EXHAUST GAS PURIFYING MATERIAL AND METHOD

PURPOSE:To efficiently purify oxygen excessive combustion exhaust gas by using a first catalyst wherein silver, W or V and platinum components are supported on porous inorg. oxide and a second catalyst having a platinum component supported thereon. CONSTITUTION:0.2-15wt.% of silver or silver oxide, 0.01-10wt.% of oxide of an element such as W, V or Mn and 1wt.% or less of an element such as Pt or Pd are supported on porous inorg. oxide to obtain a first catalyst while 5wt.% or less of an element such as Pt or Pd is supported on porous inorg. oxide to obtain a second catalyst. Two catalysts are combined to be used not only to efficiently remove nitrogen oxide from combustion exhaust gas containing oxygen in an amt. equal to or more than a theoretical reaction amt. with respect to a non-combustion component such as nitrogen oxide or carbon monoxide but also to remove residual unreacted carbon monoxide or hydrocarbon by oxidation.