Constructing MnO2–CuMn2O4 interfaces to enhance the activation of surface lattice oxygen for efficient toluene combustion

Abstract

Activating surface lattice oxygen by establishing interfaces between transition metal oxides has been identified as an effective route to boost the catalytic purification of volatile organic compounds (VOCs). Herein, MnO₂ was in situ grown on CuMn₂O₄ (MnO₂/CMO) with an interfacial effect for high-efficiency oxidation of toluene. The introduction of MnO₂ regulated the coordination environment of MnO₂/CMO, resulting in a decrease in the electron cloud density around oxygen atoms and consequently weakening the Mn–O bonds. These micro-structural changes facilitated the formation of oxygen vacancies and simultaneously expedited electron transfer and the activation of surface lattice oxygen. Theoretical calculations have verified that the improved toluene adsorption can be explained by the strong p–d orbital hybridization and the upshift of the d-band center near the Fermi level in MnO₂/CMO. In situ diffuse reflectance infrared Fourier transform spectroscopy proved that MnO₂/CMO significantly enhanced the toluene oxidation reaction through highly active lattice oxygen and its rapid replenishment with gaseous oxygen.