Highly dopant-containing supports containing improved TWC catalysts.

Abstract

To provide a catalyst article for treating exhaust gas, and a method for treating exhaust gas using the catalyst article.SOLUTION: The catalyst article for treating exhaust gas comprises: a substrate; a first catalytic region on the substrate; and a second catalytic region on the substrate. The first catalytic region comprises a first PGM component and a first inorganic oxide. The second catalytic region comprises a second PGM component and a second inorganic oxide. At least one of the first inorganic oxide and the second inorganic oxide is doped with 10-30% of dopants.SELECTED DRAWING: Figure 1a

Description

[Technical Field]

[0001] The present invention relates to catalytic articles useful for treating exhaust gas emissions from gasoline engines. [Background technology]

[0002] In an internal combustion engine, hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NO x The exhaust gas produced by the engine contains various pollutants, including CO, HC, and NO. Emissions control systems, including exhaust gas catalysts, are widely used to reduce the amount of these pollutants emitted into the atmosphere. The catalyst typically used in gasoline engine applications is the TWC. The TWC performs three main functions: (1) oxidation of CO, (2) oxidation of unburned HC, and (3) oxidation of NO. x is reduced to N2.

[0003] In most catalytic converters, platinum group metals (PGMs) (e.g., Pt, Pd, and Rh) are used as the active sites for catalytic conversion and have been widely used in combination with other inorganic compounds, such as alumina and ceria-zirconia mixed oxides, as supports. When the temperature of TWCs reaches approximately 1000°C, especially under high-load operation in gasoline-powered vehicles, the supports are usually stabilized with dopant elements. For example, the thermal durability of alumina materials is significantly improved by doping with lanthanum (La). Because the thermal stability of alumina materials reaches a maximum at around 1–2 wt% and remains almost unchanged up to 5 wt%, La is typically used in alumina TWCs at low La contents of less than 5 wt% (see, for example, Thévenin et al., Journal of Catalysis, 2002, 207, 139–149; Shinjoh, Journal of Alloys and Compounds, 2006, 408–412, 1061–1064). Such improved thermal stability of the support is useful for achieving high dispersion of PGM particles to produce TWCs with higher catalytic performance.

[0004] On the other hand, in the exhaust gas of a gasoline engine, the concentration of CO is higher than that of other harmful HC and NO x Because CO concentrations are significantly higher than those of other gases, PGMs are usually poisoned by high concentrations of CO, i.e., the PGM active sites are covered by strongly adsorbed CO, thereby deactivating catalytic performance. Countermeasures against PGM poisoning are another technical approach to maintain PGM active sites and promote catalytic conversion in the presence of high CO gas concentrations. The present invention addresses the need to reduce the effects of CO poisoning for improved TWC performance. Summary of the Invention

[0005] One aspect of the present disclosure relates to a catalyst composition comprising a platinum group metal (PGM) component and an inorganic oxide, wherein the PGM component has an infrared (IR) intensity ratio of bridge site CO to atop site CO of less than 3:1 under a reference CO adsorption procedure.

[0006] Another aspect of the present disclosure relates to a catalyst composition comprising a platinum group metal (PGM) component and an inorganic oxide, wherein the PGM component has an infrared (IR) intensity ratio of CO at gem-dicarbonyl sites to CO at atop sites that is less than 5:1 under a reference CO adsorption procedure.

[0007] Another aspect of the present disclosure relates to a catalytic article for treating exhaust gases, the catalytic article comprising: a substrate; and a first catalytic region on the substrate, the first catalytic region comprising a first PGM component and a first inorganic oxide, wherein the PGM component has an IR intensity ratio of bridge site CO to atop site CO of less than 3:1 under a reference CO adsorption procedure.

[0008] Another aspect of the present disclosure relates to a catalytic article for treating exhaust gases, the catalytic article comprising: a substrate; and a first catalytic region on the substrate, the first catalytic region comprising a first PGM component and a first inorganic oxide, wherein the PGM component has an IR intensity ratio of CO at gem-dicarbonyl sites to CO at atop sites that is less than 5:1 under a reference CO adsorption procedure.

[0009] Another aspect of the present disclosure relates to a catalytic article for treating exhaust gases, the catalytic article comprising: a substrate; a first catalytic region on the substrate; and a second catalytic region on the substrate, wherein the first catalytic region comprises a first PGM component and a first inorganic oxide; the second catalytic region comprises a second PGM component and a second inorganic oxide; and at least one of the first inorganic oxide and the second inorganic oxide is doped with 10-30% dopant.

[0010] The present invention also includes an exhaust system for an internal combustion engine that includes the three-way catalyst component of the present invention.

[0011] The present invention also encompasses the treatment of exhaust gases from internal combustion engines, particularly gasoline engines, which method comprises contacting the exhaust gases with a three-way catalyst component or article of the present invention. [Brief explanation of the drawings]

[0012] [Figure 1a] IR intensity ratio of CO at the bridge site to CO at the atop site for Pd / La-alumina catalysts with different La loadings. [Figure 1b] IR spectra of CO at the bridge site and CO at the atop site in the Pd / La-Al2O3 catalyst are shown. [Figure 2] 1 shows the catalytic performance of Pd / La-alumina coated catalysts with different La loadings. [Figure 3a] Figure 1 shows the IR intensity ratio of CO at the gem-dicarbonyl site to CO at the atop site for Rh / La-Al2O3 catalysts with different La loadings. [Figure 3b] IR spectra of CO at the gem-dicarbonyl site and CO at the atop site in the Rh / La-Al2O3 catalyst. DETAILED DESCRIPTION OF THE INVENTION

[0013] The present invention relates to the catalytic treatment of combustion exhaust gases, such as those produced by gasoline or other engines, and related catalyst articles and systems. More particularly, the present invention relates to the treatment of NO in vehicle exhaust systems. x , CO, and HC simultaneous treatment.

[0014] Most of the technical development of TWCs has focused on maintaining high dispersion of PGMs and improving their thermal stability, with the aim of improving their performance through the development of doped support materials with high thermal durability. To date, support dopants have been focused on their use as stabilizers for TWCs, with dopant contents of less than 5 wt% being sufficient to stabilize the materials. Indeed, La doping of alumina has shown that the surface area after thermal aging at 1000°C is 60 m2 compared to that of La = 0 wt%. 2 / g, 90m at La = 5 wt% 2 / g, and further doping with La did not result in further improvement of the surface area. For example, at La=20 wt%, the surface area was 67 m 2 / g. Surprisingly, the inventors have found that only heavily doped support materials effectively suppress CO poisoning of PGMs. The inventors have discovered a new role for the doping elements in the support material to effectively utilize PGM active sites even under high CO gas concentrations. The process of the present invention may reduce the amount of PGMs and lower the cost of the catalyst.

[0015] One aspect of the present disclosure relates to a catalyst composition comprising a platinum group metal (PGM) component and an inorganic oxide, wherein the PGM component has an infrared (IR) intensity ratio of bridge site CO to atop site CO of less than 3:1 under a reference CO adsorption procedure.

[0016] The PGM component may be Pd, Rh, or Pt. In some embodiments, the PGM component is Pd or Rh. In further embodiments, the PGM component is Pd.

[0017] The catalyst composition may contain up to 20 wt% of PGM components, preferably 0.05 to 10 wt%, more preferably 0.2 to 5 wt% of PGM components.

[0018] The catalyst composition may further comprise another PGM component.

[0019] The standard CO adsorption procedure may be as follows: First, the PGM catalyst powder is oxidized (10% O, 100 cc / min, He buffer) to remove organic contaminants, and then reduced under 3% H (100 cc / min, He buffer) to form the metallic PGM catalyst. Next, CO gas (1% CO, 100 cc / min, He buffer) is introduced for adsorption, and IR spectra are collected at room temperature (e.g., approximately 20-25 °C). The amount of powder sample may typically be 30 mg for IR measurements.

