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 method for preparing a sulfur-resistant CO oxidation catalyst. The method includes: (1) contacting a second metal source with a substrate to be plated in the presence of a carrier gas to carry out a first contact reaction to obtain material I; (2) carrying out a second contact reaction with a hydrazine-based reducing agent with material I to obtain material II; and (3) carrying out a third contact reaction with a platinum source with material II to obtain a 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 a simple preparation method. It also 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 plants. 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 catalytic CO 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] There is considerable research on the catalytic oxidation and removal of CO. However, many chemical plants' CO-containing waste gases often contain 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, making it impossible for the catalytic removal process to proceed smoothly.

[0012] Therefore, developing noble metal catalysts that can simultaneously achieve low activation temperature, good low-temperature activity, good sulfur resistance, simple preparation methods, and high stability has become an important direction for catalyst development. Summary of the Invention

[0013] The purpose of this invention is to overcome the problems of existing technologies for CO catalytic oxidation catalysts, such as high activation temperature, poor stability, complex preparation process, and poor sulfur resistance.

[0014] 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:

[0015] (1) In the presence of a carrier gas, a second metal source is brought into contact with the substrate to be plated to carry out a first contact reaction to obtain material I; the second metal source contains at least one element selected from iron, nickel, cobalt and copper; 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.

[0016] (2) A second contact reaction is carried out between a hydrazine-based reducing agent and material I to obtain material II;

[0017] (3) The material II is reacted with a platinum source in a third contact reaction 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% and the content of the second metal element is 1-5 wt%.

[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] The present invention prepares a sulfur-resistant CO oxidation catalyst through atomic layer deposition technology, which enhances the interaction between the second metal and the surface of the substrate to be plated, making it less likely to fall off during the CO removal reaction; and the platinum forms an interfacial alloy with the second metal, which can give full play to the electronic auxiliary role of the second metal, which is beneficial to the adsorption and conversion of CO, thereby improving the catalytic activity. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a preferred structure for preparing a sulfur-resistant CO oxidation catalyst b1 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 b1 provided by the present invention.

[0025] Explanation of reference numerals in the attached figures

[0026] Deposition 1: First contact reaction; Reduction: Second contact reaction

[0027] Deposition 2: Third contact reaction Detailed Implementation

[0028] 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.

[0029] As previously stated, the first aspect of this invention provides a method for preparing a sulfur-resistant CO oxidation catalyst, the method comprising:

[0030] (1) In the presence of a carrier gas, a second metal source is brought into contact with the substrate to be plated to carry out a first contact reaction to obtain material I; the second metal source contains at least one element selected from iron, nickel, cobalt and copper; 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.

[0031] (2) A second contact reaction is carried out between a hydrazine-based reducing agent and material I to obtain material II;

[0032] (3) The material II is reacted with a platinum source in a third contact reaction 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% and the content of the second metal element is 1-5 wt%.

[0034] 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.

[0035] The inventors discovered that the sulfur-resistant CO oxidation catalyst prepared under these preferred conditions can enhance the interaction between the second metal and the surface of the substrate to be plated, making it less likely to detach during the CO removal reaction; and the platinum forms an interfacial alloy with the second metal, which can fully utilize the electronic aid role of the second metal, which is beneficial to the adsorption and conversion of CO, thereby improving the catalytic activity.

[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.

[0037] Preferably, the volume ratio of the second metal source to the hydrazine reducing agent is 120-200:1.

[0038] 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 first contact reaction to the total volume of the hydrazine reducing agent introduced in the second contact reaction.

[0039] In a preferred embodiment, in step (1), the operation of the first contact reaction includes: performing 180-220 coating treatments on the substrate to be coated using the second metal source.

[0040] Preferably, in each of the coating processes I, 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 relative to each 10 g of the substrate to be coated.

[0041] In a preferred embodiment, the method further includes: in step (2), before carrying out the second contact reaction, rinsing the material I with an inert gas before applying it to the second contact reaction.

[0042] In a preferred embodiment, the method further includes: in step (2), after the material I is subjected to the second contact reaction with the hydrazine reducing agent, the material is then purged with an inert gas to obtain the material II.

[0043] 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

[0044] 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.

[0045] More preferably, the inert gas is argon and / or helium.

[0046] Preferably, the method of the present invention further includes: in step (3), the hydrazine reducing agent is preheated to 30-70°C before the second contact reaction is carried out.

[0047] Preferably, in step (3), the platinum source is trimethyl (methylcyclopentadienyl)platinum (IV) and / or dimethyl (1,5-cyclooctadiene)platinum.

[0048] Preferably, in step (3), the operation of the third contact reaction includes: performing 30-50 coating treatments on material II using the platinum source.

[0049] More preferably, in each of the coating processes II, 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.

[0050] In a preferred embodiment, in step (1), the conditions for the first contact reaction are at least: a temperature of 150-300°C and a pressure of 80-200Pa.

[0051] In a preferred embodiment, in step (2), the conditions for the second contact reaction are at least: temperature of 120-350°C, pressure of 80-200Pa, and time of 80-200s.

