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Correlated Electrochemical and Optical Detection Reveals the Chemical Reactivity of Individual Silver Nanoparticles
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posted on 2016-02-22, 00:00 authored by Vitor Brasiliense, Anisha
N. Patel, Ariadna Martinez-Marrades, Jian Shi, Yong Chen, Catherine Combellas, Gilles Tessier, Frédéric KanoufiElectrochemical
(EC) impacts of single nanoparticles (NPs) on an
ultramicroelectrode are coupled with optics to identify chemical processes
at the level of individual NPs. While the EC signals characterize
the charge transfer process, the optical monitoring gives a complementary
picture of the transport and chemical transformation of the NPs. This
is illustrated in the case of electrodissolution of Ag NPs.
In the simplest case, the optically monitored dissolution of individual
NPs is synchronized with individual EC spikes. Optics then validates in situ the concept of EC nanoimpacts for sizing and counting
of NPs. Chemical complexity is introduced by using a precipitating
agent, SCN–, which tunes the overall electrodissolution
kinetics. Particularly, the charge transfer and dissolution steps
occur sequentially as the synchronicity between the EC and optical
signals is lost. This demonstrates the level of complexity that can
be revealed from such electrochemistry/optics coupling.