|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Energy Materials 2017: Materials for Energy Conversion with Emphasis on SOFC
||Oxygen Reduction Reaction Mechanisms on Ruddlesden-Popper Cathodes for Intermediate-Temperature Solid Oxide Fuel Cells
||Wenyuan Li, Bo Guan, Xinxin Zhang, Xingbo Liu
|On-Site Speaker (Planned)
Ruddlesden-Popper (R-P) phases have been investigated widely as IT-SOFC cathodes. ORR mechanism for R-P phase is investigated using (LaSr)2NiO4±δ as example. The governing factors of ORR are identified as oxygen adsorption and incorporation based on the findings in reaction orders, stoichiometry-related chemical capacitances and intrinsic anisotropic properties. The incorporation rate depends on the amount of interstitial oxygen. Since the unfilled interstitial sites in R-P phase serve to accommodate the adsorbed oxygen during incorporation, like vacancies in the perovskite, more oxygen interstitial would seem to suppress the kinetics of this process. In regard to this, a physical model is proposed to reconcile the discrepancy between the experimental results and intuitive reasoning. This model explains how oxygen interstitial works to regulate the exchange rate, and the contradiction between oxygen vacancy and oxygen interstitial is harmonized so that the latter in the R-P structure also positively promotes the incorporation rate in ORR.
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