Preparation method and application of monatomic catalyst for catalytic degradation of ethanethiol

Abstract

The invention discloses a preparation method and application of a monatomic catalyst for catalytic degradation of ethanethiol, and belongs to the technical field of organic sulfur pollutant treatment.The atomic-scale dispersion of Ce species is achieved through HY molecular sieve FAU type topological structure constraint and cerium loading capacity limitation, the catalyst shows atomic-scale active sites, and the catalytic degradation of ethanethiol is achieved. The conversion path of ethanethiol can be accurately regulated and controlled, and efficient degradation of ethanethiol is realized; the topological confinement effect guarantees the stability of the monatomic catalyst, and the HY molecular sieve pore channel restrains migration of Ce atoms and inhibits agglomeration of Ce metal, so that the monatomic catalyst shows good anti-sintering ability, and at the same time, sulfur poisoning and carbon deposition rate are slowed down.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic sulfur pollutant treatment, and particularly relates to a preparation method and application of a single-atom catalyst for catalytic degradation of ethanethiol. Background Art

[0002] Ethanethiol is a volatile organic sulfur compound with a strong pungent odor. It is a colorless transparent liquid at room temperature, with a boiling point of 36.2 °C, slightly soluble in water (solubility is about 1.5 g / L at 25 °C), volatile, flammable and explosive (flash point -18 °C). It is widely sourced from petroleum refining, natural gas odorization processes, pesticide / pharmaceutical industries, and biomass decay processes such as landfills and sewage treatment plants. It poses significant hazards to the environment and health: at low concentrations (threshold 0.001 ppm), it can cause odor pollution, and long-term exposure can lead to headaches, respiratory damage, and central nervous system poisoning. At the same time, it participates in atmospheric photochemical reactions to generate ozone and secondary organic aerosols, exacerbating environmental pollution. Therefore, the development of new technologies for efficiently removing ethanethiol from malodorous gases is crucial for both humans and the environment.

[0003] Currently, the treatment technologies for ethanethiol mainly include adsorption, catalytic oxidation, catalytic decomposition, and photocatalysis. The adsorption method physically adsorbs ethanethiol through activated carbon, molecular sieves, or metal-organic framework materials, but it has limitations such as low adsorption capacity (usually less than 100 mg / g), difficult regeneration (high-temperature desorption is required), and inability to treat high-concentration or continuously discharged waste gases. The photocatalysis method uses semiconductor materials such as TiO2 and g-C3N4 to generate reactive oxygen species under ultraviolet / visible light excitation to degrade ethanethiol, but it is limited by low quantum efficiency (usually less than 10%), slow reaction rate, and the possible formation of toxic intermediate products such as thioethers. The catalytic oxidation method completely oxidizes ethanethiol to CO2, H2O, and SO4 in the presence of oxygen through noble metal (such as Pt, Pd / Al2O3) or transition metal oxide (such as CuO-CeO2, Co3O4) catalysts 2- and has the advantages of complete reaction and no secondary pollution, especially suitable for the treatment of medium- and high-concentration waste gases. However, traditional thermal catalysis requires high-temperature conditions, high energy consumption, noble metal catalysts are prone to sulfur poisoning and have a short lifespan, while transition metal oxides, although low-cost, face problems such as insufficient low-temperature activity and carbon deposition deactivation. Existing technologies generally face challenges such as weak sulfur resistance, difficulty in balancing low-temperature activity and stability, and interference from complex waste gas components (such as coexisting H2O, CO2, etc.). Summary of the Invention

[0004] To solve the above technical problems, the present invention proposes a preparation method and application of a single-atom catalyst for catalytic degradation of ethanethiol.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] One of the technical solutions of the present invention:

[0007] The present invention provides a preparation method of a single-atom catalyst for catalytic degradation of ethanethiol. Using HY zeolite as a carrier, cerium is loaded by the incipient wetness impregnation method and calcined to obtain the single-atom catalyst for catalytic degradation of ethanethiol; wherein, the loading amount of cerium is < 2 wt%.

