(429g) Every Transient Tells a Story

In this talk we relate four "Scientific Moments" from research using the Temporal Analysis of Products (TAP) reactor system performed over a period spanning forty plus years. "Scientific Moments" refers to unexpected, surprising, and in some cases almost unbelievable experimental results. The talk begins with a brief description of the key components of a TAP system, lists the large menu of experiments that can be performed at vacuum and high pressures, and illustrates how the system can be quickly cycled between pressure regimes.

In a TAP pulse response experiment gas transport through a particle bed is well defined and can be used as a "measuring stick" in the determination of kinetic parameters. An inert gas is used to obtain the transport-only response, which is determined by Knudsen diffusion. The talk illustrates how TAP experiments provide unique insights into complex heterogeneous catalytic reactions, how TAP data provides intrinsic kinetics, and can be directly compared with steady-state data.

The data presented includes experiments using a single micron-sized particle, an ultra-sparse metal deposit on an inert support, and an experiment revealing the evolution of adsorbed surface structures. The unique examples show how a series of transient curves reveal details of the interactions of individual reactants with a catalyst surface as a function of temperature. State-defining and state-altering experiments are described along with how the evolution of TAP data can be used to infer structure forming processes on a catalytic surface.