Two-step packaged noble metal-based molecular sieve catalyst and application thereof in oxidative degradation of 1, 2-dichloroethane

Abstract

The invention relates to a two-step packaged noble metal-based molecular sieve catalyst and application thereof in oxidative degradation of 1, 2-dichloroethane, and belongs to the field of catalysts. The method comprises the following steps: selecting ZSM-5 as a catalyst carrier, firstly encapsulating noble metal Ru in ZSM-5, and calcining; then loading transition metal on the surface as a second component, and calcining; the non-noble metal element comprises one or more of cobalt (Co), copper (Cu), iron (Fe) and cerium (Ce). When the reaction temperature is 350 DEG C, the catalyst can completely degrade 1, 2-dichloroethane in industrial tail gas to generate CO2, H2O and HCl, and the yield of by-products (Cl2 and chlorinated hydrocarbon) is less than 5%.

Description

Technical Field

[0001] The present application relates to the field of catalytic degradation, and particularly to a method for catalytically degrading 1,2-dichloroethane by a two-step encapsulation noble metal-based catalyst. Background Art

[0002] 1,2-Dichloroethane (1,2-DCE) is an important organic chemical raw material with a broad market space and is widely used in fields such as polyvinyl chloride (PVC), pesticides, dyes, and pharmaceutical intermediates. At present, the main preparation methods of 1,2-dichloroethane are traditional processes such as the chlorination method, but these methods have certain problems in terms of safety and environmental protection. In recent years, with the promotion of the concept of green chemistry, the development of more environmentally friendly and efficient production processes has become a research hotspot.

[0003] During the production process of 1,2-dichloroethane, tail gases containing pollutants such as polyvinyl chloride and dichloroethane are generated, which pose hazards to the atmospheric environment and human health. Research shows that 1,2-dichloroethane has certain toxicity, and long-term exposure may lead to nervous system damage and liver and kidney dysfunction. In addition, 1,2-dichloroethane is difficult to degrade in the environment, which will pollute water bodies and soil, thereby affecting the ecosystem. Therefore, how to quickly, efficiently, and safely eliminate 1,2-dichloroethane in industrial tail gases is crucial for human health and ecological environment protection.

[0004] In the prior art, the technologies for treating chlorine-containing organic pollutants such as 1,2-dichloroethane mainly include the adsorption method and the catalytic oxidation method. Among them, the adsorption method can only enrich pollutant molecules and cannot achieve degradation. The catalytic oxidation method is considered to be the most promising means for removing chlorine-containing organic pollutants because of its advantages such as low combustion temperature, high treatment efficiency, and good safety. The key lies in the development of catalysts. In recent years, catalysts with high catalytic activity at low temperatures have received extensive attention.

[0005] CN118925754A reports a Ru / SnO2-(SO4 2- ) x catalyst for the catalytic combustion of various CVOCs. This catalyst can completely oxidize 1,2-dichloroethane to hydrogen chloride or chlorine, carbon dioxide, and water at a lower temperature, and achieve up-to-standard discharge through alkali solution absorption. However, its noble metal loading is 3%, and considering the high price of noble metals, the catalyst cost is relatively high, which limits its wide application.

[0006] CN116139912A reports a preparation method of a monolithic catalyst for rapid in-situ encapsulation of noble metals. This method can encapsulate noble metals in a honeycomb ceramic carrier through an encapsulation technology, greatly improving the catalytic performance for dichloromethane, and this encapsulation technology greatly improves the dispersion of noble metals.

[0007] CN111203241A uses the composite of Mn and Ce oxides to treat organochlorine waste gas, but it can only treat organochlorine waste gas with a relatively low space velocity (200 - 2000 h -1 ), and transition metal oxides are more likely to be attacked by chlorine. Their activity and long-term stability are far inferior to noble metal catalysts. However, as the second active component of noble metal-based catalysts to reduce the noble metal dosage and promote product selectivity is a potential technology.

