Preparation method and application of a single-atom catalyst for catalytic degradation of ethanethiol

Abstract

The application discloses a monatomic catalyst preparation method and application for catalytic degradation of ethanethiol, and belongs to the technical field of organic sulfur pollutant treatment. The application realizes atomic dispersion of Ce species by limiting the FAU type topological structure of HY molecular sieve and the loading amount of cerium, so that the catalyst shows atomic active sites, the conversion path of ethanethiol can be accurately controlled, and efficient degradation of ethanethiol is realized. The topological confinement effect guarantees the stability of the monatomic catalyst, the migration of Ce atoms is restricted by the channel of the HY molecular sieve, the agglomeration of Ce metal is inhibited, the monatomic catalyst shows good sintering resistance, and the sulfur poisoning and carbon deposition rates are slowed down.

Description

Technical Field

[0001] This invention belongs to the field of organic sulfur pollutant treatment technology, and particularly relates to a method for preparing a single-atom catalyst for the catalytic degradation of ethanethiol and its application. Background Technology

[0002] Ethyl mercaptan 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. It is slightly soluble in water (approximately 1.5 g / L at 25°C), highly volatile, flammable, and explosive (flash point -18°C). It is widely found in petroleum refining, natural gas odorization processes, pesticide / pharmaceutical industries, and biomass decomposition processes in landfills and sewage treatment plants. Its environmental and health hazards are significant: even low concentrations (threshold 0.001 ppm) can cause malodorous pollution; long-term exposure can lead to headaches, respiratory damage, and central nervous system poisoning. It also participates in atmospheric photochemical reactions to generate ozone and secondary organic aerosols, exacerbating environmental pollution. Therefore, developing efficient new technologies for removing ethyl mercaptan from malodorous gases is crucial for both human health and the environment.

[0003] Currently, the main technologies for treating ethanethiol include adsorption, catalytic oxidation, catalytic decomposition, and photocatalysis. Adsorption physically adsorbs ethanethiol using activated carbon, molecular sieves, or metal-organic frameworks, but it has limitations such as low adsorption capacity (usually below 100 mg / g), difficult regeneration (requiring high-temperature desorption), and inability to treat high concentrations or continuous emissions. Photocatalysis utilizes semiconductor materials such as TiO2 and g-C3N4 to generate reactive oxygen species to degrade ethanethiol under ultraviolet / visible light excitation, but it is limited by low quantum efficiency (usually less than 10%), slow reaction rate, and the potential generation of toxic intermediates such as sulfides. Catalytic oxidation uses noble metal (such as Pt, Pd / Al2O3) or transition metal oxide (such as CuO-CeO2, Co3O4) catalysts to completely oxidize ethanethiol to CO2, H2O, and SO4 in the presence of oxygen. 2- Traditional thermocatalysis offers advantages such as thorough reaction and no secondary pollution, making it particularly suitable for treating medium- to high-concentration waste gases. However, it requires high temperatures and consumes a lot of energy. Precious metal catalysts are prone to short lifespans due to sulfur poisoning, while transition metal oxides, although low in cost, face problems such as insufficient low-temperature activity and carbon buildup leading to 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 and CO2). Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a method for preparing a single-atom catalyst for the catalytic degradation of ethanethiol and its application.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

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

[0007] This invention provides a method for preparing a single-atom catalyst for the catalytic degradation of ethanethiol. Using HY molecular sieve as a support, cerium is loaded via an equal-volume impregnation method, followed by calcination to obtain the single-atom catalyst for the catalytic degradation of ethanethiol; wherein the cerium loading is <2 wt%.

