Novel tin-containing catalyst for gasoline engine exhaust gas treatment

Abstract

A three-way catalyst article and its use in an exhaust system for an internal combustion engine is disclosed. The catalyst article for treating exhaust gases includes a substrate including an inlet end and an outlet end having an axial length L, and a first catalyst region including a first platinum group metal (PGM) component and a first PGM support material, the first catalyst region including up to 5 wt.% Sn.

Description

Technical Field

[0001] The present invention relates to a catalyst article useful for treating exhaust gas emissions from gasoline engines.

Background Art

[0002] In internal combustion engines, exhaust gases containing various pollutants including hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (nitrogen oxide, "NO x ") are generated. Emission control systems including exhaust gas catalytic conversion catalysts are widely used to reduce the amount of these pollutants emitted into the atmosphere. The catalyst commonly used for the exhaust treatment of gasoline engines is a TWC (three way catalyst). The TWC performs the following three main functions: (1) oxidation of CO, (2) oxidation of unburned HC, and (3) reduction of NO x .

[0003] Despite the progress of TWC technology, there is still a need for improved catalytic converters for specific engine platforms that simultaneously improve performance during the cold start phase, provide better light off performance, and provide better OSC performance in a wide range of Pd and / or Pt applications during the hot transient phase. The present invention particularly solves these problems.

Summary of the Invention

[0004] One aspect of the present disclosure is a catalyst composition comprising a platinum group metal (PGM) component and a PGM support material, the catalyst composition being targeted and containing up to 5 wt% Sn.

[0005] Another aspect of the present disclosure relates to a catalyst article for treating exhaust gases, comprising: a substrate including an inlet end and an outlet end having an axial length L; and a first catalyst region comprising a first platinum group metal (PGM) component and a first PGM carrier material, the first catalyst region comprising up to 5% by weight of Sn.

[0006] The present invention also encompasses an exhaust system for an internal combustion engine that includes the three-way catalytic converter component of the present invention.

[0007] The present invention also encompasses the treatment of exhaust gases from internal combustion engines, particularly from gasoline engines. The method includes contacting the exhaust gas with the three-way catalytic converter components of the present invention. [Brief explanation of the drawing]

[0008] [Figure 1] An embodiment of the present invention is shown, which includes a first catalyst region (single layer) having a length of 100% of the axial length L of the substrate. [Figure 2a] An embodiment of the present invention is shown, in which a first catalyst region extends as a bottom layer to 100% of the axial length L, and a second catalyst region extends as an upper layer to 100% of the axial length L. [Figure 2b] A modified version of Figure 2a is shown. [Figure 3a] An embodiment of the present invention is shown in which a first catalyst region extends from the inlet end to less than 100% of the axial length L, and a second catalyst region extends from the outlet end to less than 100% of the axial length L. The total length of the second and first catalyst regions is less than or equal to the axial length L. [Figure 3b] A modified example of Figure 3a is shown. [Figure 3c] An embodiment of the present invention is shown in which a first catalyst region extends from the inlet end to less than 100% of the axial length L, and a second catalyst region extends from the outlet end to less than 100% of the axial length L. The total length of the second and first catalyst regions is greater than the axial length L. [Figure 3d] A modified example of Figure 3c is shown. [Figure 4a] An embodiment of the present invention is shown in which a first catalyst region extends from the inlet end to less than 100% of the axial length L, and a second catalyst region extends from the outlet end to less than 100% of the axial length L. The total length of the second and first catalyst regions is less than or equal to the axial length L. A third catalyst region extends to 100% of the axial length L and overlaps the first and second catalyst regions as an upper layer. [Figure 4b] A modified example of Figure 4a is shown. [Figure 4c] An embodiment of the present invention is shown in which a third catalyst region extends as a bottom layer to 100% of the axial length L. An embodiment of the present invention is shown in which a first catalyst region extends from the inlet end to less than 100% of the axial length L, and a second catalyst region extends from the outlet end to less than 100% of the axial length L. The total length of the second and first catalyst regions is less than or equal to the axial length L. [Figure 4d] A modified example of Figure 4c is shown. [Figure 5a] An embodiment of the present invention is shown in which a first catalyst region extends from the inlet end to less than 100% of the axial length L, and a second catalyst region extends from the outlet end to less than 100% of the axial length L. The total lengths of the second and first catalyst regions may be less than the axial length L, equal to the axial length L, or greater than the axial length L. A third catalyst region extends from the inlet end to less than 100% of the axial length L, and a fourth catalyst region extends from the outlet end to less than 100% of the axial length L. The total lengths of the third and fourth catalyst regions may be less than the axial length L, equal to the axial length L, or greater than the axial length L. The first and second catalyst regions constitute the bottom layer, and the third and fourth catalyst regions constitute the upper layer. [Figure 5b] A modified example of Figure 5a is shown. [Figure 5c] A modified example of Figure 5a is shown. [Figure 5d] A modified example of Figure 5a is shown. [Figure 6a]An embodiment of the present invention is shown, in which a first catalyst region extends as a bottom layer to 100% of the axial length L, a second catalyst region extends as an intermediate layer to 100% of the axial length L, and a third catalyst region extends as an upper layer to 100% of the axial length L. [Figure 6b] A modified version of Figure 6a is shown. [Figure 6c] A modified version of Figure 6a is shown. [Figure 7a] An embodiment of the present invention is shown in which a first catalyst region extends from the inlet end to less than 100% of the axial length L, and a second catalyst region extends from the outlet end to less than 100% of the axial length L. The total length of the second and first catalyst regions is greater than the axial length L. A third catalyst region extends to 100% of the axial length L and overlaps the first and second catalyst regions as an upper layer. [Figure 7b] A modified example of Figure 7a is shown below. [Figure 7c] A modified example of Figure 7a is shown below. [Figure 7d] A modified example of Figure 7a is shown below. [Figure 7e] A modified example of Figure 7a is shown below. [Figure 7f] A modified example of Figure 7a is shown below. [Figure 7g] An embodiment of the present invention is shown in which a first catalyst region extends from the inlet end to less than 100% of the axial length L, and a second catalyst region extends from the outlet end to less than 100% of the axial length L. The total lengths of the second and first catalyst regions may be less than the axial length L, equal to the axial length L, or greater than the axial length L. A third catalyst region extends from the inlet end to less than 100% of the axial length L and at least partially overlaps the first and / or second catalyst regions. [Figure 7h] A modified example of Figure 7g is shown. [Figure 7i] A modified example of Figure 7g is shown. [Figure 7j]An embodiment of the present invention is shown in which a first catalyst region extends from the inlet end to less than 100% of the axial length L, and a second catalyst region extends from the outlet end to less than 100% of the axial length L. The total lengths of the second and first catalyst regions may be less than the axial length L, equal to the axial length L, or greater than the axial length L. A third catalyst region extends from the outlet end to less than 100% of the axial length L and at least partially overlaps the second and / or first catalyst regions. [Figure 7k] A modified example of Figure 7j is shown below. [Figure 7l] A modified example of Figure 7j is shown below. [Modes for carrying out the invention]

[0009] The present invention relates to catalytic treatment of combustion exhaust gases, such as those produced by gasoline engines and other engines, and to related catalytic compositions, catalytic articles, and systems. More specifically, the present invention relates to NO in vehicle exhaust systems. x This invention relates to the simultaneous treatment of CO and HC. While most technological developments to improve the thermal endurance of TWCs have focused on increasing the specific surface area (SSA) of the OSC material after thermal aging, the inventors have surprisingly discovered that enhancing the OSC function over a wide temperature range, facilitated by Sn doping, has a significant impact on the improved thermal endurance of TWCs and the resulting emissions control performance. The inventors have found that the potential performance of TWCs under light-off and OSC tests, as well as their substantial performance under several emissions control tests, is improved in this invention. The process of this invention also reduces the cost of the catalyst.

[0010] One aspect of the present disclosure relates to a catalyst composition comprising a platinum group metal (PGM) component and a PGM support material, wherein the catalyst composition contains up to 5% by weight of Sn.

[0011] Through thorough research, the inventors discovered that by incorporating a small amount of tin (Sn) into the TWC catalyst composition, these novel compositions exhibit superior catalytic properties (for example, by using the tin-containing catalyst described in the present invention, all emissions (THC / NMHC, CO, and NO) are reduced during vehicle testing). x Emissions were significantly reduced. Furthermore, the introduction of tin into the TWC catalyst composition improves the dispersion and stabilization of PGMs after hash aging.

[0012] Throughout this application, "weight % of Sn" is calculated based on SnO2.

[0013] The PGM component can be selected from the group consisting of platinum, palladium, rhodium, and combinations thereof. In some embodiments, the PGM component may be Pd, Rh, or a mixture thereof. In other embodiments, the PGM component may be platinum. In yet other embodiments, the PGM component may be platinum and rhodium; palladium and rhodium; or platinum, palladium, and rhodium.

[0014] The PGM support material may be an oxygen storage capacity (OSC) material, an inorganic oxide, or a combination thereof.

[0015] OSC materials may be cerium oxide, zirconium oxide, ceria-zirconia mixed oxide, alumina-ceria-zirconia mixed oxide, or a combination thereof. More preferably, OSC materials include ceria-zirconia mixed oxide, alumina-ceria-zirconia mixed oxide, or a combination thereof. Ceria-zirconia mixed oxide may further contain dopants such as lanthanum, neodymium, praseodymium, and yttrium oxide. In addition, OSC materials may function as carrier materials for PGM components. In some embodiments, OSC materials include ceria-zirconia mixed oxide and alumina-ceria-zirconia mixed oxide.

