Synthesis and Characterization of Pt Dendrimer-Encapsulated Nanoparticles: Effect of the Template on Nanoparticle Formation

Autor:	Valeri Petkov, Heechang Ye, Michael G. Weir, V. Sue Myers, Richard M. Crooks, William D. Pyrz, Marc R. Knecht, Douglas J. Buttrey, Anatoly I. Frenkel
Rok vydání:	2008
Předmět:	Absorption spectroscopy Chemistry General Chemical Engineering Nanoparticle General Chemistry Catalysis Autocatalysis Crystallography X-ray photoelectron spectroscopy Chemical engineering Dendrimer X-ray crystallography Materials Chemistry Spectroscopy
Zdroj:	Chemistry of Materials. 20:5218-5228
ISSN:	1520-5002 0897-4756
DOI:	10.1021/cm8004198
Popis:	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 PtCl4 2- /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 Pt 2+ /dendrimer precursor complex is either fully reduced, to yield a DEN having a size and structure consistent with the original PtCl4 2- /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 Pt 2+ ions. Details concerning the formation of the Pt 2+ /dendrimer precursor are also discussed.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::fed98eaa76583cb7b0c54738d129d95f https://doi.org/10.1021/cm8004198 Zobrazit plný text záznamu