Raman spectroscopy of active-carbon electrodes when Au colloids are placed at the electrolyte/electrode interface

Document Type

Article

Publication Date

3-1-2024

Abstract

Surface enhanced Raman spectroscopy (SERS) was used to study active-carbon (A-C) electrodes in super-capacitors cells; these electrodes were functionalized with Au nanoparticles (AuNPs). We observed a large enhancement in the cell's specific capacitance as a function of the AuNPs concentration. Cell capacitance is a volumetric effect while SERS is susceptible to the local number of colloids. The intensity ratio between the D-line (defect line) and the graphitic line (G-line), ID/IG, of the A-C electrode proved to be a good marker, independent of the measurement point. Rather than a peak, typical of amorphous films, this ratio has a dip at a particular AuNPs concentration, which is shifted upon the presence of the electrolyte. It is suggested that the seemingly unrelated phenomena - the capacitance enhancement and the intensity dip - are the result of the formation of a quasi-2D array of AuNPs at the interface between the electrolyte and the electrode.

Identifier

85183420159 (Scopus)

Publication Title

Chemical Physics

External Full Text Location

https://doi.org/10.1016/j.chemphys.2023.112171

ISSN

03010104

Volume

579

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