It should be common sense to be concerned for reducing amount of platinum group metals, usage in three-way catalyst over keeping its performance due to tough atmosphere for catalytic reactions. From recent study of thermal deterioration in both palladium catalyst and rhodium one, following were found: 1) PdO should be key to avoid Pd sintering and uniformly dispersed barium on alumina is effective to maintain PdO phase. 2) To disperse Pd particle in 3-dimentional nano-structure by porous alumina has also big impact on inhibition of Pd sintering. 3) The encapsulated structure of cerium-zirconium-Rh by lanthanum-alumina leads to suppress Rh sintering.