Regulating Spin Polarization through Cationic Vacancy Defects in Bi4Ti3O12 for Enhanced Molecular Oxygen Activation.

Molecular oxygen (O2) activation technology is of great significance in environmental purification due to its eco‐friendly operation and cost‐effective nature. However, the activation of O2 is limited by spin‐forbidden transitions, and efficient molecular oxygen activation depends on electronic behavior and surface adsorption. Herein, we prepared cationic defect‐rich Bi4Ti3O12 (BTO‐MV2) catalysts containing Ti vacancies (VTi) for O2 activation in water purification. The VTi on BTO nanosheets can induce electron spin polarization, increasing the number of spin‐down photogenerated electrons and reducing the recombination of electron‐hole pairs. An active surface VTi is also formed, serving as a center for adsorbing O2 and extracting electrons, effectively generating ⋅OH, O2⋅− and 1O2. The degradation rate constant of tetracycline achieved by BTO‐MV2 is 3.3 times faster than BTO, indicating a satisfactory prospect for practical application. This work provides an efficient pathway to activate molecular oxygen by constructing new active sites through cationic vacancy modification technology. [ABSTRACT FROM AUTHOR]