COMPOSITION BASED ON ZIRCONIUM, CERIUM, LANTHAN AND YTTRIUM OXIDES, GADOLINIUM OR SAMARIUM, WITH STABLE SPECIFIC SURFACE, PROCESS FOR PREPARATION AND USE AS CATALYST

摘要

Composition (A) comprising zirconium oxide, cerium oxide, lanthanum oxide and oxide of another rare earth e.g. yttrium, samarium and gadolinium, presents a specific surface of =40 m 2/g after calcination for 4 hours at 1000[deg]C, a specific surface of =15 m 2/g after calcination for 10 hours at 1150[deg]C, a specific surface of =7 m 2/g after calcination for 10 hours at 1200[deg]C and a content of lanthanum oxide and oxide of other rare earth metals at =15%. Independent claims are included for: (1) preparation of (A) comprising preparing a mixture in a liquid medium containing zirconium, cerium, lanthanum and other rare earth compounds, contacting the mixture with basic compound to obtain a precipitate, heating the precipitate in a liquid medium, adding additives such as to the obtained precipitate anionic surfactants, non-ionic surfactants, polyethyleneglycols, carboxylic acids and their salts or ethoxylate type surfactant of fatty carboxymethyl alcohols, washing the obtained precipitate and calcining the obtained precipitate; (2) a catalytic system, comprising (A); and (3) treatment of exhaust gases from internal combustion engines, using the catalytic system.