Catalytic Characteristics of β-Iron Phthalocyanine Prepared by Vacuum Heat Treatment for Fuel Cell Oxygen Reduction Reaction

Non-precious metal catalyst materials such as carbon-based catalysts and transition metal chelate compounds have been investigated for reducing the cost of polymer electrolyte fuel cells (PEFCs). Our research on the synthesis of such catalysts has involved vacuum heat treatment for the preparation of iron phthalocyanine (FePc). When a composite of FePc and Ketjenblack carbon was synthesized by vacuum heat treatment at ≥350°C for 10 h, FePc was deposited as a thin film on the Ketjenblack. Furthermore, synthesis with the vacuum heat treatment at 400°C for 10 h (FePc/C-400) transformed the FePc structure from the α phase to the β phase. The oxygen reduction reaction (ORR) activity of FePc/C-400 was higher than those of other FePc/C catalysts treated at different temperatures. The coordination of Fe and N in β-FePc was found to be related to the high ORR activity.