CN208302793U - Novel multi TWC catalyst for gasoline exhaust processing - Google Patents

Abstract

Disclose a kind of three-way catalyst product, and its purposes in the exhaust system for internal combustion engine.Catalyst article for handling exhaust gas includes: including arrival end, outlet end and the carrier with axial length L；Start from the arrival end and extend less than the first catalysis region of the axial length L, wherein first catalysis region includes the first palladium component；Start from the outlet end and extend less than the second catalysis region of the axial length L, wherein second catalysis region includes the second palladium component；Start from the outlet end and extend less than the third catalysis region of the axial length L, wherein the third catalysis region includes third rhodium component；Wherein the third catalysis region is stacked on second catalysis region.

Description

Novel multi TWC catalyst for gasoline exhaust processing

Technical field

The utility model relates to the catalytic articles of the exhaust gas discharge for handling gasoline engine.

Background technique

Internal combustion engine generates the exhaust gas containing multiple pollutant, and pollutant includes hydrocarbon (HC), carbon monoxide (CO) and nitrogen oxidation Object (" NO_x").The emission control systems comprising exhaust fume catalytic reforming catalyst are widely used to reduce these pollutant emissions To the amount of atmosphere.Custom catalysts for gasoline engine vent gas treatment are TWC (three-way catalysts).TWC executes three main function Can: (1) oxidation of CO；(2) oxidation of unburned HC；(3) NO_xReduction.

In most catalytic converters, TWC is applied to the high surface area carrier such as flow type honeycomb that can bear high temperature On body carrier.The high surface area of these carriers is conducive to improve the efficiency of heterogeneous reaction, but will increase exhaust back pressure, that is, limits Exhaust gas flows to offgas duct from engine.Although TWC technology achieves progress, such as United States Patent (USP) 6,022,825, United States Patent (USP) 9, 352,279, United States Patent (USP) 9,040,003 and U.S. Patent Publication 2016/0228818 described in those, but there is still a need for In the improved catalytic converter of certain engine flats, the performance of cold-start phase is improved simultaneously and/or is provided better Ignition performance.The utility model especially solves these problems.

Utility model content

The one aspect of the utility model is related to the catalyst for handling gasoline exhaust, it includes: including arrival end, Outlet end and the carrier with axial length L；Start from the arrival end and extends less than the first catalytic domain of the axial length L Domain, wherein first catalysis region includes the first palladium component；Start from the outlet end and extends less than the second of the axial length L Catalysis region, wherein second catalysis region includes the second palladium component；Start from the outlet end and extends less than the axial length L Third catalysis region, wherein the third catalysis region include third rhodium component；Wherein the third catalysis region be stacked in this On two catalysis regions.

The utility model further includes the exhaust system for internal combustion engine, and it includes the three-way catalyst portions of the utility model Part.

Detailed description of the invention

Fig. 1 shows an embodiment according to the present utility model, the second catalysis region and the first catalysis region it is total Length is equal to the axial length L of carrier.

Fig. 2 a and Fig. 2 b show two embodiments according to the present utility model, the second catalysis region and the first catalytic domain Domain overlapping.

Fig. 3 shows an embodiment according to the present utility model, the second catalysis region and the first catalysis region it is total Length is less than the axial length L of carrier.

Fig. 4 a, 4b and 4c show the vehicle testing respectively from catalyst A, comparative catalyst B and comparative catalyst C THC, CO and NO that accumulative dilution bag is adopted_xDischarge.

Specific embodiment

The utility model relates to the catalytic treatments for the exhaust gas that burning waste gas is such as generated by gasoline engine and other engines, and relate to And relevant catalyst and system.More specifically, the utility model relates to the NO in vehicle exhaust system_x, CO and HC while Processing.The inventors discovered that the conspiracy relation between certain metals and their coating method with catalytic activity, goes out people Expect ground and generates NO_x, CO and HC high conversion；Improve the performance in cold-start phase；And provide better ignition performance.

The one aspect of the utility model is related to the catalyst article for handling exhaust gas, it includes: including arrival end, go out Mouth end and the carrier with axial length L；Start from the arrival end and extend less than the first catalysis region of the axial length L, Wherein first catalysis region includes the first palladium component；Start from the outlet end and extend less than the second of the axial length L urging Change region, wherein second catalysis region includes the second palladium component；Start from the outlet end and extends less than the axial length L Third catalysis region, wherein the third catalysis region includes third rhodium component；Wherein the third catalysis region be stacked in this second On catalysis region.

