Construction of MnOₓ catalysts rich in oxygen vacancies for highly selective oxidation of aromatic alcohols: Structure-activity relationship and mechanism study

Developing highly efficient and stable non-precious metal oxide catalysts for selective oxidation reactions remains a key challenge in the field of heterogeneous catalysis. This study synthesized a series of manganese oxide catalysts with distinct structural characteristics by controlling the calcination temperature of the precursors. The results indicate that the calcination temperature significantly influences the catalyst's crystal structure, the distribution of manganese valence states, and the surface defect concentration. Among these, the manganese oxide calcined at 400 °C exhibits optimal catalytic performance due to its unique structural characteristics, which include residing at a phase transition boundary, a partial transition of Mn ion valence states, and the resulting abundance of surface oxygen vacancies. These structural features collectively regulate the catalyst's electronic structure, effectively promoting the adsorption, and activation of molecular oxygen. This generates superoxide radicals (·O 2 – ) as key reactive oxygen species, thereby driving an efficient oxidation reaction cycle. This work elucidates the structure–activity relationship of manganese oxides in oxidative catalysis, providing important insights for designing metal oxide catalysts with specific surface defects and electronic properties.