Adsorption and surface diffusion of Pt atoms on hydroxylated MgO(001) surfaces

摘要

Density-functional theory calculations have been used to investigate adsorption and surface dynamics of Pt atoms on MgO(001) surfaces with surface-functional hydroxyl groups. Our calculation results show that the adsorption of Pt on hydroxylated MgO(001) is considerably enhanced by interactions among Pt, OH, and MgO surface atoms. We also find that the formation of PtOH complexes instead of Pt dimers is clearly favorable. This behavior is very similar to that of Au deposition on hydroxylated MgO(001). With regard to the surface kinetics, however, the behavior is quite different. Indeed, after the formation of PtOH on MgO(001), the surface diffusion of PtOH is found to be enhanced, as compared to that of Pt on MgO(001). This behavior is in sharp contrast with the low surface mobility previously observed for AuOH on MgO(001). Finally, the reason for this difference is discussed, based on the calculated electronic structures and charge states of Pt on hydroxylated MgO(001).