CN114423521A - Oxidation catalyst composition doped with manganese on a support - Google Patents

Oxidation catalyst composition doped with manganese on a support Download PDF

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CN114423521A
CN114423521A CN202080065429.2A CN202080065429A CN114423521A CN 114423521 A CN114423521 A CN 114423521A CN 202080065429 A CN202080065429 A CN 202080065429A CN 114423521 A CN114423521 A CN 114423521A
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support
catalyst
oxidation catalyst
alumina
manganese
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全俊红
金垠锡
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Heesung Catalysts Corp
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Heesung Catalysts Corp
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    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
    • B01J23/42—Platinum
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    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
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    • B01J23/56—Platinum group metals
    • B01J23/64—Platinum group metals with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
    • B01J23/656—Manganese, technetium or rhenium
    • B01J23/6562—Manganese
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    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • B01D53/9404—Removing only nitrogen compounds
    • B01D53/9409—Nitrogen oxides
    • B01D53/9413—Processes characterised by a specific catalyst
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    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • B01D53/944—Simultaneously removing carbon monoxide, hydrocarbons or carbon making use of oxidation catalysts
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    • B01J23/16—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
    • B01J23/32—Manganese, technetium or rhenium
    • B01J23/34—Manganese
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    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
    • B01J23/44—Palladium
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    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/0009—Use of binding agents; Moulding; Pressing; Powdering; Granulating; Addition of materials ameliorating the mechanical properties of the product catalyst
    • B01J37/0027—Powdering
    • B01J37/0036—Grinding
    • B—PERFORMING OPERATIONS; TRANSPORTING
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    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/0201—Impregnation
    • B—PERFORMING OPERATIONS; TRANSPORTING
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    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/0215—Coating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/08—Heat treatment
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F01N3/2066—Selective catalytic reduction [SCR]
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
    • F01N3/28—Construction of catalytic reactors
    • F01N3/2803—Construction of catalytic reactors characterised by structure, by material or by manufacturing of catalyst support
    • F01N3/2807—Metal other than sintered metal
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/10—Noble metals or compounds thereof
    • B01D2255/102—Platinum group metals
    • B01D2255/1021—Platinum
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • B01D2255/00—Catalysts
    • B01D2255/10—Noble metals or compounds thereof
    • B01D2255/102—Platinum group metals
    • B01D2255/1023—Palladium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/90—Physical characteristics of catalysts
    • B01D2255/915—Catalyst supported on particulate filters

Abstract

The present invention relates to an oxidation catalyst composition that can improve oxidation activity by doping manganese on a support, and more particularly, to a catalyst composition that can significantly improve oxidation activity by replacing a conventional activated alumina support with a modified support doped with manganese or a compound of manganese and cerium on a solid support, which can be suitably used for a catalyst structure such as a Diesel Oxidation Catalyst (DOC) or a Diesel Particulate Filter (DPF) by coating on the support.