The inventors discovered that showing superior catalyst performance using the catalyst of this coating method, this is to make It is irrealizable with the catalyst institute of individual or conventional coating method.The unexpected benefit of the utility model is, with class It is compared like the conventional TWC catalyst of concentration (such as carrier coating (washcoat) load capacity), there is excellent catalyst light-off Performance can significantly reduce the discharge of exhaust contaminant in vehicle cold-start phase, to more easily reach emissions object.These The acquisition of benefit, can reduce the dosage of noble metal in catalyst, to reduce cost.

First catalysis region can extend the 30-70% of axial length L.Preferably, the first catalysis region can be with outrigger shaft To the 40-60% of length L, more preferable 45-55%.

Second catalysis region can extend the 30-70% of axial length L.Preferably, the second catalysis region can be with outrigger shaft To the 40-60% of length L, more preferable 45-55%.

Second catalysis region can axial length L Chong Die with the first catalysis region 0.1-15% (for example, see Fig. 2 a and Fig. 2 b, the first catalysis region can be stacked on the second catalysis region or the second catalysis region can be stacked in the first catalytic domain On domain).Optionally, the total length of the second catalysis region and the first catalysis region can be equal to axial length L (for example, see figure 1).In another option, the total length of the second catalysis region and the first catalysis region can be less than axial length L, such as less In 95%, 90%, 80% or 70% (for example, see Fig. 3) of axial length L.

Third catalysis region can extend the 50-99% of axial length L.Preferably, third catalysis region can be with outrigger shaft To the 50-95% of length L, more preferable 60-95%.

First catalysis region can be substantially free of the PGM metal except the first palladium component.

First catalysis region may include 0.1-300g/ft³The first palladium component.Preferably, the first catalysis region can be with Include 50-250g/ft³The first palladium component, more preferable 100-220g/ft³The first palladium component.

Total carrier coating load capacity of first catalysis region can be less than 3.5g/in³, preferably smaller than 3.0g/in³, 2.5g/ in³Or 1.5g/in³。

First catalysis region can further include first storage oxygen (OSC) material, the first alkali or alkaline earth metal component And/or first inorganic oxide.

First OSC material is preferably selected from cerium oxide, zirconium oxide, Ceria-zirconia mixed oxide and alumina-silica Cerium-zirconia mixed oxide.It is highly preferred that the first OSC material includes Ceria-zirconia mixed oxide.Cerium oxide-oxygen Some doped chemicals, such as lanthanum, neodymium, praseodymium, yttrium oxide can be further included by changing Zr mixed oxide.In addition, the first OSC material Material may act as the carrier material of the first palladium component.

First palladium component can be supported on the first inorganic oxide and the first OSC material.

Ceria-zirconia mixed oxide at least 50:50, preferably greater than 60:40, more preferably greater than mole of 75:25 Than.

First OSC material (such as Ceria-zirconia mixed oxide) can be total load based on the first catalysis region The 10-90wt% of body coating load amount, preferably 25-75wt%, more preferable 30-60wt%.

The first OSC material load capacity in first catalysis region can be less than 1.5g/in³.In some embodiments, The first OSC material load capacity in one catalysis region is not more than 1.2g/in³, 1.0g/in³, 0.9g/in³, 0.8g/in³Or 0.7g/in³。

In some embodiments, the first alkali or alkaline earth metal can be deposited in the first OSC material.Alternatively or Additionally, the first alkali or alkaline earth metal can be deposited on the first inorganic oxide.I.e. in some embodiments, first Alkali or alkaline earth metal can be deposited on, that is, be present in the first OSC material and first inorganic oxide the two.

First alkali or alkaline earth metal is generally contacted with the first inorganic oxide.Preferably, the first alkali metal or alkali Earth metal is supported on the first inorganic oxide.Or first alkali or alkaline earth metal can also be contacted with the first OSC material.

First alkali or alkaline earth metal is preferably barium or strontium and its mixed oxide or composite oxides.Preferably, when In the presence of, the load capacity of barium or strontium is the total weight 0.1-15wt% based on the first catalysis region, more preferable 3-10wt%'s Barium or strontium.

Even further preferably, the first alkali or alkaline earth metal is strontium.When it is present, the load capacity of strontium is preferably based on The total weight 0.1-15wt%, more preferable 3-10wt% of one catalysis region.