[0016] The inorganic oxides are preferably oxides of elements from Groups 2, 3, 4, 5, 13, and 14. The inorganic oxides are preferably selected from the group consisting of alumina, magnesia, silica, zirconia, barium oxide, and mixed or composite oxides thereof. Particularly preferred are alumina, lanthanum-alumina, zirconia, or magnesia / alumina composite oxides. One particularly preferred inorganic oxide is alumina or lanthanum-alumina.

[0017] The OSC material and the inorganic oxide can have a weight ratio of 10:1 or less, preferably 8:1 or 5:1 or less, more preferably 4:1 or 3:1 or less, and most preferably 2:1 or less.

[0018] Alternatively, the weight ratio of the OSC material to the inorganic oxide can be 10:1 to 1:10, preferably 8:1 to 1:8 or 5:1 to 1:5, more preferably 4:1 to 1:4 or 3:1 to 1:3, and most preferably 2:1 to 1:2.

[0019] In some embodiments, the OSC material and the inorganic oxide may have a weight ratio of 2:1 or less. In further embodiments, the OSC material and the inorganic oxide may have a weight ratio of 10:1 or less. In yet another further embodiment, the OSC material and the inorganic oxide may have a weight ratio of 20:1 or more, or 30:1 or more. In yet another further embodiment, the OSC material and the inorganic oxide may have a weight ratio of 40:1 or more, or 50:1 or more.

[0020] The catalyst composition may further contain an alkali or an alkaline earth metal.

[0021] The alkali or alkaline earth metal is preferably barium or strontium, and mixed or composite oxides thereof. Preferably, if present, the barium or strontium is packed in an amount of 0.1 to 15% by weight, more preferably 3 to 10% by weight, based on the total weight of the catalyst composition.

[0022] Preferably, barium or strontium exists as BaCO3 or SrCO3. Such materials can be produced by any method known in the art, for example, by initial wetting impregnation or spray drying.

[0023] Tin (Sn) can be incorporated into catalyst compositions in various ways. In some embodiments, Sn may be incorporated as a dopant into an OSC material, which may contain up to 5% by weight of Sn, preferably up to 4% by weight of Sn, more preferably up to 3% by weight of Sn, and even more preferably up to 2% by weight of Sn, based on the total weight of the OSC material. Alternatively, the OSC material may contain 0.1 to 5% by weight of Sn, preferably up to 0.1 to 4% by weight of Sn, more preferably up to 0.1 to 3% by weight of Sn, and even more preferably up to 0.1 to 2.5% by weight of Sn, based on the total weight of the OSC material. In other embodiments, Sn may be incorporated as a dopant into an inorganic oxide, which may contain up to 5% by weight of Sn, preferably up to 4% by weight of Sn, more preferably up to 3% by weight of Sn, and even more preferably up to 2% by weight of Sn, based on the total weight of the inorganic oxide. Alternatively, the inorganic oxide may contain 0.1 to 5 wt% Sn, preferably 0.2 to 4 wt% Sn, more preferably 0.3 to 3 wt% Sn, and even more preferably 0.4 to 2 wt% Sn, based on the total weight of the inorganic oxide. In yet another embodiment, Sn may be incorporated into the catalyst composition as a simple physical mixture. For example, Sn may be incorporated as SnO2 so as to be physically blended with the OSC material and / or inorganic oxide, and the catalyst composition may contain up to 5 wt% Sn, preferably up to 4 wt% Sn, more preferably up to 3 wt% Sn, and even more preferably up to 2 wt% Sn, based on the total weight of the catalyst composition. Alternatively, the catalyst composition may contain 0.1 to 5 wt% Sn, preferably 0.2 to 4 wt% Sn, more preferably 0.3 to 3 wt% Sn, and even more preferably 0.4 to 2 wt% Sn, based on the total weight of the catalyst composition. In another embodiment, Sn may be incorporated into the OSC material framework. In other embodiments, Sn may be incorporated into the OSC material framework (for example, Sn may be doped into the crystal lattice of the formed OSC solid solution material), and the OSC material framework may contain up to 5 wt% Sn, preferably up to 4 wt% Sn, more preferably up to 3 wt% Sn, and even more preferably up to 2 wt% Sn.Alternatively, the OSC material may contain 0.1 to 5% by weight of Sn, preferably 0.1 to 4% by weight of Sn, more preferably 0.1 to 3% by weight of Sn, and even more preferably 0.1 to 2.5% by weight of Sn, based on the total weight of the OSC material.

[0024] In some embodiments, the catalyst composition may contain up to 5% by weight of Sn, preferably up to 3% by weight of Sn, more preferably up to 2% by weight of Sn, most preferably up to 1% by weight or 0.5% by weight of Sn, based on the total weight of the catalyst composition. Alternatively, the catalyst composition may contain 0.1 to 5% by weight of Sn, preferably 0.1 to 4% by weight of Sn, more preferably 0.2 to 3% by weight of Sn, and even more preferably 0.4 to 1.5% by weight of Sn, based on the total weight of the catalyst composition.

[0025] As illustrated in the following embodiments, the catalyst composition in this embodiment can be applied as a TWC catalyst for treating exhaust gases generated by a gasoline engine.

[0026] Another aspect of the present disclosure is a catalyst article for treating exhaust gas, comprising: a substrate including an inlet end and an outlet end having an axial length L; and a first catalyst region comprising a first platinum group metal (PGM) component and a first PGM carrier material, the first catalyst region comprising up to 5% by weight of Sn.

[0027] First catalytic region The first PGM component can be selected from the group consisting of platinum, palladium, rhodium, and mixtures thereof. In some embodiments, the first PGM component may be Pd, Rh, or mixtures thereof. In other embodiments, the first PGM component may be platinum. In yet another embodiment, the first PGM component may be platinum and rhodium; palladium and rhodium; or platinum, palladium, and rhodium. In yet another embodiment, the first PGM component may be platinum and rhodium; or platinum, palladium, and rhodium.

[0028] The first PGM support material may be a first oxygen storage capacity (OSC) material, a first inorganic oxide, or a combination thereof.

[0029] The first OSC material may be cerium oxide, zirconium oxide, ceria-zirconia mixed oxide, alumina-ceria-zirconia mixed oxide, or a combination thereof. More preferably, the first OSC material includes ceria-zirconia mixed oxide, alumina-ceria-zirconia mixed oxide, or a combination thereof. The ceria-zirconia mixed oxide may further contain dopants such as lanthanum, neodymium, praseodymium, or yttrium oxide. The first OSC material may function as a carrier material for a first PGM component (e.g., as a first PGM carrier material). In some embodiments, the first OSC material includes ceria-zirconia mixed oxide and alumina-ceria-zirconia mixed oxide.

[0030] The first inorganic oxide is preferably an oxide of an element from Group 2, Group 3, Group 4, Group 5, Group 13, and Group 14. The first inorganic oxide is preferably selected from the group consisting of alumina, magnesia, silica, zirconia, barium oxide, and mixed or composite oxides thereof. Particularly preferred is the first inorganic oxide being alumina, lanthanum-alumina, zirconia, or a magnesia / alumina composite oxide. One particularly preferred first inorganic oxide is alumina or lanthanum-alumina.

[0031] The first OSC material and the first inorganic oxide may have a weight ratio of 10:1 or less, preferably 8:1 or 5:1 or less, more preferably 4:1 or 3:1 or less, and most preferably 2:1 or less.

[0032] Alternatively, the weight ratio of the first OSC material to the first inorganic oxide can be 10:1 to 1:10, preferably 8:1 to 1:8 or 5:1 to 1:5, more preferably 4:1 to 1:4 or 3:1 to 1:3, and most preferably 2:1 to 1:2.

[0033] In some embodiments, the first OSC material and the first inorganic oxide may have a weight ratio of 2:1 or less. In further embodiments, the first OSC material and the first inorganic oxide may have a weight ratio of 10:1 or less. In yet another further embodiment, the first OSC material and the first inorganic oxide may have a weight ratio of 20:1 or more, or 30:1 or more. In yet another further embodiment, the first OSC material and the first inorganic oxide may have a weight ratio of 40:1 or more, or 50:1 or more.

[0034] The first catalyst region may further contain a first alkali or alkaline earth metal.

[0035] The first alkali metal or alkaline earth metal is preferably barium or strontium, and mixed oxides or composite oxides thereof. Preferably, if present, the barium or strontium is packed in an amount of 0.1 to 15% by weight, more preferably 3 to 10% by weight, based on the total weight of the first catalyst region.

[0036] Preferably, barium or strontium exists as BaCO3 or SrCO3. Such materials can be produced by any method known in the art, for example, by initial wetting impregnation or spray drying.

