Patent ID: 9376327
Filing Date: 2016-06-28
CPC Classification: B01J,C01G,C01P,C04B

Claim Text:
1. A ceria-zirconia base composite oxide comprising a composite oxide of ceria and zirconia, wherein a content ratio between cerium and zirconium in the composite oxide is in a range from 43:57 to 48:52 in terms of molar ratio ([cerium]:[zirconium]), an average value (number-based average value) of diameters of crystal grains is 2.2 to 4.5 μm in a field of view (magnification 500×) of a scanning electron microscope, and an intensity ratio of a diffraction line at 2θ=14.5° to a diffraction line at 2θ=29° {I(14/29) value} and an intensity ratio of a diffraction line at 2θ=28.5° to the diffraction line at 2θ=29° {I(28/29) value}, which are calculated from an X-ray diffraction pattern obtained by an X-ray diffraction measurement using CuKα after heating under a temperature condition of 1100° C. in air for 5 hours, respectively satisfy the following conditions: I(14/29) value≧0.015, and I(28/29) value≦0.08.