| 摘要 |
PROBLEM TO BE SOLVED: To improve the efficiency of removing NOx by incorporating a zeolite which carries at least one kind of group VIII metal and a refractory inorg. oxide which carries barium to prepare a catalyst for purifying an exhaust gas which can purify NOx in an exhaust gas containing sulfur oxides especially in an oxygen-rich atmosphere. SOLUTION: Since NOx exhausted from an internal combustion engine is present in an oxygen-rich atmosphere, it can not be sufficiently purified by a ternary catalyst. The purifying catalyst for an exhaust gas which removes NOx even in an oxygen-rich atmosphere is prepared from a zeolite carrying at least one kind of group VIII metal (Fe, Co, Ni, Ru, Rh) and a refractory inorg. oxide carrying barium. The zeolite catalyst carrying group VIII metals is preferably produced by depositing group VIII metals on the zeolite by ion exchanging method. As for the zeolite used, a zeolite having high activity after ion-exchanged with group VIII metal and having excellent durability is preferable, and for example, pentacyl zeolite or the like is preferable. |
