Methods for preparing sulfur-resistant supported catalysts through in-situ surface engineering, catalysts and applications

Abstract

This invention belongs to the field of catalysts, specifically relating to a method for preparing a sulfur-resistant supported catalyst through in-situ surface engineering, the catalyst itself, and its applications. The preparation method includes introducing an active metal precursor into the interior and outer surface of a porous support via liquid-phase deposition to obtain a supported catalyst precursor; placing the supported catalyst precursor in a sulfur-containing oxide atmosphere for in-situ interfacial chemical induction treatment; and cooling the treated catalyst in an inert gas flow to stabilize and solidify the interfacial bridging structure layer, thereby obtaining a sulfur-resistant supported catalyst. This invention constructs a stable interfacial bridging structure layer at the interface between the active metal and the support through in-situ induction treatment in a sulfur-containing atmosphere, significantly improving the catalyst's resistance to poisoning in sulfur-containing atmospheres.

Description

Technical Field

[0001] This invention belongs to the field of catalysts, specifically relating to a method for preparing a supported catalyst with sulfur resistance through in-situ surface engineering, the catalyst itself, and its application. Background Technology

[0002] In industrial applications such as petrochemicals, coal-fired flue gas purification, fine chemicals, and vehicle exhaust aftertreatment, trace amounts of sulfur oxides such as SO2 and SO3 are unavoidable in the process gas stream. These sulfur-containing species undergo strong chemical adsorption or chemical reactions with the active sites of supported catalysts, leading to irreversible occupation of the active sites or their conversion into inert sulfate species, resulting in catalyst poisoning and deactivation. SO2-induced catalyst sulfur poisoning has become one of the core bottlenecks limiting the large-scale industrial application of supported catalysts.

[0003] Existing technical strategies for addressing catalyst sulfur poisoning mainly fall into the following categories: First, by adjusting the catalyst formulation to introduce anti-sulfur additives, such as adding RuO2, CeO2, ZrO2, etc., to form alloy or composite oxide systems. These additives preferentially adsorb sulfur species or promote sulfate decomposition, thus delaying the poisoning process of active components. Second, by using hydrophobic supports or treating the support surface with hydrophobicity to reduce the adsorption affinity of polar sulfur-containing molecules on the catalyst surface. Third, by optimizing the catalyst pore structure to utilize shape-selective effects to repel larger-sized sulfur oxide molecules from contacting the active centers.

[0004] However, the above strategies generally suffer from the following shortcomings: the introduction of antisulfur additives often requires increasing the amount of precious metals or rare earth elements, significantly increasing catalyst costs; the hydrophobic treatment process for the support is complex and may affect the dispersion of active components and catalyst activity; the shape-selective effect of pore structure regulation for antisulfurization has limited effectiveness when dealing with small molecule SO2. More importantly, existing technologies mostly focus on the development of antisulfur formulations for specific catalyst systems, lacking a universal method that can be applied to different active metals and different support types, and impart antisulfur properties to ordinary supported catalysts through a simple and controllable pretreatment process.

[0005] In recent years, research on constructing functional interface structures on catalyst surfaces using the strong chemical interactions between sulfur and metals has attracted attention. Studies have shown that when Pt / Al2O3 catalysts operate in an SO2 atmosphere, SO2 reacts with the Al2O3 support to form sulfate species, hindering the migration of reaction intermediates and leading to a continuous decline in catalyst activity. Other studies have indicated that Pd species in Pd / γ-Al2O3 catalysts readily react with SOX to form stable palladium sulfate, causing permanent catalyst deactivation. These studies reveal the crucial role of the metal-support interface in the sulfur poisoning process from the perspective of sulfur poisoning mechanisms, but none have proposed a technical solution for achieving sulfur resistance modification of catalysts by utilizing the controllable chemical interactions of sulfur species at the interface. Some studies have also attempted to introduce SiO2 components into the Pt / Al2O3 system to inhibit sulfur poisoning, but this method is only applicable to specific support systems and lacks universality.

[0006] In summary, a general method for improving the sulfur resistance of supported catalysts through in-situ surface engineering needs to be proposed to solve the above problems. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing a supported catalyst with sulfur resistance through in-situ surface engineering, as well as the catalyst and its application.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for preparing a supported catalyst with sulfur resistance through in-situ surface engineering includes the following steps: S1. The porous support is pretreated to regulate the distribution of surface functional groups. Then, the active metal precursor is introduced into the pores and outer surface of the porous support by liquid phase deposition. After drying and calcination, a supported catalyst precursor with highly dispersed active components is obtained. S2. The supported catalyst precursor obtained in step S1 is placed in a sulfur oxide atmosphere for in-situ interfacial chemical induction treatment. The volume concentration of sulfur oxides in the atmosphere, the total flow rate of the atmosphere, and the treatment temperature window are controlled so that the active metal components undergo interfacial self-assembly under the action of sulfur oxide atmosphere, and an interfacial bridging structure layer with electronic state reconstruction characteristics is constructed in-situ at the interface between the active components and the support. S3. After the in-situ interfacial chemical induction treatment in step S2 is completed, the catalyst that has been induced is cooled in an inert gas flow to stabilize and solidify the interfacial bridging structure layer, thereby obtaining a supported catalyst with sulfur resistance.