[0020] Typically, for CO adsorption on PGMs, two major states appear in the IR spectrum: for Pd at 2090 cm -1 For Rh, it is 2070cm -1 2090cm for front and rear or Pt -1 The IR absorption peaks before and after are attributable to atop sites where CO is bound to one PGM atom on the surface of the particle. -1 For Rh, it is 1870cm -1 1850cm for front and rear or Pt -1The IR absorption peaks before and after the peak can be assigned to bridge sites where CO is bonded to two PGM atoms on the particle surface. At bridge sites, CO is strongly adsorbed on the PGM surface. The CO at the bridge sites thus stabilized can block the PGM adsorption sites, i.e., poison the active sites with CO. At atop sites, CO adsorption on the PGM surface is weaker, which may promote the desorption and reaction of CO at the atop sites compared with CO at the bridge sites. The lower ratio of CO at the bridge sites to CO at the atop sites may mean that the effect of CO poisoning on the PGM tends to be suppressed.

[0021] The IR intensity ratio of CO at the bridge site to CO at the atop site in the PGM component may be less than 5:2, or less than 2:1.

[0022] The inorganic oxide may be an oxide of an element from Groups 2, 3, 4, 5, 13, or 14. The inorganic oxide is preferably a refractory metal oxide that exhibits chemical and physical stability at high temperatures, such as those associated with the exhaust of a gasoline engine. The inorganic oxide may be selected from the group consisting of alumina, silica, titania, and mixed or composite oxides thereof. More preferably, the inorganic oxide is alumina. The inorganic oxide may be a support material for the PGM component.

[0023] The inorganic oxide is preferably virgin and 80m 2 / g and a pore volume in the range of 0.1 to 4 mL / g. 2 High specific surface area inorganic oxides having a specific surface area of ​​more than 1 / g, such as high specific surface area alumina, are particularly preferred.

[0024] The inorganic oxide may be doped with a dopant. The dopant may be selected from the group consisting of La, Sr, Si, Ba, Y, Pr, Nd, and Ce. Preferably, the dopant may be La, Ba, or Ce. Most preferably, the dopant is La. The content of the dopant in the inorganic oxide (e.g., alumina) may be 10 to 30% by weight, 10 to 25% by weight, or 10 to 20% by weight. The content of the dopant in the inorganic oxide (e.g., alumina) may also be 15 to 30% by weight, 15 to 25% by weight, or 15 to 20% by weight.

[0025] The catalyst composition may further comprise an oxygen storage capacity (OSC) material and / or an alkali metal or alkaline earth metal component.

[0026] The OSC material is preferably selected from the group consisting of cerium oxide, zirconium oxide, ceria-zirconia mixed oxide, and alumina-ceria-zirconia mixed oxide. More preferably, the OSC material comprises ceria-zirconia mixed oxide. The ceria-zirconia mixed oxide may further comprise some dopants such as La, Nd, Y, Pr, etc.

[0027] The ceria-zirconia mixed oxide may have a zirconia to ceria molar ratio of at least 50:50, preferably greater than 60:40, and more preferably greater than 75:25. Additionally, the OSC material may function as a support material for the PGM components. In some embodiments, the PGM components are supported on the OSC material and inorganic oxide.

[0028] The OSC material (eg, ceria-zirconia mixed oxide) may be 10 to 90 wt %, preferably 25 to 75 wt %, more preferably 35 to 65 wt %, based on the total weight of the catalyst composition.

[0029] The OSC material and 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.

[0030] Alternatively, the OSC material and the inorganic oxide may 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.

[0031] In some embodiments, the alkali metal or alkaline earth metal may be deposited on the OSC material. Alternatively, or in addition, the alkali metal or alkaline earth metal may be deposited on the inorganic oxide. That is, in some embodiments, the alkali metal or alkaline earth metal may be deposited on, or present on, both the OSC material and the inorganic oxide.

[0032] Preferably, the alkali metal or alkaline earth metal is supported / deposited on an inorganic oxide (e.g., alumina). In addition to or instead of being in contact with the inorganic oxide, the alkali metal or alkaline earth metal may also be in contact with the OSC material and with the PGM component.

[0033] The alkali metal or alkaline earth metal is preferably barium or strontium. Preferably, when present, barium or strontium is present in an amount of 0.1 to 15 wt. %, more preferably 3 to 10 wt. %, based on the total weight of the catalyst composition.

[0034] Preferably, the barium is present as a BaCO3 composite material. Such materials can be preformed by any method known in the art, such as incipient wetness impregnation or spray drying.

[0035] Another aspect of the present disclosure relates to a catalyst composition comprising a platinum group metal (PGM) component and an inorganic oxide, wherein the PGM component has an IR intensity ratio of CO at gem-dicarbonyl sites to CO at atop sites of less than 5:1 under a standard CO adsorption procedure.

[0036] The PGM component may be Pd, Rh, or Pt. In some embodiments, the PGM component is Pd or Rh. In further embodiments, the PGM component is Rh.

[0037] The catalyst composition may contain up to 20 wt% of PGM components, preferably 0.05 to 10 wt%, more preferably 0.2 to 5 wt% of PGM components.

[0038] The catalyst composition may further comprise another PGM component.

[0039] Typically, for CO adsorption on PGMs, two major states appear in the IR spectrum: for Pd at 2090 cm -1 For Rh, it is 2070cm -1 2090cm for front and rear or Pt -1 The IR absorption peaks before and after are attributable to atop sites where CO is bound to one PGM atom on the surface of the particle. -1 For Rh, it is 1870cm -1 1850cm for front and rear or Pt -1 The IR absorption peaks before and after the peak can be assigned to bridge sites where CO is bonded to two PGM atoms on the particle surface. At bridge sites, CO is strongly adsorbed on the PGM surface, and the CO at the bridge sites stabilizes the PGM adsorption sites, blocking the PGM adsorption sites and potentially poisoning the active sites. At atop sites, CO adsorbs weaker on the PGM surface, which may promote the desorption and reaction of CO at the atop sites compared to CO at the bridge sites. The lower ratio of CO at the bridge sites to CO at the atop sites may mean that the effect of CO poisoning on the PGM tends to be suppressed.

[0040] In the case of Rh, an additional adsorption state, the gem-dicarbonyl form, involves two CO molecules bound to one Rh atom at the particle surface.-1 The IR absorption peaks before and after this peak can be assigned to the gem-dicarbonyl form of Rh. The gem-dicarbonyl is a stable local complex structure of CO-Rh, i.e., CO at the gem-dicarbonyl site is less catalytically reactive than CO at the atop site in Rh due to CO poisoning of the active site. The lower ratio of CO at the gem-dicarbonyl site to CO at the atop site may mean that the effect of CO poisoning on Rh tends to be suppressed.

[0041] The IR intensity ratio of CO at gem-dicarbonyl sites to CO at atop sites in the PGM component may be less than 4:1, less than 3:1, or less than 5:2.

[0042] The inorganic oxide may be an oxide of an element from Groups 2, 3, 4, 5, 13, or 14. The inorganic oxide is preferably a refractory metal oxide that exhibits chemical and physical stability at high temperatures, such as those associated with the exhaust of a gasoline engine. The inorganic oxide may be selected from the group consisting of alumina, silica, titania, and mixed or composite oxides thereof. More preferably, the inorganic oxide is alumina. The inorganic oxide may be a support material for the PGM component.

[0043] The inorganic oxide is preferably virgin and 80m 2 / g and a pore volume in the range of 0.1 to 4 mL / g. 2 High specific surface area inorganic oxides having a specific surface area of ​​more than 1 / g, such as high specific surface area alumina, are particularly preferred.

[0044] The inorganic oxide may be doped with a dopant. The dopant may be selected from the group consisting of La, Sr, Si, Ba, Y, Pr, Nd, and Ce. Preferably, the dopant may be La, Ba, or Ce. Most preferably, the dopant is La. The content of the dopant in the inorganic oxide (e.g., alumina) may be 10 to 30% by weight, 10 to 25% by weight, or 10 to 20% by weight. The content of the dopant in the inorganic oxide (e.g., alumina) may also be 15 to 30% by weight, 15 to 25% by weight, or 15 to 20% by weight.

