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    • 专利摘要:
    diesel oxidation catalyst catalyst and catalyst composite, use and process for preparing the same and system for treating a gaseous exhaust stream from a diesel engine The present invention relates to a diesel oxidation catalyst layer (doc) comprising: a) a carrier substrate; b) a diesel oxidation catalytic material comprising b1) a first layer located on the carrier substrate, the first layer comprising palladium impregnated on a support material comprising ceria in an amount at least 45% by weight based on the total weight of the support material and optionally comprising platinum; b2) a second layer located on the first layer, the second layer comprising palladium and platinum, each impregnated with a support material comprising a metal oxide; wherein the weight ratio of platinum to palladium of the first layer is less than the weight ratio of platinum to palladium of the second layer.
    公开号:BR112014006900B1
    申请号:R112014006900-0
    申请日:2012-09-21
    公开日:2019-08-20
    发明作者:Gerd Grubert；Torsten Neubauer；Alfred Punke；Marcus Hilgendorff；Torsten Müller-Stach；Olga Gerlach；Xinyi Wei；Jeffrey Hoke；Shiang Sung；Stanley Roth
    申请人:Basf Se；Basf Corporation；
    IPC主号:
    专利说明:

    CATALYST AND DIESEL OXIDATION CATALYST COMPOSITE IN LAYERS, USE AND PROCESS FOR PREPARING THE SAME AND SYSTEM TO TREAT A GAS EXHAUST CHAIN OF A DIESEL ENGINE
    Technical field [0001] The present invention relates to a layered oxidation catalyst, in particular for the exhaust treatment of a diesel engine, containing ceria as palladium support material.
    Fundamentals [0002] Operation of poorly burning engines, for example, diesel engines and poorly burning gasoline engines, provides the user with excellent fuel economy and has very low emissions of gas hydrocarbons and carbon monoxide due to their operation in high air / fuel ratios under poor fuel conditions. Diesel engines, in particular, also offer significant advantages over gasoline engines in terms of their fuel economy, durability and their ability to generate high torque at low speed. From an emissions standpoint, however, diesel engines have more serious problems than their spark ignition equivalents.
    Emission problems refer to particulate matter (PM), nitrogen oxides (NOx), unburned hydrocarbons (HC) and carbon monoxide (CO). NOx is a term used to describe several chemical species of nitrogen oxides, including nitrogen monoxide (NO) and nitrogen dioxide (NO 2 ), among others.
    [0003] Oxidation catalysts comprising precious metals, such as platinum group metals (PGM) dispersed in a refractory metal oxide support, are known for use in the treatment of exhaust gases from diesel engines to convert both gaseous and hydrocarbon pollutants. carbon monoxide by catalyzing the oxidation of these pollutants to carbon dioxide and water. Such catalysts are
    2/30 usually contained in units called diesel oxidation catalysts (DOC), or more simply catalytic converters, which are placed in the exhaust flow path of a diesel engine to treat the exhaust before it ventures into the atmosphere. Typically, diesel oxidation catalysts are formed in ceramic or metallic substrate vehicles on which one or more catalyst coating compositions are deposited. In addition to the conversion of gaseous HC, CO and the soluble organic fraction (SOF) of particulate matter, oxidation catalysts containing platinum group metals dispersed in a refractory oxide support promote the oxidation of nitric oxide (NO) to nitric dioxide (NO 2 ).
    [0004] As is well known in the art, catalysts used to treat the exhaust of internal combustion engines are less effective during periods of operation at relatively low temperature, such as the initial cold start period of engine operation, because the exhaust engine temperature is not high enough for efficient catalytic conversion of harmful components in the exhaust. To that end, it is known in the art to include an adsorbent material, which can be a zeolite, as part of a catalytic treatment system to adsorb gaseous pollutants, usually hydrocarbons, and retain them during the initial cold start period. As the temperature of the exhaust gases increases, the adsorbed hydrocarbons are removed from the adsorbent and subjected to catalytic treatment at the highest temperature. In this regard, US5,125,231 discloses the use of platinum group metal doped zeolites as low temperature hydrocarbon adsorbents and also as oxidation catalysts.
    [0005] As discussed above, oxidation catalysts comprising a platinum group metal (PGM) dispersed in a refractory metal oxide support are known for use in the treatment of exhaust emissions from diesel engines. Platinum (Pt) continues
    3/30 being the most effective metal in the platinum group to oxidize CO and HC in a DOC, after aging at high temperature under poor conditions and in the presence of combustible sulfur. Nevertheless, one of the main advantages of using palladium (Pd) -based catalysts is the lower cost of 5 Pd compared to Pt. However, Pd-based DOCs typically show higher light-off temperatures for oxidation of CO and HC, especially when used with HC storage materials, potentially causing a delay in HC and or CO light-off. DOCs containing Pd can inhibit Pt activity to convert paraffins and / or oxidize NO and can also make the catalyst more susceptible to sulfur inhibition. These characteristics typically prevented the use of Pd as an oxidation catalyst in poor burn operations, especially for light diesel applications where engine temperatures remain below 250 ° C for most driving conditions. As 15 emissions regulations become more stringent, there is an ongoing goal to develop diesel oxidation catalyst (DOC) systems that provide improved performance, for example, light-off performance.
    [0006] WO2010 / 133309 discloses diesel oxidation catalysts 20 enriched with Pd and their application as catalysts for the oxidation of CO and HC emissions from a diesel engine / compression ignition.
    [0007] WO2010 / 083313 discloses a diesel oxidation catalyst comprising at least two, specifically three distinct layers, at least one of which contains an oxygen storage compound (OSC) which is present in a separate layer from most components platinum group metal (PGM), such as palladium and platinum.
    [0008] US2008 / 045405 discloses a diesel oxidation catalyst for the treatment of exhaust gas emissions, such as the oxidation of 30 unburned hydrocarbons and carbon monoxide, and the reduction of
    4/30 oxides of nitrogen. More particularly, US2008 / 045405 is directed to a thin coating composition comprising two distinct thin coating layers containing two distinctly different weight ratios of Pt: Pd.
    [0009] However, these state of the art DOCs still show unsatisfactory HC and CO permanence. Additionally, the hydrocarbon storage capacity of these state of the art DOCs is enhanced at the expense of the catalytic activity of the catalyst.
    [0010] Consequently, the present invention is directed to a diesel oxidation catalyst with a layered structure to maximize hydrocarbon storage capacity without sacrificing the catalytic activity of the catalyst. In addition, it was an objective of the present invention to provide a DOC that continuously supports the oxidation and reduction of unburned CO and HC and thus allows a minimum permanence of HC and CO. Finally, it was an objective of the present invention to provide a DOC which, due to the rarity and, consequently, the costs of precious metal components generally used for the preparation of DOCs, contains a reduced amount of platinum in the catalyst composition, allowing cost savings for DOC without reducing catalytic efficiency. There is also a goal of using other components of DOCs, for example zeolites, ceria and palladium, as efficiently as possible.
    Summary [0011] A layered diesel oxidation catalyst (DOC) comprising:
    a) a carrier substrate;
    b) a diesel oxidation catalytic material comprising b1) a first layer located on the carrier substrate, the first layer comprising palladium impregnated on a support material comprising ceria in an amount of at least 45% in i
    5/30 weight based on the total weight of the support material and optionally comprising platinum;
    b2) a second layer located on the first layer, the second layer comprising palladium and platinum, each impregnated in a support material comprising a metal oxide, in which the weight ratio of platinum to palladium in the first layer is less than the ratio weight from platinum to palladium of the second layer.
