Comparative Study of Different Methods for the Preparation of CoxOy/C for the Electrosynthesis of Hydrogen Peroxide

A comparative study of the sol-gel method (SGM) and polymeric precursor method (PPM) for the synthesis of CoxOy/C electrocatalysts has been performed. CoxOy/C electrocatalysts can electrogenerate hydrogen peroxide (H2O2), which is desirable for the electrochemical treatment of effluent containing organic pollutants in aqueous or non-aqueous medium. The results showed that SGM was superior for the synthesis of CoxOy/C catalysts for H2O2 electrogeneration. Analysis of X-ray diffraction for CoxOy/C prepared by PPM identified only one phase comprising Co3O4. Besides for CoxOy/C prepared by SGM a mixture of oxides was observed: CoO and Co2O4. The average size of crystallites in this material was 5 nm. A rotating ring-disc electrode was used for electrochemical analysis of the oxygen reduction reaction (ORR). The results showed that the SGM was better than PPM for H2O2 electrogeneration since it showed the highest ring-currents. Results also indicate that the number of electrons transferred in the ORR for SGM and PPM were 2.4 and 3.5, while the percentage of H2O2 formed was 78 % and 23 %, respectively. The results were obtained in a 1 M NaOH and 1 M H2SO4 electrolytes. CoxOy/C synthesized with SGM is a promising material for the production of H2O2.