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·g_cat^–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 OCH_x–CH_x coupling between them to form the key CH₃CH₂O* intermediate for C₂H₅OH production, as opposed to the conventional CH_x–CO coupling pathway that primarily yields acetic acid.