Investigation of Oxygen Adsorption Behavior on Platinum Surface Based on a First-Principles Calculation

In this study, adsorption behavior of oxygen on platinum surface in Pt/C-based catalysts used for oxygen reduction was investigated in terms of the surface plane and lattice distortion of platinum by a first-principles calculation. The calculations revealed that Pt(110) surface has higher oxygen adsorption stability than Pt(111) surface. Dissociative adsorption of the oxygen molecule was observed only in the model with a distortion of about -4% on the Pt(111) surface, whereas such reaction was observed on many Pt(110) surface even with and without distortions. In other words, both surface distortion and surface plane would play important roles for the oxygen adsorption behavior of ORR, suggesting that the Pt/C-based catalysts prepared with a large amount of Pt(110) surface with distortions exposed are more likely to proceed through a pathway involving dissociative adsorption of molecular oxygen.