Structure Prediction of Metal Nanoparticles Using Wulff Theorem and First Principles Calculation

Abstract

Metal nanoparticles are useful as catalysts having specific reactivity owing to highly reactive site and strong size dependency. Structural information of metal nanoparticles is essential for interpretation and prediction of their reactivity. Wulff theorem predicts the equilibrium structures of crystals by using the surface energies of plane indices such as (111), (110), and (100). In this study, we evaluated the surface energies of well-defined Rh surfaces by the first principles calculations, followed by systematically constructing various sizes of Rh nanoparticles based on the Wulff theorem. For small nanoparticles with radii of 2 nm or less, only the (111) and (100) planes were present. On the other hand, high index surfaces appeared at large nanoparticles, of which the radii were more than 2.5 nm.