A sulfur-resistant CO oxidation catalyst and its preparation method and application

Abstract

This invention relates to the field of nanocatalytic materials technology, and discloses a sulfur-resistant CO oxidation catalyst, its preparation method, and its application. The method includes: (1) contacting a platinum source with a substrate to be plated in the presence of a carrier gas to perform a first contact reaction, obtaining material I; (2) passivating material I with a modifier in the presence of a carrier gas to obtain a passivated material; (3) performing a second contact reaction with a second metal source to obtain material II; (4) performing a third contact reaction with a hydrazine-based reducing agent and calcining the product obtained after the third contact reaction to obtain the sulfur-resistant CO oxidation catalyst. The sulfur-resistant CO oxidation catalyst prepared by the method provided by this invention has high metal promoter dispersion, high catalytic conversion rate, low activation temperature, and exhibits excellent catalytic stability in a sulfur-containing atmosphere.

Description

Technical Field

[0001] This invention relates to the field of nanocatalytic materials technology, specifically to a sulfur-resistant CO oxidation catalyst, its preparation method, and its application. Background Technology

[0002] Carbon monoxide (CO) is a colorless, odorless, and toxic gas with a strong binding affinity to hemoglobin. High concentrations can cause varying degrees of poisoning symptoms, damaging the brain, heart, liver, kidneys, lungs, and other tissues, and even leading to death similar to electric shock. The minimum lethal concentration for human inhalation is 5000 ppm. CO mainly originates from the incomplete combustion or partial oxidation of coal, gasoline, and natural gas. Industrial furnaces, domestic boilers and stoves, as well as internal combustion engines and vehicle exhaust are the main sources of carbon monoxide pollution. With increasingly stringent environmental protection requirements, the state has successively imposed strict controls on the CO concentration in exhaust gases from chemical production facilities. Some regions have issued relevant standards specifying a maximum allowable CO emission of 200 mg / m³. 3 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, when the CO concentration in industrial waste gas exceeds 5 vol%, direct emission of the waste gas is not only a waste of resources but also causes serious environmental pollution. Therefore, methods such as cryogenic separation, solvent recovery, or solid adsorption separation are commonly used for CO purification, separation, and refinement. The purified gas has a very low CO content and can be directly discharged in compliance with standards. When the CO concentration in the tail gas is low (<20,000 ppm) (e.g., the desorbed gas from a low-temperature methanol washing unit used in acid gas removal in coal gasification plants), the recovery cost is high. To meet emission requirements, adsorption, photocatalysis, low-temperature plasma conversion, and combustion are commonly used to remove CO. Catalytic oxidation, which introduces a highly efficient catalyst to remove CO based on combustion, can reduce the temperature of the combustion process and has the advantages of simple process and high removal efficiency, thus attracting widespread attention.

[0004] In the development of highly efficient catalysts, scholars both domestically and internationally began research in the 1970s and subsequently obtained patents. Currently, there are three main types of catalysts used for the catalytic oxidation of CO: non-precious metal oxide catalysts, perovskite oxide catalysts, and precious metal catalysts.

[0005] Among the non-precious metal oxide catalysts used for low-temperature CO oxidation, the Hopcalite catalyst is the most important. It is a composite oxide catalyst with CuO-MnOx as its main component. This supportless catalyst can effectively remove CO at room temperature. The lattice oxygen on the catalyst surface directly participates in the reaction, reacting with CO molecules that are preferentially adsorbed and activated on the catalyst surface. The lattice oxygen vacancies caused by the reaction are replenished by the adsorption of oxygen from the air onto the catalyst surface, becoming lattice oxygen. The advantage of this catalyst is its low cost; the disadvantages are poor resistance to moisture and sulfur, and its susceptibility to deactivation.

[0006] Cobalt oxide, a non-precious metal oxide, also exhibits high low-temperature catalytic oxidation activity for CO. It typically uses cobalt nitrate as a precursor and sodium hydroxide as a precipitant, but sodium dodecyl sulfonate is required as a surfactant during preparation to achieve high low-temperature activity. Furthermore, the lowest temperature at which cobalt oxide catalysts prepared via precipitation oxidation can be used for CO catalytic oxidation is 98°C, and hydrogen peroxide needs to be added as an oxidant during the preparation process.

[0007] Perovskite oxide catalysts have been extensively reported for the catalytic oxidation of CO. CN1058357A discloses a perovskite-type rare earth composite oxide directly supported on a mullite-based carrier, which performs well at a CO concentration of 1% and a space velocity of 60,000 h⁻¹. -1 Under these conditions, the CO conversion rate reaches 99% at a reaction temperature of 250℃. This demonstrates that perovskite oxides generally require relatively high reaction temperatures for CO catalytic oxidation.

