Elastic properties of two-dimensional Pt with adsorbed oxygen

Previous studies on elastic properties of two-dimensional (2D) metals have focused on thin slabs with a clean surface. However, metal surfaces are full of binding sites for adsorption, which makes them interesting materials in catalysis and sensing. In this contribution, we study Young's moduli of ultrathin oxygen-adsorbed 2D Pt slabs with a (111) surface by density functional theory methods. We show that upon oxygen adsorption, 2D Pt slabs experience significant lattice expansion due to adsorbate-induced additional surface stress. Young's moduli of the studied 2D slabs typically decrease when surface oxygen coverage increases. Moreover, thinner slabs in general exhibit higher stiffness. We show that the nonlinear elastic properties of both the core and surface regions of the considered 2D structures underlie the overall effective elastic properties.