Exhaust gas treatment system for treating the exhaust gas flow exiting a gasoline engine

Abstract

The present invention relates to an exhaust gas treatment system for treating an exhaust gas flow exiting a gasoline engine, the system comprising a first catalyst, namely a three-way conversion catalyst, a second catalyst, namely a four-way conversion catalyst, and a third catalyst comprising an SCR coating. The present invention further relates to a method for treating an exhaust gas flow exiting a gasoline engine using the exhaust gas treatment system.

Description

Technical Field

[0001] The present invention relates to an exhaust gas treatment system for treating an exhaust gas stream exiting a gasoline engine, and a method for treating an exhaust gas stream exiting a gasoline engine using the exhaust gas treatment system.

Background Art

[0002] Emission regulations for exhaust gases from automotive gasoline applications have been becoming increasingly stringent, and will likely lead to even more stringent regulations in the future. Therefore, more effective exhaust gas treatment systems for automobiles will be required in the coming years. Efficient methods for removing the main pollutants including nitrogen oxides (NOx), unburned hydrocarbons (HC), carbon monoxide (CO), and particulate matter from gasoline engines have been developed and commercialized based on so-called three-way conversion (TWC) or four-way conversion (FWC) catalysts.

[0003] However, future emission regulations may also impose more stringent restrictions on secondary emissions from exhaust gases. For example, more stringent European emission standards such as EURO 7 or equivalent regulations in the United States may impose restrictions on tailpipe emissions of ammonia (NH3), hydrocarbons (HC), and carbon monoxide (CO).

[0004] Research has shown that such components have harmful effects on humans, ecosystems, and plants. Therefore, there is a need to provide an improved exhaust gas treatment system that enables reduction of tailpipe emissions of ammonia (NH3), hydrocarbons (HC), and carbon monoxide (CO).

[0005] Accordingly, an object of the present invention is to provide an improved exhaust gas treatment system for treating an exhaust gas stream exiting a gasoline engine, which is capable of reducing tailpipe emissions of ammonia (NH3), hydrocarbons (HC) and / or carbon monoxide (CO) compared to prior art systems such as EURO 6 or other systems. In addition to improved ammonia tailpipe emissions, the system of the present invention has been found to significantly contribute to HC emission reduction mainly due to robust low temperature HC light-off activity. Summary of the Invention

[0006] Accordingly, the present invention relates to an exhaust gas treatment system for treating an exhaust gas stream exiting a gasoline engine, the exhaust gas treatment system having an upstream end for introducing the exhaust gas stream into the exhaust gas treatment system, the exhaust gas treatment system comprising: (i) a three-way conversion catalyst, a first catalyst having an inlet end and an outlet end and including a coating disposed on a substrate, the coating including a platinum group metal component supported on a porous oxide material, the first catalyst; (ii) a four-way conversion catalyst, a second catalyst having an inlet end and an outlet end and including a coating disposed on a wall flow filter substrate, the coating including a platinum group metal component supported on a porous oxide material, the second catalyst; (iii) a third catalyst having an inlet end and an outlet end, the third catalyst including a substrate and a coating for selective catalytic reduction of NOx, the SCR coating including a zeolite material containing one or more of Fe and Cu, and up to 0.0001 wt% of the SCR coating consisting of a platinum group metal, the third catalyst; (i) the first catalyst is the first catalyst of the exhaust gas treatment system downstream of the upstream end of the exhaust gas treatment system, and the inlet end of the first catalyst is disposed upstream of the outlet end of the first catalyst; In an exhaust gas treatment system, the second catalyst according to (ii) is positioned downstream of the first catalyst according to (i), and the inlet end of the second catalyst is disposed upstream of the outlet end of the second catalyst. In an exhaust gas treatment system, the third catalyst according to (iii) is positioned downstream of the second catalyst according to (ii), and the inlet end of the third catalyst is disposed upstream of the outlet end of the third catalyst.

[0007] Preferably, the outlet end of the first catalyst according to (i) is in fluid communication with the inlet end of the second catalyst according to (ii), and there is no catalyst for treating the exhaust gas flow exiting the first catalyst positioned within the exhaust gas treatment system between the outlet end of the first catalyst according to (i) and the inlet end of the second catalyst according to (ii).

[0008] Preferably, the outlet end of the second catalyst according to (ii) is in fluid communication with the inlet end of the third catalyst according to (iii), and there is no catalyst for treating the exhaust gas flow exiting the second catalyst positioned within the exhaust gas treatment system between the outlet end of the second catalyst according to (ii) and the inlet end of the third catalyst according to (iii).

[0009] The first catalyst Preferably, the platinum group metal component of the coating of the first catalyst comprises one or more of Pd, Rh, and Pt, more preferably one or more of Pd and Rh, and even more preferably Pd and Rh.

[0010] Preferably, the coating of the first catalyst contains the platinum group metal component in a loading range of 1 - 200 g / ft 3 in the range, more preferably 20 - 180 g / ft 3 in the range, and even more preferably 50 - 150 g / ft 3 in the range.

[0011] Preferably, the porous oxide material supporting the platinum group metal component of the coating of the first catalyst is selected from the group consisting of alumina, ceria, silica, zirconia, titania, mixtures of two or more thereof, and mixed oxides of two or more thereof, more preferably selected from the group consisting of alumina, titania, zirconia, mixtures of two or more thereof, and mixed oxides of two or more thereof, more preferably selected from the group consisting of alumina, zirconia, mixtures of these two, and mixed oxides of these two, and even more preferably alumina.

[0012] Preferably, the first catalyst contains the porous oxide material of the coating in an amount in the range of 0.2 to 4.0 g / in 3 more preferably in the range of 0.3 to 3.0 g / in 3 more preferably in the range of 0.4 to 2.5 g / in 3 even more preferably in the range of 0.5 to 2.0 g / in 3 of the coating.

[0013] Preferably, the coating of the first catalyst further contains an oxygen storage component, and the oxygen storage component more preferably contains cerium, and more preferably contains one or more of cerium oxide, a mixture of oxides containing cerium, and a mixed oxide containing cerium. The mixed oxide containing cerium more preferably contains one or more of zirconium, yttrium, neodymium, lanthanum, hafnium, samarium, and praseodymium, more preferably one or more of zirconium, yttrium, neodymium, lanthanum, and praseodymium, and even more preferably further contains zirconium.

[0014] Preferably, the oxygen storage component of the coating of the first catalyst contains a mixed oxide containing cerium and zirconium.

[0015] Preferably, 95 to 100% by weight, more preferably 98 to 100% by weight, more preferably 99 to 100% by weight, and even more preferably 99.5 to 100% by weight of the oxygen storage component consists of a mixed oxide containing cerium and zirconium.

[0016] Preferably, 10 to 60% by weight, more preferably 20 to 60% by weight, even more preferably 20 to 50% by weight of the oxygen storage component consists of cerium calculated as CeO2, and preferably 20 to 90% by weight, more preferably 40 to 70% by weight, even more preferably 50 to 70% by weight of the oxygen storage component consists of zirconium calculated as ZrO2. Preferably, 0 to 20% by weight, more preferably 0 to 10% by weight of the OSC consists of lanthanum and yttrium calculated as La2O3 and Y2O3.

[0017] Preferably, the coating of the first catalyst contains the oxygen storage component in an amount in the range of 0.3 to 5 g / in 3 more preferably in the range of 0.4 to 3.5 g / in 3 more preferably in the range of 0.45 to 3.0 g / in 3 more preferably in the range of 0.5 to 2.5 g / in 3 and is included in the range of the loading amount.

[0018] Preferably, in the coating of the first catalyst, the weight ratio of the porous oxide material to the oxygen storage component defined above is in the range of 1:1 to 10:1, more preferably in the range of 1:1 to 5:1.

[0019] In the context of the present invention, it is conceivable that the platinum group metal of the first catalyst is also supported on the oxygen storage component.

[0020] Preferably, the coating of the first catalyst further contains a non-zeolite oxide material, and the non-zeolite oxide material more preferably contains one or more of zirconia, alumina, ceria, titania, silica, and mixed oxides containing two or more of Zr, Al, Ce, Ti, and Si, more preferably contains one or more of silica, ceria, alumina, and zirconia, and more preferably contains zirconia.

[0021] Preferably, the coating of the first catalyst contains a non-zeolite oxide material in an amount in the range of 0.5 to 12% by weight, more preferably in the range of 1 to 10% by weight, and even more preferably in the range of 1 to 5% by weight, calculated as an oxide, based on the weight of the coating of the first catalyst.

[0022] Preferably, the coating of the first catalyst further contains an alkaline earth metal oxide, and the alkaline earth metal is more preferably selected from the group consisting of barium, strontium, and magnesium, even more preferably selected from the group consisting of barium and strontium, and even more preferably barium.

[0023] Preferably, the coating of the first catalyst contains an alkaline earth metal oxide in an amount in the range of 0.5 to 15% by weight, more preferably in the range of 1 to 10% by weight, and even more preferably in the range of 1 to 6% by weight, based on the weight of the coating of the first catalyst.

[0024] Preferably, the coating of the first catalyst contains a platinum group metal component supported on a porous oxide material, more preferably an oxygen storage component defined above, even more preferably a non-zeolite oxide material defined above, and even more preferably an alkaline earth metal oxide defined above.

[0025] Preferably, 98 to 100% by weight, more preferably 99 to 100% by weight, even more preferably 99.5 to 100% by weight, and even more preferably 99.9 to 100% by weight of the coating of the first catalyst is a platinum group metal component supported on a porous oxide material, more preferably an oxygen storage component defined above, even more preferably a non-zeolite oxide material defined above, and even more preferably an alkaline earth metal oxide defined above. More preferably, the coating of the first catalyst consists of a platinum group metal component supported on a porous oxide material, more preferably an oxygen storage component defined above, even more preferably a non-zeolite oxide material defined above, and even more preferably an alkaline earth metal oxide defined above.

[0026] Preferably, the substrate of the first catalyst is a flow-through substrate, more preferably a ceramic flow-through substrate.

[0027] Preferably, the ceramic substrate is made of any suitable refractory material, such as cordierite, cordierite-α-alumina, aluminum titanate, silicon titanate, silicon carbide, silicon nitride, zircon mullite, rhodonite, alumina-silica-magnesia, zircon silicate, sillimanite, magnesium silicate, zircon, petalite, α-alumina, aluminosilicate, etc.

[0028] Preferably, the first catalyst consists of a substrate and a coating.

[0029] Preferably, the coating of the first catalyst extends over 98 - 100% of the axial length of the substrate, more preferably over 99 - 100%, and even more preferably over 99.5 - 100%. The coating is preferably disposed on the substrate of the first catalyst.

[0030] Preferably, the first catalyst has a coating loading in the range of 1 - 7 g / in 3 more preferably in the range of 1.5 - 5 g / in 3 more preferably in the range of 2 - 3.5 g / in 3 and contains a coating with such a loading.

[0031] The second catalyst Preferably, the platinum group metal component of the coating of the second catalyst is one or more of Pd, Rh, and Pt, more preferably one or more of Pd and Rh, and even more preferably contains Pd and Rh.

[0032] Preferably, the coating of the second catalyst contains the platinum group metal component in a loading range of 1 - 100 g / ft 3 more preferably in the range of 3 - 80 g / ft 3 more preferably in the range of 4 - 50 g / ft 3 and contains such a loading.

[0033] Preferably, the porous oxide material carrying the platinum group metal component of the coating of the second catalyst is selected from the group consisting of alumina, ceria, silica, zirconia, titania, mixtures of two or more thereof, and mixed oxides of two or more thereof, more preferably selected from the group consisting of alumina, titania, zirconia, mixtures of two or more thereof, and mixed oxides of two or more thereof, more preferably selected from the group consisting of alumina, zirconia, mixtures of these two, and mixed oxides of these two, and even more preferably is alumina.

[0034] Preferably, the second catalyst contains the porous oxide material of the coating in an amount in the range of 0.5 to 2.5 g / in 3 more preferably in the range of 0.6 to 2.0 g / in 3 more preferably in the range of 0.7 to 1.5 g / in 3 more preferably in the range of 0.8 to 1.2 g / in 3 of the coating.

[0035] Preferably, the coating of the second catalyst further contains an oxygen storage component (OSC), and the oxygen storage component more preferably contains cerium, and more preferably contains one or more of cerium oxide, mixtures of oxides containing cerium, and mixed oxides containing cerium. The mixed oxide containing cerium more preferably contains one or more of zirconium, yttrium, neodymium, lanthanum, hafnium, samarium, and praseodymium, more preferably one or more of zirconium, yttrium, neodymium, lanthanum, and praseodymium, and even more preferably further contains zirconium.

[0036] Preferably, the oxygen storage component of the coating of the second catalyst contains a mixed oxide containing cerium and zirconium.

[0037] Preferably, 95 to 100 wt%, more preferably 98 to 100 wt%, more preferably 99 to 100 wt%, and even more preferably 99.5 to 100 wt% of the oxygen storage component consists of a mixed oxide containing cerium and zirconium.

[0038] Preferably, 10 to 60% by weight, more preferably 20 to 60% by weight, still more preferably 20 to 50% by weight of the oxygen storage component consists of cerium calculated as CeO2, and more preferably 20 to 90% by weight, more preferably 40 to 70% by weight, still more preferably 50 to 70% by weight of the oxygen storage component consists of zirconium calculated as ZrO2. Preferably 0 to 20% by weight, more preferably 0 to 10% by weight of the OSC consists of lanthanum and yttrium calculated as La2O3 and Y2O3. More preferably, the OSC contains lanthanum and yttrium in addition to cerium and zirconium.

[0039] Preferably, the coating of the second catalyst contains the oxygen storage component in an amount in the range of 1.5 to 2.5 g / in 3 in the range, more preferably 1.2 to 2.2 g / in 3 in the range, more preferably 1.0 to 2.0 g / in 3 in the range, more preferably 1 to 1.75 g / in 3 in the range of the supported amount.

