Post annealing investigations of thin praseodymia films on Si(111)

Due to its large oxygen capacity and oxygen mobility praseodymia is interesting for applications in modern heterogenous catalysis. For instance the selectivity of praseodymia for carbon compounds is advantageous in olefiant gas synthesis. The investigation of annealing processes leads to a better understanding of the oxygen transport in the praseodymia films. In this context thin PrO2 films were annealed at temperatures from 300 C up to 600 C under UHV conditions before they were analysed with spot analysis profile low electron energy diffraction (SPALEED). The diffraction pattern indicates a phase transition to Pr2O3 at the surface. Furthermore X-ray diffraction experiments (XRD) show a partial subsurface phase transition from PrO2 into various oxidation states including Pr2O3