[0037] Tin (Sn) can be incorporated into the first catalyst region in various ways. In some embodiments, Sn can be incorporated into the first OSC material as a dopant, and the first OSC material may contain up to 5 wt% of Sn, preferably up to 4 wt% of Sn, more preferably up to 3 wt% of Sn, and even more preferably up to 2 wt% of Sn, based on the total weight of the first OSC material. Alternatively, the first OSC material may contain 0.1 to 5 wt% of Sn, preferably 0.1 to 4 wt% of Sn, more preferably 0.1 to 3 wt% of Sn, and even more preferably 0.1 to 2.5 wt% of Sn, based on the total weight of the first OSC material. In other embodiments, Sn may be incorporated into the first inorganic oxide as a dopant, the first inorganic oxide may contain up to 5 wt% Sn, preferably up to 4 wt% Sn, more preferably up to 3 wt% Sn, and even more preferably up to 2 wt% Sn, based on the total weight of the first inorganic oxide. Alternatively, the first inorganic oxide may contain 0.1 to 5 wt% Sn, preferably 0.2 to 4 wt% Sn, more preferably 0.3 to 3 wt% Sn, and even more preferably 0.4 to 2 wt% Sn, based on the total weight of the first inorganic oxide. In yet another embodiment, Sn may be incorporated into the first catalytic region as a simple physical mixture (e.g., a physical blend). For example, Sn may be incorporated as SnO2 so as to be physically blended with the first OSC material and / or the first inorganic oxide, and the first catalyst region may contain up to 5 wt% Sn, preferably up to 4 wt% Sn, more preferably up to 3 wt% Sn, and even more preferably up to 2 wt% Sn, based on the total weight of the first catalyst region. Alternatively, the first catalyst region may contain 0.1 to 5 wt% Sn, preferably 0.2 to 4 wt% Sn, more preferably 0.3 to 3 wt% Sn, and even more preferably 0.4 to 2 wt% Sn, based on the total weight of the first catalyst region.In other embodiments, Sn may be incorporated into the first OSC material framework (for example, Sn may be doped into the crystal lattice of the formed OSC solid solution material), and the first OSC material framework may contain up to 5 wt% of Sn, preferably up to 4 wt% of Sn, more preferably up to 3 wt% of Sn, and even more preferably up to 2 wt% of Sn. Alternatively, the OSC material may contain 0.1 to 5 wt% of Sn, preferably 0.1 to 4 wt% of Sn, more preferably 0.1 to 3 wt% of Sn, and even more preferably 0.1 to 2.5 wt% of Sn, based on the total weight of the first OSC material.

[0038] In some embodiments, the first catalyst region may contain up to 5 wt% of Sn, preferably up to 3 wt% of Sn, more preferably up to 2 wt% of Sn, and most preferably up to 1.5 wt% or 1 wt% of Sn, based on the total weight of the first catalyst region. Alternatively, the first catalyst region may contain 0.1 to 5 wt% of Sn, preferably 0.2 to 4 wt% of Sn, more preferably 0.3 to 3 wt% of Sn, and even more preferably 0.4 to 1.5 wt% of Sn, based on the total weight of the first catalyst region.

[0039] As illustrated in the following embodiments, the catalyst article in this embodiment can be applied as a TWC catalyst for treating exhaust gases generated by a gasoline engine.

[0040] The first catalyst region can extend over 100 percent of the axial length L (see, for example, Figures 1, 2a, 2b, and 6a-6c). In some embodiments, the first catalyst region can extend over 20-99%, 30-90%, or 40-80% of the axial length L. Alternatively, the first catalyst region can extend over 30-70 percent of the axial length L. Preferably, it can extend over 40-60 percent, more preferably 45-55 percent of the axial length L (see, for example, Figures 3a-5d and 7a-7l).

[0041] The total washcoat loading amount of the first catalyst region is less than 3.5 g / in 3 and preferably less than 3.0 g / in 3 or less than 2.5 g / in 3 The total washcoat loading amount of the first catalyst region can be from 0.5 to 3.5 g / in 3 preferably from 0.6 to 3 g / in 3 or from 0.7 to 2.5 g / in 3 The catalyst article can further include a second catalyst region.

[0042] Second catalyst region The catalyst article can further include a second catalyst region.

[0043] The second catalyst region can further include a second PGM component, a second oxygen storage capacity (OSC) material, a second alkali or alkaline earth metal component, and / or a second inorganic oxide.

[0044] The second PGM component can be selected from the group consisting of platinum, palladium, rhodium, and mixtures thereof. In some embodiments, the second PGM component can be Pd, Rh, or a mixture thereof.

[0045] The second OSC material can be cerium oxide, zirconium oxide, a ceria - zirconia mixed oxide, an alumina - ceria - zirconia mixed oxide, or a combination thereof. More preferably, the second OSC material includes a ceria - zirconia mixed oxide, an alumina - ceria - zirconia mixed oxide, or a combination thereof. Additionally, the second OSC material can further include one or more of dopants such as lanthanum, neodymium, praseodymium, yttrium, etc. Further, the second OSC material can function as a carrier material for the second PGM component. In some embodiments, the second OSC material includes a ceria - zirconia mixed oxide and an alumina - ceria - zirconia mixed oxide.

[0046] The ceria-zirconia mixed oxide can have a zirconia-to-ceria weight ratio of at least 50:50, preferably greater than 60:40, and more preferably greater than 70:30. Alternatively, the ceria-zirconia mixed oxide can also have a ceria-to-zirconia weight ratio of less than 50:50, preferably less than 40:60, and more preferably less than 30:70.

[0047] The second OSC material (e.g., ceria-zirconia mixed oxide) may be 10 to 90% by weight, preferably 25 to 75% by weight, and more preferably 30 to 60% by weight, based on the total wash coat load of the second catalyst region.

[0048] The amount of the second OSC material supported in the second catalyst region is 2 g / in. 3 It may be less than 1.5 g / in. In some embodiments, the amount of the second OSC material supported in the second catalyst region is 1.5 g / in. 3 , 1.2g / in 3 , 1g / in 3 , 0.8g / in 3 , or 0.7g / in 3 The following applies:

[0049] The second alkali metal or alkaline earth metal is preferably barium, strontium, a mixed oxide or composite oxide thereof. Preferably, if present, the amount of barium or strontium is 0.1 to 15% by weight, more preferably 3 to 10% by weight, based on the total weight of the second catalyst region.

[0050] The second alkali metal or alkaline earth metal is more preferably strontium. If present, strontium is preferably present in an amount of 0.1 to 15% by weight, more preferably 3 to 10% by weight, based on the total weight of the second catalyst region.

[0051] Furthermore, the second alkali metal or alkaline earth metal is preferably a mixed oxide or composite oxide of barium and strontium. Preferably, the mixed oxide or composite oxide of barium and strontium is present in an amount of 0.1 to 15% by weight, more preferably 3 to 10% by weight, based on the total weight of the second catalyst region. The second alkali metal or alkaline earth metal is more preferably a composite oxide of barium and strontium.

[0052] Preferably, barium or strontium exists as BaCO3 or SrCO3. Such materials can be produced by any method known in the art, for example, by initial wetting impregnation or spray drying.

[0053] The second inorganic oxide is preferably an oxide of an element from Group 2, Group 3, Group 4, Group 5, Group 13, and Group 14. The second inorganic oxide is preferably selected from the group consisting of alumina, magnesia, silica, zirconia, barium oxide, and mixed or composite oxides thereof. Particularly preferred are alumina, lanthanum-alumina, zirconia, or magnesia / alumina composite oxides. One particularly preferred second inorganic oxide is alumina or lanthanum-alumina.

[0054] The weight ratio of the second OSC material to the second inorganic oxide can be 10:1 or less, preferably 8:1 or 5:1 or less, more preferably 4:1 or 3:1 or less, and most preferably 2:1 or less.

[0055] Alternatively, the second OSC material and the second inorganic oxide can have a weight ratio of 10:1 to 1:10, preferably 8:1 to 1:8 or 5:1 to 1:5, more preferably 4:1 to 1:4 or 3:1 to 1:3, and most preferably 2:1 to 1:2.

[0056] In some embodiments, the second OSC material and the second inorganic oxide may have a weight ratio of 2:1 or higher. In further embodiments, the second OSC material and the second inorganic oxide may have a weight ratio of 10:1 or higher. In yet another further embodiment, the second OSC material and the second inorganic oxide may have a weight ratio of 20:1 or higher or 30:1 or higher. In yet another further embodiment, the second OSC material and the second inorganic oxide may have a weight ratio of 40:1 or higher or 50:1 or higher.

[0057] The total wash coat load in the second catalyst region is 3.5 g / in. 3 Less than 3.0 g / in 3 or 2.5g / in 3 It may be less than 0.5 to 3.5 g / in. The total wash coat load in the first catalyst region is 0.5 to 3.5 g / in. 3 Preferably, 0.6 to 3 g / in 3 Or 0.7-2.5 g / in 3 It is possible.

[0058] In some embodiments, the second catalyst region may contain up to 5% by weight of Sn.

