Electrocatalysis of oxygen reduction by Cu-containing polymer films on glassy carbon electrodes

The catalytic activity of poly [(2,2'-bipyridine)copper(II)-mu(4)-oxalato] coated on a glassy carbon electrode (GCE) for O-2 electroreduction is examined using cyclic voltammetry and rotating disk electrode techniques. The cyclic voltammograms show that O-2 is electroreduced on pBpCuOx-coated GCE surfaces at a peak potential of -0.25 V in pH 4.7 acetate buffer media. The electroreduction. of O-2 on pBpCuOx-coated GCE occurs at 450 mV more positive potential than that found at a bare GCE. The catalytic activity originates from Cu(II) coordinated by bipyridine in the complexes and the polymer type Cu-complex films exhibit an enhanced stability compared to monomeric Cu-complexes during the O-2 electroreduction. The rotating disk electrode measurements reveal that the electroreduction. Of O-2 on pBpCuOx-coated GCE is a four-electron process. Kinetic parameters for O-2 reduction on pBpCuOx-coated GCE are obtained from rotating disk experiments and compared with those on bare glassy carbon electrode surfaces.