The oxygen reduction (ORR) and evolution (OER) reaction at some oxides in alkaline electrolyte

In this study, we tried to investigate the effects of some oxide catalysts for kinetics and mechanism of OER and ORR in alkaline electrolyte (0.1M and 0.5M potassium hydroxide). In order to realize, RRDE was used. From obtained results copper(II)ferrous(III)oxide on GC electrode has the best catalytic activity towards OER and ORR. Although copper(II)ferrous(III)oxide on Ag showed best catalytic activity for OER, in case of ORR manganese(III)oxide showed best performance. We also observed that while electrocatalysts on silver follow four electron direct pathway mechanism, catalysts on glassy carbon follow both direct four electron and indirect two electron pathways. This observation was proved with ring currents and hydrogen peroxide percentage. Besides we derived Levich and Tafel plots to determine e- rates which show the kinetics of ORR.