The oxygen reduction reaction and the oxygen evolution reaction have been studied on mixed oxides Ni x Al1−x Mn2O4 (1≥x≥0) crystallising in the spinel structure. Two different preparation methods have been used: coprecipitation of metal hydroxides and sol–gel. The different activity that is observed is related to the solid-state couple in octahedral sites. AlMn2O4 shows the poorest activity due to intrinsic resistivity. The substitution of Al by Ni increases the catalytic activity, the maximum being that exhibited by NiMn2O4. These electrochemical reactions can be used to detect the nature of the electrodes by way of the electrocatalytic activity.