Transient Electrochemical Tip Surface-Enhanced Raman Spectroscopy (EC-Tip-SERS): Concept and Applications in Electrocatalysis and Material Science
Abstract
The development of electrochemical techniques combined to Raman spectroscopy such as electrochemical Tip-
or Surface- Enhanced Raman spectroscopy (EC-TERS or EC-SERS) have attracted considerable attention over
the past years by the scientific community. This spectro-electrochemical combination provides an accurate view
over electrochemical processes occurring at an electrode by acquiring simultaneously local topography, and
vibrational fingerprints about the material or molecules under potential control.[1] Based on the use of an
insulated TERS tip, we introduced recently a new approach that we called EC-Tip-SERS (Figure 1). Here,
electroactive molecules are adsorbed directly onto the tip that acts both as working microelectrode and single
hotspot for SERS.[3] Although the spatial resolution is lost in this configuration, interesting transient mechanistic
information can be obtained. In this communication, we will present first the use of this technique on a redox-
and Raman- active model molecule, the Nile blue, in which a temporal resolution in the order of millisecond can
be easily attained. Then, we will consider the use of Tip-SERS in probing molecular motion within rotaxane-
based giant assemblies containing porphyrins derivatives. Finally, we will demonstrate the use of transient EC-
Tip-SERS in scrutinizing electrocatalytic transient mechanisms, such as those associated to the oxygen
reduction reaction towards hydrogen peroxide in water using viologen SAMs as electrocatalyts.
References
[1] Ding, S. Y., Yi, J., Li, J. F., Ren, B., Wu, D. Y., Panneerselvam, R., & Tian, Z. Q. Nature Reviews Materials, 1,
(2016) 1-16.
[2] Touzalin, T., Joiret, S., Maisonhaute, E., & Lucas, I. T. Analytical chemistry, 89 (2017) 8974-8980.