| 摘要 |
PROBLEM TO BE SOLVED: To provide the production of a catalyst composition having excellent properties with respect to platinum group metal dispersion. SOLUTION: This production of a catalyst composition comprises a stage (a) for dispersing at least one platinum group metal catalyst component on activated alumna and a stage (b) for coating a carrier base body with the resulting activated alumina having the platinum group metal catalyst component on it and calcining the formed coating material on the carrier base body, where the stages (a) and (b) are performed under restricted acidifying conditions to allow at least one of platinum, rhodium and palladium catalyst components to exist in the composition and to produce the objective catalyst composition on the carrier base body. At this time, the degree of dispersion of each of these platinum group metal catalyst components on the activated alumina is maintained at about >=0.3CO/PM (number of carbon monoxide molecules adsorbed on one atom of the platinum group metal), wherein the measurement of the degree of dispersion is performed by using a catalyst composition sample treated as follows: (1) when the catalyst component metals(s) is platinum and/or rhodium, the sample is reduced in gaseous hydrogen at 750 deg.C for 1hr; or (2) when the catalyst component metal is palladium, the sample is heated in air at 750 deg.C for 1hr and then, reduced in gaseous hydrogen at 350 deg.C for 1hr. |
