Unveiling the key factor for the phase reconstruction and exsolved metallic particle distribution in perovskites.

ABSTRACT: To significantly increase the amount of exsolved particles, the complete phase reconstruction from simple perovskite to Ruddlesden-Popper (R-P) perovskite is greatly desirable. However, a comprehensive understanding of key parameters affecting the phase reconstruction to R-P perovskite is still unexplored. Herein, we propose the Gibbs free energy for oxygen vacancy formation in Pr_0.5(Ba/Sr)_0.5TO_3-δ (T = Mn, Fe, Co, and Ni) as the important factor in determining the type of phase reconstruction. Furthermore, using in-situ temperature & environment-controlled X-ray diffraction measurements, we report the phase diagram and optimum 'x' range required for the complete phase reconstruction to R-P perovskite in Pr_0.5Ba_0.5-xSr_xFeO_3-δ system. Among the Pr_0.5Ba_0.5-xSr_xFeO_3-δ, (Pr_0.5Ba_0.2Sr_0.3)₂FeO_4+δ - Fe metal demonstrates the smallest size of exsolved Fe metal particles when the phase reconstruction occurs under reducing condition. The exsolved nano-Fe metal particles exhibit high particle density and are well-distributed on the perovskite surface, showing great catalytic activity in fuel cell and syngas production.

SUBMITTER: Kim H 

PROVIDER: S-EPMC8613209 | biostudies-literature | 2021 Nov

REPOSITORIES: biostudies-literature