Description

Oxidation catalyst composition doped with manganese on a support
Technical Field
The present invention relates to an oxidation catalyst composition that can improve oxidation activity by doping manganese on a support, and more particularly, to a catalyst composition that can significantly improve oxidation activity by replacing a conventional activated alumina support with a modified support doped with manganese or a compound of manganese and cerium on a solid support, which can be suitably used for a catalyst structure such as a Diesel Oxidation Catalyst (DOC) or a Diesel Particulate Filter (DPF) by coating on the support.
Background
Compression ignition diesel engines have advantages when used as a vehicle power source because of their inherently higher thermal efficiency at low speeds. However, since the diesel engine is operated under an extremely lean fuel condition, that is, a high air-fuel ratio (a/F) condition, the diesel engine emits less HC and CO than the gasoline engine, but at the same time, air pollution is induced by relatively large amounts of NOx and Particulate Matter (PM) being emitted.
As an aftertreatment means for improving the above-described problems, it is conceivable to use i) an oxidation catalyst (DOC) for purifying high boiling point hydrocarbons in the Particulate Matter (PM), ii) a denitrator (DeNOx) for decomposing or reducing NOx in an environment where oxygen is excessive, and iii) a particulate matter removing filter (DPF) for filtering the Particulate Matter (PM) with a filter.
Diesel vehicles are relatively good at HC and CO emissions, but in order to meet increasingly stringent regulatory requirements, it is necessary to install a filtration system, i.e. an oxidation catalyst (DOC), in a downstream natural regeneration mode that can remove HC and CO and remove highly active nitrogen oxides (NOx). During the process of the exhaust gas of the diesel engine passing through a Diesel Oxidation Catalyst (DOC), the diesel engine can be used in the environment of excess oxygenOxidation of CO and HC to CO2And H2O, but it is difficult to achieve high NOx conversion. NOx is to nitrogen monoxide (NO) and nitrogen dioxide (NO)2) Various types of nitrogen oxides are included to describe the terms used. Because higher NOx conversion is generally a requirement for rich reductant, it is difficult to effectively reduce NOx emissions in lean-burn engines such as diesel engines. To convert NOx constituents in the exhaust gas to harmless constituents, Selective Catalytic Reduction (SCR) of NOx is typically used under lean fuel conditions, which involves the reaction of NOx in the presence of a Selective Catalytic Reduction (SCR) catalyst, such as a vanadia-titania based catalyst or a reductant (e.g., urea) on a zeolite containing a base metal such as Cu, Fe or other base metals. Especially in the low temperature range (i.e. < 250 c) because of the appropriate proportion of NO in the gas when supplied to the Selective Catalytic Reduction (SCR) catalyst2Improved performance can be achieved in the presence of/NOx, and there is a need to achieve higher NO in a Diesel Oxidation Catalyst (DOC)2And (4) converting.
Reference is made to the prior art relating to Diesel Oxidation Catalysts (DOCs).
In a ceria-alumina oxidation catalyst and a method of using the same (registration No. 361419), an oxidation catalyst composition comprising, as catalyst components, platinum in an amount sufficient to promote oxidation of CO and HC (hydrocarbon) in a gas phase and palladium in an amount sufficient to have a certain surface area on ceria and alumina is disclosed. However, the conventional oxidation catalyst has a problem that its activity is gradually decreased with the lapse of time in an actual vehicle due to a decrease in specific surface area caused by deactivation factors of the catalyst, i.e., carbon deposition (carbon deactivation) and sulfur toxicity. An oxidation catalyst composition for a diesel engine (registered No. 279938) comprising a catalyst component comprising an activated alumina impregnated with 0.5 to 1.0 wt% of a platinum compound and having relatively large pores and a metal compound. Further, as the emission regulation requirements of diesel engines become increasingly strict, the content of platinum contained in a Diesel Oxidation Catalyst (DOC) is also rapidly increased and thus causes an increase in cost, and in order to solve the problems as described above, a method and a catalyst (registration No. 681334) in which a part of platinum may be replaced with palladium are disclosed.
Disclosure of Invention
Technical problem
In U.S. patent application No. 13/624,524, a diesel oxidation catalyst containing ceria as a palladium support substance is provided, and a Diesel Oxidation Catalyst (DOC) excellent in HC and CO performances is provided, but its NOx conversion rate is still low. Thus, an NO that can boost the exhaust gas emitted from a diesel engine is provided2A conversion Diesel Oxidation Catalyst (DOC) is preferred. To improve downstream NOx removal performance, especially to improve performance of downstream Selective Catalytic Reduction (SCR) catalysts, it is desirable to improve NO2Therefore, it is preferable to provide a diesel oxidation catalyst which can further lower the light-off temperature of HC and CO.
Technical scheme
The present invention relates to an oxidation catalyst composition for reducing exhaust gas discharged from a lean burn engine including a diesel engine, and particularly to an oxidation catalyst composition capable of lowering the light-off temperature of HC and CO and increasing the NOx conversion rate.
In a first embodiment, the present invention relates to an oxidation catalyst composition comprising a platinum-supporting solid support, wherein the solid support is doped with 1 to 5 wt.% of manganese, based on the total weight of the support.
In a second aspect, the present invention relates to an oxidation catalyst composition wherein said solid support is further doped with 20 wt.% or less of cerium.
In a third aspect, there is provided an oxidation catalyst composition wherein the solid support is a non-zeolitic material, i.e., alumina or activated alumina, silica-alumina, zirconia, or titania-alumina.
In a fourth aspect, there is provided an oxidation catalyst composition in which no noble metal other than platinum is supported on the solid support.
In the fifth embodiment, the oxidation catalyst composition may be applied to a catalyst structure of a Diesel Oxidation Catalyst (DOC) or a Diesel Particulate Filter (DPF) by coating on a carrier.
