Sulfur-resistant and water-resistant Pt-based catalyst as well as preparation and application thereof

Abstract

The invention discloses a sulfur-resistant and water-resistant Pt-based catalyst as well as a preparation method and application thereof. A mechanochemical coupling one-pot in-situ self-assembly synthesis strategy is adopted, a template agent, acetic acid, hydrochloric acid, a phosphorus source and an aluminum source are directly and mechanically mixed with platinum salt and subjected to heat treatment and roasting, so that an active component Pt is uniformly dispersed on the inner surface and the outer surface of mesoporous AlPO, and the method is simple in process, green, environmentally friendly and free of organic solvent use and emission. The prepared catalyst shows good CO adsorption performance and excellent low-temperature catalytic activity, and complete conversion of CO can be realized at 140 DEG C; and the catalyst can continuously run for 15 hours in simulated complex industrial flue gas containing 10 vol% of water vapor and 2000 ppm of SO2 at the temperature of 250 DEG C, and a new material and a new technology with good application prospects are provided for low-temperature, efficient and stable removal of CO in the industrial flue gas.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, specifically relating to a sulfur- and water-resistant Pt-based catalyst and its preparation method, and its application in catalytic CO oxidation and purification of industrial flue gas. Background Technology

[0002] Carbon monoxide (CO), as a toxic gaseous pollutant, poses a persistent threat to the ecological environment and public health. Industrial flue gas emitted from steel mills, coking plants, coal-fired power plants, and motor vehicles has a complex composition, typically containing not only CO (500-10000 ppm) but also high concentrations of water vapor (5-15 vol%) and SO2 (200-2000 ppm). Under low-temperature conditions (<200 ℃), CO can synergistically promote the formation of secondary sulfate aerosols with SO2 / SO3, exacerbating smog pollution. Therefore, in the process of promoting the "dual-carbon" strategy, achieving efficient purification of CO in flue gas (reducing it to <50 ppm) has become a common requirement for energy-intensive industries.

[0003] Catalytic oxidation (2CO + O2 → 2CO2) is considered one of the most promising purification technologies due to its high efficiency and low energy consumption. Currently used CO catalytic oxidation catalysts mainly include non-noble metal oxides such as Co, Cu, and Mn, as well as noble metal systems such as Pt and Pd. The supports are mostly metal oxides or molecular sieves such as TiO2, CeO2, and Al2O3. Non-precious metal catalysts have lower costs, but their low-temperature activity is insufficient and they are easily poisoned and deactivated in sulfur-containing or water-containing atmospheres. Although precious metal Pt-based catalysts have excellent low-temperature activity, they still face two major challenges in actual industrial flue gas environments: (1) Water vapor interference: Water molecules compete with CO for adsorption at active sites, inhibiting the reaction; at the same time, high-temperature water vapor environment can lead to sintering of the support and collapse of the pore structure, resulting in a decrease in activity; (2) SO2 poisoning: SO2 is chemically adsorbed on the catalyst surface and converted into stable sulfate species (such as Al2(SO4)3, PtSO4), covering active sites and blocking pores. This process is often irreversible. In particular, in typical flue gas such as steel sintering and coking, SO2 and H2O coexist to form a "synergistic poisoning" effect, which further accelerates catalyst deactivation.

[0004] Chinese patent CN 116393122B describes a manganese-based catalyst, OMS-2-X, modified with alkaline earth metal (Ca, Mg, Sr) doping. Under anhydrous and sulfur-free reaction conditions, it achieves complete CO conversion within a temperature range of 120-150 °C and exhibits stability for up to 20 hours in an atmosphere containing 80 ppm SO2 and 5 vol% water vapor within the same temperature range, demonstrating good low-temperature activity and a certain degree of sulfur and water resistance. However, the long-term performance of this catalyst in harsh environments commonly found in industrial flue gas, characterized by high concentrations of SO2 (typically >500 ppm) and high humidity (water vapor content often >10 vol%), still requires further verification and improvement. While most existing Pt-based catalysts have improved their sulfur resistance to some extent through support modification, their ignition temperatures remain relatively high (>170 °C), and their long-term stability is insufficient in environments with even higher SO2 concentrations (>500 ppm) and high humidity (>10 vol% H2O). Chinese patent CN 117123259A describes a sulfur-resistant Pt-TiO2 catalyst prepared by modifying TiO2 with ammonium phosphomolybdate and anchoring Pt using its large heteropoly anions. This catalyst achieves complete CO conversion at 175 °C and operates stably in industrial flue gas at 220 °C with 50 ppm SO2 + 10 vol% H2O, exhibiting excellent toxicity resistance. However, its ignition temperature remains relatively high, and its low-temperature activity and tolerance to high concentrations of SO2 (>500 ppm) need further improvement. Therefore, developing catalytic materials that combine high activity at low temperatures, high water resistance, and high sulfur resistance is crucial for the large-scale application of deep CO purification technology.