It is also preferred that the first alkali or alkaline earth metal is the mixed oxide or composite oxides of barium and strontium.It is preferred that The mixed oxide of ground, barium and strontium or the amount of composite oxides are the total weight 0.1- based on the first catalysis region 15wt%, more preferable 3-10wt%.It is further preferred that the first alkali or alkaline earth metal is the composite oxides of barium and strontium.

Preferably, barium or strontium are as BaCO₃Or SrCO₃Form exists.Such material can be with known in the art any Method, such as incipient wetness impregnation or spray drying are to obtain.

First inorganic oxide is preferably the oxide of the race of the 2nd, 3,4,5,13 and 14 element.First inorganic oxide is preferred Selected from aluminium oxide, magnesia, silica, cerium oxide, ba oxide and its mixed oxide or composite oxides.Particularly preferably Ground, the first inorganic oxide are aluminium oxide, lanthanum-aluminium oxide, cerium oxide or magnesia/alumina composite oxide.One kind is especially Preferred first inorganic oxide is aluminium oxide or lanthanum-alumina composite oxide.

First OSC material and the first inorganic oxide can have no more than 10:1, preferably no greater than 8:1 or 5:1, more excellent Choosing is not more than 4:1 or 3:1, the most preferably no greater than weight ratio of 2:1.

Alternatively, the first OSC material and the first inorganic oxide can have 10:1-1:10, preferably 8:1-1:8 or 5:1- 1:5, more preferable 4:1-1:4 or 3:1-1:3, the most preferably weight ratio of 2:1-1:2.

Second catalysis region can be substantially free of the PGM metal except the second palladium component.

Second catalysis region may include 0.1-100g/ft³The second palladium component.Preferably, the second catalysis region can be with Include 5-60g/ft³, more preferable 10-50g/ft³The second palladium component.

Second catalysis region can further include second storage oxygen (OSC) material, the second alkali or alkaline earth metal component And/or second inorganic oxide.

Second OSC material is preferably selected from cerium oxide, zirconium oxide, Ceria-zirconia mixed oxide and alumina-silica Cerium-zirconia mixed oxide.It is highly preferred that the second OSC material includes Ceria-zirconia mixed oxide.In addition, second OSC material can further include one or more of doped chemical such as lanthanum, neodymium, praseodymium, yttrium etc..Also, the second OSC material can To serve as the carrier material of the second palladium component.

Second palladium component can be supported on the second inorganic oxide and the second OSC material.

Ceria-zirconia mixed oxide can have zirconium oxide and cerium oxide at least 50:50, preferably greater than 60:40, The more preferably greater than molar ratio of 75:25.

Second OSC material (such as Ceria-zirconia mixed oxide) can be total load based on the second catalysis region Body coating load meter 10-90wt%, preferably 25-75wt%, more preferable 30-60wt%.

The second OSC material load capacity in second catalysis region can be less than 1.5g/in³.In some embodiments, The second OSC material load capacity in two catalysis regions is not more than 1.2g/in³, 1.0g/in³, 0.9g/in³, 0.8g/in³Or 0.7g/in³。

Total carrier coating load capacity of second catalysis region can be less than 3.5g/in³, preferably smaller than 3.0g/in³, 2.5g/ in³Or 1.5g/in³。

In some embodiments, the second alkali or alkaline earth metal can be deposited in the second OSC material.Alternatively or Additionally, the second alkali or alkaline earth metal can be deposited on the second inorganic oxide.I.e. in some embodiments, second Alkali or alkaline earth metal can be deposited on, that is, be present in the second OSC material and second inorganic oxide the two.

Second alkali or alkaline earth metal is generally contacted with the second inorganic oxide.Preferably, the second alkali metal or alkali Earth metal is supported on the second inorganic oxide.For being contacted with the second inorganic oxide additionally or alternatively, second Alkali or alkaline earth metal can be contacted with the second OSC material.

Second alkali or alkaline earth metal is preferably barium, strontium, its mixed oxide or composite oxides.Preferably, when depositing When, the content of barium or strontium is the total weight 0.1-15wt% based on the second catalysis region, the barium of more preferable 3-10wt% or Strontium.

Even further preferably, the second alkali or alkaline earth metal is strontium.When it is present, the amount of strontium is preferably based on The total weight 0.1-15wt%, more preferable 3-10wt% of two catalysis regions.

