An thin film of the di-decatungstosilicate with a tetra-ruthenium(IV)-oxo core and its electrochemical properties

A ruthenium-containing polyoxometalate Rb8K2[{Ru4O4(OH)2(H2O)4}(γ-SiW10O36)2]·25H2O (RuSiW10) with two redox-active centers of Ru and W was assembled on quartz, and ITO by the layer-by-layer self-assembly method. The regular assembled process was monitored by collecting UV–vis spectra of film after each bilayer recycle. The electrochemical properties were studied by cyclic voltammetry and hydrodynamic amperometry. The composite film showed electrocatalytic activity towards reduction of NO2- attributing to SiW10 units, and oxidation of ascorbic acid, benzyl alcohol, and dimethyl sulfoxide (DMSO) arised from the Ru4O6 core. It may provide a novel material as bifunctional electrocatalyst for oxidation and reduction reactions, and amperometric sensor for the detection of NO2- and ascorbic acid.