[0040] Preferably, in the coating of the second catalyst, the weight ratio of the porous oxide material to the oxygen storage component defined above is in the range of 1:1 to 0.5:1, more preferably in the range of 1:1 to 0.25:1.

[0041] In the context of the present invention, it is conceivable that the platinum group metal of the first catalyst is also supported on the oxygen storage component.

[0042] Preferably, the coating of the second catalyst further contains a non-zeolite oxide material, and the non-zeolite oxide material more preferably contains one or more of zirconia, alumina, ceria, titania, silica, and mixed oxides containing two or more of Zr, Al, Ce, Ti, and Si, more preferably contains one or more of silica, ceria, alumina, and zirconia, and more preferably contains zirconia.

[0043] Preferably, the coating of the second catalyst contains a non-zeolite oxide material in an amount in the range of 0.5 to 12% by weight, more preferably in the range of 1 to 10% by weight, and still more preferably in the range of 1 to 5% by weight, calculated as an oxide, based on the weight of the coating of the first catalyst.

[0044] Preferably, the coating of the second catalyst further contains an alkaline earth metal oxide, and the alkaline earth metal is more preferably selected from the group consisting of barium, strontium, and magnesium, still more preferably selected from the group consisting of barium and strontium, and still more preferably barium.

[0045] Preferably, the coating of the second catalyst contains an alkaline earth metal oxide in an amount in the range of 0.5 to 15% by weight, more preferably in the range of 1 to 10% by weight, and still more preferably in the range of 1 to 6% by weight, based on the weight of the coating of the first catalyst.

[0046] Preferably, the coating of the second catalyst consists of a platinum group metal component supported on a porous oxide material, more preferably an oxygen storage component defined above, still more preferably a non-zeolite oxide material defined above, and still more preferably an alkaline earth metal oxide defined above.

[0047] Preferably, 98 to 100% by weight, more preferably 99 to 100% by weight, still more preferably 99.5 to 100% by weight, and still more preferably 99.9 to 100% by weight of the coating of the second catalyst consists of a platinum group metal component supported on a porous oxide material, more preferably an oxygen storage component defined above, still more preferably a non-zeolite oxide material defined above, and still more preferably an alkaline earth metal oxide defined above. More preferably, the coating of the second catalyst consists of a platinum group metal component supported on a porous oxide material, more preferably an oxygen storage component defined above, still more preferably a non-zeolite oxide material defined above, and still more preferably an alkaline earth metal oxide defined above.

[0048] Preferably, the substrate of the second catalyst is a ceramic wall flow filter substrate.

[0049] Preferably, the ceramic substrate is made of any suitable refractory material such as cordierite, cordierite-alpha-alumina, aluminum titanate, silicon titanate, silicon carbide, silicon nitride, zircon mullite, rhodonite, alumina-silica-magnesia, zircon silicate, sillimanite, magnesium silicate, zircon, petalite, alpha-alumina, aluminosilicate, etc.

[0050] Preferably, the second catalyst consists of a substrate and a coating.

[0051] Preferably, the coating of the second catalyst extends over 98 - 100%, preferably 99 - 100%, more preferably 99.5 - 100% of the axial length of the substrate. The coating is preferably disposed on the substrate of the second catalyst.

[0052] Preferably, the second catalyst has a coating loading in the range of 0.5 - 3 g / in 3 more preferably in the range of 0.75 - 2.5 g / in 3 more preferably in the range of 1.0 - 1.75 g / in 3 and includes a coating with a loading in the range of.

[0053] Preferably, there is no catalyst between the first catalyst according to (i) and the second catalyst according to (ii). In fact, it is preferred that there is no other catalyst between the three-way conversion catalyst according to (i) and the four-way conversion catalyst according to (ii).

[0054] The third catalyst Preferably, the zeolite material included in the SCR coating of the third catalyst is a 12-membered ring pore zeolite material, and the 12-membered ring pore zeolite material is more preferably a framework type selected from the group consisting of BEA, MOR, FAU, GME, OFF, mixtures of two or more of them, and mixed types of two or more of them, more preferably a framework type selected from the group consisting of BEA, MOR, FAU, mixtures of two or more of them, and mixed types of two or more of them, more preferably a framework type selected from the group consisting of BEA and FAU. More preferably, the 12-membered ring pore zeolite material included in the SCR coating of the third catalyst has a framework type BEA.

[0055] Preferably, the zeolite material included in the SCR coating of the third catalyst is a 12-membered ring pore zeolite material, the zeolite material contains Fe, and the 12-membered ring pore zeolite material is more preferably a framework type selected from the group consisting of BEA, MOR, FAU, GME, OFF, mixtures of two or more of them, and mixed types of two or more of them, more preferably a framework type selected from the group consisting of BEA, MOR, FAU, mixtures of two or more of them, and mixed types of two or more of them, more preferably a framework type selected from the group consisting of BEA and FAU. More preferably, the 12-membered ring pore zeolite material included in the SCR coating of the third catalyst has a framework type BEA.

[0056] Preferably, 95 to 100% by weight, more preferably 98 to 100% by weight, more preferably 99 to 100% by weight, more preferably 99.5 to 100% by weight of the framework structure of the 12-membered ring pore zeolite material included in the SCR coating of the third catalyst consists of Si, Al, and O. In the framework structure, the molar ratio of Si to Al calculated as molar SiO2:Al2O3 is more preferably in the range of 2:1 to 40:1, more preferably in the range of 3:1 to 30:1, more preferably in the range of 4:1 to 20:1, more preferably in the range of 6:1 to 15:1.

[0057] Preferably, the zeolite material contained in the SCR coating of the third catalyst contains iron, and the amount of iron contained in the zeolite material, calculated as Fe2O3, is more preferably in the range of 0.1 to 10.0% by weight, more preferably in the range of 0.5 to 8% by weight, and more preferably in the range of 1.5 to 7.5% by weight based on the total weight of the zeolite material.

[0058] Preferably, the zeolite material does not contain Cu.

[0059] Preferably, the SCR coating of the third catalyst further contains a non-zeolite oxide material, and the non-zeolite oxide material more preferably contains one or more of zirconia, alumina, ceria, titania, silica, and mixed oxides containing two or more of Zr, Al, Ce, Ti, and Si, and more preferably contains one or more of zirconia, alumina, ceria, and silica.

[0060] Preferably, the SCR coating of the third catalyst contains the non-zeolite oxide material in an amount in the range of 0.5 to 12% by weight, more preferably in the range of 1 to 10% by weight, and more preferably in the range of 1 to 6% by weight, calculated as an oxide, based on the weight of the SCR coating of the third catalyst.

[0061] Preferably, at most 0.00001% by weight of the SCR coating of the third catalyst consists of platinum group metals, and more preferably, 0 to 0.00001% by weight of the SCR coating of the third catalyst consists of platinum group metals.

[0062] In other words, preferably, the coating of the third catalyst does not substantially contain platinum group metals, and more preferably does not contain them.

[0063] Preferably, the substrate of the third catalyst is a flow-through substrate, and more preferably a ceramic flow-through substrate.

[0064] Preferably, the ceramic substrate is made of any suitable refractory material, such as cordierite, cordierite-alpha-alumina, aluminum titanate, silicon titanate, silicon carbide, silicon nitride, zircon mullite, hedenbergite, alumina-silica-magnesia, zircon silicate, sillimanite, magnesium silicate, zircon, petalite, alpha-alumina, aluminosilicate, etc.

[0065] Preferably 98 to 100% by weight, more preferably 99 to 100% by weight, more preferably 99.5 to 100% by weight, and more preferably 99.9 to 100% by weight of the SCR coating of the third catalyst comprises a zeolite material containing one or more of Fe and Cu, and more preferably consists of the non-zeolite oxide material defined above.

[0066] -Third catalyst: SCR catalyst Preferably, the third catalyst consists of a substrate and an SCR coating.

[0067] Preferably, the SCR coating of the third catalyst extends over 98 to 100% of the axial length of the substrate, more preferably over 99 to 100%, and more preferably over 99.5 to 100%. The SCR coating is preferably disposed on the substrate of the third catalyst.

[0068] Preferably, the SCR coating contains a zeolite material, more preferably consists of a zeolite material, the zeolite material more preferably has a framework type BEA, and contains iron and a non-zeolite oxide material, more preferably zirconia.

[0069] -Third catalyst: SCR / AMOx layered catalyst Preferably, the third catalyst includes an ammonia oxidation catalyst (AMOx) coating in addition to the SCR coating.

[0070] a) SCR coating Preferably, the SCR coating of the third catalyst is as defined above.

[0071] Preferably, the SCR coating of the third catalyst contains a zeolite material, more preferably consists of a zeolite material, and the zeolite material preferably has a framework type BEA and contains iron and a non-zeolite oxide material, more preferably ceria.

[0072] The proportion of the components of the SCR coating is preferably the same as that defined above for the third catalyst.

[0073] b) AMOx coating Preferably, the AMOx coating of the third catalyst contains one or more of platinum group metals, more preferably one or more of Pt, Pd and Rh, more preferably one or more of Pt and Pd, and more preferably Pt.

[0074] Preferably, the AMOx coating of the third catalyst contains the platinum group metal in a range of 1 to 20 g / ft 3 in terms of elemental platinum group metal, more preferably in a range of 2 to 10 g / ft 3 and more preferably in a range of 3 to 5 g / ft 3 in terms of the supported amount.

[0075] Preferably, the AMOx coating of the third catalyst contains a porous oxide material, more preferably a porous oxide material for supporting the platinum group metal, more preferably platinum, as defined above herein.

[0076] Preferably, the porous oxide material is selected from the group consisting of titania, alumina, ceria, silica, zirconia, mixtures of two or more thereof and mixed oxides of two or more thereof, preferably selected from the group consisting of titania, alumina and silica, and more preferably titania.

[0077] Preferably, the AMOx coating of the third catalyst contains the porous oxide material in an amount in the range of 0.25 to 3 g / in 3 and more preferably in a range of 0.5 to 1.5 g / in 3 in terms of the amount.

[0078] Preferably, the AMOx coating of the third catalyst further comprises a zeolite material containing one or more of Fe and Cu, more preferably a zeolite material containing Fe.

[0079] Preferably, the zeolite material of the AMOx coating of the third catalyst is a 12-membered ring pore zeolite material, and the 12-membered ring pore zeolite material is more preferably a framework type selected from the group consisting of BEA, MOR, FAU, GME, OFF, a mixture of two or more of them, and a mixed type of two or more of them, more preferably a framework type selected from the group consisting of BEA, MOR, FAU, a mixture of two or more of them, and a mixed type of two or more of them, more preferably a framework type selected from the group consisting of BEA and FAU. More preferably, the zeolite material of the AMOx coating of the third catalyst is a zeolite material having a framework type BEA.

[0080] Preferably, 95 to 100% by weight, more preferably 98 to 100% by weight, more preferably 99 to 100% by weight, more preferably 99.5 to 100% by weight of the framework structure of the 12-membered ring pore zeolite material contained in the AMOx coating of the third catalyst consists of Si, Al, and O.

[0081] Preferably, in the framework structure of the zeolite material, the molar ratio of Si to Al calculated as molar SiO2:Al2O3 is more preferably in the range of 2:1 to 40:1, more preferably in the range of 3:1 to 30:1, more preferably in the range of 4:1 to 20:1, more preferably in the range of 6:1 to 15:1.

[0082] Preferably, the zeolite material contained in the AMOx coating of the third catalyst contains iron, and the amount of iron contained in the zeolite material, calculated as Fe2O3, is more preferably in the range of 0.1 to 15.0% by weight, more preferably in the range of 0.5 to 10.0% by weight, more preferably in the range of 1.5 to 7.5% by weight based on the total weight of the zeolite material.

[0083] Preferably, in the AMOx coating, the weight ratio of the zeolite material containing one or more of Fe and Cu to the porous oxide material defined above is in the range of 0.5:1 to 2:1, more preferably in the range of 0.75:1 to 1.5:1, and even more preferably in the range of 1:1 to 1.25:1.

[0084] Preferably, the AMOx coating further contains a non-zeolite oxide material, and the non-zeolite oxide material preferably contains one or more of zirconia, alumina, ceria, titania, silica, and mixed oxides containing two or more of Zr, Al, Ce, Ti, and Si, more preferably contains one or more of silica, ceria, alumina, and zirconia, and even more preferably contains silica.

[0085] Preferably, the AMOx coating of the third catalyst contains the non-zeolite oxide material in an amount in the range of 0.5 to 18% by weight, more preferably in the range of 5 to 16% by weight, and even more preferably in the range of 8 to 13% by weight, calculated as the oxide, based on the weight of the coating of the third catalyst.

[0086] Preferably, the AMOx coating of the third catalyst contains the platinum group metal defined above, the porous oxide material supporting the platinum group metal defined above, the zeolite material containing one or more of Fe and Cu defined by any one of the above, and preferably the non-zeolite oxide material defined above.

[0087] Preferably, 98 to 100 wt%, more preferably 99 to 100 wt%, more preferably 99.5 to 100 wt%, more preferably 99.9 to 100 wt% of the AMOx coating of the third catalyst consists of the platinum group metal defined above, the porous oxide material supporting the platinum group metal defined above, the zeolite material containing one or more of Fe and Cu defined by any one of the above, and preferably the non-zeolite oxide material defined above. More preferably, the AMOx coating of the third catalyst consists of the platinum group metal defined above, the porous oxide material supporting the platinum group metal defined above, the zeolite material containing one or more of Fe and Cu defined by any one of the above, and preferably the non-zeolite oxide material defined above.

[0088] Preferably, the AMOx coating is disposed on the substrate of the third catalyst over 98 to 100%, preferably 99 to 100%, more preferably 99.5 to 100% of the axial length of the substrate, and the SCR coating is disposed on the AMOx coating over 98 to 100%, preferably 99 to 100%, more preferably 99.5 to 100% of the axial length of the substrate.