[0009] The implementation process of step S1 is as follows: S1.1. The functional groups on the carrier surface are controlled by acid washing or alkaline washing. Acid washing uses HNO3 or HCl solution with a concentration of 0.5-2.0 mol / L, and alkaline washing uses NaOH or NH3·H2O solution with a concentration of 0.5-1.5 mol / L. The acid washing or alkaline washing time is 1-4 h. After washing, the carrier is rinsed with deionized water until the filtrate is neutral and dried at 100-120℃ for 4-8 h. S1.2. Prepare an active metal precursor solution, and immerse the porous carrier treated in step S1.1 in the precursor solution at a solid-liquid ratio of 1:5-1:20, and stir and immerse at a temperature of 20-60℃ for 6-24 hours; preferably, stir and immerse at a temperature of 25-40℃ for 12-20 hours. S1.3. The impregnated material is dried at 80-130℃ for 8-16h, and then heated to 350-600℃ in air at a heating rate of 1-5℃ / min, and calcined for 2-6h, preferably at 450-550℃ for 2-4h, to obtain a supported catalyst precursor with an active metal loading of 0.1-15wt%, preferably 1.0-2.1wt%.

[0010] The porous support material includes at least one of Al2O3, SiO2, TiO2, CeO2, ZrO2, and ZSM-5 molecular sieve. The porous support is calcined in air at 400-600℃ for 2-6 hours to remove surface adsorbed water and organic impurities.

[0011] The active metal precursor includes a soluble salt of at least one noble metal selected from Pt, Pd, Rh, and Ru, or a soluble salt of at least one transition metal selected from Mn, Fe, Co, Cu, Ce, and Ni, with a precursor solution concentration of 0.01-0.5 mol / L.

[0012] Preferably, the active metal comprises a synergistic combination of two or more metals. More preferably, the metal combination includes any one of Pt-Ce, Pt-Mn, Pd-Fe, Pd-Cu, Co-Ce, and Mn-Fe, and the mass ratio of the two active metals is 1:0.1-1:5, preferably 1:1.1.

[0013] The implementation process of step S2 is as follows: S2.1. The supported catalyst precursor obtained in step S1 is loaded into a fixed-bed reactor, and a mixed atmosphere containing sulfur oxides is introduced into the reactor. The sulfur oxides are SO2, SO3 or a mixture thereof. The total flow rate of the mixed atmosphere is controlled to be 20-100 mL per minute per gram of catalyst precursor. S2.2. The fixed-bed reactor is heated to a processing temperature window of 250-450℃, preferably 300-400℃, at a heating rate of 3-8℃ / min. The reactor is kept at this temperature for 1-8 hours, preferably 2-4 hours, so that the active metal components undergo interfacial migration and rearrangement at the atomic level under the induction of sulfur oxide atmosphere. The sulfur atoms form a stable interfacial metal-sulfur-support bridging structure with the active metal atoms and oxygen atoms on the support surface.

[0014] Step S2 involves a mixed atmosphere containing sulfur oxides, comprising a carrier gas and a mixture of sulfur oxides, wherein the volume concentration of sulfur oxides in the mixed atmosphere is 100-1000 cm³. 3 / m 3 The preferred size is 200-500cm. 3 / m 3 The carrier gas is at least one of N2, Ar, and He. Alternatively, the mixed atmosphere containing sulfur oxides may include a mixture of H2S and sulfur oxides, with an H2S volume concentration of 50-500 cm³. 3 / m 3 The volume ratio of sulfur oxides to H2S is controlled at 1:0.2-1:1.5.

[0015] The implementation process of step S3 is as follows: S3.1. After the constant temperature treatment in step S2 is completed, stop supplying the sulfur oxide mixed atmosphere and switch to high-purity inert protective gas flow. The inert protective gas is N2, Ar or He, and the gas flow rate is 40-120 mL per minute per gram of catalyst precursor. S3.2. Under inert protective gas flow conditions, the reactor temperature is uniformly reduced from the processing temperature window to below 80℃ at a cooling rate of 2-6℃ / min, so that the interfacial bridging structure layer formed in step S2 maintains a stable configuration during the cooling process, preventing uncontrolled oxidation or structural relaxation when exposed to air. S3.3. When the reactor temperature drops below 80°C, stop the inert protective gas flow, remove the catalyst and seal it for storage in a dry environment to obtain an anti-sulfur catalyst with an interfacial bridging structure layer.

[0016] The present invention also includes a catalyst obtained by the preparation method described above.

[0017] The present invention also includes an application of the catalyst described herein for treating a gas containing sulfur oxides.

