Ligand effects on the size and purity of Pd nanoparticles

Palladium nanoparticles (Pd-NPs) were prepared by a single-phase reduction of palladium acetate in the presence of different organic thiol ligands. Sizes, size distributions and crystallinity of the Pd-NPs were determined by high resolution transmission electron microscopy (HR-TEM) and powder X-ray diffraction (XRD) while thermogravimetric analysis coupled with mass spectroscopy (TGA-MS) was employed to measure their organic ligand to palladium ratios and to quantify contaminants. No systematic effect of the different ligands on the size and purity of the Pd-NPs was observed but 1st-generation Frechet dendron thiols had an about 4 times larger foot-print at the surface of the NPs than the other thiol ligands.