It is also preferred that the second alkali or alkaline earth metal is the mixed oxide or composite oxides of barium and strontium.It is preferred that The mixed oxide of ground, barium and strontium or the amount of composite oxides are the total weight 0.1- based on the second catalysis region 15wt%, more preferable 3-10wt%.It is further preferred that the second alkali or alkaline earth metal is the composite oxides of barium and strontium.

Preferably, barium or strontium are as BaCO₃Or SrCO₃Form exists.Such material can be with any side known in the art Method, such as incipient wetness impregnation or spray drying are to obtain.

Second inorganic oxide is preferably the oxide of the race of the 2nd, 3,4,5,13 and 14 element.Second inorganic oxide is preferred Selected from aluminium oxide, magnesia, silica, cerium oxide, ba oxide and its mixed oxide or composite oxides.Particularly preferably Ground, the second inorganic oxide are aluminium oxide, lanthanum-aluminium oxide, cerium oxide or magnesia/alumina composite oxide.One kind is especially Preferred second inorganic oxide is aluminium oxide or lanthanum-alumina composite oxide.

Second OSC material and the second inorganic oxide can have no more than no more than 10:1, preferably no greater than 8:1 or 5: 1, more preferably no more than 4:1 or 3:1, the most preferably no greater than weight ratio of 2:1.

Alternatively, the second OSC material and the second inorganic oxide can have 10:1-1:10, preferably 8:1-1:8 or 5:1- 1:5, more preferable 4:1-1:4 or 3:1-1:3, the most preferably weight ratio of 2:1-1:2.

Third catalysis region can be substantially free of the PGM metal except third rhodium component.

Third catalysis region may include 0.1-20g/ft³Third rhodium component.Preferably, third catalysis region may include 3-15g/ft³, more preferable 5-13g/ft³Third rhodium component.

Total carrier coating load capacity of third catalysis region can be less than 3.5g/in³；It is preferably less than 3.0g/in³Or 2g/in³；It is more preferably, less than 1.5g/in³Or 1.0g/in³。

Third catalysis region can further include third storage oxygen (OSC) material, third alkali or alkaline earth metal component and/ Or third inorganic oxide.

Third OSC material is preferably selected from cerium oxide, zirconium oxide, Ceria-zirconia mixed oxide and alumina-silica Cerium-zirconia mixed oxide.Preferably, third OSC material include Ceria-zirconia mixed oxide, and have lanthanum, The one or more of the doped chemicals such as neodymium, yttrium, praseodymium.In addition, third OSC material may act as the carrier material of third rhodium component.

Ceria-zirconia mixed oxide can have zirconium oxide and cerium oxide to be at least 50:50, preferably greater than 60:40, The more preferably greater than molar ratio of 80:20.

Third OSC material can load meter 10-90wt% for total carrier coating based on third catalysis region, preferably 25-75wt%, more preferable 35-65wt%.

Third OSC material load capacity in third catalysis region is smaller than 2g/in³.In some embodiments, third is urged The third OSC material load capacity changed in region is not more than 1.5g/in³, 1.2g/in³, 1.0g/in³Or 0.5g/in³。

Preferably, third catalysis region is generally free of third alkali or alkaline earth metal, more preferably substantially free of Three alkali or alkaline earth metals.

Third inorganic oxide is preferably the oxide of the race of the 2nd, 3,4,5,13 and 14 element.Third inorganic oxide is preferred Selected from aluminium oxide, cerium oxide, magnesia, silica, lanthanum, zirconium, neodymium, praseodymium oxide and its mixed oxide or combined oxidation Object.It is particularly preferred that third inorganic oxide is aluminium oxide, lanthanum/alumina composite oxide or zirconium/alumina composite oxidation Object.A kind of especially preferred third inorganic oxide is lanthanum/alumina composite oxide or zirconium/alumina composite oxide.The Three inorganic oxides can be the carrier material of third rhodium component and/or third OSC material.

Preferred third inorganic oxide preferably has greater than 80m²The fresh surface area of/g, the pore volume of 0.1-4mL/g. Particularly preferably have and is greater than 100m²The high surface area inorganic oxide of the surface area of/g, such as high surface area alumina.Other are excellent The third inorganic oxide of choosing includes lanthanum/alumina composite oxide, optionally further includes zirconium component such as zirconium oxide.? In the case where in this way, zirconium be can reside on lanthanum/alumina composite oxide surface, such as coating.

Third OSC material and third inorganic oxide can have at least 1:1, preferably at least 2:1, more preferably at least 3:1 Weight ratio.

