Synthesis and characterization of Pt dendrimer-encapsulated nanoparticles: Effect of the template on nanoparticle formation

Marc R. Knecht, Michael G. Weir, V. Sue Myers, William D. Pyrz, Heechang Ye, Valeri Petkov, Douglas J. Buttrey, Anatoly I. Frenkel, Richard M. Crooks

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Abstract

In this article, we provide a detailed description of the synthesis and properties of Pt dendrimerencapsulated nanoparticles (DENs) prepared using sixth-generation, hydroxyl-terminated, poly(amidoamine) (PAMAM) dendrimers (G6-OH) and three different PtCl42-/G6-OH ratios: 55, 147, and 240. Results obtained from UV-vis spectroscopy, X-ray photoelectron spectroscopy, electron microscopy, X-ray absorption spectroscopy, and high-energy X-ray diffraction show that only a fraction of the Pt 2+/dendrimer precursors are reduced by BH4- and that the reduction process is highly heterogeneous. That is, after reduction each Pt2+/dendrimer precursor complex is either fully reduced, to yield a DEN having a size and structure consistent with the original PtCl 42-/dendrimer ratio used for the synthesis, or the precursor is not reduced at all. This result is consistent with an autocatalytic process that entails slow formation of a nascent catalytic Pt seed within the dendrimer, followed by rapid, catalytic reduction of nearby Pt2+ ions. Details concerning the formation of the Pt2+/dendrimer precursor are also discussed.

Original languageEnglish (US)
Pages (from-to)5218-5228
Number of pages11
JournalChemistry of Materials
Volume20
Issue number16
DOIs
StatePublished - Aug 26 2008
Externally publishedYes

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ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry

Cite this

Knecht, M. R., Weir, M. G., Myers, V. S., Pyrz, W. D., Ye, H., Petkov, V., Buttrey, D. J., Frenkel, A. I., & Crooks, R. M. (2008). Synthesis and characterization of Pt dendrimer-encapsulated nanoparticles: Effect of the template on nanoparticle formation. Chemistry of Materials, 20(16), 5218-5228. https://doi.org/10.1021/cm8004198