CATALYST FOR DECOMPOSITION OF NITROGEN OXIDE AND METHOD FOR REMOVING NITROGEN OXIDE IN EXHAUST GAS FROM DIESEL ENGINE BY USING THE SAME

摘要

PURPOSE: To decrease NO_x and to burn and remove carbonaceous particulates, unburned hydrocarbon and carbon monoxide or the like, by using a catalyst for decomposition of nitrogen oxide, made by combining a catalyst layer containing platinum and a catalyst layer containing copper. ;CONSTITUTION: At first, a refractory inorganic oxide powder carrying platinum is formed by making carry a catalytically active oxide of at least one metal selected from the group consisting of tungsten, antimony, molybdenum, nickel, vanadium, manganese, iron, bismuth, cobalt, zinc and alkaline earth metals together with platinum into a 1st refractory inorganic oxide powder. A 1st catalytic composition consisting of the refractory inorganic oxide powder carrying platinum and the 2nd refractory inorganic oxide powder is coated on a refractory three dimensional structure. Thus, the catalyst for decomposing nitrogen oxide is obtained by applying coating of a 2nd catalytic composition carrying copper and rhodium to a 3rd refractory inorganic oxide powder onto the layer carrying a catalytic component thus formed. This catalyst suppresses a particulate substance and is excellent in durability at high temperatures.;COPYRIGHT: (C)1996,JPO