Adjacent Metal Sites Steering Sequential C–H Activation and C–C Coupling for Efficient Methane Conversion to Ethanol

The selective oxidation of CH4 to C2 oxygenates under mild conditions is a significant pathway for CH4 valorization, yet it remains extremely challenging due to the inertness of methane, the competing overoxidation, and sluggish C–C coupling kinetics. Here, we show that the N,S co-doped carbon nanotube-supported Fe5 clusters catalyst (Fe5/NSC) with adjacent Fe sites drives sequential C–H activation and C–C coupling to ethanol with a C2H5OH productivity of 1939.6 μmol·gcat–1·h–1 and a selectivity of 83.9% at 25 °C and 0.5 MPa CH4 without the assistance of CO. Comprehensive experimental investigation and density functional theory calculations reveal the critical role of adjacent Fe sites in the selective formation of C2H5OH. The adjacent Fe sites featured in Fe5/NSC synergistically facilitate the dissociation and/or partial oxidation of CH4 to distinct C1 intermediates (*OCH2 and *CH3) and subsequent OCHx–CHx coupling between them to form the key CH3CH2O* intermediate for C2H5OH production, as opposed to the conventional CHx–CO coupling pathway that primarily yields acetic acid.