[0008] The HY zeolite has a FAU-type topological structure. The present invention realizes the atomic dispersion of Ce species through the constraint of the FAU-type topological structure of the HY zeolite and the limitation of the cerium loading amount, enabling the catalyst to exhibit atomic-level active sites, which can precisely regulate the conversion path of ethanethiol and achieve the efficient degradation of ethanethiol. In the single-atom catalyst of the present invention, Ce exhibits 100% atomic exposure. At the same time, the electron transfer between cerium atoms and the HY zeolite enhances the adsorption energy of ethanethiol molecules, reduces the activation energy barrier, and shows excellent catalytic decomposition ability of ethanethiol. In addition, the topological confinement effect ensures the stability of the single-atom catalyst. The pore channels of the HY zeolite restrict the migration of Ce atoms, inhibit the agglomeration of Ce metal, enabling the single-atom catalyst to exhibit good anti-sintering ability, while slowing down the sulfur poisoning and carbon deposition rates. In short, the single-atom catalyst of the present invention has excellent anti-sulfur poisoning and carbon deposition characteristics.

[0009] Further, before the HY zeolite is loaded with cerium, it also includes a heat treatment step.

[0010] Further, the preparation method of the single-atom catalyst for catalytic degradation of ethanethiol includes the following steps:

[0011] Heat-treat the HY zeolite to obtain a HY zeolite carrier;

[0012] Immerse the HY zeolite carrier in an aqueous solution containing a soluble cerium salt, stir, dry and then calcine to obtain the single-atom catalyst for catalytic degradation of ethanethiol, and the loading amount of cerium in the single-atom catalyst for catalytic degradation of ethanethiol is < 2 wt%.

[0013] Exemplarily, the silica-alumina ratio of the HY zeolite is 35, that is, n(SiO2) / n(Al2O3) = 35.

[0014] Further, the temperature of the heat treatment is 500 - 600 °C, and the time is 250 - 350 min. Preferably, the temperature of the heat treatment is 550 °C and the time is 300 min.

[0015] Further, the soluble cerium salt is Ce(NO3)3·6H2O (cerium nitrate hexahydrate).

[0016] Further, the calcination temperature is 500 - 600 °C, and the time is 5 - 7 h. Preferably, the calcination temperature is 550 °C and the time is 6 h.

[0017] Further, the loading amount of cerium in the single-atom catalyst for catalytic degradation of ethanethiol is 0 - 1 wt%, and the loading amount of cerium is not 0; preferably, the loading amount of cerium is 0 - 0.5 wt%, and the loading amount of cerium is not 0; more preferably, the loading amount of cerium is 0.5 wt%.

[0018] The second technical solution of the present invention:

[0019] The present invention also provides an application of the single-atom catalyst prepared according to the above method in the catalytic degradation of ethanethiol.

[0020] The third technical solution of the present invention:

[0021] The present invention also provides a method for degrading ethanethiol, using the single-atom catalyst prepared according to the above method as a catalyst, including the following steps: passing ethanethiol into a device containing the single-atom catalyst and heating.

[0022] In the method for degrading ethanethiol of the present invention, 2500 - 5000 ppm of ethanethiol requires 0.2 - 1.0 g of the single-atom catalyst, and the particle size of the single-atom catalyst is 40 - 60 mesh.

[0023] In the method for degrading ethanethiol of the present invention, the heating temperature is 290 - 390 °C.

[0024] When using the single-atom catalyst of the present invention to degrade ethanethiol, it only needs to pass ethanethiol into a device containing the above single-atom catalyst and heat under normal pressure to achieve complete degradation of ethanethiol.

[0025] Compared with the prior art, the present invention has the following advantages and technical effects:

[0026] (1) The single-atom catalyst of the present invention has extremely high activity: Compared with traditional MCM-41 type and H-ZSM-5 type molecular sieve catalysts, the single-atom catalyst prepared in the present invention can achieve a conversion rate of ethanethiol of 96.26% at 350 °C. The FAU-type topological structure HY molecular sieve used in the present invention is different from other molecular sieve materials. By the dynamic confinement effect of the faujasite cage and different cerium loadings, the size of cerium metal is regulated to prepare a single-atom catalyst. The synergistic interaction between cerium atoms and their surrounding interfaces can enhance the degradation efficiency of the catalyst for ethanethiol; at the same time, the unsaturated coordination environment of the single-atom catalyst endows it with higher activity than traditional catalysts. Cerium metal atoms are evenly dispersed on the HY molecular sieve support, and 100% of the atoms participate in the catalytic reaction, thereby increasing the conversion rate of ethanethiol, which is much higher than the conversion rate of 60-70% (400 °C) of traditional MCM-41 type and H-ZSM-5 type molecular sieve catalysts.