[0008] In summary, the existing publicly disclosed catalysts still cannot fully meet the requirements of efficient, low-cost, and environmentally friendly degradation of 1,2-dichloroethane. Developing more efficient and low-cost catalysts remains the key research direction at present. Summary of the Invention

[0009] To solve the problems of high noble metal loading and reduced utilization rate due to being covered by the composite with the second component, the present invention provides a preparation method and application of a two-step encapsulated noble metal catalyst to solve the problem of 1,2-dichloroethane tail gas emission. This method improves the dispersion of noble metals through encapsulation, and introduces transition metals as the second component on the surface, while enhancing the utilization rates of noble metals and transition metals. It can efficiently treat 1,2-dichloroethane tail gas with a low noble metal loading, convert it into CO2, H2O, and HCl, and simultaneously achieve a by-product yield of less than 5%.

[0010] A two-step encapsulated noble metal-based catalyst, characterized in that ZSM-5 is selected as the catalyst carrier. First, noble metal Ru is encapsulated in ZSM-5 and calcined; then a transition metal is loaded on the surface as the second component and calcined; wherein noble metal Ru accounts for 0.1 - 1% of the catalyst's mass, and the non-noble metal component accounts for 3 - 10% of the catalyst's mass. The non-noble metal elements include one or more of cobalt (Co), copper (Cu), iron (Fe), and cerium (Ce) elements.

[0011] The above preparation method of a two-step encapsulated noble metal catalyst includes the following steps:

[0012] (1) Mix the aluminum source and the template agent in water and stir evenly, then introduce the sodium source, and introduce the above solution into the silicon source that has been vigorously stirred in advance to a gel state;

[0013] (2) Place it in an autoclave and perform the first crystallization at a certain temperature to generate a part of crystal seeds;

[0014] (3) Introduce the pre-prepared noble metal salt solution into the autoclave system of step (2), stir evenly, and perform the second crystallization at a certain temperature;

[0015] (4) Wash the samples obtained in the kettle with distilled water and ethanol several times, such as three times, and place them in a vacuum drying oven for drying for a period of time, and then transfer them to a muffle furnace for full calcination;

[0016] (5) Stir and age a certain amount of the above samples with a non-noble metal salt solution at room temperature;

[0017] (6) Transfer to a rotary evaporator to evaporate to dryness, and then transfer to a vacuum drying oven for drying for a period of time;

[0018] (7) Transfer the dried sample into a muffle furnace and calcine it fully at a certain temperature.

[0019] The aluminum source described in step (1) is one or more of aluminum chloride (AlCl3), aluminum sulfate (Al2(SO4)3), sodium aluminate (NaAlO2), and aluminum isopropoxide (C9H 21 AlO3).

[0020] The template agent described in step (1) is one of tetrapropylammonium hydroxide, tetrapropylammonium bromide, and tetrapropylammonium chloride.

[0021] The sodium source described in step (1) is a mixture of sodium hydroxide (NaOH) and one or more of sodium chloride (NaCl) and sodium bromide (NaBr), and preferably includes at least sodium hydroxide (NaOH);

[0022] The silicon source described in step (1) is one of silica sol and tetraethyl orthosilicate.

[0023] The molar ratio range of each component in the gel-like solution described in step (1) is:

[0024] Further, in step (1), Al:template agent = 0.04 - 0.06:1; Al:NaOH = 0.1 - 0.4:1; Al:Na = 0.05 - 0.2:1; Al:Si = 12 - 18:1; Al:H2O = 1:500 - 1000; the above are molar ratios.

[0025] In step (2), the first crystallization temperature is 80 - 120 °C, and the crystallization time is 20 - 28 h.

[0026] In step (3), the noble metal salt solution is an aqueous solution of a noble metal salt, with a concentration of 0.001 - 0.01 mol / L, and the noble metal salt is one or more of ruthenium nitrate, ruthenium chloride, and ruthenium sulfate; preferably, the molar ratio of Al:Ru = 2 - 4:1.

[0027] The second crystallization temperature is 150 - 190 °C, and the crystallization time is 45 - 50 h.