In a sixth embodiment, the Diesel Oxidation Catalyst (DOC) or the Diesel Particulate Filter (DPF) may further include a support in which 20 wt% or less (preferably 10 wt% or less) of a noble metal (preferably palladium) is supported on the noble metal of the catalyst structure, in addition to the oxidation catalyst composition of the first to fourth embodiments.
Detailed Description
According to one or more embodiments, the catalyst composition of the present invention may emit a greater amount of NO in order to enhance HC and CO oxidation performance and promote low temperature Selective Catalytic Reduction (SCR) reactions in a Selective Catalytic Reduction (SCR) catalyst located downstream of a diesel oxidation catalyst2。
The present inventors have identified that by doping the solid support with manganese, the oxidation activity of HC and CO can be improved and the NOx conversion can be increased, thereby producing an oxidation catalyst composition that can enhance downstream Selective Catalytic Reduction (SCR) reactions. Further, it was confirmed that the above-described characteristics can be further improved by doping the solid support with manganese and 20 wt% or less of cerium. In one or more embodiments applicable to the present invention, the oxidation catalyst composition is effective for reducing hydrocarbons and carbon monoxide in a lean burn engine exhaust gas stream and oxidizing NO to NO2。
Next, a description will be given of a conventional Diesel Oxidation Catalyst (DOC) catalyst composition, and the improved support of the present invention will be described. In the present specification, the catalyst composition refers to a composition in the form of a powder having a specific component supported on a support or in the form of a slurry containing other additives, and the catalyst structure refers to a structure in which the catalyst composition is applied to a general carrier such as a honeycomb substrate or a filter, and is also referred to as a catalyst product. It is well known that a vehicle aftertreatment catalyst system can be formed by combining catalyst articles as described above in series or in parallel. In the present specification, a catalyst may be understood as a catalyst composition or a catalyst structure depending on the context.
Diesel Oxidation Catalyst (DOC) catalyst compositions comprising a precious metal component such as platinum and/or palladium are suitable for use with high surface area refractory oxide supports such as high surface area alumina. The support is coated onto a monolithic (monolithic) support such as a refractory ceramic or metallic honeycomb structure. High surface area refractory metal oxides are used as supports for the catalytic components of a Diesel Oxidation Catalyst (DOC). For example, the BET (Brunauer, Emmett and Teller) surface area of a high surface area alumina species known as "gamma alumina" or "activated alumina" is typically 60 square meters per gram (m)2In the above, the activated alumina as described above is usually a gamma or delta phase (phase) mixture of alumina, but may contain equivalent eta, kappa and theta alumina phases. A method for producing a Diesel Oxidation Catalyst (DOC) catalyst composition containing platinum and palladium, which usually supports about 2:1 parts by weight of platinum and palladium, is known in the art.
The catalyst composition of the present invention is characterized in that a support not containing palladium and carrying platinum alone as a platinum group is applied, and the solid support is a modified support doped with manganese or manganese and cerium.
The solid support is a non-zeolitic material and may be alumina or activated alumina, silica-alumina, zirconia or titania-alumina and mixtures thereof, preferably alumina or silica-alumina.
The alumina is gamma alumina, and specifically can be gamma cubic alumina, gamma quasi-cubic alumina, gamma square alumina, gamma alumina that is hardly crystalline or has a low degree of crystallinity, gamma alumina with a large surface area, gamma alumina with a low surface area, gamma alumina produced from giant boehmite, gamma alumina produced from crystalline boehmite, gamma alumina produced from boehmite that is hardly crystalline or has a low degree of crystallinity, gamma alumina produced from a mixture of crystalline boehmite and an amorphous gel, gamma alumina produced from an amorphous gel, or gamma alumina that is delta-transferred.
The solid silica-alumina in the present invention is preferably silica-alumina having a silica content per unit mass of 5 to 95% by weight or less, preferably 10 to 80% by weight, more preferably 20 to 60% by weight, and still more preferably 30 to 50% by weight.
The Mn content doped into the solid support is in the range of 1 wt% (lower leading to a decrease in oxidation activity) to 20 wt% or less (higher leading to a decrease in NOx conversion) based on the weight of the doped support, preferably 10% or less. The doped manganese is derived from a soluble Mn species selected from Mn acetate, Mn nitrate, Mn sulfate, or combinations thereof. In another embodiment, Mn is derived from MnO, Mn2O3、MnO2And bulk Mn oxides selected from said combinations. Preferably, as Mn derived from soluble Mn species2O3The manganese salt may be impregnated into the support and then pre-calcined at 500 to 700 ℃ to form Mn2O3And (5) obtaining the form. As is well known to those skilled in the art, the step of impregnating the porous support with the manganese salt may be performed by a wet impregnation method or other known methods.
The inventors have determined that HC and CO in the exhaust gas stream of a lean burn engine can be more effectively reduced and NO oxidized to NO when manganese and cerium are doped together into a support2. In this case, the cerium may be derived from soluble Ce species or applicable bulk forms of cerium oxide. It is currently generally accepted in the industry that the inclusion of cerium in the support will be detrimental to NO2However, unlike the conventional concept described above, it was confirmed that when the cerium component is contained in a certain range, NO is rather favored2Is performed. The Ce content doped into the solid support is in the range of 1 to 20 wt% (higher leading to a decrease in NOx conversion) based on the weight of the support, preferably 10 wt%. The manganese and/or cerium may be present in the form of a solid solution together with the support, or may be dispersed as individual particles on the surface of the support.
