In the preceding paper the specific heat capacity, substrate heat capacity, and energy requirements of two types of substrates were discussed in detail both from the standpoint of predictions from measured material property values as well as actual energy measurements on ceramic and metal products. This information is valuable for the catalyst designer because of the light-off impact of this energy requirement. Some material was also presented regarding the change in this energy requirement with washcoat loading. Other aspects of the substrate which could reasonably come into play to enhance the light-off characteristics of a catalyst are the rates of heat and mass transfer. The latter of these could reasonably be expected to drive the catalyst activity.
