Synergy of Ag and AgBr in a Pressurized Flow Reactor for Selective Photocatalytic Oxidative Coupling of Methane.

Oxidation of methane into valuable chemicals, such as C2+ molecules, has been long sought after but the dilemma between high yield and high selectivity of desired products remains. Herein, methane is upgraded through the photocatalytic oxidative coupling of methane (OCM) over a ternary Ag-AgBr/TiO2 catalyst in a pressurized flow reactor. The ethane yield of 35.4 µmol/h with a high C2+ selectivity of 79% has been obtained under 6 bar pressure. These are much better than most of the previous benchmark performance in photocatalytic OCM processes. These results are attributed to the synergy between Ag and AgBr, where Ag serves as an electron acceptor and promotes the charge transfer and AgBr forms a heterostructure with TiO2 not only to facilitate charge separation but also to avoid the overoxidation process. This work thus demonstrates an efficient strategy for photocatalytic methane conversion by both the rational design of the catalyst for the high selectivity and reactor engineering for the high conversion.