DFT study of the stability of oxygen vacancy in cubic ABO3 perovskites
DFT study of the stability of oxygen vacancy in cubic ABO3 perovskites
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DOI：
10.1007/s10853-014-8731-0
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发表时间：
2015-02
影响因子：
4.5
通讯作者：
Hai-Yan Su;Keju Sun
中科院分区：
文献类型：
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作者：
Hai-Yan Su;Keju Sun
具有通式ABO3的稀土和碱土金属钙钛矿作为最先进的燃料电池的电催化剂以及制氢和碳氢化合物氧化的催化剂而备受关注。通过掺杂 A 和 B 来调节离子电导率以及随后形成的氧空位对于钙钛矿材料的性能至关重要。为了深入了解影响氧空位稳定性的因素并了解掺杂钙钛矿材料活性的起源，我们使用密度泛函理论计算研究了立方 ABO3 钙钛矿（A= La 和/或 Be、Mg、Ca、Sr、Ba；B= Ti、V、Cr、Mn、Fe、Co 和 Ni）的结构和能量学。发现ABO3的晶格常数普遍随着A、B离子半径的增大而增大； ABO3的体形成能被分解为电离能和晶格能，这取决于离子半径和化合价。块体形成能的趋势对应于给定离子价态下的电离能的趋势，而对应于较低价态碱土金属掺杂La时的晶格能的趋势。本体形成能与氧空位形成能之间存在良好的线性关系。这项工作在原子水平上提供了对钙钛矿活性起源的理解。
Rare earth and alkaline earth metal perovskites with general formulaABO3have attracted much attention as electrocatalysts for state-of-the-art fuel cells, and catalysts for hydrogen generation and hydrocarbons oxidation. Tuning the ion conductivity through dopingAandBand subsequent formation of oxygen vacancies is essential for the performance of perovskites materials. To provide insights into factors that affect stability of oxygen vacancies and understand the origin of the activity of doped perovskite materials, we investigate the structure and energetics of cubicABO3perovskites (A= La and/or Be, Mg, Ca, Sr, Ba;B= Ti, V, Cr, Mn, Fe, Co, and Ni) using density functional theory calculations. It is found that the lattice constant ofABO3generally increases as the ionic radius ofAandB; the bulk formation energy ofABO3is decomposed into the ionization energy and lattice energy, which depend on the ionic radius and valence. The trend of bulk formation energy corresponds to that of ionization energy at a given ionic valence, while corresponds to that of lattice energy as doping La by alkali earth metals with lower valence. There exists a good linear relationship between the bulk formation energy and oxygen vacancy formation energy. This work provides an understanding toward the origin of the activity of perovskites at the atomic level.