[0089] - Third catalyst: SCR / AMOx zone-forming catalyst Preferably, the third catalyst includes an inlet zone including, more preferably consisting of, an SCR coating, and an outlet zone including, more preferably consisting of, an ammonia oxidation catalyst coating.

[0090] Preferably, the inlet zone extends over x% of the axial length of the substrate from the inlet end to the outlet end of the substrate, where x is in the range of 20 to 60, more preferably in the range of 30 to 55, more preferably in the range of 45 to 55.

[0091] Preferably, the outlet zone extends over y% (y = 100 - x) of the axial length of the substrate from the outlet end to the inlet end of the substrate.

[0092] Preferably, the SCR coating is disposed on the substrate of the third catalyst over 50% of the axial length of the substrate to form an inlet zone. Preferably, the AMOx coating is disposed on the substrate of the third catalyst over 50% of the axial length of the substrate.

[0093] a) Inlet zone: SCR coating Preferably, the SCR coating in the inlet zone contains a zeolite material, more preferably consists of a zeolite material, the zeolite material more preferably has a framework type BEA, contains iron and a non-zeolite oxide material, and more preferably the non-zeolite material is a mixture of silica and alumina.

[0094] The components and proportions of the SCR coating are preferably as defined above.

[0095] b) Outlet zone: AMOx coating Preferably, the AMOx coating in the outlet zone - a first coat comprising a platinum group metal supported on a porous oxide material and a zeolite material containing one or more of Fe and Cu; - a second coat comprising a zeolite material containing one or more of Fe and Cu, with a maximum of 0.0001% by weight of the first coat consisting of a platinum group metal. The first coat is disposed on the substrate over the length of the outlet zone, and the second coat is disposed on the first coat over the length of the outlet zone, or The second coat is disposed on the substrate over the length of the outlet zone, and the first coat is disposed on the second coat over the length of the outlet zone.

[0096] Preferably, the first coat is disposed on the substrate over the length of the outlet zone, and the second coat is disposed on the first coat over the length of the outlet zone.

[0097] Preferably, the zeolite material of the second coat of the AMOx coating of the third catalyst is a 12-membered ring pore zeolite material, and the 12-membered ring pore zeolite material is more preferably a framework type selected from the group consisting of BEA, MOR, FAU, GME, OFF, a mixture of two or more of them, and a mixed type of two or more of them, more preferably a framework type selected from the group consisting of BEA, MOR, FAU, a mixture of two or more of them, and a mixed type of two or more of them, more preferably a framework type selected from the group consisting of BEA and FAU, and more preferably, the 12-membered ring pore zeolite material contained in the AMOx coating of the third catalyst has a framework type of BEA.

[0098] Preferably, 95 to 100% by weight, more preferably 98 to 100% by weight, more preferably 99 to 100% by weight, more preferably 99.5 to 100% by weight of the framework structure of the 12-membered ring pore zeolite material contained in the second coat of the AMOx coating of the third catalyst consists of Si, Al, and O.

[0099] Preferably, in the framework structure of the zeolite material, the molar ratio of Si to Al calculated as molar SiO2:Al2O3 is more preferably in the range of 2:1 to 40:1, more preferably in the range of 3:1 to 30:1, more preferably in the range of 4:1 to 20:1, more preferably in the range of 6:1 to 15:1.

[0100] Preferably, the zeolite material contained in the second coat of the AMOx coating of the third catalyst contains iron, and the amount of iron contained in the zeolite material is calculated as Fe2O3 and is more preferably in the range of 0.1 to 15.0% by weight, more preferably in the range of 1.0 to 10.0% by weight, more preferably in the range of 3.0 to 7.5% by weight based on the total weight of the zeolite material.

[0101] Preferably, at most 0.00001% by weight of the second coat of the AMOx coating of the third catalyst consists of a platinum metal component, and more preferably, 0 to 0.00001% by weight of the second coat of the AMOx coating of the third catalyst consists of a platinum group metal component.

[0102] In other words, preferably, the second coat of the AMOx coating of the third catalyst substantially does not contain a platinum group metal, and more preferably, does not contain a platinum group metal.

[0103] Preferably, the second coat of the AMOx coating of the third catalyst further contains a non-zeolite oxide material, and the non-zeolite oxide material more preferably contains one or more of zirconia, alumina, ceria, titania, silica, and mixed oxides containing two or more of Zr, Al, Ce, Ti, and Si, more preferably contains one or more of zirconia, alumina, ceria, and silica, and more preferably contains ceria.

[0104] Preferably, the second coat of the AMOx coating of the third catalyst contains a non-zeolite oxide material, more preferably ceria, in an amount in the range of 0.5 to 12% by weight, more preferably in the range of 1 to 10% by weight, more preferably in the range of 1 to 6% by weight, more preferably in the range of 1 to 4% by weight, based on the weight of the second coat of the AMOx coating of the third catalyst, calculated as the oxide.

[0105] Preferably, the second coat of the AMOx coating of the third catalyst contains a zeolite material containing one or more of Fe and Cu, more preferably contains the non-zeolite oxide material defined above.

[0106] Preferably 98 to 100% by weight, more preferably 99 to 100% by weight, more preferably 99.5 to 100% by weight, more preferably 99.9 to 100% by weight of the second coat of the AMOx coating of the third catalyst consists of a zeolite material containing one or more of Fe and Cu, more preferably the non-zeolite oxide material defined above. More preferably, the second coat of the AMOx coating of the third catalyst consists of a zeolite material containing one or more of Fe and Cu, more preferably the non-zeolite oxide material defined above.

[0107] Preferably, the platinum group metal contained in the first coat of the AMOx coating of the third catalyst is one or more of Pt, Pd, and Rh, more preferably one or more of Pt and Pd, and even more preferably Pt.

[0108] Preferably, the first coat of the AMOx coating of the third catalyst contains the platinum group metal in the range of 1 to 20 g / ft 3 in terms of elemental platinum group metal, more preferably in the range of 2 to 10 g / ft 3 in terms of elemental platinum group metal, even more preferably in the range of 3 to 7.5 g / ft 3 in terms of elemental platinum group metal.

[0109] Preferably, the porous oxide material of the first coat of the AMOx coating of the third catalyst is selected from the group consisting of titania, alumina, ceria, silica, zirconia, mixtures of two or more thereof, and mixed oxides of two or more thereof, more preferably selected from the group consisting of titania, silica, and alumina, and even more preferably titania.

[0110] Preferably, the first coat of the AMOx coating of the third catalyst contains the porous oxide material in an amount in the range of 10 to 80% by weight, more preferably in the range of 30 to 70% by weight, and even more preferably in the range of 45 to 55% by weight, based on the weight of the first coat of the AMOx coating of the third catalyst.

[0111] Preferably, the zeolite material of the first coat of the AMOx coating of the third catalyst is preferably a 12-ring pore zeolite material, and the 12-ring pore zeolite material is more preferably a framework type selected from the group consisting of BEA, MOR, FAU, GME, OFF, mixtures of two or more thereof, and mixed types of two or more thereof, even more preferably a framework type selected from the group consisting of BEA, MOR, FAU, mixtures of two or more thereof, and mixed types of two or more thereof, and even more preferably a framework type selected from the group consisting of BEA and FAU, and even more preferably, the 12-ring pore zeolite material contained in the second coat of the AMOx coating of the third catalyst has a framework type of BEA.

[0112] Preferably, 95 to 100% by weight, more preferably 98 to 100% by weight, more preferably 99 to 100% by weight, more preferably 99.5 to 100% by weight of the framework structure of the 12-membered ring zeolite material contained in the first coat of the AMOx coating of the third catalyst consists of Si, Al, and O.

[0113] Preferably, in the framework structure of the zeolite material of the first coat, the molar ratio of Si to Al calculated as molar SiO2:Al2O3 is more preferably in the range of 2:1 to 40:1, more preferably in the range of 3:1 to 30:1, more preferably in the range of 4:1 to 20:1, more preferably in the range of 6:1 to 15:1.

[0114] Preferably, the zeolite material contained in the first coat of the AMOx coating of the third catalyst contains iron, and the amount of iron contained in the zeolite material, calculated as Fe2O3, is more preferably in the range of 1.0 to 15.0% by weight, more preferably in the range of 2.0 to 10.0% by weight, more preferably in the range of 3.0 to 7.5% by weight based on the total weight of the zeolite material.

[0115] Preferably, in the first coat of the AMOx coating of the third catalyst, the weight ratio of the zeolite material containing one or more of Fe and Cu to the porous oxide material is in the range of 0.25:1 to 2:1, more preferably in the range of 0.5:1 to 1:1.

[0116] Preferably, the first coat of the AMOx coating of the third catalyst further contains a non-zeolite oxide material, and the non-zeolite oxide material more preferably contains one or more of zirconia, alumina, ceria, titania, silica, and mixed oxides containing two or more of Zr, Al, Ce, Ti, and Si, more preferably contains one or more of zirconia, alumina, ceria, and titania, and more preferably contains silica.

[0117] Preferably, the first coat of the AMOx coating of the third catalyst contains a non-zeolite oxide material in an amount in the range of 0.5 to 18% by weight, more preferably in the range of 5 to 16% by weight, and still more preferably in the range of 8 to 13% by weight, calculated as an oxide, based on the weight of the first coat of the AMOx coating of the third catalyst.

[0118] Preferably, the first coat of the AMOx coating of the third catalyst contains a zeolite material containing one or more of a platinum group metal, Fe, and Cu supported on a porous oxide material, more preferably a non-zeolite oxide material as defined above.

[0119] Preferably, 98 to 100% by weight, more preferably 99 to 100% by weight, still more preferably 99.5 to 100% by weight, and still more preferably 99.9 to 100% by weight of the first coat of the AMOx coating of the third catalyst consists of a zeolite material containing one or more of a platinum group metal, Fe, and Cu supported on a porous oxide material, more preferably a non-zeolite oxide material as defined above. More preferably, the first coat of the AMOx coating of the third catalyst consists of a zeolite material containing one or more of a platinum group metal, Fe, and Cu supported on a porous oxide material, more preferably a non-zeolite oxide material as defined above.

[0120] Preferably, the AMOx coating of the third catalyst consists of a first coat and a second coat.

[0121] Preferably, the third catalyst consists of a substrate, an SCR coating, and an AMOx coating.

[0122] -The third catalyst: SCR / PGM layered catalyst Preferably, the third catalyst contains an oxidation catalyst coating in addition to the SCR coating.

[0123] a) SCR coating Preferably, the SCR coating of the third catalyst is as defined above.

[0124] Preferably, the SCR coating of the third catalyst contains a zeolite material, more preferably consists of a zeolite material, the zeolite material more preferably has a framework type BEA, and contains iron and a non-zeolite oxide material.

[0125] Preferably, the SCR coating of the third catalyst further contains a non-zeolite oxide material, the non-zeolite oxide material more preferably contains one or more of zirconia, alumina, ceria, titania, silica, and mixed oxides containing two or more of Zr, Al, Ce, Ti, and Si, more preferably contains one or more of zirconia, alumina, ceria, and silica, and more preferably contains zirconia.

[0126] Preferably, the SCR coating of the third catalyst contains a non-zeolite material in an amount in the range of 0.5 to 12% by weight, more preferably in the range of 1 to 10% by weight, more preferably in the range of 1 to 6% by weight, and more preferably in the range of 2 to 5% by weight.

[0127] The proportion of the components of the SCR coating is preferably the same as that defined above for the third catalyst.

[0128] b) Oxidation catalyst coating Preferably, the oxidation catalyst coating of the third catalyst contains a platinum group metal, more preferably one or more of Pt, Pd, and Rh, more preferably one or more of Pt and Pd, and more preferably contains Pt.

[0129] Preferably, the oxidation catalyst coating of the third catalyst contains the platinum group metal in a supported amount in the range of 1 to 20 g / ft 3 in terms of elemental platinum group metal, more preferably in the range of 2 to 10 g / ft 3 and more preferably in the range of 3 to 5 g / ft 3 in terms of elemental platinum group metal.

[0130] Preferably, the oxidation catalyst coating of the third catalyst comprises a porous oxide material, more preferably a porous oxide material for supporting a platinum group metal, more preferably platinum, as defined above herein.

[0131] Preferably, the porous oxide material comprises oxygen and one or more of aluminum, titanium, cerium, silicon, and zirconium, preferably one or more of aluminum, titanium, and silicon, more preferably aluminum.

[0132] Preferably, the porous oxide material more preferably comprises oxygen and aluminum, and further comprises one or more of rare earth metals, more preferably one or more of lanthanum, yttrium, cerium, praseodymium, and neodymium, more preferably lanthanum.

[0133] Preferably, calculated as an oxide, 1 to 6% by weight, more preferably 2 to 5% by weight of the porous material consists of rare earth metals.

[0134] Preferably, 99 to 100% by weight, more preferably 99.5 to 100% by weight, more preferably 99.9 to 100% by weight of the porous material consists of oxygen, aluminum, and rare earth metals, preferably lanthanum.

[0135] Preferably, the oxidation catalyst coating of the third catalyst is in the range of 0.25 to 3 g / in 3 and more preferably in the range of 0.75 to 2 g / in 3 and contains an amount of the porous oxide material in the range.

[0136] Preferably, 98 to 100% by weight, more preferably 99 to 100% by weight, more preferably 99.5 to 100% by weight, more preferably 99.9 to 100% by weight of the oxidation catalyst coating of the third catalyst consists of the platinum group metal as defined above and the porous oxide material supporting the platinum group metal as defined above. More preferably, the oxidation catalyst coating of the third catalyst consists of the platinum group metal as defined above and the porous oxide material supporting the platinum group metal as defined above.

