TPD-MS study of carbonation and hydration of Yb2O3(C)

Abstract

A TPD-MS study of the behaviour of Yb2O3(C) against atmospheric environment has been carried out. Contrary to suggestions in the literature, the results show that after prolonged atmospheric exposure (3 years) bulk hydration and carbonation of ytterbia take place. If this sample, previously regenerated by calcination in helium flow at 870 K, is exposed to the atmosphere up to 80 hours, only surface reactions seem to occur. The present study, in which several CO2 and H2O treatments have been included, suggests that over Yb2O3, the hydration and carbonation reactions are related to each other, the amount and thermal stability of adsorbed CO2 being determined by the surface water content. The discussion of the results is based on a surface model of Yb2O3.