A noble metal-based carbon monoxide oxidation catalyst, a preparation method and application thereof

Abstract

The application relates to the technical field of carbon monoxide oxidation catalysts, and discloses a noble metal-based carbon monoxide oxidation catalyst and a preparation method and application thereof. The preparation method of the noble metal-based carbon monoxide oxidation catalyst comprises the following steps: preparing M-Mg-Al ternary hydrotalcite, wherein M is at least one of Fe, Co, Ni, Zn, Cu and Cr; calcining the M-Mg-Al ternary hydrotalcite; mixing the calcined hydrotalcite material with a platinum source aqueous solution or a palladium source aqueous solution, and then separating solid materials; calcining the solid materials; and reducing the powder obtained after calcination. According to the noble metal-based carbon monoxide oxidation catalyst, the carbon monoxide oxidation removal process can be stably carried out in the presence of hydrogen sulfide, and catalytic oxidation activity and sulfur-resistant reaction stability can be considered.

Description

Technical Field

[0001] This invention relates to the field of carbon monoxide oxidation catalyst technology, specifically to a noble metal-based carbon monoxide oxidation catalyst, its preparation method, and its application. Background Technology

[0002] Carbon monoxide, commonly known as coal gas, is a common atmospheric pollutant. It is colorless, odorless, tasteless, and non-irritating, but highly toxic and difficult to liquefy or solidify. The main source of carbon monoxide is the incomplete combustion of carbon-containing substances. Industrial furnaces, domestic boilers and stoves, as well as internal combustion engines and vehicle exhaust are the primary sources of carbon monoxide pollution. Even extremely low concentrations of carbon monoxide can enter the human body through the respiratory tract and cause poisoning. Therefore, controlling the concentration of carbon monoxide in the atmosphere is of great significance for human health and environmental protection.

[0003] In some chemical production processes, the exhaust gas contains low concentrations of CO (<20,000 ppm). Recovery costs for this type of exhaust gas are high. To meet emission requirements, adsorption, photocatalysis, low-temperature plasma conversion, and combustion are commonly used to remove CO. Among these methods, catalytic oxidation, which introduces a highly efficient catalyst to reduce the combustion temperature, has attracted widespread attention due to its simplicity and high removal efficiency. Currently, many catalysts for the catalytic oxidation of low-concentration CO have been publicly reported, typically using noble metals such as Pt and Au as active components. However, many chemical plants' CO-containing exhaust gases often contain low concentrations of sulfides (<50 ppm, including H2S and COS) due to the influence of preceding processes. These sulfur compounds have a strong poisoning effect on noble metal catalysts, easily leading to catalyst deactivation. Developing noble metal catalysts that balance high carbon monoxide oxidation activity with good sulfur resistance has become an important direction for catalyst development.

[0004] Hydrotalcite, also known as layered dihydroxy composite metal hydroxide, is a layered material composed of hydroxides of two metals. Due to its structural characteristics such as atomic-level dispersion of metal atoms in the layers, tunable types of metal cations and intercalated anions, confinement effect, and memory effect, it can be used to construct a wide variety of inorganic functional materials. In recent years, the preparation of supported metal catalysts using the topological transformation method of layered metal hydroxide structure has become a new hot topic in the utilization of hydrotalcite. This method utilizes the layered structure of hydrotalcite as a precursor, leveraging its lattice positioning effect and the advantages of high dispersion of metal cations in the main layers and the orientational arrangement of anions in the interlayers. After calcination / reduction, high-performance catalytic materials with preferential orientation of active sites, high dispersion, and stable dispersion can be obtained. Catalytic materials prepared using hydrotalcite as a precursor have also been applied in the oxidation of carbon monoxide. Patent application CN106881110A describes a three-step method of co-precipitation, deposition, precipitation, and liquid-phase reduction to prepare a palladium catalyst suitable for the oxidation of carbon monoxide in the presence of water vapor. A palladium precursor was loaded onto the surface of a pre-prepared nickel-aluminum layered double hydroxide (LDH) via deposition, followed by sodium borohydride liquid-phase reduction to obtain palladium particles with an average particle size of 1.4 nm. This catalyst exhibited good stability in the carbon monoxide oxidation reaction under conditions of water vapor coexistence. Patent application CN107649129B discloses a method for preparing a monolithically structured gold catalyst. In the preparation of this monolithically structured gold catalyst, metal oxide-based LDH nanosheets are first epitaxially grown on the monolithically structured substrate to form a monolithically structured support, followed by the loading of gold nanoparticles onto the monolithically structured support. This catalyst exhibited good low-temperature activity in the carbon monoxide oxidation reaction.

[0005] The study found that catalysts prepared with hydrotalcite structures or their topologies exhibit good reactivity in oxidation reactions. However, given the complex real-world industrial waste gas environment, the reaction stability of the catalysts in the presence of poisons such as sulfides needs to be considered. Summary of the Invention

[0006] The purpose of this invention is to address the treatment of low-concentration CO tail gas in industrial production processes, including coal chemical engineering, by providing a noble metal-based carbon monoxide oxidation catalyst, its preparation method, and its application, in order to improve the catalytic stability of the catalyst in the presence of sulfides (such as hydrogen sulfide). This invention utilizes a support with highly dispersed metal additives, obtained through a topological transformation of the hydrotalcite structure, to support active metals Pt and / or Pd. Specifically, firstly, an M-Mg-Al ternary hydrotalcite is prepared via co-precipitation, achieving high atomic-level dispersion of the metal additive M. Subsequently, by controlling the calcination conditions, a support with a layered topological structure of hydrotalcite is formed. Next, by controlling the pH of the impregnation solution, an active metal platinum precursor is introduced into the interstices of the layered structure of the support, followed by calcination-reduction to form a supported catalyst with highly dispersed Pt / Pd-M alloy particles. This preparation method utilizes the unique lamellar confinement and memory effects of the hydrotalcite structure, resulting in metal alloy particles with a small average particle size and unique surface structure, while simultaneously forming a strong metal-support interaction. This catalyst exhibits good catalytic activity in the oxidation of carbon monoxide, has a low activation temperature, and also shows good catalytic stability in a hydrogen sulfide atmosphere.

[0007] To achieve the above objectives, the present invention provides a noble metal-based carbon monoxide oxidation catalyst containing a support and an active component supported on the support. The active component is Pt and / or Pd. The support is formed by calcination and reduction of M-Mg-Al ternary hydrotalcite, wherein M is at least one of Fe, Co, Ni, Zn, Cu and Cr, and Pt and / or Pd form alloy particles with M.

[0008] Preferably, based on the total weight of the noble metal-based carbon monoxide oxidation catalyst, the content of Mg as oxide is 10-40% by weight, the content of Al as oxide is 20-60% by weight, the content of M as oxide is 0.5-10% by weight, and the content of Pt and / or Pd as metal elements is 0.1-1% by weight.

