US Patent 7723259 Particulate matter (PM) oxidizing catalyst

A particulate matter oxidizing catalyst includes: at least one metal selected from the group consisting of: gallium, manganese, iron, cobalt, nickel, copper, yttrium, zirconium, niobium, molybdenum, silver, lanthanum, praseodymium, neodymium and gold; and cerium, wherein a first oxide includes: the cerium, and a first metal which is at least one element selected from the group consisting of: gallium, manganese, iron, cobalt and nickel, wherein a second oxide includes: the cerium, and a second metal which is at least one element selected from the group consisting of: praseodymium, zirconium and aluminum, and wherein the second oxide and the first oxide have a content ratio of second oxide/(first oxide+second oxide)=0.1 by mass to 0.8 by mass.