Catalyst carrier for exhaust gas and exhaust gas-cleaning catalyst
Provided is a novel catalyst carrier for exhaust gas which relates to an OSC material containing a ceria-zirconia composite oxide and is able to enhance the low temperature properties and to exert excellent OSC even at the time of engine start and excellent exhaust gas purification performance. A catalyst carrier for exhaust gas containing a fluorite type ceria-zirconia composite oxide and ceria formed from the fluorite type ceria-zirconia composite oxide by phase separation proposed.
1. A catalyst carrier for exhaust gas comprising:
a fluorite type ceria-zirconia composite oxide; and
ceria formed from the fluorite type ceria-zirconia composite oxide by phase separation,
wherein a peak area ratio of a diffraction peak at 2θ=28.5° to a diffraction peak between 2θ=29.0 to 30.0° determined from an X-ray diffraction pattern using a CuKα ray obtained by an X-ray diffraction measurement is from 0.05 to 1.00.
2. A catalyst carrier for exhaust gas comprising:
the catalyst carrier for exhaust gas according to claim 1 and a catalyst carrier for exhaust gas containing a pyrochlore type ceria-zirconia composite oxide.
3. The catalyst carrier for exhaust gas according to claim 2 , wherein a mass ratio of a fluorite type ceria-zirconia composite oxide to a pyrochlore type ceria-zirconia composite oxide is from 20:50 to 65:5.
4. A catalyst composition comprising:
Pd; and
the catalyst carrier for exhaust gas according to claim 1 .
5. An exhaust gas purifying catalyst comprising:
a catalyst layer A containing Pt, Rh, or combination thereof; and
a catalyst layer B containing Pd, wherein
at least the catalyst layer B contains the catalyst carrier for exhaust gas according to claim 1 .
6. The exhaust gas purifying catalyst according to claim 5 , wherein Pd is contained at from 0.3 to 8.0% by mass with respect to a total amount of a fluorite type ceria-zirconia composite oxide and ceria formed by phase separation.