It was preliminarily judged that manganese and/or cerium may contribute to the oxidation activity by the interaction with platinum supported on the support, but it was confirmed by various experiments from various angles that manganese and/or cerium does not exhibit an enhancing effect with platinum group elements other than platinum, but rather causes a problem of activity reduction. Therefore, the present invention is characterized in that the noble metal element supported on the modified support is only platinum. The content of the supported platinum component is 0.5 to 5 wt% based on the weight of the support, and the problem of the reduction of the oxidation activity is caused at or below the lower limit value, and the problem of the reduction of the NOx conversion rate is caused at or above the upper limit value.
The catalyst composition, which is a platinum-carrying modified support material to which the present invention is applied, is in the form of a coating (wash coat) composition, and the coating composition may further contain other additives such as a binder and a stabilizer. The stabilizer may be selected from alkaline earth metal components selected from the group consisting of magnesium, barium, calcium, and strontium. The coating composition is applied to a support or substrate (substrate), which may be, for example, a foam, web, or fluid form substrate. Preferably metallic or refractory ceramic, is a cordierite honeycomb structure extended by a plurality of parallel exhaust gas flow channels.
The catalyst composition to which the present invention is applied can be produced by changing a known method. First, a known Diesel Oxidation Catalyst (DOC) catalyst composition and a method for manufacturing a catalyst structure will be described. A slurry is prepared by mixing a solution of a noble metal compound, which is a platinum or palladium precursor, and a finely powdered high surface area support, such as gamma alumina. As described above, a binder and/or a stabilizer may be added to the slurry if necessary. Next, the slurry is pulverized by a ball mill or the like to adjust the solid matter substantially to a state of a particle size of less than 20 μm at a solid content of 20 to 80% by weight, and the obtained slurry is applied to a single sheet carrier.
< production of catalyst >
Next, a method for producing a Diesel Oxidation Catalyst (DOC) catalyst to which the modified support doped with manganese and cerium of the present invention is applied will be described.
Example 1: production of manganese-doped supports
The Mn-doped modified support was produced by adding a manganese nitrate solution to alumina powder (impregnated solid content: 67%) as a solid support by a wet impregnation method so as to contain 5 wt% of manganese oxide based on the weight of the final modified support, followed by drying (150 ℃/2h) and calcination at 500 ℃ or higher. It was confirmed that the state of the doped Mn oxide was Mn2O3。
Example 2: production of manganese-and cerium-doped supports
A Mn-Ce-doped modified support was produced by adding a manganese nitrate and cerium nitrate solution to alumina powder (67% of impregnated solid content) as a solid support by a wet impregnation method so as to contain 5 wt% of a manganese oxide and 10 wt% of ceria with respect to the weight of the final modified support, followed by drying (150 ℃/2h) and calcination (700 ℃/1h to 2 h). It was confirmed that the state of the doped Mn oxide was Mn2O3。
Example 3: production of Mn-only or Mn and Ce-doped catalysts
In the modified support powders obtained in examples 1 and 2, a catalyst composition having a Pt-supported modified support on which platinum was supported was prepared using chloroplatinic acid in a state in which the platinum component was 0.5, 1, 2, or 5 wt%, and was dispersed in water to prepare a slurry. The slurry is subjected to ball milling to make about 90% of the particles have a size of 8 to 10 μm. The ball-milled slurry is coated into a cordierite honeycomb structure. Drying at 150 to 160 c for about 10 minutes followed by calcination at 650 to 750 c for 10 hours produced Pt/5% Mn-alumina Diesel Oxidation Catalyst (DOC) catalyst (catalyst 1) and Pt/5% Mn-10% Ce-alumina Diesel Oxidation Catalyst (DOC) catalyst (catalyst 2).
Comparative example 1: production of Mn-undoped catalyst
A Pt/alumina Diesel Oxidation Catalyst (DOC) catalyst (comparative catalyst 1) was manufactured by performing as shown in example 3 using pure alumina powder as a support.
Test example 1:
tests of CO and HC light-off temperature (LOT) and NOx conversion rate were performed in an engine exhaust gas simulator for the manufactured Diesel Oxidation Catalyst (DOC) catalyst. The characteristics of the catalyst may be measured by light-off temperature (LOT), which is defined as a temperature at a point of time when the conversion efficiency of the catalyst exceeds 50%. The respective aging conditions are as follows.
Evaluation 1:
the results of the tests for catalyst 1(w/Mn) and comparative catalyst 1(w/o Mn) are shown in Table 1.
[ TABLE 1 ]
Figure BDA0003547156010000081
The light-off temperature (LOT) of catalyst 1 is lower than that of comparative catalyst 1 over all of the Pt loading content ranges given. Namely, the oxidation activity is improved. In addition, NO2the/NOx conversion rate is remarkably excellent compared to the comparative catalyst 1 in the case where the Pt content is 1 to 2. It can be confirmed from the X-ray diffraction (XRD) and Transmission Electron Microscope (TEM) measurements that the size of the Pt particles in the catalyst 1 is significantly reduced due to the interaction between Pt and Mn, and thus it can be judged that the Pt particles do not sinter but maintain a high degree of dispersion at high temperature, thereby improving the NO oxidation performance. Evaluation 2:
the CO light-off temperature (LOT) and NOx conversion test results for catalyst 1(w/Mn) and catalyst 2(w/Mn-Ce) are shown in Table 2. The aging conditions were the same as in table 1.
[ TABLE 2 ]
Figure BDA0003547156010000091
Although not limited to a specific theory, it is believed that the synergistic effect of Mn and Ce elements ultimately acts on the oxidation activity, although catalyst 2 unexpectedly exhibits superior oxidation activity to catalyst 1 in the present invention, although it is believed that the higher the cerium content, the more the formation of NO2 is hindered. In order to confirm an appropriate cerium content, catalysts were manufactured and tested while changing the cerium content of 10 wt% in example 2 to 15, 20 and 30 wt%, and the results are shown in table 3. This confirmed that up to 20 wt% was advantageous in terms of CO and THC oxidation activity, but NO was found to be advantageous in terms of NO2The content of (b) is preferably from a trace to 15%, more preferably 10% by weight.
[ TABLE 3 ]
Figure BDA0003547156010000092
The present invention has been described in detail with reference to specific embodiments, but the embodiments described above are only for illustrative purposes, and the scope of the present invention is defined by the appended claims.