[0005] Mesoporous aluminum phosphate (AlPO) is an inorganic framework material constructed by connecting PO4 tetrahedra and AlO6 octahedra through shared vertices. It possesses a tunable pore structure, high specific surface area, and unique surface acid-base properties, thus attracting widespread attention in the field of catalysis. Its surface rich in structural defects and modifiable Al-OP bonding environment provides an ideal interface platform for the anchoring and stabilization of noble metal species and the activation of oxygen species in catalytic reactions. Furthermore, aluminum phosphate materials themselves have also attracted attention in the field of catalysis due to their tunable pore structure and surface properties. In existing technologies, studies have used crystalline aluminum phosphate molecular sieves (such as AlPO-5) as supports, synthesized via a traditional hydrothermal method, and then introduced platinum noble metal active components through impregnation loading for the preferential oxidation of carbon monoxide (CO-PROX) in hydrogen-rich atmospheres (e.g., the master's thesis of Wang Changxu at Tianjin University, "Research on the Preferential Oxidation of CO in H2 using Aluminum Phosphate Molecular Sieves"). However, this technical solution has the following inherent limitations: (1) Support limitations: The crystalline aluminum phosphate molecular sieve used has regular micropores and relatively hydrophilic surface properties. Its structure is not conducive to repelling water molecules in a high humidity environment, and its chemical stability in a high concentration SO2 environment has not been confirmed; (2) Disadvantages of preparation methods: The traditional hydrothermal or solvent method synthesis steps are cumbersome and have a long cycle. Moreover, the post-loading process is difficult to achieve uniform dispersion and firm anchoring of active components in the support, which can easily lead to migration and aggregation of noble metals during the reaction process, thereby reducing activity and stability; (3) Limited application scenarios: The relevant studies mainly focus on the preferential oxidation of CO under hydrogen-rich conditions, which is an ideal or mild reaction atmosphere (no CO2, SO2), and do not involve the applicability in the extreme harsh environment of simulating real industrial flue gas (containing high concentration of CO2, more than 10 vol% water vapor, and 2000 ppm SO2). In addition, although mesoporous aluminum phosphate molecular sieves have potential advantages such as high specific surface area, adjustable pores, and few surface hydroxyl groups (intrinsic hydrophobic tendency), their traditional synthesis methods rely on organic solvents. Therefore, developing a green and efficient method to in-situ and highly disperse platinum active centers in an amorphous mesoporous aluminum phosphate framework, enabling them to perform exceptionally well in the purification of complex industrial flue gas, has become a pressing technical challenge in this field. Summary of the Invention

[0006] To address the problems of existing Pt-based catalyst preparation processes relying on organic solvents, involving cumbersome steps, and poor stability due to the easy migration and aggregation of active components, this invention provides a green and efficient method for preparing ordered mesoporous aluminum phosphate-supported Pt-based catalysts. By directly introducing platinum precursors into the synthesis system, in-situ embedding and high dispersion of Pt species are achieved during the formation of the AlPO framework, thereby constructing a composite catalytic material with stable active sites, large specific surface area, mesoporous channels, and optimized interface properties. This invention simplifies the process, avoids the use of organic solvents, and provides a new technical route for developing CO oxidation catalysts with both high and low temperature activity and excellent water and sulfur resistance.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: One of the objectives of this invention is to protect a sulfur- and water-resistant Pt-based catalyst, which comprises an active component and a support, wherein the active component is Pt and the support is mesoporous aluminum phosphate.

[0008] Furthermore, based on the total mass of the catalyst, the mass percentage of Pt is 0.1-1.5%.