[0018] Compared with the prior art, the beneficial effects of the present invention are: This invention constructs a stable interfacial bridging structure layer at the interface between the active metal and the support through in-situ induction treatment in a sulfur-containing atmosphere, significantly improving the catalyst's resistance to poisoning in a sulfur-containing atmosphere. This method is applicable to various active components such as noble metals and transition metals, as well as various support systems such as Al2O3, SiO2, TiO2, CeO2, and ZrO2, demonstrating broad applicability. The in-situ induction process can be directly implemented in the later stages of catalyst preparation, is simple to operate, has controllable processes, and is low in cost, making it suitable for industrial-scale applications. The interfacial bridging structure layer alters the adsorption intensity of reaction intermediates at the active sites, effectively avoiding acute poisoning caused by competitive adsorption of sulfur-containing species. Furthermore, the interfacial bridging structure can be restored through regeneration treatment after the catalyst has been in service, extending the catalyst's lifespan. Detailed Implementation

[0019] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the preferred embodiments.

[0020] I. Materials: The porous support materials used in the various embodiments and comparative examples of this invention, including Al2O3, SiO2, TiO2, CeO2, ZrO2, ZSM-5 molecular sieve, active metal precursors such as chloroplatinic acid, palladium nitrate, manganese nitrate, iron nitrate, cobalt nitrate, and cerium nitrate, inorganic acids such as HNO3 and HCl, and bases such as NaOH and NH3·H2O, and high-purity gases such as N2, Ar, He, SO2, and H2S, unless otherwise specified, are all commercially available industrial-grade or analytical-grade reagents that have not undergone further purification.

[0021] II. Process: Example 1: In this example, a supported Pt / Al2O3 catalyst with improved sulfur resistance through in-situ surface engineering was prepared according to the following process: S1. The porous support is pretreated to regulate the distribution of surface functional groups. Then, the active metal precursor is introduced into the pores and outer surface of the porous support by liquid phase deposition. After drying and calcination, a supported catalyst precursor with highly dispersed active components is obtained. Step S1.1: Select a γ-Al2O3 porous support and calcine it in air at 550℃ for 4 hours to remove surface adsorbed water and organic impurities. The calcined support is then acid-washed with a 1.0 mol / L HNO3 solution for 2 hours. After acid washing, it is rinsed with deionized water until the filtrate is neutral and dried at 110℃ for 6 hours.

[0022] Step S1.2: Prepare an aqueous solution of chloroplatinic acid precursor with a concentration of 0.05 mol / L. Immerse the γ-Al2O3 support treated in step S1.1 in the chloroplatinic acid solution at a solid-liquid ratio of 1:10 and stir for 12 h at 30°C.

[0023] Step S1.3: The impregnated material is dried at 110℃ for 12h, and then heated to 500℃ in air at a heating rate of 3℃ / min and calcined for 3h to obtain a supported catalyst precursor with a Pt loading of 1.0wt%, denoted as Cat-Pt / Al2O3-pre.

[0024] S2. The supported catalyst precursor obtained in step S1 is placed in a sulfur oxide atmosphere for in-situ interfacial chemical induction treatment. The volume concentration of sulfur oxides in the atmosphere, the total flow rate of the atmosphere, and the treatment temperature window are controlled so that the active metal components undergo interfacial self-assembly under the action of sulfur oxide atmosphere, and an interfacial bridging structure layer with electronic state reconstruction characteristics is constructed in-situ at the interface between the active components and the support. Step S2.1: The catalyst precursor Cat-Pt / Al2O3-pre obtained in step S1 is loaded into a fixed-bed reactor, and a mixed atmosphere of N2 and SO2 is introduced into the reactor. The volume concentration of SO2 in the mixed atmosphere is 500 cm³. 3 / m 3 The total flow rate of the mixed atmosphere is controlled at 50 mL per minute per gram of catalyst precursor.

[0025] Step S2.2: The fixed-bed reactor is heated to a processing temperature window of 300℃ at a heating rate of 5℃ / min, and kept at this temperature for 4 hours. This allows the Pt active components to undergo interfacial migration and rearrangement at the atomic level under the induction of SO2 atmosphere, and sulfur atoms form a stable Pt-S-Al2O3 interfacial bridging structure with Pt atoms and oxygen atoms on the support surface.

[0026] S3. After the in-situ interfacial chemical induction treatment in step S2 is completed, the catalyst that has been induced is cooled in an inert gas flow to stabilize and solidify the interfacial bridging structure layer, thereby obtaining a supported catalyst with sulfur resistance.

[0027] Step S3.1: After the isothermal treatment in step S2 is completed, stop supplying SO2 mixed atmosphere and switch to high-purity N2 protective gas flow, with a gas flow rate of 80 mL per minute per gram of catalyst precursor.

[0028] Step S3.2: Under N2 protective gas flow conditions, the reactor temperature is uniformly reduced from 300℃ to below 80℃ at a cooling rate of 4℃ / min.

[0029] Step S3.3: When the reactor temperature drops below 80°C, stop the N2 protective gas flow, remove the catalyst and seal it for storage in a dry environment to obtain an anti-sulfur catalyst with an interfacial bridging structure layer, denoted as Cat-Pt / Al2O3-IS.

