Electrochemical Characterization of Electropolymerized Film of Naphthol Green B and Its Electrocatalytic Activity toward NADH Oxidation

Abstract

A stable electroactive thin film of poly(naphthol green B) (PNGB) was deposited on the surface of a glassy carbon electrode by cyclic voltammetry from an aqueous solution containing naphthol green B (NGB). Cyclic voltammograms of PNGB indicated the presence of a couple of well-defined redox peaks with the formal potential of −50 mV (20 mV s−1). The formal potential shifts linearly in the negative direction with increasing solution pH, with a slope of −56.3 mV per pH unit. The PNGB-modified glassy carbon electrode shows excellent electrocatalytic activity toward NADH oxidation in Britton-Robinson buffer solution (pH 7.0) with an overpotential ca. 480 mV lower than that of the bare electrode. The catalytic rate constant of the modified glassy carbon electrode for the oxidation of NADH is determined by rotating-disk electrode measurements.