Regulating Spin Polarization through Cationic Vacancy Defects in Bi 4 Ti 3 O 12 for Enhanced Molecular Oxygen Activation

Molecular oxygen (O ) activation technology is of great significance in environmental purification due to its eco-friendly operation and cost-effective nature. However, the activation of O is limited by spin-forbidden transitions, and efficient molecular oxygen activation depends on electronic behavior and surface adsorption. Herein, we prepared cationic defect-rich Bi Ti O (BTO-MV2) catalysts containing Ti vacancies (V ) for O activation in water purification. The V 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 V is also formed, serving as a center for adsorbing O and extracting electrons, effectively generating ⋅OH, O ⋅ and O . 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.