Si原子在CeO2(111)表面吸附与迁移的第一性原理研究

为探究Si原子在CeO₂(111)表面吸附的微观行为，采用第一性原理的方法研究了Si原子在CeO₂(111)表面的吸附作用、电子结构和迁移过程，计算了Si原子在CeO₂(111)表面的吸附能，最稳定及次稳定吸附位置的电子态密度与电荷密度分布、迁移激活能。计算结果表明：Si原子最易吸附于基底表层的O原子上，其中O桥位（O_bri）吸附作用最强，O顶位（O_t）和O三度位（O_h）吸附强度次之。Si原子仅对其最邻近的表层O原子结构影响较大，这与Si原子及其最邻近的O原子间电荷密度重叠程度增强的结果一致。Si原子最易围绕着O_t位从O_bri位向O_h位迁移，迁移所需激活能为0.849 eV。

First Principle Calculation on Adsorption and Diffusion Behavior of Si Atom on CeO2(111) Surface

In order to research the microscopic behavior of Si atom adsorbed on CeO₂(111) surface, the adsorption, electronic structure and diffusion behavior of Si atom on CeO₂(111) surface were studied using the first principle method. The adsorption energy was calculated. The electron states density, charge density distribution, diffusion activation energy of the most and sub-stable adsorption sites of Si atom on the CeO₂(111) surface were also calculated. The results show that Si atom is most easily adsorbed on the surface layer of O atoms, in which the O bridge site (O_bri) has the strongest adsorption, and the adsorption strength at the O top site (O_t) and the O three-fold site (O_h) is second. Si atom only has a great influence on the structure of the nearest surface of O atoms, which is consistent with the increase of the charge density overlap between the Si atom and its nearest neighbor O atoms. The Si atom most easily diffuses from the O_bri site to O_h site while around the O_t site, and the required activation energy for diffusion is 0.849 eV.