Films of mixed valency oxides Ni x Co3−x O4 (1≥x≥0.1) were studied in alkaline solutions for the indirect oxidation of ethylene glycol (EG) by peroxide anions HO2 − resulting from the cathodic reduction of O2. It was found that the electrocatalytical activity of the oxides correlated to nominal Co3+/Co2+ content ratio in the spinel structure and that the oxide Ni0.3Co2.7O4, which presents the highest Co3+/Co2+ ratio, was the most effective in the series.