[0137] Preferably, the oxidation catalyst coating is disposed on the substrate of the third catalyst over 98 to 100%, preferably 99 to 100%, more preferably 99.5 to 100% of the axial length of the substrate, and the SCR coating is disposed on the oxidation catalyst coating over 98 to 100%, preferably 99 to 100%, more preferably 99.5 to 100% of the axial length of the substrate.

[0138] Preferably, at most 0.01% by weight, more preferably at most 0.001% by weight of the oxidation catalyst coating of the third catalyst consists of a zeolite material, and more preferably 0 to 0.0001% by weight of the oxidation catalyst coating of the third catalyst consists of a zeolite material.

[0139] In other words, preferably, the second coat of the AMOx coating of the third catalyst substantially does not contain a platinum group metal, and more preferably, does not contain a platinum group metal.

[0140] Preferably, the third catalyst comprises a substrate, an SCR coating, and an oxidation catalyst coating.

[0141] Preferably, no catalyst is present between the second catalyst according to (ii) and the third catalyst according to (iii).

[0142] The present invention further relates to a method for the simultaneous selective catalytic reduction of NOx, the oxidation of hydrocarbons, the oxidation of nitric oxide, and the oxidation of ammonia, the method comprising: (1) providing an exhaust gas stream from a gasoline engine containing one or more of NOx, ammonia, nitric oxide, and hydrocarbons; (2) passing the exhaust gas stream provided in (1) through an exhaust gas system according to the present invention.

