A simple method for computing the formation free energies of metal oxides
A simple method for computing the formation free energies of metal oxides
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DOI：
10.1016/j.commatsci.2021.110692
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发表时间：
2021-10
影响因子：
3.3
通讯作者：
Hantong Chen;Qi-Jun Hong;S. Ushakov;A. Navrotsky;A. Walle
中科院分区：
文献类型：
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作者：
Hantong Chen;Qi-Jun Hong;S. Ushakov;A. Navrotsky;A. Walle
本文旨在通过引入虚拟固体氧自由能的概念，提供一种简单的方法来获得固态金属氧化物的形成自由能。该方案旨在解决标准密度泛函理论 (DFT) 方法对于凝聚相和气相之间的能量差异往往表现出较差精度的事实。这个想法是完全根据固体氧化物相定义氧参考态，以便无需计算分子能量即可获得形成自由能。所提出的参考自由能可以很容易地从计算和实验中获得，从而能够直接整合DFT和实验数据。使用钼系统构建此参考，我们计算了 Mo、Cu、Mg、Al 和 Zn 氧化物的 Ellingham 图，所有这些都与实验值吻合良好。该过程与所使用的特定总能量方法无关，并且适用于任何金属氧化物的形成自由能计算。
This paper purposes a simple procedure for obtaining the formation free energy of metal oxides in their solid states by introducing the concept of virtual solid oxygen free energy. This scheme is meant to address the fact that standard Density functional Theory (DFT) methods tend to exhibit poor accuracy for energy differences between condensed and gas phases. The idea is to define an oxygen reference state entirely in terms of solid oxide phases, so that formation free energies can be obtained without having to compute molecular energies. The proposed reference free energy can be easily obtained from both computations and experiments, thus enabling the direct integration of DFT and experimental data. Using the molybdenum system to construct this reference, we compute the Ellingham diagram for oxides of Mo, Cu, Mg, Al and Zn, which all show good agreement with experimental values. This procedure is independent of specific total energy method used, and is applicable to formation free energy calculations of any metal oxides.