On the atomic structure of Pt(1 1 1)/γ-Al2O3(1 1 1) interfaces and the changes in their interfacial energy with temperature and oxygen pressure

Abstract 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 γ-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 γ-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, Al2) the oxygen-terminated γ-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.