Tunable Oxygen Vacancy Formation Energetics in the Complex Perovskite Oxide SrxLa1鈥?i>xMnyAl1鈥?i>yO3

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• 作者：Ann M. Deml ; Vladan Stevanovi膰 ; Aaron M. Holder ; Michael Sanders ; Ryan O鈥橦ayre ; Charles B. Musgrave
• 刊名：Chemistry of Materials
• 出版年：2014
• 出版时间：November 25, 2014
• 年：2014
• 卷：26
• 期：22
• 页码：6595-6602
• 全文大小：352K
• ISSN：1520-5002

文摘

The composition dependence of oxygen vacancy formation energies (E_V) in the complex perovskite Sr_xLa_1鈥?i>xMn_yAl_1鈥?i>yO₃, a material system demonstrated to significantly outperform ceria for solar thermochemical (STC) fuel production, was investigated using a combination of ab initio and experimental techniques. Density functional theory calculations predict that E_V as a function of composition spans a large range from near 0 to over 3 eV under standard conditions and exhibits trends consistent with equilibrium oxygen nonstoichiometries we determined using thermogravimetric analysis. Our findings show that the strong sensitivity of E_V to composition arises from the composition dependence of the Fermi energy relative to the O 2p band center. From these results, we identify the range of E_V particularly suited for STC cycles for a given set of reduction and oxidation reaction conditions and present a materials design strategy for the optimization of E_V through compositional tuning.