On The Atomic Structure Of Pt(111)/Gamma-Al2o3(111) Interfaces And The Changes In Their Interfacial Energy With Temperature And Oxygen Pressure

Metal/metal-oxide interfaces are important in many applications including metal coatings, sensing, and catalysis. Here we investigate and predict the structure and chemical bonding of the interface between gamma-Al2O3 and Pt using density functional theory. Previous high-resolution transmission electron microscopy studies showed atomically flat interfaces between the (1 1 1) planes of Pt and gamma-Al2O3; this interfacial orientation is studied herein. A simulated temperature-pressure equilibrium configuration diagram shows how the stability of the interfaces changes with temperature and oxygen pressure. Of the three interfacial terminations (O, Al, Al-2) the oxygen-terminated gamma-Al2O3 (1 1 1) is the most stable at atmospheric conditions. The stability of this interface is attributed to the strong electrostatic interaction between the Pt and the oxygen atoms at the oxygen-terminated interface. This work provides essential insights into the atomic structure and the origins of the interactions at the interface between transition metals and metal-oxides, as well as interfacial configuration at a range of conditions.