Selective PhotocatalyticAerobic Oxidation of Methaneto Methyl Hydroperoxide by ZnO-Loaded Single-Atomic Ruthenium OxideCatalyst

Photooxidation of CH₄ to value-added chemicals with high selectivity offers a promising pathway to drive the rational utilization of natural gas resources with renewable energy under mild conditions. However, owing to the poor chemoselectivity of reactive oxygen radical formation and consecutive side reactions of primary products, the synthesis of peroxide directly from CH₄ oxidation remains challenging. Here, we report single-atom ruthenium oxide-doped ZnO as a highly selective photocatalyst for the aerobic oxidation of CH₄ to CH₃OOH. Under optimal conditions, the CH₃OOH formation rate over Ru₁O_<i>x</i>/ZnO reaches 321 μmol g_cat^–1 h^–1 with a high selectivity of 90.9% under simulated solar irradiation. Mechanistic studies reveal that the selective generation of •OOH radicals via oxygen reduction and the ability to prevent secondary side reactions of CH₃OOH are the main advantages of Ru₁O_<i>x</i>/ZnO, accounting for the remarkable selectivity of CH₃OOH from CH₄. The single-atom Ru oxide/ZnO catalyst also exhibits remarkable chemoselectivity to alkyl hydroperoxide in the photocatalytic oxidation of low paraffins, which provides a solution to prepare value-added peroxide from a single-step oxidation of hydrocarbon substrates.