Synergistic Defect Engineering and Flexoelectric Effect in Rod-Like Ba1−xSrxTiO3/Co3O4 Heterojunction for Enhanced PMS Activation Toward Tetracycline Degradation

Tetracycline persists extensively in aquatic environments due to its refractory nature, posing a significant threat to ecosystem integrity and human health. However, the practical application of pure BaTiO 3 is limited by low carrier mobility and insufficient active sites. Herein, we synthesized rod-shaped Ba 1−x Sr x TiO 3 /Co 3 O 4 (x = 0.1–0.5) heterojunction catalysts to investigate their degradation performance of tetracycline (TC). Specifically, electron modulation was achieved through Sr doping-induced lattice distortion and oxygen vacancies, which optimized the surface charge state and generated defect dipoles to enhance local polarization. Moreover, the anisotropic rod-like morphology enhanced the flexoelectric effect under ultrasonic stimulation to promote the separation of charge carriers. Furthermore, the construction of low-resistance electronic channels at the Ba 1−x Sr x TiO 3 /Co 3 O 4 heterojunction interface accelerates the Co 2+ /Co 3+ redox cycle. Consequently, TC is effectively degraded with an efficiency of 99.39% by the BST-4/Co 3 O 4 /PMS systems. Furthermore, O 2 ·− was confirmed as the primary reactive oxygen species by free radical capture experiments. This study adopts a strategy that integrates lattice distortion, morphological design and heterostructure construction to effectively enhance the flexoelectric catalytic performance of the material. The approach provides a novel solution for the removal of antibiotics in wastewater. Graphical