[0009] This invention also provides a method for preparing a noble metal-based carbon monoxide oxidation catalyst, the method comprising the following steps:

[0010] (1) Prepare M-Mg-Al ternary hydrotalcite, wherein M is at least one of Fe, Co, Ni, Zn, Cu and Cr;

[0011] (2) The M-Mg-Al ternary hydrotalcite was calcined;

[0012] (3) The hydrotalcite material after calcination in step (2) is mixed with an aqueous solution of the precious metal precursor, and then the solid material is separated.

[0013] (4) Calcine the solid material obtained in step (3);

[0014] (5) Reduce the powder obtained after calcination in step (4).

[0015] Preferably, in step (1), the M-Mg-Al ternary hydrotalcite is prepared by coprecipitation.

[0016] Preferably, the precipitant used is urea or a mixture of sodium carbonate and sodium hydroxide.

[0017] Preferably, the metal salt precursor used is a nitrate and / or chloride, with nitrate being the most preferred.

[0018] Preferably, in step (2), the calcination conditions include: a temperature of 200-500℃ and a time of 3-6h.

[0019] Preferably, in step (3), the noble metal precursor is at least one of chloroplatinic acid, platinum chloride, platinum nitrate, platinum acetylacetonate, palladium chloride, palladium nitrate, and palladium acetate.

[0020] Preferably, the specific operation process of step (3) is as follows: disperse the hydrotalcite material in the aqueous solution of the noble metal precursor, adjust the pH value of the obtained suspension to 5-9, stir in a constant temperature water bath for 5-48 hours, separate the solid and wash and dry it.

[0021] Preferably, the temperature of the constant temperature water bath is 60-90℃.

[0022] Preferably, the specific operation of step (4) is as follows: the solid material is heated to 400-600℃ at a heating rate of 1-3℃ / min and calcined for 3-6 hours.

[0023] Preferably, in step (5), the reduction process is carried out in an atmosphere containing hydrogen and a protective gas, wherein the hydrogen content in the atmosphere containing hydrogen and a carrier gas is 8-15 vol.

[0024] Preferably, the reduction conditions include: a temperature of 300-500℃ and a time of 1-3 hours.

[0025] The present invention also provides a noble metal-based carbon monoxide oxidation catalyst prepared by the above method.

[0026] The present invention also provides the application of the above-mentioned noble metal-based carbon monoxide oxidation catalyst as a catalyst for carbon monoxide oxidation reaction.

[0027] Preferably, the reaction gas used in the carbon monoxide oxidation process contains less than 50 ppm of sulfides.

[0028] The technical solution of the present invention has the following advantages:

[0029] (1) Compared with other carbon monoxide oxidation catalysts, the noble metal-based carbon monoxide oxidation catalyst of the present invention can achieve highly selective oxidation of sulfides (such as H2S) to sulfur dioxide, reduce the adsorption and deposition of sulfides on the catalyst, and extend the catalyst life.

[0030] (2) Compared with other carbon monoxide oxidation catalysts, the noble metal-based carbon monoxide oxidation catalyst of the present invention exhibits good catalytic stability in the presence of sulfides (such as H2S). Specifically, at a space velocity of 10000 h⁻¹, it exhibits good catalytic stability. -1 With a reaction temperature of 250℃, an inlet CO concentration of 6000ppm, and the presence of 50ppm hydrogen sulfide, the CO conversion rate remained above 99% after a reaction time of 200h.

[0031] The noble metal-based carbon monoxide oxidation catalyst of this invention has a simple composition and excellent performance, showing promising prospects for industrial application. Based on the catalyst of this invention, a low-concentration carbon monoxide catalytic removal technology can be formed, applicable to various low-concentration carbon monoxide removal conditions, including those involving the presence of sulfides. It can reduce the carbon monoxide concentration in exhaust gas to below 50 ppm, and can be widely used in exhaust gas treatment in petrochemical, steel, industrial kilns, and waste incineration processes, which is of great significance for protecting the atmospheric environment and safeguarding human health. Attached Figure Description

[0032] Figure 1 The catalyst PtFe / MgAlO in Example 1 x A graph showing the conversion rate of CO oxidation by catalytic oxidation;

[0033] Figure 2 The catalyst PtFe / MgAlO in Example 1 x SEM and TEM images;

[0034] Figure 3 The catalyst PtFe / MgAlO in Example 1 x HRTEM and STEM-HAADF plots;

[0035] Figure 4 The catalyst Pt / Fe / MgAlO in Comparative Example 1 x TEM image. Detailed Implementation

[0036] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0037] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0038] The noble metal-based carbon monoxide oxidation catalyst of the present invention contains a support and an active component supported on the support. The active component is Pt and / or Pd. The support is formed by calcination and reduction of M-Mg-Al ternary hydrotalcite, wherein M is at least one of Fe, Co, Ni, Zn, Cu and Cr, and Pt and / or Pd form alloy particles with M (i.e. Pt / Pd-M alloy particles).

[0039] In the noble metal-based carbon monoxide oxidation catalyst of the present invention, Pt / Pd-M alloy particles are highly dispersed in the catalyst. The average particle size of the Pt / Pd-M alloy particles is 4-8 nm.

[0040] In the noble metal-based carbon monoxide oxidation catalyst of the present invention, based on the total weight of the noble metal-based carbon monoxide oxidation catalyst, the content of Mg as oxide can be 10-40% by weight, preferably 25-40% by weight; the content of Al as oxide can be 20-60% by weight, preferably 40-60% by weight; the content of M as oxide can be 0.5-10% by weight, preferably 1-8% by weight; and the content of Pt as metal element can be 0.1-1% by weight, preferably 0.5-0.8% by weight.

[0041] The noble metal-based carbon monoxide oxidation catalyst of the present invention can still stably carry out the carbon monoxide oxidation and removal process in the presence of hydrogen sulfide, and can take into account both catalytic oxidation activity and sulfur resistance reaction stability.

[0042] The preparation method of the noble metal-based carbon monoxide oxidation catalyst of the present invention includes the following steps:

[0043] (1) Prepare M-Mg-Al ternary hydrotalcite, wherein M is at least one of Fe, Co, Ni, Zn, Cu and Cr;

[0044] (2) The M-Mg-Al ternary hydrotalcite was calcined;

[0045] (3) The hydrotalcite material after calcination in step (2) is mixed with an aqueous solution of the precious metal precursor, and then the solid material is separated.

[0046] (4) Calcine the solid material obtained in step (3);

[0047] (5) Reduce the powder obtained after calcination in step (4).

[0048] In step (1), the M-Mg-Al ternary hydrotalcite is prepared by a co-precipitation method. The precipitant used can be urea or a mixture of sodium carbonate and sodium hydroxide.

[0049] In step (1), the metal salt precursor used in the preparation of M-Mg-Al ternary hydrotalcite can be nitrate and / or chloride, preferably nitrate.

[0050] In step (1), the synthesized hydrotalcite can be represented as:

[0051]

[0052] Among them, M 2+ It can be Mg 2+ Ni 2+ Co 2+ Zn 2+ Cu 2+ M 3+ It can be Fe 3+ Al 3+ .

[0053] When a mixture of sodium carbonate and sodium hydroxide alkaline solution is used as a precipitant, the content of the alkaline solution can be calculated by the following formula:

[0054] [OH - ]=2([Ni 2+ ]+[Mg 2+ ]+[Al 3+ ])

[0055] CO3 2- ] = 0.5[Al 3+ ]

[0056] When urea is used as a precipitant, the concentration of urea in the solution can be 2-5 mol / L.