[0008] However, compared to non-precious metal catalysts, precious metal catalysts such as gold and palladium exhibit better activity and stability, but are more expensive. In recent years, attention has been paid to the synergistic effects between precious metals and certain transition metals to improve catalyst performance and thus reduce costs. However, the uneven distribution of the active components supported on these catalysts leads to low activity and unstable performance, thereby limiting their application areas.

[0009] The Pd-Ag / CeO2-ZrO2-Y2O3 catalyst disclosed in CN105312064A achieves a CO removal rate of 95% at 140℃, but it can only be used under low CO concentration conditions (200ppm). Furthermore, the preparation conditions are complex and involve many elements, which limits the application of this catalyst under industrial conditions.

[0010] The flower-shaped cerium oxide catalyst supported on gold nanoparticles disclosed in CN104857957A achieves a CO removal efficiency of 99% in the range of 25-60℃. However, its gold loading is only 1-4%, and the support is a micron-sized flower-shaped structure. The active component is gold nanoparticles, which are prone to agglomeration after the reaction, resulting in decreased activity and shortened lifespan, thus limiting its application.

[0011] Current research on CO catalytic oxidation removal is extensive. However, CO-containing waste gas from many chemical plants often contains low concentrations of sulfides (<50 ppm, including H2S, COS, etc.) due to the influence of preceding processes. The presence of sulfides can rapidly deactivate precious metal catalysts, hindering the catalytic removal process. Therefore, developing precious metal catalysts that simultaneously possess low activation temperatures, good sulfur resistance, and high stability has become an important direction for catalyst development. Summary of the Invention

[0012] The purpose of this invention is to overcome the problems of high activation temperature, poor stability, and poor sulfur resistance of existing catalysts used for CO catalytic oxidation.

[0013] To achieve the above objectives, a first aspect of the present invention provides a method for preparing a sulfur-resistant CO oxidation catalyst, the method comprising:

[0014] (1) In the presence of a carrier gas, a platinum source is brought into contact with the substrate to be plated to carry out a first contact reaction to obtain material I; the substrate to be plated is selected from at least one of nano Al2O3 carrier, nano SiO2, nano TiO2, and carbon nanotubes, and the volume average diameter of the substrate to be plated is 10nm-30nm.

[0015] (2) In the presence of a carrier gas, the modifier and the material I are passivated to obtain a passivated material;

[0016] (3) The passivation material is subjected to a second contact reaction with a second metal source to obtain material II; the second metal source contains at least one element selected from iron, nickel, cobalt and copper.

[0017] (4) A hydrazine-based reducing agent is reacted with material II in a third contact reaction, and the product obtained after the third contact reaction is calcined to obtain a sulfur-resistant CO oxidation catalyst.

[0018] The reaction conditions are controlled such that the content of platinum in the sulfur-resistant CO oxidation catalyst is 0.1-0.5 wt% by weight and the content of the second metal element is 1.5-3.5 wt% by weight.

[0019] The second aspect of the present invention provides a sulfur-resistant CO oxidation catalyst prepared by the method described in the first aspect above.

[0020] The third aspect of this invention provides the application of the sulfur-resistant CO oxidation catalyst described in the second aspect above in the removal of carbon monoxide from waste gas.

[0021] The sulfur-resistant CO oxidation catalyst provided by this invention exhibits excellent catalytic activity in the carbon monoxide oxidation reaction, with a low activation temperature, and also exhibits excellent catalytic stability in a sulfur-containing atmosphere.

[0022] This invention achieves precise control of the catalyst at the nanoscale through atomic layer deposition technology, forming an inert deposition layer around the active metal to prevent particle agglomeration during the reaction process. This results in a sulfur-resistant CO oxidation catalyst with high metal additive dispersion, low activation temperature, high stability, and high catalytic conversion rate. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a preferred structure for preparing a sulfur-resistant CO oxidation catalyst a1 provided by the present invention;

[0024] Figure 2 This is a curve showing the change in CO conversion rate of a preferred sulfur-resistant CO oxidation catalyst a1 provided by the present invention.

[0025] Explanation of reference numerals in the attached figures

[0026] Deposition 1: Second Contact Reaction Detailed Implementation

[0027] 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.

[0028] As previously stated, the first aspect of this invention provides a method for preparing a sulfur-resistant CO oxidation catalyst, the method comprising:

[0029] (1) In the presence of a carrier gas, a platinum source is brought into contact with the substrate to be plated to carry out a first contact reaction to obtain material I; the substrate to be plated is selected from at least one of nano Al2O3 carrier, nano SiO2, nano TiO2, and carbon nanotubes, and the volume average diameter of the substrate to be plated is 10nm-30nm.

