A facile synthesis of Pt nanoflowers composed of an ordered array of nanoparticles

Platinum nanoflowers (Pt NFs) composed of an ordered assembly of nanoparticles were synthesized by an ethanol reduction of [PtCl6](2-) under a reflux condition (85 degrees C) at pH 2.5 in the presence of PVP (molecular weight 10,000) as a structure-directing agent. Optical and transmission electron microscopic (TEM) studies confirmed the reduction of [PtCl6](2-) into Pt-0 followed by its growth to form Pt NPs of a size of similar to 4 nm, which were then assembled into ordered NFs through epitaxial growth along the (111) plane. The mechanism of the Pt NFs' formation with respect to the use of PVP of different molecular weights and the pH of the reaction is discussed in detail