The Preparation And Electrocatalytic Properties Based On Polyoxometalate And Correlative Inorganic/organic Composite Films Electrode

the electrochemistry properties of copper(II)-substitute Keggin-typepolyoxometalate [CoW₁₁O₃₉Cu(H₂O)]^6- was investigated in different pH and media, theelectrochemistry behavior observed for the reduction of the tungsten oxo centers for theheteropolyanions was found to be pH dependent. Its characterization by cyclicvoltammetry revealed the stepwise reduction of Cu2+ centers within this heteropolyanionsbefore deposition of Cu(0) on the electrode surface. The presence of chloride ions in thesupporting electrolyte does not induce the extraction of the copper centers from theheteropolyanions. the electroreduction for nitrite was studied also. it is proposed that atransient complex between the Cu(I) in HPA and NO2-is formed initially and the catalyedreduction depend upon the ability of the singly or multiply reduced heteropolytungstatesto deliver electrons to the NO group bound to the copper center.The fabrication of self-assembled ultrathin film has recently attracted considerableinterest in view of their importance to nanomaterials with tailored structures andproperties . The layer-by-layer (LbL) self-assembly method, initially developed for pairsof oppositely charged polyelectrolytes , is a facile and versatile technique that has latelyemerged as a viable approach to prepare large area ultrethin films. In this workwater-soluble cationic phthalocyanine — Alcian blue(AB) and 2:18 tungstophosphateanions (P2W18) were alternately deposited on a 3-aminopropyltriethoxysilane(APS)-modified ITO or quartz substrate through a layer-by-layer (LBL) method in thiswork. The resulting organic-inorganic hybrid films were characterized by UV/Visabsorption spectroscopy and cyclic voltammetry(CV). A stepwise and regular depositionof Alcian Blue and P2W18 in both pure water and 0.01M PSS were investigated.Differences in linear growth were observed between pure water and 0.01M PSS-basedsolutions. The voltemmetric curves show well-defined anodic and cathodic peaks, whichis indicative of both electrocatalytic oxidation and reduction of nitrite.