Plasmonic Field Effect on the Hexacyanoferrate (III)-Thiosulfate Electron Transfer Catalytic Reaction on Gold Nanoparticles: Electromagnetic or Thermal?

TitlePlasmonic Field Effect on the Hexacyanoferrate (III)-Thiosulfate Electron Transfer Catalytic Reaction on Gold Nanoparticles: Electromagnetic or Thermal?
Publication TypeJournal Article
Year of Publication2009
AuthorsYen, CW, EL-Sayed, MA
JournalJournal of Physical Chemistry C
Volume113
Pagination19585-19590
Date PublishedNov
ISBN Number1932-7447
Accession NumberWOS:000271428300035
Abstract

The rate of the catalytic reaction between hexacyanoferrate (III) and thiosulfate on gold nanoparticles is found to increase when irradiated with light in resonance with surface plasmon absorption of the gold nanoparticles. Turning on the plasmonic field by turning on light at the surface plasmon extinction band wavelength could increase the rate by one of two possible mechanisms. In the first one, the electromagnetic field could chan-e its radiative or nonradiative electron transfer process (Mechanism I). In the other mechanism (Mechanism II), the strongly absorbed light by the gold nanoparticles is rapidly converted from light energy into heat energy that increases the temperature of the medium and increases the reaction rate. In order to determine which mechanism the plasmonic catalytic effect follows, we determined the activation energy of the reaction by heating the reaction solution via two different methods: irradiation at the surface plasmon resonance of the gold catalyst and by direct heating in a thermostat. The two activation energies are found to be the same, suggesting that the plasmonic field effect in this electron transfer reaction is thermally induced.

DOI10.1021/jp905186g