Alternatively, third OSC material and third inorganic oxide can have 10:1-1:10, preferably 8:1-1:8 or 5:1- 1:5, the weight ratio of more preferable 4:1-1:4 or 3:1-1:3.

In some embodiments, the first palladium component and the second palladium component have the weight ratio of 50:1-1:50.Other In embodiment, the weight ratio of the first palladium component and the second palladium component with 30:1-1:30.In another embodiment, first Palladium component and the second palladium component have the weight ratio of 10:1-1:10.In yet another embodiment, the first palladium component and the second palladium group Divide the weight ratio with 5:1-1:5.

Preferably, the first palladium component and the second palladium component, which have, is greater than 1:1, more preferably at least 3:1 or 4:1, even more The preferably at least weight ratio of 5:1.

In some embodiments, third rhodium component and the first palladium component have the weight ratio of 60:1-1:60.Preferably, Third rhodium component and the first palladium component have the weight ratio of 40:1-1:40.It is highly preferred that third rhodium component and the first palladium component tool There is the weight ratio of 30:1-1:30.Most preferably, third rhodium component and the first palladium component have the weight ratio of 10:1-1:10.

The catalyst article of the utility model may include other components well known by persons skilled in the art.For example, this reality At least one binder and/or at least one surfactant can be further included with novel composition.It is bonded when existing When agent, preferably dispersible alumina binder.

Preferably, carrier is flow type material all in one piece.

Carrier lengths can be greater than 90mm.

Flow type monolith carrier has defines longitudinal the first face and the second face therebetween.Flow type monolith carrier has more A channel extended between the first face and second face.Multiple channels extend in the longitudinal direction, provide multiple inner surfaces and (such as limit The surface of the wall in each channel).Multiple channels each have the opening in the opening in the first face and in the second face.To avoid doubting Justice, flow type monolith carrier are not wall-flow filters.

First face is usually in the arrival end of carrier, and the second face is in the outlet end of carrier.

Channel can be constant width, and multiple channels each can have uniform channel width.

Preferably, with longitudinally perpendicular plane in, monolith carrier has 300-900 channel per square inch, preferably 400-800.For example, on the first face, the density of open first passage and closed second channel is per square inch 600-700 channel.Channel can have rectangle, square, circle, ellipse, triangle, hexagon or other geometries Cross section.

The carrier of monoblock type serves as the carrier for being used to support catalysis material.The suitable material for being used to form carrier includes ceramics Sample material, such as cordierite, silicon carbide, silicon nitride, zirconium oxide, mullite, spodumene, alumina silica, magnesia or silicon Sour zirconium or porous refractory metal.Such material is in this field in the application manufactured in multi-porous monolithic carrier with them It is well known.

It should be noted that flow-through monolith as described herein is single component (i.e. monolithic support).But, work as formation When discharge treating system, carrier used can be by sticking together multiple channels or passing through multiple lesser this paper institutes The carrier stated sticks together to be formed.The suitable shell and construction of such technology and discharge treating system is this field In it is well known.

In the embodiment that the catalyst article of the utility model includes ceramic monolith, which can be by any Suitable refractory material is made, the refractory material such as aluminium oxide, silica, cerium oxide, zirconium oxide, magnesia, zeolite, nitrogen SiClx, silicon carbide, zirconium silicate, magnesium silicate, aluminosilicate and metal aluminosilicates (such as cordierite and spodumene) or its The arbitrarily mixture or mixed oxide of two or more.Particularly preferred cordierite, Almasilate and silicon carbide.

In the embodiment that the catalyst article of the utility model includes metallic carrier, which can be by any Suitable metal, especially heating resisting metal and metal alloy are made, the heating resisting metal and metal alloy such as titanium and stainless steel with And there are also the Alfers of other trace metals containing iron, nickel, chromium and/or aluminium.

In some embodiments, the first catalysis region can be loaded directly/is deposited on carrier.In certain embodiments In, the second catalysis region can be loaded directly/is deposited on carrier.

Catalytic converter equipped with TWC according to the present utility model shows that (PGM having the same is negative with routine TWC Carrying capacity) improvement compared, and particularly illustrate improved performance and better THC ignition performance in cold-start phase (such as Referring to Examples 1 and 2 and table 1 and 2).

The another aspect of the utility model is related to the system for handling vehicle exhaust, which includes as described herein urge Agent product, together with the exhaust pipe for the exhaust gas to be conveyed to the system.

