A Highly Efficient Anti-Poisoning CO Oxidation Catalyst, Its Preparation Method and Application

Abstract

This invention discloses a highly efficient CO oxidation catalyst resistant to poisoning, its preparation method, and its application. The catalyst constructs a multi-component synergistic anti-sulfur system through "support modification + impregnation solution design + auxiliary agent regulation". With phosphate silane coupling agent synergistically modifying the support, a special impregnation solution containing L-aspartic acid and polyethylene glycol-polypropylene glycol block copolymer, and dysprosium oxide auxiliary agent as the core, it achieves high-efficiency oxidation at low temperature (≤180℃) while maintaining an activity retention rate of over 85% for more than 200 hours under sulfur-containing and humid conditions. Its lifespan is more than 4 times longer than that of traditional non-precious metal catalysts, and its cost is only 1 / 101 / 15 of that of precious metal catalysts. This solves the industrial bottlenecks of poor sulfur resistance, short lifespan, and high cost of existing catalysts.

Description

Technical Field

[0001] This invention belongs to the technical field of industrial waste gas purification and environmental catalytic materials, specifically relating to a highly efficient CO oxidation catalyst resistant to poisoning, its preparation method, and its application. Background Technology

[0002] Carbon monoxide (CO) is a colorless, odorless, highly toxic, flammable, and explosive gas widely found in automobile exhaust, industrial waste gas, and combustion products in confined spaces. Efficient and stable catalytic oxidation of CO to harmless carbon dioxide (CO2) is a key technological pathway to ensure environmental safety and human health. Currently, catalytic oxidation has become the mainstream method for CO elimination due to its mild reaction conditions and high conversion efficiency; its core lies in the performance of the catalyst. However, in practical applications such as automobile exhaust and industrial waste gas, the gas composition is complex, generally containing sulfide impurities such as sulfur dioxide (SO2). These sulfides easily interact with the active components of the catalyst, leading to catalyst poisoning and deactivation. This problem has become a core bottleneck restricting the large-scale industrial application of CO oxidation catalysts.

[0003] Current mainstream CO oxidation catalysts are mainly divided into two categories: noble metal-based and non-noble metal-based, but both have obvious drawbacks: While precious metal-based catalysts exhibit excellent CO oxidation activity at low temperatures, their resistance to sulfur poisoning is extremely poor. Studies have shown that in simulated exhaust gas containing 0.01% SO2, the CO conversion rate drops sharply to below 60% after less than 200 hours of continuous operation. Furthermore, the scarcity and high price of precious metals make it difficult to meet the cost control requirements of large-scale industrial deployments, thus limiting the economic feasibility of their long-term application.

[0004] Non-precious metal-based catalysts, while offering the advantage of low cost, generally suffer from high ignition temperatures (typically above 280°C) and insufficient low-temperature activity. More importantly, their sulfur resistance mechanisms are relatively simple, relying primarily on oxygen vacancies provided by rare earth oxides to adsorb or weaken sulfur species, making it difficult to effectively block the strong chemical interactions between sulfides and active sites. Under actual operating conditions containing sulfur and moisture, SO2 readily reacts with high-valence active metal ions (such as Co³⁺, Mn²⁺, and Mg²⁺). 4 (⁺) The reaction generates thermodynamically stable metal sulfides (such as CoS and MnS), causing irreversible deactivation of active sites. Simultaneously, the presence of water vapor promotes the adsorption and conversion of SO2 on the catalyst surface, further accelerating the sulfur poisoning process. Therefore, the stable operating time of such catalysts in real complex atmospheres is typically less than 50 hours, severely limiting their lifespan.

[0005] In summary, existing CO oxidation catalysts generally struggle to simultaneously achieve the four key performance indicators of "high activity at low temperatures, strong resistance to sulfur poisoning, long service life, and low cost." Particularly concerning sulfur resistance mechanisms, the lack of a multi-component synergistic design leads to rapid catalyst deactivation in sulfur-containing environments, necessitating frequent replacements. This not only significantly increases maintenance costs but also poses a risk of CO leakage due to catalytic failure, threatening safe production. Therefore, there is an urgent need to develop a low-cost catalyst with a novel "multi-component synergistic sulfur resistance" mechanism, capable of efficiently oxidizing CO at low temperatures and maintaining long-term stability in complex sulfur- and humid conditions. This would overcome current technological bottlenecks and promote the widespread application of CO catalytic oxidation technology in the industrial sector. Summary of the Invention

[0006] To overcome the key bottlenecks of existing CO oxidation catalysts in practical applications, such as weak resistance to sulfur poisoning, short service life, insufficient low-temperature activity, and high cost, this invention aims to provide a highly efficient, long-life, low-cost CO oxidation catalyst with excellent low-temperature activity. The invention also discloses its preparation method and its application in complex waste gas environments containing sulfur and moisture. This invention constructs a multi-component synergistic sulfur-resistant system based on "support modification + impregnation solution design + auxiliary agent regulation," while optimizing the interaction between the active component and the support. This ultimately achieves highly efficient CO oxidation under low-temperature conditions (≤180℃). Furthermore, it ensures that the catalyst maintains catalytic activity above 85% even after continuous operation for over 200 hours in actual industrial sulfur- and moisture-containing conditions. Its service life is more than twice that of existing non-precious metal-based catalysts, and its preparation cost is less than 1 / 10 that of precious metal-based catalysts. This effectively solves the core pain points of existing catalysts, meets the demand for long-cycle, efficient, stable, and low-cost CO oxidation and elimination in industrial scenarios, and breaks through the bottleneck restricting the industrial application of CO oxidation catalysts.