[0045] The catalyst composition may further comprise an oxygen storage capacity (OSC) material and / or an alkali metal or alkaline earth metal component.

[0046] The OSC material is preferably selected from the group consisting of cerium oxide, zirconium oxide, ceria-zirconia mixed oxide, and alumina-ceria-zirconia mixed oxide. More preferably, the OSC material comprises ceria-zirconia mixed oxide. The ceria-zirconia mixed oxide may further comprise some dopants such as La, Nd, Y, Pr, etc.

[0047] The ceria-zirconia mixed oxide may have a zirconia to ceria molar ratio of at least 50:50, preferably greater than 60:40, and more preferably greater than 75:25. Additionally, the OSC material may function as a support material for the PGM components. In some embodiments, the PGM components are supported on the OSC material and inorganic oxide.

[0048] The OSC material (eg, ceria-zirconia mixed oxide) may be 10 to 90 wt %, preferably 25 to 75 wt %, more preferably 35 to 65 wt %, based on the total weight of the catalyst composition.

[0049] The OSC material and 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.

[0050] Alternatively, the OSC material and the inorganic oxide may 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.

[0051] In some embodiments, the alkali metal or alkaline earth metal may be deposited on the OSC material. Alternatively, or in addition, the alkali metal or alkaline earth metal may be deposited on the inorganic oxide. That is, in some embodiments, the alkali metal or alkaline earth metal may be deposited on, or present on, both the OSC material and the inorganic oxide.

[0052] Preferably, the alkali metal or alkaline earth metal is supported / deposited on an inorganic oxide (e.g., alumina). In addition to or instead of being in contact with the inorganic oxide, the alkali metal or alkaline earth metal may also be in contact with the OSC material and with the PGM component.

[0053] The alkali metal or alkaline earth metal is preferably barium or strontium. Preferably, when present, barium or strontium is present in an amount of 0.1 to 15 wt. %, more preferably 3 to 10 wt. %, based on the total weight of the catalyst composition.

[0054] Preferably, the barium is present as a BaCO3 composite material. Such materials can be preformed by any method known in the art, such as incipient wetness impregnation or spray drying.

[0055] Another aspect of the present disclosure relates to a catalytic article for treating exhaust gases, the catalytic article comprising: a substrate; and a first catalytic region on the substrate, the first catalytic region comprising a first PGM component and a first inorganic oxide, wherein the PGM component has an IR intensity ratio of bridge site CO to atop site CO of less than 3:1 under a reference CO adsorption procedure.

[0056] The first PGM component may be Pd, Rh, or Pt. In some embodiments, the first PGM component is Pd or Rh. In further embodiments, the first PGM component is Pd. In yet other further embodiments, the first catalytic region is substantially free of PGMs other than palladium.

[0057] First catalyst zone up to 350g / ft 3 Preferably, the first catalyst zone comprises a first PGM component of between 10 and 300 g / ft 3 , more preferably 25 to 150 g / ft 3 The first PGM component may include:

[0058] The IR intensity ratio of CO at the bridge site to CO at the atop site in the first PGM component may be less than 5:2, or less than 2:1.

[0059] The first inorganic oxide may be an oxide of an element from Groups 2, 3, 4, 5, 13, or 14. The first inorganic oxide is preferably a refractory metal oxide that exhibits chemical and physical stability at high temperatures, such as those associated with the exhaust of a gasoline engine. The first inorganic oxide may be selected from the group consisting of alumina, silica, titania, and mixed or composite oxides thereof. More preferably, the first inorganic oxide is alumina. The first inorganic oxide may be a support material for the first PGM component.

[0060] The first inorganic oxide is preferably virgin and 80 ml 2 / g and a pore volume in the range of 0.1 to 4 mL / g.2 High specific surface area inorganic oxides having a specific surface area of ​​more than 1 / g, such as high specific surface area alumina, are particularly preferred.

[0061] The first inorganic oxide may be doped with a dopant. The dopant may be selected from the group consisting of La, Sr, Si, Ba, Y, Pr, Nd, and Ce. Preferably, the dopant may be La, Ba, or Ce. Most preferably, the dopant is La. The content of the dopant in the first inorganic oxide (e.g., alumina) may be 10 to 30 wt%, 10 to 25 wt%, or 10 to 20 wt%. The content of the dopant in the first inorganic oxide (e.g., alumina) may also be 15 to 30 wt%, 15 to 25 wt%, or 15 to 20 wt%.

[0062] The first catalyst region may further include a first oxygen storage capacity (OSC) material and / or a first alkali metal or alkaline earth metal component.

[0063] The total washcoat loading of the first catalyst region is 0.1 to 5 g / in 3 Preferably, the total washcoat loading of the first catalyst region is 0.5 to 3.5 g / in 3 and most preferably, the total washcoat loading of the first catalyst region is 1 to 2.5 g / in 3 is.

[0064] The first OSC material is preferably selected from the group consisting of cerium oxide, zirconium oxide, ceria-zirconia mixed oxide, and alumina-ceria-zirconia mixed oxide. More preferably, the first OSC material comprises ceria-zirconia mixed oxide. The ceria-zirconia mixed oxide may further comprise some dopants such as La, Nd, Y, Pr, etc.

[0065] The ceria-zirconia mixed oxide may have a zirconia to ceria molar ratio of at least 50:50, preferably greater than 60:40, and more preferably greater than 75:25. Additionally, the first OSC material may function as a support material for the first PGM component. In some embodiments, the first PGM component is supported on the first OSC material and the first inorganic oxide.

[0066] The first OSC material (e.g., ceria-zirconia mixed oxide) may be 10-90 wt %, preferably 25-75 wt %, and more preferably 35-65 wt %, based on the total washcoat loading of the first catalyst region.

[0067] The loading of the first OSC material in the first catalyst region is 1.5 g / in 3 In some embodiments, the loading of the first OSC material in the first catalyst region can be less than 1.2 g / in 3 , 1.0g / in 3 , 0.9g / in 3 , 0.8g / in 3 , 0.7g / in 3 , or 0.6 g / in 3 The following is the result.

[0068] The first OSC material and the 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.

[0069] Alternatively, the first OSC material and the first inorganic oxide may 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.

[0070] In some embodiments, the first alkali metal or alkaline earth metal may be deposited on the first OSC material. Alternatively, or in addition, the first alkali metal or alkaline earth metal may be deposited on the inorganic oxide. That is, in some embodiments, the first alkali metal or alkaline earth metal may be deposited on, or present on, both the first OSC material and the first inorganic oxide.

[0071] Preferably, the first alkali or alkaline earth metal is supported / deposited on a first inorganic oxide (e.g., alumina). In addition to or instead of being in contact with the first inorganic oxide, the first alkali or alkaline earth metal may also be in contact with the first OSC material and with the first PGM component.

[0072] The first alkali metal or alkaline earth metal is preferably barium or strontium. Preferably, the barium or strontium, if present, is present in an amount of 0.1 to 15 wt %, more preferably 3 to 10 wt %, based on the total washcoat loading of the first catalyst region.

[0073] Preferably, the barium is present as a BaCO3 composite material. Such materials can be preformed by any method known in the art, such as incipient wetness impregnation or spray drying.

[0074] The catalytic article may further include a second catalytic region, which may include a second PGM component, a second oxygen storage capacity (OSC) material, a second alkali metal or alkaline earth metal component, and / or a second inorganic oxide.

[0075] The second PGM component may be selected from the group consisting of palladium, platinum, rhodium, and mixtures thereof. In some embodiments, when the first PGM component is Rh, the second PGM component may be Pd. In other embodiments, when the first PGM component is Pd, the second PGM component may be Rh.