[0030] Performance testing: Step S4.1: The obtained catalyst Cat-Pt / Al2O3-IS was analyzed using XPS. The binding energy spectra of Pt4f, S2p and Al2p were collected. The binding energy of Pt4f7 / 2 was shifted positively by 0.6 eV compared with the untreated catalyst, and the binding energy of S2p was located at 162.5 eV, confirming the formation of Pt-S-Al bonds.

[0031] Step S4.2: The acidic site density on the catalyst surface was tested using NH3-TPD. NH3 desorption curves were collected within the desorption temperature range of 50-600℃, and the surface acidic site density was 0.28 mmol / g. The Pt metal dispersion was determined to be 42% using CO chemical pulse adsorption.

[0032] Step S4.3: Record the electronic state characteristics and acidic potential density data of the interface bridging structure layer.

[0033] Step S5.1: The obtained catalyst Cat-Pt / Al2O3-IS is packed into a fixed-bed catalytic reactor, and simulated industrial waste gas is introduced, wherein the SO2 volume concentration is 100 cm³. 3 / m 3 CO volume concentration is 1000 cm³ 3 / m 3 The rest is air balance gas.

[0034] Step S5.2: Select a catalytic reaction operating temperature of 300℃ and a volume hourly space velocity of 30,000 h⁻¹. -1 .

[0035] Step S5.3: Run continuously for 100 hours, collecting gas samples from the reactor inlet and outlet every 10 hours. The CO conversion rate is determined by online gas chromatography. The initial CO conversion rate is 96%, and the CO conversion rate is 92% after 100 hours.

[0036] Step S5.4: Based on the standard that the initial conversion rate decrease does not exceed 10%, the sulfur resistance stability period of Cat-Pt / Al2O3-IS is greater than 100h.

[0037] Example 2: In this example, a supported Pd / CeO2 catalyst with improved sulfur resistance through in-situ surface engineering was prepared according to the following process: S1. The porous support is pretreated to regulate the distribution of surface functional groups. Then, the active metal precursor is introduced into the pores and outer surface of the porous support by liquid phase deposition. After drying and calcination, a supported catalyst precursor with highly dispersed active components is obtained. Step S1.1: Select a CeO2 porous support and calcine it at 500℃ for 3 hours in air. After calcination, the support is treated with an alkaline solution of 0.8 mol / L NaOH for 3 hours. After alkaline washing, it is washed with deionized water until the filtrate is neutral and then dried at 120℃ for 5 hours.

[0038] Step S1.2: Prepare an aqueous solution of palladium nitrate precursor with a concentration of 0.03 mol / L. Immerse the CeO2 support treated in step S1.1 in the palladium nitrate solution at a solid-liquid ratio of 1:8 and stir for 16 h at 40 °C.

[0039] Step S1.3: The impregnated material is dried at 100℃ for 14h, and then heated to 450℃ in air at a heating rate of 2℃ / min and calcined for 4h to obtain a supported catalyst precursor with a Pd loading of 2.0wt%, denoted as Cat-Pd / CeO2-pre.

[0040] S2. The supported catalyst precursor obtained in step S1 is placed in a sulfur oxide atmosphere for in-situ interfacial chemical induction treatment. The volume concentration of sulfur oxides in the atmosphere, the total flow rate of the atmosphere, and the treatment temperature window are controlled so that the active metal components undergo interfacial self-assembly under the action of sulfur oxide atmosphere, and an interfacial bridging structure layer with electronic state reconstruction characteristics is constructed in-situ at the interface between the active components and the support. Step S2.1: The catalyst precursor Cat-Pd / CeO2-pre is loaded into a fixed-bed reactor, and a mixed atmosphere of N2 and SO2 is introduced, with an SO2 volume concentration of 300 cm⁻¹. 3 / m 3 The total flow rate of the mixed atmosphere is 60 mL per minute per gram of catalyst precursor.

[0041] Step S2.2: The fixed-bed reactor is heated to 350℃ at a heating rate of 4℃ / min and kept at the temperature for 3h to form a Pd-S-CeO2 interface bridging structure.

[0042] S3. After the in-situ interfacial chemical induction treatment in step S2 is completed, the catalyst that has been induced is cooled in an inert gas flow to stabilize and solidify the interfacial bridging structure layer, thereby obtaining a supported catalyst with sulfur resistance.

[0043] Step S3.1: After the isothermal treatment is completed, switch to high-purity Ar protective gas flow at a flow rate of 60 mL per minute per gram of catalyst precursor.

[0044] Step S3.2: Under Ar protective gas flow conditions, reduce the temperature to below 80°C at a cooling rate of 3°C / min.

[0045] Step S3.3: Remove the catalyst and seal it for storage to obtain an anti-sulfur catalyst with an interfacial bridging structure layer, denoted as Cat-Pd / CeO2-IS.