[0007] Specifically, the present invention provides a highly efficient CO oxidation catalyst resistant to poisoning, characterized in that the catalyst is composed of a support, an active component supported on the support, and an auxiliary agent, wherein the components, by mass percentage of the total catalyst, are: support 80%-90%, active component 8%-18%, and auxiliary agent 1%-5%; The carrier is a vanadium-tungsten-titanium composite oxide synergistically modified with phosphate-silane coupling agent; The active component is a Co-Ce composite oxide, wherein the molar ratio of Co to Ce is 2:1-4:1; The additive is dysprosium oxide.

[0008] In some specific embodiments of the present invention, the active component is a Co-Ce composite oxide, wherein the molar ratio of Co to Ce is 3:1; In some specific embodiments of the present invention, the optimal mass percentage of the adjuvant is 2%.

[0009] In some specific embodiments of the present invention, the preparation of the catalyst includes the following steps: loading an impregnation solution containing an active component precursor and an auxiliary agent precursor onto the support by an impregnation method, followed by drying and calcination, and then reduction to obtain the catalyst; The impregnation solution is composed of a base impregnation solution, an active component precursor, and an auxiliary agent precursor; The base impregnation solution is composed of chelating agent, dispersant and water, and contains, by mass percentage: 5%–12% chelating agent, 2%–5% dispersant and 83%–93% water.

[0010] In some specific embodiments of the present invention, the impregnation method is an equal-volume impregnation method.

[0011] In some specific embodiments of the present invention, the chelating agent is L-aspartic acid; the dispersant is a polyethylene glycol-polypropylene glycol block copolymer; the active component precursor is cobalt acetate and cerium acetate; and the auxiliary agent precursor is dysprosium acetate.

[0012] In some specific embodiments of the present invention, the preparation method of the carrier includes the following steps: vanadium-tungsten-titanium raw powder is sequentially contacted with phosphoric acid solution and γ-aminopropyltriethoxysilane for surface synergistic modification, followed by solid-liquid separation, drying and calcination to obtain the carrier; The vanadium-tungsten-titanium raw powder is composed of vanadium pentoxide, tungsten trioxide and titanium dioxide; the phosphoric acid is used to provide Lewis acid sites; the γ-aminopropyltriethoxysilane is used to provide amino functional groups and hydrophobic segments; and the specific surface area of ​​the carrier is ≥120m² / g. In some specific embodiments of the present invention, the preparation of the catalyst includes the following preparation steps: S1. Mix the chelating agent, dispersant and water, add the active component precursor and auxiliary agent precursor, adjust the pH of the system to 4.0–5.0 to obtain the impregnation solution, wherein the molar amount of the chelating agent is 1.0–2.0 times the total molar amount of the metal ions; S2. Contact the carrier with the impregnation solution so that the active component precursor and the auxiliary agent precursor are loaded onto the carrier; S3. The carrier loaded with active components and additives is dried and calcined sequentially; S4. The support obtained in step S3 is subjected to reduction and activation treatment by heating under a hydrogen-containing atmosphere to obtain the catalyst.

[0013] In some specific embodiments of the present invention, the chelating agent is L-aspartic acid, and the dispersant is a polyethylene glycol-polypropylene glycol block copolymer.

[0014] In some specific embodiments of the present invention, the molecular weight of the polyethylene glycol-polypropylene glycol block copolymer is 2000-4000.

[0015] In some specific embodiments of the present invention, the molecular weight of the polyethylene glycol-polypropylene glycol block copolymer is 3000.

[0016] In some specific embodiments of the present invention, the impregnation solution contains 3% L-aspartic acid by mass, and the dispersant, polyethylene glycol-polypropylene glycol block copolymer, contains 3% by mass.

[0017] In some specific embodiments of the present invention, the solid-liquid ratio of the carrier to the impregnation liquid in S2 is 1:5.

[0018] In some specific embodiments of the present invention, the calcination parameters in S3 are: heating at 5°C / min to 450-550°C and calcining for 3-5 hours.

[0019] In some specific embodiments of the present invention, the hydrogen-containing atmosphere in S4 is an H2 / N2 mixed atmosphere, wherein the volume fraction of H2 is 5% and the volume fraction of N2 is 95%; the heating temperature for reduction activation is 300°C and the reduction activation time is 2 hours.

[0020] In some specific embodiments of the present invention, a high density of Lewis acid sites is formed on the surface of the carrier, with a Lewis acid site density ≥ 0.3 mmol / g. The Lewis acid site density is determined by pyridine adsorption-Fourier transform infrared spectroscopy (Py-IR) (test standard: the active coating of the carrier is degassed under high vacuum at 350℃ for 2 h, saturated with pyridine adsorption at 150℃ and then the physical adsorption is removed, and the characteristic peak of Lewis acid at 1450 cm⁻¹ is detected, calculated based on Lambert-Beer law).

[0021] In some specific embodiments of the present invention, a high density of Lewis acid sites is formed on the surface of the carrier, with a Lewis acid site density ≥ 2.2 mmol / g.

[0022] In some specific embodiments of the present invention, the support is prepared by sequentially treating vanadium-tungsten-titanium raw powder with phosphoric acid and γ-aminopropyltriethoxysilane (KH550), so that phosphate groups and aminosilyl groups are simultaneously fixed on the surface of the support, and the two can enhance the interfacial stability through hydrogen bonding interaction.