[0030] (2) In the presence of a carrier gas, the modifier and the material I are passivated to obtain a passivated material;

[0031] (3) The passivation material is subjected to a second contact reaction with a second metal source to obtain material II; the second metal source contains at least one element selected from iron, nickel, cobalt and copper.

[0032] (4) A hydrazine-based reducing agent is reacted with material II in a third contact reaction, and the product obtained after the third contact reaction is calcined to obtain a sulfur-resistant CO oxidation catalyst.

[0033] The reaction conditions are controlled such that the content of platinum in the sulfur-resistant CO oxidation catalyst is 0.1-0.5 wt% by weight and the content of the second metal element is 1.5-3.5 wt% by weight.

[0034] Preferably, the second metal source is selected from at least one of organic compounds containing iron, organic compounds containing nickel, organic compounds containing cobalt, and organic compounds containing copper.

[0035] It should be noted that, in this invention, the weight content of the second metal element is the total weight content of iron, nickel, cobalt and copper in the sulfur-resistant CO oxidation catalyst.

[0036] Preferably, the second metal source is selected from at least one of Fe(C5H5)2, (C5H5)2Ni, bis(N,N'-di-isopropylacetamidine)cobalt, copper(II)bis(dimethylamino-2-propoxy), and copper acetylacetonate. The inventors have discovered that the sulfur-resistant CO oxidation catalyst prepared under this preferred condition can eliminate or modify ligand structures, forming inert adsorption sites to prevent the migration of active metals during the reaction; it can directionally anchor active substances, forming physical spatial isolation to avoid the aggregation of active species, effectively improving the dispersion of active metals, maximizing the contact interface between the metal and oxides, and thus resulting in higher catalytic efficiency.

[0037] Preferably, in this invention, the amounts of platinum and the second metal source are controlled such that the content of platinum in the obtained sulfur-resistant CO oxidation catalyst is 0.1-0.5 wt% by weight and the content of the second metal source is 1.5-3.5 wt% by weight.

[0038] Preferably, the volume ratio of the platinum source to the modifier is 30-50:1.

[0039] It should be noted that, in this invention, the volume ratio of the platinum source to the modifier refers to the ratio of the total volume of the platinum source introduced in the first contact reaction to the total volume of the modifier introduced in the passivation treatment.

[0040] In a preferred embodiment, in step (1), the operation of the first contact reaction includes performing 30-50 coating treatments I on the substrate to be coated using the platinum source. Preferably, in each of the coating treatments I, the volumetric flow rate of the platinum source is independently 70-180 sccm, and the ingress time of the platinum source relative to each 10g of the substrate to be coated is independently 3-20s.

[0041] In a preferred embodiment, the method of the present invention further includes: in step (2), before performing the passivation treatment, the material I is first purged with an inert gas and then applied to the passivation treatment.

[0042] Preferably, in step (2), the volumetric flow rate of the modifier is 70-180 sccm; and the introduction time of the modifier is 3-20 s relative to each 10 g of the substrate to be plated.

[0043] In a preferred embodiment, the volume ratio of the second metal source to the hydrazine reducing agent is 120-200:1.

[0044] It should be noted that, in this invention, the volume ratio of the second metal source to the hydrazine reducing agent refers to the ratio of the total volume of the second metal source introduced in the second contact reaction to the total volume of the hydrazine reducing agent introduced in the third contact reaction.

[0045] Preferably, in step (3), the second contact reaction includes performing 180-220 coating treatments on the passivation material using the second metal source. The inventors have found that in this preferred embodiment, the second metal can be precisely deposited on the platinum source surface, avoiding the second metal being loaded onto the support or other unreasonable adsorption sites, thus avoiding unnecessary side reactions and resulting in better catalytic sulfur resistance performance of the prepared sulfur-resistant CO oxidation catalyst.

[0046] Preferably, the volumetric flow rate of the second metal source is independently 70-180 sccm, and the introduction time of the second metal source is independently 20-50 s per 10 g of the substrate to be plated.

[0047] In a preferred embodiment, in step (4), the volumetric flow rate of the hydrazine reducing agent is 70-180 sccm; and the introduction time of the hydrazine reducing agent is 10-100 s relative to each 10 g of the substrate to be plated.

[0048] Preferably, the volumetric flow rate of the hydrazine reducing agent is 70-130 sccm; and the introduction time of the hydrazine reducing agent is 25-55 s relative to each 10 g of the substrate to be plated.

[0049] In a preferred embodiment, in step (1), the conditions for the first contact reaction are at least: a temperature of 150-250°C and a pressure of 80-200 Pa.