[0046] Performance testing: Step S4.1: Using XPS analysis, the Pd3d5 / 2 binding energy is shifted positively by 0.4 eV compared to the untreated catalyst, and the S2p binding energy is located at 162.8 eV, confirming the formation of Pd-S-CeO2 bonds.

[0047] Step S4.2: The surface acidic site density was 0.32 mmol / g as determined by NH3-TPD test, and the Pd dispersion was 38% as determined by CO chemical pulse adsorption method.

[0048] Step S4.3: Record the electronic state characteristics and acidic potential density data of the interface bridging structure layer.

[0049] Step S5.1: Fill the catalytic reactor with Cat-Pd / CeO2-IS and introduce simulated industrial waste gas with an SO2 volume concentration of 150 cm³. 3 / m 3 The volume concentration of toluene is 500 cm³. 3 / m 3 The rest is air balance gas.

[0050] Step S5.2: Select an operating temperature of 280℃ and a volumetric hourly space velocity of 20000 h⁻¹. -1 .

[0051] Step S5.3: Run continuously for 100 hours, collect gas samples from the reactor inlet and outlet every 10 hours, and determine the toluene conversion rate by online gas chromatography. The initial conversion rate is 94%, and the conversion rate is 89% after 100 hours.

[0052] Step S5.4: Based on the standard that the initial conversion rate decrease does not exceed 10%, the sulfur resistance stability period of Cat-Pd / CeO2-IS is greater than 100h.

[0053] Example 3: In this example, a bimetallic supported Pt-Mn / Al2O3 catalyst with improved sulfur resistance through in-situ surface engineering was prepared according to the following process: S1. The porous support is pretreated to regulate the distribution of surface functional groups. Then, the active metal precursor is introduced into the pores and outer surface of the porous support by liquid phase deposition. After drying and calcination, a supported catalyst precursor with highly dispersed active components is obtained. Step S1.1: Select a γ-Al2O3 porous support and calcine it at 600℃ for 2 hours in air. After calcination, acid wash with 1.5 mol / L HNO3 solution for 1 hour, wash with deionized water until the filtrate is neutral, and dry at 100℃ for 8 hours.

[0054] Step S1.2: Prepare a mixed aqueous solution of bimetallic precursors containing chloroplatinic acid and manganese nitrate, with a chloroplatinic acid concentration of 0.04 mol / L, a manganese nitrate concentration of 0.08 mol / L, and a Pt to Mn molar ratio of 1:2. Immerse the γ-Al₂O₃ support treated in Step S1.1 in the bimetallic precursor mixed solution at a solid-liquid ratio of 1:15, and stir and impregnate at 25°C for 20 h.

[0055] Step S1.3: The impregnated material is dried at 120℃ for 10h, and then heated to 550℃ in air at a heating rate of 4℃ / min and calcined for 2h to obtain a supported catalyst precursor with Pt loading of 1.0wt% and Mn loading of 1.1wt%, denoted as Cat-PtMn / Al2O3-pre.

[0056] S2. The supported catalyst precursor obtained in step S1 is placed in a sulfur oxide atmosphere for in-situ interfacial chemical induction treatment. The volume concentration of sulfur oxides in the atmosphere, the total flow rate of the atmosphere, and the treatment temperature window are controlled so that the active metal components undergo interfacial self-assembly under the action of sulfur oxide atmosphere, and an interfacial bridging structure layer with electronic state reconstruction characteristics is constructed in-situ at the interface between the active components and the support. Step S2.1: Cat-PtMn / Al2O3-pre is loaded into a fixed-bed reactor, and a mixed atmosphere of N2 and SO2 is introduced, with an SO2 volume concentration of 200 cm³. 3 / m 3 The total flow rate of the mixed atmosphere is 40 mL per minute per gram of catalyst precursor.

[0057] Step S2.2: The fixed-bed reactor is heated to 400℃ at a heating rate of 6℃ / min and kept at the temperature for 2h to form a Pt-Mn-S-Al2O3 multi-metal synergistic interface bridging structure.

[0058] S3. After the in-situ interfacial chemical induction treatment in step S2 is completed, the catalyst that has been induced is cooled in an inert gas flow to stabilize and solidify the interfacial bridging structure layer, thereby obtaining a supported catalyst with sulfur resistance.

[0059] Step S3.1: After the isothermal treatment is completed, switch to high-purity N2 protective gas flow at a flow rate of 100 mL per minute per gram of catalyst precursor.

[0060] Step S3.2: Cool down to below 80°C at a cooling rate of 5°C / min under N2 protective airflow conditions.

[0061] Step S3.3: Remove the catalyst and seal it for storage to obtain an anti-sulfur catalyst with a multi-metal synergistic interface bridging structure layer, denoted as Cat-PtMn / Al2O3-IS.

[0062] Performance testing: Step S4.1: Using XPS analysis, the binding energy of Pt4f7 / 2 shifted positively by 0.8 eV compared to the untreated catalyst, the binding energy of Mn2p3 / 2 shifted negatively by 0.3 eV, and the binding energy of S2p was located at 162.3 eV, confirming the formation of Pt-Mn-S-Al2O3 multimetallic synergistic interfacial bonding.