[0023] This invention also provides a method for preparing a highly efficient CO oxidation catalyst resistant to poisoning, comprising the following preparation steps: Step 1. Vanadium-tungsten-titanium raw powder is sequentially contacted with phosphoric acid solution and γ-aminopropyltriethoxysilane for surface synergistic modification, followed by solid-liquid separation, drying and calcination to obtain the carrier; The vanadium-tungsten-titanium raw powder is composed of vanadium pentoxide, tungsten trioxide and titanium dioxide. Step 2. Mix and dissolve the chelating agent, dispersant and water, then add the active component precursor and auxiliary agent precursor, adjust the pH of the system to 4.0–5.0, and obtain the impregnation solution; The molar amount of the chelating agent is 1.0–2.0 times the total molar amount of the metal ions; the precursor of the active component is cobalt acetate and cerium acetate; the precursor of the auxiliary agent is dysprosium acetate. Step 3. Contact the carrier with the impregnation solution so that the active component precursor and the auxiliary agent precursor are loaded onto the carrier; Step 4. The carrier loaded with active components and additives is dried and calcined sequentially; Step 5. The support obtained in Step 4 is subjected to reduction and activation treatment by heating under a hydrogen-containing atmosphere to obtain the catalyst.

[0024] In some specific embodiments of the present invention, the specific preparation steps of step 1 are as follows: vanadium-tungsten-titanium raw powder is added to a phosphoric acid solution with a mass fraction of 5%-10%, and the solid-liquid ratio is controlled at 1:5-1:15. The mixture is then stirred and modified at 40-80°C. Subsequently, γ-aminopropyltriethoxysilane is added, and the mixture is stirred and modified again at 50-90°C. After modification, the mixture is filtered, the filter cake is dried at 120°C, and then calcined at 300-500°C for 2-5 hours to obtain the carrier. The vanadium-tungsten-titanium raw powder is composed of vanadium pentoxide, tungsten trioxide, and titanium dioxide, with a mass ratio of vanadium pentoxide, tungsten trioxide, and titanium dioxide of 1:a:b, where 5 ≤ a ≤ 10 and 60 ≤ b ≤ 100; the amount of the chelating agent added is 1-5 times the total mass of the metal ions; the mass ratio of γ-aminopropyltriethoxysilane to the vanadium-tungsten-titanium raw powder is 1:100-3:100. In some specific embodiments of the present invention, the specific preparation steps of step 1 are as follows: vanadium-tungsten-titanium raw powder is added to a phosphoric acid solution with a mass fraction of 5%-10%, the solid-liquid ratio is controlled at 1:10, and the mixture is stirred and modified at 60°C; then γ-aminopropyltriethoxysilane is added, and the mixture is stirred and modified again at 60°C; after modification, the mixture is filtered, the filter cake is dried at 120°C, and then calcined at 500°C for 3 hours to obtain the carrier; The vanadium-tungsten-titanium raw powder is composed of vanadium pentoxide, tungsten trioxide and titanium dioxide, with a mass ratio of vanadium pentoxide, tungsten trioxide and titanium dioxide of 1:5:94; the mass ratio of γ-aminopropyltriethoxysilane to the vanadium-tungsten-titanium raw powder is 1:100-3:100.

[0025] In some specific embodiments of the present invention, the mass fraction of the phosphoric acid is 8%.

[0026] In some specific embodiments of the present invention, the mass ratio of γ-aminopropyltriethoxysilane to vanadium-tungsten-titanium raw powder is 2:100.

[0027] In some specific embodiments of the present invention, the chelating agent is L-aspartic acid, and the dispersant is a polyethylene glycol-polypropylene glycol block copolymer.

[0028] In some specific embodiments of the present invention, the molecular weight of the polyethylene glycol-polypropylene glycol block copolymer is 2000-4000.

[0029] In some specific embodiments of the present invention, the molecular weight of the polyethylene glycol-polypropylene glycol block copolymer is 3000.

[0030] In some specific embodiments of the present invention, the impregnation solution contains 3% L-aspartic acid by mass, and the dispersant, polyethylene glycol-polypropylene glycol block copolymer, contains 3% by mass.

[0031] In some specific embodiments of the present invention, the solid-liquid ratio (mass ratio) of the carrier to the impregnation liquid in step 3 is 1:2-1:7.

[0032] In some specific embodiments of the present invention, the solid-liquid ratio of the carrier to the impregnation liquid in step 3 is 1:5.

[0033] In some specific embodiments of the present invention, the calcination parameters in step 4 are: heating to 450-550℃ at 5℃ / min, calcining for 3-5 hours; the hydrogen-containing atmosphere in step 5 is a mixed atmosphere of H2 / N2, wherein the volume fraction of H2 is 1%-5% and the volume fraction of N2 is 95-99%; the heating temperature for reduction activation is 200-400℃, and the reduction activation time is 1-4 hours.

[0034] In some specific embodiments of the present invention, the calcination parameters in step 4 are: heating to 450-550℃ at 5℃ / min and calcining for 3-5 hours; the hydrogen-containing atmosphere in step 5 is a H2 / N2 mixed atmosphere, wherein the volume fraction of H2 is 5% and the volume fraction of N2 is 95%; the heating temperature for reduction activation is 300℃ and the reduction activation time is 2 hours.

[0035] In some specific embodiments of the present invention, the calcination parameters in step 4 are: heating to 500°C at 5°C / min, calcining for 4 hours, and the dispersion of the active component after reduction and activation is ≥92%.

[0036] The present invention also provides the application of any of the highly efficient anti-poisoning CO oxidation catalysts described in any one of the claims, or the catalysts prepared by any one of the preparation methods described in any one of the claims, in the catalytic oxidation of carbon monoxide.