[0052] Preferably, in step (2), 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.

[0053] More preferably, the hydrazine reducing agent is selected from at least one of methylhydrazine, ethylhydrazine, propylhydrazine, tert-butylhydrazine, and anhydrous hydrazine.

[0054] 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.

[0055] In a preferred embodiment, in step (3), the conditions for the third contact reaction are at least: a temperature of 150-250°C and a pressure of 80-200Pa.

[0056] According to a preferred embodiment, the method of the present invention 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, and the hydrazine reducing agent are introduced into the reaction chamber through the pulse valve.

[0057] 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.

[0058] 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.

[0059] 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 third contact reaction, calcining the obtained product in a muffle furnace under an atmosphere of 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] In this invention, unless otherwise specified, the ambient temperature or room temperature mentioned in the following examples is 25±3℃.

[0064] The present invention will be described in detail below through examples. Unless otherwise specified, the raw materials used are all commercially available products.

[0065] Base material I to be plated: is a nano-Al2O3 carrier with an average volume diameter of 20 nm;

[0066] Base material II to be plated: is nano-SiO2 with a volume average diameter of 15nm;

[0067] Base material III to be plated: is a nano-Al2O3 carrier with an average volume diameter of 20 μm;

[0068] Platinum source I: trimethyl(methylcyclopentadienyl)platinum(IV), purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., CAS No. 94442-22-5;

[0069] Platinum source II: dimethyl(1,5-cyclooctadiene)platinum, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., CAS number 12266-92-1;

[0070] Second metal source I: ferrocene (Fe(C5H5)2), purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., CAS number 102-54-5;

[0071] Second metal source II: Nickel dicene ((C5H5)2Ni), purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., CAS No. 1271-28-9;

[0072] Second metal source III: Cobalt acetylacetonate (III), purchased from Shanghai Maclean Biochemical Technology Co., Ltd., CAS No. 21679-46-9;

[0073] Second metal source IV: Zinc acetylacetone, purchased from Shanghai Maclean Biochemical Technology Co., Ltd., CAS No. 14024-63-6;

[0074] Hydrazine reducing agent: anhydrous hydrazine (H4N2), purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., CAS No. 302-01-2;

[0075] Modifier: xylene, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., CAS No. 1330-20-7;

[0076] Carrier gas: nitrogen;

[0077] Inert gas: Argon.

[0078] Ball rolling machine: Model ZLJ-800, disc diameter 80cm, disc edge height 120cm;

[0079] Gas chromatograph: Model GC-7890A, purchased from Agilent Technologies Shanghai Branch.

[0080] 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.

[0081] Furthermore, the conditions for blow-washing I, blow-washing II, blow-washing III, and blow-washing IV are all: temperature of 50°C and time of 100s.

[0082] Example 1

[0083] This embodiment illustrates a preferred method for preparing a sulfur-resistant CO oxidation catalyst provided by the present invention, comprising the following steps:

[0084] (1) Place 10g of the substrate to be plated on the quartz plate in the reaction chamber, 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 onto the quartz plate in the reaction chamber, and the temperature and pressure are shown in Table 1. Perform coating treatment I with the surface of the substrate to be plated. Repeat coating treatment I 200 times to complete the first contact reaction and obtain material I.

[0085] (2) Use an inert gas to purge the material I; then open the ALD pulse valve of the hydrazine reducing agent, set the volume flow rate, inlet time, temperature and pressure of the hydrazine reducing agent as shown in Table 1, and carry out a second contact reaction with the purged material I using the hydrazine reducing agent preheated to 70°C. The second contact reaction time is shown in Table 1. Then purge the material II with an inert gas to obtain material II.

[0086] (3) Preheat the platinum source to 150°C, open the ALD pulse valve of the platinum source, set the volume flow rate, inlet time, temperature and pressure of the platinum source as shown in Table 1, introduce the platinum source into the quartz plate of the reaction chamber with the carrier gas and perform coating treatment II on the surface of material II, repeat coating treatment II 40 times to complete the third contact reaction, and obtain the sulfur-resistant CO oxidation catalyst, named b1.

[0087] The elemental content of the sulfur-resistant CO oxidation catalyst is shown in Table 2.

[0088] Figure 1 A schematic diagram of the structure for preparing sulfur-resistant CO oxidation catalyst b1 is shown. Figure 1 First, deposition 1 (first contact reaction) is performed on the substrate to be plated to deposit a second metal, resulting in material I; then, the second metal is reduced by a hydrazine reducing agent (second contact reaction) to obtain material II; finally, deposition 2 (third contact reaction) is performed to deposit platinum metal, resulting in a sulfur-resistant CO oxidation catalyst.

[0089] Example 2

[0090] This embodiment is carried out using a similar method to Embodiment 1, except that: substrate II is used instead of substrate I for the first contact reaction, platinum source II is used, the second metal source II is used, and the condition parameters are changed. See Table 1 for details. The sulfur-resistant CO oxidation catalyst is obtained and named b2.

[0091] The elemental content of the sulfur-resistant CO oxidation catalyst is shown in Table 2.

