A FLOW REACTOR SYSTEM FOR CATALYTIC REACTION STUDIES, ALLOWING TIME-RESOLVED AND SPACE-RESOLVED MEASUREMENTS OF GAS-COMPOSITION AND TEMPERATURE AROUND THE CATALYST

A flow reactor system for catalytic reaction studies is described. The system is equipped with a movable gas sampling device and on-line mas s spectrometry (MS), allowing time- and space-resolved measurements of gas composition and temperature. Results from H-2 oxidation on Pt are used to illustrate the system performance. Spatial variations of H-2, O-2, and H2O concentrations can be measured, e.g., during mass transp ort limited conditions. Temporal variations in H-2, O-2, and H2O durin g chemical oscillations are well resolved close to the catalyst, but s uccessively smeared away at increasing distance. The special design of the gas sampling probe allows quantible MS measurement even of H2O an d other ''difficult'' gases, and of gas temperature variations.