Theoretical study of the natural active structure of the Fe-SSZ-13 zeolite and its reactivity toward the methane to methanol oxidation reaction

Abstract

We have employed the DFT method utilizing a cluster model to investigate the reaction mechanism of methane to methanol (MTM) conversion by the Fe-SSZ-13 system. Our calculations have demonstrated that the substitution of the Al pair on 6MR results in the most stable monomeric Fe coordination. Upon examining the entire MTM reaction using Fe-SSZ-13, it was determined that N2O activation represents the rate-determining step, and the energy barrier of the Fe(IV) = O active species activated C–H bond of methane is a mere 4.3 kcal/mol. Subsequently, the radical intermediate is significantly more energetically favorable in generating the methanol product through the OH rebound reaction. Furthermore, utilizing a larger cluster model, the impact of the framework has been shown to promote the key reaction step through its stronger electrostatic interaction.