[0028] In step (5), the non-noble metal salt solution is an aqueous solution of a non-noble metal salt, with a concentration of 0.01 - 0.1 mol / L; the non-noble metal elements include one or more of cobalt (Co), copper (Cu), iron (Fe), and cerium (Ce); the non-noble metal salt includes one of nitrates, chlorides, and sulfates. And the molar ratio of Al: non-noble metal is = 1:3 - 5.

[0029] There are no special requirements for the stirring time, stirring temperature, drying temperature, drying time, etc. in the above steps. The specific conditions are as follows: the stirring temperature is, for example but not limited to, 20 - 60 °C; the stirring time is, for example but not limited to, 2 - 48 h; the drying temperature is, for example but not limited to, 80 - 120 °C, and the drying time is, for example but not limited to, 12 - 36 h. The calcination temperature in the muffle furnace is, for example but not limited to, 500 - 600 °C.

[0030] The noble metal-based catalyst synthesized by the above two-step method is used to degrade 1,2-dichloroethane in industrial tail gas. At 350 °C, 100% conversion of 1,2-dichloroethane pollutants in industrial tail gas can be achieved, converting it into CO2, H2O, and HCl, and the yield of by-products (such as Cl2 and chlorinated hydrocarbons) is less than 5%.

[0031] The beneficial effects of the present invention are as follows: Example 1 provided by the present invention can achieve green, environmentally friendly, and efficient degradation of 1,2-dichloroethane in industrial tail gas, converting it into CO2, H2O, and HCl at 350 °C, while achieving a by-product yield of less than 5%. The method for preparing the catalyst is simple to operate, harmless to humans and the environment, convenient for industrial application, and has good application prospects. Description of the Drawings

[0032] Figure 1 It is the X-ray diffraction pattern of the catalyst prepared in Example 1. Detailed Embodiments

[0033] The following are specific examples of the present invention, and the technical solutions of the present invention are further elaborated in combination with the examples. These examples do not limit the scope of the present invention in any way.

[0034] The reagents, methods, and equipment used in the present invention are all conventional reagents, methods, and equipment in the technical field, unless otherwise specified.

[0035] Catalyst performance test method:

[0036] 150 mg of the catalyst was granulated and loaded into a quartz reaction tube with an inner diameter of 6 mm. The reaction was carried out at a total gas flow rate of 100 mL / min, where the concentration of 1,2-dichloroethane (1,2-DCE) was 1000 ppm, the oxygen content was 10%, and nitrogen was used as the balance gas. Under these conditions, the volume space velocity of the mixed gas was 40,000 h-1. In the reaction temperature range of 250 - 500 °C, sampling and analysis were performed every 50 °C using a gas chromatography-mass spectrometry (GC-MS) device to study the catalytic degradation performance of 1,2-dichloroethane.

[0037] The analytical methods for Cl2 and HCl in the gas were as follows: The gas at the reactor outlet was absorbed by a (12.5 mmol / L) NaOH aqueous solution for 0.5 h each time, and then the Cl2 concentration was titrated using 0.01 mol / L ammonium ferrous sulfate and N,N-diethyl-p-phenylenediamine as an indicator. - The concentration of Cl was detected by a chloride ion selective electrode.

[0038] The conversion of 1,2-DCE and the product yields were calculated using the following formulas:

[0039]

[0040] In the formula: [1,2-DCE] in is the inlet concentration of 1,2-dichloroethane; [1,2-DCE] out is the outlet concentration of 1,2-dichloroethane; [CO2], [HCl], [Cl2] and [C x H y Cl z are the outlet concentrations of carbon dioxide, hydrogen chloride, chlorine and chlorine-containing organic compounds, respectively.

