Metallo-corroles have shown to have unique catalytic properties for oxygen reduction when adsorbed on a high surface area carbon such as BP2000. The nature of the interaction between carbon surfaces and metallo-corroles has yet to be identified. This work suggests that the catalytic activity lays not in a bond between the carbon surface and the corrole molecule, but rather in the arrangement of corrole molecules within the porous structure of the carbon surface. This hypothesis was studied here using Electron Paramagnetic Resonance (EPR), X-ray diffraction (XRD), UV-VIS spectroscopy, elemental analysis, N2 adsorption and several electrochemical methods. BP2000 carbon was compared to four other carbons with different properties (oxygen surface groups, surface area, porous structure and crystallinity). All of these show that the Fe-corrole that was incorporated in BP2000 tends to adsorb in pores of 20–25 nm in diameter, which allow synergistic effects to take place, and enhance the electrocatalysis of oxygen reduction reaction.
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