[0050] In a preferred embodiment, in step (2), the passivation treatment conditions shall at least satisfy the following: temperature of 150-250℃, pressure of 60-200Pa, and time of 10-45s.

[0051] Preferably, in step (3), the conditions for the second contact reaction are at least: temperature of 150-300℃ and pressure of 80-200Pa.

[0052] Preferably, the method of the present invention further includes, before carrying out the third contact reaction, post-treating the material II in an oxygen-containing atmosphere, and then carrying out the third contact reaction with the hydrazine reducing agent.

[0053] Preferably, the oxygen-containing atmosphere is a gas with an oxygen content of 5-10 vol%.

[0054] In a preferred embodiment, the post-processing conditions shall at least satisfy the following: temperature of 450-550℃, pressure of 80-200Pa, and time of 80-200s.

[0055] Preferably, in step (4), the conditions for the third contact reaction are at least: temperature of 120-350℃, pressure of 80-200Pa, and time of 80-200s.

[0056] In a preferred embodiment, in step (4), after the material II and the hydrazine reducing agent undergo the third contact reaction, the material II is purged with an inert gas to obtain the sulfur-resistant CO oxidation catalyst.

[0057] According to a preferred embodiment, the conditions for each of the two air-washing processes, namely air-washing I and air-washing II, are independently satisfied at least as follows: temperature 30-70°C, time 10-200s; and

[0058] The volumetric flow rate of the inert gas is 10-250 sccm relative to 10g of the substrate to be plated. The inventors have found that, under this preferred condition, the obtained sulfur-resistant CO oxidation catalyst exhibits better catalytic sulfur resistance.

[0059] More preferably, the inert gas is argon and / or helium.

[0060] In a preferred embodiment, in step (2), the modifier is selected from at least one of aromatic carboxylic acids, saturated carboxylic acids, xylene, and propylbenzene.

[0061] Preferably, in step (1), the platinum source is trimethyl(methylcyclopentadienyl)platinum(IV) and / or dimethyl(1,5-cyclooctadiene)platinum.

[0062] Preferably, in step (4), the hydrazine reducing agent has the structural formula R1R2N-NR3R4, wherein R1, R2, R3 and R4 are each independently selected from hydrogen and C1-C5 alkyl groups.

[0063] Preferably, the hydrazine reducing agent is selected from at least one of methylhydrazine, ethylhydrazine, propylhydrazine, tert-butylhydrazine, and anhydrous hydrazine.

[0064] According to a preferred embodiment, the method of the present invention further includes: the method is carried out in a reaction chamber connected to at least one ALD pulse valve; and in the presence of a carrier gas, the platinum source, the second metal source, the hydrazine reducing agent and / or the modifier are introduced into the reaction chamber through the pulse valve.

[0065] Preferably, the carrier gas is at least one of argon, helium, and nitrogen.

[0066] Preferably, the method of the present invention further includes: preheating the hydrazine reducing agent to 30-70°C before carrying out the third contact reaction.

[0067] Preferably, the method of the present invention further includes: preheating the platinum source and / or the second metal source to 140-180°C before introducing them into the reaction chamber.

[0068] According to a preferred embodiment, the operating temperature of the raw material transport pipeline and the ALD pulse valve in this invention is 180-200℃, and the pressure is 10-200Pa.

[0069] According to a preferred embodiment, the method of the present invention further includes: placing the substrate to be plated on a quartz plate in the reaction chamber, and after completing the second rinsing, calcining the obtained product in a muffle furnace under an air atmosphere at 445-455°C for 3.5-4.5 hours, and shaping it into a sphere with an average diameter of 3-5 mm by a ball rolling machine to obtain the sulfur-resistant CO oxidation catalyst.

[0070] It should be noted that the present invention does not have specific requirements for the ball rolling machine, and conventional models in the art can be used, as long as the average diameter of the ball meets the requirements of the present invention.

[0071] As previously stated, the second aspect of the present invention provides a sulfur-resistant CO oxidation catalyst prepared by the method described in the first aspect.

[0072] As mentioned above, the third aspect of the present invention provides the application of the sulfur-resistant CO oxidation catalyst described in the second aspect above in the removal of carbon monoxide from waste gas.

[0073] In this invention, unless otherwise specified, the ambient temperature or room temperature mentioned in the following examples is 25±3℃.

[0074] The present invention will be described in detail below through examples. Unless otherwise specified, the raw materials used are all commercially available products.

