Electrocatalytic reduction of oxygen on Co3O4: Effects of processing method

Abstract

In this study, cathode materials for oxygen reduction reaction were produced. Co3O4 spinel oxides were synthesized by hydrazine based precursor method. X-ray appearing for 311 plane and lattice parameter a = 8.06 Å diffraction pattern showed cubic crystalline structure with 100% relative intensity. These oxides were supported on vulcan carbon by in situ precursor method and by manually grinding in agate mortar and pestle. Prepared Co3O4/C electrodes were characterized by SEM/EDAX to understand the surface morphology. The electrochemical measurements were made using cyclic voltammetry and steady-state polarization techniques. Oxygen reduction reaction was studied in alkaline solution (6 M KOH) by using Hg/HgO, OH− as the reference electrode. The results have shown lower activity for the ORR on the Co3O4/C species compared to that on Pt/C, but higher activity compared to that of pure vulcan carbon. It is observed that oxygen reduction proceeds via 4 electron transfer for Co3O4/C obtained by photocatalytic decomposition. Keywords: Co3O4, Oxygen reduction, Precursor method, Electrocatalysis, Photocatalytic decomposition