Noble metal nanoparticles have been widely studied due to their use in catalysis, photonics, electronics, sensing, and biomedicine. While it is known that their properties and performance can be tuned through prudent control of morphology, the differences and similarities in formation route for particles of disparate geometry and crystallinity are not well understood. Here we report a comprehensive study of the process by which colloidal noble metal nanoparticles having several distinct shapes nucleate and grow when employing the polyol synthesis. Through analysis of aliquots taken during the reactions, we found that, for all morphologies, metal clusters with diameters &lt;2 nm first nucleated as a stable intermediate following precursor reduction and prior to the initiation of widespread growth. These nucleated clusters served as embryonic seeds that grew to form monodisperse metal nanoparticles of varying shapes. Extensive high-resolution transmission electron microscopy revealed that the growth pathway – monomer addition, coalescence, or a combination of the two – was different for each of three different morphologies, and was likely directed by the interactions of each specific anionic ligand with the metal surfaces. Although we focus primarily on synthesis of Rh nanoparticles, studies on Pt and Pd suggest this formation route is general for the synthesis of noble metal nanoparticles by the polyol process.

Ligand-induced fate of embryonic seeds in the shape-controlled synthesis of rhodium nanoparticles

249th National Meeting (2015)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.