First-principles investigation on the segregation of Pd at LaFe1-x Pd x O3-y surfaces
1 Division of Precision Science & Technology and Applied Physics, Graduate School of Engineering, Osaka University, 2-1, Yamada-okaSuita, Osaka 565-0871, Japan
2 Insitute of Scientific and Industrial Research, Osaka University, 8-1 MihogaokaIbaraki, Osaka 567-0047, Japan
3 Advanced Institute for Materials Research (AIMR), Tohoku University, Sendai 980-8577, Japan
4 Department of Physics and Earth Science, Faculty of Science, University of the Ryukyus, 1 SenbaruNishihara, Okinawa 903-0213, Japan
5 Elements Strategy Initiative for Catalysts and Batteries (ESICB), Kyoto University, Katsura, Kyoto 615-8520, Japan
Nanoscale Research Letters 2013, 8:203 doi:10.1186/1556-276X-8-203Published: 1 May 2013
First-principles calculations were performed to investigate the effect of Pd concentration and oxygen vacancies on the stability of Pd at LaFeO3 surfaces. We found a much stronger tendency of Pd to segregate by taking the aggregation of Pd at LaFe1-xPdxO3-y surfaces into consideration, resulting in a pair of Pd-Pd around a vacancy. Moreover, we predicted that one oxygen-vacancy-containing FeO2-terminated surfaces would be stable at high temperatures by comparing the stability of LaFe1-xPdxO3-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.