COMPOSITE OXIDE, METHOD FOR PRODUCING SAME AND CATALYST FOR EXHAUST GAS PURIFICATION

FIELD : chemistry. SUBSTANCE : invention discloses a complex oxide comprising 60–98 % by weight of cerium oxides and at least one element selected from the group consisting of rare earth metals other than cerium, and including yttrium, zirconium and silicon at a rate of 85 : 15 to 100 : 0 by weight; 1–20 % by weight of an alkaline earth metal oxide and 1–20 % by weight of Al2O3, where after calcination at 800 °C for 2 hours, said complex oxide has a specific surface area of at least 40 m2/g when measured by the BET method, does not contain the AECeO3 phase (where AE is an alkaline earth metal element) and has a CeO2 crystallite size in the (111) plane a not more than 15 nm, as determined using the X-ray diffraction. Also disclosed is a process for the said complex oxide preparation and a exhaust gas purifying catalyst containing a complex oxide. EFFECT : technical result consists in obtaining a car exhaust gas purifying catalyst that reduces or removes NOx and has excellent heat resistance. 9 cl, 1 tbl, 13 ex