[0041] Example 1

[0042] Dissolve 0.3 g of aluminum isopropoxide and 6.0 g of tetrapropylammonium chloride (TPACl) in 20 ml of water, stir for 20 min at room temperature, then add 0.33 g of NaCl and 0.3 g of NaOH, and stir vigorously for 20 minutes. Transfer the above-obtained solution to 6.25 g of vigorously stirred silica sol in a gel state (Al:TPACl = 0.054:1, Al:NaOH = 0.2:1, Al:Na = 0.11:1, Al:Si = 14:1, Al:H2O = 1:756). Introduce it into a high-pressure reactor and crystallize at a low temperature of 100 °C for 24 h. Introduce 100 ml of RuCl3 solution (RuCl3 = 0.005 mol / L, Al:Ru = 2.94:1) into the obtained sample, and transfer it to a pressure reactor and crystallize at 170 °C for 48 h. The obtained sample is washed 5 times with deionized water and ethanol respectively. Then transfer it to a vacuum oven at 80 °C and dry overnight. The dried sample is calcined in a muffle furnace at 550 °C with a heating rate of 5 °C / min for 6 h. Take 4 g of the above-obtained sample and mix it with 100 ml of Co(NO3)2 solution (Co(NO3)2 = 0.05 mol / L, Al:Co = 1:3.4) and stir for 6 h. Transfer the above solution to a rotary evaporator and evaporate to dryness at 80 °C, and transfer it to a vacuum drying oven at 80 °C and dry for 6 h. The dried sample is transferred to a muffle furnace and calcined at 550 °C with a heating rate of 5 °C / min for 6 h to obtain the two-step encapsulated Co / Ru@ZSM-5 catalyst (the mass of Ru and Co atoms based on the total catalyst mass are 0.5% and 5% respectively).

[0043] Example 2

[0044] Dissolve 0.3 g of aluminum isopropoxide and 6.0 g of tetrapropylammonium chloride (TPACl) in 20 ml of water, stir for 20 min at room temperature, then add 0.33 g of NaCl and 0.3 g of NaOH, and stir vigorously for 20 minutes. Transfer the above-obtained solution to 6.25 g of vigorously stirred silica sol in a gel state (Al:TPACl = 0.054:1, Al:NaOH = 0.2:1, Al:Na = 0.11:1, Al:Si = 14:1, Al:H2O = 1:756). Introduce it into a high-pressure reactor and crystallize at 100 °C for 24 h. Introduce 100 ml of RuCl3 solution (RuCl3 = 0.005 mol / L, Al:Ru = 2.94:1) into the obtained sample, and transfer it to a pressure reactor and crystallize at 170 °C for 48 h. Wash the obtained sample 5 times with deionized water and ethanol respectively. Then transfer it to a vacuum oven at 80 °C and dry overnight. The dried sample is calcined in a muffle furnace at 550 °C with a heating rate of 5 °C / min for 6 h. Take 4 g of the above-obtained sample and mix it with 100 ml of Ce(NO3)3 solution (Ce(NO3)3 = 0.05 mol / L, Al:Ce = 1:3.4) and stir for 6 h. Transfer the above solution to a rotary evaporator and evaporate to dryness at 80 °C, and transfer it to a vacuum drying oven at 80 °C and dry for 6 h. The dried sample is transferred to a muffle furnace and calcined at 550 °C with a heating rate of 5 °C / min for 6 h to obtain the two-step encapsulated Ce / Ru@ZSM-5 catalyst (the mass percentages of Ru and Ce atoms based on the total catalyst mass are 0.5% and 5% respectively).

