiency and catalyst stability corresponding to different key parameter combinations, and screen out the key parameter combinations that meet the preset requirements of catalytic degradation efficiency and catalyst stability.

2. The method for modifying a cerium-based catalyst with enhanced chlorine resistance by plasma according to claim 1, characterized in that: During the operation of the plasma discharge device, the discharge power is 100W to 600W.

3. A method for modifying a cerium-based catalyst with enhanced chlorine resistance by plasma, characterized in that: In step (3), the parameter optimization model is trained by the error backpropagation algorithm; after step (3) is executed, the performance of the trained parameter optimization model is evaluated using the root mean square error and determination coefficient; in the case where the prediction performance of the parameter optimization model does not reach the desired accuracy, use the genetic algorithm to optimize the initial weights and thresholds of the parameter optimization model, and adjust the maximum number of iterations; then, retrain the parameter optimization model until the prediction performance of the parameter optimization model reaches the desired accuracy.

4. A method for modifying a cerium-based catalyst with enhanced chlorine resistance by plasma, characterized in that: The parameter optimization model uses a three-layer BP neural network with a topological structure of 4-9-1, and the number of neurons in the hidden layer is 9.

5. A method for modifying a cerium-based catalyst with enhanced chlorine resistance by plasma, characterized in that: The described microwave plasma modification device includes a microwave source (1), a microwave transmission system (2), a microwave reaction system (3), a vacuum system (4), and a gas distribution system (5); the microwave output port of the microwave source (1) is connected to the microwave input port of the microwave transmission system (2); the microwave output port of the microwave transmission system (2) is connected to the input port of the microwave reaction system (3); the gas output port of the gas distribution system (5) is connected to the gas input port of the microwave reaction system (3); the gas distribution system (5) is used to supply a mixed gas of hydrogen and argon to the reaction chamber of the microwave reaction system (3); the pumping port of the vacuum system (4) is connected to the vacuum interface of the microwave reaction system (3).

6. The method for modifying a cerium-based catalyst with enhanced chlorine resistance by plasma according to claim 5, characterized in that: The input port of the described microwave reaction system (3) is provided with a coupling cavity; the coupling cavity is used to convert the microwave from the TE operating mode to the TM operating mode.

7. A method for modifying a cerium-based catalyst with enhanced chlorine resistance by plasma, characterized in that: A cooling water channel is surrounded around the reaction chamber in the described microwave reaction system (3); the cooling water channel is connected to an external cooling water system (6).

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