[0037] In some specific embodiments of the present invention, the application scenario is an industrial waste gas purification process containing sulfur dioxide and water vapor, or a humid air purification process containing sulfur dioxide and water vapor.

[0038] In some specific embodiments of the present invention, the application is carbon monoxide removal in steel sintering flue gas purification, automobile cold start exhaust gas treatment, industrial furnace and kiln exhaust gas treatment, underground garage ventilation and purification, and enclosed space air purification.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows: Multi-component synergistic sulfur resistance significantly enhances poisoning resistance: A triple sulfur resistance mechanism is constructed, consisting of a "synergistic modified carrier + residual fragments in the impregnation solution + additives," resulting in a multiplied synergistic effect: ① Phosphate-silane coupling agent synergistically modifies the carrier: The Lewis acidic sites of phosphate inhibit SO2 adsorption and promote sulfide desorption through protonation, while the hydrophobic segments of KH550 reduce water vapor adsorption, preventing synergistic poisoning. Simultaneously, the stable structure formed by the amino group and the phosphate hydroxyl group strengthens the durability of the acidic sites; ② The amino fragments of residual L-aspartic acid synergistically enhance the weak hydrogen bonding ability with SO2 on the carrier surface with the amino group of KH550, preventing SO2 from reacting with Co. 3 + Ce 4+ Stable sulfides are formed, and the bound state is easily oxidized and decomposed by O2, realizing the "dynamic desorption" of sulfur species; ③ The hydrophilic segments of PPG-PEG and the hydrophobic segments of KH550 work together to accelerate water vapor desorption and further reduce the adsorption probability of sulfides; ④ Dy2O3 is dual-coordinated with the phosphate and silane amino groups of the carrier to enhance the stability of the carrier structure and acidic sites and inhibit the erosion of sulfur species.

[0040] 2. Significantly extended lifespan and excellent stability: ① The multi-component anti-sulfur mechanism avoids permanent poisoning of active sites. At the same time, the synergistic modification of the support structure by the phosphoric acid-silane coupling agent (the specific surface area decreases by only 3% after aging at 500℃ for 10h, which is far superior to the 5% of single phosphoric acid modification) and the synergistic dispersion effect of PPG-PEG and KH550 inhibit the aggregation of active components. Multiple synergies significantly extend the catalyst lifespan. Under simulated industrial conditions (CO 1%, O2 5%, SO2 0.05%, + nitrogen (balance gas), relative humidity controlled at 50% by a humidity generator (calibrated at 25℃), reaction temperature stabilized at 180℃, total gas space velocity 30000h⁻¹, total flow rate 2500mL / min), the CO conversion rate is still maintained at 92.3% after 200h of continuous operation, ≥90.2% after 250h of operation, and 85.1% after 300h of operation. This is more than 4 times longer than existing non-precious metal catalysts (lifespan <80h) and more than 20% longer than single phosphoric acid modified catalysts. 3. Excellent low-temperature activity: The proprietary impregnation solution ensures high dispersion of the Co-Ce-Dy active components. 3+ With Ce 4 ⁺ Electron transfer efficiency improved by 40%, Dy 3+ Optimize the number of oxygen vacancies to improve CO conversion at 180°C. 4. Low cost: It uses non-precious metal raw materials, and the cost of the exclusive impregnation solution components (L-aspartic acid, PPG-PEG) is lower than that of conventional systems. The overall cost is only 1 / 10 to 1 / 15 of that of Pt-based catalysts, making it suitable for large-scale industrial production. Attached Figure Description

[0041] Appendix Figure 1 These are the Py-FTIR test spectra of Examples 1-2 and Comparative Examples 1-2; Appendix Figure 2 These are the low-temperature CO conversion activity test data for Examples 1-2 and Comparative Examples 1-2; Appendix Figure 3 These are the EPR test results (oxygen vacancy related indicators) of Examples 1-2 and Comparative Examples 1-2. Appendix Figure 4 These are the sulfur resistance and lifespan test results of Examples 1-2 and Comparative Examples 1-2. Detailed Implementation

[0042] The present invention will be further described below with reference to specific embodiments. It should be understood that these embodiments are only used to illustrate the technical solutions of the present invention by way of example and do not constitute a limitation on the scope of protection of the present invention. In addition, based on reading and understanding the disclosure of the present invention, those skilled in the art can make various equivalent substitutions, modifications or improvements to the present invention. Any equivalent changes made in accordance with the spirit and substance of the present invention should be covered within the scope of protection claimed in this application.

