(617fo) First-Principles Study for Controlling the Cation Segregation on the Surface of Perovskite Oxide Catalysts
In this study, a key driving force of A-site cation segregation was elucidated for the two classes of perovskite-type materials using density functional theory (DFT) calculations; alkaline earth metal (Ba, Sr, and Ca)-doped LaBO3 (B = Cr0.50Mn0.50, Mn, Fe, Co0.25Fe0.75, Co, and Ni) and SrTi1-xFexO3. In both cases, elastic energy of A-site cation is a dominant factor governing the segregation phenomena, which depends on the size of constituent ions in the perovskite oxide. Based on these results, we suggest simple ways how to suppress the cation segregation by reducing the elastic energy. We believe that our results will be useful to rationally design the SOFC cathodes.