Definition

Terms used herein " region " refer to a range on carrier, usually pass through dry and/or calcinated support Coating obtains.It is located at or is supported on carrier for example, " region " can be used as " floor " or " area ".It is administered to by carrier coating In the technical process of carrier, range or arrangement on carrier are generally controlled." region " usually have clearly boundary or Edge (can use conventional analytical techniques to distinguish a region and another region).

In general, " region " has substantial uniform length." the substantial uniform length " referred in this paper context It refers to and its average value deviates (such as difference of minimum and maximum length) no more than 10%, be preferably offset by no more than 5%, it is more excellent Choosing, which deviates, is not more than 1%.

Preferably, each " region " has substantially uniform composition (i.e. when by a part in region and the region When another part is compared, do not have tangible difference on the composition of carrier coating).It is substantial uniform in this paper context Composition refers to that difference when a part in region to be compared with the another part in the region, on composition is 5% or more It is small, often 2.5% or smaller, most commonly 1% or smaller material (such as region).

Terms used herein " area " refer to that length is less than carrier total length, 75% area of such as≤carrier total length Domain.The length (i.e. substantial uniform length) of " area " usually at least 5% (such as >=5%) with carrier total length.

Carrier total length is the distance between its arrival end and its outlet end (such as opposite end of carrier).

Referring to " positioned at the area at carrier inlet end " of mentioning in use herein is located at or loads area on this carrier, In compared with the area and carrier outlet end, the area is closer to carrier inlet end.So compared with midpoint (i.e. its length in the area Half) with carrier outlet end, the midpoint is closer to carrier inlet end.Similarly, that mentions in use herein " goes out positioned at carrier The area at mouthful end " refers to being located at or loading area on this carrier, wherein compared with the area and carrier inlet end, the area closer to Carrier outlet end.So the midpoint is closer to carrier compared with the midpoint (i.e. the half of its length) and carrier inlet end in the area Outlet end.

When carrier be wall-flow filter when, then generally mention refer to being located at " positioned at the area at carrier inlet end " or The area of load on this carrier:

(a) compared with the area and the access road of the carrier closed end (such as occlusion or blocking end), closer to The arrival end (such as open end) of the access road, and/or

(b) compared with the outlet end (such as open end) in the area and the exit passageway of the carrier, closer to the exit passageway Closed end (such as occlusion or blocking end).

So closing of the midpoint (i.e. the half of its length) (a) in the area compared with the midpoint and the access road of the carrier End, closer to the arrival end of the access road, and/or (b) compared with the outlet end at the midpoint and the exit passageway of the carrier, more Close to the closed end of the exit passageway.

Similarly, when carrier is wall-flow filter, then that generally mentions refers to " positioned at the area at carrier outlet end " It is the area for being located at or loading on this carrier:

(a) compared with the closed end (such as occlusion or blocking) of the area and the exit passageway of the carrier, closer to this The outlet end (such as open end) of exit passageway, and/or

(b) compared with the arrival end (such as open end) of it and the access road of the carrier, closer to the access road Closed end (such as occlusion or blocking end).

So closing of the midpoint (i.e. the half of its length) (a) in the area compared with the midpoint and the exit passageway of the carrier End, closer to the outlet end of the exit passageway, and/or (b) compared with the arrival end at the midpoint and the access road of the carrier, more Close to the closed end of the access road.

When (i.e. area is in wall) in the wall that carrier coating is present in wall-flow filter, which can satisfy (a) and (b) The two.

Term " carrier coating " is it is well known in the art that referring to usually being administered to carrier in production catalyst process Adhesive coatings.

Abbreviation " PGM " used herein refers to " platinum group metal ".Term " platinum group metal " refer generally to selected from Ru, The metal of Rh, Pd, Os, Ir and Pt are preferably selected from the metal of Ru, Rh, Pd, Ir and Pt.Generally speaking, term " PGM " is preferred Refer to the metal selected from Rh, Pt and Pd.

Terms used herein " mixed oxide " refer generally to the hopcalite of single-phase, such as this field In it is conventionally known.Terms used herein " composite oxides " refer generally to the group with the oxide more than a phase Object is closed, as conventionally known in this field.

Expression " mainly by ... form " used herein by characteristic range be limited to include the material specified or step with The not any other materials or step of the fundamental characteristics of materially affect this feature, such as a small amount of impurity.Expression is " mainly by ... group At " include expression " by ... form ".