[0075] Base material I to be plated: is a nano-Al2O3 carrier with an average volume diameter of 20 nm;

[0076] Base material II to be plated: is nano-SiO2 with a volume average diameter of 15nm;

[0077] Base material III to be plated: is nano-TiO2 with an average volume diameter of 30 nm;

[0078] Base material IV to be coated: is carbon nanotubes with a volume average diameter of 15 nm;

[0079] Platinum source I: trimethyl(methylcyclopentadienyl)platinum(IV), purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., CAS No. 94442-22-5;

[0080] Platinum source II: dimethyl(1,5-cyclooctadiene)platinum, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., CAS number 12266-92-1;

[0081] Second metal source I: ferrocene (Fe(C5H5)2), purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., CAS number 102-54-5;

[0082] Second metal source II: Nickel dicene ((C5H5)2Ni), purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., CAS No. 1271-28-9;

[0083] Second metal source III: is bis(N,N'-di-iso-propylethamidinyl)cobalt, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., CAS number 635680-58-9;

[0084] Second metal source IV: Nickel acetylacetonate was purchased from Shanghai Maclean Biochemical Technology Co., Ltd., CAS No. 3264-82-2;

[0085] Hydrazine reducing agent: anhydrous hydrazine (H4N2), purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., CAS No. 302-01-2;

[0086] Modifier: xylene, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., CAS No. 1330-20-7;

[0087] Carrier gas: nitrogen;

[0088] Inert gas: Argon.

[0089] Ball rolling machine: Model ZLJ-800, disc diameter 80cm, disc edge height 120cm;

[0090] Gas chromatograph: Model GC-7890A, purchased from Agilent Technologies Shanghai Branch.

[0091] Unless otherwise specified, the operating temperature of the raw material transport pipeline and the ALD pulse valve in the following examples is 180°C and the pressure is 10Pa.

[0092] Furthermore, the conditions for both blow-wash I and blow-wash II are: temperature of 50°C and time of 100s.

[0093] Example 1

[0094] This embodiment illustrates a preferred method for preparing a sulfur-resistant CO oxidation catalyst provided by the present invention, which is carried out according to the following steps and with reference to the parameters in Table 1, specifically including:

[0095] (1) Place 10g of the substrate to be plated on the quartz plate in the reaction chamber, preheat the platinum source I to 150°C, open the ALD pulse valve of the platinum source, set the volume flow rate of the platinum source, and the introduction time is shown in Table 1. Use carrier gas to introduce the platinum source into the reaction chamber, and the temperature and pressure are shown in Table 1. Coating treatment I is carried out with the surface of the substrate to be plated. Coating treatment I is repeated 40 times to complete the first contact reaction and obtain material I.

[0096] (2) Use an inert gas to purge the material I, then open the ALD pulse valve of the modifier, set the volume flow rate and introduction time of the modifier as shown in Table 1, and the temperature and pressure as shown in Table 1. Use a carrier gas to introduce the modifier into the reaction chamber to passivate the material I. The passivation time is shown in Table 1, and a passivated material is obtained.

[0097] (3) Preheat the second metal source to 150°C, open the ALD pulse valve of the second metal source, set the volume flow rate of the second metal source, and the introduction time is shown in Table 1. Use carrier gas to introduce the second metal source into the reaction chamber, and the temperature and pressure are shown in Table 1. Perform coating treatment II on the surface of the passivation material. Repeat coating treatment II 200 times to complete the second contact reaction and obtain material II.

[0098] (4) Under an oxygen-containing atmosphere (oxygen content of 8 vol%) with pressure as shown in Table 1, the temperature was raised from room temperature to the temperature shown in Table 1 to perform post-treatment on material II. The post-treatment time is shown in Table 1.

[0099] Then, at the temperature and pressure shown in Table 1, the ALD pulse valve of the hydrazine reducing agent was opened, the volumetric flow rate of the hydrazine reducing agent was set, and the introduction time is shown in Table 1. The hydrazine reducing agent preheated to 70°C was subjected to a third contact reaction with the material III, and the contact reaction time is shown in Table 1.

[0100] Then, the product was purged with inert gas (II), scraped off the quartz plate, and calcined in a muffle furnace at 450°C in an air atmosphere for 4 hours. It was then shaped into spheres with an average diameter of 3.5 mm using a ball rolling machine to obtain the sulfur-resistant CO oxidation catalyst, named a1.

[0101] The elemental content of the sulfur-resistant CO oxidation catalyst is shown in Table 2.

[0102] Figure 1 This is a schematic diagram illustrating the structural changes during the preparation of the sulfur-resistant CO oxidation catalyst a1. Figure 1 First, platinum, an active metal, is introduced onto the substrate to be plated for coating treatment I to form material I; then, a modifier is introduced for passivation treatment, that is, a diaphragm is formed on the platinum surface to obtain a passivation material; then, a second metal element is deposited on the substrate to be plated for deposition 1 (coating treatment II); finally, the diaphragm is removed by post-treatment to obtain a sulfur-resistant CO oxidation catalyst.