[0043] In a first aspect, the present invention provides a highly efficient CO oxidation catalyst resistant to poisoning, comprising a support, an active component supported on the support, and an auxiliary agent, wherein the components, by mass percentage of the total catalyst, are: support 80%-90%, active component 8%-18%, and auxiliary agent 1%-5%; The specific components are as follows: (1) Carrier: Phosphoric acid-silane coupling agent synergistic modification of vanadium-tungsten-titanium composite oxide, the preparation method is as follows: vanadium-tungsten-titanium raw powder (V2O5:WO3:TiO2 mass ratio 1:5:94) is added to a 5%-10% phosphoric acid solution, the solid-liquid ratio is 1:10, and the mixture is stirred at 60℃ for 1h; then 1%-3% of the raw powder mass of γ-aminopropyltriethoxysilane (KH550) is added, and the mixture is stirred at 60℃ for another 1h, filtered, dried at 120℃ for 4h, and calcined at 500℃ for 3h; the two work synergistically. The benefits are manifested in the following ways: Phosphoric acid can form a high density of Lewis acid sites on the carrier surface, inhibiting SO2 adsorption and promoting sulfide desorption through "protonation"; the amino groups of KH550 can form stable hydrogen bonds with the hydroxyl groups of phosphoric acid, while its hydrophobic segments can reduce the adsorption and residence of water vapor on the carrier surface, avoiding the synergistic poisoning of water vapor and sulfides, and can enhance the interfacial binding force between the carrier and the active component, further improving the specific surface area (≥120m² / g) and structural stability of the carrier, laying a dual foundation for long lifespan; (2) Active component: The active component is a Co-Ce composite oxide, with a molar ratio of Co to Ce of 2:1-4:1, using cobalt acetate (Co(CH3COO)2·4H2O) and cerium acetate (Ce(CH3COO)3·xH2O) as precursors; the solid solution formed by Co-Ce can increase the number of oxygen vacancies, and Ce... 4 The ⁺ / Ce³⁺ redox cycle can rapidly repair mildly poisoned active sites; (3) Additives: The component is Dy2O3, with dysprosium acetate (Dy(CH3COO)3·4H2O) as the precursor; Dy 3+ It can simultaneously form a stable coordination structure with the phosphate group of phosphoric acid on the carrier surface and the amino group of silane coupling agent, further enhancing the sulfur resistance and structural stability of the acidic sites of the synergistically modified carrier, while inhibiting the aggregation of active components.

[0044] The aforementioned precursors of the additives and active components are loaded onto the carrier by contacting it with a dedicated anti-sulfur impregnation solution. This dedicated anti-sulfur impregnation solution consists of a chelating agent (L-aspartic acid), a dispersant (polyethylene glycol-polypropylene glycol block copolymer, PPG-PEG, molecular weight 2000-4000), and deionized water, with the following mass percentages: chelating agent 5%-12%, dispersant 2%-5%, and deionized water 83%-93%. L-aspartic acid not only forms stable chelates with metal ions, but its amino segments also synergize with the amino groups of the silane coupling agent on the carrier surface, enhancing the weak hydrogen bonding ability with SO2 and preventing strong binding between SO2 and the active component. The amphiphilic structure of PPG-PEG synergizes with the hydrophobic segments of KH550 on the carrier surface, guiding rapid desorption of water vapor and further reducing the adsorption residence time of sulfides on the catalyst surface.

[0045] Secondly, the present invention provides a method for preparing the above-mentioned catalyst, comprising the following preparation steps: (1) Vanadium-tungsten-titanium raw powder was added to a phosphoric acid solution with a mass fraction of 5%-10% and the solid-liquid ratio was controlled at 1:10. The mixture was stirred and modified at 60°C for 1 hour. Then γ-aminopropyltriethoxysilane was added and stirred and modified at 60°C for another hour. After the modification was completed, the mixture was filtered, and the filter cake was dried at 120°C for 4 hours and then calcined at 500°C for 3 hours to obtain the carrier. The vanadium-tungsten-titanium raw powder is composed of vanadium pentoxide, tungsten trioxide and titanium dioxide, with a mass ratio of vanadium pentoxide, tungsten trioxide and titanium dioxide of 1:5:94; the mass ratio of γ-aminopropyltriethoxysilane to the vanadium-tungsten-titanium raw powder is 1:100-3:100.

[0046] (2) Add the chelating agent, dispersant and water to deionized water and mix to dissolve. Then, add the active component precursor and auxiliary agent precursor, stir at 70°C for 1 hour, and adjust the pH of the system to 4.0–5.0 to obtain the impregnation solution. The molar amount of the chelating agent is 1.5 times the total molar amount of the metal ions; the precursor of the active component is cobalt acetate and cerium acetate; the precursor of the auxiliary agent is dysprosium acetate. (3) Contact the carrier with the impregnation solution and let it stand at room temperature for 12 hours, stirring once every 2 hours to ensure uniform loading of active components and additives; (4) Dry the carrier loaded with active components and additives at 120°C for 6 hours, and then calcine it in a muffle furnace at 5°C / min to 450-550°C for 3-5 hours (slow heating can retain more anti-sulfur active fragments and avoid the collapse of the carrier structure). (5) In a tube furnace under an H2 / N2 (5% / 95%) atmosphere, the support obtained in step (4) is heated for reduction and activation treatment. The reduction is carried out at 300°C for 2 hours, and the target catalyst is obtained after cooling. Example

[0047] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0048] Example 1: Preparation and performance testing of a highly efficient CO oxidation catalyst resistant to poisoning Preparation steps: (1) Pretreatment of the carrier: Take 100g of vanadium-tungsten-titanium raw powder (V2O5:WO3:TiO2=1:5:94, mass ratio), add 1000mL of 8% phosphoric acid solution (solid-liquid ratio 1:10), stir at 60℃ for 1h for modification; then add 2g of γ-aminopropyltriethoxysilane (KH550), continue stirring at 60℃ for 1h for modification, filter, dry at 120℃ for 4h, and calcine at 500℃ for 3h to obtain vanadium-tungsten-titanium carrier synergistically modified by phosphoric acid-silane coupling agent (acidic site density 2.2 mmol / g); (2) Preparation of exclusive anti-sulfur impregnation solution: ① Take 12g of L-aspartic acid and 4.5g of PPG-PEG (molecular weight 3000) and add them to 133.5mL of deionized water, stir at 60℃ for 30min to dissolve; ② Add 22.5g of cobalt acetate, 13.4g of cerium acetate (Co:Ce=3:1, molar ratio), and 2.0g of dysprosium acetate (Dy percentage 2%), stir at 70℃ for 1h, and adjust the pH to 4.5 with dilute acetic acid to obtain the impregnation solution; (3) Equal volume impregnation: Add 90g of modified carrier to the impregnation solution, let stand at room temperature for 12h, and stir once every 2h; (4) Drying and calcining: Dry at 120℃ for 6 hours, then calcin in a muffle furnace at 5℃ / min to 500℃ for 4 hours; (5) Reduction and activation: Reduce at 300℃ for 2h under H2 / N2 (5% / 95%) atmosphere, and then cool to obtain the target catalyst.

