Abstract
Hydroxy radical (•OH) is a prestigious oxidant that allows the cleavage of strong chemical bonds of methane but is untamed, leading to over-oxidation of methane and waste of oxidants, especially at high methane conversion. Here, we managed to buffer •OH in an aqueous solution of photo-irradiated Fe3+, where •OH almost participates in methane oxidation. Due to the interaction between Fe3+ and SO42-, the electron transfer from OH- to excited-state Fe3+ for •OH generation is retarded, while excessive •OH is consumed by generated Fe2+ to restore Fe3+. When combined with a Ru/SrTiO3:Rh photocatalyst, the buffered •OH converts methane to C2+ hydrocarbons and H2 with formation rates of 246 and 418 μmol h-1, respectively. The apparent quantum efficiency reaches 13.0 ± 0.2%, along with 10.2% methane conversion and 81% C2+ selectivity after 80 hours of reaction. Overall, this work presents a strategy for controlling active radicals for selective and efficient photocatalysis.
Published Version
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