[0027] (2) The single-atom catalyst of the present invention has an extremely long lifespan: The single-atom catalyst prepared in the present invention exhibits excellent performance in the anti-sulfur stability experiment. It can degrade C2H5SH and maintain the conversion rate of C2H5SH above 99.9% for up to 88 h. The single-atom catalyst gives full play to the advantage of 100% utilization rate of cerium atoms, and the doping of cerium greatly increases the acid site density and improves the adsorption, activation and degradation ability of the catalyst for ethanethiol. During the performance test, CO2 and H2O are introduced simultaneously. After the conversion rate of the catalyst for C2H5SH decreases, H2O and CO2 are turned off, and the conversion rate of the catalyst can recover to 100%. This shows that the influence of carbon dioxide and water vapor on the cerium-modified HY molecular sieve catalyst is reversible. The reason is that the B acid sites on the single-atom catalyst are easily shielded by OH- in the water component, and there is competitive adsorption between CO2 and ethanethiol, resulting in a decrease in the adsorption and activation ability of the B acid active sites for ethanethiol. It is proved that the single-atom catalyst not only has excellent anti-sulfur, anti-carbon and anti-water abilities, but also has the ability to flexibly respond to real complex fluctuating environments.

[0028] (3) The single-atom catalyst of the present invention exhibits excellent anti-sulfur, anti-carbon and anti-water stability and activity, and has practical application prospects. Description of the Drawings

[0029] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0030] Figure 1 It is the activity temperature diagram of the catalysts prepared in Example 1 and Comparative Examples 1-3 for the catalytic decomposition of C2H5SH;

[0031] Figure 2Ce loading dependence diagram of catalysts prepared in Example 1 and Comparative Examples 1-3 for C2H5SH degradation;

[0032] Figure 3 Fourier transform X-ray absorption fine structure diagram at the Ce l3 edge of the catalysts prepared in Example 1 and Comparative Example 3;

[0033] Figure 4 Sulfur resistance stability performance test diagram of catalysts prepared in Example 1 and Comparative Examples 1-3;

[0034] Figure 5 Water and carbon dioxide resistance performance diagram of the catalyst prepared in Example 1;

[0035] Figure 6 Water and carbon dioxide resistance performance diagram of the catalyst prepared in Comparative Example 3. Detailed implementation manners

[0036] Now, various exemplary implementation manners of the present invention will be described in detail. This detailed description should not be considered as a limitation to the present invention, but rather as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention.

[0037] It should be understood that the terms described in the present invention are only for describing specific implementation manners and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0038] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0039] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific implementation manners of the present invention specification, which are obvious to those skilled in the art. Other implementation manners obtained from the present invention specification are obvious to those skilled in the art. The present invention specification and examples are only exemplary.

[0040] The terms "comprising", "including", "having", "containing", etc. used in this text are all open-ended terms, meaning including but not limited to.

[0041] An embodiment of the present invention provides a method for preparing a single-atom catalyst for catalytic degradation of ethanethiol, comprising the following steps:

[0042] Heat-treat HY zeolite to obtain a HY zeolite support;

[0043] Immerse the HY zeolite support in an aqueous solution containing a soluble cerium salt, stir, dry and then calcine to obtain a single-atom catalyst for catalytic degradation of ethanethiol, and the loading amount of cerium in the single-atom catalyst for catalytic degradation of ethanethiol is < 2 wt%.