    [0012] Additionally provided is a process for the preparation of such a layered diesel oxidation catalyst comprising the steps of (i) providing a carrier substrate;
    (ii) optionally applying a subcoat layer to the vehicle substrate;
    (iii) applying a first layer to the carrier substrate or the subcoating layer, the first layer comprising palladium impregnated in a support material comprising ceria in an amount of at least 45% by weight based on the total weight of the support material and optionally comprising platinum;
    (iv) applying a second layer to the first layer, the second layer comprising palladium and platinum, each impregnated in a support material comprising a metal oxide, in which the weight ratio of platinum to palladium in the first layer is less than the platinum to palladium weight ratio of the second layer;
    (v) optionally applying a third layer to the second layer, the third layer comprising palladium impregnated in a support material comprising ceria in an amount of at least 45% by weight based on the total weight of the support material and optionally comprising platinum,
    6/30 wherein the weight ratio of platinum to palladium in the third layer is less than the weight ratio of platinum to palladium in the second layer.
    [0013] A system for treating a gaseous exhaust stream from a diesel engine is additionally provided, the system comprising:
    an exhaust conduit in fluid communication with the diesel engine via an exhaust manifold, the layered diesel oxidation catalyst as defined above, wherein the vehicle substrate is a wall flow substrate or a flow substrate through, and one or more of the following in fluid communication with the layered diesel oxidation catalyst composite: a catalytic soot filter (CSF), a selective catalytic reduction article (SCR), a catalytic reduction and storage article NOx (NSR).
    [0014] A method for treating a diesel exhaust stream is further provided, the method comprising contacting the exhaust flow with the layered diesel oxidation catalyst as defined above.
    Brief Description of the Figures [0015] Figure 1 shows light-off CO curves obtained from the diesel exhaust treatment using the DOCs according to Samples
    A), B), C), D) and E). The x-axis of the diagram indicated Catalyst Inlet T / ° C shows the respective catalyst inlet temperature in ° C and varies from 120 ° C to 280 ° C, while the y-axis indicated CO-Eff /% shows the corresponding effectiveness of oxidation of CO to CO 2 in% and varies from 0% to 100%. The values for Sample A) according to the invention are displayed in a solid line with markers, the values for Sample
    B) according to the invention are displayed on a dotted line, the values for Sample C) according to the invention are displayed on a dashed line, the values for Sample D) not according to
    7/30 invention are displayed on a solid line and the values for Sample E) not according to the invention are displayed on a solid line with crosses.
    [0016] Figure 2 shows HC light-off curves obtained from the 5 diesel exhaust treatment using the DOCs according to Samples
    A), B), C), D) and E). The x-axis of the diagram indicated Catalyst Inlet T / ° C shows the respective catalyst inlet temperature in ° C and varies from 120 ° C to 280 ° C, while the y-axis indicated HC-Eff /% shows the corresponding effectiveness of oxidation of HC to CO 2 in% and varies from 0% to 100%. The values for Sample A) according to the invention are displayed in a solid line with markers, the values for Sample
    B) according to the invention are displayed on a dotted line, the values for Sample C) according to the invention are displayed on a dashed line, the values for Sample D) not according to the invention are displayed on a solid line and the values for Sample E) not according to the invention are displayed in a solid line with crosses.
    [0017] Figure 3 shows HC and CO light-off temperatures at 50% conversion (CO) and 70% conversion (HC) obtained from the treatment of 20 diesel exhaust using DOCs according to Samples A), B C D E
    AND). The x-axis of the diagram shows the respective Samples from A) to E), while the y-axis indicated CO Light-off at 50% conversion / ° C and HC Light-off at 70% conversion / ° C shows the corresponding temperatures in which 50% of CO are oxidized to CO 2 and in which 70% of HC are oxidized to CO 2 , respectively and vary from 100 ° C to 260 ° C. The values for CO conversion are displayed as checkered bars and the values for HC conversion are displayed as dashed bars.
    Detailed Description [0018] The present invention relates to a layered diesel oxidation catalyst (DOC) comprising:
    8/30
    a) a carrier substrate;
    b) a diesel oxidation catalytic material comprising b1) a first layer located on the carrier substrate, the first layer comprising palladium impregnated on a support material comprising ceria in an amount of at least 45% by weight based on the total weight of the support material and optionally comprising platinum;
    b2) a second layer located on the first layer, the second layer comprising palladium and platinum, each impregnated in a support material comprising a metal oxide, in which the weight ratio of platinum to palladium in the first layer is less than the ratio weight from platinum to palladium of the second layer.
    [0019] Generally, there are no specific restrictions with respect to the weight ratio of platinum to palladium of the first layer, provided that the weight ratio of platinum to palladium of the first layer is less than the weight ratio of platinum to palladium of the second layer. Preferably, the weight ratio of platinum to palladium of the first layer is in the range of 0: 1 to 1.1: 1.
    [0020] Therefore, the present invention also relates to the diesel oxidation catalyst as defined above, wherein the weight ratio of platinum to palladium of the first layer is in the range of 0: 1 to 1.1: 1.
    [0021] Likewise, there are no specific restrictions with regard to the weight ratio of platinum to palladium of the second layer, provided that the weight ratio of platinum to palladium of the first layer is less than the weight ratio of platinum for palladium of the second layer. Preferably, the weight ratio of platinum to palladium of the second layer is in the range of 1: 0 to 1.1: 1, more preferably in the range of 10: 1 to 1.5: 1, even more preferably in the range of 5: 1 to 2: 1, more preferably in a 2: 1 ratio, provided that the weight ratio of
    9/30 platinum to palladium of the first layer is less than the weight ratio of platinum to palladium of the second layer.
    [0022] Therefore, the present invention also relates to the diesel oxidation catalyst as defined above, in which the weight ratio of platinum to palladium of the second layer is in the range of 1: 0 to 1.1: 1, preferably in the 10: 1 to 1.5: 1 range, most preferably in the 5: 1 to 2: 1 range, more preferably in the 2: 1 range.
    [0023] According to the present invention, the weight ratio of platinum to palladium of the first layer is less than the weight ratio of platinum to palladium of the second layer. Preferably, the ratio of the platinum to palladium weight ratio of the first layer to the platinum to palladium weight ratio of the second layer is less than or equal to 0.9.
    [0024] Therefore, the present invention also relates to the diesel oxidation catalyst as defined above, wherein the ratio of the weight ratio of platinum to palladium of the first layer to the weight ratio of platinum to palladium of the second layer is lower or equal to 0.9.
    [0025] According to the present invention, the first layer comprises palladium impregnated in a support material comprising ceria in an amount of at least 45% by weight based on the total weight of the support material. Preferably, the first layer support material comprises ceria in an amount of at least 65% by weight, more preferably at least 85% by weight, even more preferably at least 95% by weight, more preferably 100% by weight based on total weight of support material.
    [0026] Therefore, the present invention relates to the diesel oxidation catalyst as defined above, wherein the support material of the first layer comprises ceria in an amount of at least 65% by weight, preferably at least 85% by weight, more preferably at least 95% by weight, more preferably 100% by weight based on the total weight of the support material.
    !
    10/30 [0027] Preferably, the support material of the first layer additionally comprises zirconia and / or alumina.
    [0028] Therefore, the present invention relates to the diesel oxidation catalyst as defined above, wherein the support material of the first layer additionally comprises zirconia or alumina.
    [0029] Preferably, the support material of the first layer comprises a modifier selected from the group consisting of La 2 O 3 , PreOn, HfO 2 , Y 2 O 3 , Yb 2 O 3 , YbO, Nd 2 O 3 , NdO, WO 3 , SiO 2 , TiO 2 and combinations of two or more of the same.
