Density functional theory on the comparison of the Pd segregation behavior at LaO- and FeO2-terminated surfaces of LaFe1−xPdxO3−y

First-principles calculations were carried out to study the difference in the segregation behavior of Pd on the LaO and FeO2 terminated surfaces of LaFe1−xPdxO3−y perovskite oxide. Without oxygen vacancy, the tendency of Pd to segregate near to the LaO- and FeO2-terminated surfaces is rather weak. Oxygen vacancies enhance the surface segregation of Pd significantly at FeO2 terminated surfaces, while they do not at LaO terminated surfaces. Combined with the previous thermodynamic calculations, we propose that Pd-containing perovskite catalyst should be prepared at high temperature to enhance the surface segregation of Pd and to form suitable surface geometries for rapid switching between oxidized and reduced states of Pd catalyst on perovskite support. The origin for the large difference in the segregation tendency of Pd between LaO and FeO2 terminated surfaces is also discussed.