[0057] In one specific embodiment, when using a mixture of sodium carbonate and sodium hydroxide alkaline solution as a precipitant, the specific operation process for preparing M-Mg-Al ternary hydrotalcite is as follows: A certain amount of Al(NO3)3·9H2O, Mg(NO3)2·6H2O, and M are fully dissolved in 150 mL of deionized water. x+ (NO3) x·yH2O, denoted as solution A; a certain amount of Na2CO3 (0.5-1.2 mol / L) and NaOH (1-2 mol / L) are dissolved in 150 mL of deionized water, denoted as solution B; solutions A and B are added dropwise to a three-necked flask placed in a 65℃ water bath using a separatory funnel, and the mixture in the three-necked flask is stirred vigorously; during the mixing of solutions A and B, the pH value of the mixed solution is controlled by adding NaOH solution (1-2 mol / L) dropwise to ensure complete precipitation of metal ions in the solution; after the mixture of solutions A and B is completed, the resulting mixed solution is stirred vigorously in a 65℃ water bath for 24 h, and then the precipitate is washed with deionized water. After washing, the sample is dried in a forced-air drying oven for 12 h to obtain M-Mg-Al ternary hydrotalcite.

[0058] In another specific embodiment, when urea is used as a precipitant, the specific operation process for preparing M-Mg-Al ternary hydrotalcite is as follows: a certain amount of M... x+ (NO3) x ·yH2O, Mg(NO3)2·6H2O, Al(NO3)3·9H2O and urea are simultaneously dissolved in 300mL of deionized water, of which Mg 2+ Al 3+ M x+ The total concentration of the three metal cations was 0.15 mol / L, and the concentration of urea was 2-5 mol / L. The solution was then placed in a 96℃ water bath and stirred vigorously for 24 hours. After stirring, the resulting hydrotalcite dispersion was filtered and washed thoroughly with deionized water until the pH of the filtrate was neutral. Finally, the hydrotalcite was dried to obtain M-Mg-Al ternary hydrotalcite.

[0059] In step (2), the calcination conditions may include: a temperature of 200-500℃ and a time of 3-6h.

[0060] In one specific embodiment, the specific operation process of calcining the M-Mg-Al ternary hydrotalcite is as follows: the M-Mg-Al ternary hydrotalcite is placed in the center of a quartz boat, the quartz boat containing the sample is placed in the center of the heating section of the quartz tube of a tubular furnace, and the temperature is raised from room temperature to a certain temperature at a constant heating rate in the presence of a protective gas (such as Ar or N2), and calcined at a constant temperature for a period of time in the atmosphere of the protective gas. After the calcination is completed, the sample is naturally cooled to room temperature in the atmosphere of the protective gas, and then sealed and stored for later use.

[0061] In step (3), the noble metal precursor may be at least one of chloroplatinic acid, platinum chloride, platinum nitrate, platinum acetylacetonate, palladium chloride, palladium nitrate and palladium acetate, preferably chloroplatinic acid and / or palladium nitrate.

[0062] Taking chloroplatinic acid as a noble metal precursor as an example, this invention utilizes the "memory effect" of hydrotalcite to insert chloroplatinic acid ions into the interlayer spaces of hydrotalcite. The "memory effect" refers to the phenomenon where a sample of hydrotalcite calcined for a certain time at a specific temperature (at which point the sample is typically a composite oxide of metal ions in the hydrotalcite) is added to a solution containing a certain anion, and its structure can partially recover to the ordered layered structure of hydrotalcite. In the method described in this invention, this effect is used to insert negatively charged chloroplatinic acid anions, generated after the hydrolysis of chloroplatinic acid, into the interlayer spaces of the hydrotalcite. The attraction between the positively charged interlayer spaces and the negatively charged intercalated chloroplatinic acid ions causes platinum atoms to be oriented and uniformly arranged between the hydrotalcite layers.

[0063] In step (3), the concentration of the aqueous solution of the noble metal precursor can be 0.1-1 mmol / L, and most preferably 0.25 mmol / L.

[0064] In the method described in this invention, the specific operation process of step (3) can be as follows: disperse the hydrotalcite material in the aqueous solution of the noble metal precursor, adjust the pH of the resulting suspension to 5-9, then stir in a constant temperature water bath for 5-48 hours, separate the solid, and wash and dry it. The temperature of the constant temperature water bath can be 60-90℃.

[0065] In one specific embodiment, the operation process of step (3) is as follows: the calcined hydrotalcite material is uniformly dispersed in chloroplatinic acid solution, and the pH of the suspension is adjusted to 5-9 using dilute hydrochloric acid (0.5mol / L) or sodium hydroxide solution (0.5mol / L); then the suspension is stirred in a water bath at 60-90℃ for 24h; after stirring, it is washed with deionized water until neutral, and dried for later use.

[0066] In the method described in this invention, the specific operation of step (4) is as follows: the solid material is heated to 400-600℃ at a heating rate of 1-3℃ / min and calcined for 3-6 hours.

[0067] In step (5), the reduction process is carried out in an atmosphere containing hydrogen and a protective gas, wherein the hydrogen content in the atmosphere containing hydrogen and a carrier gas is 8-15 vol%. The protective gas can be an inert gas (such as Ar) or nitrogen.

[0068] In step (5), the reduction conditions may include: a temperature of 300-500℃ and a time of 1-3h.

[0069] In the method described in this invention, the amounts of various reactants are such that, based on the total weight of the noble metal-based carbon monoxide oxidation catalyst, the content of Mg as oxide is 10-40% by weight, preferably 25-40% by weight; the content of Al as oxide is 20-60% by weight, preferably 40-60% by weight; the content of M as oxide is 0.5-10% by weight, preferably 1-8% by weight; and the content of Pt as metal element is 0.1-1% by weight, preferably 0.5-0.8% by weight.

[0070] In this invention, unless otherwise specified, the mass percentage of each component constituting the catalyst refers to the mass percentage of the corresponding component relative to the mass of the catalyst. The content of each component in the gas composition used for catalyst reduction in this invention refers to the volume percentage of the corresponding component relative to the total gas volume.

[0071] The present invention also provides a noble metal-based carbon monoxide oxidation catalyst prepared by the above method. The noble metal-based carbon monoxide oxidation catalyst contains highly dispersed Pt / Pd-M alloy particles with a small average particle size and a unique surface structure, forming a strong metal-support interaction. This results in the catalyst exhibiting good catalytic activity in the carbon monoxide oxidation reaction, a low activation temperature, and good catalytic stability in a hydrogen sulfide atmosphere.

[0072] This invention also provides the application of the above-mentioned noble metal-based carbon monoxide oxidation catalyst as a catalyst for carbon monoxide oxidation reactions. Specifically, the noble metal-based carbon monoxide oxidation catalyst of this invention can be applied to various low-concentration carbon monoxide removal conditions, especially various low-concentration carbon monoxide removal conditions in the presence of sulfides. In one specific embodiment, the reactant gas used in the carbon monoxide oxidation reaction contains less than 50 ppm of sulfides.

