Biomimetic Oxidation with Fe-ZSM-5 and H2O2? Identification of an Active, Extra-Framework Binuclear Core and an FeIII-OOH Intermediate with Resonance-Enhanced Raman Spectroscopy

Developing inorganic materials that can mimic nature's ability to selectively oxidise inert CH bonds remains a topic of intense scientific research. In recent years, zeolitic materials containing Fe and/or Cu have been shown to be highly active, heterogeneous catalysts for the selective oxidation of alkanes (including methane), amongst a range of other related oxidation challenges. By using resonance-enhanced Raman spectroscopy, we demonstrate that, following high-temperature pre-treatment (activation), Fe-containing ZSM-5 possesses an active binuclear core, and forms a key FeOOH intermediate upon activation with H2O2. Both factors are reminiscent of biological oxidation catalysts, and may account for the unique ability of this material to selectively oxidise methane to methanol at low temperature.