Patent ID: 8026193

Claim:
An exhaust gas purifying catalyst comprising platinum supported on a metal oxide particle comprising a core part and a surface layer, wherein: a molar fraction of cerium and zirconium constituting a ceria-zirconia solid solution in the core part to all the metals in the core part is higher than a molar fraction of the cerium and zirconium constituting a ceria-zirconia solid solution in the surface layer to all the metals in the surface layer; and a molar fraction of cerium constituting ceria in the surface layer to all the metals in the surface layer is higher than a molar fraction of the cerium constituting the ceria in the core part to all the metals in the core part, wherein said core part and said surface layer each comprises a plurality of primary particles, and the primary particles constituting said core part are particles of ceria-zirconia solid solution.