[0044] HY zeolite has a FAU-type topological structure. The present invention uses the equal-volume impregnation method to prepare a single-atom catalyst. Through the constraint of the FAU-type topological structure of HY zeolite and the limitation of the cerium loading amount, atomic-level dispersion of Ce species is achieved, enabling the catalyst to exhibit atomic-level active sites, which can precisely regulate the conversion path of ethanethiol and achieve efficient degradation of ethanethiol. In the single-atom catalyst of the present invention, Ce exhibits 100% atomic exposure. At the same time, the electron transfer between cerium atoms and HY zeolite enhances the adsorption energy of ethanethiol molecules and reduces the activation energy barrier, showing excellent catalytic decomposition ability of ethanethiol. In addition, the topological confinement effect ensures the stability of the single-atom catalyst. The pore channels of HY zeolite restrict the migration of Ce atoms and inhibit the aggregation of Ce metal, enabling the single-atom catalyst to exhibit good anti-sintering ability, while slowing down the sulfur poisoning and carbon deposition rates. In short, the single-atom catalyst of the present invention has excellent anti-sulfur poisoning and carbon deposition characteristics.

[0045] In the embodiment of the present invention, the heat treatment temperature is 500 - 600 °C, the time is 250 - 350 min, preferably the heat treatment temperature is 550 °C, the time is 300 min, and the heating rate is 5 °C / min.

[0046] In the embodiment of the present invention, the soluble cerium salt is Ce(NO3)3·6H2O (cerium nitrate hexahydrate).

[0047] In the embodiment of the present invention, the calcination temperature is 500 - 600 °C, the time is 5 - 7 h, preferably the calcination temperature is 550 °C, the time is 6 h, and the heating rate is 2 °C / min.

[0048] In the embodiment of the present invention, ultrasonic treatment is carried out after stirring. Preferably, the stirring time is 10 - 30 min, the ultrasonic time is 20 min, and the mechanical vibration of ultrasonic waves can accelerate the entry of the impregnation solution into the micropores of the zeolite, ensuring uniform loading of the active components inside the support.

[0049] In the embodiments of the present invention, the drying temperature is 50 - 120 °C and the time is 1 - 14 h.

[0050] In the embodiments of the present invention, the loading amount of cerium in the single-atom catalyst for catalytic degradation of ethanethiol is 0 - 1 wt%, and the loading amount of cerium is not 0; preferably, the loading amount of cerium is 0 - 0.5 wt%, and the loading amount of cerium is not 0; more preferably, the loading amount of cerium is 0.5 wt%.

[0051] The embodiments of the present invention also provide the application of the single-atom catalyst prepared according to the above method in the catalytic degradation of ethanethiol.

[0052] The embodiments of the present invention also provide a method for degrading ethanethiol. Using the single-atom catalyst prepared according to the above method as the catalyst, the method includes the following steps: introducing ethanethiol into a device containing the single-atom catalyst and heating at atmospheric pressure (290 - 390 °C). For 2500 - 5000 ppm of ethanethiol, 0.2 - 1.0 g of the single-atom catalyst is required, and the particle size of the single-atom catalyst is 40 - 60 mesh.

[0053] When using the single-atom catalyst of the present invention to degrade ethanethiol, it only needs to introduce ethanethiol into a device containing the above catalyst and heat at atmospheric pressure to achieve the complete degradation of ethanethiol.

[0054] In the present invention, metal cerium is loaded on HY zeolite, and a single-atom catalyst is prepared after calcination. The catalyst of the present invention has a unique structure. The faujasite cages of the FAU-type topological structure HY zeolite achieve atomic-level dispersion of cerium species through dynamic confinement, and metal cerium is dispersed on the HY zeolite in the form of atoms to form a single-atom catalyst. The interaction between cerium atoms and the HY zeolite enables the prepared cerium-modified HY zeolite catalyst to have a high atomic utilization rate and unique active sites, providing excellent catalytic ability. Since cerium metal atoms are uniformly dispersed on the carrier, 100% of the atoms participate in the catalytic reaction, thus having the maximum efficiency. At the same time, it can also reduce the cost of preparing the catalyst, realize the degradation of sulfur-containing volatile pollutant ethanethiol, and has good application prospects.

[0055] In the following examples and comparative examples of the present invention, the calculation method for the conversion rate of C2H5SH is as follows:

[0056] Unless otherwise specified, the room temperature in the examples and comparative examples of the present invention is calculated as 25 ± 2 °C.