[0059] Tin (Sn) can be incorporated into the second catalytic region in various ways. In some embodiments, Sn can be incorporated into the second OSC material as a dopant, and the second OSC material may contain up to 5 wt% of Sn, preferably up to 4 wt% of Sn, more preferably up to 3 wt% of Sn, and even more preferably up to 2 wt% of Sn, based on the total weight of the second OSC material. Alternatively, the second OSC material may contain 0.1 to 5 wt% of Sn, preferably 0.2 to 4 wt% of Sn, more preferably 0.3 to 3 wt% of Sn, and even more preferably 0.4 to 2 wt% of Sn, based on the total weight of the second OSC material. In other embodiments, Sn may be incorporated into the second inorganic oxide as a dopant, the second inorganic oxide may contain up to 5 wt% Sn, preferably up to 4 wt% Sn, more preferably up to 3 wt% Sn, and even more preferably up to 2 wt% Sn, based on the total weight of the second inorganic oxide. Alternatively, the second inorganic oxide may contain 0.1 to 5 wt% Sn, preferably 0.2 to 4 wt% Sn, more preferably 0.3 to 3 wt% Sn, and even more preferably 0.4 to 2 wt% Sn, based on the total weight of the second inorganic oxide. In yet another embodiment, Sn may be incorporated into the second catalytic region as a simple physical mixture (e.g., a physical blend). For example, Sn may be incorporated as SnO2 so as to be physically blended with the second OSC material and / or the second inorganic oxide, and the second catalyst region may contain up to 5 wt% Sn, preferably up to 4 wt% Sn, more preferably up to 3 wt% Sn, and even more preferably up to 2 wt% Sn, based on the total weight of the second catalyst region. Alternatively, the second catalyst region may contain 0.1 to 5 wt% Sn, preferably 0.2 to 4 wt% Sn, more preferably 0.3 to 3 wt% Sn, and even more preferably 0.4 to 1.5 wt% Sn, based on the total weight of the second catalyst region.In other embodiments, Sn may be incorporated into a second OSC material framework (for example, Sn may be doped into the crystal lattice of the formed OSC solid solution material), and the second OSC material framework may contain up to 5 wt% of Sn, preferably up to 4 wt% of Sn, more preferably up to 3 wt% of Sn, and even more preferably up to 2 wt% of Sn, based on the total weight of the second OSC material. Alternatively, the second OSC material may contain 0.1 to 5 wt% of Sn, preferably 0.1 to 4 wt% of Sn, more preferably 0.1 to 3 wt% of Sn, and even more preferably 0.1 to 2.5 wt% of Sn, based on the total weight of the second OSC material.

[0060] In some embodiments, the second catalyst region may contain up to 4 wt% of Sn, preferably up to 3 wt% of Sn, more preferably up to 2 wt% of Sn, and most preferably up to 1.5 wt% or 1 wt% of Sn, based on the total weight of the second catalyst region. Alternatively, the second catalyst region may contain 0.1 to 5 wt% of Sn, preferably 0.2 to 4 wt% of Sn, more preferably 0.3 to 3 wt% of Sn, and even more preferably 0.4 to 1.5 wt% of Sn, based on the total weight of the second catalyst region.

[0061] The second catalyst region can extend over 100 percent of the axial length L (see, for example, Figures 2a, 2b, and 6a-6c).

[0062] The second catalyst region can extend over 30 to 70 percent of the axial length L. Preferably, it can extend over 40 to 60 percent of the axial length L, more preferably over 45 to 55 percent, and most preferably, the total length of the second and first regions is greater than or equal to the axial length L (see, for example, Figures 3a to 5d and Figures 7a to 7l).

[0063] The second catalyst region may overlap with the first catalyst region by 0.1 to 99 percent of the axial length L (see, for example, Figures 3c and 3d; the first catalyst region may cover the second catalyst region, or the second catalyst region may cover the first catalyst region). Alternatively, the total length of the second and first catalyst regions may be equal to the axial length L (see, for example, Figures 3a and 3b). In yet another alternative, the total length of the second and first catalyst regions may be less than the axial length L, for example, 95%, 90%, 80%, or 70% or less of the axial length L.

[0064] In some embodiments, the first catalyst region may be directly supported / deposited on the substrate. In certain embodiments, the second catalyst region may be directly supported / deposited on the substrate.

[0065] Third catalytic region The catalyst article may further include a third catalyst region.

[0066] The third catalyst region may further include a third PGM component, a third oxygen storage (OSC) material, a third alkali or alkaline earth metal component, and / or a third inorganic oxide.

[0067] The third PGM component can be selected from the group consisting of platinum, palladium, rhodium, and mixtures thereof. In some embodiments, the third PGM component may be Pd, Rh, or mixtures thereof.

[0068] The third OSC material may be cerium oxide, zirconium oxide, ceria-zirconia mixed oxide, alumina-ceria-zirconia mixed oxide, or a combination thereof. More preferably, the third OSC material includes ceria-zirconia mixed oxide, alumina-ceria-zirconia mixed oxide, or a combination thereof. In addition, the third OSC material may further include one or more dopants such as lanthanum, neodymium, praseodymium, and yttrium. Furthermore, the third OSC material may function as a carrier material for the third PGM component. In some embodiments, the third OSC material includes ceria-zirconia mixed oxide and alumina-ceria-zirconia mixed oxide.

[0069] The ceria-zirconia mixed oxide can have a zirconia-to-ceria weight ratio of at least 50:50, preferably greater than 60:40, and more preferably greater than 75:25. Alternatively, the ceria-zirconia mixed oxide can also have a ceria-to-zirconia weight ratio of less than 50:50, preferably less than 40:60, and more preferably less than 25:75.

[0070] The third OSC material (e.g., ceria-zirconia mixed oxide) may be present in an amount of 10-90% by weight, preferably 25-75% by weight, and more preferably 30-60% by weight, based on the total washcoat load on the third catalyst region.

[0071] The amount of the third OSC material supported in the third catalytic region is 1.5 g / in. 3 It may be less than 1.2 g / in. In some embodiments, the amount of third OSC material supported in the second catalyst region is 1.2 g / in. 3 , 1.0g / in 3 , 0.9g / in 3 , 0.8g / in 3 , or 0.7g / in 3 The following applies:

[0072] The total wash coat load in the third catalyst region is 3.5 g / in. 3 Less than 3.0 g / in3 2.5g / in 3 , or 2g / in 3 It is possible.

[0073] The third alkali or alkaline earth metal is preferably barium, strontium, or a mixture or composite oxide thereof. Preferably, if present, the amount of barium or strontium is 0.1 to 15% by weight, more preferably 3 to 10% by weight, based on the total weight of the third catalyst region.

[0074] The third alkali or alkaline earth metal is more preferably strontium. If present, strontium is preferably present in an amount of 0.1 to 15% by weight, more preferably 3 to 10% by weight, based on the total weight of the third catalyst region.

[0075] Furthermore, the third alkali or alkaline earth metal is preferably a mixed oxide or composite oxide of barium and strontium. Preferably, the mixed oxide or composite oxide of barium and strontium is present in an amount of 0.1 to 15% by weight, more preferably 3 to 10% by weight, based on the total weight of the third catalyst region. The third alkali or alkaline earth metal is more preferably a composite oxide of barium and strontium.

[0076] Preferably, barium or strontium exists as BaCO3 or SrCO3. Such materials can be produced by any method known in the art, for example, by initial wetting impregnation or spray drying.

[0077] The third inorganic oxide is preferably an oxide of an element from Group 2, Group 3, Group 4, Group 5, Group 13, and Group 14. The third inorganic oxide is preferably selected from the group consisting of alumina, magnesia, silica, zirconia, barium oxide, and mixed or composite oxides thereof. Particularly preferred are alumina, lanthanum-alumina, zirconia, or magnesia / alumina composite oxides. One particularly preferred third inorganic oxide is alumina or lanthanum-alumina.

[0078] The third OSC material and the third inorganic oxide can have a weight ratio of 10:1 or less, preferably 8:1 or 5:1 or less, more preferably 4:1 or 3:1 or less, and most preferably 2:1 or less.

[0079] Alternatively, the third OSC material and the third inorganic oxide can have a weight ratio of 10:1 to 1:10, preferably 8:1 to 1:8 or 5:1 to 1:5, more preferably 4:1 to 1:4 or 3:1 to 1:3, and most preferably 2:1 to 1:2.

[0080] In some embodiments, the third OSC material and the third inorganic oxide may have a weight ratio of 2:1 or higher. In further embodiments, the third OSC material and the third inorganic oxide may have a weight ratio of 10:1 or higher. In yet another further embodiment, the third OSC material and the third inorganic oxide may have a weight ratio of 20:1 or higher or 30:1 or higher. In yet another further embodiment, the third OSC material and the third inorganic oxide may have a weight ratio of 40:1 or higher or 50:1 or higher.

[0081] In some embodiments, the third catalyst region may contain up to 5% by weight of Sn.

[0082] Tin (Sn) can be incorporated into the third catalytic region in various ways. In some embodiments, Sn can be incorporated into the third OSC material as a dopant, and the third OSC material may contain up to 5 wt% of Sn, preferably up to 4 wt% of Sn, more preferably up to 3 wt% of Sn, and even more preferably up to 2 wt% of Sn, based on the total weight of the third OSC material. Alternatively, the third OSC material may contain 0.1 to 5 wt% of Sn, preferably 0.2 to 4 wt% of Sn, more preferably 0.3 to 3 wt% of Sn, and even more preferably 0.4 to 2 wt% of Sn, based on the total weight of the third OSC material. In other embodiments, Sn may be incorporated into the third inorganic oxide as a dopant, the third inorganic oxide may contain up to 5 wt% Sn, preferably up to 4 wt% Sn, more preferably up to 3 wt% Sn, and even more preferably up to 2 wt% Sn, based on the total weight of the third inorganic oxide. Alternatively, the third inorganic oxide may contain 0.1 to 5 wt% Sn, preferably 0.2 to 4 wt% Sn, more preferably 0.3 to 3 wt% Sn, and even more preferably 0.4 to 2 wt% Sn, based on the total weight of the third inorganic oxide. In yet another embodiment, Sn may be incorporated into the third catalytic region as a simple physical mixture (e.g., a physical blend). For example, Sn may be incorporated as SnO2 so as to be physically blended with a third OSC material and / or a third inorganic oxide, and the third catalyst region may contain up to 5 wt% Sn, preferably up to 4 wt% Sn, more preferably up to 3 wt% Sn, and even more preferably up to 2 wt% Sn, based on the total weight of the third catalyst region. Alternatively, the third catalyst region may contain 0.1 to 5 wt% Sn, preferably 0.2 to 4 wt% Sn, more preferably 0.3 to 3 wt% Sn, and even more preferably 0.4 to 1.5 wt% Sn, based on the total weight of the third catalyst region. In other embodiments, Sn may be incorporated into a third OSC material framework (for example, Sn may be doped into the crystal lattice of the formed OSC solid solution material), the third OSC material framework may contain up to 5 wt% of Sn, preferably up to 4 wt% of Sn, more preferably up to 3 wt% of Sn, and even more preferably up to 2 wt% of Sn.Alternatively, the third OSC material may contain 0.1 to 5% by weight of Sn, preferably 0.1 to 4% by weight of Sn, more preferably 0.1 to 3% by weight of Sn, and even more preferably 0.1 to 2.5% by weight of Sn, based on the total weight of the third OSC material.

