Catalyst for gasoline lean burn engines with improved no oxidation activity

A catalyst and catalyst coating technology, which is applied in combustion engines, internal combustion piston engines, metal/metal oxide/metal hydroxide catalysts, etc., can solve the problem of poor coordination between oxidation activity and NO oxidation activity, strong loss of catalytic activity, etc. problem, to achieve the effect of improving NO oxidation activity

Active Publication Date: 2013-07-03
BASF AG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] This problem exists in exhaust gas treatment systems for the treatment of nitrogen oxides, especially in exhaust gases from lean burn systems with air:fuel ratios of 20:1 or higher: hydrocarbons (HC ) oxidation activity and NO oxidation activity remain poor after aging (i.e. after durability test)
This sintering process is accompanied by a strong loss of catalytic activity for hydrocarbon oxidation and especially NO oxidation on prior art TWC converters

Method used

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  • Catalyst for gasoline lean burn engines with improved no oxidation activity
  • Catalyst for gasoline lean burn engines with improved no oxidation activity
  • Catalyst for gasoline lean burn engines with improved no oxidation activity

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0092] (inner layer)

[0093] Platinum in the form of a platinum tetramethylammonium hydroxide complex solution and subsequently palladium in the form of a palladium nitrate solution was impregnated with a high surface area doped with 0.4% lanthanum oxide and 15% zirconia by means of a planetary mixer (P-mixer). Gamma alumina to form a wet powder while achieving incipient wetness. The amount of Pt and Pd is chosen to achieve 10 g / ft in the catalyst layer 3 Pt and 2g / ft 3 Final concentration of Pd.

[0094] Then by adding Pt and Pd supported high surface area gamma alumina, ceria, zirconia, baria, magnesia and binder at about 33%, 44%, 3%, 11.5%, respectively based on the calcined weight of the catalyst. Concentrations of 7% and 1% combine to form an aqueous slurry with water. Zirconia was introduced as an acetate colloidal solution and barium oxide as a barium acetate solution. The resulting slurry was then ground to a 90% particle size of less than 10 μm.

[0095] The s...

Embodiment 2

[0105] (inner layer)

[0106] Platinum in the form of a platinum tetramethylammonium hydroxide complex solution and subsequently palladium in the form of a palladium nitrate solution was impregnated with a high surface area doped with 0.4% lanthanum oxide and 15% zirconia by means of a planetary mixer (P-mixer). Gamma alumina to form a wet powder while achieving incipient wetness. The amount of Pt and Pd is chosen to achieve 10 g / ft in the catalyst layer 3 Pt and 2g / ft 3 Final concentration of Pd.

[0107] Then by adding Pt and Pd supported high surface area gamma alumina, ceria, zirconia, baria, magnesia and binder at about 54%, 30%, 3%, 7%, respectively based on the calcined weight of the catalyst. Concentrations of 7% and 1% combine to form an aqueous slurry with water. Zirconia was introduced as an acetate colloidal solution and barium oxide as a barium acetate solution. The resulting slurry was then ground to a 90% particle size of less than 10 μm.

[0108] The slur...

Embodiment 3

[0118] The catalyst of Example 3 was prepared according to the procedure of Example 2, wherein to prepare the inner layer, high surface area gamma alumina doped with 0.4% lanthanum oxide and 15% zirconium oxide was loaded with Pt and Pd to achieve 13 g / m in the inner layer of the catalyst. ft 3 Pt and 3g / ft 3 Final concentration of Pd. The components present in the inner layer are Pt and Pd supported high surface area gamma alumina, ceria, Zirconia, barium oxide, magnesium oxide and binders. The total load of the inner layer is 2g / in3 .

[0119] To prepare the interlayer, high surface area gamma alumina doped with 0.4% lanthanum oxide and 15% zirconia was loaded with Pt and Pd to achieve 31 g / ft in the catalyst interlayer 3 Pt and 5g / ft 3 Final concentration of Pd. The components present in the interlayer are Pt and Pd supported high surface area gamma alumina, ceria, Zirconia, barium oxide, magnesium oxide and binders. The total load of the middle layer is 2.2g / in 3 ...

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Abstract

The present invention relates to a catalyst comprising a substrate and a catalyst coating, the catalyst coating comprising two or more layers, said layers comprising: (a) a first layer provided on the substrate, said first layer comprising Pt and / or Pd; and (b) a second layer provided on the first layer, said second layer comprising Pt; the first and second layers each further comprising: one or more particulate support materials; one or more oxygen storage component (OSC) materials; and one or more nitrogen oxide storage materials comprising one or more elements selected from the group of alkali and / or alkaline earth metals, wherein the total amount of alkali and alkaline earth metals comprised in the one or more nitrogen oxide storage materials contained in the catalyst ranges from 0.18 to 2.5 g / in calculated as the respective alkali metal oxides M 2 O and alkaline earth metal oxides MO, as well as to a method for the production of a catalyst, and to a process for the treatment of a gas stream comprising nitrogen oxide, in particular of an exhaust gas stream resulting from an internal combustion engine.

Description

technical field [0001] The present invention relates to catalysts having improved NO oxidation activity, as well as methods and systems for treating automotive exhaust gas streams. In particular, the present invention relates to three-way catalysts (TWC) that can be used with selective catalytic reduction (SCR) catalysts. Background technique [0002] One of the problems encountered in the treatment of automotive exhaust, especially from lean-burn engines such as diesel exhaust and lean-burn gasoline engines, concerns the treatment of nitrogen oxides contained therein. To this end, many exhaust gas treatment systems used in automobiles operating under lean burn conditions incorporate a combination of NOx storage catalysts located upstream of the SCR catalyst. In particular, nitrogen oxides contained in the exhaust gas stream are stored at lower temperatures in the NOx storage catalyst for release at higher operating temperatures where their efficient reduction can be achiev...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J23/40B01J37/025B01D53/94
CPCB01D53/945B01D2255/1021B01D2255/1023B01D2255/1025B01D2255/2022B01D2255/2025B01D2255/2027B01D2255/2042B01D2255/2045B01D2255/2047B01D2255/2063B01D2255/2065B01D2255/2066B01D2255/2068B01D2255/20715B01D2255/9032B01D2255/908B01D2255/911B01D2258/014B01J21/04B01J21/066B01J23/40B01J23/464B01J23/58B01J23/63B01J37/0036B01J37/0201B01J37/0244B01J37/038Y02A50/20Y02T10/12B01J37/02B01D53/94
Inventor M·希尔真多夫
Owner BASF AG
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