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

摘要

Provided are: a complex oxide that exhibits high redox ability even at low temperatures, has excellent heat resistance, and stably retains these characteristics even on repeated oxidation and reduction at high temperature; a method for producing the same; and an exhaust gas purification catalyst. The inventive complex oxide contains Ce; rare earth metal element other than Ce, including Y; Al and/or Zr; and Si; such that the Ce, and said other elements other than Ce and Si, are present in a mass ratio of 85:15-99:1, calculated as oxides; and has a characteristic such that when it is subjected to temperature-programmed reduction (TPR) measurement in a 10% hydrogen-90% argon atmosphere at from 50° C. to 900° C. with the temperature increasing at a rate of 10° C./min, followed by oxidation treatment at 500° C. for 0.5 hours, and then temperature-programmed reduction measurement is performed again, its calculated reduction rate at and below 400° C. is at least 2.0%.

主权项

1. A complex oxide containing:
cerium; at least one rare earth metal element other than cerium; at least one element selected from aluminum and zirconium; and silicon;such that the cerium, and said other elements other than cerium and silicon, are present in a mass ratio of between 85:15 and 99:1, calculated as oxides; wherein the complex oxide has, subsequent to reduction in a 10% hydrogen-90% argon atmosphere between 50° C. and 900° C. with temperature increasing at 10° C/min, followed by oxidation at 500° C. for 0.5 hours, a reduction rate at and below 400° C. of at least 2.0% as measured by temperature-programmed reduction (TPR) in a 10% hydrogen-90% argon atmosphere between 50° C. and 900° C. with temperature increasing at 10° C/min.