Preparation of ordered mesoporous F–H2Ti3O7 nanosheets using orthorhombic HTiOF3 as a precursor and their highly efficient degradation of tetracycline hydrochloride under simulated sunlight

In this study, the transformation relationship between HTiOF 3 and TiOF 2 under hydrothermal conditions was discussed first. With the progress of hydrothermal reaction , HTiOF 3 with small hexagonal structure gradually transformed into TiOF 2 with large cubic structure. Secondly, the effects of alkaline hydrothermal treatment and ion-exchange treatment on the phase and morphology of HTiOF 3 and TiOF 2 were investigated. It was confirmed that hexagonal HTiOF 3 can be used as precursor to prepare fluorine doped H 2 Ti 3 O 7 (F–H 2 Ti 3 O 7 ) nanosheets with ordered mesoporous structure by simple alkaline hydrothermal and ion-exchange methods. The prepared F–H 2 Ti 3 O 7 nanosheets have ordered mesoporous structure, providing a high specific surface area of 404.08 m 2 /g and a macroporous volume of 0.46 cm 3 /g. F–H 2 Ti 3 O 7 can be adsorb tetracycline hydrochloride (TCH) on its surface and then degraded it via photocatalytic processes. Furthermore, herein for the first time the photocatalytic degradation path of TCH by F–H 2 Ti 3 O 7 through the synergistic effect of sensitization and LMCT was proposed. Besides, the reusability study showed that F–H 2 Ti 3 O 7 has the ability to degrade the tetracycline hydrochloride efficiently after five cycles and slightly its high degradation rate change from 92.90% to 82.10% under simulated sunlight. In addition, F–H 2 Ti 3 O 7 has good sedimentation performance, which provides the possibility for the practical application of the photocatalyst .