    [0030] Therefore, the present invention relates to the diesel oxidation catalyst as defined above, in which the support material of the first layer additionally comprises a modifier selected from the group consisting of La 2 O 3 , ΡΓθΟ ^, HfO 2 , Y 2 O 3 , Yb 2 O 3 , YbO, Nd 2 O 3 , NdO, WO 3 , SiO 2 , TiO 2 and combinations of two or more of the same.
    [0031] More preferably, the support material of the first layer comprises a ceria-zirconia material consisting of CeO 2 : 45% by weight, ZrO 2 : 43.5% by weight, La 2 O 3 : 8% by weight, Pr 6 On: 2% by weight and HfO 2 : 1.5% by weight.
    [0032] According to the present invention, the support material of the second layer may comprise a metal oxide. Preferably, the support material of the second layer comprises a metal oxide selected from the group consisting of alumina, zirconia, silica, titania, silica-alumina, alumina-zirconia, titania-silica, titania-zirconia, titaniaalumina and combinations of two or more of them.
    [0033] Therefore, the present invention relates to the diesel oxidation catalyst as defined above, in which the support material of the second layer comprises a metal oxide selected from the group consisting of alumina, zirconia, silica, titania, silica- alumina, alumina-zirconia, titania-silica, titania-zirconia, titania-alumina and combinations of two or more of the same.
    I
    According to the present invention, it is additionally preferred that the metal oxide of the second layer comprises alumina, more preferably gamma alumina or activated alumina, such as gamma or eta alumina. Preferably, the activated alumina has a specific surface area, determined according to the BET surface area measurements, from 60 to 300 m 2 / g, preferably from 90 to 200 m 2 / g, more preferably from 100 to 180 m 2 / g.
    [0035] It is more preferred that the second layer has a ceria content of not more than 5% by weight, preferably not more than 1% by weight, more preferably not more than 0.1% by weight.
    [0036] Therefore, the present invention relates to the diesel oxidation catalyst as defined above, wherein the second layer has a ceria content of not more than 5% by weight, preferably not more than 1% by weight, more preferably not more than 0.1% by weight.
    [0037] Generally, there are no specific restrictions regarding the palladium content of the first layer, provided that the weight ratio of platinum to palladium of the first layer is less than the weight ratio of platinum to palladium of the second layer. Preferably, the first layer comprises palladium in an amount of 6 to 60 g / ft 3 .
    [0038] Therefore, the present invention relates to the diesel oxidation catalyst as defined above, wherein the first layer comprises palladium in an amount of 6 to 60 g / ft 3 .
    [0039] Generally, there are no specific restrictions regarding the platinum content of the first layer, provided that the weight ratio of platinum to palladium of the first layer is less than the weight ratio of platinum to palladium of the second layer. Preferably, the first layer comprises platinum in an amount of 15 to 40 g / ft 3 .
    12/30 [0040] Therefore, the present invention relates to the diesel oxidation catalyst as defined above, wherein the first layer comprises platinum in an amount of 15 to 40 g / ft 3 .
    [0041] Generally, there are no specific restrictions with regard to the total platinum and palladium content of the second layer, provided that the weight ratio of platinum to palladium of the first layer is less than the weight ratio of platinum to palladium of the second layer. Preferably, the second layer comprises platinum and palladium in a total amount of 30 to 180 g / ft 3 .
    [0042] Therefore, the present invention relates to the diesel oxidation catalyst as defined above, wherein the second layer comprises platinum and palladium in a total amount of 30 to 180 g / ft 3 .
    [0043] Although there are no specific restrictions regarding the total amount of catalytic oxidation material for diesel, provided that the weight ratio of platinum to palladium in the first layer is less than the weight ratio of platinum to palladium in the second layer, it is preferable that the diesel oxidation catalytic material comprises platinum and palladium in a total amount of 30 to 240 g / ft 3 .
    [0044] Therefore, the present invention relates to the diesel oxidation catalyst as defined above, wherein the diesel oxidation catalytic material comprises platinum and palladium in a total amount of 30 to 240 g / ft 3 .
    [0045] Preferably, the second layer additionally comprises a hydrocarbon storage compound, preferably a zeolite. If present, the second layer comprises the hydrocarbon storage compound in a total amount of 0.1 to 1 g / foot 3 , preferably 0.3 to 0.8 g / foot 3 , more preferably in an amount of 0, 5 g / foot 3 .
    [0046] Therefore, the present invention relates to the diesel oxidation catalyst as defined above, wherein the second layer
    I
    13/30 further comprises a hydrocarbon storage compound, preferably a zeolite.
    [0047] Typically, any types of zeolite / aluminosilicate structure can be used, such as types of ABW, ACO, AEI, AEL, AEN, AET, AFG.AFI, AFN, AFO, AFR, AFS, AFT, AFX, AFY , AHT, ANA, APC, APD, AST, ASV, ATN, ATO, ATS, ATT, ATV, AWO, AWW, BCT, BEA, ΒΕΟ, ΒΙΚ, BOG, BPH, BRE, CAN, CAS, SCO, CFI, SGF , CGS, CHA, CHI, CLO, CON, CZP, DAC, DDR, DFO, DFT, DOH, DON, EAB, EDI, EMT, EON, EPI, ERI, ESV, ETR, EUO, FAU, FER, FRA, GIS , GIU, GME, GON, GOO, HEU, IFR, IHW, ISV, ITE, ITH, ITW, IWR, IWW, JBW, KFI, LAU, LEV, LIO, LIT, LOS, LOV, LTA, LTL, LTN, MAR , MAZ, MEI, HONEY, MEP, MER, MFI, MFS, MON, MOR, MOZ, MSO, MTF, MTN, MTT, MTW, MWW, NAB, NAT, NES, NON, NPO, NSI, OBW, OFF, OSI , OSO, OWE, PAR, PAU, PHI, PON, RHO, RON, RRO, RSN, RTE, RTH, RUT, RWR, RWY, SAO, SAS, SAT, SAV, SBE, SBS, SBT, SFE, SFF, SFG , SFH, SFN, SFO, SGT, SOD, SOS, SSY, STF, STI, STT, TER, THO, TON, TSC, UEI, UFI, UOZ, USI, UTL, VET, VFI, VNI, VSV, WIE, WEN , YUG, ZON or a mixture of one or more of them.
    [0048] The zeolite can be a natural or synthetic zeolite, such as faujasite, chabazite, clinoptilolite, mordenite, silicalite, zeolite X, zeolite Y, ultra-stable Y zeolite, zeolite ZSM-5, zeolite ZSM-12, zeolite SSZ-3, zeolite SSZ-3, SAPO 5, offretite or a beta zeolite. Preferred zeolite materials have a high ratio of silica to alumina. Zeolites can have a silica: alumina molar ratio of at least 25: 1, preferably at least 50: 1, with useful ranges from 25: 1 to 1000: 1, 50: 1 to 500: 1 as well as 25: 1 to 300: 1, from 100: 1 to 250: 1, or alternatively from 35: 1 to 180: 1 is also exemplified. Preferred zeolites include ZSM, Y and beta zeolites. A particularly preferred beta zeolite is of the type disclosed in US6,171,556. The zeolite can be present in its Form H and / or its Form Na. In addition, zeolite can be doped with metal.
    It is more preferred that the diesel oxidation catalyst additionally comprises a subcoat layer located between the carrier substrate and the first layer, the subcoat layer preferably comprising alumina, more preferably the alumina range.
