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Exploring perovskites for methane activation from first principles

机译：探索对甲烷活化钙钛矿第一原理

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The diversity of perovskites offers many opportunities for catalysis, but an overall trend has been elusive. Using density functional theory, we studied a large set of perovskites in the ABO(3) formula via descriptors of oxygen reactivity such as vacancy formation energy, hydrogen adsorption energy, and the first C-H activation energy of methane. It was found that changing the identity of B within a period increases the oxygen reactivity from the early to late transition metals, while changing A within a group has a much smaller effect on oxygen reactivity. Within the same group, B in the 3d period has the most reactive lattice oxygen compared to the 4d or 5d period. Some perovskites display large differences in reactivity for different terminations. Further examination of the second C-H bond breaking on these perovskites revealed that larger A cations and non-transition metal B cations have higher activation energies, which is conducive to the formation of coupling products instead of oxidation to Co or CO2. Balance between the first C-H bond breaking and methyl desorption suggests a just right oxygen reactivity as described by the hydrogen adsorption energy. These insights may help in designing better perovskite catalysts for methane activation.
机译：钙钛矿提供了许多的多样性催化的机会,而是一个总体趋势一直难以捉摸。理论,我们研究了大量的钙钛矿ABO血型(3)公式通过描述符的氧气反应如空位形成能、氢吸附能,第一个碳氢键活化能的甲烷。一段时间内改变B的身份增加了从早期氧气反应过渡金属,而内改变组织对氧的影响要小得多反应性。期最被动的晶格氧4或5 d相比。显示大反应的差异不同的终端。第二个碳氢键打破这些钙钛矿显示更大的阳离子和非过渡金属阳离子有更高的激活能量,这有利于形成耦合吗产品而不是氧化有限公司或二氧化碳。第一个碳氢键断裂和之间的平衡甲基氧解吸表明恰到好处氢反应性描述吸附的能量。设计更好的钙钛矿催化剂的甲烷激活。

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