Electrochemical study of nickel-aluminium-manganese spinel NixAl1-xMn2O4. Electrocatalytical properties for the oxygen evolution reaction and oxygen reduction reaction in alkaline media

The oxygen reduction reaction and the oxygen evolution reaction have been s tudied on mixed oxides NixAl1-x- Mn2O4 (1 greater than or equal to x greate r than or equal to 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-s tate 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 electrochemic al reactions can be used to detect the nature of the electrodes by way of t he electrocatalytic activity. (C) 2001 Elsevier Science Ltd. All rights res erved.