[0083] In some embodiments, the third catalyst region may contain up to 5 wt% of Sn, preferably up to 3 wt% of Sn, more preferably up to 2 wt% of Sn or up to 1 wt% of Sn, based on the total weight of the third catalyst region. Alternatively, the third catalyst region may contain 0.1 to 5 wt% of Sn, preferably 0.2 to 4 wt% of Sn, more preferably 0.3 to 3 wt% of Sn, and even more preferably 0.4 to 1.5 wt% of Sn, based on the total weight of the third catalyst region.

[0084] The third catalyst region can extend over 100 percent of the axial length L (see, for example, Figures 4a-4d and 6a-6c).

[0085] The third catalytic region may have an axial length less than L, for example, 95%, 90%, 80%, or 70% or less of the axial length L (see, for example, Figures 5a-5d and 7g-7l).

[0086] The second catalyst region may overlap with the first catalyst region by 0.1 to 99 percent of the axial length L (see, for example, Figures 7a to 7l), the first catalyst region may be stacked on the second catalyst region, or the second catalyst region may be stacked on the first catalyst region. Alternatively, either the second or first region may extend by 30 to 70 percent of the axial length L. Preferably, it may extend by 40 to 60 percent of the axial length L, more preferably by 45 to 55 percent, and most preferably, the total length of the second and first regions is less than or equal to the axial length L (see, for example, Figures 4a to 4d).

[0087] Fourth catalytic region The catalyst article may further include a fourth catalyst region.

[0088] The fourth catalyst region may further include a fourth PGM component, a fourth oxygen storage (OSC) material, a fourth alkali or alkaline earth metal component, and / or a fourth inorganic oxide.

[0089] The fourth PGM component can be selected from the group consisting of platinum, palladium, rhodium, and mixtures thereof. In some embodiments, the fourth PGM component may be Pd, Rh, or a mixture thereof.

[0090] The fourth catalyst region may have the same or similar composition as the third catalyst region.

[0091] The fourth catalyst region may have an axial length less than L, for example, 95%, 90%, 80%, or 70% or less of the axial length L.

[0092] Alternatively, either the fourth or third catalyst region can extend over 30 to 70 percent of the axial length L. Preferably, it can extend over 40 to 60 percent of the axial length L, more preferably over 45 to 55 percent, and most preferably, the total length of the fourth and third catalyst regions is greater than or equal to the axial length L (see, for example, Figures 5a to 5d).

[0093] The catalyst article of the present invention may further contain components known to those skilled in the art. For example, the composition of the present invention may further contain at least one binder and / or at least one surfactant. If a binder is present, a dispersible alumina binder is preferred.

[0094] Base material Preferably, the substrate is a flow-through monolith. Alternatively, the substrate may be a wall-flow filter.

[0095] The flow-through monolith substrate has a first surface and a second surface, with a longitudinal direction defined between them. The flow-through monolith substrate has a plurality of channels extending between the first surface and the second surface. The plurality of channels extend in the longitudinal direction and provide a plurality of inner surfaces (e.g., the surface of the wall defining each channel). Each of the plurality of channels has an opening on the first surface and an opening on the second surface. To avoid misunderstanding, the flow-through monolith substrate is not a wall flow filter.

[0096] The first surface is typically located at the inlet end of the substrate, and the second surface is located at the outlet end of the substrate.

[0097] The channels may have a fixed width, and each of the multiple channels may have a uniform channel width.

[0098] Preferably, in a plane perpendicular to the longitudinal direction, the monolithic substrate has 300 to 900 channels per square inch, preferably 400 to 800 channels. For example, on a first surface, the density of open first channels and closed second channels is 600 to 700 channels per square inch. The channels may have cross-sections that are rectangular, square, circular, elliptical, triangular, hexagonal, or other polygonal shapes.

[0099] The monolithic substrate acts as a carrier for holding the catalyst material. Suitable materials for forming the monolithic substrate include ceramic-like materials such as cordierite, silicon carbide, silicon nitride, zirconia, mullite, spodumene, alumina-silica-magnesia, or zirconium silicate, or porous refractory metals. Such materials and their use in the manufacture of porous monolithic substrates are well known in the art.

[0100] It should be noted that the flow-through monolith substrates described herein are single components (i.e., a single brick-like mass). Nevertheless, when forming an exhaust treatment system, the substrates used may be formed by bonding multiple channels together, or by bonding multiple smaller substrates together, as described herein. Such techniques, along with suitable casings and configurations for exhaust treatment systems, are known in the art.

[0101] In embodiments of the present invention in which the catalyst article includes a ceramic substrate, the ceramic substrate may be made of any suitable refractory material, such as alumina, silica, ceria, zirconia, magnesia, zeolite, silicon nitride, silicon carbide, zirconium silicate, magnesium silicate, aluminosilicate and metalloaluminosilicate (such as cordierite and spodumene), or a mixture or mixed oxide of two or more of these. Cordierite, magnesium aluminosilicate, and silicon carbide are particularly preferred.

[0102] In embodiments of the present invention in which the catalyst article includes a metal substrate, the metal substrate may be made of any suitable metal, particularly heat-resistant metals and metal alloys such as titanium and stainless steel, as well as ferrite alloys containing iron, nickel, chromium, and / or aluminum in addition to other trace metals.

[0103] Another aspect of this disclosure is the use of the catalyst articles described herein, NO x This invention relates to a method for treating vehicle exhaust gases containing CO and HC. A catalytic converter equipped with a TWC fabricated according to this method exhibits improved catalytic properties compared to a conventional TWC (with the same PGM load), and also shows particularly improved performance in the cold start phase and better THC light-off performance (see, for example, Examples 2 to 4 and Examples 6 to 7, and Tables 3 to 5 and Tables 7 to 9).

[0104] Another aspect of this disclosure relates to a vehicle exhaust gas treatment system that includes a catalytic article described herein, along with conduits for transporting exhaust gases through the system.

[0105] definition As used herein, the term “region” typically refers to a location on a substrate obtained by drying and / or firing a wash coat. A “region” may be positioned or supported on the substrate as, for example, a “layer” or “zone.” The location or position on the substrate is generally controlled during the process of applying the wash coat to the substrate. A “region” typically has a clear boundary or border (i.e., it is possible to distinguish one region from another using conventional analytical techniques).

[0106] Typically, a “region” has a substantially uniform length. In this context, “substantially uniform length” means a length that does not deviate by more than 10% from its mean (e.g., the difference between the maximum and minimum lengths), preferably by more than 5%, and more preferably by more than 1%.

[0107] Each “region” preferably has a substantially uniform composition (i.e., there is no substantial difference in the composition of the wash coat when comparing one part of a region with another part of that region). In this context, a substantially uniform composition means a material (e.g., a region) in which, when comparing one part of a region with another part of that region, the difference in composition is 5% or less, usually 2.5% or less, and most commonly 1% or less.

[0108] As used herein, the term “zone” refers to an area having a length less than the total length of the substrate, such as a length of 75% or less of the total length of the substrate. A “zone” typically has a length of at least 5% (e.g., 5% or more) of the total length of the substrate (i.e., a substantially uniform length).

[0109] The total length of the substrate is the distance between its inlet end and its outlet end (for example, both ends of the substrate).

[0110] Any reference to “zone located at the inlet end of the substrate” as used herein refers to a zone located or supported on the substrate such that the inlet end of the substrate is closer than the outlet end of the substrate. Therefore, the midpoint of the zone (i.e., the point halfway along its length) is closer to the inlet end of the substrate than to the outlet end of the substrate. Similarly, any reference to “zone located at the outlet end of the substrate” as used herein refers to a zone located or supported on the substrate such that the outlet end of the substrate is closer than the inlet end of the substrate. Therefore, the midpoint of the zone (i.e., the point halfway along its length) is closer to the outlet end of the substrate than to the inlet end of the substrate.

[0111] When the substrate is a wall flow filter, any reference to “the zone located at the inlet end of the substrate” generally refers to a zone located or supported on the substrate. (a) Zones and / or zones where the inlet end (e.g., open end) of the substrate inlet channel is closer than the closed end (e.g., blocked or sealed end) of the inlet channel. (b) A zone in which the closed end of the outlet channel of the substrate (e.g., a blocked or sealed end) is closer than the outlet end of the outlet channel (e.g., an open end).

