Zirconium-peroxo embedded in non-stoichiometric yttria stabilized zirconia (110) from first-principles

Metal-peroxo species on oxides are recognized as important intermediates for catalytic reactions on oxides. In this work, surface structures of stoichiometric and non-stoichiometric yttria stabilized zirconia (YSZ) were investigated for the low index surfaces (111), (110), and (100) by using first principles electronic structure calculations, and the energetic stabilities of non-stoichiometric surfaces with respect to the stoichiometric ones were calculated as a function of oxygen chemical potential. In the oxygen-rich condition, a unique form of zirconium-peroxo embedded in the lattice oxygen sites was found in YSZ(110); the embedded peroxo was recently confirmed in experimental observations for TiO₂ anatase (101) (M. Setvín et al., Science 341 (2013) 988) and cubic In₂O₃ (001) (D. R. Hagleitner et al., Phys. Rev. B 85 (2012) 115441). The electronic structure of the embedded peroxo found in O-rich YSZ(110) was analyzed in details by means of orbital energy diagrams and density of states.