[0076] Second catalyst area up to 350g / ft 3 Preferably, the second catalyst zone comprises 10 to 300 g / ft of a second PGM component. 3 , more preferably 25 to 150 g / ft 3 The second PGM component may include:

[0077] The total washcoat loading of the second catalyst region is 0.1 to 5 g / in 3 Preferably, the total washcoat loading of the second catalyst region is 0.5 to 3.5 g / in 3 and most preferably, the total washcoat loading of the second catalyst region is 1 to 2.5 g / in 3 is.

[0078] The second inorganic oxide is preferably an oxide of an element of Groups 2, 3, 4, 5, 13, or 14. The second inorganic oxide is preferably selected from the group consisting of alumina, magnesia, lanthana, silica, neodymium, praseodymium, yttrium oxide, titania, niobia, tantalum oxide, molybdenum oxide, tungsten oxide, and mixed oxides or composite oxides thereof. More preferably, the second inorganic oxide is selected from the group consisting of alumina, magnesia, silica, lanthanum, neodymium, praseodymium, yttrium oxide, and mixed oxides or composite oxides thereof. Particularly preferred is alumina, a lanthanum / alumina composite oxide, or a magnesia / alumina composite oxide. One particularly preferred second inorganic oxide is a lanthanum-alumina composite oxide. The second inorganic oxide may be a support material for the second PGM component and / or a support material for the second alkali metal or alkaline earth metal.

[0079] The second inorganic oxide is preferably virgin and 80 ml 2 / g and a pore volume in the range of 0.1 to 4 mL / g. 2 Particularly preferred are high-surface-area inorganic oxides, such as high-surface-area alumina, having a specific surface area of ​​more than 1 / g. Another preferred second inorganic oxide is a lanthanum / alumina composite oxide, which optionally further contains a cerium-containing component, such as ceria. In such cases, the ceria may be present on the surface of the lanthanum / alumina composite oxide, for example, as a coating.

[0080] Alternatively, the second inorganic oxide may also have the same characteristics as the first inorganic oxide (e.g., the dopant may be 10-30% and / or the IR intensity ratio of bridge site CO to atop site CO in the second PGM component may be less than 3:1).

[0081] The second OSC material is preferably selected from the group consisting of cerium oxide, zirconium oxide, ceria-zirconia mixed oxide, and alumina-ceria-zirconia mixed oxide. More preferably, the second OSC material comprises ceria-zirconia mixed oxide. The ceria-zirconia mixed oxide may further comprise some dopants such as La, Nd, Y, Pr, etc.

[0082] The ceria-zirconia mixed oxide may have a zirconia to ceria molar ratio of at least 50:50, preferably greater than 60:40, and more preferably greater than 75:25. Additionally, the second OSC material may function as a support material for the second PGM component. In some embodiments, the second PGM component is supported on the second OSC material and the second inorganic oxide.

[0083] The second OSC material (e.g., ceria-zirconia mixed oxide) may be 10-90 wt %, preferably 25-75 wt %, more preferably 35-65 wt %, based on the total washcoat loading of the second catalyst region.

[0084] The loading of the second OSC material in the second catalyst region is 1.5 g / in 3 In some embodiments, the loading of the second OSC material in the second catalyst region can be less than 1.2 g / in 3 , 1.0g / in 3 , 0.9g / in 3 , 0.8g / in 3 , 0.7g / in 3 , or 0.6 g / in 3 The following is the result.

[0085] The second OSC material and the second 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.

[0086] Alternatively, the second OSC material and the second inorganic oxide may 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.

[0087] In some embodiments, the second alkali metal or alkaline earth metal may be deposited on the second OSC material. Alternatively, or in addition, the second alkali metal or alkaline earth metal may be deposited on the second inorganic oxide. That is, in some embodiments, the second alkali metal or alkaline earth metal may be deposited on, or present on, both the second OSC material and the second inorganic oxide.

[0088] Preferably, the second alkali or alkaline earth metal is supported / deposited on a second inorganic oxide (e.g., alumina). In addition to or instead of being in contact with the second inorganic oxide, the second alkali or alkaline earth metal may also be in contact with the second OSC material and with the second PGM component.

[0089] The second alkali or alkaline earth metal is preferably barium or strontium. Preferably, when present, the barium or strontium is present in an amount of 0.1 to 15 wt %, more preferably 3 to 10 wt %, based on the total washcoat loading of the second catalyst region.

[0090] Preferably, the barium is present as a BaCO3 composite material. Such materials can be preformed by any method known in the art, such as incipient wetness impregnation or spray drying.

[0091] In some embodiments, the first PGM component and the second PGM component have a weight ratio of 60:1 to 1:60. Preferably, the first PGM component and the second PGM component have a weight ratio of 30:1 to 1:30. More preferably, the first PGM component and the second PGM component have a weight ratio of 20:1 to 1:20. Most preferably, the first PGM component and the second PGM component have a weight ratio of 15:1 to 1:15.

[0092] Another aspect of the present disclosure relates to a catalytic article for treating exhaust gases, the catalytic article comprising: a substrate; and a first catalytic region on the substrate, the first catalytic region comprising a first PGM component and a first inorganic oxide, wherein the PGM component has an IR intensity ratio of CO at gem-dicarbonyl sites to CO at atop sites that is less than 5:1 under a reference CO adsorption procedure.

[0093] The first PGM component may be Pd, Rh, or Pt. In some embodiments, the first PGM component is Pd or Rh. In further embodiments, the first PGM component is Rh. In yet other further embodiments, the first catalyst region is substantially free of PGMs other than Rh.

[0094] First catalyst zone up to 350g / ft 3 Preferably, the first catalyst zone comprises a first PGM component of between 10 and 300 g / ft 3 , more preferably 25 to 150 g / ft 3 The first PGM component may include:

[0095] The IR intensity ratio of CO at the gem-dicarbonyl sites to CO at the atop sites in the first PGM component may be less than 4:1, less than 3:1, or less than 5:2.

[0096] The first inorganic oxide may be an oxide of an element from Groups 2, 3, 4, 5, 13, or 14. The first inorganic oxide is preferably a refractory metal oxide that exhibits chemical and physical stability at high temperatures, such as those associated with the exhaust of a gasoline engine. The first inorganic oxide may be selected from the group consisting of alumina, silica, titania, and mixed or composite oxides thereof. More preferably, the first inorganic oxide is alumina. The first inorganic oxide may be a support material for the first PGM component.

[0097] The first inorganic oxide is preferably virgin and 80 ml 2 / g and a pore volume in the range of 0.1 to 4 mL / g. 2 High specific surface area inorganic oxides having a specific surface area of ​​more than 1 / g, such as high specific surface area alumina, are particularly preferred.

[0098] The first inorganic oxide may be doped with a dopant. The dopant may be selected from the group consisting of La, Sr, Si, Ba, Y, Pr, Nd, and Ce. Preferably, the dopant may be La, Ba, or Ce. Most preferably, the dopant is La. The content of the dopant in the first inorganic oxide (e.g., alumina) may be 10 to 30 wt%, 10 to 25 wt%, or 10 to 20 wt%. The content of the dopant in the first inorganic oxide (e.g., alumina) may also be 15 to 30 wt%, 15 to 25 wt%, or 15 to 20 wt%.

[0099] The first catalyst region may further include a first oxygen storage capacity (OSC) material and / or a first alkali metal or alkaline earth metal component.

[0100] The total washcoat loading of the first catalyst region is 0.1 to 5 g / in 3 Preferably, the total washcoat loading of the first catalyst region is 0.5 to 3.5 g / in 3 and most preferably, the total washcoat loading of the first catalyst region is 1 to 2.5 g / in 3 is.

[0101] The first OSC material is preferably selected from the group consisting of cerium oxide, zirconium oxide, ceria-zirconia mixed oxide, and alumina-ceria-zirconia mixed oxide. More preferably, the first OSC material comprises ceria-zirconia mixed oxide. The ceria-zirconia mixed oxide may further comprise some dopants such as La, Nd, Y, Pr, etc.

[0102] The ceria-zirconia mixed oxide may have a zirconia to ceria molar ratio of at least 50:50, preferably greater than 60:40, and more preferably greater than 75:25. Additionally, the first OSC material may function as a support material for the first PGM component. In some embodiments, the first PGM component is supported on the first OSC material and the first inorganic oxide.