Brief Description of the Drawings

[0143]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0144] The present invention is further illustrated by the following set of embodiments, as well as combinations of embodiments resulting from the dependencies and cross-references as shown. In particular, in each case where the scope of an embodiment is referred to, for example, in the context of a term such as "any one of Systems of Embodiments 1 to 4", all embodiments within this scope are meant to be explicitly disclosed to those skilled in the art, that is, it should be noted that this expression of the term is understood by those skilled in the art to be synonymous with "any one of Systems of Embodiments 1, 2, 3, and 4". Furthermore, it should be clearly noted that the following set of embodiments represents a properly structured part of the general description directed to the preferred aspects of the present invention, and thus appropriately supports, but does not represent, the claims of the present invention. 1. An exhaust gas treatment system for treating an exhaust gas stream exiting a gasoline engine, the exhaust gas treatment system having an upstream end for introducing the exhaust gas stream into the exhaust gas treatment system, the exhaust gas treatment system comprising (i) A three-way conversion catalyst, a first catalyst having an inlet end and an outlet end and including a coating disposed on a substrate, the coating including a platinum group metal component supported on a porous oxide material, the first catalyst (ii) A second catalyst which is a quaternary conversion catalyst, has an inlet end and an outlet end, and includes a coating disposed on a wall flow filter substrate, wherein the coating includes a platinum group metal component supported on a porous oxide material; and the second catalyst, (iii) A third catalyst having an inlet end and an outlet end, the third catalyst including a substrate and a coating for selective catalytic reduction of NOx, the SCR coating including a zeolite material containing one or more of Fe and Cu, and up to 0.0001 wt% of the SCR coating consisting of a platinum group metal; and the third catalyst, (i) The first catalyst according to (i) is the first catalyst of the exhaust gas treatment system downstream of the upstream end of the exhaust gas treatment system, and the inlet end of the first catalyst is disposed upstream of the outlet end of the first catalyst. In the exhaust gas treatment system, the second catalyst according to (ii) is positioned downstream of the first catalyst according to (i), and the inlet end of the second catalyst is disposed upstream of the outlet end of the second catalyst. In the exhaust gas treatment system, the third catalyst according to (iii) is positioned downstream of the second catalyst according to (ii), and the inlet end of the third catalyst is disposed upstream of the outlet end of the third catalyst. The exhaust gas treatment system. 2. The outlet end of the first catalyst according to (i) is in fluid communication with the inlet end of the second catalyst according to (ii), and there is no catalyst for treating the exhaust gas flow exiting the first catalyst positioned within the exhaust gas treatment system between the outlet end of the first catalyst according to (i) and the inlet end of the second catalyst according to (ii). The exhaust gas treatment system according to Embodiment 1. 3. The outlet end of the second catalyst according to (ii) is in fluid communication with the inlet end of the third catalyst according to (iii), and there is no catalyst for treating the exhaust gas flow exiting the second catalyst positioned within the exhaust gas treatment system between the outlet end of the second catalyst according to (ii) and the inlet end of the third catalyst according to (iii). The exhaust gas treatment system according to Embodiment 1 or 2. 4. The platinum group metal component of the coating of the first catalyst contains one or more of Pd, Rh, and Pt, preferably one or more of Pd and Rh, more preferably contains Pd and Rh, and is the exhaust gas treatment system according to any one of Embodiments 1 to 3. 5. The coating of the first catalyst contains the platinum group metal component in a range of 1 to 200 g / ft calculated as elemental platinum group metal, preferably in a range of 20 to 180 g / ft 3 and more preferably in a range of 50 to 150 g / ft 3 and is the exhaust gas treatment system according to any one of Embodiments 1 to 4. 3 8. The porous oxide material supporting the platinum group metal component of the coating of the first catalyst is selected from the group consisting of alumina, ceria, silica, zirconia, titania, mixtures of two or more thereof, and mixed oxides of two or more thereof, preferably selected from the group consisting of alumina, titania, zirconia, mixtures of two or more thereof, and mixed oxides of two or more thereof, more preferably selected from the group consisting of alumina, zirconia, mixtures of these two, and mixed oxides of these two, and more preferably is alumina, and is the exhaust gas treatment system according to any one of Embodiments 1 to 5. 6. The coating of the first catalyst further contains an oxygen storage component, and the oxygen storage component preferably contains cerium, more preferably contains one or more of cerium oxide, a mixture of oxides containing cerium, and a mixed oxide containing cerium. The mixed oxide containing cerium more preferably contains one or more of zirconium, yttrium, neodymium, lanthanum, hafnium, samarium, and praseodymium, more preferably contains one or more of zirconium, yttrium, neodymium, lanthanum, and praseodymium, and more preferably further contains zirconium, and is the exhaust gas treatment system according to any one of Embodiments 1 to 6. 7. The oxygen storage component of the coating of the first catalyst contains a mixed oxide containing cerium and zirconium, and is the exhaust gas treatment system according to any one of Embodiments 1 to 6. Preferably, 95 to 100% by weight, more preferably 98 to 100% by weight, still more preferably 99 to 100% by weight, and even more preferably 99.5 to 100% by weight of the oxygen storage component consists of a mixed oxide containing cerium and zirconium, More preferably, 10 to 60% by weight, still more preferably 20 to 60% by weight, and even more preferably 20 to 50% by weight of the oxygen storage component consists of cerium calculated as CeO2, and more preferably 20 to 90% by weight, still more preferably 40 to 70% by weight, and even more preferably 50 to 70% by weight of the oxygen storage component consists of zirconium calculated as ZrO2. More preferably, 0 to 20% by weight, still more preferably 0 to 10% by weight of the OSC consists of lanthanum and yttrium calculated as La2O3 and Y2O3. The exhaust gas treatment system according to Embodiment 7. 9. The coating of the first catalyst contains the oxygen storage component in an amount in the range of 0.3 to 5 g / in 3 Preferably in the range of 0.4 to 3.5 g / in 3 More preferably in the range of 0.45 to 3.0 g / in 3 More preferably in the range of 0.5 to 2.5 g / in 3 The exhaust gas treatment system according to Embodiment 7 or 8, containing the oxygen storage component in a supported amount in the range of. 10. In the coating of the first catalyst, the weight ratio of the porous oxide material to the oxygen storage component defined in any one of Embodiments 7 to 9 is in the range of 1:1 to 10:1, preferably in the range of 1:1 to 5:1. The exhaust gas treatment system according to any one of Embodiments 1 to 9. 11. The coating of the first catalyst further contains a non-zeolite oxide material, and the non-zeolite oxide material preferably contains one or more of zirconia, alumina, ceria, titania, silica, and mixed oxides containing two or more of Zr, Al, Ce, Ti, and Si. More preferably, it contains one or more of silica, ceria, alumina, and zirconia, and more preferably contains zirconia. The exhaust gas treatment system according to any one of Embodiments 1 to 10. 12. The coating of the first catalyst contains a non-zeolite oxide material in an amount in the range of 0.5 to 12% by weight, preferably in the range of 1 to 10% by weight, more preferably in the range of 1 to 5% by weight, calculated as an oxide, based on the weight of the coating of the first catalyst, for the exhaust gas treatment system according to Embodiment 11. 13. The coating of the first catalyst further contains an alkaline earth metal oxide, and the alkaline earth metal is preferably selected from the group consisting of barium, strontium, and magnesium, more preferably selected from the group consisting of barium and strontium, and even more preferably barium, for the exhaust gas treatment system according to any one of Embodiments 1 to 12. 14. The coating of the first catalyst contains an alkaline earth metal oxide in an amount in the range of 0.5 to 15% by weight, preferably in the range of 1 to 10% by weight, more preferably in the range of 1 to 6% by weight, based on the weight of the coating of the first catalyst, for the exhaust gas treatment system according to Embodiment 13. 15. 98 to 100% by weight, preferably 99 to 100% by weight, more preferably 99.5 to 100% by weight, even more preferably 99.9 to 100% by weight of the coating of the first catalyst consists of a platinum group metal component supported on a porous oxide material, preferably an oxygen storage component defined in any one of Embodiments 7 to 9, more preferably a non-zeolite oxide material defined in Embodiment 11 or 12, and even more preferably an alkaline earth metal oxide defined in Embodiment 13 or 14, for the exhaust gas treatment system according to any one of Embodiments 1 to 14. 16. The substrate of the first catalyst is a flow-through substrate, preferably a ceramic flow-through substrate, for the exhaust gas treatment system according to any one of Embodiments 1 to 15. 17. The first catalyst consists of a substrate and a coating, for the exhaust gas treatment system according to any one of Embodiments 1 to 16. 18. The platinum group metal component of the coating of the second catalyst contains one or more of Pd, Rh, and Pt, preferably one or more of Pd and Rh, more preferably contains Pd and Rh, Preferably, the coating of the second catalyst contains a platinum group metal component in the range of 1 to 100 g / ft calculated as elemental platinum group metal, more preferably in the range of 3 to 80 g / ft, 3 more preferably in the range of 4 to 50 g / ft, 3 more preferably in the range of 4 to 50 g / ft, 3 and the exhaust gas treatment system according to any one of Embodiments 1 to 17 includes the platinum group metal component in a supported amount within the range. 19. The porous oxide material supporting the platinum group metal component of the coating of the second catalyst is selected from the group consisting of alumina, ceria, silica, zirconia, titania, mixtures of two or more thereof, and mixed oxides of two or more thereof, preferably selected from the group consisting of alumina, titania, zirconia, mixtures of two or more thereof, and mixed oxides of two or more thereof, more preferably selected from the group consisting of alumina, zirconia, mixtures of these two, and mixed oxides of these two, and more preferably alumina. The exhaust gas treatment system according to any one of Embodiments 1 to 18. 20. The coating of the second catalyst further includes an oxygen storage component (OSC). The oxygen storage component preferably contains cerium, more preferably contains one or more of cerium oxide, mixtures of oxides containing cerium, and mixed oxides containing cerium. The mixed oxide containing cerium more preferably contains one or more of zirconium, yttrium, neodymium, lanthanum, hafnium, samarium, and praseodymium, more preferably contains one or more of zirconium, yttrium, neodymium, lanthanum, and praseodymium, and more preferably further contains zirconium. Preferably, the oxygen storage component of the coating of the second catalyst contains a mixed oxide containing cerium and zirconium. More preferably, 95 to 100% by weight, more preferably 98 to 100% by weight, more preferably 99 to 100% by weight, more preferably 99.5 to 100% by weight of the oxygen storage component consists of a mixed oxide containing cerium and zirconium. More preferably, 10 to 60% by weight, more preferably 20 to 60% by weight, and still more preferably 20 to 50% by weight of the oxygen storage component consists of cerium calculated as CeO2. More preferably, 20 to 90% by weight, more preferably 40 to 70% by weight, and still more preferably 50 to 70% by weight of the oxygen storage component consists of zirconium calculated as ZrO2. More preferably, 0 to 20% by weight, more preferably 0 to 10% by weight of the OSC consists of lanthanum and yttrium calculated as La2O3 and Y2O3. The exhaust gas treatment system according to any one of Embodiments 1 to 19. 21. The coating of the second catalyst contains an oxygen storage component in the range of 1.5 to 2.5 g / in 3 Preferably in the range of 1.2 to 2.2 g / in 3 More preferably in the range of 1.0 to 2.0 g / in 3 More preferably in the range of 1 to 1.75 g / in 3 The exhaust gas treatment system according to Embodiment 19 or 20, contained in a loading amount in the range. 22. In the coating of the second catalyst, the weight ratio of the porous oxide material to the oxygen storage component defined in any one of Embodiments 17 to 19 is in the range of 1:1 to 0.5:1, preferably in the range of 1:1 to 0.25:1. The exhaust gas treatment system according to any one of Embodiments 1 to 21. 23. The coating of the second catalyst further contains a non-zeolite oxide material. The non-zeolite oxide material preferably contains one or more of zirconia, alumina, ceria, titania, silica, and mixed oxides containing two or more of Zr, Al, Ce, Ti, and Si. More preferably, it contains one or more of silica, ceria, alumina, and zirconia. More preferably, it contains zirconia. Preferably, the coating of the second catalyst contains the non-zeolite oxide material in an amount in the range of 0.5 to 12% by weight, more preferably in the range of 1 to 10% by weight, and still more preferably in the range of 1 to 5% by weight, calculated as an oxide, based on the weight of the coating of the first catalyst. The exhaust gas treatment system according to any one of Embodiments 1 to 22. 24. The coating of the second catalyst further contains an alkaline earth metal oxide, and the alkaline earth metal is preferably selected from the group consisting of barium, strontium, and magnesium, more preferably selected from the group consisting of barium and strontium, and even more preferably barium. The coating of the second catalyst contains an alkaline earth metal oxide preferably in an amount in the range of 0.5 to 15% by weight, preferably in the range of 1 to 10% by weight, more preferably in the range of 1 to 6% by weight, based on the weight of the coating of the first catalyst, for the exhaust gas treatment system according to any one of Embodiments 1 to 23. 98 to 100% by weight, preferably 99 to 100% by weight, more preferably 99.5 to 100% by weight, even more preferably 99.9 to 100% by weight of the coating of the second catalyst consists of a platinum group metal component supported on a porous oxide material, preferably an oxygen storage component defined by any one of Embodiments 20 to 22, more preferably a non-zeolite oxide material defined by Embodiment 23, and even more preferably an alkaline earth metal oxide defined by Embodiment 24, for the exhaust gas treatment system according to any one of Embodiments 1 to 24. 26. The substrate of the second catalyst is a ceramic wall flow filter substrate, for the exhaust gas treatment system according to any one of Embodiments 1 to 25. 27. The second catalyst consists of a substrate and a coating, for the exhaust gas treatment system according to any one of Embodiments 1 to 26. 28. The zeolite material contained in the SCR coating of the third catalyst is a 12-ring pore zeolite material, and the 12-ring pore zeolite material preferably has a framework type selected from the group consisting of BEA, MOR, FAU, GME, OFF, mixtures of two or more thereof, and mixed types of two or more thereof, more preferably a framework type selected from the group consisting of BEA, MOR, FAU, mixtures of two or more thereof, and mixed types of two or more thereof, and even more preferably a framework type selected from the group consisting of BEA and FAU. Even more preferably, the 12-ring pore zeolite material contained in the SCR coating of the third catalyst has a framework type of BEA. Preferably, the zeolite material contained in the SCR coating of the third catalyst is an exhaust gas treatment system according to any one of Embodiments 1 to 27, which contains Fe. 29. 95 to 100% by weight, preferably 98 to 100% by weight, more preferably 99 to 100% by weight, and still more preferably 99.5 to 100% by weight of the framework structure of the 12-membered ring pore zeolite material contained in the SCR coating of the third catalyst consists of Si, Al, and O. In the framework structure, the molar ratio of Si to Al calculated as molar SiO2:Al2O3 is more preferably in the range of 2:1 to 40:1, more preferably in the range of 3:1 to 30:1, more preferably in the range of 4:1 to 20:1, and still more preferably in the range of 6:1 to 15:1. An exhaust gas treatment system according to any one of Embodiments 1 to 28. 30. The zeolite material contained in the SCR coating of the third catalyst contains iron, and the amount of iron contained in the zeolite material, calculated as Fe2O3, is preferably in the range of 0.1 to 10.0% by weight, more preferably in the range of 0.5 to 8% by weight, and still more preferably in the range of 1.5 to 7.5% by weight based on the total weight of the zeolite material. An exhaust gas treatment system according to any one of Embodiments 1 to 29. 31. The SCR coating of the third catalyst further contains a non-zeolite oxide material, and the non-zeolite oxide material preferably contains one or more of zirconia, alumina, ceria, titania, silica, and mixed oxides containing two or more of Zr, Al, Ce, Ti, and Si, and more preferably contains one or more of zirconia, alumina, ceria, and silica. An exhaust gas treatment system according to any one of Embodiments 1 to 26. 32. The SCR coating of the third catalyst contains a non-zeolite oxide material in an amount in the range of 0.5 to 12% by weight, preferably in the range of 1 to 10% by weight, and more preferably in the range of 1 to 6% by weight, calculated as an oxide, based on the weight of the SCR coating of the third catalyst. An exhaust gas treatment system according to Embodiment 31. 33. The maximum of 0.00001% by weight of the SCR coating of the third catalyst consists of a platinum group metal. Preferably, 0 to 0.00001% by weight of the SCR coating of the third catalyst consists of a platinum group metal. The exhaust gas treatment system according to any one of Embodiments 1 to 32. 34. The substrate of the third catalyst is a flow-through substrate, preferably a ceramic flow-through substrate. The exhaust gas treatment system according to any one of Embodiments 1 to 33. 35. 98 to 100% by weight, preferably 99 to 100% by weight, more preferably 99.5 to 100% by weight, still more preferably 99.9 to 100% by weight of the SCR coating of the third catalyst consists of a zeolite material containing one or more of Fe and Cu, preferably a non-zeolite oxide material defined in Embodiment 31 or 32. The exhaust gas treatment system according to any one of Embodiments 1 to 34. 36. The third catalyst consists of a substrate and an SCR coating. The exhaust gas treatment system according to any one of Embodiments 1 to 35. 37. The SCR coating contains a zeolite material, preferably consists of a zeolite material. The zeolite material preferably has a framework type BEA and contains iron and a non-zeolite oxide material, preferably zirconia. The exhaust gas treatment system according to Embodiment 36. 38. The third catalyst includes an ammonia oxidation catalyst (AMOx) coating in addition to the SCR coating. The exhaust gas treatment system according to any one of Embodiments 1 to 37. 39. The SCR coating of the third catalyst contains a zeolite material, preferably consists of a zeolite material. The zeolite material preferably has a framework type BEA and contains iron and a non-zeolite oxide material, preferably ceria. The exhaust gas treatment system according to Embodiment 38. 40. The AMOx coating of the third catalyst contains a platinum group metal, preferably one or more of Pt, Pd, and Rh, more preferably one or more of Pt and Pd, still more preferably Pt. The exhaust gas treatment system according to Embodiment 38 or 39. 41. The AMOx coating of the third catalyst contains a platinum group metal, calculated as elemental platinum group metal, at 1 to 20 g / ft3 in the range of, preferably 2 to 10 g / ft 3 in the range of, more preferably 3 to 5 g / ft 3 The exhaust gas treatment system according to Embodiment 40, containing the loading amount in the range of 42. The AMOx coating of the third catalyst preferably contains a porous oxide material for supporting a platinum group metal defined in Embodiment 40 or 41. The porous oxide material is selected from the group consisting of titania, alumina, ceria, silica, zirconia, mixtures of two or more thereof, and mixed oxides of two or more thereof, preferably selected from the group consisting of titania, alumina, and silica, and more preferably titania. The exhaust gas treatment system according to any one of Embodiments 38 to 41. 43. The AMOx coating of the third catalyst contains a porous oxide material in the range of 0.25 to 3 g / in 3 in the range of, preferably 0.5 to 1.5 g / in 3 The exhaust gas treatment system according to Embodiment 42, containing the porous oxide material in the amount in the range of 44. The AMOx coating of the third catalyst contains a zeolite material containing one or more of (further) Fe and Cu, preferably a zeolite material containing Fe. The exhaust gas treatment system according to any one of Embodiments 38 to 43. 45. The zeolite material of the AMOx coating of the third catalyst is a 12-ring pore zeolite material. The 12-ring pore zeolite material is preferably selected from the group consisting of BEA, MOR, FAU, GME, OFF, mixtures of two or more thereof, and mixed types of two or more thereof. More preferably, it is selected from the group consisting of BEA, MOR, FAU, mixtures of two or more thereof, and mixed types of two or more thereof. More preferably, it has a framework type selected from the group consisting of BEA and FAU. More preferably, the 12-ring pore zeolite material contained in the AMOx coating of the third catalyst has a framework type of BEA. The exhaust gas treatment system according to Embodiment 44. 46. The 95 to 100 wt%, preferably 98 to 100 wt%, more preferably 99 to 100 wt%, still more preferably 99.5 to 100 wt% of the framework structure of the 12-membered ring porous zeolite material contained in the AMOx coating of the third catalyst consists of Si, Al, and O. In the framework structure, the molar ratio of Si to Al calculated as molar SiO2:Al2O3 is more preferably in the range of 2:1 to 40:1, more preferably in the range of 3:1 to 30:1, more preferably in the range of 4:1 to 20:1, still more preferably in the range of 6:1 to 15:1. The exhaust gas treatment system according to Embodiment 45. 47. The zeolite material contained in the AMOx coating of the third catalyst contains iron, and the amount of iron contained in the zeolite material, calculated as Fe2O3, is in the range of 0.1 to 15.0 wt%, more preferably in the range of 0.5 to 10.0 wt%, still more preferably in the range of 1.5 to 7.5 wt% based on the total weight of the zeolite material. The exhaust gas treatment system according to any one of Embodiments 44 to 46. 48. In the AMOx coating, the weight ratio of the zeolite material containing one or more of Fe and Cu to the porous oxide material defined in Embodiment 42 or 43 is in the range of 0.5:1 to 2:1, preferably in the range of 0.75:1 to 1.5:1, more preferably in the range of 1:1 to 1.25:1. The exhaust gas treatment system according to any one of Embodiments 44 to 47. 49. The AMOx coating further contains a non-zeolite oxide material, and the non-zeolite oxide material preferably contains one or more of zirconia, alumina, ceria, titania, silica, and mixed oxides containing two or more of Zr, Al, Ce, Ti, and Si, more preferably contains one or more of zirconia, alumina, ceria, and silica, still more preferably contains silica. The exhaust gas treatment system according to any one of Embodiments 38 to 48. 50. The AMOx coating of the third catalyst contains the non-zeolite oxide material in an amount in the range of 0.5 to 18 wt%, more preferably in the range of 5 to 16 wt%, still more preferably in the range of 8 to 13 wt%, calculated as an oxide, based on the weight of the coating of the third catalyst. The exhaust gas treatment system according to Embodiment 49. 51. 98 to 100 wt%, preferably 99 to 100 wt%, more preferably 99.5 to 100 wt%, and even more preferably 99.9 to 100 wt% of the AMOx coating of the third catalyst consists of a platinum group metal as defined in Embodiment 40 or 41, a porous oxide material supporting a platinum group metal as defined in Embodiment 42 or 43, a zeolite material containing one or more of Fe and Cu as defined in any one of Embodiments 44 to 48, and preferably a non-zeolite oxide material as defined in Embodiment 49 or 50. The exhaust gas treatment system according to any one of Embodiments 38 to 50. 52. The AMOx coating is disposed on the substrate of the third catalyst over 98 to 100%, preferably 99 to 100%, more preferably 99.5 to 100% of the axial length of the substrate. The SCR coating is disposed on the AMOx coating over 98 to 100%, preferably 99 to 100%, more preferably 99.5 to 100% of the axial length of the substrate. The exhaust gas treatment system according to any one of Embodiments 38 to 50. 53. The third catalyst includes an inlet zone containing, preferably consisting of, an SCR coating, and an outlet zone containing, preferably consisting of, an ammonia oxidation catalyst coating. The exhaust gas treatment system according to any one of Embodiments 1 to 35. 54. The inlet zone extends over x% of the axial length of the substrate from the inlet end to the outlet end of the substrate, where x ranges from 20 to 60, preferably from 30 to 55, more preferably from 45 to 55. The exhaust gas treatment system according to Embodiment 53. 55. The outlet zone extends over y% (y = 100 - x) of the axial length of the substrate from the outlet end to the inlet end of the substrate. The exhaust gas treatment system according to Embodiment 54. 56. The SCR coating of the inlet zone contains, preferably consists of, a zeolite material. The zeolite material preferably has a framework type BEA and contains iron and a non-zeolite oxide material, preferably silica and alumina. The exhaust gas treatment system according to any one of Embodiments 53 to 55. 57. The AMOx coating in the outlet zone is - a first coat comprising a platinum group metal supported on a porous oxide material and a zeolite material containing at least one of Fe and Cu; - a second coat comprising a zeolite material containing at least one of Fe and Cu, wherein a maximum of 0.0001% by weight of the first coat consists of a platinum group metal. The exhaust gas treatment system according to any one of Embodiments 53 to 56, wherein the first coat is disposed on the substrate over the length of the outlet zone, the second coat is disposed on the first coat over the length of the outlet zone, or the second coat is disposed on the substrate over the length of the outlet zone and the first coat is disposed on the second coat over the length of the outlet zone. 58. The zeolite material of the second coat of the AMOx coating of the third catalyst is a 12-membered ring pore zeolite material, and the 12-membered ring pore zeolite material is preferably selected from the group consisting of BEA, MOR, FAU, GME, OFF, mixtures of two or more thereof, and mixed types of two or more thereof, more preferably selected from the group consisting of BEA, MOR, FAU, mixtures of two or more thereof, and mixed types of two or more thereof, and even more preferably has a framework type selected from the group consisting of BEA and FAU. Even more preferably, the 12-membered ring pore zeolite material contained in the AMOx coating of the third catalyst has a framework type of BEA. The exhaust gas treatment system according to Embodiment 57. 59. 95 to 100% by weight, preferably 98 to 100% by weight, more preferably 99 to 100% by weight, and even more preferably 99.5 to 100% by weight of the framework structure of the 12-membered ring pore zeolite material contained in the second coat of the AMOx coating of the third catalyst consists of Si, Al, and O. In the framework structure, the molar ratio of Si to Al calculated as molar SiO2:Al2O3 is more preferably in the range of 2:1 to 40:1, more preferably in the range of 3:1 to 30:1, more preferably in the range of 4:1 to 20:1, and even more preferably in the range of 6:1 to 15:1. The exhaust gas treatment system according to Embodiment 58. 60. The zeolite material contained in the second coat of the AMOx coating of the third catalyst contains iron, and the amount of iron contained in the zeolite material, calculated as Fe2O3, is in the range of 0.1 to 15.0% by weight, more preferably in the range of 1.0 to 10.0% by weight, more preferably in the range of 3.0 to 7.5% by weight, based on the total weight of the zeolite material. The exhaust gas treatment system according to any one of Embodiments 57 to 59. 61. Up to 0.00001% by weight of the second coat of the AMOx coating of the third catalyst consists of a platinum metal component, preferably 0 to 0.00001% by weight of the second coat of the AMOx coating of the third catalyst consists of a platinum group metal component. The exhaust gas treatment system according to any one of Embodiments 57 to 60. 62. The second coat of the AMOx coating of the third catalyst further contains a non-zeolite oxide material, and the non-zeolite oxide material preferably contains one or more of zirconia, alumina, ceria, titania, silica, and mixed oxides containing two or more of Zr, Al, Ce, Ti, and Si, more preferably contains one or more of zirconia, alumina, ceria, and silica, more preferably contains ceria. The exhaust gas treatment system according to any one of Embodiments 57 to 61. 63. The second coat of the AMOx coating of the third catalyst contains the non-zeolite oxide material in an amount in the range of 0.5 to 12% by weight, more preferably in the range of 1 to 10% by weight, more preferably in the range of 1 to 6% by weight, more preferably in the range of 1 to 4% by weight, calculated as the oxide, based on the weight of the second coat of the AMOx coating of the third catalyst. The exhaust gas treatment system according to Embodiment 62. 64. 98 to 100% by weight, preferably 99 to 100% by weight, more preferably 99.5 to 100% by weight, more preferably 99.9 to 100% by weight of the second coat of the AMOx coating of the third catalyst consists of a zeolite material containing one or more of Fe and Cu, preferably a non-zeolite oxide material defined in Embodiment 62 or 63. The exhaust gas treatment system according to any one of Embodiments 57 to 63. 65. The platinum group metal contained in the first coat of the AMOx coating of the third catalyst is one or more of Pt, Pd, and Rh, more preferably one or more of Pt and Pd, and still more preferably Pt, in the exhaust gas treatment system according to any one of Embodiments 57 to 64. 66. The first coat of the AMOx coating of the third catalyst contains the platinum group metal in a range of 1 to 20 g / ft 3 calculated as elemental platinum group metal, preferably in a range of 2 to 10 g / ft 3 and more preferably in a range of 3 to 7.5 g / ft 3 in the exhaust gas treatment system according to Embodiment 65. 67. The porous oxide material of the first coat of the AMOx coating of the third catalyst is selected from the group consisting of titania, alumina, ceria, silica, zirconia, mixtures of two or more thereof, and mixed oxides of two or more thereof, preferably selected from the group consisting of titania, silica, and alumina, and still more preferably titania, in the exhaust gas treatment system according to any one of Embodiments 57 to 66. 68. The first coat of the AMOx coating of the third catalyst contains the porous oxide material in an amount in the range of 10 to 80% by weight, preferably in the range of 30 to 70% by weight, and more preferably in the range of 45 to 55% by weight, based on the weight of the first coat of the AMOx coating of the third catalyst, in the exhaust gas treatment system according to any one of Embodiments 57 to 67. 69. The zeolite material of the first coat of the AMOx coating of the third catalyst is a 12-membered ring pore zeolite material, and the 12-membered ring pore zeolite material is preferably selected from the group consisting of BEA, MOR, FAU, GME, OFF, mixtures of two or more of them, and mixed types of two or more of them, more preferably selected from the group consisting of BEA, MOR, FAU, mixtures of two or more of them, and mixed types of two or more of them, more preferably having a framework type selected from the group consisting of BEA and FAU. More preferably, the 12-membered ring pore zeolite material contained in the second coat of the AMOx coating of the third catalyst has a framework type BEA. The exhaust gas treatment system according to any one of Embodiments 57 to 68. 70. 95 to 100% by weight, preferably 98 to 100% by weight, more preferably 99 to 100% by weight, more preferably 99.5 to 100% by weight of the framework structure of the 12-membered ring pore zeolite material contained in the first coat of the AMOx coating of the third catalyst consists of Si, Al, and O. In the framework structure, the molar ratio of Si to Al calculated as molar SiO2:Al2O3 is more preferably in the range of 2:1 to 40:1, more preferably in the range of 3:1 to 30:1, more preferably in the range of 4:1 to 20:1, more preferably in the range of 6:1 to 15:1. The exhaust gas treatment system according to Embodiment 69. 71. The zeolite material contained in the first coat of the AMOx coating of the third catalyst contains iron, and the amount of iron contained in the zeolite material, calculated as Fe2O3, is preferably in the range of 1.0 to 15.0% by weight, more preferably in the range of 2.0 to 10.0% by weight, more preferably in the range of 3.0 to 7.5% by weight based on the total weight of the zeolite material. The exhaust gas treatment system according to any one of Embodiments 57 to 70. 72. In the first coat of the AMOx coating of the third catalyst, the weight ratio of the zeolite material containing one or more of Fe and Cu to the porous oxide material is in the range of 0.25:1 to 2:1, preferably in the range of 0.5:1 to 1:1. The exhaust gas treatment system according to any one of Embodiments 57 to 71. 73. The first coat of the AMOx coating of the third catalyst further comprises a non-zeolite oxide material, which preferably comprises one or more of zirconia, alumina, ceria, titania, silica, and mixed oxides containing two or more of Zr, Al, Ce, Ti, and Si, more preferably one or more of zirconia, alumina, ceria, and titania, and more preferably silica, and is an exhaust gas treatment system according to any one of Embodiments 57 to 72. 74. The first coat of the AMOx coating of the third catalyst contains the non-zeolite oxide material in an amount in the range of 0.5 to 18% by weight, more preferably in the range of 5 to 16% by weight, and more preferably in the range of 8 to 13% by weight, calculated as an oxide, based on the weight of the first coat of the AMOx coating of the third catalyst, and is an exhaust gas treatment system according to Embodiment 73. 75. 98 to 100% by weight, preferably 99 to 100% by weight, more preferably 99.5 to 100% by weight, and more preferably 99.9 to 100% by weight of the first coat of the AMOx coating of the third catalyst consists of a zeolite material containing one or more of a platinum group metal, Fe, and Cu supported on a porous oxide material, and preferably a non-zeolite oxide material defined in Embodiment 73 or 74, and is an exhaust gas treatment system according to any one of Embodiments 57 to 74. 76. The AMOx coating of the third catalyst consists of a first coat and a second coat, and is an exhaust gas treatment system according to any one of Embodiments 57 to 75. 77. The third catalyst consists of a substrate, an SCR coating, and an AMOx coating, and is an exhaust gas treatment system according to any one of Embodiments 57 to 76. 78. The third catalyst includes an oxidation catalyst coating in addition to the SCR coating, and is an exhaust gas treatment system according to any one of Embodiments 1 to 37. 79. The oxidation catalyst coating of the third catalyst contains a platinum group metal, preferably one or more of Pt, Pd, and Rh, more preferably one or more of Pt and Pd, and more preferably Pt, and is an exhaust gas treatment system according to Embodiment 78. 80. The oxidation catalyst coating of the third catalyst contains a platinum group metal in the range of 1 to 20 g / ft, calculated as the elemental platinum group metal, preferably in the range of 2 to 10 g / ft, more preferably in the range of 3 to 5 g / ft, of the exhaust gas treatment system according to Embodiment 79. 3 81. The oxidation catalyst coating of the third catalyst preferably contains a porous oxide material for supporting a platinum group metal defined in Embodiment 79 or 80, more preferably platinum, of the exhaust gas treatment system according to any one of Embodiments 78 to 80. 3 82. The porous oxide material contains oxygen and one or more of aluminum, titanium, cerium, silicon, and zirconium, preferably contains one or more of aluminum, titanium, and silicon, more preferably contains aluminum, of the exhaust gas treatment system according to Embodiment 81. 3 83. The porous oxide material preferably contains oxygen and aluminum, and further contains one or more of rare earth metals, more preferably one or more of lanthanum, yttrium, cerium, praseodymium, and neodymium, more preferably lanthanum, of the exhaust gas treatment system according to Embodiment 81 or 82. 84. Calculated as an oxide, 1 to 6% by weight, preferably 2 to 5% by weight, of the porous material consists of rare earth metals, of the exhaust gas treatment system according to any one of Embodiments 81 to 83. 85. 99 to 100% by weight, preferably 99.5 to 100% by weight, more preferably 99.9 to 100% by weight, of the porous material consists of oxygen, aluminum, and rare earth metals, preferably consists of lanthanum, of the exhaust gas treatment system according to any one of Embodiments 81 to 84. 86. The oxidation catalyst coating of the third catalyst contains a porous oxide material in the range of 0.25 to 3 g / in, preferably in the range of 0.75 to 2 g / in, of the exhaust gas treatment system according to any one of Embodiments 81 to 85. 87. The oxidation catalyst coating of the third catalyst preferably contains a porous oxide material for supporting a platinum group metal defined in Embodiment 79 or 80, more preferably platinum, of the exhaust gas treatment system according to any one of Embodiments 78 to 80. 88. The porous oxide material contains oxygen and one or more of aluminum, titanium, cerium, silicon, and zirconium, preferably contains one or more of aluminum, titanium, and silicon, more preferably contains aluminum, of the exhaust gas treatment system according to Embodiment 87. 89. The porous oxide material preferably contains oxygen and aluminum, and further contains one or more of rare earth metals, more preferably one or more of lanthanum, yttrium, cerium, praseodymium, and neodymium, more preferably lanthanum, of the exhaust gas treatment system according to Embodiment 87 or 88. 3 90. Calculated as an oxide, 1 to 6% by weight, preferably 2 to 5% by weight, of the porous material consists of rare earth metals, of the exhaust gas treatment system according to any one of Embodiments 87 to 89. 3 91. 99 to 100% by weight, preferably 99.5 to 100% by weight, more preferably 99.9 to 100% by weight, of the porous material consists of oxygen, aluminum, and rare earth metals, preferably consists of lanthanum, of the exhaust gas treatment system according to any one of Embodiments 87 to 90. 87. 98 to 100 wt%, preferably 99 to 100 wt%, more preferably 99.5 to 100 wt%, even more preferably 99.9 to 100 wt% of the oxidation catalyst coating of the third catalyst consists of a platinum group metal defined in Embodiment 79 or 80 and a porous oxide material supporting a platinum group metal defined in any one of Embodiments 81 to 86, and is an exhaust gas treatment system according to any one of Embodiments 78 to 86. 88. The oxidation catalyst coating is disposed on the substrate of the third catalyst over 98 to 100%, preferably 99 to 100%, more preferably 99.5 to 100% of the axial length of the substrate, and the SCR coating is disposed on the oxidation catalyst coating over 98 to 100%, preferably 99 to 100%, more preferably 99.5 to 100% of the axial length of the substrate, and is an exhaust gas treatment system according to any one of Embodiments 78 to 87. 89. The third catalyst consists of a substrate, an SCR coating, and an oxidation catalyst coating, and is an exhaust gas treatment system according to any one of Embodiments 78 to 88. 90. At most 0.01 wt%, more preferably at most 0.001 wt% of the oxidation catalyst coating of the third catalyst consists of a zeolite material, and more preferably 0 to 0.0001 wt% of the oxidation catalyst coating of the third catalyst consists of a zeolite material, and is an exhaust gas treatment system according to any one of Embodiments 78 to 89. 91. A method for the simultaneous selective catalytic reduction of NOx, oxidation of hydrocarbons, oxidation of nitric oxide, and oxidation of ammonia, comprising: (1) providing an exhaust gas stream from a gasoline engine containing one or more of NOx, ammonia, nitric oxide, and hydrocarbons; (2) passing the exhaust gas stream provided in (1) through the exhaust gas system according to any one of Embodiments 1 to 90.

