Composition including a lanthanum perovskite on an alumina or aluminium oxyhydroxide substrate, preparation method and use in catalysis

A technology of aluminum hydroxide and composition, which is applied in the direction of metal/metal oxide/metal hydroxide catalyst, catalyst activation/preparation, manganese compound, etc., can solve the problem of reduced catalytic activity of perovskite and achieve favorable reducibility Effect

Inactive Publication Date: 2012-02-01
RHODIA OPERATIONS SAS
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] Moreover, at high temperatures, the appearance of interfering crystalline phases instead of pure perovskite phases may also be observed
The formation of these phases may lead to the reduction of the catalytic activity of the supported perovskite

Method used

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  • Composition including a lanthanum perovskite on an alumina or aluminium oxyhydroxide substrate, preparation method and use in catalysis
  • Composition including a lanthanum perovskite on an alumina or aluminium oxyhydroxide substrate, preparation method and use in catalysis
  • Composition including a lanthanum perovskite on an alumina or aluminium oxyhydroxide substrate, preparation method and use in catalysis

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0079] This example relates to the preparation of lanthanum-iron-based perovskite (LaFeO 3 ), the carrier contains 6% lanthanum, and the respective ratios (expressed by oxide weight) of perovskite and carrier are 10% and 90%.

[0080] Solutions containing lanthanum-doped alumina and ferrous acetate and lanthanum acetate salts were prepared in advance. For this, 2.26 g of ferrous acetate were diluted in 75 ml of water and 4.46 g of lanthanum acetate were diluted in 75 ml of water. These solutions were mixed and the pH of the mixture thus obtained was 5.4. In addition, the specific surface area will be 180m 2 A dispersion was prepared by dispersing 27 g of doped alumina per gram in 150 ml of water. The ferrous acetate and lanthanum acetate solutions were added to the alumina dispersion to obtain a liquid mixture containing lanthanum-doped alumina and ferrous and lanthanum acetate salts. 11.3 g of 28% NH 4 OH solution was added to the mixture to bring the final pH to 10; pre...

Embodiment 2

[0084] This example relates to the preparation of lanthanum iron perovskite based compositions according to the method of the invention, wherein lanthanum is substoichiometric (La 0.9 FeO 3 ), which is dispersed on the same alumina support as in Example 1, and the respective ratios (expressed by oxide weight) of perovskite and support are 10% and 90%.

[0085]Dilute 2.4g of ferrous acetate in 75ml of water, and 4.25g of lanthanum acetate in 75ml of water. These solutions were mixed and the pH of the mixture thus obtained was 5.5. In addition, a dispersion containing the same amount of alumina as in Example 1 was prepared. The ferrous acetate solution and the lanthanum acetate solution were added to the alumina dispersion. 10 g of sodium hydroxide were then added to the mixture thus obtained to bring the final pH to 10 and the formation of a precipitate was observed. The obtained precipitate was stirred for 1 h30. The precipitate was filtered on a Büchner funnel.

[0086]...

Embodiment 3

[0089] This example relates to the preparation of compositions based on lanthanum iron perovskites doped with cerium and calcium (La 0.9 Ce 0.05 Ca 0.05 FeO 3 ), which is dispersed on the same alumina support as in Example 1, and the respective ratios (expressed by oxide weight) of perovskite and support are 10% and 90%.

[0090] On the one hand, 4.09g of lanthanum acetate, 0.22g of cerium acetate and 0.11g of calcium acetate were diluted in 75ml of water; on the other hand, 2.31g of ferrous acetate was diluted in 75ml of water. These solutions were mixed to obtain an acetate mixture with a pH of 5.5. In addition, a dispersion containing the same amount of alumina as in Example 1 was prepared. A solution of ferrous acetate, cerium acetate, calcium acetate and lanthanum acetate was added to the alumina dispersion. 14 g of sodium hydroxide were then added to the mixture thus obtained to bring the final pH to 10 and the formation of a precipitate was observed. The obtained ...

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Abstract

The composition according to the invention includes a perovskite of the formula LaMO3, where M is at least one element selected from among iron, aluminium or manganese, in the form of particles dispersed on an alumina or aluminium oxyhydroxide substrate, characterised in that after calcination at 700 C for 4 hours, the perovskite is in the form of a pure crystallographic phase, and in that the size of the perovskite particles does not exceed 15 nm. The composition according to the invention can be used in the field of catalysis.

Description

technical field [0001] The present invention relates to a composition containing lanthanum-based perovskite on a carrier made of alumina or aluminum oxyhydroxide, to a process for its preparation and to its catalytic use. Background technique [0002] The known general formula is ABO 3 Perovskites show favorable properties in the field of catalysis. In this field it is preferred that they are used in supported form in order to increase the contact surface area between the perovskite and the stream to be treated (eg gas). The support may especially be alumina, silica or ceria. [0003] In the case of carrier-supported perovskites, it is important that the perovskite is dispersed on the carrier as finely as possible; that is to say it is provided on the carrier in the form of fine particles of nanometer size. Furthermore, since the catalysts are often exposed to high temperatures, it is prudent to maintain the finely divided state of the perovskite even at these temperature...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J23/00
CPCB01J23/002Y02C20/10B82Y30/00C01G49/0054C04B2235/3229B01J2523/00C01G45/1264C04B2235/3227B01J23/34C04B35/2675C01P2002/72C01P2002/34B01J37/031C01P2004/64C04B2235/3208B01J23/10B01J35/006B01J23/83B01J2523/3706B01J2523/842B01J2523/72B01J2523/23B01J2523/3712B01J37/08C04B35/50B01J21/04B01J35/026
Inventor S·伊弗拉O·拉尔谢R·乔治科伊尔霍马奎斯M·拉勒芒J·埃尔南德兹
Owner RHODIA OPERATIONS SAS
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