LAUSR

The effect of coordination sphere around metal centers on oxygen reduction reaction (ORR) activity of transition metal macrocyclic complexes is still unclear. Here we investigate the aromaticity/antiaromaticity effect of macrocycles on ORR activity based on TM norcorrole (TM = Mn, Fe, Co, Ni), TM porphycene and TM porphyrin by first principle calculations. It is found that the complexes with weaker aromatic macrocycles exhibit a stronger adsorption strength while the complexes with antiaromatic macrocycles show further enhanced adsorption strengths. Further investigations indicate that the variation in the adsorption strengths of catalysts is attributed to the different redox activities of macrocycles with different aromaticities. Such difference in redox activities of macrocycles is reflected in activities of metal centers via d-π conjugation, which plays a bridge role between π-electrons on macrocycles and active d-electrons on metal centers. This work deepens the understanding of the role of macrocycles in oxygen electroreduction.