COMPOSITION BASED ON ZIRCONIUM OXIDE AND CERIUM OXIDE, WITH A HIGH REPRODUCIBILITY AND A STABLE SPECIFIC SURFACE AREA, METHOD OF PREPARATION AND USE IN THE TREATMENT OF EXHAUST GASES

Catalyst compositions for the treatment of vehicular exhaust gases are based on zirconium and cerium oxides, have a cerium oxide content of at most 50% by weight, a level of reducibility of at least 95% after calcination in air at 600°, and a specific surface area after calcination for 4 hours at 11...

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Bibliographische Detailangaben
Hauptverfasser:	LARCHER, Olivier, PACAUD, Bernard, SUDA, Eisaku, TAKEMORI, Hirofumi, VERDIER, Stephan, ROHART, Emmanuel
Format:	Patent
Sprache:	eng ; fre ; ger
Schlagworte:	CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY CHEMISTRY COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSESC01D OR C01F INORGANIC CHEMISTRY METALLURGY PERFORMING OPERATIONS PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL SEPARATION THEIR RELEVANT APPARATUS TRANSPORTING
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Beschreibung
Zusammenfassung:	Catalyst compositions for the treatment of vehicular exhaust gases are based on zirconium and cerium oxides, have a cerium oxide content of at most 50% by weight, a level of reducibility of at least 95% after calcination in air at 600°, and a specific surface area after calcination for 4 hours at 1100° of at least 15 m2/g; such compositions are prepared by forming an aqueous mixture containing zirconium and cerium compounds, by heating this mixture to at least 100° and, after the heating, adjusting it to a basic pH, by adding a surfactant additive to the precipitate obtained from this mixture and by calcinating the precipitate in an inert gas or under vacuum at a temperature of at least 900° and then in an oxidizing atmosphere at a temperature of at least 600°.