[0103] The first OSC material (e.g., ceria-zirconia mixed oxide) may be 10-90 wt %, preferably 25-75 wt %, and more preferably 35-65 wt %, based on the total washcoat loading of the first catalyst region.

[0104] The loading of the first OSC material in the first catalyst region is 1.5 g / in 3 In some embodiments, the loading of the first OSC material in the first catalyst region can be less than 1.2 g / in 3 , 1.0g / in 3 , 0.9g / in 3 , 0.8g / in 3 , 0.7g / in 3 , or 0.6 g / in 3 The following is the result.

[0105] The first OSC material and the 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.

[0106] Alternatively, the first OSC material and the first inorganic oxide may 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.

[0107] In some embodiments, the first alkali metal or alkaline earth metal may be deposited on the first OSC material. Alternatively, or in addition, the first alkali metal or alkaline earth metal may be deposited on the inorganic oxide. That is, in some embodiments, the first alkali metal or alkaline earth metal may be deposited on, or present on, both the first OSC material and the first inorganic oxide.

[0108] Preferably, the first alkali or alkaline earth metal is supported / deposited on a first inorganic oxide (e.g., alumina). In addition to or instead of being in contact with the first inorganic oxide, the first alkali or alkaline earth metal may also be in contact with the first OSC material and with the first PGM component.

[0109] The first alkali metal or alkaline earth metal is preferably barium or strontium. Preferably, the barium or strontium, if present, is present in an amount of 0.1 to 15 wt %, more preferably 3 to 10 wt %, based on the total washcoat loading of the first catalyst region.

[0110] Preferably, the barium is present as a BaCO3 composite material. Such materials can be preformed by any method known in the art, such as incipient wetness impregnation or spray drying.

[0111] The catalytic article may further include a second catalytic region, which may include a second PGM component, a second oxygen storage capacity (OSC) material, a second alkali metal or alkaline earth metal component, and / or a second inorganic oxide.

[0112] The second PGM component may be selected from the group consisting of palladium, platinum, rhodium, and mixtures thereof. In some embodiments, when the first PGM component is Rh, the second PGM component may be Pd. In other embodiments, when the first PGM component is Pd, the second PGM component may be Rh.

[0113] Second catalyst area up to 350g / ft 3 Preferably, the second catalyst zone comprises 10 to 300 g / ft of a second PGM component. 3 , more preferably 25 to 150 g / ft 3 The second PGM component may include:

[0114] The total washcoat loading of the second catalyst region is 0.1 to 5 g / in 3 Preferably, the total washcoat loading of the second catalyst region is 0.5 to 3.5 g / in 3 and most preferably, the total washcoat loading of the second catalyst region is 1 to 2.5 g / in 3 is.

[0115] The second inorganic oxide is preferably an oxide of an element of Groups 2, 3, 4, 5, 13, or 14. The second inorganic oxide is preferably selected from the group consisting of alumina, magnesia, lanthana, silica, neodymium, praseodymium, yttrium oxide, titania, niobia, tantalum oxide, molybdenum oxide, tungsten oxide, and mixed oxides or composite oxides thereof. More preferably, the second inorganic oxide is selected from the group consisting of alumina, magnesia, silica, lanthanum, neodymium, praseodymium, yttrium oxide, and mixed oxides or composite oxides thereof. Particularly preferred is alumina, a lanthanum / alumina composite oxide, or a magnesia / alumina composite oxide. One particularly preferred second inorganic oxide is a lanthanum-alumina composite oxide. The second inorganic oxide may be a support material for the second PGM component and / or a support material for the second alkali metal or alkaline earth metal.

[0116] The second inorganic oxide is preferably virgin and 80 ml 2 / g and a pore volume in the range of 0.1 to 4 mL / g. 2 Particularly preferred are high-surface-area inorganic oxides, such as high-surface-area alumina, having a specific surface area of ​​more than 1 / g. Another preferred second inorganic oxide is a lanthanum / alumina composite oxide, which optionally further contains a cerium-containing component, such as ceria. In such cases, the ceria may be present on the surface of the lanthanum / alumina composite oxide, for example, as a coating.

[0117] Alternatively, the second inorganic oxide may also have the same characteristics as the first inorganic oxide (e.g., the dopant may be 10-30% and / or the IR intensity ratio of bridge site CO to atop site CO in the second PGM component may be less than 3:1).

[0118] The second OSC material is preferably selected from the group consisting of cerium oxide, zirconium oxide, ceria-zirconia mixed oxide, and alumina-ceria-zirconia mixed oxide. More preferably, the second OSC material comprises ceria-zirconia mixed oxide. The ceria-zirconia mixed oxide may further comprise some dopants such as La, Nd, Y, Pr, etc.

[0119] The ceria-zirconia mixed oxide may have a zirconia to ceria molar ratio of at least 50:50, preferably greater than 60:40, and more preferably greater than 75:25. Additionally, the second OSC material may function as a support material for the second PGM component. In some embodiments, the second PGM component is supported on the second OSC material and the second inorganic oxide.

[0120] The second OSC material (e.g., ceria-zirconia mixed oxide) may be 10-90 wt %, preferably 25-75 wt %, more preferably 35-65 wt %, based on the total washcoat loading of the second catalyst region.

[0121] The loading of the second OSC material in the second catalyst region is 1.5 g / in 3 In some embodiments, the loading of the second OSC material in the second catalyst region may be less than 1.2 g / in 3 , 1.0g / in 3 , 0.9g / in 3 , 0.8g / in 3 , 0.7g / in 3 , or 0.6 g / in 3 The following is the result.

[0122] The second OSC material and the second 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.

[0123] Alternatively, the second OSC material and the second inorganic oxide may 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.

[0124] In some embodiments, the second alkali metal or alkaline earth metal may be deposited on the second OSC material. Alternatively, or in addition, the second alkali metal or alkaline earth metal may be deposited on the second inorganic oxide. That is, in some embodiments, the second alkali metal or alkaline earth metal may be deposited on, or present on, both the second OSC material and the second inorganic oxide.

[0125] Preferably, the second alkali or alkaline earth metal is supported / deposited on a second inorganic oxide (e.g., alumina). In addition to or instead of being in contact with the second inorganic oxide, the second alkali or alkaline earth metal may also be in contact with the second OSC material and with the second PGM component.

[0126] The second alkali or alkaline earth metal is preferably barium or strontium. Preferably, when present, the barium or strontium is present in an amount of 0.1 to 15 wt %, more preferably 3 to 10 wt %, based on the total washcoat loading of the second catalyst region.

[0127] Preferably, the barium is present as a BaCO3 composite material. Such materials can be preformed by any method known in the art, such as incipient wetness impregnation or spray drying.

[0128] In some embodiments, the first PGM component and the second PGM component have a weight ratio of 60:1 to 1:60. Preferably, the first PGM component and the second PGM component have a weight ratio of 30:1 to 1:30. More preferably, the first PGM component and the second PGM component have a weight ratio of 20:1 to 1:20. Most preferably, the first PGM component and the second PGM component have a weight ratio of 15:1 to 1:15.

[0129] Another aspect of the present disclosure relates to a catalytic article for treating exhaust gases, the catalytic article comprising: a substrate; a first catalytic region on the substrate; and a second catalytic region on the substrate, wherein the first catalytic region comprises a first PGM component and a first inorganic oxide; the second catalytic region comprises a second PGM component and a second inorganic oxide; and at least one of the first inorganic oxide and the second inorganic oxide is doped with 10-30% dopant.

[0130] The catalyst article may have a ratio of CO at bridge sites to CO at atop sites in the first PGM component (eg, Pd) of less than 3:1 under a reference CO adsorption procedure.

[0131] The catalyst article may have a ratio of CO on gem-dicarbonyl sites to CO on atop sites in the second PGM component (eg, Rh) of less than 5:1 under a baseline CO adsorption procedure.