[0063] Step S4.2: The surface acidic site density was 0.35 mmol / g as determined by NH3-TPD test, and the metal dispersion was 45% as determined by CO chemical pulse adsorption method.

[0064] Step S4.3: Record the electronic state characteristics and acidic potential density data of the multi-metal synergistic interface bridging structure layer.

[0065] Step S5.1: Cat-PtMn / Al2O3-IS is packed into the catalytic reactor, and simulated industrial waste gas is introduced, with an SO2 volume concentration of 200 cm⁻¹. 3 / m 3 CO volume concentration is 1000 cm³ 3 / m 3 The NO volume concentration is 500 cm⁻¹ 3 / m 3 The rest is N2 balance gas.

[0066] Step S5.2: Select an operating temperature of 350℃ and a volumetric hourly space velocity of 40,000 h⁻¹. -1 .

[0067] Step S5.3: Run continuously for 120 hours, collecting gas samples from the reactor inlet and outlet every 12 hours. The initial CO conversion rate was 98%, and the CO conversion rate was 95% after 120 hours; the initial NO conversion rate was 91%, and the NO conversion rate was 87% after 120 hours.

[0068] Step S5.4: Based on the standard that the initial conversion rate decrease does not exceed 10%, the sulfur resistance stability period of Cat-PtMn / Al2O3-IS is greater than 120h.

[0069] Comparative Example 1: In this comparative example, the in-situ interfacial chemical induction treatment in step S2 was omitted. The Cat-Pt / Al2O3-pre catalyst precursor obtained in step S1 was directly calcined in air at 300°C for 4 hours (without SO2 atmosphere), followed by inert atmosphere cooling in step S3 (cooling to below 80°C at 4°C / min under N2 protection) and performance testing in step S5. The remaining operating conditions were the same as in Example 1. The resulting catalyst was designated Cat-Pt / Al2O3-NT.

[0070] Comparative Example 2: In this comparative example, the processing temperature in step S2.2 was set to 550°C, exceeding the upper limit of the 250-450°C processing temperature window defined in this invention. The remaining operating conditions were the same as in Example 1. The resulting catalyst was designated Cat-Pt / Al2O3-HT.

[0071] Comparative Example 3: In this comparative example, the SO2 volume concentration in step S2.1 is set to 2000 cm⁻¹. 3 / m 3 The 100-1000cm range is beyond the limit specified in this invention. 3 / m 3 The upper limit of the concentration range was set, and the processing temperature in step S2.2 was 300°C. All other operating conditions were the same as in Example 1. The resulting catalyst was designated Cat-Pt / Al2O3-HS.

[0072] Table 1 summarizes the main process parameters of each embodiment and comparative example.

[0073] Table 1 Summary of Main Process Parameters for Examples and Comparative Examples

[0074]

[0075] III. Performance Testing Methods: The following methods were used to test the performance of the catalysts prepared in the various examples and comparative examples: a. Catalytic activity test (T) 50 Measurement): The CO catalytic oxidation reaction was carried out in a fixed-bed reactor (CO volume concentration 1000 cm³). 3 / m 3 (Air balance), volumetric space velocity 30000 h⁻¹ -1 The reaction gas does not contain SO2. The temperature is increased from 150℃ to 400℃ at a rate of 5℃ / min. The CO concentration is detected by online chromatography, and the CO conversion rate at each temperature is recorded. The temperature at which the conversion rate reaches 50% is recorded as T. 50 The tests were conducted in accordance with the relevant provisions for fixed-bed activity evaluation in GB / T34896 "General Rules for Testing Industrial Catalysts".

[0076] b. CO conversion rate test under sulfur-containing conditions: Simulated industrial waste gas containing SO2 (SO2 volume concentration 100 cm³) was introduced into a fixed-bed reactor. 3 / m 3 CO volume concentration 1000 cm³ 3 / m 3 (Air balance), volumetric space velocity 30000 h⁻¹ -1 The reaction temperature was 300℃, and the system was run continuously for 100 hours. The CO concentration was detected by online chromatography, and the initial CO conversion rate and the CO conversion rate after 100 hours were calculated.

[0077] c. XPS interface chemical state characterization: A monochromatic AlKα X-ray source was used to collect the binding energy spectra of the characteristic peaks of the active metal and the S2p peak at an energy of 30 eV. The formation of interfacial bridging bonds was determined based on the chemical shift of the binding energy.

[0078] d. NH3-TPD acidic potential density test: The sample was pretreated in a He atmosphere at 300℃ for 1 h, cooled to 50℃, and then NH3 was introduced until adsorption reached saturation. After removing the physically adsorbed NH3 by He purging, the temperature was increased from 50℃ to 600℃ at a rate of 10℃ / min. The NH3 desorption signal was recorded by a thermal conductivity detector, and the acidic potential density was calculated by integration. The NH3-TPD test method refers to the conventional experimental methods in the field of catalyst acidity characterization.

