Rhodia Chimie

Rhone-poulenc Chimie

Faurecia Systemes D'echappement

Renault

Thierry Birchem

Olivier Touret

Gilbert Blanchard

Maryline Aubert

Thierry Seguelong

Catherine Hedouin

Christian Sarda

Christophe Bouly

Najat Moral

Thierry Pontier

Christian Bert

Pierre MacAudiere

Marc Guyon

A composition for purifying exhaust gases of an internal combustion engine capable of consuming fuel with lean air-fuel ratios includes elements adsorbing the NOpresent in the exhaust gases, in the presence of excess oxygen and releasing the adsorbed NOwhen the oxygen concentration of the exhaust gases decreases. The NOadsorbing element includes in combination: a first composition comprising a support and an active phase, the active phase being based on manganese and at least another element A selected among, alkalines and alkaline-earths, the manganese and element A being chemically bound; a second composition including a support and an active phase based on manganese and at least another element B selected among alkalines, alkaline-earths and rare earths, the second composition having or being capable of having a specific surface area of at least 80 m/g after being calcined at 800&#xb0; C., and furthermore, a reducing and/or three-way catalyst function is incorporated in the NOadsorbing element.

Purifying composition with NOx treatment and internal combustion engine exhaust gases

A composition based on cerium oxide and on zirconium oxide and, optionally, on a yttrium, scandium or rare-earth metal oxide. The cerium/zirconium atomic proportion is at least 1. The compound exhibits a specific surface, after calcination for 6 hours at 900&deg; C. of at least 35 m,/g and an oxygen storage capacity at 400&deg; C. of at least 1.5 ml of O,/g. The composition is prepared by mixing, in a liquid medium, a cerium compound, a zirconium compound and, if appropriate, a yttrium, scandium or rare-earth metal compound; heating and calcining the precipitate obtained; and using a zirconium solution having an amount of base necessary to reach the equivalent point during an acid/base titration of the solution having a molar ratio of OH,/Zr&lE;1.65. The composition thus obtained is used in the manufacture of multi-functional catalysts.

Composition based on cerium oxide and on zirconium oxide with a high specific surface and a high oxygen storage capacity, process of preparation and use in catalysis

Composition based on zirconium oxide and cerium oxide, preparation method therefor and use thereof

Organic sol comprising at least one oxygenated rare-earth compound,

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Paris, France

Thierry Birchem