Spin Polarization Effects on O2 Dissociation from Heme-O2 Adduct

We consider singlet and triplet iron-porphyrin-O2 (FeP-O2) adducts to investigate spin polarization effects on the FeP-O2 interaction using ab initio calculations based on density functional theory (DFT). The presence of the imidazole (Im) ligand induces spin polarization from O2 to Fe in the triplet (Im)FeP-O2 adduct. The O-O bond of the triplet (Im)FeP-O2 is weaker than that of the triplet FeP-O2 because of this spin polarization effects. Our results suggest that magnetization of heme or heme-based nanomaterials may be utilized as cathode electrode catalysts in polymer electrolyte fuel cells (PEFCs).