[0073] Based on the precious metal-based carbon monoxide oxidation catalyst described in this invention, a low-concentration carbon monoxide catalytic removal technology can be formed. It is applicable to various low-concentration carbon monoxide removal conditions, including those with sulfides. It can reduce the carbon monoxide concentration in exhaust gas to below 50 ppm and can be widely used in exhaust gas treatment in petrochemical, steel, industrial kiln, and waste incineration processes. It is of great significance for protecting the atmospheric environment and safeguarding human health.

[0074] The following examples further illustrate the noble metal-based carbon monoxide oxidation catalyst, its preparation method, and its application according to the present invention. These examples are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following examples.

[0075] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods in the art. Unless otherwise specified, the experimental materials used in the following embodiments are commercially available.

[0076] Example 1

[0077] 3.64 g Fe(NO3)3·9H2O, 3.84 g Mg(NO3)2·6H2O, 7.88 g Al(NO3)3·9H2O, and 36.0 g urea, calculated according to their loading amounts, were simultaneously dissolved in 300.0 mL of deionized water. Among these, Mg... 2+ Al 3+ Fe 3+ The total concentration of the three metal cations was 0.15 mol / L, and the urea concentration was 2.0 mol / L. The solution was then placed in a 96℃ water bath and stirred vigorously for 24 h. After stirring, the resulting hydrotalcite dispersion was filtered and thoroughly washed with deionized water until the pH of the filtrate was neutral. Finally, the hydrotalcite was dried, and the product was named FeMgAl-LDH.

[0078] The FeMgAl-LDH powder obtained above was placed in the center of a quartz boat, and the quartz boat containing the sample was placed in the center of the heating section of the quartz tube in a tubular furnace. The FeMgAl-LDH powder was heated from room temperature to 300℃ at a heating rate of 1℃ / min under the protection of an inert gas argon flow, and then continuously calcined at a constant temperature in an inert atmosphere for a period of time. After calcination, the sample was naturally cooled to room temperature under the protection of an argon atmosphere, and then sealed and stored for later use.

[0079] Prepare a chloroplatinic acid solution with a concentration of 0.25 mmol / L, and let it stand for later use.

[0080] 2g of the calcined hydrotalcite material was uniformly dispersed in 60mL of chloroplatinic acid solution, and the pH of the suspension was adjusted to 8 using sodium hydroxide solution (0.5mol / L). The suspension was then stirred in a water bath at a specific temperature for 24 hours. After stirring, the suspension was washed with deionized water until neutral and dried for later use.

[0081] The material obtained above was heated to 500°C at a heating rate of 1°C / min and calcined in air for 4 hours.

[0082] The calcined powder was placed in a tube furnace and heated to 500°C at a constant heating rate in a 10 vol% H₂ / Ar atmosphere, followed by reduction for 2 hours. After reduction, the powder was cooled to room temperature under a 10 vol% H₂ / Ar atmosphere to obtain a Pt-based carbon monoxide oxidation catalyst, abbreviated as PtFe / MgAlO₂. x .

[0083] ICP-OES characterization revealed that the catalyst PtFe / MgAlO x Based on its total weight, the content of Mg as oxide is 33.11 wt%, the content of Al as oxide is 59.91 wt%, the content of Fe as oxide is 6.47 wt%, and the content of Pt as metal element is 0.51 wt%.

[0084] The catalyst is PtFe / MgAlO x SEM and TEM images, such as Figure 2 As shown.

[0085] Results of characterization by high-footed annular dark-field scanning transmission electron microscopy (STEM-HAADF) and high-resolution transmission electron microscopy (HRTEM) (see [link to documentation]). Figure 3 It can be determined that the catalyst PtFe / MgAlO x Pt exists in the form of Pt-Fe alloy particles, and the average particle size of the Pt-Fe alloy particles is 7 nm.

[0086] The prepared catalyst PtFe / MgAlO x The reactor was placed in a fixed-bed microreactor with a reaction tube inner diameter of 6 mm. The temperature was increased to 250 °C at a rate of 5 °C / min and held constant. The reactant gas composition was 0.6 vol% CO / 0.005 vol% H₂S / 5 vol% O₂ / 94.395 vol% CO₂, and the reaction space velocity was controlled at 10000 h⁻¹. -1 The CO concentration at the reactor outlet was detected using gas chromatography. The catalyst is PtFe / MgAlO. x The reaction results for the catalytic oxidation of CO conversion are as follows: Figure 1 As shown, from Figure 1 As can be seen, during the 200-hour long-cycle carbon monoxide oxidation reaction, the carbon monoxide conversion rate remained above 99%.

[0087] Example 2

[0088] 2.62 g Ni(NO3)2·6H2O, 3.84 g Mg(NO3)2·6H2O, 7.88 g Al(NO3)3·9H2O, and 36.0 g urea, calculated according to the loading amount, were simultaneously dissolved in 300.0 mL of deionized water. Among them, Mg... 2+ Al 3+ Ni 2+The total concentration of the three metal cations was 0.15 mol / L, and the urea concentration was 2.0 mol / L. The solution was then placed in a 96℃ water bath and stirred vigorously for 24 h. After stirring, the resulting hydrotalcite dispersion was filtered and thoroughly washed with deionized water until the pH of the filtrate was neutral. Finally, the hydrotalcite was dried, and the product was named NiMgAl-LDH.

[0089] The NiMgAl-LDH powder obtained above was placed in the center of a quartz boat, and the quartz boat containing the sample was placed in the center of the heating section of the quartz tube in a tubular furnace. The NiMgAl-LDH powder was heated from room temperature to 350°C at a heating rate of 1°C / min under the protection of an inert argon gas flow, and then continuously calcined at a constant temperature in an argon atmosphere for a period of time. After calcination, the sample was naturally cooled to room temperature under the protection of an argon atmosphere, and then sealed and stored for later use.

[0090] Prepare a chloroplatinic acid solution with a concentration of 0.25 mmol / L, and let it stand for later use.

[0091] 2g of the calcined hydrotalcite material was uniformly dispersed in 60mL of chloroplatinic acid solution, and the pH of the suspension was adjusted to 8.5 using sodium hydroxide solution (0.5mol / L). The suspension was then stirred in a water bath at a specific temperature for 24 hours. After stirring, the suspension was washed with deionized water until neutral and dried for later use.

[0092] The material obtained above was heated to 500°C at a heating rate of 1°C / min and calcined in air for 4 hours.

[0093] The calcined powder was placed in a tube furnace and heated to 500°C at a constant heating rate in a 10 vol% H₂ / Ar atmosphere, followed by reduction for 2 hours. After reduction, the powder was cooled to room temperature under a 10 vol% H₂ / Ar atmosphere to obtain a Pt-based carbon monoxide oxidation catalyst, abbreviated as PtNi / MgAlO₂. x .

[0094] Characterization by ICP-OES revealed that the catalyst PtNi / MgAlO x Based on its total weight, the content of Mg as oxide is 37.03 wt%, the content of Al as oxide is 55.03 wt%, the content of Ni as oxide is 6.96 wt%, and the content of Pt as metal element is 0.98 wt%.