[0008] HY molecular sieves possess a FAU-type topology. This invention achieves atomic-level dispersion of Ce species through the constraint of the FAU-type topology of the HY molecular sieve and the limitation of cerium loading, enabling the catalyst to exhibit atomic-level active sites. This allows for precise control of the ethanethiol conversion pathway, achieving highly efficient degradation of ethanethiol. In the single-atom catalyst of this invention, Ce exhibits 100% atomic exposure. Simultaneously, enhanced electron transfer between cerium atoms and the HY molecular sieve enhances the adsorption energy for ethanethiol molecules, lowering the activation energy barrier and demonstrating excellent catalytic decomposition ability of ethanethiol. Furthermore, the topological confinement effect ensures the stability of the single-atom catalyst. The pores of the HY molecular sieve constrain the migration of Ce atoms, inhibiting Ce metal aggregation and giving the single-atom catalyst good anti-sintering ability. It also slows down sulfur poisoning and carbon deposition rates. In summary, the single-atom catalyst of this invention exhibits excellent resistance to sulfur poisoning and carbon deposition.

[0009] Furthermore, the HY molecular sieve is further subjected to a heat treatment step before being loaded with cerium.

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

[0011] HY molecular sieve is heat-treated to obtain HY molecular sieve support;

[0012] The HY molecular sieve support is immersed in an aqueous solution containing soluble cerium salt, stirred, dried, and then calcined to obtain the single-atom catalyst for catalytic degradation of ethanethiol, wherein the cerium loading in the single-atom catalyst for catalytic degradation of ethanethiol is <2wt%.

[0013] For example, the silicon-to-aluminum ratio of HY molecular sieve is 35, that is, n(SiO2) / n(Al2O3) = 35.

[0014] Furthermore, the heat treatment temperature is 500–600°C and the time is 250–350 min, preferably the heat treatment temperature is 550°C and the time is 300 min.

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

[0016] Furthermore, the calcination temperature is 500–600°C and the time is 5–7 hours, preferably 550°C and 6 hours.

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

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

[0019] The present invention also provides the 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 a single-atom catalyst prepared according to the above method as a catalyst, comprising 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, 0.2-1.0 g of single-atom catalyst is required for 2500-5000 ppm of ethanethiol, 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] The degradation of ethanethiol using the single-atom catalyst of this invention only requires passing the ethanethiol into a device containing the aforementioned single-atom catalyst and heating it under normal pressure to achieve complete degradation of the ethanethiol.

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

[0026] (1) The single-atom catalyst of this invention exhibits extremely high activity: Compared with traditional MCM-41 and H-ZSM-5 molecular sieve catalysts, the single-atom catalyst prepared in this invention can achieve a conversion rate of 96.26% for ethanethiol at 350℃. The FAU-type topological structure HY molecular sieve used in this invention differs from other molecular sieve materials. By controlling the size of cerium metal through the dynamic confinement effect of the octahedral zeolite cage and varying the cerium loading, a single-atom catalyst is prepared. The synergistic interaction between cerium atoms and their interface enhances the catalyst's degradation efficiency for ethanethiol. Simultaneously, the unsaturated coordination environment of the single-atom catalyst endows it with higher activity than traditional catalysts. Cerium metal atoms are uniformly dispersed on the HY molecular sieve support, with 100% of the atoms participating in the catalytic reaction, thereby increasing the conversion rate of ethanethiol, which is far higher than the 60-70% (400℃) conversion rate of traditional MCM-41 and H-ZSM-5 molecular sieve catalysts.

[0027] (2) The single-atom catalyst of this invention has an ultra-long lifespan: The single-atom catalyst prepared in this invention exhibits excellent performance in sulfur resistance stability experiments. It can degrade C2H5SH and maintain the C2H5SH conversion rate above 99.9% for up to 88 hours. The single-atom catalyst leverages the advantage of 100% utilization of cerium atoms, and the cerium doping greatly increases the acid site density, improving the catalyst's adsorption, activation, and degradation ability for ethanethiol. In performance testing, when CO2 and H2O were introduced simultaneously, the catalyst's conversion rate for C2H5SH decreased. After H2O and CO2 were turned off, the catalyst's conversion rate recovered to 100%, indicating that the effects of carbon dioxide and water vapor on the cerium-modified HY molecular sieve catalyst are reversible. This is because the Brønsted acid sites on the single-atom catalyst are easily shielded by OH- in the water component, and CO2 and ethanethiol compete for adsorption, leading to a decrease in the adsorption and activation ability of the Brønsted acid active sites for ethanethiol. This demonstrates that the single-atom catalyst not only possesses excellent resistance to sulfur, carbon, and water, but also has the ability to flexibly cope with real and complex fluctuating environments.

