| 摘要 |
PURPOSE: To efficiently reduce and remove nitrogen oxide by using first - third catalysts obtained by respectively supporting specific elements and/or compds. on porous inorg. oxide carriers. CONSTITUTION: A first catalyst is obtained by supporting 0.2-15wt.% (in terms of a silver element) of one element and/or a compd. selected from silver and a silver compd. on porous inorg. oxide, and a second catalyst is obtained by supporting 0.01-10wt.% (in terms of a metal element) of a compd. of at least one element selected from a group consisting of W, V, Mo, Mn, Nb and Ta on porous inorg. oxide, and a third catalyst is obtained by supporting 0.5-30wt.% (in terms of a metal element) of one element selected from a group consisting of silver, copper and nickel as an active seed and/or a compd. thereof on porous inorg. oxide. The mixed catalyst of the first and second catalysts is provided on the exhaust gas inflow side of an exhaust gas purifying material and the third catalyst is provided on the outflow side thereof. By this constitution, nitrogen oxide in exhaust gas containing oxygen in a theoretical reaction amt. or more can be efficiently removed. |