[0112] Therefore, the midpoint of the zone (i.e., the point at half its length) is (a) closer to the inlet end of the substrate inlet channel than to the closed end of the inlet channel, and / or (b) closer to the closed end of the substrate outlet channel than to the outlet end of the outlet channel.

[0113] Similarly, if the substrate is a wall flow filter, any reference to “the zone located at the outlet end of the substrate” is a zone located on or supported on the substrate, (a) Zones and / or zones where the exit end (e.g., open end) of the exit channel of the substrate is closer than the closed end (e.g., blocked or sealed end) of the exit channel. (b) A zone in which the closed end of the substrate's inlet channel (e.g., a blocked or sealed end) is closer than the inlet end of the inlet channel (e.g., an open end).

[0114] Therefore, the midpoint of the zone (i.e., the point at half its length) is (a) closer to the exit end of the substrate's exit channel than to the closed end of the exit channel, and / or (b) closer to the closed end of the substrate's inlet channel than to the inlet end of the inlet channel.

[0115] If the washcoat is present on the wall of the wall flow filter (i.e., the zone is within the wall), then the zone may satisfy both (a) and (b).

[0116] The term "wash coat" is well known in the art and typically refers to an adhesive coating applied to a substrate during the production of a catalyst.

[0117] As used herein, the acronym "PGM" refers to "platinum group metals." The term "platinum group metals" generally refers to metals selected from the group consisting of Ru, Rh, Pd, Os, Ir, and Pt, preferably metals selected from the group consisting of Ru, Rh, Pd, Ir, and Pt. Generally, the term "PGM" preferably refers to metals selected from the group consisting of Rh, Pt, and Pd.

[0118] As used herein, the term “mixed oxide” generally refers to a mixture of oxides in single phases, as is conventionally known in the art. As used herein, the term “composite oxide” generally refers to a composition of oxides having two or more phases, as is conventionally known in the art.

[0119] Where used herein, the expression “essentially consists of” limits the scope of a feature to include a specific material or process, and any other material or process that includes, for example, trace impurities and does not substantially affect the fundamental properties of the feature. The expression “essentially consists of” includes the expression “consists of.”

[0120] When used herein with respect to materials, the expression “substantially absent” typically means that the material is present in small amounts, for example, 5% by weight or less, preferably 2% by weight or less, and more preferably 1% by weight or less, in relation to the contents of an area, layer, or zone. The expression “substantially absent” encompasses the expression “absent.”

[0121] When used herein with respect to materials, the expression “essentially not present” typically means that the material is present in trace amounts, for example, 1% by weight or less, preferably 0.5% by weight or less, and more preferably 0.1% by weight or less, in relation to the contents of an area, layer, or zone. The expression “essentially not present” encompasses the expression “not present.”

[0122] Where used herein, any reference to the amount of dopant expressed as a weight percent, in particular to the total amount, refers to the weight of the carrier material or its refractory metal oxide.

[0123] As used herein, the term "loading capacity" refers to g / ft based on the weight of the metal. 3 It refers to the measured value in that unit.

[0124] The following examples are merely illustrative of the present invention. Those skilled in the art will recognize many variations within the spirit and claims of the present invention. [Examples]

[0125] Example 1 - Improvement of OSC performance by Sn doping OSC1-6 Six OSC materials: OSC1-6 in Table 1 were prepared by impregnating a soluble Sn solution onto a Ce / Zr mixed oxide material stabilized with rare earth oxides, and then calcining it at 500°C.

[0126] The OSC performance of Sn-doped Ce / Zr mixed oxide materials was determined by measuring the weight loss of the material under H2 reduction conditions, resulting from oxygen release, using thermogravimetric analysis. The amount of oxygen molecules released (moles) was calculated by the weight loss at lower temperatures of 200°C and higher temperatures of 600°C after redox aging at 1000°C for 4 hours. Significant improvements in OSC performance were obtained in the range of 0.1% to 1.5% Sn content.

[0127] [Table 1]

[0128] Example 2 - Improvement of catalyst performance Comparative catalyst 1 Comparative catalyst 1 is a coated catalyst on a cordierite substrate, consisting of 3 wt% Pd and 5 wt% Ba, as shown in Table 1, supported on a mixture of La-stabilized alumina and OSC1, with a total wash coat load of 2.0 g / in 3 That is the case.

[0129] Catalyst 2 Catalyst 2 is a coated catalyst on a cordierite substrate, consisting of 3 wt% Pd as shown in Table 1, supported on a mixture of La-stabilized alumina and OSC5, with a Sn load of 0.8 wt% based on the total weight of the catalyst 2 composition, and a total wash coat load of 2.0 g / in 3 That is the case.

[0130] Catalyst performance tests were conducted on comparative catalyst 1 and comparative catalyst 2 using simulated exhaust gases having the compositions shown in Table 2, under the following conditions.

[0131] In catalyst performance tests, the temperature at which 50% of each of the HC and CO components are converted is defined as T 50 It was evaluated as follows: The fact that 50% of the conversion temperature is lower means that the performance as an exhaust gas purification catalyst is better.

[0132] In the catalyst performance test, the gas flow rate was set to a space velocity of 100,000 / hour, and the temperature was increased from 100°C to 400°C at a heating rate of 25°C / min. The gas composition after passing through the catalyst was analyzed, and the conversion rate was measured.

[0133] [Table 2]

[0134] [Table 3]

[0135] As shown in Table 3 above, the temperature at which 50% of the conversion to HC and CO occurs is 13°C and 22°C lower for catalyst 2 compared to comparative catalyst 1.

[0136] Example 3: Light-off performance and OSC test in synthetic catalyst activity testing Comparison catalyst A: First catalytic region: The first catalyst region consists of a CeZr mixed oxide, an alumina-ceria-zirconia mixed oxide, La-stabilized alumina, and Pt supported on a wash coat of a Ba promoter. The amount of wash coat support for the first catalyst region is approximately 1.8 g / in. 3 The Pt load is 42g / ft 3 That was the case.

[0137] Next, using a standard coating procedure, the wash coat was applied from the entrance surface of the ceramic substrate to a target coating depth of 80% of the substrate's length (600 cpsi, wall thickness 4.3 mm), and then dried at 100°C.

[0138] Second catalytic region: The second catalyst region consists of Rh supported on a wash coat of CeZr mixed oxide and La-stabilized alumina. The amount of Rh supported on the wash coat of the second catalyst region is approximately 1.3 g / in. 3 The Rh load is 8g / ft 3 That was the case.

[0139] Next, using a standard coating procedure, the second wash coat was applied from the exit surface of the ceramic substrate containing the first catalyst region to a target coating depth of 80% of the substrate's length, dried at 100°C, and fired at 500°C for 45 minutes.

[0140] Catalyst B: Catalyst B is prepared in the same procedure as comparative catalyst A, except that in the first catalytic region, 2% by weight of Sn is supported on an alumina-ceria-zirconia mixed oxide with a Sn loading amount of 0.7% by weight based on the total weight of the first catalytic region.

[0141] Catalyst B and comparative catalyst A were tested separately using a Synthetic Catalyst Activity Test (SCAT) device. Light-off performance was tested with a gas flow of 10 vol% H2O + 14 vol% CO2 + 333 ppm C3H6 + 167 ppm C3H8 + 1.5 vol% CO + 0.5 vol% H2O + 1.15 vol% O2 + 1000 ppm NO (balanced by N2) (space velocity 60,000 h) -1 The temperature gradient is 30°C / min. THC, CO, and NO x The conversion was calculated by comparing the concentration of the supply gas with the concentration of the gas at the catalyst outlet. OSC was calculated in a gas flow of 10 vol% H2O + 14 vol% CO2 + 333 ppm C3H6 + 167 ppm C3H8 + 0.5 vol% CO + 0.5 vol% H2O + 0.5 vol% O2 + 1000 ppm NO (balanced by N2) (space velocity 60000 h) -1The tests were conducted at 450°C. Comparative catalysts A and B were hydrothermally aged at 1050°C for 6 hours with a flow rate of 5 L / min of 2 vol% O2 + 10 vol% H2O (balanced by N2).

[0142] Unused and aged catalyst B and comparative catalyst A: HC, CO, and NO x T 50 The light-off temperature and OSC are shown in Table 4. Surprisingly, the data shows that the unused catalyst B of the present invention produced CO, HC, and NO compared to comparative catalyst A. x Regarding these, the temperature is approximately 17°C, 10.5°C, and 6°C lower, respectively. 50 (T 50 This indicates a significantly improved light-off performance, as shown by the temperature at which the conversion rate reaches 50%. On the other hand, the OSC of catalyst B is higher than that of comparative catalyst A, both in its unused and aged state.

[0143] [Table 4]

[0144] Example 4: Light-off performance test in synthetic catalyst activity testing Comparison catalyst C: First catalytic region: The first catalyst region consists of a wash coat of CeZr mixed oxide, alumina-ceria-zirconia mixed oxide, and Pt supported on a wash coat of La-stabilized alumina. The amount of wash coat supported on the first catalyst region is approximately 2.0 g / in. 3 The Pt load is 74g / ft 3 That was the case.

[0145] Next, using a standard coating procedure, the wash coat was applied from the entrance surface of the ceramic substrate to a target coating depth of 50% of the substrate's length (600 cpsi, wall thickness 2.5 mm), and then dried at 100°C.