[0079] e. Metal dispersion test: CO pulsed chemical adsorption method was used. The sample was reduced at 300℃ for 1 h in H2 atmosphere. After He purging and cooling to room temperature, CO was pulsedly injected until adsorption saturation. The metal dispersion was calculated based on the CO adsorption amount.

[0080] Performance data for the examples and comparative examples are shown in Table 2.

[0081] Table 2 Performance data for examples and comparative examples

[0082] Note: Comparative Example 1 showed no S2p signal, while the S2p binding energies of Comparative Examples 2 and 3 were between 168.2 and 168.5 eV, classifying them as sulfate species.

[0083] IV. Analysis Conclusion: As shown in Table 2, Comparative Example 1, which was not treated with in-situ SO2, had an initial CO conversion rate of only 88% in a sulfur-containing atmosphere, which dropped to 62% after 100 hours of operation. The sulfur resistance stability period was only 35 hours, proving that the catalyst without interfacial bridging structure layer modification was rapidly deactivated under sulfur-containing conditions.

[0084] The treatment temperature of Comparative Example 2, at 550℃, exceeded the upper limit of the 250-450℃ window of this invention. The resulting catalyst had an initial CO conversion rate of only 82%, which decreased to 70% after 100 hours. XPS analysis showed that the S2p binding energy was at 168.5 eV, classifying it as a sulfate species (SO4). 2- This indicates that at excessively high temperatures, SO2 reacted with the support through sulfation rather than selective interfacial bridging, resulting in a decrease in metal dispersion to 22% and a significant deterioration in catalyst performance.

[0085] The SO2 volume concentration in Comparative Example 3 was 2000 cm³. 3 / m 3 100-1000cm beyond the scope of this invention 3 / m 3 At the upper limit of the range, the initial CO conversion rate of the catalyst was only 85%, which dropped to 67% after 100 h. XPS analysis also detected a large number of sulfate species (S2p binding energy 168.2 eV), indicating that the excessive SO2 concentration caused the active sites and support surface to be covered by sulfate, the interfacial bridging structure was masked by excessive sulfur species, and the metal dispersion dropped to 25%.

[0086] Embodiment 1 of the present invention uses 300℃ and 500cm 3 / m 3 The optimal induction conditions for SO2, and the prepared Cat-Pt / Al2O3-IS catalyst T 50 The initial CO conversion rate was only 185℃, 25℃ lower than that of Comparative Example 1 (untreated) at 210℃. Under sulfur-containing conditions, the initial CO conversion rate reached 96%, and remained at 92% after 100h, with a sulfur resistance stability period exceeding 100h, far superior to that of Comparative Example 1 at 35h. XPS characterization showed that the S2p binding energy was located at 162.5eV, exhibiting a characteristic peak of interfacial bridging sulfur (MS-support), rather than a sulfate peak (168-169eV), confirming the successful construction of the interfacial bridging structure layer.

[0087] Example 2 verified the applicability of the method of the present invention to the noble metal-reducible oxide support system using the Pd / CeO2 system. The obtained catalyst had an initial toluene conversion rate of 94% under sulfur-containing conditions and maintained 89% after 100 h.

[0088] Example 3 verified the synergistic effect of the multi-metal synergistic interface bridging strategy using a bimetallic Pt-Mn / Al2O3 system. 50 When the temperature was further reduced to 172°C, the CO conversion rate remained at 95% after 100 hours under sulfur-containing conditions, and the sulfur resistance stability period exceeded 120 hours, which was the best among the three examples. This indicates that multi-metal synergy can further enhance the stability of the interfacial bridging structure layer.

[0089] Based on the above data, it is evident that this invention, through in-situ surface engineering, constructs a stable interfacial bridging structure layer at the interface between the active metal and the support, which can significantly improve the catalytic activity and long-term stability of the supported catalyst in a sulfur-containing atmosphere. The set SO2 induction concentration is 100-1000 cm⁻¹. 3 / m 3 The processing temperature window of 250-450℃ has clear criticality and scientific basis. This method is simple to operate, has a wide range of applications, and can be extended to various active metal / carrier systems, showing promising prospects for industrial application.

[0090] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a supported catalyst with sulfur resistance through in-situ surface engineering, characterized in that, Includes the following steps: S1. The porous support is pretreated to regulate the distribution of surface functional groups. Then, the active metal precursor is introduced into the pores and outer surface of the porous support by liquid phase deposition. After drying and calcination, a supported catalyst precursor with highly dispersed active components is obtained. S2. The supported catalyst precursor obtained in step S1 is placed in a sulfur oxide atmosphere for in-situ interfacial chemical induction treatment. The volume concentration of sulfur oxides in the atmosphere, the total flow rate of the atmosphere, and the treatment temperature window are controlled so that the active metal components undergo interfacial self-assembly under the action of sulfur oxide atmosphere, and an interfacial bridging structure layer with electronic state reconstruction characteristics is constructed in-situ at the interface between the active components and the support. S3. After the in-situ interfacial chemical induction treatment in step S2 is completed, the catalyst that has been induced is cooled in an inert gas flow to stabilize and solidify the interfacial bridging structure layer, thereby obtaining a supported catalyst with sulfur resistance.

