Abstract
Platinum nanocrystals and their derivatives with palladium and cobalt are of fundamental interest due to their wide field of application in chemistry and physics. Their properties are strongly dependent on their shape and composition. However the chemical route is far from allowing control of both shape and composition. In this paper, we show both experimentally and theoretically the important role of the interaction of small adsorbed molecules on the shape but also on the composition. This has been studied by comparing the case of pure palladium and platinum nanocrystals and the case of PtPd and PtCo nanoalloys synthesized by the liquid-liquid phase transfer method.
Highlights
Platinum nanocrystals and their derivatives with palladium and cobalt are of fundamental interest due to their wide field of application in chemistry and physics
The chemical route is far from allowing control of both shape and composition. We show both experimentally and theoretically the important role of the interaction of small adsorbed molecules on the shape and on the composition. This has been studied by comparing the case of pure palladium and platinum nanocrystals and the case of PtPd and PtCo nanoalloys synthesized by the liquid–liquid phase transfer method
The present work aims at shedding light on the complexity of the control of the nanomorphology and composition, as it needs a ne tuning of the various physical–chemical parameters to establish a general framework of growth of metallic or bimetallic nanoparticles in solution
Summary
Paper on the nanometer scale, as the properties are strongly dependent on the size and the surface state (raw or capped), it is crucial to develop methods where the polydispersity in size and composition is nely controlled. Density functional theory (DFT) calculations show the key role of hydrogen in the formation of cubic platinum shapes. These results illustrate, both experimentally and theoretically, the primordial role of the capping agent and of the dissolved gases issued either from air or as a byproduct of the reaction, which may strongly in uence the shape and the composition of NCs. In particular, platinum nanocubes are obtained only in the presence of an H2 overpressure, due to a preferential adsorption on (100) facets compared to the (111) facets, whereas it is not possible to control the shape of palladium nanocrystals under similar conditions due to a difference in the nature of the interaction of H2 with the palladium surfaces. The present work aims at shedding light on the complexity of the control of the nanomorphology and composition, as it needs a ne tuning of the various physical–chemical parameters to establish a general framework of growth of metallic or bimetallic nanoparticles in solution
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