[0103] Example 2

[0104] This embodiment is carried out using a similar method to Embodiment 1, except that: a second metal source II is used instead of a second metal source I for the second contact reaction, and the introduction time of the platinum source in each coating treatment I and the second metal source in coating treatment II is changed. For specific parameters, please refer to Table 1.

[0105] A sulfur-resistant CO oxidation catalyst was obtained and named a2;

[0106] The elemental content of the sulfur-resistant CO oxidation catalyst is shown in Table 2.

[0107] Example 3

[0108] This embodiment is carried out using a similar method to Embodiment 1, except that: the second metal source III with the same amount and volume is used instead of the second metal source I for the second contact reaction;

[0109] A sulfur-resistant CO oxidation catalyst was obtained and named a3;

[0110] The elemental content of the sulfur-resistant CO oxidation catalyst is shown in Table 2.

[0111] Example 4

[0112] This embodiment is carried out using a similar method to Embodiment 1, except that: an equal mass of substrate II to be plated is used instead of substrate I for the first contact reaction, platinum source II is used, and the parameter conditions are changed. See Table 1 for specific parameters.

[0113] The sulfur-resistant CO oxidation catalyst was obtained and named a4;

[0114] The elemental content of the sulfur-resistant CO oxidation catalyst is shown in Table 2.

[0115] Example 5

[0116] This embodiment is carried out using a similar method to Embodiment 1, except that: substrate III is used instead of substrate I for the first contact reaction to obtain the sulfur-resistant CO oxidation catalyst, named a5;

[0117] The elemental content of the sulfur-resistant CO oxidation catalyst is shown in Table 2.

[0118] Example 6

[0119] This embodiment is carried out using a similar method to Embodiment 1, except that: substrate IV is used instead of substrate I for the first contact reaction to obtain the sulfur-resistant CO oxidation catalyst, named a6;

[0120] The elemental content of the sulfur-resistant CO oxidation catalyst is shown in Table 2.

[0121] Example 7

[0122] This embodiment is carried out using a similar method to Example 1, except that: a second metal source IV is used instead of a second metal source I to carry out the second contact reaction, and the sulfur-resistant CO oxidation catalyst is obtained and named a7.

[0123] The elemental content of the sulfur-resistant CO oxidation catalyst is shown in Table 2.

[0124] Comparative Example 1

[0125] This comparative example uses the traditional equal-volume impregnation method to directly load a platinum precursor (chloroplatinic acid solution) onto a support to obtain a CO oxidation catalyst. Specific procedures include:

[0126] SS1. Weigh 0.1g of chloroplatinic acid (H2PtCl6) and add it to a 1L volumetric flask. Add deionized water to dissolve it completely, then bring the volume to 1L. After the solution is clear and uniform, let it stand to obtain a chloroplatinic acid solution.

[0127] SS2. The nano-Al2O3 support was placed in a muffle furnace and calcined at 500℃ in air atmosphere for 4 hours with a heating rate of 3℃ / min. After calcination, it was cooled to room temperature to obtain the treated nano-Al2O3 support, which was then sealed and stored.

[0128] SS3, Saturated water absorption rate determination: Weigh 1g (M0) of the treated nano Al2O3 carrier and add it to a 5mL graduated cylinder. After compacting it on a flat table, read the volume of the dense packing as 1mL (V1). Add 2mL (V2) of water, stir thoroughly, and let stand for 12h. Read the volume of the mixed liquid as 2.3mL (V3).

[0129] According to the formula: Carrier saturated water absorption rate ω=((V1+V2)-V3) / M0;(mL / g)

[0130] The saturated water absorption rate of the nano-Al2O3 support was calculated to be 0.7 mL / g.

[0131] SS4. Weigh 1.52g of the chloroplatinic acid solution prepared in step (1) and add it together with 1.16g of ferric nitrate (Fe(NO3)·9H2O) into a 50mL beaker. Add 6.3mL of deionized water and stir thoroughly to dissolve. Then, add 10g of the treated nano-Al2O3 support and stir at room temperature for 0.5h to obtain a slurry-like mixture. Seal the beaker containing the slurry-like mixture with a sealing film. Let it stand in a cool, dry place for 12h to obtain a slurry-like catalyst.

[0132] SS5. The slurry-like catalyst was placed in a crucible and then placed in a muffle furnace under air atmosphere. The temperature was increased from room temperature to 500℃ at a heating rate of 2℃ / min, and calcined at 500℃ for 4 hours. After calcination, the catalyst was cooled to room temperature, removed, sealed, and stored to obtain the CO oxidation catalyst, named DP1. The elemental content of the catalyst is shown in Table 2.

