Characterization of Water Structure on Silver Electrode Surfaces by SERS with Two-Dimensional Correlation Spectroscopy

Abstract

Surface-enhanced Raman scattering (SERS) spectra were collected continuously during cyclic voltammetric measurements on silver electrodes in alkaline aqueous solution at room temperature. Three water librational modes as well as the bending mode peak were observed in cathodic potential range. The 2D-COS analysis of spectra collected in LiOH and KOH solutions showed that the librational bands appear prior to the bending band on the cathodic scan, while in CsOH solution the potential dependence of these bands was identical. A comparison of librational band frequencies revealed that the water molecules around Cs(+) cations arranged on the electrode surface were poorly hydrogen bonded in contrast to Li(+) and K(+). The water bending band of spectra collected in LiOH solution was found to be the convolution of two contributions, consistent with a two state model of water arranged on an electrode surface.

Surface enhanced Raman scattering substrates based on titanium nitride nanorods

“…Hence it has attracted much attention from analysis, chemistry, and biology fields [1][2][3][4][5][6]. Generally, materials used as SERS substrates are mainly metallic (in particular Ag, Au, Cu noble metals) nanoparticles (NPs) or some types of nanostructure (such as metal nanoshells [7], metal nanowires [8], and metal nanodots [9,10], nanoporous films [11]).…”

Surface‐enhanced Raman scattering of molecules adsorbed on Co‐doped ZnO nanoparticles

“…Recently, surface‐enhanced Raman scattering (SERS) has been widely used as a powerful tool for structural analysis and supersensitive detection in a variety of fields from biomaterials to the solid state 1–4. Owing to its convenient operation and spectroscopic multiplexing, SERS is considered to be a promising universal method for single‐molecule detection.…”

In Situ Surface-enhanced Raman Analysis of Water Libration on Silver Electrode in Various Alkali Hydroxide Aqueous Solutions

“…Recently, Ambrosio et al have investigated the characterization of water structure on Ag electrode by SERS. 23 This report has revealed that the two-dimentional correlation spectra for water libration modes on Ag electrodes. The two-dimentimal correlation spectra have suggested that water structure around alkaline ions depends on alkaline metal.…”

“…5(b), which shows the results when using D 2 O instead of H 2 O, the intensity in the Raman band between 380 and 650 cm ¹1 increased gradually with decreasing potential. The Raman frequency in these two Raman bands was altered by the isotope effect due to the difference in mass between H and D. 23 Considering the absence of detectable impurities in ion-exchange chromatography, flame atomic absorption spectrometry and inductively coupled plasma analysis, these Raman bands are almost identical to those for the libration of H 2 O and D 2 O molecules on the electrode surface. Next, we discuss the increase in Raman intensity with decreasing potential and the decrease in Raman intensity with decreasing ionic radius of the alkali metal ion, which indicates species dependence.…”