[0057] Unless otherwise specified, in the examples and comparative examples of the present invention, "%" refers to mass percentage except for the conversion rate of C2H5SH.

[0058] Atmospheric pressure refers to the pressure state under standard atmospheric pressure. Unless otherwise specified, the atmospheric pressure in the examples and comparative examples of the present invention is expressed as 1 atmosphere (atm) or 101.325 kPa.

[0059] All raw materials used in the examples of the present invention are obtained by purchasing commercially. As an example, HY zeolite [n(SiO2) / n(Al2O3) = 35] (i.e., the silica-alumina ratio of HY zeolite is 35) is purchased from Zhuoran Environmental Protection Technology (Dalian) Co., Ltd.

[0060] It should be noted that the parts not described in detail in the present invention are all conventional operation means in the art and are not the focus of the present invention.

[0061] The technical solution of the present invention is further described below through examples.

[0062] Example 1

[0063] This example provides a preparation method of a single-atom catalyst for catalytic degradation of ethanethiol, and the steps are as follows:

[0064] (1) Heat-treat HY zeolite [n(SiO2) / n(Al2O3) = 35] in a muffle furnace at 550 °C for 300 min with a heating rate of 5 °C / min to obtain a HY zeolite support;

[0065] (2) Prepare a single-atom catalyst by the equal-volume impregnation method: Dissolve 0.02535 g of Ce(NO3)3·6H2O in 1.97465 mL of deionized water, add the above HY zeolite support, and the loading amount of cerium (Ce) is 0.5% (mass fraction, the same below). After stirring well for 12 min, ultrasonicate for 20 min, and impregnate overnight at room temperature; Dry the impregnated material at 95 °C for 6 h, wait until it cools to room temperature, transfer it to a muffle furnace and calcine at 550 °C for 6 h with a heating rate of 2 °C / min, thus obtaining a single-atom catalyst for catalytic degradation of ethanethiol, denoted as 0.5% cerium-loaded HY zeolite single-atom catalyst (0.5% Ce / HY).

[0066] Effect Example 1

[0067] Screen the 0.5% cerium-loaded HY zeolite single-atom catalyst prepared in Example 1 to 40 - 60 mesh, and load it into a fixed-bed reactor with a catalyst loading mass of 0.2 g. Pass a gas of ethanethiol (C2H5SH) with a concentration of 5000 ppm into the fixed-bed reactor, control the feed mass space velocity to be 9000 mL·g -1 ·h -1 , the reaction system pressure is atmospheric pressure, and the reaction temperature is 290 - 390 °C, and conduct a catalytic activity evaluation experiment for catalytic degradation of ethanethiol.

[0068] The results are shown in Figure 1 , it can be seen that: when the reaction temperature is 350 °C, the conversion rate of ethanethiol is 90.26%; when the reaction temperature is 390 °C, the conversion rate of ethanethiol can reach 100%.

[0069] The loading amount of cerium in the single-atom catalyst prepared by the present invention is only 0.5%, which can not only catalyze the degradation of ethanethiol well, but also has good water and carbon dioxide resistance.

[0070] Example 2

[0071] This example provides a method for preparing a single-atom catalyst for catalytic degradation of ethanethiol. The specific steps are the same as those in Example 1, except that the loading amount of cerium is 1%, denoted as 1% cerium-loaded HY zeolite single-atom catalyst.

[0072] Effect Example 2

[0073] The 1% cerium-loaded HY zeolite single-atom catalyst prepared in Example 2 was screened to 40-60 mesh and loaded into a fixed-bed reactor. The loading mass of the catalyst was 0.2 g. A C2H5SH gas with a concentration of 5000 ppm was introduced into the fixed-bed reactor, and the feed mass space velocity was controlled to be 9000 mL·g -1 ·h -1 , and the reaction system pressure was atmospheric pressure. The reaction temperature was 290-390 °C, and a catalytic activity evaluation experiment for catalytic degradation of ethanethiol was carried out.

[0074] The results are shown in Figure 1 , it can be seen that: when the reaction temperature is 350 °C, the conversion rate of ethanethiol is 89.78%.