[0146] Second catalytic region: The second catalytic region consists of a wash coat of CeZr mixed oxide, alumina-ceria-zirconia mixed oxide, and Pt supported on a wash coat of La-stabilized alumina. The amount of wash coat supported on the second catalytic region is approximately 2.0 g / in. 3 The Pt load is 24g / ft 3 That was the case.

[0147] Next, using a standard coating procedure, the second wash coat was applied from the exit surface of the ceramic substrate containing the first catalyst region to a target coating depth of 50% of the substrate length, dried at 100°C, and fired at 500°C for 45 minutes.

[0148] The third catalytic region: The third catalytic region consists of Rh supported on a wash coat of CeZr mixed oxide and La-stabilized alumina. The amount of Rh supported on the wash coat of the third catalytic region is approximately 1.5 g / in. 3 The Rh load is 6g / ft 3 That was the case.

[0149] Next, using a standard coating procedure, a third wash coat was applied from the exit surface of the ceramic substrate containing the first and second catalyst regions, with a target coating depth of 100% of the substrate length. The substrate was then dried at 100°C and fired at 500°C for 45 minutes.

[0150] Catalyst D: Catalyst D is prepared in the same procedure as comparative catalyst C, except that in the first and second catalytic regions, 2% by weight of Sn is supported on an alumina-ceria-zirconia mixed oxide with a Sn loading amount of 0.75% by weight based on the weight of either the first or second catalytic region.

[0151] Catalyst D and comparative catalyst C were tested separately using a synthetic catalyst activity test (SCAT) device. Light-off performance was tested in a gas flow of 10 vol% H2O + 14 vol% CO2 + 333 ppm C3H6 + 167 ppm C3H8 + 1.5 vol% CO + 0.5 vol% H2O + 1.15 vol% O2 + 1000 ppm NO (balanced by N2) (space velocity 60,000 h) -1 The temperature gradient was 30°C / min. THC, CO, and NO x The conversion was calculated by comparing the concentration of the supply gas with the concentration of the gas at the catalyst outlet. Catalyst D and comparative catalyst C were hydrothermally aged at 1050°C for 6 hours with a flow rate of 5 L / min of 2 vol% O2 + 10 vol% H2O (balanced by N2).

[0152] Unused and aged catalyst D and comparative catalyst C: HC, CO, and NO x T 50 The light-off temperatures are shown in Table 5. The data show that catalyst D of the present invention exhibits significantly improved light-off performance compared to comparative catalyst C, both in unused and aged states. CO, HC, and NO of catalyst D x T 50 The temperature decreased by 17.5°C, 11°C, and 9°C respectively when unused, and when aged at 19°C, 16.5°C, and 14.5°C.

[0153] [Table 5]

[0154] Example 5: Characterization of Pt dispersion Comparison catalyst E: First catalytic region: The first catalyst region consists of a wash coat of CeZr mixed oxide, alumina-ceria-zirconia mixed oxide, and Pt supported on a wash coat of La-stabilized alumina. The amount of wash coat supported on the first catalyst region is approximately 2.0 g / in. 3 The Pt load is 74g / ft 3 That was the case.

[0155] Next, using a standard coating procedure, the wash coat was applied from the exit surface of the ceramic substrate to a target coating depth of 100% of the substrate length (600 cpsi, wall thickness 2.5 mm), dried at 100°C, and fired at 500°C for 45 minutes.

[0156] Catalyst F: Catalyst F was prepared in the same procedure as comparative catalyst E, except that in the first catalytic region, 2% by weight of Sn was supported on an alumina-ceria-zirconia mixed oxide with a Sn loading amount of 0.75% by weight based on the weight of the first catalytic region.

[0157] The Pt dispersion of catalyst F and comparative catalyst E was tested separately by CO pulse chemiadsorption measurement at 50°C. The catalysts were pre-treated with H2 gas at 300°C for 10 minutes prior to the CO pulse test. The dispersion was estimated using a 1:1 CO:Pt ratio. Prior to the CO pulse chemiadsorption test, catalyst F and comparative catalyst E were hydrothermally aged at 1050°C for 6 hours with a flow rate of 5 L / min of 2 vol% O2 + 10 vol% H2O (balanced by N2). The results of the Pt dispersion test are shown in Table 6. The data indicates that catalyst F has approximately 6 times the Pt dispersion of comparative catalyst E after hydrothermal aging.

[0158] [Table 6]

[0159] Example 6: Procedure and results of vehicle testing Comparative catalyst G: First catalytic region: The first catalyst region consists of a wash coat of CeZr mixed oxide, alumina-ceria-zirconia mixed oxide, and Pt supported on a wash coat of La-stabilized alumina. The amount of wash coat supported on the first catalyst region is approximately 2.5 g / in. 3 The Pt load is 74g / ft 3 That was the case.

[0160] Next, using a standard coating procedure, the wash coat was applied from the entrance surface of the ceramic substrate to a target coating depth of 50% of the substrate's length (600 cpsi, wall thickness 2.5 mm), and then dried at 100°C.

[0161] Second catalytic region: The second catalytic region consists of a wash coat of CeZr mixed oxide, alumina-ceria-zirconia mixed oxide, and Pt supported on a wash coat of La-stabilized alumina. The amount of wash coat supported on the second catalytic region is approximately 2.5 g / in. 3 The Pt load is 24g / ft 3 That was the case.

[0162] Next, using a standard coating procedure, the second wash coat was applied from the exit surface of the ceramic substrate containing the first catalyst region to a target coating depth of 50% of the substrate length, dried at 100°C, and fired at 500°C for 45 minutes.

[0163] The third catalytic region: The third catalytic region consists of Rh supported on a wash coat of CeZr mixed oxide and La-stabilized alumina. The amount of Rh supported on the wash coat of the third catalytic region is approximately 1.5 g / in. 3 The Rh load is 6g / ft 3 That was the case.

[0164] Next, using a standard coating procedure, a third wash coat was applied from the exit surface of the ceramic substrate containing the first and second catalyst regions, with a target coating depth of 100% of the substrate length. The substrate was then dried at 100°C and fired at 500°C for 45 minutes.

[0165] Catalyst H: Catalyst H is prepared in the same procedure as comparative catalyst G, except that in the first and second catalytic regions, 2% by weight of Sn is supported on an alumina-ceria-zirconia mixed oxide with a Sn load of 0.75% by weight based on the total weight of either the first or second catalytic region.

[0166] Bench-aged samples of catalyst G and comparative catalyst H were tested in a 1.5-liter engine vehicle using the Worldwide Harmonized Light Gas and Fuel Economy Test Procedure (WLTP). Bench-aging was performed in a 6.1-liter engine with a peak bed temperature of approximately 980°C, a 4-mode aging cycle, and the same 200-hour operation period. The results of the vehicle exhaust dilution bag data for the bench-aged components are shown in Table 7. Compared to comparative catalyst G, catalyst H of the present invention produced THC and NO x It shows excellent activity in controlling emissions (e.g., THC and NO). x The performance of these components improved by approximately 27% and 46%, respectively.

[0167] [Table 7]

[0168] Example 7: Procedure and results of vehicle testing Bench-aged samples of catalyst G and comparative catalyst H were tested in a 1.5-liter engine vehicle using the Worldwide Light Duty Testing Procedure (WLTP). Bench-aging was performed in a 6.1-liter engine with a catalyst peak bed temperature of approximately 980°C, using a 4-mode aging cycle, and the same 200-hour operation period. The results of the vehicle exhaust dilution bag data for the bench-aged components are shown in Table 8. Compared to comparative catalyst G, catalyst H of the present invention produced THC, CO, and NO emissions. x It showed excellent activity in controlling emissions of (e.g., THC, CO, and NO). x The performance of each component improved by approximately 57%, 20%, and 64%, respectively.

[0169] [Table 8]

[0170] Example 8: Light-off performance test in engine testing Comparative catalyst I: First catalytic region: The first catalyst region consists of Pt supported on a wash coat of CeZr mixed oxide and La-stabilized alumina. The amount of Pt supported on the wash coat of the first catalyst region is approximately 2.3 g / in. 3 The Pt load is 49 g / ft 3 That was the case.

[0171] Next, using a standard coating procedure, the wash coat was applied from the exit surface of the ceramic substrate to a target coating depth of 100% of the substrate length (600 cpsi, wall thickness 2.5 mm), dried at 100°C, and fired at 500°C for 45 minutes.

[0172] Catalyst J: Catalyst J was prepared in the same procedure as comparative catalyst I, except that in the first catalyst region, SnO2 powder was added directly to the washcoat by physical blending, with a Sn loading amount of approximately 1% by weight based on the total weight of the first catalyst region.

[0173] Bench-aged catalysts J and comparative catalyst I were tested separately on a gasoline engine. Light-off performance was tested under typical conditions: exhaust gas flow rate of 80 kg / hour, temperature gradient of 30°C / min, and air-fuel ratio (AFR) lambda of 14.45. THC and CO conversion rates were calculated by comparing the concentrations of the supply gas and the gas at the catalyst outlet. Before the engine light-off test, catalysts H and comparative catalyst G were bench-aged for 200 hours. Bench-aging was performed on a 6.1L engine with a catalyst peak bed temperature of approximately 950°C, using a 4-mode aging cycle, and operating for the same 200 hours.

[0174] T of HC and CO in catalyst J and comparative catalyst I 10 (T 10 Table 9 shows the temperature at which the conversion rate reached 10%. The data shows that catalyst J showed significantly improved light-off performance for HC and CO compared to comparative catalyst I. 10 However, the temperature dropped by approximately 40°C.

