Composition containing oxides of zirconium, cerium and another rare earth having reduced maximal reducibility temperature, and method for preparing and using same in the field of catalysis

A technology of rare earth elements and cerium oxides, applied in the direction of metal/metal oxide/metal hydroxide catalysts, rare earth metal oxides/hydroxides, lanthanide oxides/hydroxides, etc., can solve low-ratio surface area, difficulty in reconciliation, etc.

Active Publication Date: 2012-11-21
RHODIA OPERATIONS SAS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] However, it can be seen from the prior art that these two properties are usually difficult to reconcile, that is, high reducibility at lower temperatures corresponds to a rather low specific surface area

Method used

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  • Composition containing oxides of zirconium, cerium and another rare earth having reduced maximal reducibility temperature, and method for preparing and using same in the field of catalysis
  • Composition containing oxides of zirconium, cerium and another rare earth having reduced maximal reducibility temperature, and method for preparing and using same in the field of catalysis
  • Composition containing oxides of zirconium, cerium and another rare earth having reduced maximal reducibility temperature, and method for preparing and using same in the field of catalysis

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0095] This example relates to a composition having 50% zirconium, 40% cerium, 5% lanthanum and 5% yttrium, the proportions being expressed as the oxide ZrO 2 , CeO 2 , La 2 o 3 and Y 2 o 3 expressed as a mass percentage.

[0096] The required amounts of zirconium nitrate, cerium nitrate, lanthanum nitrate, and yttrium nitrate were introduced into the stirred beaker. It is then topped up with distilled water to obtain 1 liter of a 120 g / l nitrate solution.

[0097] Ammonia solution (12 mol / l) was added to another stirred beaker and then made up with distilled water to obtain a total volume of 1 liter, and a 20% stoichiometric excess of ammonia relative to the cation to be precipitated.

[0098] The two pre-prepared solutions were kept under constant stirring and were continuously added to figure 1 In a Hartridge-Roughton flash mixer of the type shown, the inlet height (a) is 2mm. The pH on leaving the mixer was 9.5. The flow rate of each reactant was 30 l / h and the re...

Embodiment 3

[0108] This example concerns the same composition as in Example 1, prepared under the same conditions, with the only difference that the initial ammonia solution was prepared with a 5% stoichiometric excess of ammonia relative to the cation to be precipitated.

Embodiment 4

[0110] This example relates to a composition having 72% zirconium, 21% cerium, 2% lanthanum and 5% neodymium, the proportions being expressed as the oxide ZrO 2 , CeO 2 , La 2 o 3 and Nd 2 o 3 expressed as a mass percentage.

[0111] The required amounts of zirconium nitrate, cerium nitrate, lanthanum nitrate, and neodymium nitrate were introduced into the stirred beaker. It is then topped up with distilled water to obtain 1 liter of a 120 g / l nitrate solution.

[0112] Ammonia solution (12 mol / l) was added to another stirred beaker and then made up with distilled water to obtain a total volume of 1 liter, and a stoichiometric excess of ammonia of 20% relative to the cation to be precipitated.

[0113] The two pre-prepared solutions were kept under constant stirring and were continuously added to figure 1 In a Hartridge-Roughton flash mixer of the type shown, the inlet height (a) is 2mm. The pH on leaving the mixer was 9.6. The flow rate of each reactant was 50 l / h an...

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Abstract

The invention relates to a composition containing oxides of zirconium, cerium and another rare earth different from cerium, having a cerium oxide content not exceeding 50 wt% and, after calcination at 1000 DEG C for 6 hours, a maximal reducibility temperature not exceeding 500 DEG C and a specific surface of at least 45 m2/g. The composition is prepared according to a method that comprises continuously reacting a mixture containing compounds of zirconium, cerium and another rare earth having a basic compound for a residence time not exceeding 100 milliseconds, wherein the precipitate is heated and contacted with a surfactant before calcination.

Description

technical field [0001] The present invention relates to a composition based on oxides of zirconium, cerium and at least one rare earth element other than cerium having a high reducibility maximum temperature, a process for its preparation and its use in the field of catalysts. Background technique [0002] So-called "multifunctional" catalysts are currently used for exhaust gas treatment of internal combustion engines (automotive afterburning catalysis). The term "multifunctional" is understood to mean catalysts capable of not only oxidation of especially carbon monoxide and hydrocarbons present in exhaust gases, but also reduction of especially nitrogen oxides also present in these exhaust gases ("three-way" catalyst). Products based on oxides of zirconium, cerium and one or more oxides of rare earth elements other than cerium are currently considered to be particularly important and advantageous components to include in the composition of such catalysts. To be efficient,...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01G25/00B01D53/94B01J21/06B01J23/10C01G25/02B01D53/00C01F17/00
CPCB01D2255/2061B01J37/009B01J23/10C01P2006/32B01D53/8612B01D53/944B01J35/023B01D2255/2066C01G25/02C01P2002/50B01J37/031B01J35/1014B01D2255/2063C01P2002/88C01P2006/13B01J37/038B01D53/8603B01D2255/407B01D53/94B01J21/066C01P2004/62B01D2255/2068C01G25/00C01F17/235C01F17/229C01F17/218C01F17/206C01B13/363B01J35/1004B01J37/08C01P2006/12B01D2255/2065
Inventor S·伊弗拉E·罗阿尔J·埃尔南德兹S·德奈勒
Owner RHODIA OPERATIONS SAS
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