[0133] Comparative Example 2

[0134] This comparative example was carried out using a method similar to that of Comparative Example 1, except that in step SS4, the same mass (1.16 g) of nickel nitrate was used instead of iron nitrate to obtain a CO oxidation catalyst, named DP2.

[0135] The elemental content of the catalyst is shown in Table 2.

[0136] Comparative Example 3

[0137] This comparative example was carried out using a method similar to that of Comparative Example 1, except that in step SS4, cobalt nitrate of the same mass (1.16 g) was used instead of iron nitrate to obtain a CO oxidation catalyst, named DP3.

[0138] The elemental content of the catalyst is shown in Table 2.

[0139] Comparative Example 4

[0140] This comparative example was carried out using a method similar to that of Example 1, except that in step (1), the time for introducing the platinum source in each coating treatment I was 3s, and a CO oxidation catalyst was obtained, named DP4.

[0141] The elemental content of the catalyst is shown in Table 2.

[0142] Comparative Example 5

[0143] This comparative example was conducted using a method similar to that of Example 1, except that the modifier was introduced into the reaction chamber together with the platinum source in step (1) for a first contact reaction. Specifically, the operation of the first contact reaction included:

[0144] 10g of the substrate to be plated was placed on a quartz plate in the reaction chamber. The platinum source was preheated to 150°C. The ALD pulse valve of the platinum source was opened. The volumetric flow rate of the platinum source was set to 80 sccm and the introduction time was 5s. The volumetric flow rate of the modifier was set to 20 sccm and the introduction time was 5s. The platinum source and the modifier were introduced into the reaction chamber by carrier gas. The coating treatment I was carried out on the surface of the substrate to be plated at a temperature of 160°C and a pressure of 100Pa. The coating treatment I was repeated 40 times to complete the first contact reaction and obtain material I.

[0145] Then, material I is used instead of the passivation material in Example 1 and reacted with the second metal source in step (3) to obtain the CO oxidation catalyst, named DP5.

[0146] The elemental content of the catalyst is shown in Table 2.

[0147] Test Example 1

[0148] The catalyst prepared in the above example was placed in a fixed-bed microreactor (reaction tube inner diameter of 6 mm), and heated to 250 °C at a heating rate of 5 °C / min. The catalyst was then subjected to a catalytic oxidation reaction with the feed gas for 200 h.

[0149] The composition of the reactant gas was: 0.6 vol% CO (CO), 0.005 vol% H2S, 5 vol% O2, and 94.395 vol% CO2, with a reaction space velocity of 10000 h⁻¹. -1 .

[0150] The concentration of CO at the reactor outlet (Ct) was detected by gas chromatography at time t. t And calculate the CO conversion rate according to the following formula: CO conversion rate / % = (C0- C t ) / C0*100%;

[0151] Additionally, the activation temperature T 50 This refers to the temperature at which the CO conversion rate is 50%.

[0152] T 90 This refers to the temperature at which the CO conversion rate is 90%.

[0153] If the CO conversion rate of the catalyst still cannot reach 50% at 250℃, the catalytic oxidation reaction temperature will be further increased until the CO conversion rate of the catalyst reaches 50%, and this temperature will be recorded as T. 50 ';

[0154] If the CO conversion rate of the catalyst still cannot reach 90% at 250℃, the catalytic oxidation reaction temperature will be further increased until the CO conversion rate of the catalyst reaches 90%, and this temperature will be recorded as T. 90 ';

[0155] The CO conversion rate of product a1 was monitored over 200 hours. See the results below. Figure 2 ;

[0156] The CO conversion rate after 200 h of reaction was calculated for the catalysts prepared in the above examples, and the results are shown in Table 3.

[0157] Table 1

[0158]

[0159]

[0160] Table 2

[0161]

[0162] Table 3

[0163]

[0164] Table 3 (continued)

[0165]

[0166]

[0167] The reaction results show that the present invention achieves precise control of the catalyst at the nanoscale through atomic layer deposition technology, forming an inert deposition layer around the active metal to prevent particle agglomeration during the reaction process. This results in a sulfur-resistant CO oxidation catalyst with high metal additive dispersion, low activation temperature, high stability, and high catalytic conversion rate.

