Precise non-steady-state characterization of solid active materials with no preliminary mechanistic assumptions

This paper presents a straightforward procedure for non-steady-state kinetic characterization of solid active materials, particularly catalysts, by extracting quantities called reactivities which are obtained from pulse-response data using the Temporal Analysis of Products (TAP) methodology. This method provides a new 'state characterization' of materials to understand their physicokinetic behavior and does not require knowledge of mechanism. In this paper, three reactivities are presented as explicit functions of pulse response data and then the numerical values of reactivities are calculated from experimental moment data of pulse response curves. Two procedures based on the availability and reliability of reactant and product data are distinguished here. The developed theoretical procedure is illustrated by the experimental example of CO oxidation over a supported Au/SiO2 catalyst pretreated with oxygen. We consider the presented procedure as an efficient tool for precise non-steady-state kinetic characterization of many active materials, e.g. catalysts, adsorbents, sensors, electrodes etc.