abstract
Electrochemical impedance spectroscopy (EIS) has been used to study multilayer films containing anionic iron-substituted silicotungstate [SiW(11)Fe(III)(H(2)O)O(39)](5-) (SiW(11)Fe) and positively charged poly(ethylenimine) self-assembled by the layer-by-layer method on glassy carbon and indium tin oxide electrodes. The effect of the charge of the outermost layer of the multilayer assembly on the electron transfer of soluble species was studied using the redox probes [Fe(CN)(6)](3-) and [Ru(NH(3))(6)](3+); cyclic voltammetry indicating that the surface charge has a significant effect on the process. EIS demonstrated that the electrostatic attraction or repulsion between the surface and the redox probes plays a significant role. Analysis of the impedance spectra showed that the charge transfer resistance increases with an increasing number of bilayers for both redox probes and that the porosity of the multilayer film, which varies with the electrode substrate, also has a significant effect on the electrochemical response. (C) 2011 Elsevier Ltd. All rights reserved.
keywords
UV-VIS SPECTROMETRY; MULTILAYER FILMS; POLYELECTROLYTE FILMS; CYCLIC VOLTAMMETRY; COMPOSITE FILMS; ELECTROCATALYTIC PROPERTIES; HOMOGENEOUS CATALYSIS; HYBRID FILMS; POLYOXOMETALATE; SPECTROSCOPY
subject category
Electrochemistry
authors
Fernandes, DM; Ghica, ME; Cavaleiro, AMV; Brett, CMA
our authors
Ana Maria Vieira Silva Viana Cavaleiro
Full professorGroups