Theoretical investigations on the potential-induced formation of Pt-oxide surfaces
Theoretical investigations on the potential-induced formation of Pt-oxide surfaces
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DOI：
10.1016/j.jelechem.2007.03.023
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发表时间：
2007-09-01
影响因子：
4.5
通讯作者：
Jacob, Timo
中科院分区：
文献类型：
--
作者：
Jacob, Timo
采用扩展的从头算原子热力学方法结合密度泛函理论计算，研究了铂电极在高电位电化学环境中的界面结构和组成。在氧化物形成的电极电位区，计算了α-PtO，β-PtO，和PtO块体氧化物的块体体系和所有低指数表面。根据体氧化物的形成能，我们首先推导出体氧化物为介电稳定相的稳定范围。与实验观察一致，我们发现在实验温度和压力条件下，α-PtO 2和β-PtO 2块体氧化物在1.2 V以上是稳定的，而PtO需要Δ phi > 1.3 V。（p，T，phi）-相图显示出α-PtO 2 O（001），β-PtO 2（110）和PtO（100）的优先性，甚至在其表面上也具有块状组合物。然而，在薄氧化物层的情况下，也可能存在NO成分。(c)2007 Elsevier B. V.保留所有权利。
Using the extended ab initio atomistic thermodynamics approach together with density functional theory calculations the interfacial structure and composition of Pt-electrodes in electrochemical environments at elevated electrode potentials was studied. Focusing on the electrode potential region, at which the oxide-formation occurs, the bulk systems and all low-index surfaces of alpha-PtO,, beta-PtO,, and PtO bulk-oxides were calculated. On the basis of the bulk-oxide formation energies we first deduced the stability ranges at which the bulk-oxides are the thermodynamically stable phases. In agreement with experimental observations, we find that at experimental temperature and pressure conditions alpha-PtO2 and beta-PtO2 bulk-oxides are stable above 1.2 V, while PtO requires Delta phi > 1.3 V. Afterwards the corresponding (p, T, phi)-phase diagrams of surface structures were obtained, showing a preference for alpha-PtO2O(001), beta-PtO2(110), and PtO(100), respectively, having bulk-like compositions even on their surfaces. However, in case of thin oxide layers a NO composition might also be present. (c) 2007 Elsevier B.V. All rights reserved.