Electrochimica Acta 46 (2001) 3373 – 3380 Electrochemical study of nickel – aluminium – manganese spinel Ni x Al 1 - x Mn 2 O 4 . Electrocatalytical properties for the oxygen evolution reaction and oxygen reduction reaction in alkaline media J. Ponce a , J.-L. Rehspringer b , G. Poillerat c, * ,1 , J.L. Gautier d, * a Departamento de Quı ´mica, Facultad de Ciencias Ba ´sicas, Uniersidad de Antofagasta, A. Angamos 601, Antofagasta, Chile b Groupe des Mate ´riaux Inorganiques, UMR 7504 CNRS, IPMS, 23, rue du Loess, 67037 Strasbourg, France c Laboratoire d’E ´ lectrochimie et de Chimie Physique du Corps Solide, UMR, ULP/CNRS 7512, Faculte ´ de Chimie, Uniersite ´ Louis Pasteur 1 – 4 rue Blaise Pascal, 67008 Strasbourg, France d Laboratorio de Electroquı ´mica, Departamento de Quı ´mica de los Materiales, Facultad de Quı ´mica y Biologı ´a, Uniersidad de Santiago de Chile, A. L. B. O’Higgins 3363, Santiago, Chile Received 16 January 2001; received in revised form 6 April 2001 Abstract The oxygen reduction reaction and the oxygen evolution reaction have been studied on mixed oxides Ni x Al 1 -x - Mn 2 O 4 (1 x 0) crystallising in the spinel structure. Two different preparation methods have been used: coprecip- itation of metal hydroxides and sol – gel. The different activity that is observed is related to the solid-state couple in octahedral sites. AlMn 2 O 4 shows the poorest activity due to intrinsic resistivity. The substitution of Al by Ni increases the catalytic activity, the maximum being that exhibited by NiMn 2 O 4 . These electrochemical reactions can be used to detect the nature of the electrodes by way of the electrocatalytic activity. © 2001 Elsevier Science Ltd. All rights reserved. Keywords: Electrocatalysis; Mixed oxides; OER; ORR; RRDE www.elsevier.com/locate/electacta 1. Introduction Spinel transition-metal oxides have been identified as promising electrocatalysts for the oxygen reduction re- action (ORR) and the oxygen evolution reaction (OER) [1 – 3]. In these kinds of compound the electrocatalytic properties have been related to the presence of the internal redox couple of the transition metals. As mixed-valence oxides, their cationic distribution is the bridge between solid-state chemistry and the electrocat- alytic properties. In this class of compounds, transition metals can occupy a tetrahedral coordination with the oxygen and/or an octahedral coordination with the oxygen ions. The distribution of the cationic oxidation states within both coordinations depends greatly on the preparation conditions used. Numerous spinel oxides have already been studied. Recently, upon studying cobalt – manganese oxides we have found that man- ganese catalyses the ORR but inhibits the OER [4]. In previous studies [5,6] we have prepared and character- ised aluminium manganite spinels Ni x Al 1 -x Mn 2 O 4 with the aim of determining the effect of aluminium * Corresponding authors. Tel.: +56-2-6812575; fax: +56- 2-6812108. E-mail addresses: gpoiller@chimie.u-strasbg.fr (G. Poillerat), jgautier@lauca.usach.cl (J.L. Gautier). 1 ISE member. 0013-4686/01/$ - see front matter © 2001 Elsevier Science Ltd. All rights reserved. PII:S0013-4686(01)00530-8