Claims (7)

1. An oxidation catalyst composition characterized by:
as an oxidation catalyst composition comprising a platinum-loaded solid support doped with 1 to 5 wt.% manganese, based on the total weight of the support.
2. An oxidation catalyst composition according to claim 1, wherein:
the solid support is also doped with 1 to 20 wt.% cerium.
3. An oxidation catalyst composition according to claim 1, wherein:
the solid support is a non-zeolitic material, i.e., alumina or activated alumina, silica-alumina, zirconia, or titania-alumina.
4. An oxidation catalyst composition according to claim 1 to claim 3, characterized in that:
the solid support does not support a noble metal other than platinum.
5. A catalyst structure characterized in that:
coating an oxidation catalyst composition according to claim 1 to claim 3 onto a substrate.
6. The catalyst structure body according to claim 5, characterized in that:
the catalyst structure is a Diesel Oxidation Catalyst (DOC) or a Diesel Particulate Filter (DPF).
7. The catalyst structure body according to claim 5, characterized in that:
the catalyst structure body contains palladium in addition to platinum.
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103269775A (en) * 2010-12-21 2013-08-28 庄信万丰股份有限公司 Oxidation catalyst for a lean burn internal combustion engine
CN107405606A (en) * 2015-02-09 2017-11-28 巴斯夫公司 Diesel oxidation catalyst
CN107735161A (en) * 2015-03-03 2018-02-23 巴斯夫公司 NOxAdsorber catalyst, method and system
US20180318805A1 (en) * 2015-11-06 2018-11-08 Basf Corporation Diesel oxidation catalyst combining platinum group metal with base metal oxide
CN109590014A (en) * 2018-11-09 2019-04-09 四川大学 A kind of integral diesel tail gas oxidation catalyst and preparation method thereof