[0045] Example 3

[0046] Dissolve 0.3 g of aluminum isopropoxide and 6.0 g of tetrapropylammonium chloride (TPACl) in 20 ml of water, stir for 20 min at room temperature, then add 0.33 g of NaCl and 0.3 g of NaOH, stir vigorously for 20 minutes, and transfer the above-obtained solution to 6.25 g of vigorously stirred silica sol in a gel state (Al:TPACl = 0.054:1, Al:NaOH = 0.2:1, Al:Na = 0.11:1, Al:Si = 14:1, Al:H2O = 1:756). Introduce it into a high-pressure reactor and crystallize at a low temperature of 100 °C for 24 h. Introduce 100 ml of RuCl3 solution (RuCl3 = 0.005 mol / L, Al:Ru = 2.94:1) into the obtained sample, and transfer it to a pressure reactor and crystallize at 170 °C for 48 h. The obtained sample is washed 5 times with deionized water and ethanol respectively. Then transfer it to a vacuum oven at 80 °C and dry overnight. The dried sample is calcined in a muffle furnace at 550 °C with a heating rate of 5 °C / min for 6 h. Take 4 g of the above-obtained sample and mix it with 100 ml of Fe(NO3)3 solution (Fe(NO3)3 = 0.05 mol / L, Al:Fe = 1:3.4) and stir for 6 h. Transfer the above solution to a rotary evaporator and evaporate to dryness at 80 °C, then transfer it to a vacuum drying oven at 80 °C and dry for 6 h. The dried sample is transferred to a muffle furnace and calcined at 550 °C with a heating rate of 5 °C / min for 6 h to obtain the two-step encapsulated Fe / Ru@ZSM-5 catalyst (the mass of Ru and Fe atoms is 0.5% and 5% respectively based on the mass of the overall catalyst).

[0047] Example 4

[0048] Dissolve 0.3 g of aluminum isopropoxide and 6.0 g of tetrapropylammonium chloride (TPACl) in 20 ml of water, stir for 20 min at room temperature, then add 0.33 g of NaCl and 0.3 g of NaOH, and stir vigorously for 20 minutes. Transfer the obtained solution to 6.25 g of vigorously stirred silica sol in the gel state (Al:TPACl = 0.054:1, Al:NaOH = 0.2:1, Al:Na = 0.11:1, Al:Si = 14:1, Al:H2O = 1:756). Introduce it into a high-pressure reactor and crystallize at a low temperature of 100 °C for 24 h. Introduce 100 ml of RuCl3 solution (RuCl3 = 0.005 mol / L, Al:Ru = 2.94:1) into the obtained sample, and transfer it to a pressure reactor and crystallize at 170 °C for 48 h. Wash the obtained sample 5 times with deionized water and ethanol respectively. Then transfer it to a vacuum oven at 80 °C and dry overnight. Calcinate the obtained dried sample in a muffle furnace at 550 °C with a heating rate of 5 °C / min for 6 h. Take 4 g of the above-obtained sample and mix it with 100 ml of Cu(NO3)2 solution (Cu(NO3)2 = 0.05 mol / L, Al:Cu = 1:3.4) and stir for 6 h. Transfer the above solution to a rotary evaporator and evaporate to dryness at 80 °C, and transfer it to a vacuum drying oven at 80 °C and dry for 6 h. Transfer the dried sample to a muffle furnace and calcinate at 550 °C with a heating rate of 5 °C / min for 6 h to obtain a two-step encapsulated Cu / Ru@ZSM-5 catalyst (the mass percentages of Ru and Cu atoms based on the overall catalyst mass are 0.5% and 5% respectively).

[0049] Comparative example

[0050] Dissolve 0.3 g of aluminum isopropoxide and 6.0 g of tetrapropylammonium chloride (TPACl) in 20 ml of water, stir for 20 min at room temperature, then add 0.33 g of NaCl and 0.3 g of NaOH, stir vigorously for 20 minutes, and transfer the obtained solution to 6.25 g of vigorously stirred silica sol in the gel state (Al:TPACl = 0.054:1, Al:NaOH = 0.2:1, Al:Na = 0.11:1, Al:Si = 14:1, Al:H2O = 1:756). Introduce it into a high-pressure reactor, crystallize at a low temperature of 100 °C for 24 h, then transfer it to a high-pressure reactor and crystallize at 170 °C for 48 h. The obtained samples are washed 5 times with deionized water and ethanol respectively. Then transfer it to a vacuum oven at 80 °C and dry overnight. The dried sample is calcined in a muffle furnace at 550 °C with a heating rate of 5 °C / min for 6 h. Take 4 g of the obtained sample above and mix and stir it with 50 ml of RuCl3 solution (RuCl3 = 0.01 mol / L, Al:Ru = 2.94:1) and 50 ml of Co(NO3)2 solution (Co(NO3)2 = 0.05 mol / L, Al:Co = 1:3.4) for 6 h. Transfer the above solution to a rotary evaporator and evaporate to dryness at 80 °C, then transfer it to a vacuum drying oven at 80 °C and dry for 6 h. The dried sample is transferred to a muffle furnace and calcined at 550 °C with a heating rate of 5 °C / min for 6 h to obtain the supported Co-Ru / ZSM-5 catalyst (the atomic masses of Ru and Co are 0.5% and 5% respectively based on the mass of the whole catalyst).