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

[0029] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0030] Figure 1 The activity temperature diagrams for the catalytic decomposition of C2H5SH by the catalysts prepared in Example 1 and Comparative Examples 1 to 3 are shown.

[0031] Figure 2The graph shows the Ce loading dependence of the catalysts prepared in Example 1 and Comparative Examples 1 to 3 on the degradation of C2H5SH.

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

[0033] Figure 4 The graphs show the sulfur resistance stability test results of the catalysts prepared in Example 1 and Comparative Examples 1 to 3.

[0034] Figure 5 The graph shows the water and carbon dioxide resistance properties of the catalyst prepared in Example 1.

[0035] Figure 6 The figure shows the water and carbon dioxide resistance of the catalyst prepared in Comparative Example 3. Detailed Implementation

[0036] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0037] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0038] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0039] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0040] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

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

[0042] HY molecular sieve is heat-treated to obtain HY molecular sieve support;

[0043] The HY molecular sieve support was immersed in an aqueous solution containing soluble cerium salt, stirred, dried, and then calcined to obtain a single-atom catalyst for the catalytic degradation of ethanethiol. The cerium loading in the single-atom catalyst for the catalytic degradation of ethanethiol was <2 wt%.

[0044] HY molecular sieves possess a FAU-type topology. This invention employs an equal-volume impregnation method to prepare single-atom catalysts. The FAU-type topology of the HY molecular sieve, along with the limitation of cerium loading, achieves atomic-level dispersion of Ce species, resulting in atomic-level active sites on the catalyst. This allows for precise control of the ethanethiol conversion pathway, achieving highly efficient degradation of ethanethiol. In the single-atom catalyst of this invention, Ce exhibits 100% atomic exposure. Simultaneously, enhanced electron transfer between cerium atoms and the HY molecular sieve enhances the adsorption energy for ethanethiol molecules, lowering the activation energy barrier and demonstrating excellent catalytic decomposition ability of ethanethiol. Furthermore, the topological confinement effect ensures the stability of the single-atom catalyst. The pores of the HY molecular sieve constrain the migration of Ce atoms, inhibiting Ce metal aggregation and giving the single-atom catalyst good anti-sintering ability. It also slows down sulfur poisoning and carbon deposition rates. In summary, the single-atom catalyst of this invention possesses excellent resistance to sulfur poisoning and carbon deposition.

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

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

[0047] In embodiments of the present invention, 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, and the heating rate is 2°C / min.

[0048] In an embodiment of the present invention, ultrasonication is performed after stirring. The stirring time is preferably 10 to 30 minutes and the ultrasonication time is 20 minutes. The mechanical vibration of the ultrasonic waves can accelerate the entry of the impregnation liquid into the micropores of the molecular sieve, ensuring that the active components are uniformly loaded inside the carrier.

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

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

[0051] 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 a single-atom catalyst prepared according to the above method as the catalyst, comprising the following steps: passing ethanethiol into a device containing a single-atom catalyst and heating it at atmospheric pressure (290-390°C); 0.2-1.0 g of single-atom catalyst is required for 2500-5000 ppm ethanethiol; the particle size of the single-atom catalyst is 40-60 mesh.

[0053] The degradation of ethanethiol using the single-atom catalyst of this invention only requires passing the ethanethiol into a device containing the catalyst and heating it under normal pressure to achieve complete degradation of the ethanethiol.

