N 4-chelates as electrocatalyst for cathodic oxygen reduction

Abstract

N 4-chelates have been investigated as catalysts for the cathodic reduction of oxygen in acid solution. The catalytic activity is influenced by the structure of the macrocyclic ring system, by the kind of the central atom and by the support material. Chelates containing iron and cobalt in connection with active carbon are the prevalent materials. The activity, stability and the selectivity of the catalyst selected can be increased by thermal treatment in inert gas (argon) up to 1000°C. Physical, spectroscopical and analytical investigations were made to elucidate this effect. Hypotheses are discussed about the structure of the active component after the thermal treatment on the basis of these results.