Selective photocatalytic oxidative coupling of methane via directional activation of oxygen over Au-loaded ZnSn-LDH with defect structure

The selective photocatalytic oxidative coupling of methane (OCM) holds great potential in converting low-cost feedstock into C 2 products. However, the challenge lies in improving the photocatalytic OCM activity through catalyst design and gaining a deeper understanding of reactant activation in the OCM process. Here, we synthesized Au-ZnSn-LDH with oxygen vacancies to achieve efficient selective oxidation of methane using O 2 . The optimal hybrid exhibits a C 2 H 6 yield of 2666 μmol g −1 h −1 and 76.8 % selectivity . Our findings showed that the oxygen within the surface of ZnSn-LDH (possibly from adsorption at O v vacancy sites) provides sites for the evolution of O 2 to O 2 − with assistance from Au cocatalyst . More O 2 − could be generated from O 2 provides a desired reactivity to selectively promote selective C−H activation of CH 4 under photoexcitation . The Au cocatalyst plays crucial roles in facilitating the methyl transfer and promoting C−C coupling to produce C 2 H 6 as the main product while avoiding undesirable overoxidation. Loading Au NPs on the 2D-layered ZnSn-LDH enables highly efficient conversion of CH 4 to high value-added ethane. It has been suggested that controlling oxygen species is an effective approach for producing C 2 H 6 with high activity and selectivity. • Au-loaded ZnSn-layered double hydroxides with a defect structure were synthesized. • The hybrid enables the oxidative coupling of methane through directional activation of oxygen. • The involvement of O 2 − radical is essential for facilitating the selective C−H activation of CH 4 . • The presence of Au cocatalyst and O v vacancies ensures a high-rate conversion of CH 4 to C 2 H 6 .