[0075] Comparative Example 1

[0076] This comparative example provides a method for preparing a cerium-free loaded HY zeolite catalyst, and the steps are as follows:

[0077] The HY zeolite [n(SiO2) / n(Al2O3) = 35] was heat-treated in a muffle furnace at 550 °C for 300 min with a heating rate of 5 °C / min to obtain a cerium-free loaded HY zeolite catalyst (0Ce / HY).

[0078] Effect Example 3

[0079] The cerium-free loaded HY zeolite catalyst prepared in Comparative Example 1 was screened to 40-60 mesh and loaded into a fixed-bed reactor. The loading mass of the catalyst was 0.2 g. A C2H5SH gas with a concentration of 5000 ppm was introduced into the fixed-bed reactor, and the feed mass space velocity was controlled to be 9000 mL·g -1 ·h -1, the pressure of the reaction system is atmospheric pressure, the reaction temperature is 290 - 390 °C, and the catalytic degradation activity evaluation experiment of ethanethiol is carried out.

[0080] The results are shown in Figure 1 , it can be seen that: when the reaction temperature reaches 350 °C, the conversion rate of ethanethiol is 70.86%. When the reaction temperature is 390 °C, the conversion rate of ethanethiol can reach 100%.

[0081] Comparative Example 2

[0082] This comparative example provides a preparation method of a 2% cerium-loaded HY zeolite cluster catalyst. The specific steps are the same as those in Example 1, except that the cerium loading is 2% (2% Ce / HY).

[0083] In this comparative example, the cerium loading is 2%, and the obtained catalyst is in a cluster state.

[0084] Effect Example 4

[0085] The 2% cerium-loaded HY zeolite cluster catalyst prepared in Comparative Example 2 was sieved to 40 - 60 mesh and filled in a fixed-bed reactor. The mass of the catalyst filling was 0.2 g. The C2H5SH gas with a concentration of 5000 ppm was introduced into the fixed-bed reactor, and the feed mass space velocity was controlled at 9000 mL·g -1 ·h -1 , the pressure of the reaction system is atmospheric pressure, the reaction temperature is 290 - 390 °C, and the catalytic degradation activity evaluation experiment of ethanethiol is carried out.

[0086] The results are shown in Figure 1 , it can be seen that: when the reaction temperature is 350 °C, the conversion rate of ethanethiol is 84.49%; when the reaction temperature is 390 °C, the conversion rate of ethanethiol can reach 100%.

[0087] Comparative Example 3

[0088] This comparative example provides a preparation method of a 15% cerium-loaded HY zeolite nanoparticle catalyst. The specific steps are the same as those in Example 1, except that the cerium loading is 15% (15% Ce / HY).

[0089] In this comparative example, the cerium loading is 15%, and the obtained catalyst is in a nanoparticle state.

[0090] The Fourier transform X-ray absorption fine structure diagrams of the catalysts prepared in Example 1 and Comparative Example 3 at the Ce L3 edge are as shown in Figure 2 It can be seen that the local coordination environment of Ce in the 0.5% Ce / HY single-atom catalyst mainly shows Ce - O bonds Moreover, there is no Ce-Ce bond, indicating that Ce exists in the form of single atoms, proving the successful preparation of the single-atom catalyst. 15% Ce / HY not only has Ce-O bonds, but also a signal of the Ce-Ce bond appears at, indicating that the existence form of Ce in 15% Ce / HY is different from that in 0.5% Ce / HY, and the existence form of Ce is nanoparticles.

[0091] Effect Example 5

[0092] The 15% cerium-loaded HY zeolite nanoparticle catalyst prepared in Comparative Example 3 was sieved to 40-60 mesh and loaded into a fixed-bed reactor. The loading mass of the catalyst was 0.2 g. A C2H5SH gas with a concentration of 5000 ppm was introduced into the fixed-bed reactor, and the feed mass space velocity was controlled to be 9000 mL·g -1 ·h -1 . The pressure of the reaction system was atmospheric pressure, and the reaction temperature was 290-390 °C. A catalytic degradation activity evaluation experiment of ethanethiol was carried out.

