Chemical Environment Effects on the Atomic Oxygen Absorption into Pt(111) Subsurfaces

Density functional theory is used to study chemical environment effects such as surface coverage of oxygenated species and presence of adsorbed oxygen reduction intermediate OH and water on the atomic oxygen absorption process into Pt(111) subsurfaces. The results show that increasing the on-surface oxygen coverage can energetically and kinetically stabilize subsurface atomic oxygen present at 0.11 and 0.25 monolayer subsurface coverage. At constant subsurface coverage, the absorption energy barrier increases with increasing on-surface coverage. Adsorbed on-surface OH has similar effects on the atomic oxygen absorption process as those caused by on-surface adsorbed atomic oxygen. A monolayer of water over the on-surface oxygen does not significantly alter the thermodynamics and kinetics of the oxygen absorption process.