[0009] A second objective of this invention is to protect the preparation method of the Pt-based catalyst, which includes the following steps: (1) Mix the template agent, acetic acid, hydrochloric acid, phosphorus source, aluminum source and platinum salt, stir mechanically and then heat treat; (2) The precursor obtained after heat treatment is calcined in an air atmosphere to obtain the Pt-based catalyst.

[0010] Further, the template agent mentioned in step (1) is one or more of the triblock copolymers F127, P123, and F108.

[0011] Further, the phosphorus source mentioned in step (1) is one or more of orthophosphoric acid, trimethyl phosphate, tricresyl phosphate, and ammonium dihydrogen phosphate.

[0012] Further, the aluminum source mentioned in step (1) is one or more of aluminum acetylacetonate, aluminum nitrate nonahydrate, aluminum isopropoxide, and nano alumina sol.

[0013] Further, the platinum source mentioned in step (1) is one or more of tetraammineplatinum nitrate, chloroplatinic acid, and bis(2,4-pentanedione)platinum(II).

[0014] Furthermore, the molar ratio of template agent, acetic acid, hydrochloric acid, phosphorus source and aluminum source used in step (1) is 0.119:104.9:23.9:10:10.

[0015] Furthermore, the mechanical stirring time in step (1) is 2-4 h.

[0016] Furthermore, the heat treatment in step (1) is performed at a temperature of 60-100 °C for a time of 12-48 h.

[0017] Furthermore, the roasting temperature in step (3) is 350-600 ℃ and the time is 2-6 h.

[0018] A third objective of this invention is to protect the application of the Pt-based catalyst.

[0019] Furthermore, the Pt-based catalyst can be used for the catalytic oxidation of carbon monoxide or the removal of CO from industrial flue gas.

[0020] Furthermore, when the Pt-based catalyst is used for the removal of CO from industrial flue gas, the reaction temperature is 30-200℃.

[0021] The advantages of this invention are: (1) Fundamental innovation of the support system: In terms of support selection, this invention abandons the traditional crystalline aluminum phosphate molecular sieve with microporous structure and selects amorphous mesoporous aluminum phosphate (AlPO) as the support for the first time. This material has a mesoporous structure (pore size 2-15 nm), which is conducive to efficient mass transfer between reactants and products. Its surface hydroxyl concentration is low, exhibiting intrinsic hydrophobic properties, which can effectively inhibit the competitive adsorption of water molecules at active sites, thus solving the problem of easy deactivation of traditional supports in high humidity environments from the material source.

[0022] (2) Breakthrough in Synthesis Strategy: In terms of active site construction strategy, this invention abandons the traditional two-step method of "synthesizing the support first and then loading the active component," and innovatively adopts a green synthesis strategy of solvent-free, one-pot, in-situ self-assembly. The platinum precursor is directly introduced into the synthesis system composed of template agent, aluminum source, phosphorus source and acid source, realizing the simultaneous introduction, extreme dispersion and chemical intercalation of Pt species during the formation and assembly of the mesoporous AlPO framework. This method enables Pt atoms to be highly dispersed and anchored to the support framework and inner and outer surfaces through strong Pt-O-Al / P bonding, forming structurally stable "bulk active sites" that are not easy to migrate and agglomerate, completely solving the key pain points of uneven Pt dispersion and easy sintering and deactivation in traditional post-loading processes.

[0023] (3) Comprehensive leap in performance: The catalyst prepared in this invention can achieve complete CO conversion at a low temperature of 140 °C (the activity temperature is reduced by about 70 °C compared with the traditional Pt / Al2O3 catalyst with the same Pt ​​loading), and can also operate continuously for 15 hours under the extreme and harsh conditions simulating real industrial flue gas (250 °C, 10 vol% H2O, and 2000 ppm SO2 coexistence) without any decrease in catalytic activity. This is a comprehensive performance that has never been achieved by Pt catalysts supported on crystalline aluminum phosphate, marking a generational improvement in CO oxidation catalysts from "ideal atmosphere activity" to "stability under complex operating conditions".