[0132] The dopants for the first inorganic oxide or the second inorganic oxide are each independently selected from the group consisting of La, Sr, Si, Ba, Y, Pr, Nd, and Ce. In further embodiments, the dopant for the first inorganic oxide or the second inorganic oxide is La.

[0133] All features, ranges, limitations of the above disclosure in the third and / or fourth aspects of the disclosure apply to this fifth aspect of the disclosure.

[0134] The catalyst article of the present invention may contain additional components known to those skilled in the art. For example, the composition of the present invention may further comprise at least one binder and / or at least one surfactant. When a binder is present, a dispersible alumina binder is preferred.

[0135] Preferably, the substrate is a flow-through monolith or a wall-flow gasoline particulate filter. More preferably, the substrate is a flow-through monolith.

[0136] The flow-through monolith substrate has a first surface and a second surface defining a longitudinal direction therebetween. The flow-through monolith substrate has a plurality of channels extending between the first surface and the second surface. The plurality of channels extend longitudinally and provide a plurality of interior surfaces (e.g., wall surfaces defining each channel). Each of the plurality of channels has an opening in the first surface and an opening in the second surface. For the avoidance of doubt, a flow-through monolith substrate is not a wall-flow filter.

[0137] The first surface is typically at the inlet end of the substrate and the second surface is at the outlet end of the substrate.

[0138] The channels may be of constant width, and each of the plurality of channels may have a uniform channel width.

[0139] Preferably, in a plane perpendicular to the longitudinal direction, the monolith substrate has 100 to 900 channels per square inch, preferably 300 to 750 channels per square inch. For example, on the first face, the density of the open first channels and closed second channels is 300 to 750 channels per square inch. The channels may have cross sections that are rectangular, square, circular, oval, triangular, hexagonal, or other polygonal shapes.

[0140] The monolith substrate acts as a support to hold the catalytic material. Suitable materials for forming the monolith 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 monolith substrates are well known in the art.

[0141] It should be noted that the flow-through monolith substrates described herein are unitary components (i.e., a single brick). Nevertheless, when forming an effluent treatment system, the monolith used may be formed by bonding multiple channels together, or may be formed by bonding multiple smaller monoliths together as described herein. Such techniques, along with suitable casings and configurations for effluent treatment systems, are known in the art.

[0142] In embodiments in which the catalyst article of the present invention comprises a ceramic substrate, the ceramic substrate may be made of any suitable refractory material, such as alumina, silica, titania, ceria, zirconia, magnesia, zeolites, silicon nitride, silicon carbide, zirconium silicate, magnesium silicate, aluminosilicates and metalloaluminosilicates (such as cordierite and spodumene), or mixtures or mixed oxides of any two or more thereof. Cordierite, magnesium aluminosilicate, and silicon carbide are particularly preferred.

[0143] In embodiments in which the catalytic article of the present invention comprises a metal substrate, the metal substrate may be made of any suitable metal, particularly refractory metals and metal alloys such as titanium and stainless steel, and ferritic alloys containing iron, nickel, chromium, and / or aluminum, in addition to other trace metals.

[0144] In some embodiments, the first catalytic region may be supported / deposited directly on the substrate, and in further embodiments, the second catalytic region may be supported / deposited on the first catalytic region.

[0145] In other embodiments, the second catalytic region may be supported / deposited directly on the substrate. In further embodiments, the first catalytic region is supported / deposited on the second catalytic region.

[0146] Another aspect of the present disclosure is a method for producing NOx using the catalytic articles described herein. x The present invention relates to a method for treating vehicle exhaust gases containing CO, HC, and CO. Catalytic converters equipped with TWCs made according to the present invention have demonstrated improved catalytic performance compared to conventional TWCs (see, for example, Examples 3 and 5, and Tables 2 and 3).

[0147] Another aspect of the present disclosure relates to a system for treating vehicle exhaust gases that includes a catalytic article as described herein along with a conduit for delivering exhaust gases through the system.

[0148] definition The term "washcoat" is known in the art and typically refers to an adherent coating that is applied to a substrate during the manufacture of a catalyst.

[0149] 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.

[0150] As used herein, the term "mixed oxide" generally refers to a single-phase mixture of oxides, as conventionally known in the art. As used herein, the term "complex oxide" generally refers to a composition of oxides having two or more phases, as conventionally known in the art.

[0151] As used herein, the phrase "consisting essentially of" limits the scope of a feature to include the specified material and any other materials or steps, such as, for example, trace impurities, that do not substantially affect the basic properties of the feature. The phrase "consisting essentially of" encompasses the phrase "consisting of."

[0152] As used herein with respect to a material, the term "substantially free" typically means that the substance is present in a small amount, e.g., 5% by weight or less, preferably 2% by weight or less, more preferably 1% by weight or less, relative to the contents of the region, layer, or zone. The term "substantially free" encompasses the term "free."

[0153] As used herein with respect to a material, the term "essentially free" typically means that the material is present in trace amounts, e.g., 1% by weight or less, preferably 0.5% by weight or less, and more preferably 0.1% by weight or less, relative to the contents of a region, layer, or zone. The term "essentially free" encompasses the term "free."

[0154] As used herein, any reference to an amount, particularly a total amount, of dopant expressed as a weight percent refers to the weight of the support material or refractory metal oxide thereof.

[0155] As used herein, the term "loading" refers to g / ft on a metal weight basis. 3 Refers to measurements in units of .

[0156] The following examples are merely illustrative of the present invention, and those skilled in the art will recognize many variations that are within the spirit and scope of the claims. [Example]

[0157] material All materials were commercially available and obtained from known sources unless otherwise stated.

[0158] Basic procedure for synthesizing doped inorganic oxides Surface area approximately 150m 2 Commercially available γ-AlO was used as the AlO support, and La was added to the AlO support as follows: The AlO support was impregnated with an aqueous solution containing La(NO) (La concentration = 2.0 mmol / mL) to the target La loading. The AlO support was then dried at 120 °C for 2 hours and calcined in air at 600 °C for 2 hours to obtain a La-doped AlO material.

[0159] Example 1 Catalyst powders containing La-doped alumina with La contents of 1, 4, 10, and 15 wt% and 3 wt% Pd were exposed to CO under a standard CO adsorption procedure. The ratio of CO at the bridge site to CO at the atop site was detected by IR spectroscopy.

[0160] As shown in Figure 1a and Figure 1b, the IR intensity ratio of CO at the bridge site to CO at the atop site decreased with increasing La content in the alumina support. The decrease in the ratio of CO at the bridge site to CO at the atop site may indicate a tendency for CO poisoning of PGM to be suppressed.

[0161] Example 2 A catalyst consisting of La-doped alumina with a La content of 5 wt % or 10 wt % and supporting 1 wt % Pd, coated on a cordierite substrate, was subjected to a catalytic performance test using a simulated exhaust gas having the composition shown in Table 1 under the following conditions.

[0162] In the catalytic performance test, HC, CO, and NO x The temperature at which each component is converted by 50% was evaluated. A lower temperature at which 50% is converted means better performance as an exhaust gas purification catalyst.

[0163] In the catalyst performance test, the gas flow rate was set at 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 to measure the conversion rate.

[0164] [Table 1]

[0165] As shown in FIG. 2, the temperatures at 50% conversion for HC, CO, and NO were lower for the high-content La-doped alumina with La=10 wt % than for 5 wt %.

[0166] Example 3 Catalyst 1 (comparison) Catalyst 1 is a ternary (Pd-Rh) catalyst with a double-layer structure. The bottom layer consists of Pd supported on a washcoat consisting of a first CeZr mixed oxide, 4 wt. % La-stabilized alumina, and a Ba promoter. The washcoat loading of the bottom layer is approximately 2.5 g / in. 3 The Pd loading is 90 g / ft 3 The upper layer consisted of Rh supported on a washcoat consisting of a second CeZr mixed oxide and La-stabilized alumina. The washcoat loading of the upper layer was approximately 1.0 g / in. 3 The Rh loading is 9 g / ft 3 The total washcoat loading of catalyst 1 was approximately 3.5 g / in 3 It was.

