Layer-by-Layer Assembly of Silicotungstate Multilayer Films Modified on Glassy Carbon Electrode and Their Electrochemical Behaviors

A new electrode was modified by multilayer films composed of heteropolyanion (SiW₁₂) and cationic polymer poly(diallyldimethylammonium chloride) through electrochemical growth. The modified electrode electrochemical behavior, the effect of solution pH and electrocatalytic response to the reduction of BrO₃^- and NO₂^- have been investigated. The result shows that the electrochemical process of multilayer films modified electrode including SiW₁₂ is a reversible process by electrochemical step. One-electron process has no proton participation in the first step, and one-electron process is accompanied by one proton participation in the second step and two-electron process is accompanied by two protons participation in the third step. The films grow uniformly, and the peak currents increase with increasing layer numbers. The peak currents increase with scan rate, and the reduced potentials of multilayer films shift negatively with increasing pH. The electrochemical mechanism of multilayer films was suggested.