[0024] (4) Green preparation and industrial prospects: The entire preparation process of this invention does not use or emit organic solvents, has high atom economy, simple process, mild conditions, and has significant environmental advantages and good industrial scale-up potential. Attached Figure Description

[0025] Figure 1 Wide-angle XRD spectra of the catalysts prepared in Examples 1-4 (a) and Comparative Examples 1-2 (b).

[0026] Figure 2 The N2 adsorption-desorption isotherms (a) and pore size distribution diagram (b) of the Pt-AlPO catalysts prepared in Examples 1-4 are shown.

[0027] Figure 3 Scanning electron microscope (SEM) image (a) and transmission electron microscope (TEM) image (b) of 1.0Pt-AlPO prepared for Example 4.

[0028] Figure 4 The graph shows a comparison of the performance of the catalysts prepared in Examples 1-4 and Comparative Examples 1-4 for the catalytic oxidation of CO.

[0029] Figure 5 The graph shows the CO activity stability of 1.0Pt-AlPO prepared in Example 4 at different water vapor contents (a) at 130 °C and at different temperatures (b) with 10 vol% water vapor content.

[0030] Figure 6 The figure shows the CO activity stability of the 1.0Pt-AlPO catalyst prepared in Example 4 at 250 °C with only 2000 ppm SO2 (a) and with both 2000 ppm SO2 and 10 vol% H2O (b).

[0031] Figure 7The figure shows the CO activity stability of the 1.0Pt / AlPO and AlPO catalysts prepared for comparative examples 3 and 4 at 250 °C with only 2000 ppm SO2 (a) and with both 2000 ppm SO2 and 10 vol% H2O (b). Detailed Implementation

[0032] A sulfur- and water-resistant Pt-based catalyst, the preparation of which includes the following steps: (1) Weigh out the template agent, acetic acid, hydrochloric acid, phosphorus source and aluminum source in a molar ratio of 0.119:104.9:23.9:10:10, then mix the template agent, acetic acid, hydrochloric acid, phosphorus source and aluminum source with platinum salt, stir mechanically for 2-4 h, and then heat treat at 60-100 ℃ for 12-48 h to obtain the precursor; (2) The precursor obtained after heat treatment is calcined in air at 350-600 °C for 2-6 h to obtain Pt-AlPO catalyst, wherein the active component Pt accounts for 0.1-1.5% by mass.

[0033] In step (1), the template agent is one or more of the triblock copolymers F127, P123, and F108. The phosphorus source is one or more of orthophosphoric acid, trimethyl phosphate, tricresyl phosphate, and ammonium dihydrogen phosphate. The aluminum source is one or more of aluminum acetylacetonate, aluminum nitrate nonahydrate, aluminum isopropoxide, and nano-alumina sol. The platinum source is one or more of tetraammineplatinum nitrate, chloroplatinic acid, and bis(2,4-pentanedione)platinum(II).

[0034] To make the content of this invention easier to understand, the technical solution of this invention will be further described below with reference to specific embodiments, but this invention is not limited thereto.

[0035] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods. Example 1

[0036] 1.5 g (0.119 mmol) of F127, 6 ml (104.9 mmol) of acetic acid, 2 ml (23.9 mmol) of concentrated hydrochloric acid, 5 mmol of phosphoric acid, and 5 mmol of trimethyl phosphate were placed in a sealed glass bottle and stirred for 30 min to mix evenly. Then, 10 mmol of aluminum acetylacetonate was slowly added and stirred for another 30 min to mix evenly. Next, 3 mg of bis(2,4-pentanedione)platinum(II) was added and stirred for another 2 h. The mixture was then spread evenly on a watch glass and dried in a 60 ℃ oven for 48 h. Then, the temperature was increased to 550 ℃ in a muffle furnace at a rate of 1 ℃ / min and calcined for 4 h. After natural cooling, a catalyst product with a Pt loading of 0.1% was obtained, denoted as 0.1Pt-AlPO. Example 2

