Measurements and evaluation of the hydrogen uptake in Yb-doped strontium cerate

Abstract

The water uptake of SrCe0.95Yb0.05O3-α was studied by in situ thermogravimetry. At different temperatures, mass changes due to variations of water vapour pressure were recorded; from these, the remaining vacancy concentrations were calculated. Further analysis in terms of the equilibrium constant was carried out without any assumptions on the initial vacancy concentration. The requirement of an ideal solution behaviour led us to the introduction of an effective vacancy concentration differing from the nominal one. At last, a universal mastercurve is presented showing the fraction of vacancies occupied as a function of a normalized pressure.