Monte Carlo Simulation of the Size and Composition of Bimetallic Nanoparticles Synthesized in Water in Oil Microemulsions

Abstract

Structural features of bimetallic nanoparticles synthesized in w/o microemulsion have been examined by using a coarse model solved by Monte Carlo simulations. The microemulsion was modeled as spherical droplets containing either two metal salts or reducing agent, and the processes occurring during the collision of the droplets and leading to nucleation and growth of the bimetallic nanoparticles were determined by a set of variables. The bimetallic nanoparticle structure is mainly determined by the difference in the reduction rates of the two metal ions and the excess of reducing agent. An intermetallic structure is always obtained when both reduction reactions take place at about the same rate. When the metal ions have very different reduction potentials, a core−shell to intermetallic structure transition is found at increasing the excess of the reducing agent. An enhancement of the intermetallic structure at the expense of the core−shell, one can be obtained either by decreasing the concentration of both...