[0051] Experimental results

[0052] Table 1 Conversion rate data of 1,2-dichloroethane for Examples 1-4 and Comparative Example 1

[0053]

[0054] Table 2 Product yield data of Examples 1-4 and Comparative Example 1 when the reaction temperature is 350 °C

[0055]

[0056] Table 1 shows the data of the conversion rate of 1,2-dichloroethane catalyzed by different catalysts varying with temperature under the same conditions for Examples 1-4 and the comparative example. Table 2 shows the product yield data of each catalyst when the reaction temperature is 350 °C.

[0057] As Figure 1 The XRD diffraction pattern measured in Example 1 shows the characteristic peaks of the MFI-type molecular sieve, and the peak shape is obvious, proving that the crystallinity of the sample is good, and no characteristic peaks of RuO2 and Co3O4 are observed in the XRD pattern, proving that Ru and Co are highly dispersed on the sample

[0058] It can be seen from the data of Examples 1-4 and the comparative example that the noble metal-based catalysts encapsulated by the two-step method (Examples 1, 2, 3, and 4) can completely convert 1,2-dichloroethane at 350 °C, and the yields of by-products (Cl2, chlorinated hydrocarbons) are much lower than those of the supported noble metal-based catalyst (Comparative Example 1). Therefore, the noble metal-based catalyst encapsulated by the two-step method has better 1,2-dichloroethane degradation performance. Comparing the data of Example 1 and Comparative Example 1, under the same other conditions, when Example 1 reached 100% conversion of 1,2-dichloroethane at 350 °C, the HCl yield was as high as 98.7%, and no by-product Cl2 was generated. And only a small amount of chlorinated hydrocarbons were generated (1.2%), while Comparative Example 1 failed to reach 100% conversion of 1,2-dichloroethane at 350 °C, and the chlorine-containing by-products generated were close to 40%. Therefore, in Example 1, the noble metal can be encapsulated inside the carrier by the two-step method, reducing the damage of reactants to the active sites, while in Comparative Example 1, the noble metal was loaded on the surface of the carrier, enhancing the coverage of Co on Ru and reducing the catalytic performance.

[0059] It can be seen from the data comparison among Examples 1, 2, 3, and 4 that at the same temperature, the activity order of each catalyst is: Example 1 > Example 2 > Example 3 > Example 4, among which, Example 1 can reach a conversion rate of more than 100% at 350 °C. This shows that the noble metal-based catalyst encapsulated by the two-step method is significantly superior to the interaction of Ce, Fe, and Cu when combined with the action of Co.

[0060] The above has made a detailed description in conjunction with the embodiments of the present invention, but the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those of ordinary skill in the art, various changes can be made without departing from the purpose of the present invention.

[0061] Matters not described in the present invention are applicable to the prior art.

Claims

1. A two-step method for encapsulating a noble metal-based catalyst, characterized in that: ZSM-5 is selected as the catalyst carrier, and the noble metal Ru is first encapsulated in the ZSM-5 and calcined; then a transition metal is loaded on the surface as a second component and calcined; the non-noble metal elements include one or more of cobalt (Co), copper (Cu), iron (Fe) and cerium (Ce) elements.

2. A two-step method for encapsulating a noble metal-based catalyst according to claim 1, characterized in that: The noble metal Ru accounts for 0.1-1% of the catalyst weight, and the non-noble metal components account for 3-10% of the catalyst weight.

