Stabilization of cubic perovskite structure upon trivalent cation substitution in Co-based mixed conductors (Ba_xSr_(1-x))(Co_(0.9)Y_(0.1))O_(3-δ)

摘要

The stabilization of perovskite through trivalent cation substitution is a promising strategy for the development of oxygen permeation membranes. In this study, perovskite stabilization through yttriumsubstitution in (Ba_xSr_(1-x)) (Co_(0.9)Y_(0.1))O_(3-δ) was investigated and compared with that of Al. A perovskite single phase of (Ba_xSr_(1-x))(Co_(0.9)Y_(0.1))O_(3-δ) was attained at a Ba concentration of 1.0 ≥ x ≥ 0.5, which was higher than the range at which the hexagonal polymorph occurred. This differed from (Ba_xSr_(1-x))(Co0.9Al0.1)O_(3-δ) in which the perovskite occurred at a lower Ba concentration than the hexagonal polymorph. In addition, (Ba_(0.9)Sr_(0.1))(Co_(0.9)Y_(0.1))O_(3-δ) showed good oxygen permeability on a level similar to that of (Ba_(0.5)Sr_(0.5))(Co_(0.8)Fe_(0.2))O_(3-δ).