[0095] Characterization results from high-resolution annular dark-field scanning transmission electron microscopy (STEM-HAADF) and high-resolution transmission electron microscopy (HRTEM) revealed that the catalyst PtNi / MgAlO xPt exists in the form of Pt-Ni alloy particles, and the average particle size of the Pt-Ni alloy particles is 8 nm.

[0096] The prepared catalyst PtNi / MgAlO x The reactor was placed in a fixed-bed microreactor with a reaction tube inner diameter of 6 mm. The temperature was increased to 250 °C at a rate of 5 °C / min and held constant. The reactant gas composition was 0.6 vol% CO / 0.005 vol% H₂S / 5 vol% O₂ / 94.395 vol% CO₂, and the reaction space velocity was controlled at 10000 h⁻¹. -1 The CO concentration at the reactor outlet was detected using gas chromatography. The results showed that during the 200-hour long-cycle carbon monoxide oxidation reaction, the carbon monoxide conversion rate remained above 99%.

[0097] Example 3

[0098] Dissolve 2.62g Co(NO3)2·6H2O, 3.84g Mg(NO3)2·6H2O, and 7.88g Al(NO3)3·9H2O completely in 150mL of deionized water, and label this solution A. Dissolve 12.75g Na2CO3 (0.8mol / L) and 6g NaOH (1.0mol / L) in 150mL of deionized water, and label this solution B. Add solutions A and B dropwise to a three-necked flask placed in a 65℃ water bath using a separatory funnel, while vigorously stirring the mixture. During the mixing process, maintain the pH of the mixed solution at 10.5 by adding NaOH solution (2.0mol / L) dropwise to ensure complete precipitation of the metal ions. After solutions A and B were mixed, the resulting mixture was stirred vigorously in a 65°C water bath for 24 hours. The precipitate was then washed with deionized water and dried in a forced-air drying oven for 12 hours. The resulting hydrotalcite sample was designated CoMgAl-LDH.

[0099] The CoMgAl-LDH powder obtained above was placed in the center of a quartz boat, and the quartz boat containing the sample was placed in the center of the heating section of the quartz tube in a tubular furnace. The CoMgAl-LDH powder was heated from room temperature to 300℃ at a heating rate of 1℃ / min under the protection of an inert argon gas flow, and then continuously calcined at a constant temperature in an argon atmosphere for a period of time. After calcination, the sample was naturally cooled to room temperature under the protection of an argon atmosphere, and then sealed and stored for later use.

[0100] Prepare a chloroplatinic acid solution with a concentration of 0.25 mmol / L, and let it stand for later use.

[0101] Take 2g of calcined hydrotalcite material and disperse it evenly in 60mL of chloroplatinic acid solution. Adjust the pH of the suspension to 6.0 using dilute hydrochloric acid solution (0.5mol / L). Then, stir the suspension in a water bath at a certain temperature for 24h. After stirring, wash with deionized water until neutral, and dry for later use.

[0102] The material obtained above was heated to 500°C at a heating rate of 1°C / min and calcined in air for 4 hours.

[0103] The calcined powder was placed in a tube furnace and heated to 500°C at a constant heating rate in a 10 vol% H₂ / Ar atmosphere, followed by reduction for 2 hours. After reduction, the powder was cooled to room temperature under a 10 vol% H₂ / Ar atmosphere to obtain a Pt-based carbon monoxide oxidation catalyst, abbreviated as PtCo / MgAlO₂. x .

[0104] ICP-OES analysis revealed that the catalyst PtCo / MgAlO x Based on its total weight, the content of Mg as oxide is 35.34 wt%, the content of Al as oxide is 59.62 wt%, the content of Co as oxide is 4.13 wt%, and the content of Pt as metal element is 0.91 wt%.

[0105] Characterization results from high-resolution annular dark-field scanning transmission electron microscopy (STEM-HAADF) and high-resolution transmission electron microscopy (HRTEM) revealed that the catalyst PtCo / MgAlO x Pt exists in the form of Pt-Co alloy particles, and the average particle size of the Pt-Co alloy particles is 4 nm.

[0106] The prepared catalyst PtCo / MgAlO x The reactor was placed in a fixed-bed microreactor with a reaction tube inner diameter of 6 mm. The temperature was increased to 250 °C at a rate of 5 °C / min and held constant. The reactant gas composition was 0.6 vol% CO / 0.005 vol% H₂S / 5 vol% O₂ / 94.395 vol% CO₂, and the reaction space velocity was controlled at 10000 h⁻¹. -1 The CO concentration at the reactor outlet was detected using gas chromatography. The results showed that during the 200-hour long-cycle carbon monoxide oxidation reaction, the carbon monoxide conversion rate remained above 99%.

[0107] Example 4

[0108] 3.64 g Fe(NO3)3·9H2O, 3.84 g Mg(NO3)2·6H2O, 7.88 g Al(NO3)3·9H2O, and 36.0 g urea, calculated according to their loading amounts, were simultaneously dissolved in 300.0 mL of deionized water. Among these, Mg... 2+ Al 3+ Fe 3+ The total concentration of the three metal cations was 0.15 mol / L, and the urea concentration was 2.0 mol / L. The solution was then placed in a 96℃ water bath and stirred vigorously for 24 h. After stirring, the resulting hydrotalcite dispersion was filtered and thoroughly washed with deionized water until the pH of the filtrate was neutral. Finally, the hydrotalcite was dried, and the product was named FeMgAl-LDH.

[0109] The FeMgAl-LDH powder obtained above was placed in the center of a quartz boat, and the quartz boat containing the sample was placed in the center of the heating section of the quartz tube in a tubular furnace. The FeMgAl-LDH powder was heated from room temperature to 300℃ at a heating rate of 1℃ / min under the protection of an inert gas argon flow, and then continuously calcined at a constant temperature in an inert atmosphere for a period of time. After calcination, the sample was naturally cooled to room temperature under the protection of an argon atmosphere, and then sealed and stored for later use.

[0110] Prepare a chloroplatinic acid solution with a concentration of 0.25 mmol / L, and let it stand for later use.

[0111] 2g of the calcined hydrotalcite material was uniformly dispersed in 70mL of chloroplatinic acid solution, and the pH of the suspension was adjusted to 8 using sodium hydroxide solution (0.5mol / L). The suspension was then stirred in a water bath at a specific temperature for 24 hours. After stirring, the suspension was washed with deionized water until neutral and dried for later use.

[0112] The material obtained above was heated to 400°C at a heating rate of 2°C / min and calcined in air for 6 hours.

[0113] The calcined powder was placed in a tube furnace and heated to 500°C at a constant heating rate in a 10 vol% H₂ / Ar atmosphere, followed by reduction for 2 hours. After reduction, the powder was cooled to room temperature under a 10 vol% H₂ / Ar atmosphere to obtain a Pt-based carbon monoxide oxidation catalyst, abbreviated as PtFe / MgAlO₂. x .