    [0050] Therefore, the present invention relates to the diesel oxidation catalyst as defined above further comprising an undercoat layer located between the carrier substrate and the first layer, the undercoat layer preferably comprising alumina, more preferably gamma alumina.
    [0051] In accordance with the present invention, the carrier substrate can be a pass-through substrate or a wall flow substrate.
    [0052] Therefore, the present invention relates to the diesel oxidation catalyst as defined above, wherein the carrier substrate is a through-flow substrate or a wall-flow substrate.
    [0053] Wall flow substrates useful for the diesel oxidation catalysts of the present invention have a plurality of substantially parallel thin flow passages extending along the longitudinal axis of the substrate. Each passage is blocked at one end of the substrate body, with alternative passages blocked at opposite end faces. These monolithic vehicles can contain up to about 400 flow passages (or cells) per square inch (2.54 cm) 2 ) in cross section, although many less can be used. For example, the vehicle can have 7 to 400, preferably 100 to 400, cells per square inch (cpsi). The cells can have cross sections that are rectangular, square, circular, oval, triangular, hexagonal, or are of other polygonal shapes.
    [0054] Preferred wall flow substrates are composed of ceramic-like materials, such as cordierite, alpha-alumina,
    15/30 silicon carbide, silicon nitride, zirconia, mullite, spodumene, silica alumina-magnesia-silicate or zirconium; or refractory metals, such as stainless steel. Preferred wall flow substrates are formed from cordierite and silicon carbide. Such materials are able to withstand the environment, particularly high temperatures, encountered when treating exhaust currents. Ceramic wall flow substrates are typically formed of a material having a porosity of about 40 to 70. The term porosity, as used in this context, is understood to be determined according to a porosity measurement of 10 mercury according to DIN 66133 In accordance with the present invention, wall flow substrates are preferred having a porosity in the range of 38 to 75.
    [0055] It is additionally preferred that the carrier substrate comprises a material selected from the group consisting of 15 cordierite, cordierite-alumina, silicon nitride, silicon carbide, zirconium mullite, spodumene, alumina-silica magnesia, zirconium silicate , silimanite, magnesium silicate, zirconium, petalite, alumina, aluminosilicate and combinations of two or more of the same.
    [0056] Therefore, the present invention relates to the diesel oxidation catalyst as defined above, in which the carrier substrate comprises a material selected from the group consisting of cordierite, cordierite-alumina, silicon nitride, silicon carbide, zirconium mullite, spodumene, alumina-silica magnesia, zirconium silicate, silimanite, magnesium silicate, zirconium, petalite, alumina, aluminosilicate and 25 combinations of two or more of the same.
    [0057] Generally, there are no specific restrictions on the number of layers of the layered diesel oxidation catalyst. With the proviso that the diesel oxidation catalytic material comprises at least
    16/30 b1) a first layer located on the carrier substrate, the first layer comprising palladium impregnated in a support material comprising ceria in an amount of at least 45% by weight based on the total weight of the support material and optionally comprising platinum; and b2) a second layer located on the first layer, the second layer comprising palladium and platinum, each impregnated in a support material comprising a metal oxide, in which the weight ratio of platinum to palladium of the first layer is less than that weight ratio of platinum to palladium of the second layer, the number of layers of the layered diesel oxidation catalyst can be varied. Preferably, the layered diesel oxidation catalyst further comprises b3) a third layer located on the second layer, the third layer comprising palladium impregnated on a support material comprising ceria in an amount of at least 45% by weight based on the total weight of the support material and optionally comprising platinum;
    wherein the weight ratio of platinum to palladium of the third layer is less than the weight ratio of platinum to palladium of the second layer.
    [0058] Therefore, the present invention relates to the diesel oxidation catalyst as defined above further comprising b3) a third layer located on the second layer, the third layer comprising palladium impregnated on a support material comprising ceria in an amount of at least 45 % by weight based on the total weight of the support material and optionally comprising platinum, where the weight ratio of platinum to palladium of the third layer is less than the weight ratio of platinum to palladium of the second layer.
    [0059] According to the present invention, if a third layer is present, the weight ratio of platinum to palladium of the third layer will be less than the weight ratio of platinum to palladium of the second layer. Preferably, the ratio of the weight ratio of platinum to palladium of the third layer to the weight ratio of platinum to palladium of the second layer is less than or equal to 0.9.
    [0060] Therefore, the present invention also relates to the diesel oxidation catalyst as defined above, wherein the ratio of the weight ratio of platinum to palladium of the third layer to the weight ratio of platinum to palladium of the second layer is lower or equal to 0.9.
    [0061] According to the present invention, if a third layer is present, the third layer will comprise palladium impregnated in a support material comprising ceria in an amount of at least 45% by weight based on the total weight of the support material. Preferably, the support material of the third layer comprises ceria in an amount of at least 65% by weight, more preferably at least 85% by weight, more preferably at least 95% by weight based on the total weight of the support material.
    [0062] Therefore, the present invention relates to the diesel oxidation catalyst as defined above, wherein the support material of the third layer comprises ceria in an amount of at least 65% by weight, preferably at least 85% by weight, more preferably at least 95% by weight based on the total weight of the support material.
    [0063] Preferably, the support material of the third layer additionally comprises zirconia and / or alumina.
    [0064] Therefore, the present invention relates to the diesel oxidation catalyst as defined above, wherein the support material of the third layer additionally comprises zirconia and / or alumina.
    [0065] Preferably, the support material of the third layer comprises a modifier selected from the group consisting of
    18/30
    La 2 O 3 , PrgOn, HfO 2 , Y 2 O 3 , Yb 2 O 3 , YbO, Nd 2 O 3 , NdO, WO 3 , SiO 2 , TiO 2 and combinations of two or more of the same.
    [0066] Therefore, the present invention relates to the diesel oxidation catalyst as defined above, wherein the support material of the third layer additionally comprises a modifier selected from the group consisting of La 2 O 3 , PreOn, HfO 2 , Y 2 O 3 , Yb 2 O 3 , YbO, Nd 2 O 3 , NdO, WO 3 , SiO 2 , TiO 2 and combinations of two or more of the same.
    [0067] More preferably, the support material of the third layer comprises a ceria-zirconia material consisting of CeO 2 : 45% by weight, ZrO 2 : 43.5% by weight, La 2 O 3 : 8% by weight, Pr 6 On: 2% by weight and HfO 2 : 1.5% by weight.
    [0068] Generally, there are no specific restrictions with regard to the palladium content of the third layer, provided that the weight ratio of platinum to palladium of the third layer is less than the weight ratio of platinum to palladium of the second layer. Preferably, the third layer comprises palladium in an amount of 2 to 30 g / ft 3 .
    [0069] Therefore, the present invention relates to the diesel oxidation catalyst as defined above, wherein the third layer comprises palladium in an amount of 2 to 30 g / ft 3 .
    [0070] Generally, there are no specific restrictions regarding the content of platinum in the third layer, provided that the weight ratio of platinum to palladium in the third layer is less than the weight ratio of platinum to palladium in the second layer. Preferably, the third layer comprises platinum in an amount of 4 to 16 g / ft 3 .
    [0071] Therefore, the present invention relates to the diesel oxidation catalyst as defined above, wherein the third layer comprises platinum in an amount of 4 to 16 g / ft 3 .
    [0072] Preferably, the third layer additionally comprises a hydrocarbon storage compound, preferably a zeolite. If present, the third layer comprises
    19/30 the hydrocarbon storage compound in a total amount of 0.1 to 1 g / foot 3 , preferably 0.3 to 0.8 g / foot 3 , more preferably in an amount of 0.5 g / foot 3 foot 3 .