[0092] Example 3

[0093] This embodiment is carried out using a similar method to Embodiment 1, except that in step (1), the second metal source used is the second metal source III, and the sulfur-resistant CO oxidation catalyst is obtained and named b3;

[0094] The elemental content of the sulfur-resistant CO oxidation catalyst is shown in Table 2.

[0095] Example 4

[0096] This embodiment is carried out using a similar method to Embodiment 1, except that in step (2), the introduction time of the hydrazine reducing agent is reduced so that the volume ratio of the second metal source to the hydrazine reducing agent is 300:1, and the sulfur-resistant CO oxidation catalyst is obtained and named b4.

[0097] The elemental content of the sulfur-resistant CO oxidation catalyst is shown in Table 2.

[0098] Comparative Example 1

[0099] 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:

[0100] SS1. Weigh 0.1g of chloroplatinic acid (H2PtCl6) and add it to a 1L volumetric flask. Add deionized water to dissolve it completely, and then bring the volume to 1L. After the solution is cleared evenly, let it stand to obtain a chloroplatinic acid solution.

[0101] 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.

[0102] 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).

[0103] According to the formula: Carrier saturated water absorption rate ω = (V 1+ V 2 ）-V 3 ） / M 0 (mL / g)

[0104] The saturated water absorption rate of the nano-Al2O3 support was calculated to be 0.7 mL / g.

[0105] 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.

[0106] 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.

[0107] Comparative Example 2

[0108] This comparative example was conducted using a method similar to that of Example 1, except that the substrate III to be plated was used for the first contact reaction to obtain a CO oxidation catalyst, named DP2; the elemental content of the catalyst is shown in Table 2.

[0109] Comparative Example 3

[0110] This comparative example was carried out using a method similar to that of Example 1, except that in step (1), the second metal source used was the second metal source IV, and a CO oxidation catalyst was obtained, named DP3; the element content of the catalyst is shown in Table 2.

[0111] Test Example 1

[0112] 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.

[0113] The composition of the reaction feed gas is: 0.6 vol% CO ( C0), 0.005 vol% H2S, 5 vol% O2 and 94.395 vol% CO2, with a reaction space velocity of 10000 h⁻¹. -1 .

[0114] The concentration of CO at the reactor outlet was detected by gas chromatography at time t. C t And calculate the CO conversion rate according to the following formula: CO conversion rate / %=( C 0- C t ) / C 0 *100% ;

[0115] Additionally, the activation temperature T 50 This refers to the temperature at which the CO conversion rate is 50%.

[0116] T 90 This refers to the temperature at which the CO conversion rate is 90%.

[0117] The CO conversion rate of product b1 was monitored over 200 hours; the results are shown below. Figure 2 ;

[0118] 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.

[0119] Table 1

[0120]

[0121] Table 2

[0122]

[0123] Table 3

[0124]

[0125] The reaction results show that this invention achieves precise control of the catalyst at the nanoscale through atomic layer deposition technology, which enhances the interaction between the second metal and the support surface, and forms an interfacial alloy between the active metal and the second metal. This fully utilizes the electronic additive role of the second metal, which is beneficial to the adsorption and conversion of CO. This is a sulfur-resistant CO oxidation catalyst with low activation temperature, good low-temperature activity, high stability, and high catalytic conversion rate.

[0126] 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 second metal source is brought into contact with the substrate to be plated to carry out a first contact reaction to obtain material I; the second metal source contains at least one element selected from iron, nickel, cobalt and copper; 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) A second contact reaction is carried out between a hydrazine-based reducing agent and material I to obtain material II; (3) The material II is reacted with a platinum source in a third contact reaction 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 wt%. Platinum forms an interfacial alloy with the second metal; The first contact reaction, the second contact reaction, and the third contact reaction all employ atomic layer deposition (ALD) 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 second metal source to the hydrazine reducing agent is 120-200:

1.

4. The method according to claim 1 or 2, wherein, In step (1), the operation of the first contact reaction includes: performing 180-220 coating treatments on the substrate to be coated using the second metal source.

5. The method according to claim 4, wherein, In each of the coating processes I, 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 relative to each 10 g of the substrate to be coated.

6. The method according to claim 1 or 2, wherein, In step (3), the operation of the third contact reaction includes: performing 30-50 coating treatments on material II using the platinum source.

7. The method according to claim 6, wherein, In each of the coating processes II, 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.

8. 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 150-300℃ and pressure of 80-200Pa.

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

10. The method according to claim 1 or 2, wherein, In step (2), 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.

11. The method according to claim 1 or 2, wherein, The hydrazine reducing agent is selected from at least one of methylhydrazine, ethylhydrazine, propylhydrazine, tert-butylhydrazine, and anhydrous hydrazine.

12. The method according to claim 1 or 2, wherein, In step (3), the conditions for the third contact reaction must at least be: temperature of 150-250℃ and pressure of 80-200Pa.

13. The sulfur-resistant CO oxidation catalyst prepared by the method according to any one of claims 1-12.

14. The application of the sulfur-resistant CO oxidation catalyst according to claim 13 in the removal of carbon monoxide from waste gas.

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