Electrochemical reduction of dioxygen on Alizarin modified glassy carbon electrode in acidic medium

The catalytic behaviour of glassy carbon electrode modified by 1,2-dihydroxy antraquinone (Alizarin) was investigated. The electrocatalytic ability of modified electrode for the reduction of dioxygen was examined by cyclic voltammetry and rotating disk electrode (RDE) voltammetry techniques. The Alizarin modified glassy carbon electrode possesses excellent electrocatalytic abilities for dioxygen reduction over potential 400 mV lower than at the bare glassy carbon electrode. Hydrodynamic studies were performed to determine the heterogeneous rate constant for the reduction of O2 at the surface of modified electrode. It was determined by Koutecky-Levich plot. The apparent diffusion coefficient of O2 in O2 saturated acidic solutions was estimated by using Levich equation. Studies show the involvement of four electrons in dioxygen reduction at the surface of this modified electrode.