Characterization of Redox States of Nickel Hydroxide Film Electrodes by In-situ Raman Spectroscopy

摘要

Thin films of nickel hydroxide deposited on gold electrodes have been characterized in detail by in-situ surface Raman spectroscopy in conjunction with electrochemical techniques. Raman spectra were obtained for film thicknesses varying from less than one equivalent monolayer to several hundred monolayers, as determined from the faradaic charge for the cyclic voltammetric oxidation of Ni(OH)2. For the thinnest films, Raman bands at 455/cm and at 480 and 560/cm were obtained for the reduced and oxidized films, respectively, using 647.1 nm excitation at roughened gold. These signals, identified with Ni-OH and Ni-O vibrations from deuterium isotope data, were diagnosed as arising from surface-enhanced Raman scattering (SERS) in view of their absence for the reduced film when using the latter conditions for thicker oxidized films, which were consistent with resonance Raman scattering (RRS).