Nanocomposite multilayer films containing Dawson-type polyoxometalate and cationic phthalocyanine: Fabrication, characterization and bifunctional electrocatalytic properties

Water-soluble cationic phthalocyanine — Alcian blue (AB) and 2:18 tungstophosphate anions (P2W18) were alternately deposited on a -aminopropyltriethoxysilane-modified indium tin oxide-coated glass electrodes or quartz substrate through a layer-by-layer method. The resulting organic-inorganic hybrid films were characterized by ultraviolet-visible absorption spectra, cyclic voltammetry and X-ray photoelectron spectra. A stepwise and regular deposition of AB and P2W18 in both pure water and 0.01 M poly(styrenesulfonate) (PSS) were investigated. Differences in linear growth were observed between pure water and 0.01 M PSS-based solutions. The voltammetric curves show well-defined anodic and cathodic peaks, which is indicative of both electrocatalytic oxidation and reduction of nitrite.