[0054] This invention involves loading metallic cerium onto a HY molecular sieve and preparing a single-atom catalyst after calcination. The catalyst possesses a unique structure; the octahedral zeolite cages of the FAU-type topology HY molecular sieve achieve atomic-level dispersion of cerium species through dynamic confinement, dispersing metallic cerium in atomic form on the HY molecular sieve to form a single-atom catalyst. The interaction between cerium atoms and the HY molecular sieve gives the prepared cerium-modified HY molecular sieve catalyst high atomic utilization and unique active sites, providing excellent catalytic activity. Because the cerium metal atoms are uniformly dispersed on the support, 100% of the atoms participate in the catalytic reaction, resulting in maximum efficiency. Simultaneously, it can reduce the cost of catalyst preparation and achieve the degradation of sulfur-containing volatile pollutant ethanethiol, showing promising application prospects.

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

[0056] Unless otherwise specified, the room temperature in the embodiments and comparative examples of this invention is 25±2℃.

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

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

[0059] All raw materials used in the embodiments of this invention were purchased commercially. As an example, HY molecular sieve [n(SiO2) / n(Al2O3)=35] (i.e., the silicon-to-aluminum ratio of HY molecular sieve is 35) was purchased from Zhuoran Environmental Protection Technology (Dalian) Co., Ltd.

[0060] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0061] The technical solution of the present invention will be further illustrated by the following embodiments.

[0062] Example 1

[0063] This embodiment provides a method for preparing a single-atom catalyst for the catalytic degradation of ethanethiol, the steps of which are as follows:

[0064] (1) HY molecular sieve [n(SiO2) / n(Al2O3)=35] was heat-treated in a muffle furnace at 550℃ for 300 min with a heating rate of 5℃ / min to obtain HY molecular sieve support;

[0065] (2) Single-atom catalyst prepared by equal volume impregnation method: 0.02535g Ce(NO3)3·6H2O was dissolved in 1.97465mL of deionized water, and the above-mentioned HY molecular sieve support was added. The loading of cerium (Ce) was 0.5% (mass fraction, the same below). After stirring thoroughly for 12min, it was sonicated for 20min and impregnated overnight at room temperature. The impregnated material was dried at 95℃ for 6h, cooled to room temperature, and then calcined in a muffle furnace at 550℃ for 6h with a heating rate of 2℃ / min. The single-atom catalyst for catalytic degradation of ethanethiol was obtained and was denoted as 0.5% cerium-supported HY molecular sieve single-atom catalyst (0.5% Ce / HY).

[0066] Example 1

[0067] The 0.5% cerium-supported HY molecular sieve single-atom catalyst prepared in Example 1 was sieved to 40-60 mesh and packed into a fixed-bed reactor. The catalyst loading mass was 0.2 g. Ethyl mercaptan (C2H5SH) gas with a concentration of 5000 ppm was introduced into the fixed-bed reactor, and the feed mass hourly space velocity was controlled at 9000 mL·g. -1 ·h -1 The reaction system was kept at atmospheric pressure and the reaction temperature was 290–390 °C. The catalytic activity of the catalyst for the degradation of ethanethiol was evaluated.

[0068] See results Figure 1 It can be seen that when the reaction temperature is 350℃, the conversion rate of ethanethiol is 90.26%; when the reaction temperature is 390℃, the conversion rate of ethanethiol can reach 100%.

[0069] The single-atom catalyst prepared by this invention has a cerium loading of only 0.5%, which not only catalyzes the degradation of ethanethiol well, but also has good water and carbon dioxide resistance.

[0070] Example 2

[0071] This embodiment provides a method for preparing a single-atom catalyst for the catalytic degradation of ethanethiol. The specific steps are the same as in Example 1, except that the cerium loading is 1%, which is referred to as a 1% cerium-supported HY molecular sieve single-atom catalyst.

[0072] Example 2

[0073] The 1% cerium-supported HY molecular sieve single-atom catalyst prepared in Example 2 was sieved to 40-60 mesh and packed into a fixed-bed reactor. The catalyst loading mass was 0.2 g. C2H5SH gas with a concentration of 5000 ppm was introduced into the fixed-bed reactor, and the feed mass hourly space velocity was controlled at 9000 mL·g. -1 ·h -1 The reaction system was kept at atmospheric pressure and the reaction temperature was 290–390 °C. The catalytic activity of the catalyst for the degradation of ethanethiol was evaluated.

