| abstract |
A composite oxide and a catalyst for purifying exhaust gas using the same are provided, which oxide has excellent heat resistance, including that a large specific surface area is maintained even when the composite oxide is used in a high temperature environment, and that, even after calcination at 800 °C for 2 hours, no AECeO3 phase is detected and increase in CeO2 crystallite size is inhibited. The composite oxide contains, in terms of oxides, 50 to 98 mass% of a cerium-containing element, the cerium-containing element consisting of Ce and at least one element selected from rare earth elements other than Ce and including Y, Zr, and A1, at 85:15 to 100:0 by mass, 1 to 30 mass% of an alkaline earth metal element, and 1 to 20 mass% silicon in terms of SiO2. |