[0114] ICP-OES characterization revealed that the catalyst PtFe / MgAlO xBased on its total weight, the content of Mg as oxide is 33.06 wt%, the content of Al as oxide is 59.80 wt%, the content of Fe as oxide is 6.46 wt%, and the content of Pt as metal element is 0.68 wt%.

[0115] Characterization results from high-resolution annular dark-field scanning transmission electron microscopy (STEM-HAADF) and high-resolution transmission electron microscopy (HRTEM) revealed that the catalyst PtFe / MgAlO x Pt exists in the form of Pt-Fe alloy particles, and the average particle size of the Pt-Fe alloy particles is 7 nm.

[0116] The prepared catalyst PtFe / MgAlO x The reactor was placed in a fixed-bed microreactor with a reaction tube inner diameter of 6 mm. The temperature was increased to 250 °C at a rate of 5 °C / min and held constant. The reactant gas composition was 0.6 vol% CO / 0.005 vol% H₂S / 5 vol% O₂ / 94.395 vol% CO₂, and the reaction space velocity was controlled at 10000 h⁻¹. -1 The CO concentration at the reactor outlet was detected using gas chromatography. The results showed that during the 200-hour long-cycle carbon monoxide oxidation reaction, the carbon monoxide conversion rate remained above 99%.

[0117] Example 5

[0118] 3.64 g Fe(NO3)3·9H2O, 3.84 g Mg(NO3)2·6H2O, 7.88 g Al(NO3)3·9H2O, and 36.0 g urea, calculated according to their loading amounts, were simultaneously dissolved in 300.0 mL of deionized water. Among these, Mg... 2+ Al 3+ Fe 3+ The total concentration of the three metal cations was 0.15 mol / L, and the urea concentration was 2.0 mol / L. The solution was then placed in a 96℃ water bath and stirred vigorously for 24 h. After stirring, the resulting hydrotalcite dispersion was filtered and thoroughly washed with deionized water until the pH of the filtrate was neutral. Finally, the hydrotalcite was dried, and the product was named FeMgAl-LDH.

[0119] The FeMgAl-LDH powder obtained above was placed in the center of a quartz boat, and the quartz boat containing the sample was placed in the center of the heating section of the quartz tube in a tubular furnace. The FeMgAl-LDH powder was heated from room temperature to 300℃ at a heating rate of 1℃ / min under the protection of an inert gas argon flow, and then continuously calcined at a constant temperature in an inert atmosphere for a period of time. After calcination, the sample was naturally cooled to room temperature under the protection of an argon atmosphere, and then sealed and stored for later use.

[0120] Prepare a chloroplatinic acid solution with a concentration of 0.25 mmol / L, and let it stand for later use.

[0121] 2g of the calcined hydrotalcite material was uniformly dispersed in 80mL of chloroplatinic acid solution, and the pH of the suspension was adjusted to 8 using sodium hydroxide solution (0.5mol / L). The suspension was then stirred in a water bath at a specific temperature for 24 hours. After stirring, the suspension was washed with deionized water until neutral and dried for later use.

[0122] The material obtained above was heated to 600°C at a heating rate of 3°C / min and calcined in air for 3 hours.

[0123] The calcined powder was placed in a tube furnace and heated to 500°C at a constant heating rate in a 10 vol% H₂ / Ar atmosphere, followed by reduction for 2 hours. After reduction, the powder was cooled to room temperature under a 10 vol% H₂ / Ar atmosphere to obtain a Pt-based carbon monoxide oxidation catalyst, abbreviated as PtFe / MgAlO₂. x .

[0124] ICP-OES characterization revealed that the catalyst PtFe / MgAlO x Based on its total weight, the content of Mg as oxide is 33.03 wt%, the content of Al as oxide is 59.74 wt%, the content of Fe as oxide is 6.46 wt%, and the content of Pt as metal element is 0.77 wt%.

[0125] Characterization results from high-resolution annular dark-field scanning transmission electron microscopy (STEM-HAADF) and high-resolution transmission electron microscopy (HRTEM) revealed that the catalyst PtFe / MgAlO x Pt exists in the form of Pt-Fe alloy particles, and the average particle size of the Pt-Fe alloy particles is 7 nm.

[0126] The prepared catalyst PtFe / MgAlO x The reactor was placed in a fixed-bed microreactor with a reaction tube inner diameter of 6 mm. The temperature was increased to 250 °C at a rate of 5 °C / min and held constant. The reactant gas composition was 0.6 vol% CO / 0.005 vol% H₂S / 5 vol% O₂ / 94.395 vol% CO₂, and the reaction space velocity was controlled at 10000 h⁻¹. -1 The CO concentration at the reactor outlet was detected using gas chromatography. The results showed that during the 200-hour long-cycle carbon monoxide oxidation reaction, the carbon monoxide conversion rate remained above 99%.

[0127] Example 6

[0128] 2.62 g Ni(NO3)2·6H2O, 3.84 g Mg(NO3)2·6H2O, 7.88 g Al(NO3)3·9H2O, and 36.0 g urea, calculated according to the loading amount, were simultaneously dissolved in 300.0 mL of deionized water. Among them, Mg... 2+ Al 3+ Ni 2+ The total concentration of the three metal cations was 0.15 mol / L, and the urea concentration was 2.0 mol / L. The solution was then placed in a 96℃ water bath and stirred vigorously for 24 h. After stirring, the resulting hydrotalcite dispersion was filtered and thoroughly washed with deionized water until the pH of the filtrate was neutral. Finally, the hydrotalcite was dried, and the product was named NiMgAl-LDH.

[0129] The NiMgAl-LDH powder obtained above was placed in the center of a quartz boat, and the quartz boat containing the sample was placed in the center of the heating section of the quartz tube in a tubular furnace. The NiMgAl-LDH powder was heated from room temperature to 350°C at a heating rate of 1°C / min under the protection of an inert argon gas flow, and then continuously calcined at a constant temperature in an argon atmosphere for a period of time. After calcination, the sample was naturally cooled to room temperature under the protection of an argon atmosphere, and then sealed and stored for later use.

[0130] Prepare a chloroplatinic acid solution with a concentration of 0.25 mmol / L, and let it stand for later use.

[0131] 2g of the calcined hydrotalcite material was uniformly dispersed in 55mL of chloroplatinic acid solution, and the pH of the suspension was adjusted to 8.5 using sodium hydroxide solution (0.5mol / L). The suspension was then stirred in a water bath at a specific temperature for 24 hours. After stirring, the suspension was washed with deionized water until neutral and dried for later use.

[0132] The material obtained above was heated to 400°C at a heating rate of 2°C / min and calcined in air for 4 hours.

[0133] The calcined powder was placed in a tube furnace and heated to 500°C at a constant heating rate in a 10 vol% H₂ / Ar atmosphere, followed by reduction for 2 hours. After reduction, the powder was cooled to room temperature under a 10 vol% H₂ / Ar atmosphere to obtain a Pt-based carbon monoxide oxidation catalyst, abbreviated as PtNi / MgAlO₂. x .

[0134] Characterization by ICP-OES revealed that the catalyst PtNi / MgAlO xBased on its total weight, the content of Mg as oxide is 37.10 wt%, the content of Al as oxide is 55.15 wt%, the content of Ni as oxide is 6.97 wt%, and the content of Pt as metal element is 0.78 wt%.

