Electrocatalytic properties of glassy carbon electrodes modified with hydroxy derivatives of 9,10-anthraquinone for oxygen reduction reaction

The electrochemical and electrocatalytic behavior of glassy carbon electrodes modified by one mono and four dihydroxy derivatives of anthra-9,10-quinone compounds have been investigated by cyclic voltammetric technique. The stability of the modified electrodes was ascertained in acidic and neutral media. The surface morphology of modified electrode was characterized by scanning electron microscope. The influence of pH on the electrochemical and electrocatalytic behavior was studied and pH 6.0 or 7.0 was chosen as the optimum working pH by comparing the shift in oxygen reduction potential. The anthraquinone-adsorbed glassy carbon electrodes possess excellent electrocatalytic ability for oxygen reduction with overpotential ranging from 388 to 547 mV lower than that at a plain glassy carbon electrode. Hydrodynamic volatammetric studies were performed to determine the heterogeneous rate constants for the reduction of O2 at the surface of the modified electrodes, mass specific activity of the anthraquinones used, and the apparent diffusion coefficient of O2 in buffered aqueous O2-saturated solutions.