| 摘要 |
PROBLEM TO BE SOLVED: To enable a process in which a catalyst is obtained for purifying NOx effectively without wasting an HC reducing agent, and especially the purification capacity of the catalyst in a higher temperature range is improved remarkably. SOLUTION: This method includes one or more powder making processes in which a mixture of zeolite powder and an active metal salt aqueous solution is agitated and dried into powder and a heat treatment process in which the powder is burned or heat-treated under a controlled atmosphere of inert gas, reducing gas, or SO2 gas which is prepared in accordance with the raw material active metal salt. Especially when one or more kinds of active metals including Co are used, the powder is treated under the controlled atmosphere to check the generation of Co3 O4 . |