[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 sulfur-resistant CO oxidation catalyst, characterized in that, The method includes: (1) In the presence of a carrier gas, a platinum source is brought into contact with the substrate to be plated to carry out a first contact reaction to obtain material I; the substrate to be plated is selected from at least one of nano Al2O3 carrier, nano SiO2, nano TiO2, and carbon nanotubes, and the volume average diameter of the substrate to be plated is 10nm-30nm. (2) In the presence of a carrier gas, the modifier is passivated with the material I to obtain a passivated material; the modifier is selected from at least one of aromatic carboxylic acids, saturated carboxylic acids, xylene, and propylbenzene; (3) The passivation material is subjected to a second contact reaction with a second metal source to obtain material II; the second metal source contains at least one element selected from iron, nickel, cobalt and copper; (4) The hydrazine reducing agent is reacted with the material II in a third contact reaction, and the product obtained after the third contact reaction is calcined to obtain a sulfur-resistant CO oxidation catalyst; The reaction conditions are controlled such that the content of platinum in the sulfur-resistant CO oxidation catalyst is 0.1-0.5 wt% and the content of the second metal element is 1.5-3.5 wt%. The first contact reaction, the second contact reaction, and the third contact reaction are all carried out using atomic layer deposition technology.

2. The method according to claim 1, wherein, The second metal source is selected from at least one of Fe(C5H5)2, (C5H5)2Ni, bis(N,N'-di-isopropylacetamidine)cobalt, copper(II)bis(dimethylamino-2-propoxy), and copper acetylacetonate.

3. The method according to claim 1 or 2, wherein, The volume ratio of the platinum source to the modifier is 30-50:

1.

4. The method according to claim 1 or 2, wherein, In step (1), the operation of the first contact reaction includes: performing 30-50 coating treatments on the substrate to be coated using the platinum source.

5. The method according to claim 4, wherein, In each of the coating processes I, the volumetric flow rate of the platinum source is independently 70-180 sccm, and the ingress time of the platinum source is independently 3-20 s relative to each 10 g of the substrate to be coated.

6. The method according to claim 1 or 2, wherein, In step (2), the volumetric flow rate of the modifier is 70-180 sccm; and the introduction time of the modifier is 3-20 s relative to 10 g of the substrate to be plated.

7. The method according to claim 1 or 2, wherein, The volume ratio of the second metal source to the hydrazine reducing agent is 120-200:

1.

8. The method according to claim 1 or 2, wherein, In step (3), the operation of the second contact reaction includes: performing 180-220 coating treatments on the passivation material using the second metal source.

9. The method according to claim 8, wherein, The volumetric flow rate of the second metal source is independently 70-180 sccm, and the introduction time of the second metal source is independently 20-50 s per 10 g of the substrate to be plated.

10. The method according to claim 1 or 2, wherein, In step (4), the volumetric flow rate of the hydrazine reducing agent is 70-180 sccm; and the introduction time of the hydrazine reducing agent is 10-100 s relative to 10 g of the substrate to be plated.

11. The method according to claim 10, wherein, The volumetric flow rate of the hydrazine reducing agent is 70-130 sccm; and the introduction time of the hydrazine reducing agent is 25-55 s relative to each 10 g of the substrate to be plated.

12. The method according to claim 1 or 2, wherein, In step (1), the conditions for the first contact reaction must at least be: temperature of 150-250℃ and pressure of 80-200Pa.

13. The method according to claim 1 or 2, wherein, In step (2), the passivation treatment conditions must at least meet the following requirements: temperature of 150-250℃, pressure of 60-200Pa, and time of 10-45s.

14. The method according to claim 1 or 2, wherein, In step (3), the conditions for the second contact reaction must at least be: temperature of 150-300℃ and pressure of 80-200Pa.

15. The method according to claim 1 or 2, further comprising, before carrying out the third contact reaction, first post-treating the material II in an oxygen-containing atmosphere, and then carrying out the third contact reaction with the hydrazine reducing agent.

16. The method according to claim 15, wherein, The post-processing conditions must at least meet the following requirements: temperature 450-550℃, pressure 80-200Pa, and time 80-200s.

17. The method according to claim 1 or 2, wherein, In step (4), the conditions for the third contact reaction must at least be: temperature of 120-350℃, pressure of 80-200Pa, and time of 80-200s.

18. The method according to claim 1 or 2, wherein, In step (1), the platinum source is trimethyl (methylcyclopentadienyl)platinum (IV) and / or dimethyl (1,5-cyclooctadiene)platinum.

19. The method according to claim 1 or 2, wherein, In step (4), the hydrazine reducing agent has the structural formula R1R2N-NR3R4, wherein R1, R2, R3 and R4 are each independently selected from hydrogen and C1-C5 alkyl groups.

20. The method according to claim 1 or 2, wherein, In step (4), the hydrazine reducing agent is selected from at least one of methylhydrazine, ethylhydrazine, propylhydrazine, tert-butylhydrazine, and anhydrous hydrazine.

21. The sulfur-resistant CO oxidation catalyst prepared by the method according to any one of claims 1-20.

22. The application of the sulfur-resistant CO oxidation catalyst as described in claim 21 in the removal of carbon monoxide from waste gas.

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