INORGANIC MIXED OXIDE AND EXHAUST GAS PURIFICATION CATALYST USING THE SAME

文件类型：PDF文档
文件大小：276K
PROBLEM TO BE SOLVED : To provide an inorganic mixed oxide which has excellent heat resistance and, when used as a carrier of a catalyst, is capable of allowing the catalyst to exhibit high oxygen storage performance, high HC reforming activity and high NOx removal performance in a well-balanced state. SOLUTION : The particulate inorganic mixed oxide contains aluminum, zirconium, cerium, and the first and second additional elements which are selected from the group consisting of rare earth elements except cerium and the group consisting of alkaline earth elements, respectively, wherein the content of aluminum in the inorganic mixed oxide is 60-90 at.% in terms of element based on the total amount of elements which are converted into cations in the inorganic mixed oxide; the content of cerium in the inorganic mixed oxide is 0.4-50 at.% in terms of element based on the total amount of zirconium and cerium contained in the inorganic mixed oxide; the total content of the first and second additional elements is 1-12 at.% in terms of element based on the total amount of elements which are converted into cations in the inorganic mixed oxide; at least 80% of the primary particles of the inorganic mixed oxide have particle diameters of ≤100 nm; at least part of the primary particles have, on the surfaces, enriched areas wherein the content of the second additional element is locally enhanced; and the amount of the second additional element contained in the enriched areas is 0.1-0.95 mass% in terms of oxide based on the total amount of the inorganic mixed oxide. COPYRIGHT : (C)2009, JPO&INPIT