American Chemical Society
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Keggin Ions as UV-Switchable Reducing Agents in the Synthesis of Au Core−Ag Shell Nanoparticles

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journal contribution
posted on 2003-06-21, 00:00 authored by Saikat Mandal, PR. Selvakannan, Renu Pasricha, Murali Sastry
Keggin ion-mediated synthesis of Au core−Ag shell bimetallic nanoparticles is described. Exposure of photochemically reduced aqueous (PW12O40)3- Keggin ions to AuCl4- ions leads to the formation of stable gold nanoparticles capped by the Keggin ions. The surface-bound Keggin ions may then be activated by UV irradiation and, upon exposure to Ag+ ions, reduce the metal ions to form a silver shell around the gold core. That the capping agent not only stabilizes the metal nanoparticles but also plays the role of a switchable reducing agent is a highlight of this approach with important implications in nanomaterials synthesis and catalysis.