A kinetic Monte Carlo study of Pt on Au(111) with applications to bimetallic catalysis.

Pt-decorated Au nanostructures and bimetallic PtAu nanoparticles have been shown to act as catalysts. Consequently we investigate the formation of extended Pt decorations of an Au island edge on Au(111) as possible catalysts. The investigation is by simulation using the kinetic Monte Carlo method. The effects of varying the rate of deposition of Pt atoms and the simulation temperature on the morphology of the resulting Pt nanostructures were investigated. The thickness and roughness of the nanostructures are readily influenced, with temperature being the more important factor. A combination of both high temperature and low deposition rate was the most effective at reducing the roughness. PtAu alloying in the Au island edge was identified. This work is (to the best of our knowledge) the first kinetic Monte Carlo simulation study of the formation of Pt nanostructures on Au. We demonstrate how the morphology of the Pt nanostructures can be controlled. The nanostructures studied here, comprising an adjustable mix of Pt overlayers and novel 1D PtAu surface alloys, are expected to be of considerable interest as potential bimetallic nano-catalysts.