ON THE CATALYTIC PROPERTIES OF MIXED OXIDES FOR THE ELECTROCHEMICAL REDUCTION OF OXYGEN

Mixed oxides of the perovskite structure have been synthesized and their efficiency as catalysts for the reduction of oxygen at a carbon electrode in 6 M KOH has been studied. The magnetic susceptibility has been measured for the oxides before use and a formal magnetic moment calculated. No obvious correlation between the measured quantities was found. Possibly some arguments can be given for the existence of a minimum of catalytic effect for magnetic moments of about 1.8 Bohr magnetons. This value is suggested to correspond to the similar quantity of superoxide ion O2-, indicating an unfavourable interaction between catalyst and this reaction intermediate having equal number of unpaired electrons. © 1990.