Usually in the context of the content in region, the area Ceng Huo, the expression " being generally free of " herein for materials'use is anticipated Think of is that the material is a small amount of, such as≤5wt%, preferably≤2wt%, more preferably≤1wt%.Expression is included in expression " being generally free of " " not including ".

Usually in the context of the content in region, the area Ceng Huo, anticipate herein for the expression substantially free of materials'use Think of is that the material is trace, such as≤1wt%, preferably≤0.5wt%, more preferably≤0.1wt%.Expression substantially free is included It expresses " not including ".

Herein in use any doped chemical referred to amount, especially total amount indicates with wt%, refers to carrier material Or the weight of its refractory metal oxide.

Terms used herein " load capacity " refer to the measurement based on weight metal, unit g/ft³。

Following embodiment only illustrates the utility model.Those skilled in the art will appreciate that the utility model purport and right Many variations within the scope of claim.

Embodiment

Material

All material is commercially available and obtains from known suppliers, unless otherwise noted.

Catalyst A:

First catalysis region:

First catalysis region is supported on by Pd by the first CeZr mixed oxide, the stabilized aluminium oxide of La and Ba auxiliary agent group At coating in.Carrying capacity is about 1.7g/in on the coating of first catalysis region³, wherein Pd load capacity is 200g/ft³。

Then, using standard application program, by the carrier coating from ceramic monolith (750 hole densities, 2.5mil wall thickness) Inlet face coating, target coat depth is the 50% of carrier lengths, in 90 DEG C of dryings.

Second catalysis region:

Second catalysis region is supported on by Pd by the 2nd CeZr mixed oxide, the stabilized aluminium oxide of La and Ba auxiliary agent group At coating in.Carrying capacity is about 1.7g/in on the coating of second catalysis region³, wherein Pd load capacity is 34g/ft³。

Then, using standard application program, by Second support coating from the ceramic monolith containing the first catalysis region For exit face from upper coating, target coat depth is the 50% of carrier lengths, is calcined 45 minute in 90 DEG C of dryings and at 500 DEG C.

Third catalysis region:

Third catalysis region is supported on by Rh and is made of the 3rd CeZr mixed oxide and the stabilized aluminium oxide of La.Third Carrying capacity is about 1.3g/in on the coating of catalysis region³, wherein Rh load capacity is 8g/ft³。

Then, using standard application program, by third carrier coating from the ceramics containing the first and second catalysis regions For the exit face of carrier from upper coating, target coat depth is the 90% of carrier lengths, in 90 DEG C of dryings and calcines 45 points at 500 DEG C Clock.

Comparative catalyst B:

Comparative catalyst B is prepared according to the program similar with catalyst A, in addition to the third in comparative catalyst B to be catalyzed The whole length (i.e. 100%) of region coating carrier.Total Pd load capacity is 117g/ft³, and total Rh load capacity is 8g/ft³。

Comparative catalyst C:

Comparative catalyst C is business triple effect (Pd-Rh) catalyst with double-layer structure.Bottom is supported on by Pd by first In the coating of the stabilized aluminium oxide of CeZr mixed oxide, La and Ba auxiliary agent composition.The coating load amount of bottom is about 1.7g/ in³, wherein Pd load capacity is 117g/ft³.Upper layer is supported on the 2nd CeZr mixed oxide and the stabilized aluminium oxide of La by Rh Composition.Carrying capacity is about 1.3g/in on the coating on upper layer³, wherein Rh load capacity is 8g/ft³.Carrying capacity is on total coating of catalyst C About 3.0g/in³。

Catalyst D

Catalyst D is prepared according to the program similar with catalyst A, in addition to replacing 50% with Sr in the first catalysis region Ba auxiliary agent.

Catalyst E

Catalyst E is prepared according to the program similar with catalyst A, in addition to replacing 100% with Sr in the first catalysis region Ba auxiliary agent.

Embodiment 1: vehicle testing program and result

With new European test loop (NEDC), catalyst A and comparative catalyst B is tested on the vehicle of 1.5 liters of engines With the fresh performance of comparative catalyst C.Show that the bag from offgas duct adopts data (bag data) in table 1.The utility model Catalyst A compared with comparative catalyst B and C, provide significant lower THC, CO and NO_xDischarge (for example, with reference to when urging Respectively to THC, CO and NO when agent A is compared with comparative catalyst B_xThe correlation of discharge about 20%, 10% and 24% It can improve).

