(262g) Mixing Behavior in Aupt Bimetallic Nanoparticles

Mixing behavior, which refers to the distribution of metal species in an alloy, is known to play an important role in the performance of bimetallic alloy catalysts. AuxPt1-x bimetallic nanoparticles (BNPs) at equilibrium are investigated using Monte Carlo simulations to study Pt distribution in the surface and bulk phase as a function of the particle size, composition x, shape and temperature. We investigate BNPs of truncated octahedron shape, for 0.1-0.9 fractions of Pt at 400K & 600K, and study species distribution for segregated, core-shell and three-shell onion type structures. From these studies, the relation between surface/bulk compositions are established in terms of distribution coefficient. An expression for the distribution coefficients is obtained. Distribution coefficients for Au and Pt are calculated.