[0145] In the context of the present invention, the term "disposed on a substrate" means that the coating is disposed on the surface of the inner wall of the substrate, and the term "surface of the inner wall" should be understood as the "naked" or "bare" or "blank" surface of the wall, i.e., the untreated surface of the wall consisting of the wall material, apart from any inevitable impurities that may contaminate the surface.

[0146] Furthermore, in the context of the present invention, the term "X is one or more of A, B, and C" (where X is a given feature and each of A, B, and C represents a specific realization of the feature) should be understood to disclose that X is either A, or B, or C, or A and B, or A and C, or B and C, or A, B, and C. In this regard, it should be noted that those skilled in the art can transfer the above abstract terms to specific examples. For example, if X is a chemical element and A, B, and C are specific elements such as Li, Na, and K, or if X is a temperature and A, B, and C are specific temperatures such as 10°C, 20°C, and 30°C. In this regard, it should be further noted that those skilled in the art can extend the above terms to a less specific recognition of the feature (e.g., "X is one or more of A and B" discloses that X is either A, or B, or A and B), or a more specific recognition of the feature (e.g., "X is one or more of A, B, C, and D" discloses that X is either A, or B, or C, or D, or A and B, or A and C, or A and D, or B and C, or B and D, or C and D, or A, B, and C, or A, B, and D, or B, C, and D, or A, B, C, and D).

[0147] Furthermore, in the context of the present invention, the term "consisting of" with respect to the weight % of one or more components indicates the amount of the weight % of the components based on 100% by weight of the entity in question. For example, the expression "0 to 0.001% by weight of the second coating consists of platinum" indicates that 0 to 0.001% by weight out of 100% by weight of the components constituting the coating is platinum.

[0148] Furthermore, in the context of the present invention, the term "close-coupled" catalyst is used herein to define a catalyst that is the first catalyst to receive the exhaust gas flow exiting the engine.

[0149] The present invention is further illustrated by the following examples.

Examples

[0150] Analysis - Measurement 1.1 Determination of the BET specific surface area of alumina The BET specific surface area of alumina was determined in accordance with DIN 66131 or DIN - ISO 9277 using liquid nitrogen.

[0151] 1.2 Determination of the volume - based particle size distribution (Dv90) The particle size distribution was determined by the static light scattering method using a Sympatec HELOS / BR - OM & QUIXEL wet dispersion device equipped with a laser (HeNe) diffraction sensor having a 31 - channel multi - element detection range covering 0.1 to 875 microns.