[0037] 1.5 g (0.119 mmol) of F127, 6 ml (104.9 mmol) of acetic acid, 2 ml (23.9 mmol) of concentrated hydrochloric acid, 5 mmol of phosphoric acid, and 5 mmol of trimethyl phosphate were placed in a sealed glass bottle and stirred for 30 min to mix evenly. Then, 10 mmol of aluminum acetylacetonate was slowly added and stirred for another 30 min to mix evenly. Next, 8.6 mg of bis(2,4-pentanedione)platinum(II) was added and stirred for another 2 h. The mixture was then spread evenly on a watch glass and dried in a 60 ℃ oven for 48 h. Then, the temperature was increased to 550 ℃ in a muffle furnace at a rate of 1 ℃ / min and calcined for 4 h. After natural cooling, a catalyst product with a Pt loading of 0.3% was obtained, denoted as 0.3Pt-AlPO. Example 3

[0038] 1.5 g (0.119 mmol) of F127, 6 ml (104.9 mmol) of acetic acid, 2 ml (23.9 mmol) of concentrated hydrochloric acid, 5 mmol of phosphoric acid, and 5 mmol of trimethyl phosphate were placed in a sealed glass bottle and stirred for 30 min to mix evenly. Then, 10 mmol of aluminum acetylacetonate was slowly added and stirred for another 30 min to mix evenly. Next, 14.5 mg of bis(2,4-pentanedione)platinum(II) was added and stirred for another 2 h. The mixture was then spread evenly on a watch glass and dried in an oven at 60 ℃ for 48 h. Then, the temperature was increased to 550 ℃ in a muffle furnace at a rate of 1 ℃ / min and calcined for 4 h. After natural cooling, a catalyst product with a Pt loading of 0.5% was obtained, denoted as 0.5Pt-AlPO. Example 4

[0039] 1.5 g (0.119 mmol) of F127, 6 ml (104.9 mmol) of acetic acid, 2 ml (23.9 mmol) of concentrated hydrochloric acid, 5 mmol of phosphoric acid, and 5 mmol of trimethyl phosphate were placed in a sealed glass bottle and stirred for 30 min to mix thoroughly. Then, 10 mmol of aluminum acetylacetonate was slowly added, and stirring was continued for another 30 min to mix thoroughly. Next, 29.1 mg of bis(2,4-pentanedione)platinum(II) was added, and stirring was continued for 2 h. The mixture was then spread evenly on a watch glass and dried in a 60 ℃ oven for 48 h. The temperature was then increased to 550 ℃ in a muffle furnace at a rate of 1 ℃ / min and calcined for 4 h. After natural cooling, a catalyst product with a Pt loading of 1.0% was obtained, denoted as 1.0Pt-AlPO.

[0040] Comparative Example 1: 1.0 g F127 was dissolved in 20 ml ethanol and stirred for 30 min. Then, 1.5 ml concentrated hydrochloric acid, 0.5 g citric acid and 2.04 g aluminum isopropoxide were added and stirred for 30 min. Then, 12.4 mg chloroplatinic acid was added and stirred for 30 min. The mixture was then poured into a watch glass and dried in a 60 ℃ oven for 48 h. The temperature was then increased to 400 ℃ in a muffle furnace at a rate of 1 ℃ / min. After natural cooling, the product was obtained and denoted as 0.5Pt-Al2O3.

[0041] Comparative Example 2: 1.0 g F127 was dissolved in 20 ml ethanol and stirred for 30 min. Then, 1.5 ml concentrated hydrochloric acid, 0.5 g citric acid and 2.04 g aluminum isopropoxide were added and stirred for 30 min. Then, 25 mg chloroplatinic acid was added and stirred for 30 min. The mixture was then poured into a watch glass and dried in a 60 ℃ oven for 48 h. The temperature was then increased to 400 ℃ in a muffle furnace at a rate of 1 ℃ / min. After natural cooling, the product was obtained and denoted as 1.0Pt-Al2O3.

[0042] Comparative Example 3: 1.5 g F127, 6 ml acetic acid, 2 ml concentrated hydrochloric acid, 5 mmol orthophosphoric acid, and 5 mmol trimethyl phosphate were placed in a sealed glass bottle and stirred for 30 min to mix evenly. Then, 10 mmol of aluminum acetylacetonate was slowly added, and stirring was continued for another 30 min to mix evenly. After stirring for another 2 h, the mixture was spread evenly on a watch glass and dried in an oven at 60 ℃ for 48 h. Then, the temperature was increased to 550 ℃ in a muffle furnace at a rate of 1 ℃ / min and calcined for 4 h. After natural cooling, the undoped Pt catalyst product was obtained, denoted as AlPO.