3. A two-step method for preparing a precious metal-based catalyst encapsulation according to claim 1 or 2, characterized in that: The following steps are involved: (1) After mixing and stirring the aluminum source and the template agent in water, a sodium source is introduced, and the above solution is introduced into a silicon source that has been vigorously stirred in advance to a gel state; (2) placing the mixture in an autoclave and performing a first crystallization at a certain temperature to produce a portion of seed crystals; (3) introducing the noble metal salt solution prepared in advance into the autoclave system of step (2), stirring evenly, and performing a second crystallization at a certain temperature; (4) washing the sample obtained in the kettle with distilled water and ethanol for multiple times, for example, three times, and drying it in a vacuum drying oven for a period of time, and then transferring it to a muffle furnace for full calcination; (5) fully stirring and aging a certain amount of the sample and a non-precious metal salt solution at room temperature; (6) transferring to a rotary evaporator to evaporate to dryness, and then transferring to a vacuum drying oven to dry for a period of time; (7) The dried sample is transferred into a muffle furnace and calcined at a certain temperature.

4. The method according to claim 3, characterized in that The aluminum source in step (1) is aluminum chloride (AlCl3), aluminum sulfate (Al2(SO4)3), sodium aluminate (NaAlO2), aluminum isopropoxide (C9H 21 AlO3) or more; The template agent in step (1) is one of tetrapropylammonium hydroxide, tetrapropylammonium bromide and tetrapropylammonium chloride; The sodium source in step (1) is a mixture of sodium hydroxide (NaOH) and one or more of sodium chloride (NaCl) and sodium bromide (NaBr), preferably including at least sodium hydroxide (NaOH); The silicon source in step (1) is one of silica sol and tetraethyl orthosilicate; The molar ratio of each component in the gel solution of step (1) is as follows: In the further step (1), Al:template=0.04-0.06:1; Al:NaOH=0.1-0.4:1; Al:Na=0.05~0.2:1; Al:Si=12~18:1; Al:H2O=1:500~1000; the above are molar ratios.

5. The method according to claim 3, characterized in that In step (2), the first crystallization temperature is 80-120° C. and the crystallization time is 20-28 hours.

6. The method according to claim 3, characterized in that The noble metal salt solution in step (3) is an aqueous solution of a noble metal salt, with a concentration of 0.001 to 0.01 mol / L, and the noble metal salt is one or more of Ru nitrate, chloride, and sulfate; preferably, the molar ratio of Al:Ru is 2 to 4:1; The second crystallization temperature is 150-190°C and the crystallization time is 45-50h.

7. The method according to claim 3, characterized in that The non-precious metal salt solution in step (5) is an aqueous solution of non-precious metal salt, with a concentration of 0.01-0.1 mol / L; the non-precious metal element includes one or more of cobalt (Co), copper (Cu), iron (Fe) and cerium (Ce); the non-precious metal salt includes one of nitrate, chloride and sulfate. And the molar ratio of Al: non-precious metal is 1:3-5.

8. The method according to claim 3, characterized in that There are no special requirements for the stirring time, stirring temperature, drying temperature and drying time in the above steps. The specific conditions are as follows: the stirring temperature is, for example, but not limited to, 20 to 60°C; the stirring time is, for example, but not limited to, 2 to 48 hours; the drying temperature is, for example, but not limited to, 80 to 120°C, and the drying time is, for example, but not limited to, 12 to 36 hours. The muffle furnace calcination temperature is, for example, but not limited to, 500 to 600°C.

9. Use of the two-step encapsulated noble metal-based catalyst according to claim 1 or 2 for degrading 1,2-dichloroethane in industrial tail gas.

10. The use according to claim 9 is used for degrading 1,2-dichloroethane in industrial tail gas, and can achieve 100% conversion of 1,2-dichloroethane pollutants in industrial tail gas at 350° C., converting it into CO2, H2O and HCl, and the yield of by-products (such as Cl2, chlorinated hydrocarbons) is less than 5%.

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