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TitleIn situ and ex situ studies of platinum nanocrystals: Growth and evolution in solution
Publication TypeJournal Article
Year of Publication2009
AuthorsCheong, S., Watt J., Ingham B., Toney M.F., and Tilley R.D.
JournalJournal of the American Chemical Society
Pagination14590 - 14595
Date Published2009
ISSN00027863 (ISSN)
Keywordsarticle, Branched structures, concentration (parameters), controlled study, Etching process, Ex situ, Faceted morphology, Growth mechanisms, growth rate, Growth stages, High resolution transmission electron microscopy, In-situ, In-Situ Study, molecular evolution, morphology, Morphology transformations, nanocrystal, Nanocrystals, nanomaterial, Platinum, Platinum nanocrystals, Precursor concentration, Reaction rates, Selective growth, solution and solubility, synchrotron, TEM, Thermodynamics, Transmission electron microscopy, X ray diffraction, X ray diffraction analysis, XRD
AbstractIn 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. © 2009 American Chemical Society.

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