Electrochemical behavior and multilayer films of the sandwich-type polyoxotungstate complex {K10Co4(H2O)2(PW9O34)2}

The electrochemical behavior of the sandwich-type polyoxotungstate complex of K10Co4(H2O)2(PW9O34)2 (Co4(PW9)2) was investigated by cyclic voltammetry in aqueous solutions. The polyoxoanion exhibits two successive redox peaks originating from the tungsten-oxo framework. The electrochemical behavior for the CoII species was not detected. Moreover, the multilayer films consisting of PEI and Co4(PW9)2 were prepared by the layer-by-layer self-assembly method. The films were characterized by UV–vis spectroscopy, cyclic voltammetry and atomic force image. The films exhibit the electrochemical behavior of Co4(PW9)2 polyoxoanion. Moreover, the films can catalyze the electrochemical reduction of NO2−. Electron transfer to Fe(CN)63−/4− redox probe was also investigated.