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100928868B1 (en) * 2007-03-28 2009-11-30 희성촉매 주식회사 DOC catalyst with improved diesel oxidation activity and sulfur resistance according to support doping
RU2018111984A (en) * 2015-09-04 2019-10-04 Басф Се INTEGRATED CATALIC AMMONIA AND SCR OXIDATION SYSTEMS
KR101716174B1 (en) * 2015-12-03 2017-03-14 희성촉매 주식회사 A catalyst composition for preventing white smoke output from diesel engine
WO2017205042A2 (en) * 2016-05-26 2017-11-30 Basf Corporation Core/shell catalyst particles and method of manufacture
GB201614677D0 (en) * 2016-08-30 2016-10-12 Johnson Matthey Plc Oxidation catalyst for a diesel engine exhaust

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103269775A (en) * 2010-12-21 2013-08-28 庄信万丰股份有限公司 Oxidation catalyst for a lean burn internal combustion engine
CN107405606A (en) * 2015-02-09 2017-11-28 巴斯夫公司 Diesel oxidation catalyst
CN107735161A (en) * 2015-03-03 2018-02-23 巴斯夫公司 NOxAdsorber catalyst, method and system
US20180318805A1 (en) * 2015-11-06 2018-11-08 Basf Corporation Diesel oxidation catalyst combining platinum group metal with base metal oxide
CN109590014A (en) * 2018-11-09 2019-04-09 四川大学 A kind of integral diesel tail gas oxidation catalyst and preparation method thereof

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
张小广等: "大气污染治理技术 新2版", 武汉理工大学出版社, pages: 187 *

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