Several methods are commonly employed to test the thermal stability of catalysts:
Thermogravimetric Analysis (TGA) TGA measures the change in mass of a catalyst sample as it is heated. This technique helps identify decomposition temperatures and other thermal events that might affect the catalyst's stability.
Temperature-Programmed Desorption (TPD) TPD studies involve heating the catalyst in the presence of an adsorbed species and monitoring the desorption of that species. This helps understand the strength and stability of adsorbed species on the catalyst surface.
X-Ray Diffraction (XRD) XRD is used to determine the crystalline structure of the catalyst before and after thermal treatment. Changes in the diffraction pattern can indicate phase transitions or sintering.
Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) These microscopy techniques provide detailed images of the catalyst's morphology and structure. They help identify physical changes such as sintering or particle growth due to thermal stress.
Temperature-Programmed Reduction (TPR) and Temperature-Programmed Oxidation (TPO) TPR and TPO are used to study the redox properties of catalysts. These methods involve heating the catalyst in a reducing or oxidizing atmosphere and monitoring the changes. They help understand how thermal conditions affect the reduction and oxidation states of active sites.