    [0073] Therefore, the present invention relates to the diesel oxidation catalyst as defined above, wherein the third layer additionally comprises a hydrocarbon storage compound, preferably a zeolite.
    [0074] Typically, any types of zeolite / aluminosilicate structure can be used. In this regard, reference is made to the types of structure mentioned for the second layer.
    [0075] The layered diesel oxidation catalyst of the present invention can be used in an integrated system to treat a gaseous exhaust stream from a diesel engine.
    [0076] Therefore, the present invention also relates to the layered diesel oxidation catalyst as defined above comprised in a system for treating a gaseous exhaust stream from a diesel engine, the system further comprising:
    an exhaust conduit in fluid communication with the diesel engine via an exhaust manifold, and one or more of the following in fluid communication with the layered diesel oxidation catalyst composite: a catalytic soot filter (CSF), a selective catalytic reduction (SCR) article, a NOx reduction and storage catalytic article (NSR).
    [0077] Each layer of the catalytic diesel material according to the present invention is formed from a thin-coated composition containing the respective support material as described above. Other additives, such as binders and stabilizers, can also be included in the thin-coated composition. As disclosed in US Patent No. 4,727,052, porous support materials, such as activated alumina, can be thermally stabilized to slow
    20/30 undesirable alumina phase transformations from gamma to alpha at elevated temperatures. Stabilizers can be selected from alkaline earth metal components selected from the group consisting of magnesium, barium, calcium and strontium, preferably strontium and barium. When present, stabilizing materials are added at about 0.01 g / in 3 (g / (2.54 cm) 3 ) to 0.15 g / in 3 (g / (2.54 cm) 3 ) in the coating .
    [0078] The first layer is arranged on the surface of the vehicle substrate or the sub-coating layer. The second layer is arranged on top of the first layer that had been applied on the surface of the vehicle substrate or the subcoat layer. Additionally, it is conceivable that a third layer is arranged on the second layer. It should be understood that a given layer can partially permeate the substrate or the layer on which it is applied.
    [0079] For the preparation of the thin-coated compositions mentioned above, it is preferable to disperse a suitable Pt and / or Pd component precursor over a suitable support material as described above. More preferably, a water soluble or water dispersible Pt and / or Pd component precursor is / are impregnated in a suitable support material, followed by drying and fixing steps. Suitable Pt and / or Pd component precursors include, for example, platinum and potassium chloride, platinum and ammonium thiocyanate, platinum hydroxide solubilized in amine, chloroplatinic acid, palladium nitrate and the like. Other suitable precursors will be apparent to those skilled in the art. The impregnated support material is preferably dried with the Pt and / or Pd component attached to it. Generally, drying temperatures are in the range of 60 to 250 ° C, preferably 90 to 210 ° C, more preferably 100 to 150 ° C. Drying can be carried out in any suitable atmosphere, with N 2 or air being preferred. After drying, it is preferable to finally fix the component
    21/30
    Pt and / or Pd on the support material by suitable calcination and / or other suitable methods, such as treatment with acetic acid. In general, any method resulting in the Pt and / or Pd component being in water insoluble form is suitable. Generally, calcination temperatures are in the range of 250 ° C to 800 ° C, preferably 350 to 700 ° C, more preferably 400 to 600 ° C. Calcination can be performed in any suitable atmosphere, with N 2 or air being preferred. For example, by calcination, catalytically active elemental Pt and / or Pd or the corresponding oxide is obtained. It should be understood that the term platinum or palladium present in the layered diesel oxidation catalyst finally obtained as used in the context of the present invention refers to the Pt and / or Pd component in the form of catalytically active elemental Pt and / or Pd, or their oxide, or the mixture of elemental Pt and / or Pd and their oxide.
    [0080] Therefore, the present invention also relates to a process for preparing the layered diesel oxidation catalyst as defined above, comprising the steps of (i) providing a carrier substrate;
    (ii) optionally applying a subcoat layer to the vehicle substrate;
    (iii) applying a first layer to the carrier substrate or the subcoating layer, the first layer comprising palladium impregnated in a support material comprising ceria in an amount of at least 45% by weight based on the total weight of the support material and optionally comprising platinum;
    (iv) applying a second layer to the first layer, the second layer comprising palladium and platinum, each impregnated in a support material comprising a metal oxide,
    22/30 wherein the weight ratio of platinum to palladium in the first layer is less than the weight ratio of platinum to palladium in the second layer;
    (v) optionally applying a third layer to the second layer, the third layer comprising palladium impregnated in a support material comprising ceria in an amount of at least 45% by weight based on the total weight of the support material and optionally comprising platinum, wherein the weight ratio of platinum to palladium of the third layer is less than the weight ratio of platinum to palladium of the second layer.
    [0081] Additionally, the present invention relates to a system for treating a gaseous exhaust stream from a diesel engine, the system comprising:
    an exhaust conduit in fluid communication with the diesel engine via an exhaust manifold, the layered diesel oxidation catalyst as described above, wherein the vehicle substrate is a wall flow substrate or a through flow substrate , and one or more of the following in fluid communication with the layered diesel oxidation catalyst composite: a catalytic soot filter (CSF), a selective catalytic reduction article (SCR), a NOx reduction and storage catalytic article (NSR).
    [0082] Preferably, in this system, if present, the layered diesel oxidation catalyst is located upstream of the catalyzed soot filter.
    [0083] Therefore, the present invention relates to a system for treating a gaseous exhaust stream from a diesel engine as defined above comprising a catalyzed soot filter, in which the layered diesel oxidation catalyst is located upstream of the catalyzed soot filter.
    23/30 [0084] An SCR article suitable for use in the exhaust conduit is typically capable of catalyzing the reaction of O 2 with any excess NH 3 to N 2 and K 2 O, so that NH 3 is not emitted to the atmosphere. Suitable SCR articles are described, for example, in US4,961,917 and US5,516,497. Suitable SCR articles include one or both of an iron and copper promoter typically present in a zeolite in an amount of about 0.1 to 30 weight percent, preferably about 1 to 5 weight percent, by weight total promoter plus zeolite. Typical zeolites may exhibit a CHA lattice structure.
    [0085] Finally, the present invention relates to a method for treating a gaseous exhaust stream from a diesel engine, said method comprising contacting the gaseous exhaust stream with the layered diesel oxidation catalyst as defined above.
    [0086] In the following, the present invention is further illustrated by the following examples.
    Examples
    1. Preparation of the catalyst
    Sample A) according to the invention [0087] For the first layer (bottom) a palladium nitrate solution was added to 0.75 g / in 3 of highly porous gamma alumina, resulting in 22 g / ft 3 Pd. The resulting frit was dispersed in water and acetic acid and ground to a dg0 particle size of 25 micrometers. In that slurry, 0.75 g / in 3 of a material consisting of ZrO2: 43.5% by weight, CeO 2 : 45% by weight, La 2 O 3 : 8% by weight, Pr 6 On: 2% by weight and HfO 2 : 1.5% was dispersed and ground to a particle size d 90 of 7 micrometers. The final sludge was coated on a monolith, dried at 110 ° C in air and calcined at 450 ° C in air.
    [0088] For the layer 2 (average) 1.5 g / in 3 of highly porous gamma alumina were impregnated with an aqueous palladium nitrate solution, giving a final dry content of 30 g Pd / ft 3. The dust
    The resulting 24/30 was dispersed in water. Platinum with platinum solution as an amine-stabilized Pt IV hydroxide complex was added to give a dry Pt content of 60 g / ft 3 . After adjusting the pH of the slurry to 4.5, the slurry was ground to a particle size d 90 of 16 pm. The final slurry was subsequently coated on the first layer, dried at 110 ° C in air and calcined at 450 ° C in air.
