title: In situ and ex situ studies of platinum nanocrystals: growth and evolution in solution.
abstract: In situ studies on the growth and evolution of platinum nanocrystals in solution were carried out using synchrotron-based X-ray diffraction (XRD) techniques. Ex situ low- and high-resolution transmission electron microscopy (TEM) were used to investigate the nanocrystal morphologies through the different growth stages. In a reaction with low precursor concentration, both XRD and TEM results show that growth occurs at a relatively slow rate and yields faceted morphologies, which are characteristic of a thermodynamically controlled regime. In contrast, the platinum nanocrystals in the high-concentration reaction form branched structures and grow at much greater rates under a kinetically controlled regime. Additionally the growth mechanism of the high-concentration reaction involves a morphology transformation from octapod-like shapes to porous nanostructures, which is brought about by a novel mechanism involving selective growth and etching processes that occur simultaneously and at comparable rates.
authors.affiliation: School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington 6012, New Zealand.
authors.forename: Soshan
authors.initials: S
authors.lastname: Cheong
authors.forename: John
authors.initials: J
authors.lastname: Watt
authors.forename: Bridget
authors.initials: B
authors.lastname: Ingham
authors.forename: Michael F
authors.initials: MF
authors.lastname: Toney
authors.forename: Richard D
authors.initials: RD
authors.lastname: Tilley