[0175] [Table 9] Furthermore, it should be confirmed that the present invention, as described above, encompasses the following aspects. First aspect: A catalyst composition comprising a platinum group metal (PGM) component and a PGM support material, wherein the catalyst composition contains up to 5% by weight of Sn. Second aspect: The catalyst composition according to the first embodiment, wherein the PGM component is platinum, palladium, rhodium, or a combination thereof. Third aspect: The catalyst composition according to the first or second embodiment, wherein the PGM component is platinum. Fourth aspect: The catalyst composition according to the first or second embodiment, wherein the PGM component is platinum and rhodium; palladium and rhodium; or platinum, palladium, and rhodium. Fifth aspect: The catalyst composition according to any one of the first to fourth embodiments, wherein the PGM support material is an oxygen storage capacity (OSC) material, an inorganic oxide, or a combination thereof. Sixth aspect: The catalyst composition according to the fifth embodiment, wherein the OSC material comprises cerium oxide, ceria-zirconia mixed oxide, alumina-ceria-zirconia mixed oxide, or a combination thereof. Seventh aspect: The catalyst composition according to the fifth or sixth embodiment, wherein the inorganic oxide is selected from the group consisting of alumina, magnesia, silica, zirconia, lanthanum, neodymium, praseodymium, yttrium oxide, and mixed oxides or composite oxides thereof. Eighth aspect: A catalyst composition according to any one of the first to seventh embodiments, which is a three-way catalyst (TWC). Appearance 9: A catalytic article for treating exhaust gases, A base material including an inlet end and an outlet end having an axial length L, A catalyst article comprising: a first catalyst region comprising a first platinum group metal (PGM) component and a first PGM support material, the first catalyst region comprising up to 5% by weight of Sn. Tenth aspect: The catalyst article according to the ninth embodiment, wherein the first PGM component is platinum, palladium, rhodium, or a combination thereof. Appearance 11: The catalyst article according to the ninth or tenth embodiment, wherein the first PGM component is platinum. Appearance 12: The catalyst article according to the ninth or tenth embodiment, wherein the first PGM component is platinum and rhodium; palladium and rhodium; or platinum, palladium, and rhodium. Appearance 13: The catalyst article according to any one of the first to twelfth embodiments, wherein the first PGM support material is a first oxygen storage capacity (OSC) material, a first inorganic oxide, or a combination thereof. Appearance 14: The catalyst article according to the 13th embodiment, wherein the first OSC material is cerium oxide, a ceria-zirconia mixed oxide, an alumina-ceria-zirconia mixed oxide, or a combination thereof. Appearance 15: The catalyst article according to the 13th or 14th embodiment, wherein the first inorganic oxide is selected from the group consisting of alumina, magnesia, silica, zirconia, lanthanum, neodymium, praseodymium, yttrium oxide, and mixed oxides or composite oxides thereof. Appearance 16: A catalyst article according to any one of the 9th to 15th embodiments, which is a three-way catalyst (TWC). Appearance 17: A catalyst article according to any one of the 9th to 16th embodiments, further comprising a second catalyst region. Apparatus 18: The catalyst article according to the 17th embodiment, wherein the second catalyst region contains a second PGM component. Appearance 19: The catalyst article according to the 18th embodiment, wherein the second PGM component is selected from the group consisting of platinum, palladium, rhodium, and mixtures thereof. 20th aspect: The catalyst article according to any one of the 17th to 19th embodiments, wherein the second catalyst region further comprises a second OSC material. 21st aspect: The catalyst article according to the 20th embodiment, wherein the second OSC material is cerium oxide, zirconium oxide, ceria-zirconia mixed oxide, alumina-ceria-zirconia mixed oxide, or a combination thereof. 22nd aspect: A catalyst article according to any one of the 17th to 21th embodiments, further comprising a second inorganic oxide. 23rd aspect: The catalyst article according to the 22nd embodiment, wherein the second inorganic oxide is selected from the group consisting of alumina, magnesia, silica, zirconia, lanthanum, cerium, neodymium, praseodymium, yttrium oxide, and mixed oxides or composite oxides thereof. Appearance 24: The catalyst article according to any one of the 20th to 23rd embodiments, wherein the second catalyst region contains up to 5% by weight of Sn. 25th aspect: The catalyst article according to any one of the 9th to 24th embodiments, wherein the first catalyst region extends over the axial length L. 26th aspect: The catalyst article according to any one of the 17th to 25th embodiments, wherein the second catalyst region extends over the axial length L. Appearance 27: The catalyst article according to the 25th or 26th embodiment, wherein the first catalyst region is directly supported / deposited on the substrate. Apparatus 28: The catalyst article according to the 25th or 26th embodiment, wherein the second catalyst region is directly supported / deposited on the substrate. 29th aspect: The catalyst article according to any one of the 9th to 24th embodiments, wherein the first catalyst region extends over an axial length less than L. 30th aspect: The catalyst article according to any one of the 17th to 25th embodiments, wherein the second catalyst region extends over an axial length less than L. 31st aspect: The catalyst article according to the 29th or 30th embodiment, wherein the first catalyst region is directly supported / deposited on the substrate. 32nd aspect: The catalyst article according to the 29th or 30th embodiment, wherein the second catalyst region is directly supported / deposited on the substrate. 33rd aspect: A catalyst article according to any one of embodiments 9 to 32, further comprising a third catalyst region. Appearance 34: The catalyst article according to the 33rd embodiment, wherein the third catalyst region contains a third PGM component. Appearance 35: The catalyst article according to the 34th embodiment, wherein the third PGM component is selected from the group consisting of platinum, palladium, rhodium, and mixtures thereof. 36th aspect: The catalyst article according to any one of the 33rd to 35th embodiments, wherein the third catalyst region further comprises a third OSC material. Appearance 37: The catalyst article according to the 36th embodiment, wherein the third OSC material is cerium oxide, zirconium oxide, ceria-zirconia mixed oxide, alumina-ceria-zirconia mixed oxide, or a combination thereof. Apparatus No. 38: The catalyst article according to the 36th or 37th embodiment, wherein the third catalyst region contains up to 5% by weight of Sn. 39th aspect: A catalyst article according to any one of the 33rd to 38th embodiments, further comprising a third inorganic oxide. Forty-first aspect: The catalyst article according to the 39th embodiment, wherein the third inorganic oxide is selected from the group consisting of alumina, magnesia, silica, zirconia, lanthanum, cerium, neodymium, praseodymium, yttrium oxide, and mixed oxides or composite oxides thereof. 41st aspect: The catalyst article according to any one of the 33rd to 40th embodiments, wherein the third catalyst region extends over the axial length L. 42nd aspect: The catalyst article according to any one of the 33rd to 40th embodiments, wherein the third catalyst region extends over an axial length less than L.

Claims

1. A catalyst composition for treating gasoline engine exhaust gases, comprising platinum group metal (PGM) components and PGM support material, comprising up to 5% by weight of Sn, The PGM carrier material is an oxygen storage (OSC) material and an inorganic oxide. The OSC material is a catalyst composition which is a ceria-zirconia mixed oxide, an alumina-ceria-zirconia mixed oxide, or a combination thereof.

2. The catalyst composition according to claim 1, wherein the PGM component is platinum, palladium, rhodium, or a combination thereof.

3. The catalyst composition according to claim 1 or 2, wherein the inorganic oxide is selected from the group consisting of alumina, magnesia, silica, zirconia, lanthanum, neodymium, praseodymium, yttrium oxide, and mixed oxides or composite oxides thereof.

4. A catalytic article for treating gasoline engine exhaust gas, A base material including an inlet end and an outlet end having an axial length L, A first catalyst region comprising a first platinum group metal (PGM) component and a first PGM support material, the first catalyst region comprising up to 5% by weight of Sn, The first PGM carrier material is a first oxygen storage (OSC) material and a first inorganic oxide. The catalyst article wherein the first OSC material is a ceria-zirconia mixed oxide, an alumina-ceria-zirconia mixed oxide, or a combination thereof.

5. The catalyst article according to claim 4, wherein the first PGM component is platinum, palladium, rhodium, or a combination thereof.

6. The catalyst article according to claim 4 or 5, wherein the first inorganic oxide is selected from the group consisting of alumina, magnesia, silica, zirconia, lanthanum, neodymium, praseodymium, yttrium oxide, and mixed oxides or composite oxides thereof.

7. A catalyst article according to any one of claims 4 to 6, further comprising a second catalyst region.

8. The catalyst article according to any one of claims 4 to 7, wherein the first catalyst region extends over the axial length L.

9. The catalyst article according to claim 7 or 8, wherein the second catalyst region extends over the axial length L.

10. The catalyst article according to claim 8 or 9, wherein the first catalyst region is directly supported / deposited on the substrate.

11. The catalyst article according to claim 8 or 9, wherein the second catalyst region is directly supported / deposited on the substrate.

12. The catalyst article according to any one of claims 4 to 7, wherein the first catalyst region extends over an axial length less than L.

13. The catalyst article according to claim 7 or 8, wherein the second catalyst region extends over an axial length less than L.

14. The catalyst article according to claim 12 or 13, wherein the first catalyst region is directly supported / deposited on the substrate.

15. The catalyst article according to claim 12 or 13, wherein the second catalyst region is directly supported / deposited on the substrate.

16. A catalyst article according to any one of claims 4 to 15, further comprising a third catalyst region.

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