Photofunctionalization of Light Alkanes by FeO_x/BCN at 12 °C

The activation of methane and other gaseous hydrocarbons at low temperature remains a substantial challenge for the chemistry community. Here, we report an anaerobic photosystem based on crystalline borocarbonitride (BCN) supported Fe-O nanoclusters, which can selectively functionalize C-H bonds of methane, ethane, and higher alkanes to value-added organic chemicals at 12 °C. Scanning transmission electron microscopy and X-ray absorption spectroscopy corroborated the ultrafine FeOOH and Fe₃O₄ species in Fe-O clusters, which enhanced the interfacial charge transfer/separation of BCN as well as the chemisorption of methane. Mechanism studies with in situ diffuse reflectance infrared Fourier transform spectroscopy and density functional theory calculations unveiled methane bonding and polarization on the Lewis acid-base sites of terminal iron hydroxyl, essentially lowering the energy barriers of C-H activation. Catalyzed in tandem with chlorine radical initiated by BCN, C-H bond homolysis of methane, ethane, and higher alkanes proceeded smoothly, affording amination, alkylation, and arylation products in a manner of broad substrate scope (36 examples). This study offers a promising pathway of heterogeneous photocatalysis for the sustainable transformation of natural gases with minimized energy consumption and high efficiency.