Photo-Driven Iron-Induced Non-Oxidative Coupling of Methane to Ethane.

Photo-driven CH 4 conversion to multi-carbon products and H 2 is attractive but challenging, and the development of efficient catalytic systems is critical. Herein, we construct a solar-energy-driven redox cycle for combining CH 4 conversion and H 2 production using iron ions. A photo-driven iron-induced reaction system was developed, which is efficient at selective coupling of CH 4 as well as conversion of benzene and cyclohexane under mild conditions. For CH 4 conversion, 94 % C 2 selectivity and a C 2 H 6 formation rate of 8.4 μmol h -1 is achieved. Mechanistic studies reveal that CH 4 coupling is induced by hydroxyl radical, which is generated by photo-driven intermolecular charge migration of an Fe 3+ complex. The delicate coordination structure of the [Fe(H 2 O) 5 OH] 2+ complex ensures selective C-H bond activation and C-C coupling of CH 4 . The produced Fe 2+ can be used to reduce the potential for electrolytic H 2 production, and then turns back into Fe 3+ , forming an energy-saving and sustainable recyclable system.