| 초록 |
The stability and activity of solid oxide fuel cell (SOFC) can be enhanced with the exsolution of catalytic nanoparticles. When exsolution occurred via phase transition of perovskite (ABO3) to Ruddlesden-Popper phase (R-P, A2BO4), it is enhanced by the discarded B-metal during phase transition. To find the condition for phase transition to R-P, we proposed that selectively spontaneous reduction in BO2 layer is an essential condition for the phase transition to R-P. In our density functional theory (DFT) study, we found that the reduction in BO2 layer was promoted by Sr dopant, and selective reduction in BO2 layer without surface decomposition was only possible for Pr0.5Sr0.5MnO3 (PSMO) and Pr0.5Sr0.5FeO3 (PSFO) among Pr0.5(Ba/Sr)0.5MO3 perovskites (M: transition metal). In in-situ XRD measurement, we showed that the complete phase transition of PSFO, and verified that the exsolution and the phase transition of Pr0.5Ba0.5FeO3 (PBFO) to R-P can be promoted by Sr doping, as predicted in our DFT study. These results may guide further development of a highly stable and active fuel electrode for high performance SOFC. |
