Catalytic oxidation activity of Pt3O4 surfaces and thin films

The catalytic oxidation activity of platinum particles in automobile catalysts is thought to originate from the presence of highly reactive superficial oxide phases which form under oxygen-rich reaction conditions. Here we study the thermodynamic stability of platinum oxide surfaces and thin films and their reactivities towardoxidation of carbon compounds by means of first-principles atomistic thermodynamics calculations and molecular dynamics simulations based on density functional theory. On the Pt (111) surface the most stable superficial oxide phase is found to be a thin layer of PtO2, which appears not to be reactive toward either methane dissociation or carbon monoxide oxidation.