Cobalt-free niobium-doped barium ferrite as potential materials of dense ceramic membranes for oxygen separation
MetadataShow full item record
Cobalt-free perovskite-type oxides with the nominal composition of BaNbyFe1−yO3−δ (y=0.025–0.20) are synthesized and evaluated as materials used in ceramic membranes for oxygen separation. The effects of Nb-doping on the crystal structure, surface morphology, electrical conductivity, chemical bulk diffusion and surface exchange, and oxygen permeability of the oxides are systematically investigated using XRD, SEM, four-probe DC conductivity, electrical conductivity relaxation technique, and oxygen permeation studies. A small amount of Nb-doping induces a sharp increase in electrical conductivity. A further increase in the Nb-doping amount, however, lowers the electrical conductivity as a result of the blocking effect of Nb5+ on electronic conduction. A small amount of Nb-doping has less impact on the sintering capability. From the oxygen permeation test, it was found that Nb-doping could significantly enhance the oxygen permeability, especially below 750 °C. Among all of the compositions, BaNb0.05Fe0.95O3−δ shows the highest oxygen permeation fluxes, reaching 1.35 and 0.61 mL cm−2 min−1 for a membrane with a thickness of 1.0 mm at 900 and 700 °C, respectively. Furthermore, the membrane is rate-controlled mainly by bulk diffusion, indicating the potential to further improve the oxygen permeation flux via a thinner membrane.
Showing items related by title, author, creator and subject.
Effects of niobium doping site and concetration on the phase structure and oxygen permeability of Nb-substituted SrCoOx oxidesZhang, K.; Ran, R.; Shao, Zongping; Zhu, Z.; Jin, Y.; Liu, Shaomin (2010)Niobium doping effect on phase structure, phase stability and electrical conductivity of SrCoOx oxides and oxygen permeability of the corresponding membranes were systematically investigated. Niobium was successfully ...
Zhang, Z.; Chen, Y.; Tade, Moses; Hao, Y.; Liu, Shaomin; Shao, Zongping (2014)In this study, we propose a new tin-doped perovskite oxide, BaCo0.7Fe0.2Sn0.1O3-δ (BCFSn0.1), as a promising alternative material for a ceramic oxygen-permeating membrane. A high energy ball milling-assisted solid-state ...
Optimization of BaxSr1-xCo0.9Nb0.1O3-8 perovskite as oxygen semi-permeable membranes by compositional tailoringZhao, J.; Zhang, K.; Gao, D.; Shao, Zongping; Liu, Shaomin (2010)Mixed conducting SrCo0.9Nb0.1O3−δ perovskite is a newly developed promising ceramic membrane material for air separation. In this work, SrCo0.9Nb0.1O3−δ was further optimized by the introduction of Ba to partially replace ...