Co and Fe co-doping influence on functional properties of SrTiO3 for use as oxygen transport membranes

Abstract

Perovskite-structured powders of SrTi1-xCoxO3-δ (STC-x) with nominal stoichiometry of x=0-0.75 as well as SrTi0.75Co0.25-yFeyO3-δ (STCF-y) where y=0-0.25 were synthesized using the Pechini method. Thermal/chemical expansion behaviour, total electrical conductivities, and oxygen permeation rates were investigated. The substitution of Ti with Co leads to an increase in both electronic and ionic conductivities and, therefore, oxygen permeability. Thermal and chemical expansions also increase slightly. The optimum Co content was found to be 25-35% due to the trade-off between phase stability and permeability. The oxygen permeation rate of STC35 is comparable to that of state-of-the-art (La,Sr)(Co,Fe)O3-δ, whereas the expansion coefficients are lower. Co-doping in STCF-y did not produce any significant differences in oxygen permeability at both high temperature and sample thickness (1.0 mm), i.e. in a solid-state diffusion-limited regime. At lower temperatures (<800 °C), STC25 exhibits higher permeability than STF25 due to the higher catalytic activity of Co compared to Fe.

Ceramic Membranes: Materials – Components – Potential Applications

“…Ferrites and cobaltites in particular offer high permeability (in combination with low stability). Strontium‐titanate‐based materials are a promising alternative , with much higher stability. In composites, doped ZrO 2 or CeO 2 are most commonly used as ion conductors.…”

Fe and Co-doped (Ba, Ca)TiO3 Perovskite as Potential Electrocatalysts for Glutamate Sensing

“…For the Co doped SrTiO3, the single phase still existed as Co doping content increased to 50 mol%. According to S. Qiu et al and A. Murashkina et al homogenous solid solution can be obtained in Fe doped BaTiO3 system at the doping concentration ranging from 20 to 50 mol% [16][17][18].…”

“…In addition to flavor enhancement, glutamate is also reported to function as an excitatory neurotransmitter. Concentrations of glutamate in human brains are in the range between 1 and 300 μM [16]. Nevertheless, excessive glutamate concentration in brains can be detrimental.…”

Keramische Membranen: Materialien – Bauteile – potenzielle Anwendungen

“…Insbesondere Ferrite und Cobaltite bieten hohe Permeabilität (bei geringer Stabilität). Strontiumtitanat‐basierte Werkstoffe bieten eine vielversprechende Alternative , mit deutlich verbesserter Stabilität. Für Komposite kommen im Wesentlichen dotiertes ZrO 2 oder CeO 2 als Ionenleiter in Frage.…”