[0135] Characterization results from high-resolution annular dark-field scanning transmission electron microscopy (STEM-HAADF) and high-resolution transmission electron microscopy (HRTEM) revealed that the catalyst PtNi / MgAlO x Pt exists in the form of Pt-Ni alloy particles, and the average particle size of the Pt-Ni alloy particles is 8 nm.

[0136] The prepared catalyst PtNi / MgAlO x The reactor was placed in a fixed-bed microreactor with a reaction tube inner diameter of 6 mm. The temperature was increased to 250 °C at a rate of 5 °C / min and held constant. The reactant gas composition was 0.6 vol% CO / 0.005 vol% H₂S / 5 vol% O₂ / 94.395 vol% CO₂, and the reaction space velocity was controlled at 10000 h⁻¹. -1 The CO concentration at the reactor outlet was detected using gas chromatography. The results showed that during the 200-hour long-cycle carbon monoxide oxidation reaction, the carbon monoxide conversion rate remained above 99%.

[0137] Example 7

[0138] 2.62 g Ni(NO3)2·6H2O, 3.84 g Mg(NO3)2·6H2O, 7.88 g Al(NO3)3·9H2O, and 36.0 g urea, calculated according to the loading amount, were simultaneously dissolved in 300.0 mL of deionized water. Among them, Mg... 2+ Al 3+ Ni 2+ The total concentration of the three metal cations was 0.15 mol / L, and the urea concentration was 2.0 mol / L. The solution was then placed in a 96℃ water bath and stirred vigorously for 24 h. After stirring, the resulting hydrotalcite dispersion was filtered and thoroughly washed with deionized water until the pH of the filtrate was neutral. Finally, the hydrotalcite was dried, and the product was named NiMgAl-LDH.

[0139] The NiMgAl-LDH powder obtained above was placed in the center of a quartz boat, and the quartz boat containing the sample was placed in the center of the heating section of the quartz tube in a tubular furnace. The NiMgAl-LDH powder was heated from room temperature to 350°C at a heating rate of 1°C / min under the protection of an inert argon gas flow, and then continuously calcined at a constant temperature in an argon atmosphere for a period of time. After calcination, the sample was naturally cooled to room temperature under the protection of an argon atmosphere, and then sealed and stored for later use.

[0140] Prepare a chloroplatinic acid solution with a concentration of 0.25 mmol / L, and let it stand for later use.

[0141] Take 2g of the calcined hydrotalcite material and disperse it evenly in 50mL of chloroplatinic acid solution. Adjust the pH of the suspension to 8.5 using sodium hydroxide solution (0.5mol / L). Then, stir the suspension in a water bath at a certain temperature for 24h. After stirring, wash with deionized water until neutral, and dry for later use.

[0142] The material obtained above was heated to 500°C at a heating rate of 1°C / min and calcined in air for 4 hours.

[0143] The calcined powder was placed in a tube furnace and heated to 500°C at a constant heating rate in a 10 vol% H₂ / Ar atmosphere, followed by reduction for 2 hours. After reduction, the powder was cooled to room temperature under a 10 vol% H₂ / Ar atmosphere to obtain a Pt-based carbon monoxide oxidation catalyst, abbreviated as PtNi / MgAlO₂. x .

[0144] Characterization by ICP-OES revealed that the catalyst PtNi / MgAlO x Based on its total weight, the content of Mg as oxide is 37.15 wt%, the content of Al as oxide is 55.22 wt%, the content of Ni as oxide is 6.98 wt%, and the content of Pt as metal element is 0.65 wt%.

[0145] Characterization results from high-resolution annular dark-field scanning transmission electron microscopy (STEM-HAADF) and high-resolution transmission electron microscopy (HRTEM) revealed that the catalyst PtNi / MgAlO x Pt exists in the form of Pt-Ni alloy particles, and the average particle size of the Pt-Ni alloy particles is 8 nm.

[0146] The prepared catalyst PtNi / MgAlO x The reactor was placed in a fixed-bed microreactor with a reaction tube inner diameter of 6 mm. The temperature was increased to 250 °C at a rate of 5 °C / min and held constant. The reactant gas composition was 0.6 vol% CO / 0.005 vol% H₂S / 5 vol% O₂ / 94.395 vol% CO₂, and the reaction space velocity was controlled at 10000 h⁻¹. -1 The CO concentration at the reactor outlet was detected using gas chromatography. The results showed that during the 200-hour long-cycle carbon monoxide oxidation reaction, the carbon monoxide conversion rate remained above 99%.

[0147] Example 8

[0148] Dissolve 2.62g Co(NO3)2·6H2O, 3.84g Mg(NO3)2·6H2O, and 7.88g Al(NO3)3·9H2O completely in 150mL of deionized water, and label this solution A. Dissolve 12.75g Na2CO3 (0.8mol / L) and 6g NaOH (1.0mol / L) in 150mL of deionized water, and label this solution B. Add solutions A and B dropwise to a three-necked flask placed in a 65℃ water bath using a separatory funnel, while vigorously stirring the mixture. During the mixing process, maintain the pH of the mixed solution at 10.5 by adding NaOH solution (2.0mol / L) dropwise to ensure complete precipitation of the metal ions. After solutions A and B were mixed, the resulting mixture was stirred vigorously in a 65°C water bath for 24 hours. The precipitate was then washed with deionized water and dried in a forced-air drying oven for 12 hours. The resulting hydrotalcite sample was designated CoMgAl-LDH.

[0149] The CoMgAl-LDH powder obtained above was placed in the center of a quartz boat, and the quartz boat containing the sample was placed in the center of the heating section of the quartz tube in a tubular furnace. The CoMgAl-LDH powder was heated from room temperature to 300℃ at a heating rate of 1℃ / min under the protection of an inert argon gas flow, and then continuously calcined at a constant temperature in an argon atmosphere for a period of time. After calcination, the sample was naturally cooled to room temperature under the protection of an argon atmosphere, and then sealed and stored for later use.

[0150] Prepare a chloroplatinic acid solution with a concentration of 0.25 mmol / L, and let it stand for later use.

[0151] Take 2g of calcined hydrotalcite material and disperse it evenly in 55mL of chloroplatinic acid solution. Adjust the pH of the suspension to 6.0 using dilute hydrochloric acid solution (0.5mol / L). Then, stir the suspension in a water bath at a certain temperature for 24h. After stirring, wash with deionized water until neutral, and dry for later use.

[0152] The material obtained above was heated to 600°C at a heating rate of 3°C / min and calcined in air for 4 hours.

[0153] The calcined powder was placed in a tube furnace and heated to 500°C at a constant heating rate in a 10 vol% H₂ / Ar atmosphere, followed by reduction for 2 hours. After reduction, the powder was cooled to room temperature under a 10 vol% H₂ / Ar atmosphere to obtain a Pt-based carbon monoxide oxidation catalyst, abbreviated as PtCo / MgAlO₂. x .