[0152] Reference Example 1 Three - way conversion (TWC) catalyst An aqueous mixture of palladium and rhodium salt precursors was impregnated onto high - porosity alumina and onto ceria - zirconia. The resulting mixtures of Pd / Rh on alumina (100% high - porosity alumina) and on ceria - zirconia (solids content: 60 to 75% by weight) were calcined at 400 to 600 °C for 2 to 4 hours.

[0153] A mixture was prepared by mixing water, n-octanol, and precursors of the barrier and zirconia. The amount of the barrier precursor was calculated such that the final loading of BaO in the catalyst after calcination was 1-10 wt% based on the weight of the coating, and the amount of the zirconia precursor was calculated such that the loading of ZrO2 from the source in the catalyst after calcination was 1-5 wt% based on the weight of the coating. The obtained calcined Pd / Rh on alumina and / or ceria-zirconia was added to a mixture containing n-octanol to obtain a slurry. The slurry solids were adjusted to 30-50 wt% to improve the pH and viscosity measurements and wet grinding. After grinding, nitric acid was added to adjust the pH of the slurry to pH 3-5. The particle size distribution (Dv90) of the ground slurry was 10-20 micrometers.

[0154] The resulting slurry was disposed over the entire length of an uncoated ceramic honeycomb flow-through substrate (diameter: 4.66 inches × length: 2.5 inches, 750 / (2.54) 2 cells / square centimeter and a cylindrical substrate having a wall thickness of 0.0635 millimeter (2.5 mils)), dried at 120-180 °C, and further calcined in air at 400-600 °C. The final coating contains highly porous alumina, ceria-zirconia, Pd, Rh, zirconia, and the barrier. The coating loading is 1.5-4 g / in 3 is.

[0155] Reference Example 2 Quaternary Conversion (FWC) Catalyst An aqueous mixture of palladium and rhodium salt precursors was impregnated onto highly porous alumina and ceria-zirconia. The resulting mixture of Pd / Rh on alumina and ceria-zirconia (solids: 50-80 wt%) was calcined at 400-600 °C for 2-4 hours.

[0156] A mixture was prepared by mixing water, n-octanol, and precursors of the barrier and zirconia. The amount of the barrier precursor was calculated such that the final loading of BaO in the catalyst after calcination was 1 to 5 wt% based on the weight of the coating, and the amount of the zirconia precursor was calculated such that the loading of ZrO2 from the source in the catalyst after calcination was 1 to 5 wt% based on the weight of the coating. The calcined Pd / Rh on the obtained alumina and / or ceria-zirconia was added to a mixture containing n-octanol to obtain a slurry. The slurry solids were adjusted to 30 to 50 wt% to improve the pH and viscosity measurements and wet grinding. After grinding, nitric acid was added to adjust the pH of the slurry to pH 3 to 5. The particle size distribution (Dv90) of the ground slurry was 7 to 18 micrometers.

[0157] The obtained slurry was disposed over the entire length of an uncoated ceramic honeycomb wall flow substrate (diameter: 4.66 inches × length: 4.26 inches, 300 / (2.54) 2 cells / square centimeter and a cylindrical substrate having a wall thickness of 0.2 millimeter (8 mils)), dried at 120 to 180 °C, and further calcined in air at 400 to 600 °C. The final coating contains highly porous alumina, ceria-zirconia, Pd, Rh, zirconia, and the barrier. The coating loading is 1 to 3 g / in 3 is.

[0158] Comparative Example 1 Exhaust gas treatment system not according to the present invention The exhaust gas treatment system of Comparative Example 1 includes the catalyst of Reference Example 1 (TWC catalyst) as Catalyst 1, the catalyst of Reference Example 2 (FWC catalyst) as Catalyst 2, and the catalyst of Reference Example 1 (TWC catalyst) as Catalyst 3. Catalyst 1 is positioned upstream of Catalyst 2, and Catalyst 2 is positioned upstream of Catalyst 3. There is no catalyst between Catalyst 1 and Catalyst 2 and between Catalyst 2 and Catalyst 3, and Catalyst 1 is a close-coupled catalyst. This system is shown in FIG. 1.

[0159] Reference Example 3 Ammonia oxidation (AMOx) catalyst PGM-containing bottom coating: An aqueous mixture of a Pt precursor was impregnated in an aqueous medium onto a high surface area and porous oxide support such as alumina, titania, ceria-zirconia or mixtures thereof. The resulting mixture had a solids content of 50-70%. This slurry was wet milled to obtain a Dv90 of 10-25 micrometers. Separately, an appropriate amount of Fe-BEA (Fe content calculated as Fe2O3: 1.5-7.5 wt% based on the weight of the zeolite, silica to alumina molar ratio 6-15:1) and silica (8-13 wt% calculated as SiO2 based on the weight of the PGM-containing coating) were mixed in distilled water to obtain a mixture having a solids content of 30-50%. The BEA-containing mixture and the Pt-containing mixture were mixed and wet milled to obtain a particle size distribution Dv90 of 2-15 micrometers. Then, the resulting slurry was disposed over the entire length of an uncoated ceramic honeycomb flow-through substrate (diameter: 5.66 inches × length: 3 inches, 400 / (2.54) 2 cpsi and a cylindrical substrate having a wall thickness of 0.1 millimeter (4 mils), dried at 120-180 °C, and calcined in air at 400-600 °C. The loading of the PGM coating was 1-3 g / in 3 was.

[0160] PGM-free top coating: A mixture of a ceria precursor (calculated as CeO2: 1-4 wt% based on the weight of the PGM-free coating) and distilled water was prepared, and Fe-BEA zeolite (Fe content calculated as Fe2O3: 1.5-7.5 wt% based on the weight of the zeolite, silica to alumina molar ratio 6-15:1) was added to the mixture under constant mixing. The solids content of the resulting slurry was 20-40%. The slurry was dispersed and mixed to obtain a Dv90 of 2-12 micrometers. Then, the resulting slurry was disposed over the entire length of a substrate coated with a PGM-containing bottom coating, dried at 120-180 °C, and calcined in air at 400-600 °C. The loading of the PGM-free coating was 1-3 g / in 3 was.

[0161] Reference Example 4 Selective Catalytic Reduction (SCR) / AMOx Catalyst SCR Coating: A mixture of distilled water and Fe-BEA zeolite (Fe content calculated as Fe2O3: 1.5 to 7.5 wt% based on the weight of the zeolite, silica to alumina molar ratio 6 to 15:1) was prepared, and silica and alumina powders were added as minor additives. The amount of the additives was calculated such that the amount of silica + alumina in the SCR coating would be 1 to 5 wt% based on the weight of the SCR coating, calculated as oxides (SiO2, Al2O3). The solids content of the resulting mixture was 30 to 50%. The slurry was wet-milled to obtain a Dv90 of 3 to 18 micrometers.

[0162] The resulting slurry was disposed over 50% of the total length of an uncoated ceramic honeycomb flow-through substrate from the inlet end of the substrate towards the outlet end of the substrate (diameter: 5.66 inches × length: 3 inches, 400 / (2.54) 2 cells / square centimeter and a cylindrical substrate having a wall thickness of 0.1 millimeter (4 mils)), dried at 120 to 180 °C, and further fired in air at 400 to 600 °C. The SCR coating contains Fe-BEA zeolite, alumina, and silica. The loading of the SCR coating was 2 to 4 g / in 3 was.

[0163] AMOx Coating: PGM-containing bottom coat: Prepared in the same manner as in Reference Example 3 PGM-free top coat: Prepared in the same manner as in Reference Example 3 The resulting slurry for the PGM bottom coat was disposed over 50% of the total length of a ceramic honeycomb flow-through substrate coated with the SCR coating from the outlet end of the substrate towards the inlet end of the substrate, and the resulting slurry for the PGM-free top coat was disposed over 50% of the total length of the ceramic honeycomb flow-through substrate coated on top of the PGM bottom coating. The loading of the AMOx coating was 2.5 to 4 g / in3 It was.

[0164] Reference Example 5 Selective Catalytic Reduction (SCR) Catalyst A mixture of distilled water and Fe-BEA zeolite (Fe content calculated as Fe2O3: 1.5 to 7.5 wt% based on the weight of the zeolite) was prepared, and a zirconia precursor was added as an additive. The amount of the zirconia precursor was calculated so that the amount of zirconia in the catalyst would be 1 to 5 wt% based on the weight of the coating. The solid content of the resulting mixture was 30 to 45%. The slurry was pulverized so as to obtain a Dv90 of 3 to 12 micrometers.

[0165] The resulting slurry was disposed over the entire length of an uncoated ceramic honeycomb flow-through substrate (diameter: 4.66 inches × length: 3 inches, cylindrical substrate having 400 / (2.54) 2 cells / square centimeter and a wall thickness of 0.08 millimeter (3 mils)), dried at 120 to 180 °C, and further fired in air at 400 to 600 °C. The SCR coating contains Fe-BEA zeolite and zirconia. The loading amount of the SCR coating was 2 to 4 g / in 3 It was.

[0166] Reference Example 6 Ammonia Oxidation (AMOx) Catalyst PGM-containing bottom coating: An aqueous mixture of a Pt precursor was impregnated in an aqueous medium onto a high surface area and porous oxide support such as alumina, preferably La-doped alumina (4 wt% La calculated as La2O3 based on the weight of the support). The resulting mixture had a solid content of 50 to 70%. This slurry was wet pulverized so as to obtain a Dv90 of 2 to 25 micrometers. Then, the resulting slurry was applied to an uncoated ceramic honeycomb flow-through substrate (diameter: 5.66 inches × length: 3 inches, 400 / (2.54) 2It was disposed over the entire length of a cylindrical substrate having a cell / square centimeter and a wall thickness of 0.1 millimeter (4 mils), dried at 120 to 180 °C, and fired in air at 400 to 600 °C. The loading of the PGM coating was 1 to 2 g / in 3 It was.

[0167] PGM-free top coating: A mixture of a zirconia precursor (calculated as ZrO2 based on the weight of the PGM-free coating, 2 to 5 wt%) and distilled water was prepared, and Fe-BEA zeolite (Fe content calculated as Fe2O3: 1.5 to 7.5 wt% based on the weight of the zeolite, silica-to-alumina molar ratio 6 to 15:1) was added to the mixture under constant mixing. The solid content of the resulting slurry was 20 to 40%. The slurry was dispersed and mixed so as to obtain a Dv90 of 2 to 12 micrometers. Then, the resulting slurry was disposed over the entire length of a substrate coated with a PGM-containing bottom coating, dried at 120 to 180 °C, and fired in air at 400 to 600 °C. The loading of the PGM-free coating was 1.5 to 3 g / in 3 It was.

[0168] Reference Example 7 Selective Catalytic Reduction (SCR) Catalyst A mixture of distilled water and Cu-CHA zeolite (Cu content calculated as CuO: 3.4 wt% based on the weight of the zeolite) was prepared, and a zirconia precursor was added as an additive. The amount of the zirconia precursor was calculated such that the amount of zirconia in the catalyst was 1 to 5 wt% based on the weight of the coating. The solid content of the resulting mixture was 42%. The slurry was pulverized so as to obtain a Dv90 of 3 to 12 micrometers.

[0169] The resulting slurry was applied to an uncoated ceramic honeycomb flow-through substrate (diameter: 4.66 inches × length: 3 inches, 400 / (2.54) 2It was disposed over the entire length of a cylindrical substrate having a cell / cm² and a wall thickness of 0.08 mm (3 mils), dried at 120 to 180 °C, and further fired in air at 400 to 600 °C. The SCR coating contains Cu-CHA zeolite and zirconia. The loading amount of the SCR coating was 2 g / in 3 There was.

[0170] Comparative Example 2 Exhaust gas treatment system not according to the present invention The exhaust gas treatment system of Comparative Example 2 includes the catalyst of Reference Example 1 (TWC catalyst) as Catalyst 1, the catalyst of Reference Example 2 (FWC catalyst) as Catalyst 2, and the catalyst of Reference Example 7 (SCR catalyst) as Catalyst 3. Catalyst 1 is positioned upstream of Catalyst 2, and Catalyst 2 is positioned upstream of Catalyst 3. There is no catalyst between Catalyst 1 and Catalyst 2 and between Catalyst 2 and Catalyst 3, and Catalyst 1 is a close-coupled catalyst.

[0171] Example 1 Exhaust gas treatment system according to the present invention The exhaust gas treatment system of Example 1 includes the catalyst of Reference Example 1 (TWC catalyst) as Catalyst 1, the catalyst of Reference Example 2 (FWC catalyst) as Catalyst 2, and the catalyst of Reference Example 3 (AMOx catalyst) as Catalyst 3. Catalyst 1 is positioned upstream of Catalyst 2, and Catalyst 2 is positioned upstream of Catalyst 3. There is no catalyst between Catalyst 1 and Catalyst 2 and between Catalyst 2 and Catalyst 3. Catalyst 1 is a close-coupled catalyst. This system is shown in FIG. 1.

[0172] Example 2 Exhaust gas treatment system according to the present invention The exhaust gas treatment system of Example 2 includes the catalyst of Reference Example 1 (TWC catalyst) as Catalyst 1, the catalyst of Reference Example 2 (FWC catalyst) as Catalyst 2, and the catalyst of Reference Example 4 (SCR / AMOx catalyst) as Catalyst 3. Catalyst 1 is positioned upstream of Catalyst 2, and Catalyst 2 is positioned upstream of Catalyst 3. There is no catalyst between Catalyst 1 and Catalyst 2 and between Catalyst 2 and Catalyst 3. Catalyst 1 is a close-coupled catalyst. This system is shown in FIG. 1.