[0043] Comparative Example 4: The AlPO prepared in Comparative Example 3 was used as a support and added to 30 ml of methanol with bis(2,4-pentanedione)platinum(II) at a mass ratio of 100:1. The mixture was stirred for 12 h, then impregnated by rotary evaporation at 60 °C, and then calcined in a muffle furnace at 400 °C. After natural cooling, the product was obtained and denoted as impregnated 1.0 Pt / AlPO.

[0044] The results were then analyzed and tested accordingly. 1. Characterization: X-ray diffraction (XRD) was performed on an X'Pert3 powder diffractometer using Cu Kα radiation (λ = 1.5418 Å) at voltages of V = 45 kV and currents of I = 40 mA. The surface micro / nanostructures of different samples were investigated using a scanning electron microscope (SEM, Hitachi S-4800, acceleration voltage 5 kV). The BET specific surface area and pore volume of various samples were evaluated on a Micromeritics TriStarⅡ3020 system, after degassing at 200 °C for 12 h prior to measurement.

[0045] 2. CO Catalytic Oxidation Performance Test: The equipment used for the performance test of the catalytic reaction was the Beijing MRT-3203-G microtubular catalyst evaluation device. Before the test, 100 mg of catalyst was used, along with 0.45 g of SiC. In the CO catalytic oxidation reaction, the CO feed gas was 1% CO and 10% CO2, with Air as the equilibrium gas, and a gas flow rate of 30-60 mL / min. The SO2 feed gas was 2000 ppm SO2, with N2 as the equilibrium gas, and a gas flow rate of 1-10 mL / min. The test temperature range was 30-200℃. The concentration of CO gas at the outlet after the reaction was analyzed using a Xi'an Runlai Instrument RL-M500 infrared gas analyzer.

[0046] result: Figure 1 The figures show the wide-angle XRD patterns of the catalysts prepared in Examples 1-4 and Comparative Examples 1-2. As can be seen from the figures, the catalysts obtained in each example do not exhibit any diffraction peaks characteristic of crystals in the range of 2θ = 5-50°, indicating that the prepared Pt-AlPO catalysts are amorphous. Furthermore, the catalysts also do not show obvious Pt or PtO diffraction peaks in this range, indicating that the Pt species in the prepared Pt-AlPO catalysts are highly dispersed, possibly existing at the scale of extremely small nanoparticles or clusters, or even partially embedded in the support framework (a). In contrast, the catalysts prepared in Comparative Examples 1-2 show obvious characteristic PtO diffraction peaks in the range of 2θ = 5-80°, indicating that the Pt species have significantly agglomerated, forming larger PtO crystallites (b).

[0047] Figure 2The figures show the N2 adsorption-desorption isotherms and pore size distribution of the Pt-AlPO catalysts prepared in Examples 1-4. As can be seen from the figures, all catalyst samples exhibit type IV isotherms, indicating that the catalysts have a mesoporous structure. At relative pressures (P / P0) between 0.7 and 1.0, all catalysts showed saturated adsorption plateaus, exhibiting H1-type hysteresis loops, indicating that these four catalysts have uniformly sized mesoporous structures (a). Meanwhile, the pore size distribution of the catalysts ranges from 2 to 15 nm. This may be because the introduction of an appropriate amount of Pt alters the acidity of the synthesis system, promoting the formation of mesoporous structures. However, if the Pt doping amount is too high, it may lead to partial pore blockage (b).

[0048] Table 1 shows the structural parameters of the Pt-AlPO catalysts prepared in Examples 1-4.

[0049] Table 1 Catalyst structural parameters

[0050] As can be seen from the table, the specific surface area of ​​the catalyst first increases and then decreases with the increase of Pt addition. This is attributed to the fact that as the amount of Pt increases, the acidity of the system increases, which increases the specific surface area. However, when too much Pt is added, it will block the sample pores, increase the pore size, and decrease the specific surface area.

[0051] Figure 3 The images show scanning electron microscope (SEM) and transmission electron microscope (TEM) images of the 1.0Pt-AlPO catalyst prepared in Example 4. As can be seen from the images, the obtained catalyst exhibits an irregular block shape with a smooth surface and no large Pt sintered blocks (a); simultaneously, the catalyst contains channels of varying sizes, indicating that the Pt metal has entered the AlPO framework and is evenly distributed (b).

