Cubic phase stabilization, structural, optical and oxygen permeation characteristics of Ce/Zr doped (Ba0.50Sr0.50)(Fe1-p-qCepZrq)O3-δ (p = 0, 0.10; q = 0–0.90) ceramic membranes

The perovskite-type ceramic oxides have gained relevant attention due to their technological applications in electrochemical devices, catalysts, oxygen-separable membranes, and fuel cells. An attempt has been made here to synthesize (Ba 0.50 Sr 0.50 )(Fe 1-p-q Ce p Zr q )O 3-δ (p = 0, 0.10; q = 0–0.90) oxides via an oxalate-based sol-gel route. It exhibits cubic (Pm3m) → {cubic (Pm3m) + orthorhombic ( Pnma )} → cubic (Pm3m) structural phase transformation with zirconium (q) and finally stabilizes in the cubic phase. The lattice parameter increases as a c = ∼4.0985–4.2014 Å for p = 0.10, q = 0.60–0.90. X-ray photoelectron studies reveal the presence of various ions with their possible valence states viz., iron (Fe) and cerium (Ce) both are in 3+ and 4+ oxidation states. The adsorbed oxygen vacancies (O − ) increase as the structure transforms to single cubic phase. The oxygen permeability (Jo 2 ) of each membrane composition increases with temperature and lies in the range of ∼1.539–1.572 ml/cm 2 .min for p = 0.10, q = 0.20–0.90 at 950 °C. Cubic lattice parameter (a c ) and activation energy values (E a ) are consistent with observed oxygen permeability data. The obtained results and ‘δ’-values (∼0.014–0.258) suggest the applications of these oxides in various technological devices.