    [0089] For the layer 3 (upper), 0,25 g / in 3 of highly porous gamma-alumina and 0.5 g / in 3 of a material consisting of ZrO 2: 43.5 wt% CeO2: 45% weight, La2O3: 8% by weight, Ργ6Οή: 2% by weight and HfO2: 1.5% were mixed and impregnated with an aqueous palladium nitrate solution, giving a final dry Pd content of 8 g / ft 3 . Subsequently, the impregnated material was dispersed in water and acetic acid and ground to a d90 particle size of 20 micrometers. 0.5 g / in 3 of H-beta zeolite was immersed in water to a solids content of 45%. The slurry containing precious metal was mixed with the slurry containing zeolite H-beta, ground to a particle size d90 of 15 pm and subsequently coated in the second layer, dried at 110 ° C in air and calcined at 450 ° C in air .
    Sample B) according to the invention [0090] For the first layer (bottom) a palladium nitrate solution was added to a mixture of highly porous gamma alumina (0.75 g / in 3) and 100% of ceria materials (0.75 g / in 3 ), resulting in 36 g / foot 3 of Pd. The resulting frit was dispersed in water and acetic acid and ground to a particle size d 90 of 7 micrometers. The final sludge was coated on a monolith, dried at 110 ° C in air and calcined at 450 ° C in air.
    [0091] For the layer 2 (average) 1.5 g / in 3 of highly porous gamma alumina were impregnated with an aqueous palladium nitrate solution, giving a final dry content of 26 g Pd / ft 3. The resulting powder was dispersed in water. Platinum to platinum solution as an amine-stabilized Pt IV hydroxide complex was added to give a
    25/30 dry Pt content of 52 g / ft 3 . After adjusting the pH of the slurry to 4.5, the slurry was ground to a particle size d 90 of 16 pm. The final slurry was subsequently coated on the first layer, dried at 110 ° C in air and calcined at 450 ° C in air.
    [0092] For the layer 3 (upper), highly porous gamma-alumina (0.25 g / in 3) and 100% ceria material (0.5 g / in 3) were mixed and impregnated with an aqueous solution of palladium nitrate, giving a final dry Pd content of 8 g / ft 3 . Subsequently, the impregnated material was dispersed in water and acetic acid and ground to a d90 particle size of 20 micrometers. 0.5 g / in 3 of H-beta zeolite was immersed in water to a solids content of 45%. The slurry containing precious metal was mixed with the slurry containing zeolite H-beta, milled to a d90 particle size of 15 pm and subsequently coated in the second layer, dried at 110 ° C in air and calcined at 450 ° C in air.
    Sample C) according to the invention [0093] For the first layer (bottom) a palladium nitrate solution was added to a mixture of highly porous gamma alumina (0.75 g / in 3) and 100% material of Ceria (0.75 g / in 3 ), resulting in 30 g / foot 3 of Pd. The resulting frit was dispersed in water and acetic acid and ground to a particle size d 90 of 7 micrometers. The final sludge was coated on a monolith, dried at 110 ° C in air and calcined at 450 ° C in air.
    [0094] For the layer 2 (average), 1 g / in 3 of highly porous gamma-alumina was impregnated with an aqueous palladium nitrate solution, giving a final dry content of 30 g Pd / ft 3. The resulting powder was dispersed in water. Platinum with platinum solution as an amine-stabilized Pt IV hydroxide complex was added to give a dry Pt content of 60 g / ft 3 . After adjusting the pH of the slurry to 4.5, the slurry was ground to a particle size d 90 of 16 pm. Zeolite H-beta was immersed in water at a solids content of 45%. The sludge containing precious metal was then mixed with the sludge containing H-beta zeolite, ground to
    26/30 a particle size d90 of 15 pm and subsequently coated in one layer, dried at 110 ° C in air and calcined at 450 ° C in air.
    Sample D) not according to the invention [0095] For the first layer (bottom) a palladium nitrate solution was added to 0.75 g / in 3 of highly porous gamma alumina, resulting in 22 g / ft 3 of Pd. The resulting frit was dispersed in water and acetic acid and ground to a particle size d90 of 25 micrometers. In this slurry, 0.75 g / in 3 of highly porous gamma-alumina was dispersed and ground to a d90 particle size of 7 micrometers. The final sludge was coated on a monolith, dried at 110 ° C in air and calcined at 450 ° C in air.
    [0096] For the layer 2 (average) 1.5 g / in 3 of highly porous gamma alumina were impregnated with an aqueous palladium nitrate solution, giving a final dry content of 30 g Pd / ft 3. The resulting powder was dispersed in water. Platinum with platinum solution as an amine-stabilized Pt IV hydroxide complex was added to give a dry Pt content of 60 g / ft 3 . After adjusting the pH of the slurry to 4.5, the slurry was ground to a particle size d 90 of 16 pm. The final slurry was subsequently coated on the first layer, dried at 110 ° C in air and calcined at 450 ° C in air.
    [0097] For the layer 3 (average) 0.75 g / in 3 of highly porous gamma alumina were impregnated with an aqueous palladium nitrate solution, giving a final dry content of 8 g Pd / ft 3. Subsequently, the impregnated material was dispersed in water and acetic acid and ground to a d90 particle size of 20 micrometers. 0.5 g / in 3 of H-beta zeolite was immersed in water to a solids content of 45%. The slurry containing precious metal was mixed with the slurry containing H-beta zeolite, ground to a particle size d90de 15 pm and subsequently coated in the layer 2, dried at 110 ° C in air and calcined at 450 ° C in air.
    Sample E) not according to the invention
    27/30 [0098] For the layer 1 (below) 1 g / in 3 of highly porous gamma-alumina was dispersed in water and acetic acid , and milled to a particle size d90 of 15 micrometers. The final slurry was coated on a monolith, dried at 110 ° C in air and calcined at 450 ° C in air.
    [0099] For the layer 2 (average) 1.5 g / in 3 of highly porous gamma alumina were impregnated with an aqueous palladium nitrate solution, giving a final dry content of 28 g Pd / ft 3. The resulting powder was dispersed in water. Platinum with platinum solution as an amine-stabilized Pt IV hydroxide complex was added to give a dry Pt content of 52 g / ft 3 . After adjusting the pH of the slurry to 4.5, the slurry was ground to a particle size d 90 of 16 pm. The final slurry was subsequently coated on the first layer, dried at 110 ° C in air and calcined at 450 ° C in air.
    [0100] For the layer 3 (top), 0.25 g / in 3 of highly porous gamma alumina were dispersed in water and acetic acid and milled to a d90 particle size of 20 micrometers. 0.5 g / in 3 of H-beta zeolite was immersed in water to a solids content of 45%. To this sludge, a platinum precursor solution with platinum as an amine-stabilized Pt IV hydroxide complex was added to give a dry Pt content of 8g / ft 3 . The slurry containing precious metal was mixed with the slurry containing alumina, ground to a particle size d90 of 15 pm and subsequently coated in the layer 2, dried at 110 ° C in air and calcined at 450 ° C in air.
