Optimizing Oxygen Reduction Catalyst Morphologies from First Principles
Optimizing Oxygen Reduction Catalyst Morphologies from First Principles
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DOI：
10.1021/acs.jpcc.5b05460
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发表时间：
2015-07-23
影响因子：
3.7
通讯作者：
Harrison, Nicholas M.
中科院分区：
文献类型：
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作者：
Ahmad, Ehsan A.;Tileli, Vasiliki;Harrison, Nicholas M.
钙钛矿对氧还原(ORR)的催化活性与过渡金属的体积d电子占有率相关。我们对合成模型进行了扩展，成功地再现了LaMnO_3相对分子的高活性。对于其他钙钛矿，通过处理催化剂表面形貌作为优化OAR的一个重要方面。从第一性原理出发，确定了正交型(Pnma)LaMnO_3低指数面上反应中心的性质。O-2的吸附明显受局部几何构型和强电子关联的影响。在实验证实的对称破坏Jahn-Teller扭曲的六个反应位置中，只有一个位置与O-2结合了一个中间结合能，同时促进了超氧化物的形成，超氧化物是碱性介质中重要的ORR中间体。对于LaMnO_3，合理设计催化剂形态以促进特定的活性中心是先进的功能性ORR催化剂的一种高效的优化策略。
Catalytic activity of perovskites for oxygen reduction (ORR) was recently correlated with bulk d-electron occupancy of the transition metal. We expand on the resultant model, which successfully reproduces the high activity of LaMnO3 relative. to other perovskites, by addressing catalyst surface Morphology as an important aspect of the optimal OAR. catalyst The nature of reaction sites on low index surfaces of orthorhombic (Pnma) LaMnO3 is established from First Principles. The adsorption of O-2 is Markedly influenced by local geometry and strong electron correlation. Only one of the six reactions sites that result from experimentally confirmed symmetry-breaking Jahn-Teller distortions is found to bind O-2 with an intermediate binding-energy while facilitating the formation of superoxide; an important ORR intermediate in alkaline media. As demonstrated here for LaMnO3, rational design of the catalyst morphology to promote specific active sites is a highly effective Optimization strategy for advanced functional ORR catalysts.