[0074] See results Figure 1 It can be seen that when the reaction temperature is 350℃, the conversion rate of ethanethiol is 89.78%.

[0075] Comparative Example 1

[0076] This comparative example provides a method for preparing a cerium-free supported HY molecular sieve catalyst, the steps of which are as follows:

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

[0078] Example 3

[0079] The cerium-free supported HY molecular sieve catalyst prepared in Comparative Example 1 was sieved to 40–60 mesh and packed into a fixed-bed reactor. The catalyst loading mass was 0.2 g. C2H5SH gas with a concentration of 5000 ppm was introduced into the fixed-bed reactor, and the feed mass hourly space velocity was controlled at 9000 mL·g. -1 ·h -1The reaction system was kept at atmospheric pressure and the reaction temperature was 290–390 °C. The catalytic activity of the catalyst for the degradation of ethanethiol was evaluated.

[0080] See results Figure 1 It can be seen that when the reaction temperature reaches 350℃, the conversion rate of ethanethiol is 70.86%. When the reaction temperature is 390℃, the conversion rate of ethanethiol can reach 100%.

[0081] Comparative Example 2

[0082] This comparative example provides a method for preparing a 2% cerium-supported HY molecular sieve cluster catalyst. The specific steps are the same as in Example 1, except that the cerium loading is 2% (2% Ce / HY).

[0083] In this comparative example, the cerium loading was 2%, and the resulting catalyst was in a clustered state.

[0084] Example of effect 4

[0085] The 2% cerium-supported HY molecular sieve cluster catalyst prepared in Comparative Example 2 was sieved to 40-60 mesh and packed into a fixed-bed reactor. The catalyst loading mass was 0.2 g. C2H5SH gas with a concentration of 5000 ppm was introduced into the fixed-bed reactor, and the feed mass hourly space velocity was controlled at 9000 mL·g. -1 ·h -1 The reaction system was kept at atmospheric pressure and the reaction temperature was 290–390 °C. The catalytic activity of the catalyst for the degradation of ethanethiol was evaluated.

[0086] See results Figure 1 It can be seen that when the reaction temperature is 350℃, the conversion rate of ethanethiol is 84.49%; when the reaction temperature is 390℃, the conversion rate of ethanethiol can reach 100%.

[0087] Comparative Example 3

[0088] This comparative example provides a method for preparing a 15% cerium-supported HY molecular sieve nanoparticle catalyst. The specific steps are the same as in Example 1, except that the cerium loading is 15% (15% Ce / HY).

[0089] In this comparative example, the cerium loading was 15%, and the resulting catalyst was in nanoparticle form.

[0090] The fine structure diagrams of the catalysts prepared in Example 1 and Comparative Example 3 at the Ce l3 edge using Fourier transform X-ray absorption are shown below. Figure 2 As shown, the local coordination environment of Ce in the 0.5% Ce / HY single-atom catalyst is mainly characterized by Ce-O bonds. Furthermore, the absence of Ce-Ce bonds indicates that Ce exists in single-atom form, proving the successful preparation of the single-atom catalyst. The 15% Ce / HY not only contains Ce-O bonds, but also... The presence of Ce-Ce bond signals indicates that Ce exists in a different form than Ce in 15% Ce / HY compared to 0.5% Ce / HY, and that Ce exists in the form of nanoparticles.

[0091] Example 5

[0092] The 15% cerium-supported HY molecular sieve nanoparticle catalyst prepared in Comparative Example 3 was sieved to 40-60 mesh and packed into a fixed-bed reactor. The catalyst loading mass was 0.2 g. C2H5SH gas with a concentration of 5000 ppm was introduced into the fixed-bed reactor, and the feed mass hourly space velocity was controlled at 9000 mL·g. -1 ·h -1 The reaction system was kept at atmospheric pressure and the reaction temperature was 290–390 °C. The catalytic activity of the catalyst for the degradation of ethanethiol was evaluated.