[0167] Catalyst 2 Catalyst 2 is a ternary (Pd-Rh) catalyst with a double-layer structure. The bottom layer consists of Pd supported on a washcoat consisting of a first CeZr mixed oxide, a highly La-doped alumina (15 wt%), and a Ba promoter. The washcoat loading of the bottom layer is approximately 2.5 g / in. 3 The Pd loading is 90 g / ft 3The upper layer consisted of Rh supported on a washcoat consisting of a second CeZr mixed oxide and La-stabilized alumina. The washcoat loading of the upper layer was approximately 1.0 g / in. 3 The Rh loading is 9 g / ft 3 The total washcoat loading of catalyst 2 was approximately 3.5 g / in 3 It was.

[0168] Comparative Catalyst 1 and Catalyst 2 were bench aged for 75 hours at a peak temperature of 950°C using a fuel cut aging cycle, and vehicle emissions were measured in a commercial vehicle with a 1.5L engine. Emissions were measured before and after the catalyst.

[0169] [Table 2]

[0170] As shown in Table 2, Catalyst 2 had a significantly lower concentration of HC, NMHC, CO, and NO compared to Comparative Catalyst 1. x showed a significant decrease in emissions.

[0171] Example 4 Catalyst powders containing La-doped alumina with La contents of 1, 4, 10, and 15 wt% and 3 wt% Rh were exposed to CO under a standard CO adsorption procedure. The ratio of CO at the gem-dicarbonyl site to CO at the atop site was detected by IR spectroscopy.

[0172] As shown in Figures 3a and 3b, the IR intensity ratio of CO at the gem-dicarbonyl site to CO at the atop site decreased with increasing La content in the alumina support. The decrease in the ratio of CO at the gem-dicarbonyl site to CO at the atop site may indicate a tendency for CO poisoning of PGM to be suppressed.

[0173] Example 5 Catalyst 3 (comparison) Catalyst 3 is a ternary (Pd-Rh) catalyst with a double-layer structure. The bottom layer consists of Pd supported on a washcoat consisting of a first CeZr mixed oxide, 4 wt. % La-stabilized alumina, and a Ba promoter. The washcoat loading of the bottom layer is approximately 2.0 g / in. 3 The Pd loading was 140 g / ft 3 The upper layer consisted of Rh supported on a washcoat consisting of a second CeZr mixed oxide and La-stabilized alumina. The washcoat loading of the upper layer was approximately 1.0 g / in. 3 The Rh loading is 25 g / ft 3 The total washcoat loading of catalyst 3 was approximately 3.0 g / in 3 It was.

[0174] Catalyst 4 Catalyst 4 is a ternary (Pd-Rh) catalyst with a double-layer structure. The bottom layer consists of Pd supported on a washcoat consisting of a first CeZr mixed oxide, 4 wt. % La-stabilized alumina, and a Ba promoter. The washcoat loading of the bottom layer is approximately 2.0 g / in. 3 The Pd loading was 140 g / ft 3 The upper layer consisted of Rh supported on a washcoat consisting of a second CeZr mixed oxide and a highly La-doped alumina at 15 wt %. The washcoat loading of the upper layer was approximately 1.0 g / in 3 The Rh loading is 25 g / ft 3 The total washcoat loading of catalyst 4 was approximately 3.0 g / in 3 It was.

[0175] Catalyst 5 Catalyst 5 is a ternary (Pd-Rh) catalyst with a double-layer structure. The bottom layer consists of Pd supported on a washcoat consisting of a first CeZr mixed oxide, a highly La-doped alumina (15 wt%), and a Ba promoter. The washcoat loading of the bottom layer is approximately 2.0 g / in. 3 The Pd loading was 140 g / ft 3The upper layer consisted of Rh supported on a washcoat consisting of a second CeZr mixed oxide and a highly La-doped alumina at 15 wt %. The washcoat loading of the upper layer was approximately 1.0 g / in 3 The Rh loading is 25 g / ft 3 The total washcoat loading of catalyst 5 was about 3.0 g / in 3 It was.

[0176] Comparative Catalyst 3, Catalyst 4, and Catalyst 5 were bench aged for 75 hours at a peak temperature of 950°C using a fuel cut aging cycle, and vehicle emissions were measured in a commercial vehicle with a 1.5 L engine.

[0177] [Table 3]