[0052] Figure 4Table 2 shows the CO catalytic oxidation activity of the catalysts prepared in Examples 1-4 and Comparative Examples 1-4. As can be seen from the tables, in the temperature range of 50-200 °C, the activity of the catalysts obtained in Examples 1-4 significantly increases with increasing Pt loading and temperature. This trend stems from the preferential adsorption of CO by Pt: at low temperatures, CO occupies the surface, inhibiting O2 adsorption and activation; at higher temperatures, CO2 de-accelerates, allowing O2 to adsorb at Pt sites and dissociate into active oxygen species, thus rapidly advancing the CO oxidation reaction. Among them, 1.0Pt-AlPO exhibits excellent catalytic activity under the same conditions, achieving complete CO conversion at 140 °C. In contrast, the catalysts prepared in the comparative examples require higher temperatures to achieve complete CO conversion. These results indicate that the introduction of an appropriate amount of Pt can significantly enhance the low-to-medium temperature redox capability of Pt-AlPO catalysts, thereby accelerating the CO catalytic oxidation reaction and providing a feasible pathway for the efficient removal of CO from industrial flue gas at temperatures below 150 °C.

[0053] Table 2. Activity test results of the catalyst for selective CO oxidation (in %)

[0054] Catalyst stability is a key performance indicator for evaluating the practical industrial application value of catalysts. Figure 5 The 1.0Pt-AlPO catalyst was demonstrated to achieve a space velocity of 36,000 mL·g⁻¹. -1 ·h -1 The results of a series of stability tests under the given conditions are shown in the figure. As can be seen from the figure, at a reaction temperature of 130 °C, the catalyst maintained a 100% CO conversion rate when the water vapor content was 5, 10, and 15 vol%. Even when the water vapor content was increased to 20 vol%, the CO conversion rate remained above 95%, demonstrating good water vapor resistance (a). Based on this, the long-term operational stability of the catalyst under constant water vapor content (10 vol%) at different temperatures (120, 200, and 250 °C) was further evaluated. The results showed that after continuous reaction for 17 hours at each temperature, the CO conversion rate of 1.0Pt-AlPO did not decrease significantly and remained above 90%, indicating that the catalyst has excellent water vapor resistance over a wide temperature range (b). This is attributed to the amorphous mesoporous AlPO support having low surface energy and fewer hydrophilic hydroxyl groups. Its hydrophobic surface energy effectively repels water molecules, preventing capillary condensation of liquid water in the pores and the resulting hydrothermal sintering. Therefore, even under long-term conditions of 250 °C and 10 vol% water vapor, the catalyst's mesoporous structure can still be maintained, and the active components are not isolated or sintered.

