TY - JOUR
T1 - Raman spectroscopy of active-carbon electrodes when Au colloids are placed at the electrolyte/electrode interface
AU - Grebel, H.
AU - Zhang, Yuanwei
N1 - Publisher Copyright: © 2024 Elsevier B.V.
PY - 2024/3/1
Y1 - 2024/3/1
N2 - 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.
AB - 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.
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U2 - 10.1016/j.chemphys.2023.112171
DO - 10.1016/j.chemphys.2023.112171
M3 - Article
SN - 0301-0104
VL - 579
JO - Chemical Physics
JF - Chemical Physics
M1 - 112171
ER -