Designing Iron-Based Layered Perovskite Oxides with Optimized Oxygen Storage Performance and Structural Stability

Oxygen storage materials (OSMs) play a significant role in automotive catalysts and oxygen separation systems. Here, we examine the oxygen storage ability of Ruddlesden-Popper-type layered perovskites An+1FenO3n+1−δ (A = Sr, La) using temperature-programmed reduction with H2 (H2-TPR) and thermogravimetry (TG) measurements. As a result, we found that the oxygen storage capacity exhibited an increasing trend with the number of perovskite layers. Furthermore, time-resolved X-ray diffraction measurements revealed reaction dynamics during the redox reactions, visualizing the process of phase changes and reaction times. Among the compounds we examined, LaSr3Fe3O10−δ with triple perovskite layers (n = 3) has high structural stability and favorable oxygen storage characteristics. From this perspective, we propose a perovskite-based OSM design guideline to combine oxygen storage perovskite layers and robust rock-salt layers. These findings provide valuable insights into the design of oxygen storage materials.