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

Photo-driven CH4 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 CH4 conversion and H-2 production using iron ions. A photo-driven iron-induced reaction system was developed, which is efficient at selective coupling of CH4 as well as conversion of benzene and cyclohexane under mild conditions. For CH4 conversion, 94 % C-2 selectivity and a C2H6 formation rate of 8.4 mu mol h(-1) is achieved. Mechanistic studies reveal that CH4 coupling is induced by hydroxyl radical, which is generated by photo-driven intermolecular charge migration of an Fe3+ complex. The delicate coordination structure of the [Fe(H2O)(5)OH](2+) complex ensures selective C-H bond activation and C-C coupling of CH4. The produced Fe2+ can be used to reduce the potential for electrolytic H-2 production, and then turns back into Fe3+, forming an energy-saving and sustainable recyclable system.

Automated summary

We constructed a solar-energy-driven redox cycle using iron ions as catalysts for the combination of CH4 conversion and H2 production. A photo-driven iron-induced reaction system was developed, which showed high efficiency in the selective coupling of CH4, benzene, and cyclohexane under mild conditions. Mechanistic studies revealed that CH4 coupling was induced by hydroxyl radical generated by photo-driven intermolecular charge migration of an Fe3+ complex. The produced Fe2+ was used to reduce the potential for electrolytic H2 production and then turned back into Fe3+, forming an energy-saving and sustainable recyclable system.