氧原子在Pt(111)表面和次表层的吸附与扩散

Adsorption and diffusion of oxygen on Pt(111) surface and subsurface

氧原子在Pt表面的吸附和扩散是理解氧化和腐蚀等问题的基础.基于密度泛函理论和周期平板模型研究了氧原子在Pt(111)表面及次表层的吸附,通过扫描隧道显微镜(STM)的理论计算分析了吸附的结构特征.采用CI-NEB方法讨论了氧原子在Pt(111)表面和次表层的扩散过程.研究结果表明氧原子在Pt(111)表面的扩散比较容易,而氧原子向次表层的扩散相对较难,这主要是因为次表层的扩散需要经过一个Pt原子层,必须克服一定的能垒,从而说明过渡金属Pt具有很强的抗氧化性.

The adsorption and the diffusion of oxygen on the Pt（111） surface and subsurface are basic issues to understand oxidation and corrosion,which are investigated based on the density functional theory and the periodic slab model.The absorption structure is analyzed through scanning tunneling microscopy（STM） image.The diffusion processes of oxygen atoms on Pt（111） surface and subsurface are discussed in detail using the CI-NEB method.The results show that the diffusion of oxygen atoms over Pt（111） surface is easier than the diffusion into the subsurface,which is mainly because the diffusion of the subsurface needs to go through a layer of Pt atoms and must overcome a certain energy barrier.Transition metal Pt is indicated to have a strong antioxidant activity.