| Further development in automotive catalyst performance is needed to meet increasingly stringent government emission standards. A thorough understanding is required of the relationship between reaction parameters and catalyst components that influences activity, especially of short-chain alkanes, which are oxidized more slowly than other hydrocarbons (HC's). The catalysts consisted of a precious metal (platinum or palladium) supported on a conventional support (;At high metal loadings, the oxidation rate was the same over all three supports. A comparison of highly dispersed platinum and palladium, where the support effect is maximized, showed an activity decrease in the order Pt/zirconia ;Sulfur dioxide can react with the catalyst to form surface sulfate and was identified on ;To summarize, the propane-oxidation rate was increased for platinum at high metal loadings on ;This thesis has demonstrated that the choice of precious metal, particle size and support material coupled with a knowledge of the interaction between the catalyst and other exhaust components, such as sulfur, are of paramount importance for the development of high performance catalysts. |
