Constructing Active Cu 2+ -O-Fe 3+ Sites at the CuO-Fe 3 O 4 Interface to Promote Activation of Surface Lattice Oxygen.

Activating surface lattice oxygen (O latt ) through the modulation of metal-oxygen bond strength has proven to be an effective route for facilitating the catalytic degradation of volatile organic compounds (VOCs). Although this strategy has been implemented via the construction of the TM 1 -O-TM 2 (TM represents a transition metal) structure in various reactions, the underlying principle requires exploration when using different TMs. Herein, the Cu 2+ -O-Fe 3+ structure was created by developing CuO-Fe 3 O 4 composites with enhanced interfacial effect, which exhibited superior catalytic activity to their counterparts, with T 90 (the temperature of toluene conversion reaching 90%) decreasing by approximately 50 °C. Structural analyses and theoretical calculations demonstrated that the active Cu 2+ -O-Fe 3+ sites at the CuO-Fe 3 O 4 interface improved low-temperature reducibility and oxygen species activity. Particularly, X-ray absorption fine structure spectroscopy revealed the contraction and expansion of Cu-O and Fe-O bonds, respectively, which were responsible for the activation of the surface O latt . A mechanistic study revealed that toluene can be oxidized by rapid dehydrogenation of methyl assisted by the highly active surface O latt and subsequently undergo ring-opening and deep mineralization into CO 2 following the Mars-van Krevelen mechanism. This study provided a novel strategy to explore interface-enhanced TM catalysts for efficient surface O latt activation and VOCs abatement.