First-principles investigation on the segregation of Pd at LaFe(1-x)Pd(x)O(3-y) surfaces

First-principles calculations were performed to investigate the effect of Pd concentration and oxygen vacancies on the stability of Pd at LaFeO(3) surfaces. We found a much stronger tendency of Pd to segregate by taking the aggregation of Pd at LaFe(1-x)Pd(x)O(3-y) surfaces into consideration, resulting in a pair of Pd-Pd around a vacancy. Moreover, we predicted that one oxygen-vacancy-containing FeO(2)-terminated surfaces would be stable at high temperatures by comparing the stability of LaFe(1-x)Pd(x)O(3-y) surfaces, which further supports our previous conclusion that a Pd-containing perovskite catalyst should be calcined at 1,073 K or higher temperatures in air to enhance the segregation of Pd in the vicinity of surfaces to rapidly transform the Pd catalyst from oxidized to reduced states on the perovskite support.