[0049] Example 2: Preparation of a highly efficient CO oxidation catalyst resistant to poisoning The difference from Example 1 is that Co:Ce = 4:1 (molar ratio), PPG-PEG molecular weight is 2000, and the rest of the steps are the same.

[0050] Comparative Example 1: Preparation of Non-Noble Metal Catalysts Al2O3 was used as a carrier, conventional citric acid was used as a chelating agent (without dispersant), and Co-Ce active components were loaded (in the same proportion as in Example 1). The preparation steps were the same as in Example 1.

[0051] Comparative Example 2: Preparation of CO oxidation catalyst with unmodified vanadium-tungsten-titanium support Unmodified vanadium-tungsten-titanium was used as the carrier, and the remaining components and steps were the same as in Example 1. Example 3: Characterization tests of different CO catalysts, including Py-FTIR. The acid properties and coordination environment of the catalyst surface were analyzed using pyridine adsorption-infrared spectroscopy (Py-FTIR). The specific steps are as follows: The catalysts of Examples 1-2 and Comparative Examples 1-2 were pretreated under vacuum at 200°C for 2 h to remove surface adsorbates. Then, pyridine vapor was introduced for adsorption for 30 min, followed by purging with N2 at 150°C to remove non-chemically adsorbed pyridine. Finally, infrared spectra were collected.

[0052] The test results are attached. Figure 1 As shown, the results indicate that characteristic absorption peaks at 1450 cm⁻¹ and 1540 cm⁻¹, respectively, are attributed to pyridine adsorbed on Lewis acid sites (L-acids) and Brønsted acid sites (B-acids), indicating that all samples simultaneously contain both types of acidic centers. Notably, the absorption intensity at 1450 cm⁻¹ in Example 1 is significantly higher than that in the comparative example, suggesting a higher density of Lewis acid sites on its surface.

[0053] By combining indirect evidence from other characterization methods, a reasonable inference can be made about the structural origin of acid enhancement: XPS analysis showed that the binding energies of the Dy, P, and N orbitals in Example 1 exhibited a systematic shift compared to the standard values, suggesting that the binding energies of Dy³⁺ and the phosphate groups (–PO) on the support are related to this shift. x There are electronic interactions between ) and silane amino (–NH2).

[0054] Example 4: Performance Testing of Different CO Catalysts The catalysts in Examples 1-2 and Comparative Examples 1-2 were tested using the same standards and procedures. Only the test data for each sample were recorded. The specific tests are as follows: (a) Low-temperature CO conversion activity test 1. Low-temperature CO conversion activity test (1) Detection steps Sample loading: Load the sample into the fixed-bed microreactor (loading volume 5mL), introduce nitrogen gas with a purity ≥99.99%, pretreat at 200℃ for 30min to remove surface impurities and physically adsorbed water; Operating conditions: Simulate sulfur-free and water-free industrial flue gas, with a gas mixture of 1 vol% CO + 5 vol% O2 + nitrogen (balance gas), a total space velocity of 30000 h⁻¹, a total flow rate of 2500 mL / min, and continuous sample passage; Activity detection: The device was stabilized at 160℃, 180℃, 200℃ and 220℃ for 30 min respectively. The inlet and outlet CO concentrations were detected by gas chromatograph (TCD detector) and the conversion rate was calculated. The fixed bed operation was kept stable throughout the process.

[0055] (2) Corresponding data results (3) The corresponding attached figure is as follows Figure 2 As shown.

[0056] 2. ERP Testing (1) Detection steps EPR tests were conducted on the catalysts of Examples 1-2 and Comparative Examples 1-2. During the test, the sample signal was detected with g-value as the abscissa, and the total spin number, concentration (mol), concentration ( / mm³), and other oxygen vacancy-related indicators of each sample were quantitatively measured. The signal response of each sample in the g-value range of 1.98~2.03 was recorded, and the quantitative data related to oxygen vacancy were statistically analyzed and compiled into a table.

[0057] (2) Corresponding data results (3) The corresponding attached figure is as follows Figure 3 As shown.

[0058] (ii) Sulfur resistance and lifespan test (1) Detection steps Sample pretreatment: The sample loading and nitrogen pretreatment steps are completely consistent with those for the low-temperature CO conversion activity test; Operating conditions: Simulate industrial sulfur-containing humid flue gas, with gas mixture of 1 vol% CO + 5 vol% O2 + 0.05 vol% SO2 + nitrogen (balance gas), relative humidity of 50% (calibrated at 25℃), constant temperature of 180℃, total space velocity of 30000 h⁻¹, total flow rate of 2500 mL / min, and continuous operation for 300 h; Stability testing: The CO concentration at the outlet was detected by gas chromatograph after continuous operation for 200h, 250h and 300h respectively, the corresponding conversion rate was calculated, and the decay trend of CO conversion rate during continuous operation of the fixed bed was recorded to ensure the stability of operating parameters throughout the process.

[0059] (2) Corresponding data results (3) The corresponding attached figure is as follows Figure 4 As shown.

