Non-Precious Metal Catalyst That Combines Perovskite-Type Oxide and Iron Phthalocyanine for Use as a Cathode Catalyst in an Alkaline Fuel Cell

Abstract

A non-precious metal catalyst was obtained by combining a perovskite-type oxide-carbon mixture (La0.6Sr0.4MnO3/C, La0.6Sr0.4CoO3/C, and La0.6Sr0.4Mn0.7Co0.3O3/C) and an iron phthalocyanine complex (Fe-Pc) with two-by-two electron O2 reduction activity. The oxygen reduction reaction (ORR) activities of the Fe-Pc/perovskite/C catalysts were investigated in alkaline media using rotating ring-disk electrode (RRDE) method. Although all of the Fe-Pc/perovskite/C catalysts showed enhanced ORR activities with a positive shift of the onset potential compared to perovskite/C and Fe-Pc/C, the number of electrons during ORR was different due to the HO2− reduction activity of the perovskite/C. Among the prepared catalysts, the Fe-Pc/La0.6Sr0.4Mn0.7Co0.3O3/C catalyst exhibited the highest catalytic activity, which was comparable to that of the Pt/C catalyst. Furthermore, oxygen reduction on this catalyst proceeds thorough an efficient 2+2 pathway with the formation of only a very small fraction of HO2− (0.5–3%).