[0093] See results Figure 1 It can be seen that when the reaction temperature is 350℃, the conversion rate of ethanethiol is 89.79%; when the reaction temperature is 390℃, the conversion rate of ethanethiol can reach 100%.

[0094] Example 6

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

[0096] Depend on Figure 4 It can be seen that the 0.5% cerium-supported HY molecular sieve single-atom catalyst prepared in Example 1 has a complete degradation lifetime of up to 88 hours for C2H5SH, while the lifetime of the cerium-free HY molecular sieve catalyst (catalyst of Comparative Example 1) is 43 hours, the lifetime of the 2% cerium-supported HY molecular sieve cluster catalyst (catalyst of Comparative Example 2) is 27 hours, and the lifetime of the 15% cerium-supported HY molecular sieve nanoparticle catalyst (catalyst of Comparative Example 3) is 33 hours. The reason why the 0.5% cerium-supported HY molecular sieve single-atom catalyst exhibits the best stability is that this catalyst fully utilizes the advantage of 100% Ce atom utilization. Compared with the high-loading catalyst, the catalyst prepared in Example 1 has a significant advantage in stability.

[0097] Example 7

[0098] The catalysts prepared in Example 1 and Comparative Example 3 were sieved to 40-60 mesh and then loaded into fixed-bed reactors, with a catalyst loading mass of 0.2 g. A concentration of 500 ppm C₂H₅SH, 10 vol% water vapor, and 7 vol% carbon dioxide were introduced into the fixed-bed reactors, with the feed mass hourly space velocity controlled at 9000 mL·g. -1 ·h -1 The reaction system was at atmospheric pressure and the reaction temperature was 450℃. The water and carbon dioxide resistance properties of the catalyst for the catalytic degradation of ethanethiol were tested. The water and carbon dioxide resistance test results of the catalyst in Example 1 are shown below. Figure 5 The test results of the water and carbon dioxide resistance of the catalyst in Comparative Example 3 are shown in [the table below]. Figure 6 .

[0099] Depend on Figure 5 It can be seen that after the introduction of water vapor and carbon dioxide, the 0.5% cerium-supported HY molecular sieve single-atom catalyst prepared in Example 1 only began to show signs of deactivation after 53 hours of complete catalytic degradation of C2H5SH. After 80 hours, the conversion rate of C2H5SH decreased to 98.68%, with no obvious deactivation. Moreover, during the test process of up to 220 hours, the conversion rate of C2H5SH by the 0.5% cerium-supported HY molecular sieve single-atom catalyst prepared in Example 1 was above 80%.

[0100] Depend on Figure 6 It can be seen that the 15% cerium-supported HY molecular sieve nanoparticle catalyst prepared in Comparative Example 3 took as long as 101 h to completely convert C2H5SH, and the C2H5SH conversion rate dropped to 99.1% at 150 h. This indicates that the 15% cerium-supported HY molecular sieve nanoparticle catalyst has a greater advantage in catalytic decomposition of C2H5SH under complex conditions of multi-component reaction gas, and exhibits stronger tolerance to water vapor and carbon dioxide in it.

