Cover Feature: Revealing Significant Electronic Effects on the Oxygen Reduction Reaction with Iron Porphyrins (ChemSusChem 3/2025)

The Cover Feature shows the different reactivity of electron-rich FeIII-superoxo and electron-deficient FeIII-superoxo formed upon the binding of O2 on Fe porphyrins. The former can undergo smooth protonation, but the latter requires further reduction at more cathodic potentials to give FeIII-peroxo for protonation. This reactivity difference of FeIII-superoxo leads to the different catalytic O2 reduction behaviors of Fe porphyrins. More information can be found in the Research Article by R. Cao and co-workers.