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

Abstract

Water libration on a silver electrode in various alkali hydroxides (MOH, M = Li, Na, K or Cs) aqueous solutions was examined through simultaneous experiments using surface-enhanced Raman scattering (SERS) and electrochemical analysis. This technique, referred to as SERS spectroelectrochemistry, reveals the Raman spectral band between 200 and 750 cm⁻¹, assignable to water libration on the electrode surface, through electrode potential scanning. The Raman intensity in this spectral band changes with the electrode potential. The variation in Raman intensity of water libration observed when scanning the electrode potential is discussed in terms of water molecules at the electrode interface in various alkali hydroxide aqueous solutions.