Absorption of Atomic Oxygen into Subsurfaces of Pt(100) and Pt(111):  Density Functional Theory Study

Density functional theory is used to examine binding energies and the most stable sites of atomic oxygen adsorbed on Pt(111) and Pt(100) surfaces as a function of surface coverage, as well as to evaluate the absorption energies and the energetically most favorable sites of atomic oxygen located in the subsurface, as a function of subsurface coverage. Based on the absorption energies, it is found that the tetrahedral site underneath the hcp hollow site is energetically the most favorable site to absorb atomic oxygen in the subsurface of Pt(111), and the tetrahedral site underneath the bridge site is the corresponding energetically most favorable subsurface site in Pt(100) cells. Minimum energy paths identified for the diffusion of low-coverage adsorbed atomic oxygen into the subsurface sites for Pt(111) and Pt(100) cells indicate the existence of high kinetic barriers to such diffusion.