Surface segregation in ternary Pt–Pd–Rh alloys studied with Monte Carlo simulations and the modified embedded atom method

Recently, new parameters for the modified embedded atom method (MEAM) were derived for the ternary Pt–Pd–Rh system. In this work, this validated potential is used in conjunction with Monte Carlo (MC) simulations to study segregation to the (1 1 1) surface for the entire phase diagram of this ternary system. At 1400 K, these simulations reveal two distinct regions. In the major part of the phase diagram, Pd is the segregating component. However, close to the binary Pt–Rh axis, a region is observed in which Pt and Pd co-segregate to the surface. This co-segregation occurs only at higher temperatures as it is the result of two competing exothermic segregation reactions.