Precise composition/kinetic characterization of solid catalysts using temporal analysis of products

Abstract

The kinetic properties of a heterogeneous catalyst are markedly influenced by the surface composition of the catalyst itself as well as the composition of adsorbed species. The complex nature of an industrial catalyst surface creates a challenge for directly addressing the composition/kinetics relationship. The TAP (Temporal Analysis of Products) methodology is presented as a unique tool using gas pulsing for systematic control of catalyst composition that at the same time provides precise kinetic characterization. The technique is compared to more commonly used kinetic tools such as the continuous stirred tank reactor and plug flow reactor for collecting kinetic data. Theoretical methods for the analysis of exit flux temporal data are discussed along with more recently developed methods for calculation of time dependent rate and concentration profiles. To highlight the utility of the tool for addressing the composition/kinetics relationship, experimental examples are presented that demonstrate surface coverage changes within one pulse response, surface evolution over the course of a multipulse sequence and changes in the context of pump/probe dynamics.