Oxygen Storage Property and Chemical Stability of SrFe1–xTixO3−δ with Robust Perovskite Structure

5 years ago

Oxygen Storage Property and Chemical Stability of SrFe1–xTixO3−δ with Robust Perovskite Structure

Saburo Hosokawa, Akito Demizu, Tsunehiro Tanaka, Kentaro Teramura, Kazuo Kato, Hiroyuki Asakura, Kosuke Beppu

The compounds of SrFe_1–xTi_xO_3−δ with a robust perovskite structure are synthesized by Ti substitution for Fe sites in SrFeO_3−δ, and they display improved oxygen storage properties and chemical stability in a CO₂ atmosphere. The oxygen storage rate of SrFe_0.8Ti_0.2O_3−δ is over 5 times faster than that of SrFeO_3−δ. Further, in the presence of CO₂, SrFe_1–xTi_xO_3−δ with x ≥ 0.2 maintains its oxygen storage property, whereas, for x ≤ 0.1, the oxygen release rate drastically deteriorates due to the formation of SrCO₃. The perovskite structures (space group I4/mmm) of SrFe_1–xTixO_3−δ (x ≥ 0.2) are preserved even after reduction treatment under a H₂ atmosphere at 773 K. In contrast, the material with x ≤ 0.1 undergoes a phase transformation from perovskite (I4/mmm) to brownmillerite structures (Ima2), and the latter easily reacts with CO₂ to form a large amount of SrCO₃ on the surface. Thus, the robust perovskite structure maintains its original framework despite the reduction treatment, resulting in improved oxygen storage rate as well as the CO₂ resistance.

Publisher URL: http://dx.doi.org/10.1021/acs.jpcc.7b06078

DOI: 10.1021/acs.jpcc.7b06078