| 摘要 |
PROBLEM TO BE SOLVED: To provide a catalyst for purifying exhaust gas, which excels in purification efficiency of a cold HC and has good durability, and its manufacturing method. SOLUTION: The exhaust gas purifying catalyst efficiently purifies the cold HC for an internal combustion engine. The catalyst is manufactured by laminating in turn a HC adsorption material layer containing zeolite and silica, and a purifying catalyst component layer containing a noble metal, on a honeycomb carrier. The HC adsorption material layer is formed by coating on aqueous suspension, in which the ratio of an average particle size (Dz) of zeolite after crushing to an average particle size (Ds) of silica sol before crushing is adjusted so as to become Dz/Ds=10-100, on the honeycomb carrier, drying and firing. The HC adsorption material layer is formed by coating the aqueous suspension containing zeolite and silica sol on the honeycomb carrier, flowing air having the temperature in the range of room temperature to 100 deg.C unidirectionally or bidirectionally in a cell extending direction thereby removing moisture, drying by air having the temperature in the range of 100 to 200 deg.C and firing at the temperature in the range of 300 to 500 deg.C. |