[0154] ICP-OES analysis revealed that the catalyst PtCo / MgAlO xBased on its total weight, the content of Mg as oxide is 35.40 wt%, the content of Al as oxide is 59.72 wt%, the content of Co as oxide is 4.13 wt%, and the content of Pt as metal element is 0.75 wt%.

[0155] Characterization results from high-resolution annular dark-field scanning transmission electron microscopy (STEM-HAADF) and high-resolution transmission electron microscopy (HRTEM) revealed that the catalyst PtCo / MgAlO x Pt exists in the form of Pt-Co alloy particles, and the average particle size of the Pt-Co alloy particles is 4 nm.

[0156] The prepared catalyst PtCo / MgAlO x The reactor was placed in a fixed-bed microreactor with a reaction tube inner diameter of 6 mm. The temperature was increased to 250 °C at a rate of 5 °C / min and held constant. The reactant gas composition was 0.6 vol% CO / 0.005 vol% H₂S / 5 vol% O₂ / 94.395 vol% CO₂, and the reaction space velocity was controlled at 10000 h⁻¹. -1 The CO concentration at the reactor outlet was detected using gas chromatography. The results showed that during the 200-hour long-cycle carbon monoxide oxidation reaction, the carbon monoxide conversion rate remained above 99%.

[0157] Comparative Examples 1-3

[0158] The preparation methods of Comparative Examples 1, 2, and 3 correspond to those of Examples 1, 2, and 3, respectively. The methods for preparing the hydrotalcite support are the same, but the method for loading Pt differs from that in Examples 1-3. The platinum precursor chloroplatinic acid solution is directly loaded using an equal-volume impregnation method. The impregnation steps are briefly described below using Comparative Example 1 as an example:

[0159] Saturated water absorption rate determination: Weigh 1g of calcined FeMgAl-LDH support and add it to a 5mL graduated cylinder. After compacting it on a flat surface, the volume of the densely packed mixture is recorded as 0.8mL. Add 2mL of water, stir thoroughly, and let stand for 12h. The volume of the mixed liquid is recorded as 2.0mL. The saturated water absorption rate of the FeMgAl support is calculated to be 0.8mL / g.

[0160] Weigh 1.52 g of the prepared chloroplatinic acid solution and add it to a 50 mL beaker. Add 6.5 mL of deionized water and stir thoroughly to dissolve. Then, add 10 g of FeMgAl support and stir at room temperature for 0.5 h to obtain a slurry-like mixture. Seal the beaker containing the mixture with sealing film. Let it stand in a cool, dry place for 12 h.

[0161] The subsequent drying and roasting operations and conditions are the same as in the example.

[0162] Transmission electron microscopy (TEM) characterization revealed that the catalysts prepared in Comparative Examples 1-3 did not form uniformly sized small alloy particles. Taking the catalyst prepared in Comparative Example 1 as an example, its TEM characterization results are as follows: Figure 4 As shown, from Figure 4 It can be seen that the average particle size of the metal particles on the catalyst is 40 nm, which is much larger than that of the catalyst prepared in the above examples.

[0163] Table 1 shows a comparison of the reactivity evaluations of Examples 1-8 and Comparative Examples 1-3, where T50 and T90 refer to the lowest temperatures at which the conversion rate reaches 50% and 90%, respectively.

[0164] Table 1

[0165]

[0166]

[0167] As can be seen from the data in Table 1, the noble metal-based carbon monoxide oxidation catalyst described in this invention can still stably carry out the carbon monoxide oxidation and removal process in the presence of hydrogen sulfide, thus taking into account both catalytic oxidation activity and sulfur resistance reaction stability.

[0168] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing a noble metal-based carbon monoxide oxidation catalyst, characterized in that, The method includes the following steps: (1) Preparation of M-Mg-Al ternary hydrotalcite, wherein M is at least one of Fe, Co, Ni, Cu and Cr; (2) Calcining the M-Mg-Al ternary hydrotalcite; (3) The hydrotalcite material after calcination in step (2) is mixed with an aqueous solution of the precious metal precursor, and then the solid material is separated. (4) Calcine the solid material obtained in step (3); (5) Reduce the powder obtained after calcination in step (4); The specific operation process of step (3) is as follows: disperse the hydrotalcite material in the aqueous solution of the noble metal precursor, adjust the pH value of the obtained suspension to 5-9, stir in a constant temperature water bath for 5-48 hours, separate the solid and wash and dry it. The noble metal in the noble metal precursor is Pt and / or Pd, and Pt and / or Pd form alloy particles with M.

2. The method according to claim 1, characterized in that, In step (1), the M-Mg-Al ternary hydrotalcite is prepared by coprecipitation.

3. The method according to claim 2, characterized in that, The precipitant used is urea or a mixture of sodium carbonate and sodium hydroxide.

4. The method according to claim 2 or 3, characterized in that, The metal salt precursors used are nitrates and / or chlorides.

5. The method according to claim 4, characterized in that, The metal salt precursor used is nitrate.

6. The method according to claim 1, characterized in that, In step (2), the calcination conditions include: a temperature of 200-500℃ and a time of 3-6h.

7. The method according to claim 1, characterized in that, In step (3), the noble metal precursor is at least one of chloroplatinic acid, platinum chloride, platinum nitrate, platinum acetylacetonate, palladium chloride, palladium nitrate and palladium acetate.

8. The method according to claim 1 or 7, characterized in that, The temperature of the constant temperature water bath is 60-90℃.

9. The method according to claim 1, characterized in that, The specific operation of step (4) is as follows: the solid material is heated to 400-600℃ at a heating rate of 1-3℃ / min and calcined for 3-6 hours.

10. The method according to claim 1, characterized in that, In step (5), the reduction process is carried out in an atmosphere containing hydrogen and a protective gas, wherein the hydrogen content in the atmosphere containing hydrogen and a carrier gas is 8-15 vol.

11. The method according to claim 1 or 10, characterized in that, In step (5), the reduction conditions include: a temperature of 300-500℃ and a time of 1-3h.

12. A noble metal-based carbon monoxide oxidation catalyst prepared by the method according to any one of claims 1-11.

13. The noble metal-based carbon monoxide oxidation catalyst according to claim 12, comprising a support and an active component supported on the support, characterized in that, The active component is Pt and / or Pd, and the support is formed by calcination and reduction of M-Mg-Al ternary hydrotalcite, wherein M is at least one of Fe, Co, Ni, Cu and Cr, and Pt and / or Pd form alloy particles with M.

14. The noble metal-based carbon monoxide oxidation catalyst according to claim 12 or 13, characterized in that, Based on the total weight of the precious metal-based carbon monoxide oxidation catalyst, the content of Mg as oxide is 10-40% by weight, the content of Al as oxide is 20-60% by weight, the content of M as oxide is 0.5-10% by weight, and the content of Pt and / or Pd as metal elements is 0.1-1% by weight.

15. The use of the noble metal-based carbon monoxide oxidation catalyst according to any one of claims 12-14 as a catalyst for the carbon monoxide oxidation reaction.

16. The application according to claim 15, characterized in that, The reaction gas used in the carbon monoxide oxidation process contains less than 50 ppm of sulfides.

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