Reaction of Platinum Nanocatalyst with the Ferricyanide Reactant to Produce Prussian Blue Analogue Complexes

TitleReaction of Platinum Nanocatalyst with the Ferricyanide Reactant to Produce Prussian Blue Analogue Complexes
Publication TypeJournal Article
Year of Publication2007
AuthorsMahmoud, MA, EL-Sayed, MA
JournalThe Journal of Physical Chemistry C
Volume111
Issue46
Pagination17180 - 17183
Date Published2007
ISBN Number1932-7447
Abstract

The field of catalysis with colloidal nanoparticles is in its infancy. The question of whether the catalysis occurs on the surface of the nanoparticle (thus heterogeneous) or homogeneously in solution using a complex made by the nanoparticle is now being debated. Thus, the molecular mechanism of nanocatalysis has not yet been studied in detail. The first step in this effort is to study the molecular mechanism of the reaction of each reactant with the nanoparticle. This letter is an effort in this direction. A great deal of research has used platinum nanoparticles (PtNPs) to catalyze electron-transfer reactions such as that between thiosulfate and hexacyanoferrate III. We monitored this reaction in detail using optical, Raman, and IR spectroscopies. By increasing the reaction time, two sequential dominant species are formed. The first one is found to have spectral signatures of a Prussian blue analogue with a structure of K[PtIIFeIII(CN)6]. With increasing time, the intensity of the spectrum of this complex is found to decrease, whereas a spectrum similar to that of a complex having the structure of [PtIVFeII(CN)6] increased. A mechanism for the formation of these metal-mixed valency Prussian blue analogues is given.The field of catalysis with colloidal nanoparticles is in its infancy. The question of whether the catalysis occurs on the surface of the nanoparticle (thus heterogeneous) or homogeneously in solution using a complex made by the nanoparticle is now being debated. Thus, the molecular mechanism of nanocatalysis has not yet been studied in detail. The first step in this effort is to study the molecular mechanism of the reaction of each reactant with the nanoparticle. This letter is an effort in this direction. A great deal of research has used platinum nanoparticles (PtNPs) to catalyze electron-transfer reactions such as that between thiosulfate and hexacyanoferrate III. We monitored this reaction in detail using optical, Raman, and IR spectroscopies. By increasing the reaction time, two sequential dominant species are formed. The first one is found to have spectral signatures of a Prussian blue analogue with a structure of K[PtIIFeIII(CN)6]. With increasing time, the intensity of the spectrum of this complex is found to decrease, whereas a spectrum similar to that of a complex having the structure of [PtIVFeII(CN)6] increased. A mechanism for the formation of these metal-mixed valency Prussian blue analogues is given.

URLhttp://dx.doi.org/10.1021/jp709735n
DOI10.1021/jp709735n
Short TitleJ. Phys. Chem. C