2025 Volume 4 Issue 2 Pages 144-153
Iron phthalocyanine (FePc), a molecular catalyst, has attracted considerable interest for its role in the oxygen reduction reaction (ORR) in fuel cells and various other applications. The incorporation of FePc on carbon materials increases its ORR activity considerably. However, the specific factors that affect this activity remain poorly understood because of a lack of data on the carbon supports. To improve the ORR catalytic performance of the Fe–N4 structure, we systematically examined the structural parameters of the carbon supports that influence the ORR activity of FePc. The results show that all carbon-supported FePc catalysts had a higher ORR activity than bulk FePc powder. The ORR current was found to be related to the quantity of electrochemically active FePc, as determined by cyclic voltammetry, rather than the total amount of loaded FePc. In addition, the quantity of electrochemically active FePc increased with the size of the carbon layer. The onset potential for the ORR also varied with different carbon supports, with Ketjenblack (KB) having the highest value. Transmission electron microscopy and small-angle X-ray scattering measurements identified a hollow spherical structure for KB, with an average diameter of 44.8 nm. X-ray absorption fine structure analysis indicated that the FePc supported on KB was curved. Therefore, our study provides insights into the key factors related to carbon supports that increase the ORR activity of FePc.