    2, HC / QC Gas Activity Performance Test
    Sample A) according to the invention [0101] first layer: 22 g / ft 3 Pd, 0.75 g / in 3 (ZrO 2: 43.5 wt% CeO 2: 45 wt% La 2 O 3 : 8% by weight, Pr 6 On: 2% by weight and HfO 2 : 1.5%), 0.75 g / in 3 of highly porous gamma-alumina [0102] 2 a Layer: 60 g / foot 3 Pt, 30 g / ft 3 Pd, 1.5 g / in 3 highly porous gamma-alumina
    28/30 [0103] 3rd a Layer: 8 g / ft 3 of Pd, 0.25 g / in 3 of highly porous gamma-alumina, zeolite H-Beta 0.5 g / in 3 , 0.5 g / in 3 (ZrO 2 : 43.5% by weight, CeO 2 : 45% by weight, La 2 O 3 : 8% by weight, ΡτθΟ ^: 2% by weight and HfO 2 : 1.5%)
    Sample B) according to the invention [0104] first layer: 36 g / ft 3 of Pd, 0.75 g / in 3 ceria, 0.75 g / in 3 of highly porous gamma alumina [0105] 2 a Layer: 52 g / foot 3 of Pt, 26 g / foot 3 of Pd, 1.5 g / inch 3 of highly porous gamma-alumina [0106] 3 a Layer: 16 g / foot 3 of Pd, 0.25 g / inch 3 of highly porous gamma-alumina, H-Beta zeolite 0.5 g / inch 3 , 0.5 g / inch 3 of 100% Ceria
    Sample C) according to the invention [0107] first layer: 36 g / ft 3 of Pd, 0.75 g / in 3 ceria, 0.75 g / in 3 of highly porous gamma alumina [0108] 2 a Layer: 60 g / ft 3 of Pt, 30 g / inch 3 of Pd, 1 g / inch 3 of highly porous gamma alumina, 0.5 g / inch 3 of H-Beta zeolite
    Sample D) not according to the invention [0109] 1 a layer: 22 g / ft 3 of Pd, 1.5 g / in 3 of highly porous gamma-alumina [0110] 2 a Layer: 60 g / ft 3 of Pt, 30 g / foot 3 of Pd, 1.5 g / inch 3 of highly porous gamma-alumina [0111] 3 a Layer: 8 g / foot 3 of Pd, 0.75 g / inch 3 of highly porous alumina porous, 0.5 g / in 3 of H-Beta zeolite
    Sample E) not according to the invention [0112] first layer: 1 g / in 3 of highly porous gamma alumina [0113] 2 Layer: 72 g / ft 3 of Pt, 40 g / ft 3 of Pd, 1.5 g / inch 3 of highly porous gamma-alumina [0114] 3 a Layer: 8 g / ft 3 of Pt, 0.25 g / inch 3 of highly porous gamma-alumina, 0.5 g / inch 3 of zeolite H-Beta
    3. Liqht-off Performance Test
    29/30 [0115] Samples A), B), C), D) and E) were tested for CO and HC light-off performance. Before the tests, the samples were aged in the exhaust chain of a light 4-cylinder diesel engine with an engine displacement of 2.7 L for 25 h. The exhaust current temperature was raised by a 750 ° C steady-state burner upstream, [0116] For light-off tests, each sample was placed downstream in the exhaust line of a 6-cylinder light diesel engine with engine displacement of 3 L. The concentration of CO and HC in the exhaust current was constant at 1500 ppm and 300 ppm (base C 3 ), respectively. The gas flow under standard conditions was around 60 m 3 / h. The temperature threshold was 40 ° C / min.
    [0117] A lower light-off temperature characterizes better gas activity.
    [0118] As can be understood from Figure 1 showing the CO light-off curves for Samples A), B), C), D) and E), Samples A), B) and C) according to the invention shows greater CO conversion at lower temperatures compared to Samples D) and E) not according to the invention.
    [0119] As can be understood from Figure 2 showing the HC light-off curves for Samples A), B), C), D) and E), Samples A) and B) according to the invention show greater conversion of HC at lower temperatures compared to Samples D) and E) not according to the invention. Sample C) according to the invention shows a lower light-off temperature of around 70% of HC conversion compared to Samples D) and E) not according to the invention.
    [0120] As can be understood from Figure 3 showing the HC and CO light-off curves for Samples A), B), C), D) and E), Samples A), B) and C) with reduced precious metal cost according to the invention show lower light-off temperatures at 50%
    30/30
    conversion of CO and 70% conversion of HC compared to Samples D) and E) not according to the invention.
    权利要求:
    Claims (31)
    [1]
    1. Layered diesel oxidation catalyst (DOC), characterized by the fact that it comprises:
    a) a carrier substrate;
    b) a diesel oxidation catalytic material comprising b1) a first layer located on the carrier substrate, the first layer comprising palladium impregnated on a support material comprising ceria in an amount of at least 45% by weight based on the total weight of the support material and optionally comprising platinum;
    b2) a second layer located on the first layer, the second layer comprising palladium and platinum, each impregnated in a support material comprising a metal oxide;
    wherein the weight ratio of platinum to palladium in the first layer is less than the weight ratio of platinum to palladium in the second layer.
    [2]
    2. Diesel oxidation catalyst, according to claim 1, characterized by the fact that the weight ratio of platinum to palladium of the first layer is in the range of 0: 1 to 1.1: 1.
    [3]
    3. Diesel oxidation catalyst, according to claim 1 or 2, characterized by the fact that the weight ratio of platinum to palladium of the second layer is in the range of 1: 0 to 1.1: 1, preferably in the range from 10: 1 to 1.5: 1, more preferably in the range of 5: 1 to 2: 1, more preferably in the range of 2: 1.
    [4]
    4. Diesel oxidation catalyst according to any one of claims 1 to 3, characterized in that the ratio of the weight ratio of platinum to palladium of the first layer to the weight ratio of platinum to palladium of the second layer is less than or equal to 0.9.
    2/7
    [5]
    Diesel oxidation catalyst according to any one of claims 1 to 4, characterized in that the support material of the first layer comprises ceria in an amount of at least 65% by weight, preferably at least 85% by weight. weight more
    5 preferably at least 95% by weight based on the total weight of the support material.
    [6]
    6. Layered diesel oxidation catalyst according to any one of claims 1 to 5, characterized in that the support material of the first layer additionally comprises zirconia
    10 and / or alumina.
    [7]
    Diesel oxidation catalyst according to any one of claims 1 to 6, characterized in that the support material of the first layer additionally comprises a modifier selected from the group consisting of La 2 O 3 , PrgOn, HfO 2 , Y 2 O 3 ,
    15 Yb 2 O 3 , YbO, Nd 2 O 3 , NdO, WO 3 , SiO 2 , TiO 2 and combinations of two or more of the same.
    [8]
    Diesel oxidation catalyst according to any one of claims 1 to 7, characterized in that the support material of the second layer comprises a metal oxide selected from
    20 from the group consisting of alumina, zirconia, silica, titania, silicaalumina, alumina-zirconia, titania-silica, titania-zirconia, titania-alumina and combinations of two or more of the same.
    [9]
    9. Layered diesel oxidation catalyst according to any one of claims 1 to 8, characterized by the fact that the
    The second layer has a ceria content of not more than 5% by weight, preferably not more than 1% by weight, more preferably not more than 0.1% by weight.
    [10]
    10. Layered diesel oxidation catalyst according to any one of claims 1 to 9, characterized by the fact that the
    The first layer comprises palladium in an amount of 6 to 60 g / ft 3 .
    3/7
    [11]
    11. Layered diesel oxidation catalyst composite according to any one of claims 1 to 10, characterized in that the first layer comprises platinum in an amount of 15 to 40 g / ft 3 .
