High-Performance Evolved Gas Analysis System for Catalyst Characterization

A new, high-resolution system for analyzing and characterizing materials is described. Based on evolved gas analysis (EGA), it can perform both controlled transformation rate thermal analysis and stepwise isothermal analysis as well as conventional (linear temperature program) EGA. Features include a fast-respons furnace, direct temperature measurement, sensitive specific detector, and sophisticated temperature control. The system permits, for the first time, a comparison of the three modes of operation under an identical sample environment. The advantages and limitations of each are illustrated using a sample chosen to model a type of reaction often found in the preparation of catalysts by calcination, the thermal decomposition of hydroxides. It is shown that these methods used with our system have potential advantages in analysis and in the study of complex thermal decomposition processes, by increasing the resolution of consecutive events and providing a more closely controlled sample environment.