Electrochemical nanoimpacts monitoring, developed within the last decade, is based on the time-resolved detection of stochastic collisions of individual NanoParticles (NPs) in micro/nano-confined electrochemical cells. Although electrochemical techniques are now able to measure electron transfer processes associated to single NP impacts, they are not spatially resolved and fail to characterize complex multiple chemical events.
Superlocalization optical microscopies have recently allowed a complementary visualization of the transformation of NPs during electrochemical reactions. We proposed the coupling of holographic microscopy to electrochemistry to record scattering by individual NPs. Real-time holograms are reconstructed in order to superlocalize and track several individual NPs in 3D with 3x3x10 nm3 accuracy. During Ag electrodissolution experiments, it allowed the 3D monitoring of Brownian or phoretic motion and individual dissolution. In situations where chemical transformations occur, spectroscopy associated to finite element or FDTD modelling can provide additional information on individual NPs during electrochemical processes.
We will illustrate the possibilities of this coupled characterization in several systems, where 3D particle tracking can provide a NP size estimate during the Brownian approach of the particle. During chemical reactions on the metal interface, we will show that holography, spectroscopy, associated to an optical model of the scattering, gives access to relevant information on the size, position, and composition of the NPs.
Y.Zhou et al, Angew. Chem. 2011,
X.Xiao et al. J. Am. Chem. Soc. 2007
 V.Brasiliense et al., Acc. Chem. Res., 2016
V.Brasiliense et al. J. Am. Chem. Soc., 2016
A.N Patel et al. Nano Lett., 2015