Investigations on supported bimetallic PdPt nanostructures

Abstract PdPt bimetallic clusters have been produced by a laser vaporisation source and studied after deposition on a support. We have been able to obtain clusters with a well-defined composition, identical to that of the target rod as deduced from energy dispersive X-ray analysis measurements. An evaporation of Pd atoms upon the impact of the electron beam has been observed, suggesting that the surfaces of the clusters are Pd-enriched. The segregation behaviour using Monte Carlo simulations has been studied for the Pd 15 Pt 85 and Pd 50 Pt 50 cubo-octahedral clusters composed of 586 and 2406 atoms. The results indicate a large Pd segregation in all the systems, in qualitative agreement with the experimental observations, with preferential occupation of corner and edge sites.