[0173] Example 3 Exhaust gas treatment system according to the present invention The exhaust gas treatment system of Example 3 includes the catalyst of Reference Example 1 (TWC catalyst) as Catalyst 1, the catalyst of Reference Example 2 (FWC catalyst) as Catalyst 2, and the catalyst of Reference Example 5 (SCR catalyst) as Catalyst 3. Catalyst 1 is positioned upstream of Catalyst 2, and Catalyst 2 is positioned upstream of Catalyst 3. There is no catalyst between Catalyst 1 and Catalyst 2 and between Catalyst 2 and Catalyst 3. Catalyst 1 is a close-coupled catalyst. This system is shown in FIG. 1.

[0174] HC and NH3 tailpipe emissions under Example 4 WLTC - Tests of the systems according to Examples 1 to 3 and Comparative Example 1 In different systems, Catalyst 1 (TWC) and Catalyst 2 (FWC) are positioned in the same canister in combination with different downstream components in Comparative Example 1 and Examples 1 to 3. The comparative system including TWC and FWC having TWC downstream represents a standard Euro 6 configuration, and the system of the present invention composed of any one of AMOx, SCR, or a combination of both at the underfloor position downstream of TWC+FWC represents Euro 7 gasoline applications.

[0175] The systems evaluated were aged on an engine bench using a 2L Euro 6 engine such that the canning containing TWC+FWC was placed at the CC position and the components under evaluation (TWC, AMOx, SCR+AMOx or SCR) were placed downstream of separate canisters. The same CC unit was used upstream for all the systems studied. The aging was of the lambda 1 type with periodic fuel cut or lean / rich perturbation at a downstream catalyst inlet temperature of 830°C. The aging period was 20 hours. Thermocouples placed at different positions along the exhaust line were able to record the engine outlet, catalyst inlet, and floor temperatures.

[0176] The system and its resulting component evaluation (WLTC) were performed on a Euro 6 GTDI vehicle using a chassis dynamometer test cell. The latter has thermocouples and an FT-IR unit attached at the engine outlet / catalyst inlet, catalyst bed, and outlet positions, enabling accurate recording of the temperature and gaseous emissions along the exhaust line.

[0177] The data presented includes the cumulative HC and NH3 emissions (Figs. 2 - 3) for each system (Fig. 1) using the WLTC cycle collected on the vehicle described above.

[0178] As can be seen from Fig. 2, the cumulative HC emissions obtained in the comparative system are significantly higher compared to those of the system of the present invention, especially at low speeds and low temperatures up to 200 seconds in the WLTC cycle. The best results are obtained with a downstream configuration with only SCR containing the highest Fe - BEA loading, indicating that excellent low - temperature HC tailpipe reduction is directly related to the zeolite loading. Thus, in the system according to the present invention, under the evaluation conditions in the WLTC cycle, the overall HC emissions are significantly reduced. Finally, as can be seen from Fig. 3, the cumulative NH3 emissions are significantly higher in the comparative system compared to the novel system of the present invention. The best results are obtained with the AMOx downstream system, and the highest emissions are generated across the under - floor system with only SCR.

[0179] Therefore, it has been demonstrated that the system according to the present invention, which includes an AMOx catalyst or an SCR catalyst or both downstream of the TWC + FWC CC1 configuration, enables improvement in HC and NOx conversion. Without wishing to be bound by any theory, it is considered that the PGM - free zeolite coating at the downstream position plays an important role in the process.

[0180] Example 5 Exhaust gas treatment system according to the present invention The exhaust gas treatment system of Example 1 includes the catalyst of Reference Example 1 (TWC catalyst) as Catalyst 1, the catalyst of Reference Example 2 (FWC catalyst) as Catalyst 2, and the catalyst of Reference Example 6 (AMOx catalyst) as Catalyst 3. Catalyst 1 is positioned upstream of Catalyst 2, and Catalyst 2 is positioned upstream of Catalyst 3. There is no catalyst between Catalyst 1 and Catalyst 2 and between Catalyst 2 and Catalyst 3. Catalyst 1 is a close - coupled catalyst.

[0181] Example 6 HC and NH3 Tailpipe Emissions under WLTC - Testing of the Systems According to Example 3 and Comparative Example 2 In the different systems, catalyst 1 (TWC) and catalyst 2 (FWC) are positioned in the same canister in combination with different downstream components in Comparative Example 2 and Example 3. The comparative system includes a Cu-CHA SCR catalyst and Example 3 of the present invention includes an Fe-BEA SCR catalyst.

[0182] The systems evaluated were aged on an engine bench using a 2L Euro 6 engine such that the canning containing the TWC+FWC was placed in the CC position and the SCR component under evaluation was placed downstream of a separate canister. The same CC unit was used upstream for all the systems studied. The aging was of the lambda 1 type with periodic fuel cut or lean / rich perturbations at a downstream catalyst inlet temperature of 820 °C. The aging period was 80 hours. Thermocouples placed at different positions along the exhaust line were able to record the engine outlet, catalyst inlet and bed temperatures.

[0183] The system and its resulting component evaluation (WLTC) were carried out on a Euro 6 GTDI vehicle using a chassis dynamometer test cell. The latter had thermoelements and an FT-IR unit attached at the engine outlet / catalyst inlet, catalyst bed and outlet positions, enabling accurate recording of the temperature and gaseous emissions along the exhaust line.

[0184] The data presented includes the cumulative NH3, CO and N2O (Figures 4 - 6) emissions for each system (Figure 1) using the WLTC cycle collected on the vehicle described above. As can be seen from Figures 4 - 6, the cumulative NH3, CO and N2O emissions are significantly higher in Comparative Example 2 compared to Example 3 of the present invention.

[0185] Therefore, it has been demonstrated that the system according to the present invention including an Fe-BEA SCR catalyst downstream of the TWC+FWC CC1 configuration enables improvement in NH3, CO and N2O conversion.

Claims

1. An exhaust gas treatment system for processing the exhaust gas flow from a gasoline engine, wherein the exhaust gas treatment system has an upstream end for introducing the exhaust gas flow into the exhaust gas treatment system, and the exhaust gas treatment system is (i) A ternary conversion catalyst having an inlet end and an outlet end, comprising a coating disposed on a substrate, wherein the coating comprises a platinum group metal component supported on a porous oxide material, and (ii) A quaternary transformer catalyst having an inlet end and an outlet end, comprising a coating disposed on a wall flow filter substrate, wherein the coating comprises a platinum group metal component supported on a porous oxide material, and (iii) A third catalyst having an inlet end and an outlet end, wherein the third catalyst comprises a substrate and a coating for selective catalytic reduction of NOx, the SCR coating comprises a zeolite material comprising one or more of Fe and Cu, and the SCR coating comprises up to 0.0001% by weight of platinum group metals, The first catalyst according to (i) is a first catalyst of the exhaust gas treatment system located downstream of the upstream end of the exhaust gas treatment system, and the inlet end of the first catalyst is located upstream of the outlet end of the first catalyst. In the exhaust gas treatment system, the second catalyst according to (ii) is located downstream of the first catalyst according to (i), and the inlet end of the second catalyst is located upstream of the outlet end of the second catalyst. The exhaust gas treatment system wherein the third catalyst according to (iii) is located downstream of the second catalyst according to (ii), and the inlet end of the third catalyst is located upstream of the outlet end of the third catalyst.

2. The exhaust gas treatment system according to claim 1, wherein the porous oxide material supporting the platinum group metal component of the coating of the first catalyst is selected from the group consisting of alumina, ceria, silica, zirconia, titania, two or more mixtures thereof, and two or more mixed oxides thereof, preferably selected from the group consisting of alumina, titania, zirconia, two or more mixtures thereof, and two or more mixed oxides thereof, more preferably selected from the group consisting of alumina, zirconia, two mixtures thereof, and two mixed oxides thereof, and more preferably alumina.

3. The exhaust gas treatment system according to claim 1 or 2, wherein the coating of the first catalyst further comprises an oxygen storage component, the oxygen storage component preferably comprises cerium, more preferably one or more of cerium oxide, a mixture of oxides containing cerium oxide, and a mixed oxide containing cerium, the mixed oxide containing cerium more preferably comprises one or more of zirconium, yttrium, neodymium, lanthanum, hafnium, samarium, and praseodymium, more preferably one or more of zirconium, yttrium, neodymium, lanthanum, and praseodymium, and more preferably further comprises zirconium.

4. The exhaust gas treatment system according to claim 3, wherein in the coating of the first catalyst, the weight ratio of the porous oxide material to the oxygen storage component defined in claim 3 is in the range of 1:1 to 10:1, preferably in the range of 1:1 to 5:

1.

5. The exhaust gas treatment system according to claim 1 or 2, wherein the coating of the first catalyst further comprises an alkaline earth metal oxide, the alkaline earth metal preferably selected from the group consisting of barium, strontium, and magnesium, more preferably selected from the group consisting of barium and strontium, and more preferably barium.

6. The exhaust gas treatment system according to claim 1 or 2, wherein the coating of the second catalyst further comprises an oxygen storage component (OSC), the oxygen storage component preferably comprises cerium, more preferably one or more of cerium oxide, a mixture of oxides containing cerium oxide, and a mixed oxide containing cerium, the mixed oxide containing cerium more preferably comprises one or more of zirconium, yttrium, neodymium, lanthanum, hafnium, samarium, and praseodymium, more preferably one or more of zirconium, yttrium, neodymium, lanthanum, and praseodymium, and more preferably further comprises zirconium.

7. The exhaust gas treatment system according to claim 1 or 2, wherein the zeolite material of the SCR coating of the third catalyst is a 12-membered ring-pore zeolite material, and the 12-membered ring-pore zeolite material preferably has a skeletal type selected from the group consisting of BEA, MOR, FAU, GME, OFF, mixtures of two or more of them, and mixed types of two or more of them, more preferably has a skeletal type selected from the group consisting of BEA, MOR, FAU, mixtures of two or more of them, and mixed types of two or more of them, more preferably has a skeletal type selected from the group consisting of BEA and FAU, and more preferably has a skeletal type BEA included in the SCR coating of the third catalyst.

8. The exhaust gas treatment system according to claim 7, wherein the zeolite material included in the SCR coating of the third catalyst is a 12-membered ring-pore zeolite material, and the zeolite material contains Fe.

9. The exhaust gas treatment system according to claim 1 or 2, wherein the third catalyst comprises the substrate and the SCR coating.

10. The exhaust gas treatment system according to claim 1 or 2, wherein the third catalyst includes an ammonia oxidation catalyst (AMOx) coating in addition to the SCR coating.

11. The exhaust gas treatment system according to claim 10, wherein the SCR coating of the third catalyst comprises a zeolite material, preferably consisting of a zeolite material, the zeolite material preferably having a skeletal BEA, and comprising iron and a non-zeolite oxide material, preferably ceria.

12. The exhaust gas treatment system according to claim 10, wherein the AMOx coating of the third catalyst further comprises a zeolite material containing a platinum group metal, preferably one or more of Pt, Pd and Rh, more preferably one or more of Pt and Pd, more preferably Pt, and one or more of Fe and Cu, preferably a zeolite material containing Fe.

13. The exhaust gas treatment system according to claim 10, wherein the AMOx coating of the third catalyst preferably comprises a porous oxide material for supporting the platinum group metal as defined in claim 11, the porous oxide material being selected from the group consisting of titania, alumina, ceria, silica, zirconia, two or more mixtures thereof, and two or more mixed oxides thereof, preferably selected from the group consisting of titania, alumina, and silica, and more preferably titania.

14. The exhaust gas treatment system according to claim 13, insofar as it is dependent on claim 11, wherein in the AMOx coating, the weight ratio of the zeolite material containing one or more of Fe and Cu to the porous oxide material is in the range of 0.5:1 to 2:1, preferably in the range of 0.75:1 to 1.5:1, and more preferably in the range of 1:1 to 1.25:

1.

15. The exhaust gas treatment system according to claim 10, wherein the AMOx coating is disposed on the substrate of the third catalyst over 98 to 100%, preferably 99 to 100%, more preferably 99.5 to 100% of the axial length of the substrate, and the SCR coating is disposed on the AMOx coating over 98 to 100%, preferably 99 to 100%, more preferably 99.5 to 100% of the axial length of the substrate.

16. The third catalyst includes an inlet zone containing the SCR coating, preferably consisting of the SCR coating, and an outlet zone containing the ammonia oxidation catalyst coating, preferably consisting of the ammonia oxidation catalyst coating. The AMOx coating in the aforementioned exit zone is - A first coat comprising a platinum group metal supported on a porous oxide material, preferably titania, and a zeolite material containing one or more of Fe and Cu, preferably further comprising a non-zeolite oxide material, wherein the non-zeolite oxide material more preferably comprises one or more of zirconia, alumina, ceria, titania, silica, and a mixed oxide containing two or more of Zr, Al, Ce, Ti, and Si, - A second coat comprising a zeolite material containing one or more of Fe and Cu, wherein the first coat comprises a maximum of 0.0001% by weight of platinum group metals, The exhaust gas treatment system according to claim 1 or 2, wherein the first coat is disposed on the substrate over the length of the outlet zone, and the second coat is disposed on the first coat over the length of the outlet zone, or the second coat is disposed on the substrate over the length of the outlet zone, and the first coat is disposed on the second coat over the length of the outlet zone.

17. The exhaust gas treatment system according to claim 1 or 2, wherein the third catalyst includes an oxidation catalyst coating in addition to the SCR coating, the oxidation catalyst coating of the third catalyst includes a platinum group metal, and up to 0.01% by weight of the oxidation catalyst coating of the third catalyst consists of a zeolite material.

18. A method for the simultaneous selective catalytic reduction of NOx, oxidation of hydrocarbons, oxidation of nitric oxide, and oxidation of ammonia, (1) To provide an exhaust gas flow from a gasoline engine containing one or more of NOx, ammonia, nitric oxide, and hydrocarbons, (2) A method comprising passing the exhaust gas flow provided in (1) through the exhaust gas system according to claim 1 or 2.

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