[0093] The results are shown in Figure 1 . It can be seen that: when the reaction temperature is 350 °C, the conversion rate of ethanethiol is 89.79%; when the reaction temperature is 390 °C, the conversion rate of ethanethiol can reach 100%.

[0094] Effect Example 6

[0095] The catalysts prepared in Example 1 and Comparative Examples 1-3 were respectively sieved to 40-60 mesh, and then loaded into a fixed-bed reactor respectively. The loading mass of the catalyst was 0.2 g. C2H5SH with a concentration of 5000 ppm was introduced into the fixed-bed reactor, and the feed mass space velocity was controlled to be 9000 mL·g -1 ·h -1 . The pressure of the reaction system was atmospheric pressure, and the reaction temperature was 450 °C. A stability test for the catalytic degradation of ethanethiol was carried out. The results are shown in Figure 4 .

[0096] It can be seen from Figure 4 that: the 0.5% cerium-loaded HY zeolite single-atom catalyst prepared in Example 1 has a complete degradation life of up to 88 h for C2H5SH. The life of the HY zeolite catalyst without cerium loading (the catalyst of Comparative Example 1) is 43 h, the life of the 2% cerium-loaded HY zeolite cluster catalyst (the catalyst of Comparative Example 2) is 27 h, and the life of the 15% cerium-loaded HY zeolite nanoparticle catalyst (the catalyst of Comparative Example 3) is 33 h. The reason why the 0.5% cerium-loaded HY zeolite single-atom catalyst shows the best stability is that the catalyst gives full play to the advantage of 100% utilization rate of Ce atoms. Compared with the catalysts with high loading amounts, the catalyst prepared in Example 1 has significant advantages in terms of stability.

[0097] Effect Example 7

[0098] The catalysts prepared in Example 1 and Comparative Example 3 were respectively sieved to 40 - 60 mesh, and then filled into a fixed - bed reactor. The filling mass of the catalyst was 0.2 g. C2H5SH with a concentration of 500 ppm, 10 vol% water vapor, and 7 vol% carbon dioxide were introduced into the fixed - bed reactor. The feed mass space velocity was controlled at 9000 mL·g -1 ·h -1 , the reaction system pressure was at atmospheric pressure, and the reaction temperature was 450 °C. The water - and carbon - dioxide - resistant performance test for catalytic degradation of ethanethiol was carried out. The test results of the water - and carbon - dioxide - resistant performance of the catalyst in Example 1 are shown in Figure 5 , and the test results of the water - and carbon - dioxide - resistant performance of the catalyst in Comparative Example 3 are shown in Figure 6 .

[0099] It can be seen from Figure 5 that after introducing water vapor and carbon dioxide, the 0.5% cerium - loaded HY zeolite single - atom catalyst prepared in Example 1 began to show signs of deactivation only after completely catalytically degrading C2H5SH for 53 h. At 80 h, the conversion rate of C2H5SH decreased to 98.68%, with no obvious deactivation. And during the test process of up to 220 hours, the conversion rate of C2H5SH by the 0.5% cerium - loaded HY zeolite single - atom catalyst prepared in Example 1 was above 80%.

[0100] It can be seen from Figure 6 that the 15% cerium - loaded HY zeolite nanoparticle catalyst prepared in Comparative Example 3 took up to 101 h to completely convert C2H5SH, and the conversion rate of C2H5SH decreased to 99.1% at 150 h. It shows that the 15% cerium - loaded HY zeolite nanoparticle catalyst has more advantages in catalytically decomposing C2H5SH under the complex conditions of multi - component reaction gas and shows stronger tolerance to water vapor and carbon dioxide among them.