1 vehicle of table dilution bag adopts emission data

In addition, the catalyst A of the utility model is provided compared with comparative catalyst B and C as shown in Fig. 4 a, 4b and 4c In the significantly improved emission control performance of cold-start phase.Show that drive cycle is initial 30 seconds, 50 seconds, 100 seconds in table 2 Accumulative emissions data is summarized.

Accumulative exhaust emissions result of the table 2 in cold-start phase

Embodiment 2: the ignition performance test in Engine Block Test

Test catalyst A and comparative catalyst B respectively on gasoline engine.Ignition test is representative condition, and extraction flow is 80kg/ hours, heating rate was 30 DEG C/min, and the λ of air-fuel ratio (AFR) is 14.55.From to feed gas and catalyst outlet The concentration of gas is compared to calculate THC, CO and NO_xConversion ratio.Before the test of engine ignition, by catalyst A and Comparative catalyst B is in identical operating, under 6.1L engine, start within 100 hours with four operating condition standard ageing cycles Machine frame senile experiment, the peak value bed temperature of catalyst are about 980 DEG C.

THC, CO and NO of catalyst A and comparative catalyst B are shown in table 3_xT₅₀Initiation temperature.Data are surprisingly It points out, when compared with the double-deck example with comparative catalyst B, the multi-region catalyst A of the utility model provides significantly improved Ignition performance, low about 20 DEG C of T₅₀(T₅₀For the temperature when conversion ratio reaches 50%).

3 engine experimental table ignition test result of table

Embodiment 3: vehicle testing program and result

With new European test loop (NEDC), catalyst A, catalyst D and catalysis are tested on the vehicle of 1.5 liters of engines The exemplar through rack aging of agent E.Rack aging is in identical operating, under 6.1L engine, is followed with four operating condition standard agings Ring carries out 150 hours engine pedestal senile experiments, and the peak value bed temperature of catalyst is about 980 DEG C.It shows in table 4 from whole The exhaust pipe dilution bag of vehicle adopts data result.The catalyst D and catalyst E of the utility model are provided very compared with catalyst A To lower THC, CO and NO_xDischarge (for example, with reference to when catalyst E is compared with catalyst A respectively to THC, CO and NO_xThe correlated performance of discharge about 26%, 18% and 14% improves).

Table 4 dilutes bag by vehicle and adopts emission result

Claims (14)

1. the catalyst article for handling gasoline exhaust, it includes:

Including arrival end, outlet end and the carrier with axial length L；

Start from the arrival end and extend less than the first catalysis region of the axial length L, wherein first catalysis region includes First palladium component；

Start from the outlet end and extend less than the second catalysis region of the axial length L, wherein second catalysis region includes Second palladium component；

Start from the outlet end and extend less than the third catalysis region of the axial length L, wherein the third catalysis region includes Third rhodium component；With

Wherein the third catalysis region is stacked on second catalysis region and extends the 50-95% of the axial length L.

2. catalyst article according to claim 1, wherein first catalysis region extends the 30- of the axial length L 70%.

3. catalyst article according to claim 1 or 2, wherein second catalysis region extends the 30- of the axial length L 70%.

4. catalyst article according to claim 1 or 2, wherein second catalysis region is Chong Die with first catalysis region The 1-15% of the axial length L.

5. catalyst article according to claim 1 or 2, wherein second catalysis region and first catalysis region is total Length is equal to the axial length L.

6. catalyst article according to claim 1 or 2, wherein second catalysis region and first catalysis region is total Length is less than the axial length L.

7. catalyst article according to claim 1 or 2, wherein first catalysis region includes 0.1-300g/ft³Should First palladium component.

8. catalyst article according to claim 1 or 2, wherein second catalysis region includes 0.1-50g/ft³This Two palladium components.

9. catalyst article according to claim 1 or 2, wherein the third catalysis region includes 0.1-20g/ft³This Three rhodium components.

10. catalyst article according to claim 1 or 2, wherein the carrier is flow type material all in one piece.

11. catalyst article according to claim 1 or 2, wherein the carrier lengths are greater than 90mm.

12. catalyst article according to claim 1 or 2, wherein first catalysis region directly loads/is deposited on the load On body.

13. catalyst article according to claim 1 or 2, wherein second catalysis region directly loads/is deposited on the load On body.

14. being used for the discharge treating system for the treatment of of combustion flue gas stream, it includes according to claim 1 to 13 Catalyst article.