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采用从头算原子热力学方法系统研究了Ni-rich和Pt-rich条件下Pt3Ni(111)在不同偏析、表面化学吸附氧覆盖度下560个可能结构的相对稳定性,构建了氧气气氛下Pt3Ni(111)表面结构演化、直至满覆盖化学吸附氧的热力学相图.结果表明,随着氧的化学势的升高,在热力学上仅出现两类稳定的结构,主要包括没有化学吸附氧的干净Pt-skin表面,以及在很低氧的化学势下就形成的含有化学吸附氧的Ni-skin表面,而有化学吸附氧的PtNi表面合金化的中间结构则处于亚稳态.仔细分析发现,这些结构的形成主要由金属的偏析能、氧与两种金属成键强弱的差别、氧的化学势的高低三个因素共同决定.
The ab initio atomic thermodynamics method was used to systematically study the relative stability of 560 possible structures of Pt3Ni (111) under different segregation and surface chemical oxygen saturation under the conditions of Ni-rich and Pt-rich. The structure of Pt3Ni (111 ) Surface structure until it covers the thermodynamic phase diagram of chemisorbed oxygen.The results show that with the increase of the chemical potential of oxygen, only two kinds of stable structures appear in thermodynamics, including the clean Pt- skin surface, as well as the Ni-skin surface containing chemisorbed oxygen at very low oxygen chemical potentials, whereas PtNi surface-alloyed intermediate structures with chemisorbed oxygen are in a metastable state and careful analysis revealed that these structures The formation of mainly by the metal segregation energy, the difference between oxygen and two metal bond strength, the chemical potential of oxygen three factors together determine.