PURPOSE: To prolong the service life of catalyst and prevent self vibration by eliminating the presence of activators from at least one flow passage out of flow passages which adjoin flow passages having activators which cause catalytic reaction out of honeycomb fluid flow passages.
CONSTITUTION: Zirconia alumina composite oxide particles are submerged in a palladium nitrate aqueous solution and dried and then burned. A binder is added to the particles thus obtained so as to produce a slurry. A honeycomb cordierite base material is coated with the slurry and burned, thereby adjusting a catalyst. The coating quantity of an apparent cordierite base material per surface area is adapted to be identical and controlled so that the base material is classified into a substance where cells 1 are alternately coated with activators 2 and an activator-coated substance designed to eliminate the presence of the activators 2 at least in one cell 1 out of the cells which adjoin the cells 1 having activator. The result of methane combustion test indicates that there exists no vibration phenomenon in either case and the burning rate and the outlet temperature of a catalyst layer are fixed as well.
SAKAI MASAYASU
IMAI TETSUYA