2. The preparation method according to claim 1, characterized in that, The implementation process of step S1 is as follows: S1.

1. The functional groups on the carrier surface are controlled by acid washing or alkaline washing. Acid washing uses HNO3 or HCl solution with a concentration of 0.5-2.0 mol / L, and alkaline washing uses NaOH or NH3·H2O solution with a concentration of 0.5-1.5 mol / L. The acid washing or alkaline washing time is 1-4 h. After washing, the carrier is rinsed with deionized water until the filtrate is neutral and dried at 100-120℃ for 4-8 h. S1.

2. Prepare an active metal precursor solution, and immerse the porous carrier treated in step S1.1 in the precursor solution at a solid-liquid ratio of 1:5-1:20, and stir and immerse at a temperature of 20-60℃ for 6-24 hours; preferably, stir and immerse at a temperature of 25-40℃ for 12-20 hours. S1.

3. The impregnated material is dried at 80-130℃ for 8-16h, and then heated to 350-600℃ in air at a heating rate of 1-5℃ / min, and calcined for 2-6h, preferably at 450-550℃ for 2-4h, to obtain a supported catalyst precursor with an active metal loading of 0.1-15wt%, preferably 1.0-2.1wt%.

3. The preparation method according to claim 2, characterized in that, The porous support material includes at least one of Al2O3, SiO2, TiO2, CeO2, ZrO2, and ZSM-5 molecular sieve. The porous support is calcined in air at 400-600℃ for 2-6 hours to remove surface adsorbed water and organic impurities.

4. The preparation method according to claim 2, characterized in that, The active metal precursor includes a soluble salt of at least one noble metal selected from Pt, Pd, Rh, and Ru, or a soluble salt of at least one transition metal selected from Mn, Fe, Co, Cu, Ce, and Ni, with a precursor solution concentration of 0.01-0.5 mol / L. Preferably, the active metal comprises a synergistic combination of two or more metals. More preferably, the metal combination includes any one of Pt-Ce, Pt-Mn, Pd-Fe, Pd-Cu, Co-Ce, and Mn-Fe, and the mass ratio of the two active metals is 1:0.1-1:5, preferably 1:1.

1.

5. The preparation method according to claim 1, characterized in that, The implementation process of step S2 is as follows: S2.

1. The supported catalyst precursor obtained in step S1 is loaded into a fixed-bed reactor, and a mixed atmosphere containing sulfur oxides is introduced into the reactor. The sulfur oxides are SO2, SO3 or a mixture thereof. The total flow rate of the mixed atmosphere is controlled to be 20-100 mL per minute per gram of catalyst precursor. S2.

2. The fixed-bed reactor is heated to a processing temperature window of 250-450℃, preferably 300-400℃, at a heating rate of 3-8℃ / min. The reactor is kept at this temperature for 1-8 hours, preferably 2-4 hours, so that the active metal components undergo interfacial migration and rearrangement at the atomic level under the induction of sulfur oxide atmosphere. The sulfur atoms form a stable interfacial metal-sulfur-support bridging structure with the active metal atoms and oxygen atoms on the support surface.

6. The preparation method according to claim 5, characterized in that, Step S2 involves a mixed atmosphere containing sulfur oxides, comprising a carrier gas and a mixture of sulfur oxides, wherein the volume concentration of sulfur oxides in the mixed atmosphere is 100-1000 cm³. 3 / m 3 The preferred size is 200-500cm. 3 / m 3 The carrier gas is at least one of N2, Ar, and He. Alternatively, the mixed atmosphere containing sulfur oxides may include a mixture of H2S and sulfur oxides, with an H2S volume concentration of 50-500 cm³. 3 / m 3 The volume ratio of sulfur oxides to H2S is controlled at 1:0.2-1:1.

5.

7. The preparation method according to claim 1, characterized in that, The implementation process of step S3 is as follows: S3.

1. After the constant temperature treatment in step S2 is completed, stop supplying the sulfur oxide mixed atmosphere and switch to high-purity inert protective gas flow. The inert protective gas is N2, Ar or He, and the gas flow rate is 40-120 mL per minute per gram of catalyst precursor. S3.

2. Under inert protective gas flow conditions, the reactor temperature is uniformly reduced from the processing temperature window to below 80℃ at a cooling rate of 2-6℃ / min, so that the interfacial bridging structure layer formed in step S2 maintains a stable configuration during the cooling process, preventing uncontrolled oxidation or structural relaxation when exposed to air. S3.

3. When the reactor temperature drops below 80°C, stop the inert protective gas flow, remove the catalyst and seal it for storage in a dry environment to obtain an anti-sulfur catalyst with an interfacial bridging structure layer.

8. A catalyst obtained by the preparation method according to any one of claims 1-7.

9. The application of the catalyst according to claim 8, characterized in that, It is used to process gases containing sulfur oxides.

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