SERS investigation of interfacial water at a silver electrode in acetonitrile solutions

On the Occurrence of Competitive Adsorption at the Platinum−Acetonitrile Interface by Using Surface-Enhanced Raman Spectroscopy

“…This may be caused by both the rather low detection sensitivity and the rather small Raman scattering cross section for water molecules. However, because of the great enhancement of the surface Raman signal for silver, the SERS bands of trace water have been observed at the roughened silver electrode−acetonitrile interface in our laboratory 6 SERS spectra from a roughened Pt electrode at different potentials in 0.1 M H 2 O + 0.1 M LiClO 4 /acetonitrile. …”

Characteristic wavenumber shifts of the stimulated Raman scattering from interfacial water molecules induced by laser‐induced plasma generation at air–water and water–silver interfaces

“…19 By SERS measurements, the vibrational spectra in the OH stretching region arose only from a special complex involving silver atoms (cluster), halide ions, cations, and water rather than free water molecules at the water-silver interface and did not include a peak at around 3200 cm 1 . 20 In contrast, Du et al 21 reported that the interfacial water at a negatively charged quartz surface gave a strong characteristic peak at 3200 cm 1 by SFG measurements. They assigned the peak to the interfacial ice-like water formed by the strong electrostatic field due to fully ionized silanol groups at the quartz surface.…”

Electrochemical quartz crystal impedance study on the electrodeposition of LiOH onto a gold electrode in acetonitrile containing LiClO4· 3H2O and its application in preparing a Pt-plated porous polypyrrole thin film for the catalytic electrooxidation of methanol

“…In ACN containing 0.1 mol L À1 LiClO 4 AE 3H 2 O (or NaClO 4 AE 2H 2 O), the average critical concentration in the diffusion layer for the precipitation of LiOH (S dl(LiOH) ) or NaOH (S dl(NaOH) ) is calculated from the oxygen-reduction charge consumed just when an obvious decrease in f 0 was observed (Q p ), and an effective diffusion-layer thickness of (pDt p ) 0.5 , where t p is the time period from the onset of the oxygen-reduction current and to the onset of the obvious decrease in f 0 , and the diffusion coefficient of the dissolved oxygen in ACN (D) is roughly assumed to be 1 · 10 À5 cm 2 s À1 for the rough estimations of S dl(LiOH) and S dl(NaOH) . generation of OH À at so positive potentials, but the generation of OH À via the reduction of dissolved oxygen or possible oxygen impurities even after deaeration treatments was overlooked [14].…”

“…Interestingly, Gu et al recently reported via surface-enhanced Raman spectroscopy (SERS) characterization that ACN solvent molecules could be partially dissociated to cyanide anions at certain negative potentials at roughened SERS-active Au, Pt and Cu electrodes, as a result of the photopromoted electrochemical reduction of CH 3 CN at the electrode location illuminated by the laser [13]. More recently, Cao et al reported via SERS studies of interfacial water at a silver electrode in ACN containing 0.1 M anhydrous LiClO 4 that in addition to the decomposition of ACN observed at negative potentials, the trace amount of interfacial water can interact with the silver electrode via both O-and H-end surface adsorption, and the existence of closely associated Li + OH À ion pair and the resulting quasi-crystalline species is proven via the observation of the narrow intense bands at 3665 and 328 cm À1 [14]. However, the quantification of the interfacial LiOH (or NaOH) precipitate generated during an electrochemical modulation in ACN containing LiClO 4 AE 3H 2 O (or NaClO 4 AE 2H 2 O) has, to our knowledge, not been examined until this work.…”