Electrochemical Behavior and Electrocatalytic Properties of Ultrathin Films Containing Silicotungstic Heteropolyanion SiW[sub 12]O[sub 40]4−]

We describe here a controlled fabrication of ultrathin monolayer and multilayer films consisting of silicotungstic heteropolyanion and a cationic polymer of quaternized poly(4‐vinylpyridine) partially complexed with osmium bis(2,2'‐bipyridine) on Au electrodes previously self‐assembled with cysteamine monolayers based on layer‐by‐layer electrostatic interaction. The thus‐forming monolayer and multilayer chemically modified electrodes are investigated by cyclic voltammetry on their electrochemical behavior and electrocatalytic properties. The composite ultrathin films exhibit remarkable electrocatalytic effects on the reduction of , , and . The electrocatalytic effects on , reduction are enhanced with increasing layer number from 1 to 3 but level off with much thicker multilayers. The stability of the monolayer and multilayer films is also examined. © 2000 The Electrochemical Society. All rights reserved.