[0055] To further evaluate the practical application potential of the 1.0Pt-AlPO catalyst in simulated sulfur-containing industrial flue gas, a study was conducted at 250℃ and a space velocity of 36000 mL·g⁻¹. -1 ·h -1 The sulfur resistance stability of the catalysts prepared under the specified conditions, as well as those prepared in comparative examples 3 and 4, was tested. The results are shown in the figures below. Figure 6 , 7 As shown. By Figure 6 As can be seen, the catalyst maintained stable CO oxidation activity for 15 hours under a continuous atmosphere of 2000 ppm SO2, without significant degradation (a). Based on this, the catalyst's tolerance to the coexistence of water vapor and SO2 was further investigated. The results showed that after 15 hours of continuous operation under conditions containing both 2000 ppm SO2 and 10 vol% water vapor, the catalytic activity of 1.0Pt-AlPO remained stable, without any downward trend (b). This may be because SO2 poisoning on the catalyst surface is usually achieved through chemisorption and oxidation to sulfate. In the Pt-AlPO catalyst, Pt nanoparticles are highly dispersed and partially embedded in the framework, reducing the number of exposed metal sites on the surface. This structure reduces the chemisorption affinity for SO2 and makes the potentially generated surface sulfate species unstable or isolated, making it difficult to form a continuous capping layer, thus maintaining the unobstructed reaction pathway. The "in-situ self-assembly-encapsulation" strategy enables strong interactions between Pt species and the AlPO support through Pt-O-Al / P bonds. This bonding not only stabilizes the Pt nanoparticles, preventing their migration and aggregation, but also modulates the electronic state of Pt at the interface, enhancing its preferential adsorption and activation capacity for CO, while relatively weakening its adsorption strength for H2O and SO2, thus improving its anti-poisoning ability from a thermodynamic and kinetic perspective. In contrast, [the following text is incomplete and requires further context to translate accurately]. Figure 7 As can be seen, the activity of the pure mesoporous AlPO prepared in Comparative Example 3 decreased significantly to zero after 0.5 h under conditions containing 2000 ppm SO2 and simultaneously containing 2000 ppm SO2 and 10 vol% water vapor. In contrast, the activity of the 1.0 Pt / AlPO prepared by the conventional impregnation method in Comparative Example 4 decreased after 2 h in an atmosphere containing only 2000 ppm SO2, reaching 14.5% after 13.5 h; under conditions containing 2000 ppm SO2 and 10 vol% water vapor, the activity of the 1.0 Pt / AlPO decreased to 13.5% after 2 h. This indicates that neither pure AlPO nor the 1.0 Pt / AlPO catalyst prepared by the impregnation-supported method possesses SO2 tolerance. These results demonstrate that the catalyst obtained in this invention exhibits excellent comprehensive tolerance to complex reaction environments of high temperature, high sulfur, and high humidity, showing promising prospects for industrial application.

[0056] In summary, this invention successfully achieved high dispersion and stable anchoring of Pt in a hydrophobic mesoporous aluminum phosphate support through a green process, yielding a Pt-AlPO catalyst. This catalyst not only possesses excellent low-temperature CO oxidation activity (T... 100 Furthermore, it demonstrated excellent long-term operational stability in harsh environments simulating real industrial flue gas (10 vol% water vapor, 2000 ppm SO2) at 120℃. Therefore, this invention provides a highly competitive and environmentally friendly technical route for developing CO deep purification catalysts suitable for complex flue gas conditions in steel, coking, and coal-fired power plants, with broad application prospects.

[0057] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. A sulfur- and water-resistant Pt-based catalyst, comprising an active component Pt and a support, characterized in that: The support is mesoporous aluminum phosphate; wherein, based on the total mass of the catalyst, the mass percentage of Pt is 0.1-1.5%.

2. A method for preparing a Pt-based catalyst as described in claim 1, characterized in that: Includes the following steps: (1) Mix the template agent, acetic acid, hydrochloric acid, phosphorus source, aluminum source and platinum salt, stir mechanically and then heat treat; (2) The precursor obtained after heat treatment is calcined in an air atmosphere to obtain the Pt-based catalyst.

3. The method for preparing the Pt-based catalyst according to claim 2, characterized in that: The template agent is one or more of F127, P123, and F108; the phosphorus source is one or more of orthophosphoric acid, trimethyl phosphate, tricresyl phosphate, and ammonium dihydrogen phosphate; the aluminum source is one or more of aluminum acetylacetonate, aluminum nitrate nonahydrate, aluminum isopropoxide, and nano-alumina sol; and the platinum source is one or more of tetraammineplatinum nitrate, chloroplatinic acid, and bis(2,4-pentanedione)platinum(II).

4. The method for preparing the Pt-based catalyst according to claim 2, characterized in that: The molar ratio of template agent, acetic acid, hydrochloric acid, phosphorus source and aluminum source used in step (1) is 0.119:104.9:23.9:10:

10.

5. The method for preparing the Pt-based catalyst according to claim 2, characterized in that: The mechanical stirring time in step (1) is 2-4 hours.

6. The method for preparing the Pt-based catalyst according to claim 2, characterized in that: The heat treatment in step (1) is performed at a temperature of 60-100 °C for 12-48 h.

7. The method for preparing the Pt-based catalyst according to claim 2, characterized in that: The roasting temperature in step (3) is 350-600 ℃ and the time is 2-6 h.

8. The application of the Pt-based catalyst as described in claim 1 in the catalytic oxidation of carbon monoxide.

9. The application of a Pt-based catalyst as described in claim 1 in CO removal from industrial flue gas.

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