[0178] As shown in Table 3, Catalyst 4 and Catalyst 5 had significantly lower concentrations of HC, NMHC, CO, and NO compared to Comparative Catalyst 3. x showed a significant decrease in emissions. The disclosure of this specification may include the following aspects. (Aspect 1) 1. A catalyst composition comprising a platinum group metal (PGM) component and an inorganic oxide, wherein the PGM component has an infrared (IR) intensity ratio of CO at bridge sites to CO at atop sites of less than 3:1 under a standard CO adsorption procedure. (Aspect 2) 2. The catalyst composition of claim 1, wherein the inorganic oxide is alumina. (Aspect 3) 3. The catalyst composition of any one of the preceding aspects, wherein the inorganic oxide is doped with a dopant. (Aspect 4) 4. The catalyst composition of aspect 3, wherein the dopant is selected from the group consisting of La, Sr, Si, Ba, Y, Pr, Nd, and Ce. (Aspect 5) 5. The catalyst composition according to aspect 3 or 4, wherein the inorganic oxide has a dopant content of 10% by weight to 30% by weight. (Aspect 6) Aspect 6. The catalyst composition of any one of aspects 3 to 5, wherein the dopant is La. (Aspect 7) Aspect 7. The catalyst composition of any one of aspects 1 to 6, wherein the PGM is Pd. (Aspect 8) 8. The catalyst composition of any one of aspects 1 to 7, further comprising an oxygen storage capacity (OSC) material and / or an alkali metal or alkaline earth metal component. (Aspect 9) Aspect 9. The catalyst composition of any one of aspects 1 to 8, wherein the PGM component is supported on the inorganic oxide. (Aspect 10) 1. A catalyst composition comprising a platinum group metal (PGM) component and an inorganic oxide, wherein the PGM component has an infrared (IR) intensity ratio of CO at gem-dicarbonyl sites to CO at atop sites of less than 5:1 under a standard CO adsorption procedure. (Aspect 11) 11. The catalyst composition of embodiment 10, wherein the inorganic oxide is alumina. (Aspect 12) 12. The catalyst composition of claim 10 or 11, wherein the inorganic oxide is doped with a dopant. (Aspect 13) 13. The catalyst composition of embodiment 12, wherein the dopant is selected from the group consisting of La, Sr, Si, Ba, Y, Pr, Nd, and Ce. (Aspect 14) 14. The catalyst composition according to aspect 12 or 13, wherein the inorganic oxide has a dopant content of 10% by weight to 30% by weight. (Aspect 15) 15. The catalyst composition of any one of aspects 12 to 14, wherein the dopant is La. (Aspect 16) 16. The catalyst composition of any one of aspects 10 to 15, wherein the PGM is Rh. (Aspect 17) 17. The catalyst composition of any one of aspects 10 to 16, further comprising an oxygen storage capacity (OSC) material and / or an alkali metal or alkaline earth metal component. (Aspect 18) 18. The catalyst composition of any one of aspects 10 to 17, wherein the PGM component is supported on the inorganic oxide. (Aspect 19) 1. A catalytic article for treating exhaust gases, comprising: A substrate; a first catalytic region on the substrate; a catalytic article, wherein the first catalytic region comprises a first PGM component and a first inorganic oxide, and wherein the PGM component has an IR intensity ratio of bridge site CO to atop site CO of less than 3:1 under a reference CO adsorption procedure. (Aspect 20) 20. The catalytic article of embodiment 19, wherein the first inorganic oxide is alumina. (Aspect 21) 21. The catalytic article of any one of claims 19 to 20, wherein the first inorganic oxide is doped with a dopant. (Aspect 22) 22. The catalytic article of claim 21, wherein the dopant is selected from the group consisting of La, Sr, Si, Ba, Y, Pr, Nd, and Ce. (Aspect 23) 23. The catalyst article of claim 21 or 22, wherein the dopant content in the alumina is 10% to 30% by weight. (Aspect 24) 24. The catalytic article of any one of aspects 21 to 23, wherein the dopant is La. (Aspect 25) 25. The catalyst article of any one of embodiments 19-24, wherein the first PGM component is Pd. (Aspect 26) 26. The catalytic article of embodiment 25, wherein the first catalytic region is substantially free of PGMs other than Pd. (Aspect 27) 27. The catalytic article of any one of embodiments 19-26, further comprising a first oxygen storage capacity (OSC) material and / or a first alkali metal or alkaline earth metal component. (Aspect 28) 28. The catalyst article of any one of embodiments 19-27, wherein the first PGM component is supported on the first inorganic oxide. (Aspect 29) 29. The catalytic article of any one of embodiments 19-28, further comprising a second catalytic region. (Aspect 30) 30. The catalytic article of embodiment 29, wherein the second catalytic region comprises a second PGM component. (Aspect 31) 31. The catalytic article of embodiment 30, wherein the second PGM component is selected from the group consisting of Pd, Pt, Rh, and mixtures thereof. (Aspect 32) 32. The catalytic article of any one of aspects 29-31, wherein the second catalytic region further comprises a second oxygen storage capacity (OSC) material, a second alkali metal or alkaline earth metal component, and / or a second inorganic oxide. (Aspect 33) Aspect 33. The catalytic article of any one of aspects 29 to 32, wherein the first catalytic region is supported / deposited directly on the substrate. (Aspect 34) 34. The catalytic article of embodiment 33, wherein the second catalytic region is supported / deposited on the first catalytic region. (Aspect 35) 1. A catalytic article for treating exhaust gases, comprising: A substrate; a first catalytic region on the substrate; a catalytic article, wherein the first catalytic region comprises a first PGM component and a first inorganic oxide, wherein the PGM component has an IR intensity ratio of CO at gem-dicarbonyl sites to CO at atop sites of less than 5:1 under a reference CO adsorption procedure. (Aspect 36) 36. The catalytic article of claim 35, wherein the first inorganic oxide is alumina. (Aspect 37) 37. The catalytic article of any one of claims 35 to 36, wherein the first inorganic oxide is doped with a dopant. (Aspect 38) 38. The catalytic article of claim 37, wherein the dopant is selected from the group consisting of La, Sr, Si, Ba, Y, Pr, Nd, and Ce. (Aspect 39) 39. The catalytic article of any one of claims 37 to 38, wherein the dopant content in the alumina is 10% to 30% by weight. (Aspect 40) Aspect 40. The catalytic article of any one of aspects 37 to 39, wherein the dopant is La. (Aspect 41) 41. The catalyst article of any one of embodiments 35-40, wherein the first PGM component is Rh. (Aspect 42) 42. The catalytic article of embodiment 41, wherein the first catalytic region is substantially free of PGMs other than Rh. (Aspect 43) 43. The catalytic article of any one of embodiments 35-42, further comprising a first oxygen storage capacity (OSC) material and / or a first alkali metal or alkaline earth metal component. (Aspect 44) 44. The catalyst article of any one of embodiments 35-43, wherein the first PGM component is supported on the first inorganic oxide. (Aspect 45) 45. The catalytic article of any one of embodiments 35-44, further comprising a second catalytic region. (Aspect 46) 46. ​​The catalytic article of embodiment 45, wherein the second catalytic region comprises a second PGM component. (Aspect 47) 47. The catalytic article of embodiment 46, wherein the second PGM component is selected from the group consisting of Pd, Pt, Rh, and mixtures thereof. (Aspect 48) 48. The catalytic article of any one of aspects 45-47, wherein the second catalytic region further comprises a second oxygen storage capacity (OSC) material, a second alkali metal or alkaline earth metal component, and / or a second inorganic oxide. (Aspect 49) 49. The catalytic article of any one of aspects 45 to 48, wherein the second catalytic region is supported / deposited directly on the substrate. (Aspect 50) 50. The catalytic article of embodiment 49, wherein the first catalytic region is supported / deposited on the second catalytic region. (Aspect 51) 1. A catalytic article for treating exhaust gases, comprising: A substrate; a first catalytic region on the substrate; and a second catalytic region on the substrate; the first catalyst region comprises a first PGM component and a first inorganic oxide; the second catalyst region comprises a second PGM component and a second inorganic oxide; A catalytic article, wherein at least one of the first inorganic oxide and the second inorganic oxide is doped with 10 to 30% of a dopant. (Aspect 52) 52. The catalytic article of claim 51, wherein the dopants for the first inorganic oxide and / or the second inorganic oxide are each independently selected from the group consisting of La, Sr, Si, Ba, Y, Pr, Nd, and Ce. (Aspect 53) 53. The catalytic article of any one of claims 51 to 52, wherein the first inorganic oxide is alumina. (Aspect 54) 54. The catalytic article of any one of aspects 51 to 53, wherein the dopant for the first inorganic oxide is La. (Aspect 55) 55. The catalyst article of any one of aspects 51-54, wherein the first PGM component is Pd. 。 (Aspect 56) 56. The catalyst article of any one of aspects 51-55, wherein the first PGM component has an IR intensity ratio of bridge site CO to atop site CO of less than 3:1 under a reference CO adsorption procedure. (Aspect 57) 57. The catalyst article of any one of aspects 51 to 56, wherein the second inorganic oxide is alumina. (Aspect 58) 58. The catalytic article of any one of aspects 51 to 57, wherein the dopant for the second inorganic oxide is La. (Aspect 59) 59. The catalyst article of any one of embodiments 51-58, wherein the second PGM component is Rh. (Aspect 60) 60. The catalyst article of any one of embodiments 51-59, wherein the second PGM component has an IR intensity ratio of CO at gem-dicarbonyl sites to CO at atop sites of less than 5:1 under a reference CO adsorption procedure. (Aspect 61) An emissions treatment system for treating a combustion exhaust gas stream, comprising the catalytic article of any one of embodiments 19-60. (Aspect 62) A method for treating exhaust gas from an internal combustion engine, comprising contacting the exhaust gas with the catalyst article of any one of aspects 19-60.

Claims

1. 1. A catalytic article for treating exhaust gases, comprising: A substrate; a first catalytic region on the substrate; and a second catalytic region on the substrate; the first catalytic region comprises a first platinum group metal (PGM) component, a first inorganic oxide, and a first oxygen storage capacity (OSC) material, the first platinum group metal (PGM) component being supported on the first inorganic oxide, and the first oxygen storage capacity (OSC) material comprising a ceria-zirconia mixed oxide; the second catalyst region comprises a second platinum group metal (PGM) component, a second inorganic oxide, and a second oxygen storage capacity (OSC) material, the second platinum group metal (PGM) component being supported on the second inorganic oxide, and the second oxygen storage capacity (OSC) material comprising a ceria-zirconia mixed oxide; At least one of the first inorganic oxide and the second inorganic oxide is doped with 10 to 30 wt % of a dopant; the first PGM component is Pd; the dopant for the first inorganic oxide and the second inorganic oxide is each independently La; The catalytic article, wherein the first inorganic oxide and the second inorganic oxide are each independently alumina.

2. The catalytic article of claim 1 , wherein the second PGM component is Rh.

3. 3. The catalytic article of claim 2, wherein the IR intensity ratio of CO at gem-dicarbonyl sites to CO at atop sites in the second PGM component is less than 5:1 under a reference CO adsorption procedure, and the second inorganic oxide is doped with 10 to 30 wt. % of a dopant.

4. An emissions treatment system for treating a combustion exhaust gas stream comprising the catalytic article of any one of claims 1 to 3.

5. A method for treating exhaust gases from an internal combustion engine, comprising contacting said exhaust gases with a catalytic article according to any one of claims 1 to 3.

Images