Invited Talk: Screening and Characterization of Reduction/Oxidation-Active Reactions of Mixed Ionic-Electronic Conducting Materials for Air Separation
- Type: Conference Presentation
- Conference Type: AIChE Annual Meeting
- Presentation Date: November 20, 2020
- Duration: 16 minutes
- Skill Level: Intermediate
- PDHs: 0.30
Redox activity screenings were performed via thermogravimetric analysis (TGA, Netzsch STA 449 F3 Jupiter) for a temperature range of 300 to 1200 Â°C, in 0 and 20% O2Â/Ar. Changes in oxygen non-stoichiometry were quantified from measured mass losses to determine air separation capacity. Larger non-stoichiometry changes were seen in the A-sited doped samples. Of B-site substituents, only Co enhanced SrFeO3-Î´ reducibility. Most samples reduced continuously as temperature increased. The largest reduction extents were observed for Aâ= La and Ba. Samples with Aâ= Ca generally showed faster reduction kinetics under pure Ar; however, there was indication of a potentially reversible phase change around 850 Â°C.
Powder X-ray diffraction was performed on samples after synthesis and after TGA to verify phase stability. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) were performed on La0.1Sr0.9ÂFeO3-Î´ and Ba0.1Sr0.9ÂFeO3-Î´ to investigate particle morphology and elemental distribution before and after thermal reduction and oxidation cycling experiments. SEM showed some smoothing and rounding of particle surfaces after cycling, without significant changes in bulk characteristics and particle sizes. SEM revealed no particle sintering, while EDS showed no evidence of phase segregation in the samples, suggesting promising chemical stability after several thermal cycles.
 H. J. M. Bouwmeester, A. J. Burggraaf, Dense ceramic membranes for oxygen separation, in Membr. Sci.Technol., ed. A. J. Burggraaf and L. Cot., Elsevier, 1996, vol.4, pp. 435â528.
 C. C. Chang and H. S. Weng, Ind. Eng. Chem. Res., 1993, 32(11), 2930â2933.
 H.E. Bush, KP. Schlichting, R.J. Gill, S.M. Jeter, P.G. Loutzenhiser, Design and Characterization of a Novel Upward Flow Reactor for the Study of High-Temperature Thermal Reduction for Solar-Driven Processes, J. Sol. Energy Eng, 2017.
 R. Gill, H.E. Bush, P. Haueter, P.G. Loutzenhiser, "Characterization of a 6 kW high-flux solar simulator with an array of xenon arc lamps capable of concentrations of nearly 5000 suns." 2015, 86 (12), 8.
 J. Vieten, B. Bulfin, M. Roed, C. Sattler, Citric acid auto-combustion synthesis of Ti-containing perovskites via aqueous precursors. Solid State Ionics, 2018. 315: p. 92-97.
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