Accelerated activation of lattice oxygen for CO Oxidation: Promoting the role of oxygen vacancies

The role of surface oxygen sites in transition metal oxides has been a focal point in environmental and energy chemistry, particularly in catalytic oxidation reactions. Herein, the mobility and activation of lattice oxygen in MnCo₂O₄ were effectively modulated via in situ thermal treatment for CO oxidation. By weakening the metal–oxygen bond strength, active surface lattice oxygen was generated, which could be readily activated to participate in the catalytic oxidation of CO to CO₂. The increased covalency of Co − O bonds not only improves the Co 3d − O 2p electronic structure but also generates active oxygen species on the surface, which are efficiently involved in the catalytic oxidation of CO to CO₂, as demonstrated by soft XAS, XPS, and O₂-TPD analyses. Our findings offer a reliable understanding of the dual activation process involving lattice and defect oxygen in heterogeneous catalytic oxidation reactions and provide a solid foundation for strategies aimed at enhancing catalytic oxidation activity.