[0101] Next, an experiment was conducted to switch the water and carbon dioxide in a cycle. The specific experimental procedure is detailed in [link to experiment]. Figure 5(Carbon dioxide and water vapor were introduced at the start of the catalytic reaction. After the catalyst activity decreased, the carbon dioxide and water vapor were turned off. After the catalyst activity recovered, water vapor and carbon dioxide were introduced again, and then water or carbon dioxide was turned off again.) With the simultaneous introduction of water vapor and carbon dioxide back into the reaction system, the conversion rate of the 0.5% cerium-supported HY molecular sieve single-atom catalyst prepared in Example 1 decreased to 94.17% after 12 hours of reaction, and the conversion rate of the 15% cerium-supported HY molecular sieve nanoparticle catalyst prepared in Comparative Example 3 decreased to 95.03%. Under conditions where water vapor was turned off and only carbon dioxide was introduced, the conversion rate of the 0.5% cerium-supported HY molecular sieve single-atom catalyst recovered to 100%, and the conversion rate of the 15% cerium-supported HY molecular sieve nanoparticle catalyst recovered to 98.58%. Afterward, the conversion rate continued to decrease. The conversion rate of the 0.5% cerium-supported HY molecular sieve single-atom catalyst decreased to only 98.34% after 48 hours of reaction, and the conversion rate of the 15% cerium-supported HY molecular sieve nanoparticle catalyst decreased to 86.69% after 22 hours of reaction. The above results demonstrate that the presence of carbon dioxide has minimal impact on the 0.5% cerium-supported HY molecular sieve single-atom catalyst prepared in Example 1, but a significant impact on the 15% cerium-supported HY molecular sieve nanoparticle catalyst prepared in Comparative Example 3. This is because the 15% cerium-supported HY molecular sieve nanoparticle catalyst contains a large number of surface-active oxygen species. These active oxygen species facilitate the formation of carbonate species from CO2 and water vapor, resulting in the inability to restore the conversion rate of the 15% cerium-supported HY molecular sieve nanoparticle catalyst to 100% in subsequent water vapor or carbon dioxide single-component switching experiments. This proves the irreversible consumption of active oxygen species and the poisoning effect of carbonate species on the catalyst.

[0102] As can be seen from the above embodiments and comparative examples of this invention, this invention achieves atomic-level dispersion of Ce species through the topological constraint of HY molecular sieves. The HY molecular sieve has eight β-cages arranged in a diamond crystal pattern, where each carbon atom is replaced by one β-cage, and adjacent β-cages are linked by six-membered rings in a Si-O-Si(Al) configuration, forming an octahedral zeolite cage. By controlling the dynamic confinement effect of the octahedral zeolite cages and varying the loading, the size of the metal can be controlled, allowing the preparation of catalysts in different metal forms (single atom, cluster, nanoparticle). Among these, the single-atom catalyst exhibits the best catalytic activity, stability, sulfur resistance, carbon resistance, and water resistance.

[0103] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing a single-atom catalyst for the catalytic degradation of ethanethiol, characterized in that, Using HY molecular sieve as a support, cerium was loaded onto the catalyst via an equal-volume impregnation method, followed by calcination to obtain the single-atom catalyst for the catalytic degradation of ethanethiol; wherein the cerium loading was <2 wt%. The HY molecular sieve is further subjected to a heat treatment step before being loaded with cerium. The heat treatment temperature is 500~600℃, and the time is 250~350min; When loading cerium using the equal-volume impregnation method, the HY molecular sieve support is immersed in an aqueous solution containing soluble cerium salt; The calcination temperature is 500~600℃, and the time is 5~7h.

2. The preparation method according to claim 1, characterized in that, The soluble cerium salt is Ce(NO3)3•6H2O.

3. The preparation method according to claim 1, characterized in that, The single-atom catalyst used for the catalytic degradation of ethanethiol has a cerium loading of 0~1wt%, and the cerium loading is not 0.

4. The preparation method according to claim 3, characterized in that, The single-atom catalyst used for the catalytic degradation of ethanethiol has a cerium loading of 0~0.5wt%, and the cerium loading is not 0.

5. The preparation method according to claim 4, characterized in that, The single-atom catalyst used for the catalytic degradation of ethanethiol has a cerium loading of 0.5 wt%.

6. The application of a single-atom catalyst prepared by the preparation method according to any one of claims 1 to 5 in the catalytic degradation of ethanethiol.

7. A method for degrading ethanethiol, characterized in that, Using the single-atom catalyst prepared by the preparation method according to any one of claims 1 to 5 as a catalyst, the method includes the following steps: passing ethanethiol into a device containing the single-atom catalyst and heating it.

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