[0060] (iii) Thermal stability test (including specific surface area aging test) 1. Catalytic activity and thermal stability Testing steps: ① Sample aging: The sample is aged at 500℃ in an air atmosphere for 10 hours and then naturally cooled to room temperature; ② Activity test: The aged sample is loaded into a fixed bed reactor and the CO conversion rate is measured under the low temperature activity test condition of 180℃. The CO conversion rate is compared with that of the fresh sample at 180℃ to calculate the decrease in activity. Corresponding data results: 2. Specific surface area aging test (BET method, low temperature nitrogen adsorption-desorption) Testing steps: ① Sample pretreatment: Take fresh samples and samples aged at 500℃ for 10 hours, degas at 120℃ under vacuum for 2 hours to remove surface impurities and adsorbed water; ② Testing process: Measure the nitrogen adsorption-desorption isotherm using a BET adsorption instrument and calculate the sample specific surface area; ③ Data calculation: Specific surface area decrease rate = (specific surface area of ​​fresh sample - specific surface area of ​​aged sample) / specific surface area of ​​fresh sample × 100%; Corresponding data results: Based on the Py-FTIR characterization tests in Example 3 and the low-temperature CO conversion activity, sulfur resistance lifetime, and thermal stability tests in Example 4, the following core conclusions can be drawn, covering aspects such as the catalyst's surface acidity, structural characteristics, catalytic performance, poisoning resistance, and thermal stability: 1. Surface acidity and coordination structure: All tested catalysts contained Lewis acid sites (L acid) and Brønsted acid sites (B acid), with the Lewis acid site density in Example 1 being significantly higher than that in the comparative example. In Example 1, Dy³⁺ formed dual coordination with the phosphate group and silane amino group of the support. This structure not only triggered electronic interactions and confirmed the changes in coordination-related characteristic peaks, but also stabilized the crystal phase integrity of the support and improved the thermal / chemical stability of the support.

[0061] 2. Resistance to sulfation deactivation: The dual coordination structure can effectively enrich and protect Lewis acid sites. Under simulated sulfur-containing humid conditions, the Lewis acid site retention rate of Example 1 is ≥85%, and the amount of sulfur species deposited on the surface is significantly lower than that of the comparative example, which can effectively inhibit SO2 / H2O-induced sulfation deactivation.

[0062] 3. Low-temperature CO conversion activity: The low-temperature CO conversion activities of Examples 1 and 2 are generally better than those of Comparative Examples 1 and 2, with Example 1 showing the best performance, exhibiting the highest CO conversion rate at all temperature points from 160℃ to 220℃. The oxygen vacancy-related indicators of the catalyst are positively correlated with the low-temperature CO conversion activity. The total spin number and oxygen vacancy concentration of Example 1 are the highest among all samples, indicating that the enrichment of oxygen vacancies can enhance the low-temperature CO conversion activity of the catalyst.

[0063] 4. Sulfur resistance and long-term operation capability: Under the simulated industrial flue gas conditions containing sulfur and moisture, the sulfur resistance and long-term operation stability of the examples are far superior to those of the comparative examples. Among them, Example 1 performed the best, maintaining a CO conversion rate of 85.1% even after 300 hours of continuous operation. Comparative Example 1, under the same conditions, saw its conversion rate drop significantly to 52.3% after only 80 hours of operation, failing to complete the 300-hour test. Although Comparative Example 2 could operate for 300 hours, its conversion rate was only 63.7%, and its lifespan was significantly shorter than that of Example 1.

[0064] 5. Thermal stability and structural retention capability Catalytic activity thermal stability: After aging in air at 500℃ for 10 hours, the activity of the examples decreased much less than that of the comparative examples. Example 1 showed a decrease of only 1.7 percentage points, exhibiting the best catalytic activity retention. Comparative Example 1 showed an activity decrease of 9.3 percentage points, the highest among all samples.

[0065] Specific surface area stability: The specific surface area of ​​all samples decreased after high-temperature aging, but the specific surface area decrease rate of the examples was significantly lower than that of the comparative examples. The decrease rate of Example 1 was only 3.04%, indicating that its carrier structure has a stronger ability to maintain its structure at high temperatures and has the best structural stability.

[0066] Correlation between structure and performance: The dual coordination structure of Example 1 is the core reason for its optimal overall performance. This structure not only protects and enriches Lewis acid sites by stabilizing the support skeleton and regulating the surface electronic environment, but also improves the thermal / chemical stability of the support. This results in a comprehensive improvement in low-temperature CO conversion activity, sulfur and poisoning resistance, thermal stability and long-term operation performance.

[0067] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to the technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, the above-described features have similar functions to (but are not limited to) those disclosed in this application.

Claims

1. A highly efficient CO oxidation catalyst resistant to poisoning, characterized in that, The catalyst is composed of a support, an active component supported on the support, and an additive. The components, by mass percentage of the total catalyst, are: support 80%-90%, active component 8%-18%, and additive 1%-5%. The carrier is a vanadium-tungsten-titanium composite oxide synergistically modified with phosphate-silane coupling agent; The active component is a Co-Ce composite oxide, wherein the molar ratio of Co to Ce is 2:1-4:1; The additive is dysprosium oxide.

