Identifying Monomeric Fe Species for Efficient Direct Methane Oxidation to C1 Oxygenates with H2O2 over Fe/MOR Catalysts

Exploring advanced catalysts and reaction systems operated at mild conditions is crucial for conducting the direct methane oxidation toward oxygenate products. Many efforts have been put into research on pentasil−type (MFI) zeolites based mononuclear and/or binuclear iron sites, using H2O2 as oxidant. In this work, we present a modified liquid ion−exchange method to better control Fe loading in mordenite−type (MOR) zeolite with Si/Al molar ratio of 9. The optimized Fe/MOR catalyst showed excellent performance turnover frequencies (TOFs) 555 h−1 C1 oxygenates, significantly than reported activity. Multiple comparative experiments were conducted reveal mechanism behind performance. Strikingly, active sites found be confirmed by transmission electron microscopy (TEM), ultraviolet−visible diffuse reflectance spectroscopy (UV−vis DRS), X-ray absorption (XAS). Increasing led aggregation which tend trigger undesirable side reactions (i.e., decomposition over−oxidation), resulting significant decrease TOFs oxygenates.