| 摘要 |
PURPOSE: To effectively reduce and remove a nitrogen oxide from combustion exhaust gas containing nitrogen oxide and excessive oxygen by providing a first catalyst, a second catalyst carrying the amount of more carrying rate of active species of the first catalyst and a third catalyst having different active species in order successively starting from the inflow side to the outflow side of a purifying material. CONSTITUTION: An exhaust gas purifying material contains a first catalyst carrying silver and/or a silver compound or a mixture of them of 0.1-12wt.% (silver element conversion value) as active species on a porous inorganic oxygen. It also cantinas a second catalyst carrying silver and/or a silver compound or a mixture of them of 1-15wt.% (silver element conversion value) as active species and also carrying active species of the amount more than the carrying rate of the active species of the first catalyst. It also contains a third catalyst as active species carrying at least an oxide of one kind of element selected out of a group composed of W, V, Mo, Mn, Nb and Ta as active species of 0.5-30wt.% (metal element conversion value). |