[0101] Then, a switching cycle experiment of water and carbon dioxide was carried out. The specific experimental process is shown in Figure 5(Carbon dioxide and water vapor are introduced from the beginning of the catalytic reaction. After the catalyst activity decreases, carbon dioxide and water vapor are shut off. After the catalyst activity is restored, water vapor and carbon dioxide are introduced again, and then water or carbon dioxide is shut off again). As water vapor and carbon dioxide are introduced into the reaction system simultaneously again, the conversion rate of the 0.5% cerium-loaded HY zeolite single-atom catalyst prepared in Example 1 decreases to 94.17% after reacting for 12 h, and the conversion rate of the 15% cerium-loaded HY zeolite nanoparticle catalyst prepared in Comparative Example 3 decreases to 95.03%. Under the condition of shutting off water vapor and only introducing carbon dioxide, the 0.5% cerium-loaded HY zeolite single-atom catalyst recovers to 100%, and the 15% cerium-loaded HY zeolite nanoparticle catalyst recovers to 98.58%. After that, the conversion rate continues to decrease. The conversion rate of the 0.5% cerium-loaded HY zeolite single-atom catalyst only decreases to 98.34% after reacting for 48 h, and the conversion rate of the 15% cerium-loaded HY zeolite nanoparticle catalyst decreases to 86.69% after reacting for 22 h. The above results prove that the presence of carbon dioxide has a minimal impact on the 0.5% cerium-loaded HY zeolite single-atom catalyst prepared in Example 1, and a greater impact on the 15% cerium-loaded HY zeolite nanoparticle catalyst prepared in Comparative Example 3. The reason is that there are a large number of surface reactive oxygen species in the 15% cerium-loaded HY zeolite nanoparticle catalyst. The reactive oxygen species are beneficial to the formation of carbonate species from CO2 and water vapor, resulting in the conversion rate of the 15% cerium-loaded HY zeolite nanoparticle catalyst not being able to recover to 100% conversion in the subsequent single-component switching experiments of water vapor or carbon dioxide, proving the irreversible consumption of reactive oxygen species and the poisoning effect of carbonate species on the catalyst.)

[0102] As can be seen from the above examples and comparative examples of the present invention, the present invention realizes the atomic dispersion of Ce species through the topological structure constraint of HY zeolite. The 8 β-cages of HY zeolite are arranged in the pattern of a diamond crystal, where each carbon atom is replaced by a β-cage, and adjacent β-cages are connected by a six-membered ring through Si-O-Si(Al) to form an faujasite cage. Through the dynamic confinement effect of the faujasite cage and different loadings, the size of the metal can be regulated to prepare catalysts with different metal existence forms (single atoms, clusters, nanoparticles), among which the single-atom catalyst has the best catalytic activity, stability, sulfur resistance, carbon resistance, and water resistance.)

[0103] The above is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.)

Claims

1. A preparation method of a single-atom catalyst for catalytic degradation of ethanethiol, characterized in that, Using HY zeolite as a support, cerium is loaded by the incipient wetness impregnation method and calcined to obtain the single-atom catalyst for catalytic degradation of ethanethiol; wherein, the loading amount of cerium is < 2 wt%.

2. The preparation method according to claim 1, characterized in that, Before the HY zeolite is loaded with cerium, it also includes a heat treatment step.

3. The preparation method according to claim 2, characterized in that, The temperature of the heat treatment is 500 - 600 °C, and the time is 250 - 350 min.

4. The preparation method according to claim 2, wherein When loading cerium by the incipient wetness impregnation method, the HY zeolite support is immersed in an aqueous solution containing a soluble cerium salt, and the soluble cerium salt is Ce(NO3)3·6H2O.

5. The preparation method according to claim 2, characterized in that, The temperature of the calcination is 500 - 600 °C, and the time is 5 - 7 h.

6. The preparation method according to claim 2, characterized in that, In the single-atom catalyst for catalytic degradation of ethanethiol, the loading amount of cerium is 0 - 1 wt%, and the loading amount of cerium is not 0.

7. The preparation method according to claim 6, characterized in that, In the single-atom catalyst for catalytic degradation of ethanethiol, the loading amount of cerium is 0 - 0.5 wt%, and the loading amount of cerium is not 0.

8. The preparation method according to claim 7, wherein In the single-atom catalyst for catalytic degradation of ethanethiol, the loading amount of cerium is 0.5 wt%.

9. Application of the single-atom catalyst prepared by the preparation method according to any one of claims 1 - 8 in the catalytic degradation of ethanethiol.

10. A method for degrading ethyl mercaptan, characterized in that, Using the single-atom catalyst prepared by the preparation method according to any one of claims 1 - 8 as a catalyst, it includes the following steps: passing ethanethiol into a device containing the single-atom catalyst and heating.

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