| 초록 |
Redox ex-solution, in-situ synthesis process of metal nanoparticles upon high-temperature reduction has widely been studied as a way to fabricate metal nanocatalyst-decorated oxide for energy conversion devices. However, the underlying mechanisms related to this phenomenon are not completely understood and practical solutions that effectively accelerate B-site cation ex-solutions in perovskite oxide (ABO3) have not yet been proposed. Here, the degree of Co ex-solution at the surface of SrTi0.75Co0.25O3-δ epitaxial thin films is controlled through the engineering of metal-oxygen bond length. Combined theoretical and experimental analyses show that the stretched Co-O bond can promote the Co ex-solution in SrTi0.75Co0.25O3-δ. Based on these findings, Co ex-solution can be remarkably promoted to improve the surface CO oxidation reactivity of SrTi0.75Co0.25O3-δ, when a large-sized isovalent dopant is added. This method to promote ex-solution can be readily applied to various heterogeneous catalysts. |
