Electrochemical Formation of Fe(IV)=O Derived from H2O2 on a Hematite Electrode as an Active Catalytic Site for Selective Hydrocarbon Oxidation Reactions

The high-valence iron species (Fe(IV)=O) in the cytochrome P450 enzyme superfamily is generated via the activation of O-2, and serves as the active center of selective hydrocarbon oxidation reactions. Furthermore, P450 can employ an alternate route to produce Fe(IV)=O, even from H2O2 without O-2 activation. Meanwhile, Fe(IV)=O has recently been revealed to be the reactive intermediate during H2O oxidation to O-2 on hematite electrodes. Herein, we demonstrated the generation of Fe(IV)=O on hematite electrodes during the electrochemical oxidative decomposition of H2O2 using in situ UV-visible absorption spectra. The generation of Fe(IV)=O on hematite electrodes from H2O2 exhibited 100 mV lower overpotential than that from H2O. This is because H2O2 serves not only as the oxygen source of Fe(IV)=O, but also as the additional oxidant. Finally, we confirmed that the Fe(IV)=O generated on hematite electrodes can serve as the catalytic site for styrene epoxidation reactions.