2. The highly efficient CO oxidation catalyst resistant to poisoning as described in claim 1, characterized in that, The preparation of the catalyst includes the following steps: loading an impregnation solution containing an active component precursor and an auxiliary agent precursor onto the support using an impregnation method, followed by drying and calcination, and then reduction and activation to obtain the catalyst; The impregnation solution is composed of a base impregnation solution, an active component precursor, and an auxiliary agent precursor; The base impregnation solution is composed of a chelating agent, a dispersant, and water, and by mass percentage comprises: 5%–12% chelating agent, 2%–5% dispersant, and 83%–93% water; Preferably, the chelating agent is L-aspartic acid; the dispersant is a polyethylene glycol-polypropylene glycol block copolymer; the active component precursor is cobalt acetate and cerium acetate; and the auxiliary agent precursor is dysprosium acetate.

3. The highly efficient CO oxidation catalyst resistant to poisoning as described in any one of claims 1-2, characterized in that, The preparation method of the carrier includes the following steps: vanadium-tungsten-titanium raw powder is sequentially contacted with phosphoric acid solution and γ-aminopropyltriethoxysilane for surface synergistic modification, followed by solid-liquid separation, drying and calcination to obtain the carrier; The vanadium-tungsten-titanium raw powder is composed of vanadium pentoxide, tungsten trioxide and titanium dioxide; the phosphoric acid is used to provide Lewis acid sites; the γ-aminopropyltriethoxysilane is used to provide amino functional groups and hydrophobic segments; and the specific surface area of ​​the carrier is ≥120m² / g.

4. The highly efficient CO oxidation catalyst resistant to poisoning as described in claim 3, characterized in that, The preparation of the catalyst includes the following steps: S1. Mix the chelating agent, dispersant and water, add the active component precursor and auxiliary agent precursor, adjust the pH of the system to 4.0–5.0 to obtain the impregnation solution, wherein the molar amount of the chelating agent is 1.0–2.0 times the total molar amount of the metal ions; S2. Contact the carrier with the impregnation solution so that the active component precursor and the auxiliary agent precursor are loaded onto the carrier; S3. The carrier loaded with active components and additives is dried and calcined sequentially; S4. The support obtained in step S3 is subjected to reduction treatment by heating under a hydrogen-containing atmosphere to obtain the catalyst.

5. A method for preparing a highly efficient CO oxidation catalyst resistant to poisoning, characterized in that, The preparation steps include the following: Step 1. Vanadium-tungsten-titanium raw powder is sequentially contacted with phosphoric acid solution and γ-aminopropyltriethoxysilane for surface synergistic modification, followed by solid-liquid separation, drying and calcination to obtain the carrier; The vanadium-tungsten-titanium raw powder is composed of vanadium pentoxide, tungsten trioxide, and titanium dioxide. Step 2. Mix and dissolve the chelating agent, dispersant and water, then add the active component precursor and auxiliary agent precursor, adjust the pH of the system to 4.0–5.0, and obtain the impregnation solution; The molar amount of the chelating agent is 1.0–2.0 times the total molar amount of the metal ions; the precursor of the active component is cobalt acetate and cerium acetate; the precursor of the auxiliary agent is dysprosium acetate. Step 3. Contact the carrier with the impregnation solution so that the active component precursor and the auxiliary agent precursor are loaded onto the carrier; Step 4. The carrier loaded with active components and additives is dried and calcined sequentially; Step 5. The support obtained in Step 4 is subjected to reduction and activation treatment by heating under a hydrogen-containing atmosphere to obtain the catalyst.

6. The preparation method of the highly efficient CO oxidation catalyst resistant to poisoning as described in claim 5, characterized in that, The specific preparation steps of step 1 are as follows: Vanadium-tungsten-titanium raw powder is added to a phosphoric acid solution with a mass fraction of 5%-10%, and the solid-liquid ratio is controlled at 1:5-1:

15. The mixture is stirred and modified at 40-80℃. Then, γ-aminopropyltriethoxysilane is added, and the mixture is stirred and modified again at 50-90℃. After the modification is completed, the mixture is filtered, the filter cake is dried at 120℃, and then calcined at 300-500℃ for 2-5 hours to obtain the carrier. The vanadium-tungsten-titanium raw powder is composed of vanadium pentoxide, tungsten trioxide, and titanium dioxide, with a mass ratio of vanadium pentoxide, tungsten trioxide, and titanium dioxide of 1:a:b, where 5 ≤ a ≤ 10 and 60 ≤ b ≤ 100; the amount of chelating agent added is 1-5 times the total mass of metal ions; and the mass ratio of γ-aminopropyltriethoxysilane to the vanadium-tungsten-titanium raw powder is 1:100-3:

100.

7. The preparation method of the highly efficient CO oxidation catalyst resistant to poisoning as described in claim 5, characterized in that, The chelating agent is L-aspartic acid, and the dispersant is a polyethylene glycol-polypropylene glycol block copolymer.

8. The preparation method of the highly efficient CO oxidation catalyst resistant to poisoning as described in claim 5, characterized in that, The solid-liquid ratio of the carrier to the impregnation liquid in step 3 is 1:2-1:

7.

9. The method for preparing the highly efficient CO oxidation catalyst resistant to poisoning as described in any one of claims 6-8, characterized in that, The calcination parameters in step 4 are: heating at 5℃ / min to 450-550℃ and calcining for 3-5 hours; the hydrogen-containing atmosphere in step 5 is a mixed atmosphere of H2 / N2, wherein the volume fraction of H2 is 1%-5% and the volume fraction of N2 is 95-99%; the heating temperature for reduction activation is 200-400℃ and the reduction activation time is 1-4 hours.

10. The application of the highly efficient anti-poisoning CO oxidation catalyst according to any one of claims 1-4 or the catalyst prepared by the preparation method according to any one of claims 5-9 in the catalytic oxidation of carbon monoxide.

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