Layer-by-layer assembly of multilayer films consisting of silicotungstate and a cationic redox polymer on 4-aminobenzoic acid modified glassy carbon electrode and their electrocatalytic effects Original Research Article

A novel 4-aminobenzoic acid (4-ABA) monolayer film is formed on glassy carbon electrode (GCE) by amino cation radical method. Silicotungstic heteropolyanion (SiW12O404−, denoted as SiW12)-containing multilayer films have been fabricated on the 4-ABA modified GCE surface by alternate deposition with a quaternized poly(4-vinylpyridine) partially complexed with [Os(bpy)2Cl]2+/+ (denoted as QPVP-Os). Cyclic voltammetry (CV), X-ray photoelectron spectroscopy (XPS) and X-ray reflectivity (XR) have been used to characterise the as-prepared multilayer films. It is proved that the multilayer films are uniform and stable. The average thickness for a bilayer of QPVP-Os/SiW12 in the multilayer film is 30.2 Å. The electrocatalytic activities of the multilayer films have been investigated on the reduction of three substrates of important analytical interests, HNO2, BrO3− and H2O2. Especially, the influence of layer number of the multilayer films on the electrocatalytic reduction of HNO2 has been investigated in detail.