Tandem Oxygen Activation for Efficient Aerobic Oxidation: The Underlying Function of Oxide in Metal/Oxide Catalysts

Metal/oxide composites represent efficient catalysts for oxygen activation and aerobic oxidation, with the active site typically recognized as the metal/oxide interface. The oxide distant from the interface (remote oxide), however, is often considered catalytically inert. Here, through rational catalyst design, we demonstrate using selective alcohol oxidation as a model reaction that the remote oxide can actively participate in catalysis by working in tandem with the interface, enabling sequential activation of oxygen into hydroxyl radicals for efficient oxidation. Isotope labeling studies reveal that the interface catalyzes alcohol oxidation to produce aldehyde and H2O2 in the presence of O2. The accumulated H2O2 is subsequently activated on remote oxide to generate hydroxyl radicals, initiating an additional oxidation pathway that accounts for 40.8% of the total alcohol conversion. This work highlights the importance of simultaneous surface and interface structure optimization for advanced metal/oxide catalysts.