MOMENT-BASED ANALYSIS OF TRANSIENT-RESPONSE CATALYTIC STUDIES (TAP EXPERIMENT)

A new moment-based theoretical approach for the analysis of TAP (tempo ral analysis of products) pulse-response data is described. The distin guishing feature of this approach is that the variables of the set of ordinary differential equations that comprise the model are moments in stead of concentrations. The moments are functions of the reactor axia l coordinate, whereas concentrations are functions of space and time. The theoretical framework for the extraction of kinetic parameters usi ng this approach is developed, and is used to determine kinetic parame ters for CO oxidation over platinum powder. A new phenomenon, called ' 'TAP equilibrium'' is described. This phenomenon is governed by the in terplay between reaction and Knudsen diffusion.