ELECTROCATALYSIS OF OXYGEN EVOLUTION REDUCTION ON LANIO3 PREPARED BY A NOVEL MALIC ACID-AIDED METHOD/

A kinetic study of the electroformation and electroreduction of oxygen in KOH solutions has been carried out on a LaNiO3 electrode obtained through a malic acid precursor route. The new electrocatalyst was foun d to show greatly enhanced activity for both oxygen evolution and redu ction. The apparent electrocatalytic activity of this electrode for ox ygen reduction was more than 10 times higher than those reported for s imilar electrodes obtained by other methods. It was, however, observed to be less active electrocatalytically for oxygen evolution as compar ed to the active LaNiO3 electrode obtained by the Bockris-Otagawa copr ecipitation method. The electrochemical reaction order with respect to OH- concentration was found to be approximately 1 in the case of oxyg en evolution while that for oxygen reduction, was approximately -1. Th e Tafel slope values for the reactions were similar to 2.3 RT/F and si milar to 2 x 2.3 RT/3F, respectively.