    [12]
    12. Layered diesel oxidation catalyst according to any one of claims 1 to 11, characterized in that the second layer comprises platinum and palladium in a total amount of 30 to 180 g / ft 3 .
    [13]
    13. Layered diesel oxidation catalyst according to any one of claims 1 to 12, characterized in that the diesel oxidation catalytic material comprises platinum and palladium in a total amount of 30 to 240 g / ft 3 based on.
    [14]
    Layered diesel oxidation catalyst according to any one of claims 1 to 13, characterized in that the second layer additionally comprises a hydrocarbon storage compound, preferably a zeolite.
    [15]
    Layered diesel oxidation catalyst according to any one of claims 1 to 14, characterized in that it additionally comprises an undercoat layer located between the vehicle substrate and the first layer.
    [16]
    16. Layered diesel oxidation catalyst according to claim 15, characterized by the fact that the undercoat layer comprises alumina.
    [17]
    17. Layered diesel oxidation catalyst according to any one of claims 1 to 16, characterized in that the carrier substrate is a through-flow substrate or a wall-flow substrate.
    [18]
    18. Diesel oxidation catalyst according to any one of claims 1 to 17, characterized by the fact that the vehicle substrate comprises a material selected from the group
    4/7 consisting of cordierite, cordierite-alumina, silicon nitride, silicon carbide, zirconium mullite, spodumene, silica-alumina magnesia, zirconium silicate, silimanite, magnesium silicate, zirconium, petalite, alumina, alumosilicate and combinations two or more of them.
    [19]
    19. Layered diesel oxidation catalyst according to any one of claims 1 to 18, characterized in that it additionally comprises b3) a third layer located on the second layer, the third layer comprising palladium impregnated on a support material comprising ceria in an amount of at least 45% by weight based on the total weight of the support material and optionally comprising platinum;
    wherein the weight ratio of platinum to palladium of the third layer is less than the weight ratio of platinum to palladium of the second layer.
    [20]
    20. Diesel oxidation catalyst according to claim 19, characterized in that the ratio of the weight ratio of platinum to palladium of the third layer to the weight ratio of platinum to palladium of the second layer is less than or equal to 0.9.
    [21]
    21. Diesel oxidation catalyst according to claim 19 or 20, characterized in that the support material of the third layer comprises ceria in an amount of at least 65% by weight, preferably at least 85% by weight, more preferably at least 95% by weight based on the total weight of the support material.
    [22]
    22. Layered diesel oxidation catalyst according to any one of claims 19 to 21, characterized in that the support material of the third layer additionally comprises zirconia and / or alumina.
    5/7
    [23]
    23. Diesel oxidation catalyst according to any one of claims 19 to 22, characterized in that the support material of the third layer further comprises a modifier selected from the group consisting of 1_a 2 O 3 , Pr 6 O 11 ( HfO 2 , Y 2 O 3 , Yb 2 O 3 , YbO, Nd 2 O 3 , NdO, WO 3 , SiO 2 , TiO 2 and combinations of two or more of the same.
    [24]
    24. Layered diesel oxidation catalyst according to any of claims 19 to 23, characterized in that the third layer comprises palladium in an amount of 2 to 30 g / ft 3 .
    [25]
    25. Diesel layer oxidation catalyst according to any one of claims 19 to 24, characterized in that the third layer comprises platinum in an amount of 4 to 16 g / ft 3 .
    [26]
    26. Layered diesel oxidation catalyst according to any one of claims 19 to 25, characterized in that the third layer additionally comprises a hydrocarbon storage compound, preferably a zeolite.
    [27]
    27. Layered diesel oxidation catalyst according to any one of claims 1 to 26, characterized in that it is comprised in a system for treating a gaseous exhaust stream from a diesel engine, the system further comprising:
    an exhaust conduit in fluid communication with the diesel engine via an exhaust manifold, and one or more of the following in fluid communication with the layered diesel oxidation catalyst composite: a catalytic soot filter (CSF), a selective catalytic reduction (SCR) article, a NOx reduction and storage catalytic article (NSR).
    [28]
    28. Process, characterized by the fact that it is for the preparation of the layered diesel oxidation catalyst according to any one of claims 1 to 26, comprising the steps of
    6/7 (i) providing a carrier substrate;
    (ii) optionally applying a subcoat layer to the vehicle substrate;
    (iii) applying a first layer to the carrier substrate or the subcoating layer, the first layer comprising palladium impregnated in a support material comprising ceria in an amount of at least 45% by weight based on the total weight of the support material and optionally comprising platinum;
    (iv) applying a second layer to the first layer, the second layer comprising palladium and platinum, each impregnated in a support material comprising a metal oxide, in which the weight ratio of platinum to palladium in the first layer is less than the platinum to palladium weight ratio of the second layer;
    (v) optionally applying a third layer to the second layer, the third layer comprising palladium impregnated in a support material comprising ceria in an amount of at least 45% by weight based on the total weight of the support material and optionally comprising platinum, wherein the weight ratio of platinum to palladium of the third layer is less than the weight ratio of platinum to palladium of the second layer.
    [29]
    29. System for treating a gaseous exhaust stream from a diesel engine, characterized by the fact that the system comprises:
    an exhaust conduit in fluid communication with the diesel engine by means of an exhaust manifold, the layered diesel oxidation catalyst, according to any one of claims 1 to 26, wherein the vehicle substrate is a flow substrate in wall or a through-flow substrate, and
    7/7 one or more of the following in fluid communication with the layered diesel oxidation catalyst composite: a catalytic soot filter (CSF), a selective catalytic reduction article (SCR), a catalytic reduction and storage article NOx (NSR).
    5
    [30]
    30. System according to claim 29, characterized by the fact that it comprises a catalyzed soot filter, in which the layered diesel oxidation catalyst is located upstream of the catalyzed soot filter.
    [31]
    31. Use, characterized by the fact that it is the catalyst of
    Oxidation of layered diesel according to any one of claims 1 to 26 to treat a gaseous exhaust stream from a diesel engine.
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    同族专利:
    公开号 | 公开日
    MX2014003469A|2014-08-26|
    WO2013042080A1|2013-03-28|
    CN103945936A|2014-07-23|
    BR112014006900B8|2019-10-15|
    JP2014527909A|2014-10-23|
    IN2014CN02204A|2015-06-12|
    MX368239B|2019-09-25|
    JP6236389B2|2017-11-22|
    BR112014006900A2|2017-04-11|
    CA2849700C|2020-02-18|
    EP2758168A4|2015-12-02|
    PL2758168T3|2020-02-28|
    EP2758168A1|2014-07-30|
    KR102064620B1|2020-01-09|
    EP2758168B1|2019-07-31|
    CA2849700A1|2013-03-28|
    CN103945936B|2016-11-16|
    KR20140073533A|2014-06-16|
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    法律状态:
    2018-12-11| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]|
    2019-06-18| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|
    2019-08-20| B16A| Patent or certificate of addition of invention granted [chapter 16.1 patent gazette]|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 21/09/2012, OBSERVADAS AS CONDICOES LEGAIS. (CO) 20 (VINTE) ANOS CONTADOS A PARTIR DE 21/09/2012, OBSERVADAS AS CONDICOES LEGAIS |
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    优先权:
    申请号 | 申请日 | 专利标题
    EP11182585.7|2011-09-23|
    EP11182585|2011-09-23|
    PCT/IB2012/055030|WO2013042080A1|2011-09-23|2012-09-21|Diesel oxidation catalyst with layered structure containing ceria composition as palladium support material for enhanced hc and co gas conversion|
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